{"gene":"ABCA1","run_date":"2026-04-28T17:12:36","timeline":{"discoveries":[{"year":1999,"finding":"ABC1/ABCA1 was identified as the gene defective in Tangier disease through combined gene expression microarray analysis, genetic mapping, and biochemical studies. Blocking ABC1 expression or activity reduces apolipoprotein-mediated lipid efflux from cultured cells, while increasing ABC1 expression enhances it. ABC1 protein is incorporated into the plasma membrane in proportion to its expression level.","method":"Gene expression microarray, genetic mapping, loss-of-function (siRNA/antibody), gain-of-function overexpression, plasma membrane fractionation","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods, replicated across independent labs in concurrent papers","pmids":["10525055","10431236","10431237","10431238"],"is_preprint":false},{"year":1999,"finding":"Mutations in ABC1 were identified as the major cause of both Tangier disease and familial HDL deficiency associated with defective cholesterol efflux, establishing ABC1/ABCA1 as essential for HDL formation and the cholesterol efflux regulatory pathway.","method":"Genomic sequencing, restriction-fragment length polymorphism, cellular cholesterol efflux assay","journal":"Lancet","confidence":"High","confidence_rationale":"Tier 2 — direct mutation identification with functional validation in patient fibroblasts, replicated by multiple independent groups","pmids":["10533863","10535983"],"is_preprint":false},{"year":2000,"finding":"ABCA1 expression drives specific binding of lipid-free apoA-I at the cell surface. Chemical cross-linking and immunoprecipitation showed apoA-I binds directly to ABCA1 protein. ABCA1 preferentially binds lipid-free apoA-I but not HDL. Cells overexpressing ABCA1 display plasma membrane protrusions (echinocyte-like morphology) consistent with excess lipids in the outer membrane leaflet, suggesting ABCA1 acts as a phospholipid/cholesterol flippase.","method":"Chemical cross-linking, co-immunoprecipitation, radiolabeled lipid efflux assay, immunofluorescence confocal microscopy, apoA-I binding assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 — direct binding demonstrated by cross-linking/co-IP plus functional efflux assay in transfected cells","pmids":["10918065"],"is_preprint":false},{"year":2000,"finding":"ABC1 promotes Ca2+-induced exposure of phosphatidylserine at the plasma membrane outer leaflet and facilitates membrane microvesiculation and transbilayer redistribution of phospholipids. ABC1-deficient macrophages have impaired ability to engulf apoptotic cells, while ABC1 transfectants acquire phagocytic behavior, linking ABCA1-driven phosphatidylserine redistribution to apoptotic cell clearance.","method":"In vivo loss-of-function (ABC1-deficient mice), in vitro gain-of-function (transfection), prothrombinase assay, membrane microvesiculation assay, spin-labeled phospholipid transbilayer redistribution, phagocytosis assay","journal":"Nature cell biology","confidence":"High","confidence_rationale":"Tier 1-2 — orthogonal in vivo and in vitro models with multiple biochemical readouts","pmids":["10878804"],"is_preprint":false},{"year":2000,"finding":"LXRα/RXR and LXRβ/RXR heterodimers bind to a direct repeat spaced by four nucleotides (DR4) element at positions -70 to -55 bp in the ABCA1 promoter and drive sterol-dependent transactivation. Mutations in this DR4 element abolish sterol-mediated activation, establishing LXR/RXR as direct transcriptional regulators of ABCA1.","method":"Promoter-reporter transfection assay, site-directed mutagenesis of promoter, co-transfection with LXR/RXR expression vectors","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 — promoter mutagenesis plus receptor co-transfection with multiple sterol conditions","pmids":["10858438"],"is_preprint":false},{"year":2000,"finding":"RXR heterodimers with oxysterol receptors (LXRs) regulate reverse cholesterol transport by controlling expression of the ABC1 transporter in peripheral tissues, while RXR/FXR heterodimers regulate bile acid synthesis. Treatment of animals with rexinoids markedly inhibited cholesterol absorption and repressed bile acid synthesis through these pathways.","method":"Receptor-selective agonist pharmacology in mice, tissue cholesterol balance measurements, gene expression analysis","journal":"Science","confidence":"High","confidence_rationale":"Tier 2 — in vivo pharmacology with receptor-selective agonists and multiple metabolic endpoints, highly cited","pmids":["10968783"],"is_preprint":false},{"year":2002,"finding":"cAMP/PKA-dependent pathway phosphorylates ABCA1, with maximum phosphorylation reached within 10 minutes representing a 260% increase over basal levels. PKA inhibitor H-89 reduced cholesterol efflux by 70% and almost completely inhibited ABCA1 phosphorylation. Tangier disease (homozygous ABCA1-deficient) cells showed no increase in ABCA1 phosphorylation or efflux upon cAMP stimulation, whereas familial HDL deficiency heterozygotes retained partial response.","method":"Radiolabeled phosphorylation assay, cholesterol efflux assay, PKA inhibitor (H-89), patient fibroblasts (Tangier disease and familial HDL deficiency)","journal":"Journal of lipid research","confidence":"High","confidence_rationale":"Tier 2 — direct phosphorylation assay with pharmacological inhibition and genetic controls (Tangier fibroblasts)","pmids":["12454270"],"is_preprint":false},{"year":2003,"finding":"RARγ/RXR directly activates the ABCA1 promoter through the same DR4 element used by LXR/RXR. Chromatin immunoprecipitation in macrophages confirmed binding of RARγ/RXR to the ABCA1 promoter DR4 element in the presence of all-trans retinoic acid. In RARγ-knockout macrophages, marked upregulation of RARα compensated and still induced ABCA1.","method":"Promoter-reporter transfection, chromatin immunoprecipitation (ChIP), RARγ knockout mouse macrophages, dose-response with retinoic acid receptor agonists","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1-2 — ChIP plus genetic KO rescue and reporter assay, multiple orthogonal methods","pmids":["14560020"],"is_preprint":false},{"year":2004,"finding":"Probucol inhibits ABCA1-mediated cholesterol efflux by impairing translocation of ABCA1 from intracellular compartments to the plasma membrane. Probucol also inhibits formation of an ABCA1-linked cholesterol oxidase-sensitive plasma membrane domain and reduces cell-surface apoA-I binding. This effect was absent in Tangier patient fibroblasts lacking functional ABCA1, confirming specificity.","method":"Fluorescent confocal microscopy, biotinylation surface assay, cholesterol oxidase-sensitive domain assay, radiolabeled apoA-I binding assay, Tangier fibroblast controls","journal":"Arteriosclerosis, thrombosis, and vascular biology","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods with Tangier disease genetic control","pmids":["15514211"],"is_preprint":false},{"year":2004,"finding":"ABCA1 directly associates with syntaxin 13 (but not syntaxins 3 or 6) and flotillin-1, as demonstrated by immunoprecipitation. This complex resides in Lubrol WX-insoluble lipid raft microdomains and in phagosomes. siRNA silencing of syntaxin 13 reduced ABCA1 protein levels and significantly decreased apoA-I-dependent phospholipid efflux. Tangier fibroblasts with mutated ABCA1 showed enhanced phagocytosis that was normalized by re-expression of functional ABCA1.","method":"Co-immunoprecipitation, siRNA knockdown, immunofluorescence microscopy, detergent-resistant membrane fractionation, phagocytosis assay, lipid efflux assay","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 — reciprocal co-IP plus siRNA functional validation and genetic controls","pmids":["15469992"],"is_preprint":false},{"year":2005,"finding":"Unsaturated fatty acids destabilize ABCA1 through a phospholipase D2 (PLD2) signaling pathway. Long-chain acyl-CoA synthetase inhibitor triacsin C reversed this effect. PLD2 siRNA abolished unsaturated fatty acid-induced reduction in ABCA1 levels, increased serine phosphorylation of ABCA1, and inhibition of lipid transport activity. Diacylglycerol analogs also increased ABCA1 serine phosphorylation, implicating PLD2-generated diacylglycerols in destabilizing ABCA1 phosphorylation.","method":"siRNA knockdown of PLD2, pharmacological inhibitors (triacsin C, 1-butanol), phosphorylation assay, ABCA1 protein stability assay, lipid efflux assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — siRNA plus pharmacological validation with mechanistic phosphorylation readout","pmids":["16118212"],"is_preprint":false},{"year":2006,"finding":"Purified human ABCA1 reconstituted into liposomes exhibits robust ATPase activity. ATPase activity is stimulated preferentially by phospholipids with choline head groups (phosphatidylcholine and sphingomyelin) and inhibited by addition of cholesterol (25% decrease at 20% cholesterol). Beta-sitosterol and campesterol showed similar inhibitory effects but stigmasterol did not, indicating structure-specific sterol interactions. Glibenclamide suppressed ABCA1 ATPase activity, providing a biochemical basis for its inhibition of cholesterol efflux.","method":"Protein purification from Sf9 insect cells, liposome reconstitution, ATPase activity assay, trypsin limited-digestion conformational analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — in vitro reconstitution with purified protein, direct enzymatic assay","pmids":["16500904"],"is_preprint":false},{"year":2007,"finding":"ABCA1 mediates the mechanism of nascent HDL formation: binding of a small pool of apoA-I to ABCA1 enhances net phospholipid translocation to the plasma membrane exofacial leaflet, creating membrane strain relieved by formation of exovesiculated lipid domains. ApoA-I then binds at high affinity to these curved membrane domains and spontaneously solubilizes them to create discoidal nascent HDL particles containing 2–4 apoA-I molecules.","method":"Cell-based lipid efflux assay, apoA-I binding kinetics, analysis of HDL particle composition and size, phospholipid translocation assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — systematic mechanistic dissection with multiple complementary biochemical assays","pmids":["17604270"],"is_preprint":false},{"year":2007,"finding":"Beta-cell-specific inactivation of Abca1 in mice causes markedly impaired glucose tolerance and defective insulin secretion with normal insulin sensitivity. Isolated islets from these mice show altered cholesterol homeostasis and impaired insulin secretion in vitro. Rosiglitazone (a PPARγ activator that upregulates Abca1 in beta-cells) requires beta-cell Abca1 for its beneficial effects on glucose tolerance, establishing a role for ABCA1 in beta-cell cholesterol homeostasis and insulin secretion.","method":"Conditional beta-cell-specific knockout mice, glucose tolerance tests, insulin secretion assay, ex vivo islet cholesterol measurement","journal":"Nature medicine","confidence":"High","confidence_rationale":"Tier 2 — cell-type-specific KO with defined phenotype, pharmacological rescue experiment","pmids":["17322896"],"is_preprint":false},{"year":2008,"finding":"ABCA1 and apoA-I undergo endocytosis via a clathrin- and Rab5-mediated pathway and are recycled back to the cell surface via a Rab4-mediated route. Approximately 30% of endocytosed ABCA1 is recycled to the cell surface. When receptor-mediated endocytosis is inhibited, apoA-I internalization is blocked and cholesterol efflux from cells with excess lipoprotein-derived cholesterol decreases, while efflux from cells without excess cholesterol increases, indicating that retroendocytosis contributes to HDL formation particularly when excess cholesterol has accumulated.","method":"Extracellular HA-tagged and intracellular GFP-tagged ABCA1 constructs, clathrin inhibition, dominant-negative Rab protein expression, cholesterol efflux assay","journal":"Genes to cells","confidence":"High","confidence_rationale":"Tier 2 — engineered tagged constructs with pathway-specific inhibitors and functional efflux readout","pmids":["19170766"],"is_preprint":false},{"year":2008,"finding":"OSBP (oxysterol-binding protein) negatively regulates ABCA1 protein stability. OSBP knockdown increased ABCA1 protein half-life by 3-fold without affecting ABCA1 mRNA or LXR transcriptional activity. A mutation in the OSBP sterol-binding domain (but not mutations abrogating Golgi or ER interactions) prevented OSBP-mediated reduction of ABCA1, indicating that OSBP destabilizes ABCA1 via its sterol-binding domain.","method":"siRNA knockdown, ABCA1 protein half-life (cycloheximide chase), LXR reporter assay, OSBP domain mutants, cholesterol efflux assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — siRNA plus domain-specific mutagenesis with protein stability readout","pmids":["18450749"],"is_preprint":false},{"year":2009,"finding":"LRP1 deficiency leads to increased PDGFRβ signaling and sequential MAPK activation, which increases phosphorylation of cytosolic phospholipase A2 (cPLA2). Activated cPLA2 releases arachidonic acid, which suppresses LXR/RXR heterodimer activation at the ABCA1 promoter, resulting in greatly reduced ABCA1 expression. Thus LRP1 regulates ABCA1 expression and reverse cholesterol transport by controlling cPLA2 activation.","method":"LRP1 knockout cell lines, signaling pathway inhibitors, cPLA2 phosphorylation assay, ABCA1 promoter reporter, cholesterol efflux assay","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 — genetic KO with signaling pathway analysis, but single study","pmids":["19718435"],"is_preprint":false},{"year":2009,"finding":"ABCA1 and ABCG1 modulate macrophage inflammatory cytokine and chemokine expression by controlling sterol efflux and cellular membrane sterol levels. Transporter deficiency causes increased signaling via Toll-like receptors including TLR4, mechanistically linking cholesterol efflux activity to anti-inflammatory and immunosuppressive functions.","method":"ABCA1/ABCG1 knockout macrophages, cytokine/chemokine expression assays, TLR signaling pathway analysis","journal":"Arteriosclerosis, thrombosis, and vascular biology","confidence":"Medium","confidence_rationale":"Tier 2-3 — genetic KO phenotype but pathway placement partly inferential","pmids":["19797709"],"is_preprint":false},{"year":2011,"finding":"ABCA1 protein is degraded by calpain in early endosomes after endocytosis. When HDL biogenesis is ongoing (helical apolipoproteins interacting with ABCA1), ABCA1 becomes resistant to calpain and is recycled to the cell surface. Factors that interact with ABCA1 (α1-syntrophin, LXRβ, calmodulin) retard this calpain-mediated degradation. Pharmacological inhibition of calpain increases ABCA1 activity and HDL biogenesis in vitro and in vivo.","method":"Calpain inhibitors, subcellular fractionation, ABCA1 protein stability assay, endocytosis tracking, in vivo pharmacology","journal":"Biochimica et biophysica acta","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal approaches including in vivo validation, replicated across studies","pmids":["21835264"],"is_preprint":false},{"year":2011,"finding":"ApoA-I/ABCA1 interaction activates multiple downstream signaling pathways including JAK2/STAT3, protein kinase A, Rho GTPase CDC42, and protein kinase C. PKA and CDC42 activation regulates ABCA1-mediated lipid efflux, PKC activation stabilizes ABCA1 protein, and JAK2/STAT3 activation regulates both lipid efflux and anti-inflammatory effects, demonstrating that ABCA1 functions both as a lipid transporter and a signaling receptor.","method":"Kinase inhibitors, dominant-negative constructs, phosphorylation assays, cholesterol efflux assay, cytokine production assay","journal":"Biochimica et biophysica acta","confidence":"Medium","confidence_rationale":"Tier 3 — review integrating multiple published findings, individual pathway studies with moderate rigor","pmids":["21920460"],"is_preprint":false},{"year":2012,"finding":"miR-33a overexpression in human and mouse islets reduces ABCA1 expression, decreases glucose-stimulated insulin secretion, and increases cholesterol levels. The miR-33a-induced reduction in insulin secretion was rescued by cholesterol depletion (methyl-β-cyclodextrin or mevastatin), confirming that miR-33a suppresses insulin secretion through ABCA1-dependent islet cholesterol accumulation.","method":"Adenoviral miR-33a overexpression, miR-33a inhibition in ApoE-KO islets, ABCA1 overexpression rescue, cholesterol measurement, glucose-stimulated insulin secretion assay","journal":"Diabetes","confidence":"High","confidence_rationale":"Tier 2 — gain and loss of function with multiple rescue experiments confirming ABCA1-cholesterol-insulin axis","pmids":["22315319"],"is_preprint":false},{"year":2015,"finding":"Apoptotic cells trigger a BAI1→ELMO1→Rac1 signaling pathway that rapidly upregulates ABCA1 mRNA and protein, independently of the LXR sterol-sensing pathway. Primary macrophages from BAI1-, ELMO1-, or Rac1-deficient mice showed attenuated ABCA1 induction. BAI1 overexpression increased ABCA1 induction in response to apoptotic cells, and BAI1-deficient mice on high-fat diet had increased apoptotic cells in aortic roots with altered lipid profiles.","method":"Primary macrophages from BAI1/ELMO1/Rac1 KO mice, ABCA1 mRNA/protein induction assay, transgenic BAI1 overexpression, high-fat diet in vivo model","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 — multiple genetic KO models plus in vivo validation with defined pathway","pmids":["26075824"],"is_preprint":false},{"year":2016,"finding":"AMPK activation (pharmacological or genetic) increases ABCA1 and LXRα mRNA and protein in human macrophages, resulting in increased cholesterol efflux. Silencing LXRα (but not LXRβ) attenuated ABCA1 expression after AMPK activation. ChIP showed LXRα binding to the LXR responsive element in the ABCA1 promoter upon AMPK activation, placing AMPK upstream of LXRα in the regulatory pathway.","method":"AMPK siRNA/overexpression, pharmacological AMPK activators, LXRα siRNA, luciferase reporter assay, ChIP, cholesterol efflux assay","journal":"The international journal of biochemistry & cell biology","confidence":"High","confidence_rationale":"Tier 2 — genetic and pharmacological interventions with ChIP confirmation of promoter binding","pmids":["27343431"],"is_preprint":false},{"year":2017,"finding":"TRAK2 knockdown significantly increases cholesterol efflux and ABCA1 mRNA and protein expression. TRAK2 effect on cholesterol efflux was abolished in the absence of ABCA1, confirming ABCA1 dependency. ChIP showed that TRAK2 knockdown increases LXR binding at the ABCA1 promoter, establishing TRAK2 as a novel negative regulator of LXR-mediated ABCA1 transcription.","method":"siRNA knockdown (TRAK2 and ABCA1), ChIP, cholesterol efflux assay, mRNA/protein expression, human genetic-transcriptomic data correlation","journal":"European heart journal","confidence":"High","confidence_rationale":"Tier 2 — siRNA knockdown with ChIP and ABCA1-dependency rescue experiment","pmids":["28655204"],"is_preprint":false},{"year":2017,"finding":"Hepatocyte-specific ABCA1 knockout reduces plasma membrane free cholesterol content and impairs trafficking of lysosomal free cholesterol to the plasma membrane. This leads to reduced insulin-stimulated Akt phosphorylation, reduced SREBP-1c activation, and suppressed lipogenic gene expression, demonstrating that ABCA1 maintains hepatocyte plasma membrane cholesterol for efficient insulin signaling and lipogenesis.","method":"Hepatocyte-specific ABCA1 knockout mice, plasma membrane cholesterol fractionation, insulin signaling assays (Akt phosphorylation), SREBP-1c activation, glucose/insulin tolerance tests","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 — cell-type-specific KO with mechanistic dissection of PM cholesterol and signaling","pmids":["28591582"],"is_preprint":false},{"year":2019,"finding":"ApoE4 promotes greater expression of ARF6 compared with ApoE3, trapping ABCA1 in late endosomes and impairing its recycling to the cell membrane. This results in lower ABCA1-mediated cholesterol efflux, a greater percentage of lipid-free ApoE particles, and lower Aβ degradation capacity. Enhancing ABCA1 activity rescued impaired Aβ degradation in ApoE4-treated cells and reduced ApoE and ABCA1 aggregation in the hippocampus of ApoE4 knock-in mice.","method":"ARF6 expression analysis, ABCA1 trafficking assay (late endosome trapping), cholesterol efflux assay, ApoE lipidation assay, Aβ degradation assay, in vivo ApoE4-targeted replacement mice","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — mechanistic cell biology with in vivo validation in knock-in model","pmids":["31641056"],"is_preprint":false},{"year":2019,"finding":"PMP22 (peripheral myelin protein 22) physically interacts with ABCA1 at the Schwann cell plasma membrane (demonstrated by co-immunoprecipitation). Absence of PMP22 results in reduced ABCA1 localization to the cell membrane and diminished apoE secretion and ABCA1-mediated cholesterol efflux, despite upregulation of ABCA1 and apoE mRNA/protein. Conversely, ABCA1 knockout elevates PMP22 expression and aberrant processing.","method":"Co-immunoprecipitation from Schwann cell and nerve lysates, immunofluorescence co-localization, ABCA1 KO mice, PMP22 KO mice, cholesterol efflux assay, whole-cell patch clamp","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — reciprocal co-IP with genetic KO models and functional efflux validation","pmids":["31061090"],"is_preprint":false},{"year":2006,"finding":"ABCA1 deficiency in the brain of ABCA1 knockout mice causes a considerable decrease in soluble brain apoE protein levels and increases amyloid deposition in APP23 transgenic mice, including increased parenchymal and vascular (cerebral amyloid angiopathy) amyloid. The results establish ABCA1 as a regulator of apoE lipidation/solubility in brain and a modifier of amyloid pathology.","method":"ABCA1 knockout crossed with APP23 transgenic mice, Aβ immunoreactivity, thioflavine S staining, cerebral amyloid angiopathy assessment, apoE protein quantification (soluble vs insoluble fractions)","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — genetic KO in disease model with multiple amyloid and apoE readouts","pmids":["16207713"],"is_preprint":false},{"year":2006,"finding":"HIV-1 Nef protein binds ABCA1 and impairs ABCA1-dependent cholesterol efflux from macrophages through two mechanisms: post-transcriptional downregulation of ABCA1 and redistribution of ABCA1 to the plasma membrane with inhibited apoA-I internalization. This causes lipid accumulation in HIV-infected macrophages resembling foam cells. Stimulation of cholesterol efflux reduced HIV virion infectivity by decreasing virion-associated cholesterol.","method":"Nef transfection in murine macrophages, ABCA1 protein expression analysis, ABCA1 trafficking (redistribution assay), co-immunoprecipitation (Nef-ABCA1 binding), cholesterol efflux assay, virion cholesterol measurement","journal":"PLoS biology","confidence":"High","confidence_rationale":"Tier 2 — direct Nef-ABCA1 binding plus multiple functional assays with mechanistic dissection","pmids":["17076584"],"is_preprint":false},{"year":2009,"finding":"HIF-1β availability determines ABCA1 expression and cholesterol efflux in macrophages under hypoxia. HIF-1 complex specifically binds to the HIF-1 response element in the ABCA1 promoter and increases ABCA1 promoter activity. ABCA1 expression and cholesterol efflux strongly correlated with HIF-1β expression in hypoxic macrophages and in human atherosclerotic lesion macrophages.","method":"HIF-1 response element binding assay, ABCA1 promoter-reporter assay, constitutively active HIF-1α overexpression, ChIP (inferred), cholesterol efflux under hypoxia, human atherosclerotic lesion analysis","journal":"The international journal of biochemistry & cell biology","confidence":"Medium","confidence_rationale":"Tier 2-3 — promoter binding and gain-of-function with in vivo correlation, single study","pmids":["19828131"],"is_preprint":false},{"year":2019,"finding":"CXCL12 reduces ABCA1 expression and cholesterol efflux from macrophages via CXCR4→GSK3β phosphorylation→β-catenin Thr120 phosphorylation pathway. TCF21 directly stimulates ABCA1 transcription by binding to its promoter (confirmed by luciferase reporter and ChIP), and CXCL12 represses TCF21. Knockdown or inhibition of CXCR4 blocked CXCL12 effects on TCF21 and ABCA1 expression.","method":"Luciferase reporter assay, ChIP, siRNA knockdown (CXCR4), kinase inhibitors, protein phosphorylation assays, cholesterol efflux assay, in vivo lentiviral CXCL12 overexpression in Apoe-/- mice","journal":"Journal of lipid research","confidence":"High","confidence_rationale":"Tier 2 — ChIP plus reporter assay plus siRNA with in vivo confirmation","pmids":["31662443"],"is_preprint":false},{"year":2020,"finding":"ABCA1 regulates aqueous humor outflow and intraocular pressure via the caveolin-1/endothelial NO synthase (eNOS)/NO signaling pathway. ABCA1 upregulation in angular aqueous plexus (Schlemm's canal equivalent) cells decreases caveolin-1 expression and increases eNOS expression and NO production, reducing transendothelial resistance. In vivo intracameral injection of ABCA1 agonist GW3965 decreased IOP and increased conventional outflow facility.","method":"ABCA1 overexpression (lentivirus-ABCA1-shRNA or agonist GW3965), transendothelial electrical resistance measurement, eNOS/caveolin-1 protein expression, NO concentration measurement, in vivo intracameral injection, IOP measurement","journal":"Investigative ophthalmology & visual science","confidence":"Medium","confidence_rationale":"Tier 2 — gain and loss of function in cell model with in vivo confirmation, single study","pmids":["32428234"],"is_preprint":false},{"year":2017,"finding":"ABCA1 mediates microparticle (MP) formation during HDL biogenesis. Using ABCA1 overexpression under inducible control and selective ABCA1 inactivation (probucol), MPs were shown to constitute approximately 30% of ABCA1-and apoA-I-mediated cholesterol efflux. Adding apoA-I markedly increases MP release. MPs contain flotillin-2 and CD63 but not apoA-I.","method":"Inducible ABCA1 expression system, probucol-mediated ABCA1 inhibition, methyl-β-cyclodextrin cholesterol depletion, MP characterization (size, markers), cholesterol efflux assay","journal":"Atherosclerosis","confidence":"Medium","confidence_rationale":"Tier 2 — inducible expression plus pharmacological inhibition in multiple cell types, single lab","pmids":["28129550"],"is_preprint":false},{"year":2025,"finding":"Caveolin-1 acts as a key promoter of ABCA1 endolysosomal trafficking identified by discovery proteomics. In APOE4 and AD models, greater caveolin-1 expression traps ABCA1 in lysosomes, causing oxysterol accumulation, mTORC1 activation, and cellular senescence. Cyclodextrin treatment reduced brain oxysterol levels, ABCA1 lysosome trapping, mTORC1 activation, and senescence markers in APOE4-TR mice.","method":"Unbiased proteomics (discovery), ABCA1 knockout cell lines and mouse models, APOE4-TR mice, iPSC-derived astrocytes, mTORC1 phosphorylation assay, senescence markers, cyclodextrin treatment","journal":"Molecular neurodegeneration","confidence":"Medium","confidence_rationale":"Tier 2 — proteomics discovery with genetic and pharmacological validation in multiple models, single recent study","pmids":["39901180"],"is_preprint":false}],"current_model":"ABCA1 is an ATP-hydrolyzing transmembrane flippase that translocates phospholipids from the cytoplasmic to the exofacial leaflet of the plasma membrane, creating membrane strain and exovesiculated lipid domains to which lipid-free apoA-I binds directly (via interaction with ABCA1 and membrane lipid domains) and solubilizes phospholipid and cholesterol to assemble nascent discoidal HDL particles; its expression is transcriptionally induced by LXR/RXR, RAR/RXR, HIF-1, and AMPK→LXRα pathways via DR4 and other promoter elements, while post-translationally ABCA1 protein stability is regulated by calpain-mediated degradation in early endosomes (retarded by apoA-I binding, α1-syntrophin, calmodulin, and LXRβ), by PLD2/diacylglycerol-dependent serine phosphorylation (triggered by unsaturated fatty acids), by cAMP/PKA-dependent phosphorylation (enhancing efflux), by OSBP sterol-binding domain-dependent destabilization, and by ARF6-dependent endolysosomal trapping; ABCA1 also functions as a signaling receptor activating JAK2/STAT3, PKA, PKC, and CDC42 pathways upon apoA-I binding, mediates phosphatidylserine exposure and microparticle formation, regulates beta-cell insulin secretion and hepatocyte insulin signaling through plasma membrane free cholesterol maintenance, and modulates neuroinflammation and apoE lipidation in the brain."},"narrative":{"teleology":[{"year":1999,"claim":"Identification of ABCA1 as the gene mutated in Tangier disease and familial HDL deficiency resolved a decades-old question about the molecular basis of apolipoprotein-mediated cholesterol efflux and HDL formation.","evidence":"Gene expression microarrays, genetic mapping, mutation sequencing in patient fibroblasts, and functional validation via siRNA/overexpression across multiple independent labs","pmids":["10525055","10431236","10431237","10431238","10533863","10535983"],"confidence":"High","gaps":["Mechanism by which ABCA1 moves lipids was unknown","Direct protein–apoA-I interaction not yet shown","Transcriptional regulation undefined"]},{"year":2000,"claim":"Demonstration that apoA-I binds directly to ABCA1 at the cell surface and that ABCA1 expression induces phospholipid translocation and phosphatidylserine exposure established it as a lipid flippase generating exofacial membrane strain.","evidence":"Chemical cross-linking, co-immunoprecipitation, echinocyte morphology in ABCA1-overexpressing cells, prothrombinase assay and spin-labeled phospholipid transbilayer redistribution in knockout and transfected cells","pmids":["10918065","10878804"],"confidence":"High","gaps":["No purified-protein ATPase data yet","Structural basis of apoA-I–ABCA1 interaction unknown","Whether flippase activity is sufficient for HDL assembly unresolved"]},{"year":2000,"claim":"Discovery that LXR/RXR heterodimers directly activate the ABCA1 promoter via a DR4 element established the sterol-sensing transcriptional circuit controlling reverse cholesterol transport.","evidence":"Promoter-reporter assays with site-directed mutagenesis of DR4 element, LXR/RXR co-transfection, rexinoid pharmacology in mice","pmids":["10858438","10968783"],"confidence":"High","gaps":["Other transcription factors acting on ABCA1 promoter unknown","Post-transcriptional regulation not addressed"]},{"year":2002,"claim":"Identification of cAMP/PKA-dependent phosphorylation of ABCA1 as an activating signal for cholesterol efflux revealed a rapid post-translational regulatory mechanism distinct from transcriptional control.","evidence":"Radiolabeled phosphorylation assay with PKA inhibitor H-89 and genetic controls from Tangier disease and familial HDL deficiency fibroblasts","pmids":["12454270"],"confidence":"High","gaps":["Specific phosphorylation sites on ABCA1 not mapped","Kinase-phosphatase balance not characterized"]},{"year":2003,"claim":"RAR/RXR was shown to directly activate ABCA1 via the same DR4 element as LXR/RXR, expanding the regulatory network to include retinoid signaling and demonstrating receptor redundancy at this promoter element.","evidence":"ChIP in macrophages, RARγ-knockout mouse macrophages showing compensatory RARα induction","pmids":["14560020"],"confidence":"High","gaps":["Physiological contexts where RAR dominates over LXR unclear","Combinatorial versus competitive binding not resolved"]},{"year":2004,"claim":"Identification of syntaxin 13 and flotillin-1 as direct ABCA1 interaction partners in lipid raft microdomains established that ABCA1 operates within a defined membrane trafficking complex, and probucol was shown to block ABCA1 translocation to the plasma membrane.","evidence":"Reciprocal co-immunoprecipitation, siRNA knockdown of syntaxin 13 reducing ABCA1 levels and efflux, probucol trafficking assays with Tangier fibroblast controls","pmids":["15469992","15514211"],"confidence":"High","gaps":["How syntaxin 13 controls ABCA1 stability versus trafficking not distinguished","Probucol's direct molecular target on ABCA1 not identified"]},{"year":2005,"claim":"Unsaturated fatty acids were shown to destabilize ABCA1 through PLD2-generated diacylglycerol and serine phosphorylation, revealing a lipid-sensing post-translational degradation pathway.","evidence":"PLD2 siRNA rescue, triacsin C inhibitor, diacylglycerol analog experiments with phosphorylation and protein stability readouts","pmids":["16118212"],"confidence":"High","gaps":["Specific serine residues targeted not identified","Whether PLD2 pathway operates in vivo not tested"]},{"year":2006,"claim":"Reconstitution of purified ABCA1 into liposomes provided direct biochemical proof of intrinsic ATPase activity stimulated by phospholipids and inhibited by cholesterol, confirming the flippase hypothesis at the protein level.","evidence":"Purified human ABCA1 from Sf9 cells, liposome ATPase assay with defined lipid compositions","pmids":["16500904"],"confidence":"High","gaps":["No direct lipid translocation demonstrated with purified protein","Structure of ABCA1 not solved"]},{"year":2006,"claim":"Brain ABCA1 deficiency was shown to reduce soluble apoE and increase amyloid deposition in APP transgenic mice, and HIV-1 Nef was found to bind and impair ABCA1, establishing disease-relevant consequences of ABCA1 dysfunction beyond HDL metabolism.","evidence":"ABCA1-KO × APP23 crosses with amyloid staining and apoE fractionation; Nef–ABCA1 co-IP with efflux and virion cholesterol assays","pmids":["16207713","17076584"],"confidence":"High","gaps":["Whether ABCA1 effects on amyloid are solely via apoE lipidation not resolved","In vivo relevance of Nef–ABCA1 interaction in HIV patients not confirmed"]},{"year":2007,"claim":"A detailed mechanistic model of nascent HDL assembly was established: ABCA1-driven phospholipid translocation creates curved exovesiculated membrane domains from which apoA-I spontaneously solubilizes discoidal particles, and separately, β-cell-specific ABCA1 knockout revealed a role in insulin secretion via islet cholesterol homeostasis.","evidence":"Systematic lipid efflux kinetics and HDL particle composition analysis; conditional β-cell ABCA1 KO mice with glucose tolerance and insulin secretion assays","pmids":["17604270","17322896"],"confidence":"High","gaps":["Stoichiometry and kinetics of apoA-I–membrane domain interaction not fully defined","Whether β-cell phenotype is relevant to human diabetes from ABCA1 variants not established"]},{"year":2008,"claim":"ABCA1 endocytic recycling via clathrin/Rab5 internalization and Rab4 return was mapped, and OSBP was identified as a sterol-sensing negative regulator of ABCA1 protein stability, integrating trafficking and post-translational control.","evidence":"Tagged ABCA1 constructs with dominant-negative Rabs and clathrin inhibition; OSBP siRNA with cycloheximide chase and domain mutants","pmids":["19170766","18450749"],"confidence":"High","gaps":["How OSBP sterol binding leads to ABCA1 degradation mechanistically unclear","Relative contribution of recycling versus de novo synthesis to steady-state ABCA1 not quantified"]},{"year":2009,"claim":"Macrophage ABCA1 was linked to anti-inflammatory function through TLR signaling modulation, HIF-1 was identified as a direct transcriptional activator under hypoxia, and the LRP1→cPLA2→LXR pathway was shown to control ABCA1 expression, substantially expanding the upstream regulatory network.","evidence":"ABCA1/ABCG1-KO macrophages with TLR/cytokine readouts; HIF-1 response element binding and promoter assays; LRP1-KO cells with cPLA2 signaling analysis","pmids":["19797709","19828131","19718435"],"confidence":"Medium","gaps":["ABCA1-specific versus ABCG1-specific anti-inflammatory contributions not fully separated","HIF-1 regulation of ABCA1 not independently replicated","LRP1 pathway is single-study evidence"]},{"year":2011,"claim":"Calpain was identified as the protease responsible for ABCA1 degradation in early endosomes, with apoA-I binding and interactors (α1-syntrophin, LXRβ, calmodulin) protecting ABCA1 from calpain, and apoA-I/ABCA1 signaling via JAK2/STAT3, PKA, CDC42, and PKC was documented.","evidence":"Calpain inhibitor pharmacology with subcellular fractionation and in vivo validation; kinase inhibitors and dominant-negative constructs for signaling pathway dissection","pmids":["21835264","21920460"],"confidence":"High","gaps":["Calpain cleavage site on ABCA1 not mapped","Relative importance of individual signaling arms not established in vivo","JAK2/STAT3 pathway evidence largely compiled from multiple prior studies"]},{"year":2012,"claim":"miR-33a was shown to suppress ABCA1 expression in islets and reduce insulin secretion through cholesterol accumulation, providing a post-transcriptional regulatory axis linking metabolic microRNA networks to β-cell function.","evidence":"Adenoviral miR-33a overexpression and inhibition in human/mouse islets with cholesterol depletion rescue","pmids":["22315319"],"confidence":"High","gaps":["In vivo relevance of miR-33a–ABCA1 axis to type 2 diabetes not demonstrated","Other miR-33a targets that could contribute not excluded"]},{"year":2015,"claim":"A sterol-independent transcriptional induction pathway was discovered: apoptotic cells activate BAI1→ELMO1→Rac1 to upregulate ABCA1 independently of LXR, linking efferocytosis directly to cholesterol efflux capacity.","evidence":"Primary macrophages from BAI1/ELMO1/Rac1-KO mice, in vivo high-fat diet model with aortic root amyloid and lipid profiling","pmids":["26075824"],"confidence":"High","gaps":["Downstream transcription factor activated by Rac1 to drive ABCA1 not identified","Whether this pathway is relevant in non-macrophage cell types unknown"]},{"year":2016,"claim":"AMPK was placed upstream of LXRα in ABCA1 transcriptional activation, with ChIP confirming LXRα binding to the ABCA1 promoter upon AMPK activation, connecting energy-sensing to cholesterol efflux.","evidence":"AMPK siRNA/overexpression, LXRα siRNA epistasis, ChIP, pharmacological activators in human macrophages","pmids":["27343431"],"confidence":"High","gaps":["How AMPK activates LXRα (direct phosphorylation vs indirect) not resolved","In vivo relevance in atherosclerosis models not tested"]},{"year":2017,"claim":"TRAK2 was identified as a negative regulator of LXR-mediated ABCA1 transcription, hepatocyte ABCA1 was shown essential for maintaining plasma membrane cholesterol and insulin signaling, and ABCA1-dependent microparticle release was quantified as ~30% of total cholesterol efflux.","evidence":"TRAK2 siRNA with ChIP showing increased LXR promoter binding; hepatocyte-specific ABCA1-KO with Akt phosphorylation and SREBP-1c readouts; inducible ABCA1 expression with MP characterization","pmids":["28655204","28591582","28129550"],"confidence":"High","gaps":["Mechanism by which TRAK2 inhibits LXR promoter access unknown","Relative importance of MP release versus direct lipid transfer to apoA-I in vivo not established"]},{"year":2019,"claim":"ApoE4-driven ARF6 overexpression was shown to trap ABCA1 in late endosomes, impairing cholesterol efflux and Aβ degradation, and the CXCL12→CXCR4→GSK3β→β-catenin→TCF21 pathway was identified as a transcriptional repressor of ABCA1, while PMP22 was found to physically interact with ABCA1 and facilitate its plasma membrane localization in Schwann cells.","evidence":"ARF6 trafficking assays in ApoE4-TR mice; ChIP and reporter assays for TCF21/CXCL12 pathway with in vivo lentiviral overexpression; reciprocal co-IP from Schwann cell and nerve lysates with PMP22-KO and ABCA1-KO mice","pmids":["31641056","31662443","31061090"],"confidence":"High","gaps":["Whether ARF6-mediated trapping is reversible therapeutically not established","TCF21 as ABCA1 activator demonstrated only in macrophages","PMP22–ABCA1 interaction domain not mapped"]},{"year":2020,"claim":"ABCA1 was linked to intraocular pressure regulation through modulation of caveolin-1/eNOS/NO signaling in Schlemm's canal endothelium, extending its functional repertoire beyond lipid metabolism.","evidence":"Lentiviral ABCA1 manipulation, transendothelial resistance, eNOS/NO measurement, in vivo intracameral GW3965 injection with IOP measurement","pmids":["32428234"],"confidence":"Medium","gaps":["Single study without independent replication","Whether cholesterol efflux per se mediates eNOS derepression or a distinct ABCA1 mechanism operates is unclear"]},{"year":2025,"claim":"Caveolin-1 was identified by unbiased proteomics as a promoter of ABCA1 endolysosomal trapping, linking APOE4-associated ABCA1 mislocalization to oxysterol accumulation, mTORC1 activation, and cellular senescence.","evidence":"Discovery proteomics, ABCA1-KO cells and mice, APOE4-TR mice, iPSC-derived astrocytes, cyclodextrin rescue","pmids":["39901180"],"confidence":"Medium","gaps":["Single recent study awaiting independent replication","Whether caveolin-1 directly binds ABCA1 or acts indirectly through membrane domains not determined","Therapeutic relevance of cyclodextrin in humans unknown"]},{"year":null,"claim":"A high-resolution structure of full-length ABCA1 in complex with apoA-I and/or lipid substrates is needed to explain the molecular basis of phospholipid flippase selectivity, cholesterol inhibition, and the coupling between ATP hydrolysis and lipid translocation.","evidence":"","pmids":[],"confidence":"High","gaps":["No atomic-resolution structure of ABCA1 in lipid-bound or apoA-I-bound state","Direct lipid translocation has not been demonstrated with purified reconstituted protein","In vivo contributions of microparticle release versus direct apoA-I lipidation not quantified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140657","term_label":"ATP-dependent activity","supporting_discovery_ids":[11,12]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[2,11,12]},{"term_id":"GO:0005215","term_label":"transporter activity","supporting_discovery_ids":[0,1,3,11,12]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[19]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,2,8,12,14,26]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[14,18,25,33]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[14,32]}],"pathway":[{"term_id":"R-HSA-382551","term_label":"Transport of small molecules","supporting_discovery_ids":[0,1,2,11,12,13,24]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[4,5,11,13,20,24]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[6,19,22]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[17]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[8,14,18,25]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[4,7,22,23,30]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[1,27,28]}],"complexes":[],"partners":["APOA1","STX13","FLOT1","PMP22","OSBP","PLD2","CAV1"],"other_free_text":[]},"mechanistic_narrative":"ABCA1 is an ATP-hydrolyzing phospholipid flippase that translocates phospholipids from the inner to the outer leaflet of the plasma membrane, creating exovesiculated lipid domains to which lipid-free apoA-I binds and solubilizes phospholipid and cholesterol to assemble nascent discoidal HDL particles [PMID:17604270, PMID:10918065]. Its ATPase activity is stimulated by choline-containing phospholipids and inhibited by cholesterol [PMID:16500904], and the protein cycles between the plasma membrane and early endosomes via clathrin/Rab5-dependent endocytosis and Rab4-dependent recycling, with calpain-mediated degradation in endosomes serving as a major turnover mechanism retarded by apoA-I binding [PMID:19170766, PMID:21835264]. Transcription is driven by LXR/RXR and RAR/RXR heterodimers acting on a DR4 promoter element, with additional regulation by HIF-1, AMPK→LXRα, TCF21, and BAI1→ELMO1→Rac1 pathways, while post-translational stability is modulated by PLD2/diacylglycerol-dependent serine phosphorylation, OSBP sterol-binding-domain-dependent destabilization, and cAMP/PKA-dependent phosphorylation that enhances efflux [PMID:10858438, PMID:14560020, PMID:27343431, PMID:16118212, PMID:18450749, PMID:12454270]. Loss-of-function mutations in ABCA1 cause Tangier disease and familial HDL deficiency, and cell-type-specific deletion in pancreatic β-cells or hepatocytes disrupts cholesterol-dependent insulin secretion and insulin signaling, respectively, while brain ABCA1 deficiency reduces apoE lipidation and exacerbates amyloid deposition [PMID:10533863, PMID:17322896, PMID:28591582, PMID:16207713]."},"prefetch_data":{"uniprot":{"accession":"O95477","full_name":"Phospholipid-transporting ATPase ABCA1","aliases":["ATP-binding cassette sub-family A member 1","ATP-binding cassette transporter 1","ABC-1","ATP-binding cassette 1","Cholesterol efflux regulatory protein"],"length_aa":2261,"mass_kda":254.3,"function":"Catalyzes the translocation of specific phospholipids from the cytoplasmic to the extracellular/lumenal leaflet of membrane coupled to the hydrolysis of ATP (PubMed:24097981, PubMed:35974019). Thereby, participates in phospholipid transfer to apolipoproteins to form nascent high density lipoproteins/HDLs (PubMed:14754908). Transports preferentially phosphatidylcholine over phosphatidylserine (PubMed:24097981). May play a similar role in the efflux of intracellular cholesterol to apolipoproteins and the formation of nascent high density lipoproteins/HDLs (PubMed:10533863, PubMed:14754908, PubMed:24097981, PubMed:35974019). Translocates phospholipids from the outer face of the plasma membrane and forces it through its gateway and annulus into an elongated hydrophobic tunnel in its extracellular domain (PubMed:35974019)","subcellular_location":"Cell membrane; Endosome","url":"https://www.uniprot.org/uniprotkb/O95477/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ABCA1","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ABCA1","total_profiled":1310},"omim":[{"mim_id":"619836","title":"HYPOALPHALIPOPROTEINEMIA, PRIMARY, 2, INTERMEDIATE","url":"https://www.omim.org/entry/619836"},{"mim_id":"618649","title":"HECT DOMAIN E3 UBIQUITIN PROTEIN LIGASE 1; HECTD1","url":"https://www.omim.org/entry/618649"},{"mim_id":"618463","title":"HYPOALPHALIPOPROTEINEMIA, PRIMARY, 2","url":"https://www.omim.org/entry/618463"},{"mim_id":"613574","title":"TETRATRICOPEPTIDE REPEAT DOMAIN-CONTAINING PROTEIN 39B; TTC39B","url":"https://www.omim.org/entry/613574"},{"mim_id":"613486","title":"MICRO RNA 33B; MIR33B","url":"https://www.omim.org/entry/613486"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Plasma membrane","reliability":"Supported"},{"location":"Golgi apparatus","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/ABCA1"},"hgnc":{"alias_symbol":["TGD"],"prev_symbol":["ABC1","HDLDT1"]},"alphafold":{"accession":"O95477","domains":[{"cath_id":"-","chopping":"2-32_639-861","consensus_level":"medium","plddt":82.0266,"start":2,"end":861},{"cath_id":"-","chopping":"52-112_281-336_354-413_506-628_1540-1641","consensus_level":"medium","plddt":75.1429,"start":52,"end":1641},{"cath_id":"-","chopping":"122-277","consensus_level":"medium","plddt":65.6803,"start":122,"end":277},{"cath_id":"-","chopping":"414-504","consensus_level":"medium","plddt":67.9588,"start":414,"end":504},{"cath_id":"3.40.50.300","chopping":"895-1114","consensus_level":"high","plddt":82.1258,"start":895,"end":1114},{"cath_id":"3.30.70.250","chopping":"1125-1134_1180-1242","consensus_level":"medium","plddt":77.0812,"start":1125,"end":1242}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O95477","model_url":"https://alphafold.ebi.ac.uk/files/AF-O95477-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O95477-F1-predicted_aligned_error_v6.png","plddt_mean":73.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ABCA1","jax_strain_url":"https://www.jax.org/strain/search?query=ABCA1"},"sequence":{"accession":"O95477","fasta_url":"https://rest.uniprot.org/uniprotkb/O95477.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O95477/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O95477"}},"corpus_meta":[{"pmid":"10968783","id":"PMC_10968783","title":"Regulation of absorption and ABC1-mediated efflux of cholesterol by RXR heterodimers.","date":"2000","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/10968783","citation_count":1101,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10858438","id":"PMC_10858438","title":"Sterol-dependent transactivation of the ABC1 promoter by the liver X receptor/retinoid X receptor.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10858438","citation_count":828,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10525055","id":"PMC_10525055","title":"The Tangier disease gene product ABC1 controls the cellular apolipoprotein-mediated lipid removal pathway.","date":"1999","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/10525055","citation_count":594,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"19797709","id":"PMC_19797709","title":"Role of HDL, ABCA1, and ABCG1 transporters in cholesterol efflux and immune responses.","date":"2009","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/19797709","citation_count":557,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10918065","id":"PMC_10918065","title":"Specific binding of ApoA-I, enhanced cholesterol efflux, and altered plasma membrane morphology in cells expressing ABC1.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10918065","citation_count":502,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10878804","id":"PMC_10878804","title":"ABC1 promotes engulfment of apoptotic cells and transbilayer redistribution of phosphatidylserine.","date":"2000","source":"Nature cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/10878804","citation_count":437,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"17322896","id":"PMC_17322896","title":"Beta-cell ABCA1 influences insulin secretion, glucose homeostasis and response to thiazolidinedione treatment.","date":"2007","source":"Nature medicine","url":"https://pubmed.ncbi.nlm.nih.gov/17322896","citation_count":346,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16501936","id":"PMC_16501936","title":"Role of apoA-I, ABCA1, LCAT, and SR-BI in the biogenesis of HDL.","date":"2006","source":"Journal of molecular medicine (Berlin, Germany)","url":"https://pubmed.ncbi.nlm.nih.gov/16501936","citation_count":297,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10533863","id":"PMC_10533863","title":"Mutations in the ABC1 gene in familial HDL deficiency with defective cholesterol efflux.","date":"1999","source":"Lancet (London, England)","url":"https://pubmed.ncbi.nlm.nih.gov/10533863","citation_count":289,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10882340","id":"PMC_10882340","title":"ABCA1-mediated transport of cellular cholesterol and phospholipids to HDL apolipoproteins.","date":"2000","source":"Current opinion in lipidology","url":"https://pubmed.ncbi.nlm.nih.gov/10882340","citation_count":234,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10535983","id":"PMC_10535983","title":"Human ATP-binding cassette transporter 1 (ABC1): genomic organization and identification of the genetic defect in the original Tangier disease kindred.","date":"1999","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/10535983","citation_count":216,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12615680","id":"PMC_12615680","title":"HDL apolipoproteins and ABCA1: partners in the removal of excess cellular cholesterol.","date":"2003","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/12615680","citation_count":199,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11111099","id":"PMC_11111099","title":"Tangier disease and ABCA1.","date":"2000","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/11111099","citation_count":183,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11264984","id":"PMC_11264984","title":"Structure, function and regulation of the ABC1 gene product.","date":"2001","source":"Current opinion in lipidology","url":"https://pubmed.ncbi.nlm.nih.gov/11264984","citation_count":174,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15922656","id":"PMC_15922656","title":"Transcriptional regulatory networks in lipid metabolism control ABCA1 expression.","date":"2005","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/15922656","citation_count":172,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15632021","id":"PMC_15632021","title":"ABCA1 gene deletion protects against cerebral malaria: potential pathogenic role of microparticles in neuropathology.","date":"2005","source":"The American journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/15632021","citation_count":145,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"29305383","id":"PMC_29305383","title":"Is ABCA1 a lipid transfer protein?","date":"2018","source":"Journal of lipid research","url":"https://pubmed.ncbi.nlm.nih.gov/29305383","citation_count":139,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15514211","id":"PMC_15514211","title":"Probucol inhibits ABCA1-mediated cellular lipid efflux.","date":"2004","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/15514211","citation_count":127,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"33562440","id":"PMC_33562440","title":"The Role of the ATP-Binding Cassette A1 (ABCA1) in Human Disease.","date":"2021","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/33562440","citation_count":125,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"31641056","id":"PMC_31641056","title":"ApoE4 Alters ABCA1 Membrane Trafficking in Astrocytes.","date":"2019","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/31641056","citation_count":120,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"22315319","id":"PMC_22315319","title":"miR-33a modulates ABCA1 expression, cholesterol accumulation, and insulin secretion in pancreatic islets.","date":"2012","source":"Diabetes","url":"https://pubmed.ncbi.nlm.nih.gov/22315319","citation_count":119,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"31524223","id":"PMC_31524223","title":"Quercetin protects against atherosclerosis by regulating the expression of PCSK9, CD36, PPARγ, LXRα and ABCA1.","date":"2019","source":"International journal of molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/31524223","citation_count":118,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"25359426","id":"PMC_25359426","title":"ABCA1 and nascent HDL biogenesis.","date":"2014","source":"BioFactors (Oxford, England)","url":"https://pubmed.ncbi.nlm.nih.gov/25359426","citation_count":117,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11518753","id":"PMC_11518753","title":"Regulation and intracellular trafficking of the ABCA1 transporter.","date":"2001","source":"Journal of lipid research","url":"https://pubmed.ncbi.nlm.nih.gov/11518753","citation_count":114,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"31831519","id":"PMC_31831519","title":"Brothers in Arms: ABCA1- and ABCG1-Mediated Cholesterol Efflux as Promising Targets in Cardiovascular Disease Treatment.","date":"2020","source":"Pharmacological reviews","url":"https://pubmed.ncbi.nlm.nih.gov/31831519","citation_count":108,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"14560020","id":"PMC_14560020","title":"Retinoic acid receptor-mediated induction of ABCA1 in macrophages.","date":"2003","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/14560020","citation_count":108,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"35192423","id":"PMC_35192423","title":"Molecular mechanisms for ABCA1-mediated cholesterol efflux.","date":"2022","source":"Cell cycle (Georgetown, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/35192423","citation_count":102,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12454270","id":"PMC_12454270","title":"cAMP induces ABCA1 phosphorylation activity and promotes cholesterol efflux from fibroblasts.","date":"2002","source":"Journal of lipid research","url":"https://pubmed.ncbi.nlm.nih.gov/12454270","citation_count":102,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"26075824","id":"PMC_26075824","title":"Apoptotic cells trigger a membrane-initiated pathway to increase ABCA1.","date":"2015","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/26075824","citation_count":101,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11231917","id":"PMC_11231917","title":"Localization of human ATP-binding cassette transporter 1 (ABC1) in normal and atherosclerotic tissues.","date":"2001","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/11231917","citation_count":97,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"19344785","id":"PMC_19344785","title":"The cell cholesterol exporter ABCA1 as a protector from cardiovascular disease and diabetes.","date":"2009","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/19344785","citation_count":96,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"27567858","id":"PMC_27567858","title":"ABCA1 Agonist Reverses the ApoE4-Driven Cognitive and Brain Pathologies.","date":"2016","source":"Journal of Alzheimer's disease : JAD","url":"https://pubmed.ncbi.nlm.nih.gov/27567858","citation_count":96,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"22064972","id":"PMC_22064972","title":"The interaction of ApoA-I and ABCA1 triggers signal transduction pathways to mediate efflux of cellular lipids.","date":"2012","source":"Molecular medicine (Cambridge, Mass.)","url":"https://pubmed.ncbi.nlm.nih.gov/22064972","citation_count":92,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16500904","id":"PMC_16500904","title":"Purification and ATPase activity of human ABCA1.","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16500904","citation_count":91,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12615681","id":"PMC_12615681","title":"Study of ABCA1 function in transgenic mice.","date":"2003","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/12615681","citation_count":90,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16118212","id":"PMC_16118212","title":"Unsaturated fatty acids phosphorylate and destabilize ABCA1 through a phospholipase D2 pathway.","date":"2005","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16118212","citation_count":86,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16381920","id":"PMC_16381920","title":"Tetrahymena Genome Database (TGD): a new genomic resource for Tetrahymena thermophila research.","date":"2006","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/16381920","citation_count":82,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"23376685","id":"PMC_23376685","title":"ABCA1 influences neuroinflammation and neuronal death.","date":"2013","source":"Neurobiology of disease","url":"https://pubmed.ncbi.nlm.nih.gov/23376685","citation_count":81,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16013195","id":"PMC_16013195","title":"ABCA1 and atherosclerosis.","date":"2005","source":"Vascular medicine (London, England)","url":"https://pubmed.ncbi.nlm.nih.gov/16013195","citation_count":78,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"21920460","id":"PMC_21920460","title":"Regulation of ABCA1 functions by signaling pathways.","date":"2011","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/21920460","citation_count":77,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"17936760","id":"PMC_17936760","title":"Adiponectin deficiency suppresses ABCA1 expression and ApoA-I synthesis in the liver.","date":"2007","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/17936760","citation_count":74,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15358117","id":"PMC_15358117","title":"Serum amyloid A promotes ABCA1-dependent and ABCA1-independent lipid efflux from cells.","date":"2004","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/15358117","citation_count":73,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11279093","id":"PMC_11279093","title":"Regulation and activity of the human ABCA1 gene in transgenic mice.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11279093","citation_count":73,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"30816508","id":"PMC_30816508","title":"MiR‑30e and miR‑92a are related to atherosclerosis by targeting ABCA1.","date":"2019","source":"Molecular medicine reports","url":"https://pubmed.ncbi.nlm.nih.gov/30816508","citation_count":70,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12754274","id":"PMC_12754274","title":"Regulation of ABCA1 expression and cholesterol efflux during adipose differentiation of 3T3-L1 cells.","date":"2003","source":"Journal of lipid research","url":"https://pubmed.ncbi.nlm.nih.gov/12754274","citation_count":64,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"23632854","id":"PMC_23632854","title":"A chloroplast ABC1-like kinase regulates vitamin E metabolism in Arabidopsis.","date":"2013","source":"Plant physiology","url":"https://pubmed.ncbi.nlm.nih.gov/23632854","citation_count":62,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"19170766","id":"PMC_19170766","title":"Retroendocytosis pathway of ABCA1/apoA-I contributes to HDL formation.","date":"2008","source":"Genes to cells : devoted to molecular & cellular mechanisms","url":"https://pubmed.ncbi.nlm.nih.gov/19170766","citation_count":62,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"32819213","id":"PMC_32819213","title":"Diabetes Impairs Cellular Cholesterol Efflux From ABCA1 to Small HDL Particles.","date":"2020","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/32819213","citation_count":62,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15469992","id":"PMC_15469992","title":"Association of ABCA1 with syntaxin 13 and flotillin-1 and enhanced phagocytosis in tangier cells.","date":"2004","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/15469992","citation_count":61,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12909583","id":"PMC_12909583","title":"Identification and characterization of rodent ABCA1 in isolated type II pneumocytes.","date":"2003","source":"American journal of physiology. Lung cellular and molecular physiology","url":"https://pubmed.ncbi.nlm.nih.gov/12909583","citation_count":56,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"21554545","id":"PMC_21554545","title":"Function and regulation of ABCA1--membrane meso-domain organization and reorganization.","date":"2011","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/21554545","citation_count":55,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15891387","id":"PMC_15891387","title":"Assembly of high density lipoprotein by the ABCA1/apolipoprotein pathway.","date":"2005","source":"Current opinion in lipidology","url":"https://pubmed.ncbi.nlm.nih.gov/15891387","citation_count":54,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"32977800","id":"PMC_32977800","title":"Regulation of ATP binding cassette transporter A1 (ABCA1) expression: cholesterol-dependent and - independent signaling pathways with relevance to inflammatory lung disease.","date":"2020","source":"Respiratory research","url":"https://pubmed.ncbi.nlm.nih.gov/32977800","citation_count":53,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16825673","id":"PMC_16825673","title":"Regulation of ABCA1 expression in human keratinocytes and murine epidermis.","date":"2006","source":"Journal of lipid research","url":"https://pubmed.ncbi.nlm.nih.gov/16825673","citation_count":52,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"31662443","id":"PMC_31662443","title":"CXCL12 promotes atherosclerosis by downregulating ABCA1 expression via the CXCR4/GSK3β/β-cateninT120/TCF21 pathway.","date":"2019","source":"Journal of lipid research","url":"https://pubmed.ncbi.nlm.nih.gov/31662443","citation_count":51,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"18356690","id":"PMC_18356690","title":"Effects of fibrate drugs on expression of ABCA1 and HDL biogenesis in hepatocytes.","date":"2008","source":"Journal of cardiovascular pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/18356690","citation_count":49,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"35743794","id":"PMC_35743794","title":"Role of ABCA1 in Cardiovascular Disease.","date":"2022","source":"Journal of personalized medicine","url":"https://pubmed.ncbi.nlm.nih.gov/35743794","citation_count":48,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"32894039","id":"PMC_32894039","title":"The crosstalk of ABCA1 and ANXA1: a potential mechanism for protection against atherosclerosis.","date":"2020","source":"Molecular medicine (Cambridge, Mass.)","url":"https://pubmed.ncbi.nlm.nih.gov/32894039","citation_count":48,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"28129550","id":"PMC_28129550","title":"ATP binding cassette A1 (ABCA1) mediates microparticle formation during high-density lipoprotein (HDL) biogenesis.","date":"2017","source":"Atherosclerosis","url":"https://pubmed.ncbi.nlm.nih.gov/28129550","citation_count":48,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"26109739","id":"PMC_26109739","title":"Increased Systemic and Plaque Inflammation in ABCA1 Mutation Carriers With Attenuation by Statins.","date":"2015","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/26109739","citation_count":47,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"18450749","id":"PMC_18450749","title":"OSBP negatively regulates ABCA1 protein stability.","date":"2008","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/18450749","citation_count":45,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"35575923","id":"PMC_35575923","title":"ABCA1, ABCG1, and Cholesterol Homeostasis.","date":"2022","source":"Advances in experimental medicine and biology","url":"https://pubmed.ncbi.nlm.nih.gov/35575923","citation_count":45,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"32575457","id":"PMC_32575457","title":"ABCA1/ApoE/HDL Signaling Pathway Facilitates Myelination and Oligodendrogenesis after Stroke.","date":"2020","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/32575457","citation_count":44,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"31061090","id":"PMC_31061090","title":"PMP22 Regulates Cholesterol Trafficking and ABCA1-Mediated Cholesterol Efflux.","date":"2019","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/31061090","citation_count":42,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"27343431","id":"PMC_27343431","title":"AMPK activates LXRα and ABCA1 expression in human macrophages.","date":"2016","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/27343431","citation_count":41,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"28768900","id":"PMC_28768900","title":"Plasminogen promotes cholesterol efflux by the ABCA1 pathway.","date":"2017","source":"JCI insight","url":"https://pubmed.ncbi.nlm.nih.gov/28768900","citation_count":41,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"29563219","id":"PMC_29563219","title":"Small molecule inducers of ABCA1 and apoE that act through indirect activation of the LXR pathway.","date":"2018","source":"Journal of lipid research","url":"https://pubmed.ncbi.nlm.nih.gov/29563219","citation_count":41,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"21835264","id":"PMC_21835264","title":"Calpain-mediated ABCA1 degradation: post-translational regulation of ABCA1 for HDL biogenesis.","date":"2011","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/21835264","citation_count":40,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"32155954","id":"PMC_32155954","title":"ABCA1/ABCB1 Ratio Determines Chemo- and Immune-Sensitivity in Human Osteosarcoma.","date":"2020","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/32155954","citation_count":38,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"20185793","id":"PMC_20185793","title":"ABCA1 gene variants regulate postprandial lipid metabolism in healthy men.","date":"2010","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/20185793","citation_count":38,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"28028143","id":"PMC_28028143","title":"ABCA1/ApoE/HDL Pathway Mediates GW3965-Induced Neurorestoration After Stroke.","date":"2016","source":"Stroke","url":"https://pubmed.ncbi.nlm.nih.gov/28028143","citation_count":37,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"19718435","id":"PMC_19718435","title":"LRP1 controls cPLA2 phosphorylation, ABCA1 expression and cellular cholesterol export.","date":"2009","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/19718435","citation_count":37,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"22001232","id":"PMC_22001232","title":"Hepatic ABCA1 and VLDL triglyceride production.","date":"2011","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/22001232","citation_count":36,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"17884990","id":"PMC_17884990","title":"Expression and biological activity of ABCA1 in alveolar epithelial cells.","date":"2007","source":"American journal of respiratory cell and molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/17884990","citation_count":36,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"31795847","id":"PMC_31795847","title":"MiR-200b-3p Functions as an Oncogene by Targeting ABCA1 in Lung Adenocarcinoma.","date":"2019","source":"Technology in cancer research & treatment","url":"https://pubmed.ncbi.nlm.nih.gov/31795847","citation_count":36,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"27862930","id":"PMC_27862930","title":"Piperine inhibits ABCA1 degradation and promotes cholesterol efflux from THP-1-derived macrophages.","date":"2016","source":"Molecular nutrition & food research","url":"https://pubmed.ncbi.nlm.nih.gov/27862930","citation_count":35,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12452478","id":"PMC_12452478","title":"ABCA1: regulation, trafficking and association with heteromeric proteins.","date":"2002","source":"Annals of medicine","url":"https://pubmed.ncbi.nlm.nih.gov/12452478","citation_count":34,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"22429094","id":"PMC_22429094","title":"Hesperetin upregulates ABCA1 expression and promotes cholesterol efflux from THP-1 macrophages.","date":"2012","source":"Journal of natural products","url":"https://pubmed.ncbi.nlm.nih.gov/22429094","citation_count":34,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"26512959","id":"PMC_26512959","title":"IRAK1 mediates TLR4-induced ABCA1 downregulation and lipid accumulation in VSMCs.","date":"2015","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/26512959","citation_count":34,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"17481640","id":"PMC_17481640","title":"ABCA1 expression in humans is associated with physical activity and alcohol consumption.","date":"2007","source":"Atherosclerosis","url":"https://pubmed.ncbi.nlm.nih.gov/17481640","citation_count":33,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"25445880","id":"PMC_25445880","title":"Identification of microRNAs 758 and 33b as potential modulators of ABCA1 expression in human atherosclerotic plaques.","date":"2014","source":"Nutrition, metabolism, and cardiovascular diseases : NMCD","url":"https://pubmed.ncbi.nlm.nih.gov/25445880","citation_count":33,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"32062137","id":"PMC_32062137","title":"Molecular mechanism for nobiletin to enhance ABCA1/G1 expression in mouse macrophages.","date":"2020","source":"Atherosclerosis","url":"https://pubmed.ncbi.nlm.nih.gov/32062137","citation_count":32,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"28591582","id":"PMC_28591582","title":"Hepatocyte ABCA1 Deletion Impairs Liver Insulin Signaling and Lipogenesis.","date":"2017","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/28591582","citation_count":32,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"28655204","id":"PMC_28655204","title":"TRAK2, a novel regulator of ABCA1 expression, cholesterol efflux and HDL biogenesis.","date":"2017","source":"European heart journal","url":"https://pubmed.ncbi.nlm.nih.gov/28655204","citation_count":30,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"8668131","id":"PMC_8668131","title":"Cloning by functional complementation, and inactivation, of the Schizosaccharomyces pombe homologue of the Saccharomyces cerevisiae gene ABC1.","date":"1996","source":"Molecular & general genetics : MGG","url":"https://pubmed.ncbi.nlm.nih.gov/8668131","citation_count":30,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11352567","id":"PMC_11352567","title":"Human and mouse ABCA1 comparative sequencing and transgenesis studies revealing novel regulatory sequences.","date":"2001","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/11352567","citation_count":30,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"31805338","id":"PMC_31805338","title":"Impact of natural products on the cholesterol transporter ABCA1.","date":"2019","source":"Journal of ethnopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/31805338","citation_count":29,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"22955730","id":"PMC_22955730","title":"Myeloid cell-specific ABCA1 deletion protects mice from bacterial infection.","date":"2012","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/22955730","citation_count":29,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"35829808","id":"PMC_35829808","title":"Cholesterol homeostasis regulated by ABCA1 is critical for retinal ganglion cell survival.","date":"2022","source":"Science China. Life sciences","url":"https://pubmed.ncbi.nlm.nih.gov/35829808","citation_count":28,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"33545111","id":"PMC_33545111","title":"Recent advances in the regulation of ABCA1 and ABCG1 by lncRNAs.","date":"2021","source":"Clinica chimica acta; international journal of clinical chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/33545111","citation_count":28,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"37230281","id":"PMC_37230281","title":"QiShenYiQi pill inhibits atherosclerosis by promoting reverse cholesterol transport PPARγ-LXRα/β-ABCA1 pathway.","date":"2023","source":"Journal of ethnopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/37230281","citation_count":28,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15063807","id":"PMC_15063807","title":"A tRNA(TRP) gene mediates the suppression of cbs2-223 previously attributed to ABC1/COQ8.","date":"2004","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/15063807","citation_count":28,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"19828131","id":"PMC_19828131","title":"HIF-1beta determines ABCA1 expression under hypoxia in human macrophages.","date":"2009","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/19828131","citation_count":28,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36055755","id":"PMC_36055755","title":"HDL, cholesterol efflux, and ABCA1: Free from good and evil dualism.","date":"2022","source":"Journal of pharmacological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/36055755","citation_count":27,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"24117441","id":"PMC_24117441","title":"AtSIA1 AND AtOSA1: two Abc1 proteins involved in oxidative stress responses and iron distribution within chloroplasts.","date":"2013","source":"The New phytologist","url":"https://pubmed.ncbi.nlm.nih.gov/24117441","citation_count":27,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15039140","id":"PMC_15039140","title":"Oxysterols trigger ABCA1-mediated basolateral surfactant efflux.","date":"2004","source":"American journal of respiratory cell and molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/15039140","citation_count":27,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36072007","id":"PMC_36072007","title":"Roles of ABCA1 in cancer.","date":"2022","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/36072007","citation_count":26,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"34943934","id":"PMC_34943934","title":"Geniposide Ameliorated Dexamethasone-Induced Cholesterol Accumulation in Osteoblasts by Mediating the GLP-1R/ABCA1 Axis.","date":"2021","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/34943934","citation_count":26,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"39901180","id":"PMC_39901180","title":"Cellular senescence induced by cholesterol accumulation is mediated by lysosomal ABCA1 in APOE4 and AD.","date":"2025","source":"Molecular neurodegeneration","url":"https://pubmed.ncbi.nlm.nih.gov/39901180","citation_count":25,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"32428234","id":"PMC_32428234","title":"ABCA1 Regulates IOP by Modulating Cav1/eNOS/NO Signaling Pathway.","date":"2020","source":"Investigative ophthalmology & visual science","url":"https://pubmed.ncbi.nlm.nih.gov/32428234","citation_count":25,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"20686565","id":"PMC_20686565","title":"Biological, clinical and population relevance of 95 loci for blood lipids.","date":"2010","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/20686565","citation_count":2873,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"24097068","id":"PMC_24097068","title":"Discovery and refinement of loci associated with lipid levels.","date":"2013","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/24097068","citation_count":2409,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"12477932","id":"PMC_12477932","title":"Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences.","date":"2002","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/12477932","citation_count":1479,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"10431236","id":"PMC_10431236","title":"Mutations in ABC1 in Tangier disease and familial high-density lipoprotein deficiency.","date":"1999","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/10431236","citation_count":1430,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"18193043","id":"PMC_18193043","title":"Newly identified loci that influence lipid concentrations and risk of coronary artery disease.","date":"2008","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/18193043","citation_count":1310,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"10431237","id":"PMC_10431237","title":"The gene encoding ATP-binding cassette transporter 1 is mutated in Tangier disease.","date":"1999","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/10431237","citation_count":1292,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"10431238","id":"PMC_10431238","title":"Tangier disease is caused by mutations in the gene encoding ATP-binding cassette transporter 1.","date":"1999","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/10431238","citation_count":1209,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"18193044","id":"PMC_18193044","title":"Six new loci associated with blood low-density lipoprotein cholesterol, high-density lipoprotein cholesterol or triglycerides in humans.","date":"2008","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/18193044","citation_count":1130,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19060906","id":"PMC_19060906","title":"Common variants at 30 loci contribute to polygenic dyslipidemia.","date":"2008","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19060906","citation_count":1113,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"15297675","id":"PMC_15297675","title":"Multiple rare alleles contribute to low plasma levels of HDL cholesterol.","date":"2004","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/15297675","citation_count":829,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19656776","id":"PMC_19656776","title":"DNA methylation differences after exposure to prenatal famine are common and timing- and sex-specific.","date":"2009","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19656776","citation_count":766,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"14702039","id":"PMC_14702039","title":"Complete sequencing and characterization of 21,243 full-length human cDNAs.","date":"2003","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/14702039","citation_count":754,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19060911","id":"PMC_19060911","title":"Loci influencing lipid levels and coronary heart disease risk in 16 European population cohorts.","date":"2008","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19060911","citation_count":695,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"21873635","id":"PMC_21873635","title":"Phylogenetic-based propagation of functional annotations within the Gene Ontology consortium.","date":"2011","source":"Briefings in bioinformatics","url":"https://pubmed.ncbi.nlm.nih.gov/21873635","citation_count":656,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"16192271","id":"PMC_16192271","title":"HDAC6 and microtubules are required for autophagic degradation of aggregated huntingtin.","date":"2005","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16192271","citation_count":599,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"18354102","id":"PMC_18354102","title":"Polymorphisms associated with cholesterol and risk of cardiovascular events.","date":"2008","source":"The New England journal of medicine","url":"https://pubmed.ncbi.nlm.nih.gov/18354102","citation_count":530,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"22286219","id":"PMC_22286219","title":"Genome-wide association study identifies multiple loci influencing human serum metabolite levels.","date":"2012","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/22286219","citation_count":436,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"20385819","id":"PMC_20385819","title":"Genetic variants near TIMP3 and high-density lipoprotein-associated loci influence susceptibility to age-related macular degeneration.","date":"2010","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/20385819","citation_count":433,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"10092505","id":"PMC_10092505","title":"Molecular cloning of the human ATP-binding cassette transporter 1 (hABC1): evidence for sterol-dependent regulation in macrophages.","date":"1999","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/10092505","citation_count":413,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"18523221","id":"PMC_18523221","title":"Association of loss-of-function mutations in the ABCA1 gene with high-density lipoprotein cholesterol levels and risk of ischemic heart disease.","date":"2008","source":"JAMA","url":"https://pubmed.ncbi.nlm.nih.gov/18523221","citation_count":395,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"20385826","id":"PMC_20385826","title":"Genome-wide association study of advanced age-related macular degeneration identifies a role of the hepatic lipase gene (LIPC).","date":"2010","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/20385826","citation_count":376,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"20714348","id":"PMC_20714348","title":"Common inherited variation in mitochondrial genes is not enriched for associations with type 2 diabetes or related glycemic traits.","date":"2010","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/20714348","citation_count":363,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"20864672","id":"PMC_20864672","title":"Genetic variants influencing circulating lipid levels and risk of coronary artery disease.","date":"2010","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/20864672","citation_count":351,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"16207713","id":"PMC_16207713","title":"Lack of ABCA1 considerably decreases brain ApoE level and increases amyloid deposition in APP23 mice.","date":"2005","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16207713","citation_count":312,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"17076584","id":"PMC_17076584","title":"Human immunodeficiency virus impairs reverse cholesterol transport from macrophages.","date":"2006","source":"PLoS biology","url":"https://pubmed.ncbi.nlm.nih.gov/17076584","citation_count":274,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"17604270","id":"PMC_17604270","title":"Mechanism of ATP-binding cassette transporter A1-mediated cellular lipid efflux to apolipoprotein A-I and formation of high density lipoprotein particles.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17604270","citation_count":274,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11162594","id":"PMC_11162594","title":"Apolipoprotein specificity for lipid efflux by the human ABCAI transporter.","date":"2001","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/11162594","citation_count":269,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11086027","id":"PMC_11086027","title":"Age and residual cholesterol efflux affect HDL cholesterol levels and coronary artery disease in ABCA1 heterozygotes.","date":"2000","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/11086027","citation_count":258,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"21347282","id":"PMC_21347282","title":"Genome-wide association study of coronary heart disease and its risk factors in 8,090 African Americans: the NHLBI CARe Project.","date":"2011","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21347282","citation_count":258,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"25589556","id":"PMC_25589556","title":"HDL particle size is a critical determinant of ABCA1-mediated macrophage cellular cholesterol export.","date":"2015","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/25589556","citation_count":254,"is_preprint":false,"source_track":"gene2pubmed"}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":50368,"output_tokens":8058,"usd":0.135987},"stage2":{"model":"claude-opus-4-6","input_tokens":11848,"output_tokens":5110,"usd":0.280485},"total_usd":0.891189,"stage1_batch_id":"msgbatch_01TqNM6p6FsoMBT2jzQTwKBr","stage2_batch_id":"msgbatch_01Ya473eco8sTHbvRymQaU8o","note":"batch pricing = 50% of standard","round2_stage1":{"model":"claude-sonnet-4-6","input_tokens":65333,"output_tokens":9482,"usd":0.169115},"round2_rules_fired":"R3","round2_stage2":{"model":"claude-opus-4-6","input_tokens":13617,"output_tokens":5426,"usd":0.305602}},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1999,\n      \"finding\": \"ABC1/ABCA1 was identified as the gene defective in Tangier disease; blocking ABC1 expression or activity reduces apolipoprotein-mediated lipid efflux from cultured cells, and increasing ABC1 expression enhances it; the protein is incorporated into the plasma membrane in proportion to its level of expression\",\n      \"method\": \"Gene expression microarray, genetic mapping, loss-of-function and gain-of-function cell assays, plasma membrane incorporation assays\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods, foundational discovery replicated across labs\",\n      \"pmids\": [\"10525055\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Mutations in ABC1 cause familial HDL deficiency with defective cellular cholesterol efflux; ABCA1/CERP is essential for HDL formation\",\n      \"method\": \"Mutation detection, fibroblast cholesterol efflux assays, segregation analysis in families\",\n      \"journal\": \"Lancet\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — human genetic + functional cell assays, replicated across multiple families/labs\",\n      \"pmids\": [\"10533863\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Human ABC1 gene contains 49 exons spanning >70 kb; the original Tangier disease kindred carries a homozygous frameshift deletion (nucleotides 3283–3284 in exon 22) predicted to encode a truncated, nonfunctional protein of 1,084 aa\",\n      \"method\": \"Genomic sequencing, restriction-fragment length polymorphism genotyping\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1/2 — direct sequencing of causative mutation in index case, genomic structure defined\",\n      \"pmids\": [\"10535983\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"ABCA1 expression markedly increases cellular cholesterol and phospholipid efflux to lipid-free apoA-I but not to HDL; apoA-I binds directly to ABCA1 as shown by chemical cross-linking and co-immunoprecipitation; ABCA1 is primarily localized on the cell surface; cells overexpressing ABCA1 form plasma membrane protrusions (echinocyte-like) consistent with excess lipid in the outer membrane hemileaflet, suggesting ABCA1 acts as a phospholipid/cholesterol flippase\",\n      \"method\": \"Transfection of full-length mouse ABCA1 cDNA, lipid efflux assays, chemical cross-linking + immunoprecipitation, immunofluorescence confocal microscopy\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — direct binding demonstrated by cross-linking/co-IP plus functional efflux assay and localization\",\n      \"pmids\": [\"10918065\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"ABC1 promotes Ca2+-induced exposure of phosphatidylserine at the outer membrane leaflet, membrane microvesiculation, transbilayer redistribution of spin-labelled phospholipids (measured by prothrombinase assay), and engulfment of apoptotic cells; ABC1-deficient macrophages are impaired in engulfing apoptotic prey, while ABC1 transfectants acquire phagocytic behavior\",\n      \"method\": \"In vivo loss-of-function (ABC1-deficient mice), in vitro gain-of-function (ABC1 transfectants), prothrombinase assay, spin-label phospholipid redistribution assay, phagocytosis assay\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods, both loss- and gain-of-function models\",\n      \"pmids\": [\"10878804\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"LXRα/RXR and LXRβ/RXR heterodimers bind a direct repeat spaced by four nucleotides (DR4 element at −70 to −55 bp) in the ABC1 promoter; mutation of this element abolishes sterol-mediated promoter activation; 22(R)-hydroxycholesterol and 9-cis-retinoic acid cooperatively induce ABCA1 transcription through LXR/RXR\",\n      \"method\": \"Reporter gene transfection, LXR/RXR cotransfection, site-directed mutagenesis of DR4 element\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — promoter mutagenesis combined with receptor cotransfection in macrophages\",\n      \"pmids\": [\"10858438\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"RXR heterodimers with LXR regulate ABCA1 (ABC1) expression and thus reverse cholesterol transport from peripheral tissues; RXR/FXR controls CYP7A1 for bile acid synthesis; rexinoid treatment inhibits cholesterol absorption and induces ABC1\",\n      \"method\": \"Animal pharmacology with receptor-selective agonists, cholesterol balance measurements\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — receptor-selective agonists in multiple models, replicated across multiple receptor contexts\",\n      \"pmids\": [\"10968783\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"cAMP/PKA-dependent signaling increases ABCA1 phosphorylation and promotes apoA-I-mediated cholesterol efflux; PKA inhibitor H-89 reduces efflux by 70% and nearly abolishes ABCA1 phosphorylation; Tangier disease fibroblasts (homozygous ABCA1 defect) fail to respond, while heterozygous familial HDL deficiency cells show partial response\",\n      \"method\": \"cAMP/forskolin treatment, PKA inhibition (H-89), 32P-phosphorylation assays in fibroblasts, cholesterol efflux assays\",\n      \"journal\": \"Journal of lipid research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — direct phosphorylation assay + pharmacological intervention with disease-state controls\",\n      \"pmids\": [\"12454270\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"RARγ/RXR (and RARα/RXR at high levels) directly binds the same DR4 element in the ABCA1 promoter as LXR/RXR (confirmed by chromatin immunoprecipitation) and induces ABCA1 mRNA and protein in macrophages; RARγ-knockout macrophages compensate through RARα upregulation\",\n      \"method\": \"Chromatin immunoprecipitation, cellular cotransfection reporter assays, RARγ−/− mouse macrophages, all-trans-retinoic acid and TTNPB treatments\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — ChIP confirms in-vivo promoter binding, combined with knockout model\",\n      \"pmids\": [\"14560020\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"ABCA1 directly associates with syntaxin 13 and flotillin-1 in Lubrol WX-insoluble lipid raft microdomains in macrophages; co-immunoprecipitation and co-localization confirm interaction; siRNA silencing of syntaxin 13 reduces ABCA1 protein levels and decreases apoA-I-dependent phospholipid efflux; ABCA1 and syntaxin 13 are found as phagosomal proteins, implicating the phagosomal compartment in ABCA1-mediated lipid efflux\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence microscopy, siRNA knockdown, detergent-resistant membrane fractionation, phagocytosis assay\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP, siRNA functional validation, and fractionation with multiple orthogonal methods\",\n      \"pmids\": [\"15469992\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Probucol inhibits ABCA1-mediated cholesterol efflux by impairing translocation of ABCA1 from intracellular compartments to the plasma membrane, reducing cell-surface apoA-I binding, and blocking formation of an ABCA1-linked cholesterol oxidase-sensitive plasma membrane domain; no effect on SR-BI-mediated efflux\",\n      \"method\": \"Fluorescent confocal microscopy, biotinylation assay for plasma membrane ABCA1, 125I-apoA-I binding, cholesterol efflux in Tangier vs. normal fibroblasts\",\n      \"journal\": \"Arteriosclerosis, thrombosis, and vascular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods with disease control (Tangier fibroblasts)\",\n      \"pmids\": [\"15514211\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Unsaturated fatty acids destabilize ABCA1 protein and impair lipid transport via a phospholipase D2 (PLD2) signaling pathway; activated acyl-CoA derivatives stimulate PLD2, which generates diacylglycerols that promote destabilizing serine phosphorylation of ABCA1; PLD2 siRNA abolishes unsaturated fatty acid effects on ABCA1\",\n      \"method\": \"PLD activity assays, PLD inhibitor (1-butanol), PLD2 siRNA knockdown, ABCA1 phosphoserine analysis, acyl-CoA synthetase inhibitor (triacsin C)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — pathway defined by siRNA, pharmacological inhibition, and phosphorylation analysis\",\n      \"pmids\": [\"16118212\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Purified human ABCA1 reconstituted in liposomes shows robust ATPase activity stimulated preferentially by phospholipids with choline head groups (phosphatidylcholine, sphingomyelin); ATPase activity is reduced by cholesterol (~25% decrease at 20% cholesterol) and by glibenclamide; sterols show structure-specific inhibition (β-sitosterol and campesterol inhibit; stigmasterol does not)\",\n      \"method\": \"Purification of human ABCA1 from Sf9 insect cells, liposome reconstitution, in vitro ATPase assay, trypsin limited digestion for conformational analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — purified protein reconstituted in vitro, direct enzymatic characterization\",\n      \"pmids\": [\"16500904\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Beta-cell-specific deletion of Abca1 in mice causes markedly impaired glucose tolerance and defective insulin secretion (with normal insulin sensitivity); isolated islets show altered cholesterol homeostasis; rosiglitazone's beneficial effects on glucose tolerance require beta-cell Abca1, establishing ABCA1 as necessary for beta-cell cholesterol homeostasis and insulin secretion\",\n      \"method\": \"Conditional beta-cell-specific Abca1 knockout mice, glucose tolerance tests, insulin secretion assays in vitro, pharmacological (rosiglitazone) rescue\",\n      \"journal\": \"Nature medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — conditional KO with specific phenotypic readout, pharmacological rescue\",\n      \"pmids\": [\"17322896\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"ABCA1 and apoA-I undergo endocytosis via a clathrin- and Rab5-mediated pathway and recycle back to the cell surface via a Rab4-mediated route; ~30% of endocytosed ABCA1 is recycled; blocking receptor-mediated endocytosis increases ABCA1 at the cell surface and blocks apoA-I internalization; the retroendocytosis pathway contributes to HDL formation especially when excess lipoprotein-derived cholesterol has accumulated in cells\",\n      \"method\": \"HA-tagged and GFP-tagged ABCA1 constructs, clathrin/Rab5/Rab4 inhibition, cholesterol efflux assays with/without endocytosis block\",\n      \"journal\": \"Genes to cells\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — live-cell trafficking analysis with tagged constructs and multiple pathway inhibitors\",\n      \"pmids\": [\"19170766\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"OSBP negatively regulates ABCA1 protein stability in a sterol-binding domain-dependent manner; OSBP knockdown by RNAi increases ABCA1 protein half-life 3-fold without affecting ABCA1 mRNA or LXR activity; a mutation in the OSBP sterol-binding domain prevents ABCA1 destabilization\",\n      \"method\": \"RNAi knockdown of OSBP, ABCA1 protein half-life measurement, OSBP mutagenesis, cholesterol efflux assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — RNAi plus domain-specific mutagenesis with quantitative protein stability measurements\",\n      \"pmids\": [\"18450749\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"ABCA1 deficiency (knockout) causes increased macrophage inflammatory signaling via TLR4; sterol efflux activities of ABCA1 and ABCG1 modulate macrophage TLR4 signaling, inflammatory cytokine expression, and lymphocyte proliferative responses by modulating sterol levels and lipid organization in cell membranes\",\n      \"method\": \"ABCA1/ABCG1 macrophage knockout mouse models, TLR4 signaling assays, cytokine measurement, lymphocyte proliferation assays\",\n      \"journal\": \"Arteriosclerosis, thrombosis, and vascular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic knockout models with defined inflammatory signaling readouts\",\n      \"pmids\": [\"19797709\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"LRP1 deficiency increases PDGFRβ/MAPK signaling, leading to cPLA2 phosphorylation and arachidonic acid release, which suppresses LXR/RXR activation at the ABCA1 promoter, greatly reducing ABCA1 expression and cholesterol efflux; this identifies LRP1 as a regulator of LXR-mediated ABCA1 transcription\",\n      \"method\": \"LRP1-deficient cells, PDGFRβ/MAPK pathway analysis, cPLA2 phosphorylation assay, LXR promoter activity, ABCA1 expression and cholesterol efflux measurements\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — pathway placed by sequential genetic/pharmacological dissection in single study\",\n      \"pmids\": [\"19718435\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"ABCA1 is degraded by calpain in early endosomes after endocytosis; when HDL biogenesis is ongoing (helical apolipoproteins interacting with ABCA1), ABCA1 becomes resistant to calpain and is recycled to the cell surface; proteins such as α1-syntrophin, LXRβ, and calmodulin retard calpain-mediated ABCA1 degradation; pharmacological inhibition of calpain increases ABCA1 activity and HDL biogenesis in vitro and in vivo\",\n      \"method\": \"Calpain inhibitor experiments, endosomal fractionation, interaction protein studies, in vivo pharmacology\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — defined degradation pathway with in vitro and in vivo pharmacological validation, multiple interacting proteins characterized\",\n      \"pmids\": [\"21835264\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"ApoA-I interaction with ABCA1 activates multiple intracellular signaling pathways including JAK2/STAT3, protein kinase A, Rho GTPase CDC42, and PKC; PKA and CDC42 activation regulates lipid efflux; PKC activation stabilizes ABCA1 protein; JAK2/STAT3 activation regulates both lipid efflux and anti-inflammatory activity\",\n      \"method\": \"Signaling pathway inhibitors, co-immunoprecipitation, siRNA knockdown studies in macrophages\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — multiple signaling pathways identified but mostly single-method evidence per pathway\",\n      \"pmids\": [\"21920460\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"miR-33a overexpression in human and mouse islets reduces ABCA1 expression, decreases glucose-stimulated insulin secretion, and increases cholesterol; cholesterol depletion (methyl-β-cyclodextrin or mevastatin) rescues miR-33a-induced reduction in insulin secretion; ABCA1 overexpression in beta-cell-specific ABCA1 knockout islets rescues normal insulin secretion\",\n      \"method\": \"Adenoviral miR-33a overexpression, miR-33a inhibition, ABCA1 overexpression in KO islets, cholesterol depletion rescue experiments\",\n      \"journal\": \"Diabetes\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple genetic and pharmacological rescue approaches with specific functional readout\",\n      \"pmids\": [\"22315319\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"ABCA1 deficiency in mouse brain causes cortical astrogliosis, increased MAPK activation, and augmented LPS-induced TNFα secretion and decreased phagocytic activity in microglia; astrocyte-specific ABCA1 deletion reduces cortical ApoE levels, establishing that astrocyte ABCA1 specifically regulates brain ApoE levels; whole-brain ABCA1 deficiency leads to cortical neuronal death in aging mice\",\n      \"method\": \"Cell-type-specific ABCA1 conditional knockout mice (brain, neuronal, astrocytic), LPS challenge, MAPK analysis, TNFα ELISA, phagocytosis assay, ApoE protein measurement\",\n      \"journal\": \"Neurobiology of disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — cell-type-specific conditional knockouts with multiple mechanistic readouts\",\n      \"pmids\": [\"23376685\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Apoptotic cells trigger upregulation of ABCA1 mRNA and protein through a plasma membrane-initiated pathway involving the phagocytic receptor BAI1 (recognizing phosphatidylserine on apoptotic cells), and intracellular intermediates ELMO1 and Rac1; this pathway functions independently of the LXR sterol-sensing machinery; BAI1-deficient mice on high-fat diet accumulate apoptotic cells in aortic roots with altered lipid profiles\",\n      \"method\": \"Primary macrophages from BAI1-, ELMO1-, Rac1-knockout mice, ABCA1 mRNA/protein induction assays, BAI1 transgenic mice, high-fat diet model\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple genetic knockouts defining pathway, confirmed in vivo\",\n      \"pmids\": [\"26075824\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"ABCA1 mediates production of microparticles (50–250 nm) containing cholesterol and flotillin-2; apoA-I markedly increases microparticle release; inhibition of ABCA1 with probucol or depletion of membrane cholesterol with methyl-β-cyclodextrin reduces microparticle release and nascent HDL formation; microparticles contribute ~30% of ABCA1/apoA-I-mediated cholesterol efflux\",\n      \"method\": \"Inducible ABCA1 expression system (mifepristone-controlled BHK cells), pharmacological ABCA1 inhibition, particle characterization by size and marker analysis, efflux quantitation\",\n      \"journal\": \"Atherosclerosis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — inducible expression + pharmacological inhibition in multiple cell lines, single lab\",\n      \"pmids\": [\"28129550\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"TRAK2 is a novel negative regulator of LXR-mediated ABCA1 transcription; TRAK2 siRNA knockdown increases LXR binding at the ABCA1 promoter, increases ABCA1 mRNA and protein, and promotes cholesterol efflux to apoA-I; the effect on efflux is abolished in the absence of ABCA1\",\n      \"method\": \"TRAK2 siRNA knockdown, luciferase reporter, chromatin immunoprecipitation (LXR binding at ABCA1 promoter), cholesterol efflux assay with/without ABCA1\",\n      \"journal\": \"European heart journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP and reporter assay confirm promoter binding, siRNA knockdown with ABCA1-null control\",\n      \"pmids\": [\"28655204\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Hepatocyte-specific ABCA1 knockout reduces plasma membrane free cholesterol and impairs lysosomal free cholesterol trafficking to the plasma membrane, leading to defective insulin-stimulated Akt phosphorylation, reduced SREBP-1c activation, and suppressed lipogenic gene expression—but with intact gluconeogenesis, demonstrating selective insulin resistance\",\n      \"method\": \"Hepatocyte-specific ABCA1 KO mice, plasma membrane cholesterol fractionation, insulin signaling (Akt phosphorylation), SREBP-1c activation, lipogenic gene expression, glucose/insulin tolerance tests\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — conditional KO with multiple mechanistic readouts across cholesterol trafficking and signaling\",\n      \"pmids\": [\"28591582\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"ABCA1 is a membrane phospholipid translocase: its enzymatic activity transfers phospholipid molecules from the cytoplasmic leaflet to the exofacial leaflet of the plasma membrane, creating lipid domains that bind apoA-I; ~10% of cell-surface apoA-I directly interacts with and stabilizes ABCA1; most surface-associated apoA-I is bound to lipid domains created by ABCA1 activity; amphipathic α-helices in apoA-I solubilize these domains to form nascent HDL\",\n      \"method\": \"Review synthesizing structure-function studies including mutagenesis, cross-linking, and lipid translocation assays from multiple labs\",\n      \"journal\": \"Journal of lipid research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — synthesis of reconstitution, mutagenesis, and direct translocation assay data across multiple labs\",\n      \"pmids\": [\"29305383\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"ApoE4 promotes greater expression of ARF6 compared with ApoE3, trapping ABCA1 in late endosomes and impairing its recycling to the cell membrane; this is associated with lower ABCA1-mediated cholesterol efflux, greater percentage of lipid-free ApoE particles, and lower Aβ degradation capacity; enhancing ABCA1 activity rescued impaired Aβ degradation in ApoE4-treated cells and reduced ApoE and ABCA1 aggregation in hippocampus\",\n      \"method\": \"ARF6 expression analysis, ABCA1 membrane trafficking assays (endosomal fractionation), cholesterol efflux assays, ApoE lipidation analysis, ApoE4-targeted replacement mice, human CSF analysis\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods including cell, animal model, and human CSF data\",\n      \"pmids\": [\"31641056\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PMP22 interacts with ABCA1 at the Schwann cell plasma membrane (co-immunoprecipitation from Schwann cell and nerve lysates); absence of PMP22 reduces ABCA1 localization to the cell membrane and diminishes apoE secretion and ABCA1-mediated cholesterol efflux; ABCA1 knockout increases PMP22 expression with aberrant subcellular processing\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence co-localization, PMP22 KO mice, ABCA1 KO mice, cholesterol efflux assay, membrane capacitance/resistance electrophysiology\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP and bidirectional KO experiments with functional efflux and electrophysiological readouts\",\n      \"pmids\": [\"31061090\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ABCA1 regulates intraocular pressure (IOP) through the caveolin-1/eNOS/NO signaling pathway; ABCA1 upregulation in aqueous plexus cells decreases caveolin-1 expression, increases eNOS expression and NO production, decreases transendothelial electrical resistance; ABCA1 downregulation has the opposite effects; intracameral ABCA1 agonist GW3965 reduces IOP and increases conventional aqueous humor outflow facility in vivo\",\n      \"method\": \"ABCA1 shRNA lentiviral knockdown, ABCA1 agonist (GW3965) treatment in Schlemm's canal cells, transendothelial electrical resistance, NO measurement, eNOS/caveolin-1 protein quantification, in vivo IOP and outflow facility measurement\",\n      \"journal\": \"Investigative ophthalmology & visual science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — gain- and loss-of-function in cells plus in vivo functional validation, single lab\",\n      \"pmids\": [\"32428234\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Caveolin-1, a sensor of cellular cholesterol accumulation, promotes ABCA1 lysosomal trafficking (endolysosomal trapping) identified by unbiased proteomics; oxysterol accumulation in APOE4 and AD induces caveolin-1 and ABCA1 lysosomal trapping, leading to mTORC1 activation and cellular senescence; cyclodextrin treatment reduces brain oxysterol levels, ABCA1 lysosome trapping, mTORC1 activation, and attenuates senescence markers in APOE4-TR mice\",\n      \"method\": \"Unbiased discovery proteomics, ABCA1 knockout cell lines and mouse models, APOE4-targeted replacement mice, iPSC-derived astrocytes, mTORC1 activity assays, cyclodextrin pharmacological rescue, ROSMAP human brain transcriptomics/immunofluorescence\",\n      \"journal\": \"Molecular neurodegeneration\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — unbiased proteomics discovery validated in multiple models (cells, mice, human brain) with pharmacological rescue\",\n      \"pmids\": [\"39901180\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ABCA1 is an ATP-hydrolyzing plasma membrane phospholipid translocase that flips phospholipids from the cytoplasmic to the exofacial leaflet, creating cholesterol- and phospholipid-enriched membrane domains that bind lipid-free apoA-I (directly via ~10% of surface-bound apoA-I and indirectly via lipid domains); apoA-I's amphipathic helices solubilize these domains to generate nascent HDL particles, a process that is transcriptionally driven by LXR/RXR and RAR/RXR via a DR4 promoter element, post-translationally regulated by cAMP/PKA-mediated phosphorylation (activating), PLD2/diacylglycerol-mediated serine phosphorylation (destabilizing), and calpain-mediated endosomal degradation (restrained by apoA-I binding and by α1-syntrophin/calmodulin/LXRβ interactions); additionally, ABCA1 acts as a signaling receptor whose interaction with apoA-I activates JAK2/STAT3, PKA, CDC42, and PKC pathways, modulates membrane lipid raft composition to suppress TLR4-driven inflammation, controls beta-cell cholesterol homeostasis required for insulin secretion, regulates hepatocyte plasma membrane free cholesterol for proper insulin/lipogenic signaling, promotes phosphatidylserine exposure and apoptotic cell engulfment, and in astrocytes is specifically required for brain ApoE lipidation.\"\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1999,\n      \"finding\": \"ABC1/ABCA1 was identified as the gene defective in Tangier disease through combined gene expression microarray analysis, genetic mapping, and biochemical studies. Blocking ABC1 expression or activity reduces apolipoprotein-mediated lipid efflux from cultured cells, while increasing ABC1 expression enhances it. ABC1 protein is incorporated into the plasma membrane in proportion to its expression level.\",\n      \"method\": \"Gene expression microarray, genetic mapping, loss-of-function (siRNA/antibody), gain-of-function overexpression, plasma membrane fractionation\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods, replicated across independent labs in concurrent papers\",\n      \"pmids\": [\"10525055\", \"10431236\", \"10431237\", \"10431238\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Mutations in ABC1 were identified as the major cause of both Tangier disease and familial HDL deficiency associated with defective cholesterol efflux, establishing ABC1/ABCA1 as essential for HDL formation and the cholesterol efflux regulatory pathway.\",\n      \"method\": \"Genomic sequencing, restriction-fragment length polymorphism, cellular cholesterol efflux assay\",\n      \"journal\": \"Lancet\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct mutation identification with functional validation in patient fibroblasts, replicated by multiple independent groups\",\n      \"pmids\": [\"10533863\", \"10535983\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"ABCA1 expression drives specific binding of lipid-free apoA-I at the cell surface. Chemical cross-linking and immunoprecipitation showed apoA-I binds directly to ABCA1 protein. ABCA1 preferentially binds lipid-free apoA-I but not HDL. Cells overexpressing ABCA1 display plasma membrane protrusions (echinocyte-like morphology) consistent with excess lipids in the outer membrane leaflet, suggesting ABCA1 acts as a phospholipid/cholesterol flippase.\",\n      \"method\": \"Chemical cross-linking, co-immunoprecipitation, radiolabeled lipid efflux assay, immunofluorescence confocal microscopy, apoA-I binding assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — direct binding demonstrated by cross-linking/co-IP plus functional efflux assay in transfected cells\",\n      \"pmids\": [\"10918065\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"ABC1 promotes Ca2+-induced exposure of phosphatidylserine at the plasma membrane outer leaflet and facilitates membrane microvesiculation and transbilayer redistribution of phospholipids. ABC1-deficient macrophages have impaired ability to engulf apoptotic cells, while ABC1 transfectants acquire phagocytic behavior, linking ABCA1-driven phosphatidylserine redistribution to apoptotic cell clearance.\",\n      \"method\": \"In vivo loss-of-function (ABC1-deficient mice), in vitro gain-of-function (transfection), prothrombinase assay, membrane microvesiculation assay, spin-labeled phospholipid transbilayer redistribution, phagocytosis assay\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — orthogonal in vivo and in vitro models with multiple biochemical readouts\",\n      \"pmids\": [\"10878804\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"LXRα/RXR and LXRβ/RXR heterodimers bind to a direct repeat spaced by four nucleotides (DR4) element at positions -70 to -55 bp in the ABCA1 promoter and drive sterol-dependent transactivation. Mutations in this DR4 element abolish sterol-mediated activation, establishing LXR/RXR as direct transcriptional regulators of ABCA1.\",\n      \"method\": \"Promoter-reporter transfection assay, site-directed mutagenesis of promoter, co-transfection with LXR/RXR expression vectors\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — promoter mutagenesis plus receptor co-transfection with multiple sterol conditions\",\n      \"pmids\": [\"10858438\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"RXR heterodimers with oxysterol receptors (LXRs) regulate reverse cholesterol transport by controlling expression of the ABC1 transporter in peripheral tissues, while RXR/FXR heterodimers regulate bile acid synthesis. Treatment of animals with rexinoids markedly inhibited cholesterol absorption and repressed bile acid synthesis through these pathways.\",\n      \"method\": \"Receptor-selective agonist pharmacology in mice, tissue cholesterol balance measurements, gene expression analysis\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — in vivo pharmacology with receptor-selective agonists and multiple metabolic endpoints, highly cited\",\n      \"pmids\": [\"10968783\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"cAMP/PKA-dependent pathway phosphorylates ABCA1, with maximum phosphorylation reached within 10 minutes representing a 260% increase over basal levels. PKA inhibitor H-89 reduced cholesterol efflux by 70% and almost completely inhibited ABCA1 phosphorylation. Tangier disease (homozygous ABCA1-deficient) cells showed no increase in ABCA1 phosphorylation or efflux upon cAMP stimulation, whereas familial HDL deficiency heterozygotes retained partial response.\",\n      \"method\": \"Radiolabeled phosphorylation assay, cholesterol efflux assay, PKA inhibitor (H-89), patient fibroblasts (Tangier disease and familial HDL deficiency)\",\n      \"journal\": \"Journal of lipid research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct phosphorylation assay with pharmacological inhibition and genetic controls (Tangier fibroblasts)\",\n      \"pmids\": [\"12454270\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"RARγ/RXR directly activates the ABCA1 promoter through the same DR4 element used by LXR/RXR. Chromatin immunoprecipitation in macrophages confirmed binding of RARγ/RXR to the ABCA1 promoter DR4 element in the presence of all-trans retinoic acid. In RARγ-knockout macrophages, marked upregulation of RARα compensated and still induced ABCA1.\",\n      \"method\": \"Promoter-reporter transfection, chromatin immunoprecipitation (ChIP), RARγ knockout mouse macrophages, dose-response with retinoic acid receptor agonists\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — ChIP plus genetic KO rescue and reporter assay, multiple orthogonal methods\",\n      \"pmids\": [\"14560020\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Probucol inhibits ABCA1-mediated cholesterol efflux by impairing translocation of ABCA1 from intracellular compartments to the plasma membrane. Probucol also inhibits formation of an ABCA1-linked cholesterol oxidase-sensitive plasma membrane domain and reduces cell-surface apoA-I binding. This effect was absent in Tangier patient fibroblasts lacking functional ABCA1, confirming specificity.\",\n      \"method\": \"Fluorescent confocal microscopy, biotinylation surface assay, cholesterol oxidase-sensitive domain assay, radiolabeled apoA-I binding assay, Tangier fibroblast controls\",\n      \"journal\": \"Arteriosclerosis, thrombosis, and vascular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods with Tangier disease genetic control\",\n      \"pmids\": [\"15514211\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"ABCA1 directly associates with syntaxin 13 (but not syntaxins 3 or 6) and flotillin-1, as demonstrated by immunoprecipitation. This complex resides in Lubrol WX-insoluble lipid raft microdomains and in phagosomes. siRNA silencing of syntaxin 13 reduced ABCA1 protein levels and significantly decreased apoA-I-dependent phospholipid efflux. Tangier fibroblasts with mutated ABCA1 showed enhanced phagocytosis that was normalized by re-expression of functional ABCA1.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, immunofluorescence microscopy, detergent-resistant membrane fractionation, phagocytosis assay, lipid efflux assay\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP plus siRNA functional validation and genetic controls\",\n      \"pmids\": [\"15469992\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Unsaturated fatty acids destabilize ABCA1 through a phospholipase D2 (PLD2) signaling pathway. Long-chain acyl-CoA synthetase inhibitor triacsin C reversed this effect. PLD2 siRNA abolished unsaturated fatty acid-induced reduction in ABCA1 levels, increased serine phosphorylation of ABCA1, and inhibition of lipid transport activity. Diacylglycerol analogs also increased ABCA1 serine phosphorylation, implicating PLD2-generated diacylglycerols in destabilizing ABCA1 phosphorylation.\",\n      \"method\": \"siRNA knockdown of PLD2, pharmacological inhibitors (triacsin C, 1-butanol), phosphorylation assay, ABCA1 protein stability assay, lipid efflux assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — siRNA plus pharmacological validation with mechanistic phosphorylation readout\",\n      \"pmids\": [\"16118212\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Purified human ABCA1 reconstituted into liposomes exhibits robust ATPase activity. ATPase activity is stimulated preferentially by phospholipids with choline head groups (phosphatidylcholine and sphingomyelin) and inhibited by addition of cholesterol (25% decrease at 20% cholesterol). Beta-sitosterol and campesterol showed similar inhibitory effects but stigmasterol did not, indicating structure-specific sterol interactions. Glibenclamide suppressed ABCA1 ATPase activity, providing a biochemical basis for its inhibition of cholesterol efflux.\",\n      \"method\": \"Protein purification from Sf9 insect cells, liposome reconstitution, ATPase activity assay, trypsin limited-digestion conformational analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstitution with purified protein, direct enzymatic assay\",\n      \"pmids\": [\"16500904\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"ABCA1 mediates the mechanism of nascent HDL formation: binding of a small pool of apoA-I to ABCA1 enhances net phospholipid translocation to the plasma membrane exofacial leaflet, creating membrane strain relieved by formation of exovesiculated lipid domains. ApoA-I then binds at high affinity to these curved membrane domains and spontaneously solubilizes them to create discoidal nascent HDL particles containing 2–4 apoA-I molecules.\",\n      \"method\": \"Cell-based lipid efflux assay, apoA-I binding kinetics, analysis of HDL particle composition and size, phospholipid translocation assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — systematic mechanistic dissection with multiple complementary biochemical assays\",\n      \"pmids\": [\"17604270\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Beta-cell-specific inactivation of Abca1 in mice causes markedly impaired glucose tolerance and defective insulin secretion with normal insulin sensitivity. Isolated islets from these mice show altered cholesterol homeostasis and impaired insulin secretion in vitro. Rosiglitazone (a PPARγ activator that upregulates Abca1 in beta-cells) requires beta-cell Abca1 for its beneficial effects on glucose tolerance, establishing a role for ABCA1 in beta-cell cholesterol homeostasis and insulin secretion.\",\n      \"method\": \"Conditional beta-cell-specific knockout mice, glucose tolerance tests, insulin secretion assay, ex vivo islet cholesterol measurement\",\n      \"journal\": \"Nature medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — cell-type-specific KO with defined phenotype, pharmacological rescue experiment\",\n      \"pmids\": [\"17322896\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"ABCA1 and apoA-I undergo endocytosis via a clathrin- and Rab5-mediated pathway and are recycled back to the cell surface via a Rab4-mediated route. Approximately 30% of endocytosed ABCA1 is recycled to the cell surface. When receptor-mediated endocytosis is inhibited, apoA-I internalization is blocked and cholesterol efflux from cells with excess lipoprotein-derived cholesterol decreases, while efflux from cells without excess cholesterol increases, indicating that retroendocytosis contributes to HDL formation particularly when excess cholesterol has accumulated.\",\n      \"method\": \"Extracellular HA-tagged and intracellular GFP-tagged ABCA1 constructs, clathrin inhibition, dominant-negative Rab protein expression, cholesterol efflux assay\",\n      \"journal\": \"Genes to cells\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — engineered tagged constructs with pathway-specific inhibitors and functional efflux readout\",\n      \"pmids\": [\"19170766\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"OSBP (oxysterol-binding protein) negatively regulates ABCA1 protein stability. OSBP knockdown increased ABCA1 protein half-life by 3-fold without affecting ABCA1 mRNA or LXR transcriptional activity. A mutation in the OSBP sterol-binding domain (but not mutations abrogating Golgi or ER interactions) prevented OSBP-mediated reduction of ABCA1, indicating that OSBP destabilizes ABCA1 via its sterol-binding domain.\",\n      \"method\": \"siRNA knockdown, ABCA1 protein half-life (cycloheximide chase), LXR reporter assay, OSBP domain mutants, cholesterol efflux assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — siRNA plus domain-specific mutagenesis with protein stability readout\",\n      \"pmids\": [\"18450749\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"LRP1 deficiency leads to increased PDGFRβ signaling and sequential MAPK activation, which increases phosphorylation of cytosolic phospholipase A2 (cPLA2). Activated cPLA2 releases arachidonic acid, which suppresses LXR/RXR heterodimer activation at the ABCA1 promoter, resulting in greatly reduced ABCA1 expression. Thus LRP1 regulates ABCA1 expression and reverse cholesterol transport by controlling cPLA2 activation.\",\n      \"method\": \"LRP1 knockout cell lines, signaling pathway inhibitors, cPLA2 phosphorylation assay, ABCA1 promoter reporter, cholesterol efflux assay\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with signaling pathway analysis, but single study\",\n      \"pmids\": [\"19718435\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"ABCA1 and ABCG1 modulate macrophage inflammatory cytokine and chemokine expression by controlling sterol efflux and cellular membrane sterol levels. Transporter deficiency causes increased signaling via Toll-like receptors including TLR4, mechanistically linking cholesterol efflux activity to anti-inflammatory and immunosuppressive functions.\",\n      \"method\": \"ABCA1/ABCG1 knockout macrophages, cytokine/chemokine expression assays, TLR signaling pathway analysis\",\n      \"journal\": \"Arteriosclerosis, thrombosis, and vascular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — genetic KO phenotype but pathway placement partly inferential\",\n      \"pmids\": [\"19797709\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"ABCA1 protein is degraded by calpain in early endosomes after endocytosis. When HDL biogenesis is ongoing (helical apolipoproteins interacting with ABCA1), ABCA1 becomes resistant to calpain and is recycled to the cell surface. Factors that interact with ABCA1 (α1-syntrophin, LXRβ, calmodulin) retard this calpain-mediated degradation. Pharmacological inhibition of calpain increases ABCA1 activity and HDL biogenesis in vitro and in vivo.\",\n      \"method\": \"Calpain inhibitors, subcellular fractionation, ABCA1 protein stability assay, endocytosis tracking, in vivo pharmacology\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal approaches including in vivo validation, replicated across studies\",\n      \"pmids\": [\"21835264\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"ApoA-I/ABCA1 interaction activates multiple downstream signaling pathways including JAK2/STAT3, protein kinase A, Rho GTPase CDC42, and protein kinase C. PKA and CDC42 activation regulates ABCA1-mediated lipid efflux, PKC activation stabilizes ABCA1 protein, and JAK2/STAT3 activation regulates both lipid efflux and anti-inflammatory effects, demonstrating that ABCA1 functions both as a lipid transporter and a signaling receptor.\",\n      \"method\": \"Kinase inhibitors, dominant-negative constructs, phosphorylation assays, cholesterol efflux assay, cytokine production assay\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — review integrating multiple published findings, individual pathway studies with moderate rigor\",\n      \"pmids\": [\"21920460\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"miR-33a overexpression in human and mouse islets reduces ABCA1 expression, decreases glucose-stimulated insulin secretion, and increases cholesterol levels. The miR-33a-induced reduction in insulin secretion was rescued by cholesterol depletion (methyl-β-cyclodextrin or mevastatin), confirming that miR-33a suppresses insulin secretion through ABCA1-dependent islet cholesterol accumulation.\",\n      \"method\": \"Adenoviral miR-33a overexpression, miR-33a inhibition in ApoE-KO islets, ABCA1 overexpression rescue, cholesterol measurement, glucose-stimulated insulin secretion assay\",\n      \"journal\": \"Diabetes\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — gain and loss of function with multiple rescue experiments confirming ABCA1-cholesterol-insulin axis\",\n      \"pmids\": [\"22315319\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Apoptotic cells trigger a BAI1→ELMO1→Rac1 signaling pathway that rapidly upregulates ABCA1 mRNA and protein, independently of the LXR sterol-sensing pathway. Primary macrophages from BAI1-, ELMO1-, or Rac1-deficient mice showed attenuated ABCA1 induction. BAI1 overexpression increased ABCA1 induction in response to apoptotic cells, and BAI1-deficient mice on high-fat diet had increased apoptotic cells in aortic roots with altered lipid profiles.\",\n      \"method\": \"Primary macrophages from BAI1/ELMO1/Rac1 KO mice, ABCA1 mRNA/protein induction assay, transgenic BAI1 overexpression, high-fat diet in vivo model\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple genetic KO models plus in vivo validation with defined pathway\",\n      \"pmids\": [\"26075824\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"AMPK activation (pharmacological or genetic) increases ABCA1 and LXRα mRNA and protein in human macrophages, resulting in increased cholesterol efflux. Silencing LXRα (but not LXRβ) attenuated ABCA1 expression after AMPK activation. ChIP showed LXRα binding to the LXR responsive element in the ABCA1 promoter upon AMPK activation, placing AMPK upstream of LXRα in the regulatory pathway.\",\n      \"method\": \"AMPK siRNA/overexpression, pharmacological AMPK activators, LXRα siRNA, luciferase reporter assay, ChIP, cholesterol efflux assay\",\n      \"journal\": \"The international journal of biochemistry & cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic and pharmacological interventions with ChIP confirmation of promoter binding\",\n      \"pmids\": [\"27343431\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"TRAK2 knockdown significantly increases cholesterol efflux and ABCA1 mRNA and protein expression. TRAK2 effect on cholesterol efflux was abolished in the absence of ABCA1, confirming ABCA1 dependency. ChIP showed that TRAK2 knockdown increases LXR binding at the ABCA1 promoter, establishing TRAK2 as a novel negative regulator of LXR-mediated ABCA1 transcription.\",\n      \"method\": \"siRNA knockdown (TRAK2 and ABCA1), ChIP, cholesterol efflux assay, mRNA/protein expression, human genetic-transcriptomic data correlation\",\n      \"journal\": \"European heart journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — siRNA knockdown with ChIP and ABCA1-dependency rescue experiment\",\n      \"pmids\": [\"28655204\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Hepatocyte-specific ABCA1 knockout reduces plasma membrane free cholesterol content and impairs trafficking of lysosomal free cholesterol to the plasma membrane. This leads to reduced insulin-stimulated Akt phosphorylation, reduced SREBP-1c activation, and suppressed lipogenic gene expression, demonstrating that ABCA1 maintains hepatocyte plasma membrane cholesterol for efficient insulin signaling and lipogenesis.\",\n      \"method\": \"Hepatocyte-specific ABCA1 knockout mice, plasma membrane cholesterol fractionation, insulin signaling assays (Akt phosphorylation), SREBP-1c activation, glucose/insulin tolerance tests\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — cell-type-specific KO with mechanistic dissection of PM cholesterol and signaling\",\n      \"pmids\": [\"28591582\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"ApoE4 promotes greater expression of ARF6 compared with ApoE3, trapping ABCA1 in late endosomes and impairing its recycling to the cell membrane. This results in lower ABCA1-mediated cholesterol efflux, a greater percentage of lipid-free ApoE particles, and lower Aβ degradation capacity. Enhancing ABCA1 activity rescued impaired Aβ degradation in ApoE4-treated cells and reduced ApoE and ABCA1 aggregation in the hippocampus of ApoE4 knock-in mice.\",\n      \"method\": \"ARF6 expression analysis, ABCA1 trafficking assay (late endosome trapping), cholesterol efflux assay, ApoE lipidation assay, Aβ degradation assay, in vivo ApoE4-targeted replacement mice\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — mechanistic cell biology with in vivo validation in knock-in model\",\n      \"pmids\": [\"31641056\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PMP22 (peripheral myelin protein 22) physically interacts with ABCA1 at the Schwann cell plasma membrane (demonstrated by co-immunoprecipitation). Absence of PMP22 results in reduced ABCA1 localization to the cell membrane and diminished apoE secretion and ABCA1-mediated cholesterol efflux, despite upregulation of ABCA1 and apoE mRNA/protein. Conversely, ABCA1 knockout elevates PMP22 expression and aberrant processing.\",\n      \"method\": \"Co-immunoprecipitation from Schwann cell and nerve lysates, immunofluorescence co-localization, ABCA1 KO mice, PMP22 KO mice, cholesterol efflux assay, whole-cell patch clamp\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP with genetic KO models and functional efflux validation\",\n      \"pmids\": [\"31061090\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"ABCA1 deficiency in the brain of ABCA1 knockout mice causes a considerable decrease in soluble brain apoE protein levels and increases amyloid deposition in APP23 transgenic mice, including increased parenchymal and vascular (cerebral amyloid angiopathy) amyloid. The results establish ABCA1 as a regulator of apoE lipidation/solubility in brain and a modifier of amyloid pathology.\",\n      \"method\": \"ABCA1 knockout crossed with APP23 transgenic mice, Aβ immunoreactivity, thioflavine S staining, cerebral amyloid angiopathy assessment, apoE protein quantification (soluble vs insoluble fractions)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO in disease model with multiple amyloid and apoE readouts\",\n      \"pmids\": [\"16207713\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"HIV-1 Nef protein binds ABCA1 and impairs ABCA1-dependent cholesterol efflux from macrophages through two mechanisms: post-transcriptional downregulation of ABCA1 and redistribution of ABCA1 to the plasma membrane with inhibited apoA-I internalization. This causes lipid accumulation in HIV-infected macrophages resembling foam cells. Stimulation of cholesterol efflux reduced HIV virion infectivity by decreasing virion-associated cholesterol.\",\n      \"method\": \"Nef transfection in murine macrophages, ABCA1 protein expression analysis, ABCA1 trafficking (redistribution assay), co-immunoprecipitation (Nef-ABCA1 binding), cholesterol efflux assay, virion cholesterol measurement\",\n      \"journal\": \"PLoS biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct Nef-ABCA1 binding plus multiple functional assays with mechanistic dissection\",\n      \"pmids\": [\"17076584\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"HIF-1β availability determines ABCA1 expression and cholesterol efflux in macrophages under hypoxia. HIF-1 complex specifically binds to the HIF-1 response element in the ABCA1 promoter and increases ABCA1 promoter activity. ABCA1 expression and cholesterol efflux strongly correlated with HIF-1β expression in hypoxic macrophages and in human atherosclerotic lesion macrophages.\",\n      \"method\": \"HIF-1 response element binding assay, ABCA1 promoter-reporter assay, constitutively active HIF-1α overexpression, ChIP (inferred), cholesterol efflux under hypoxia, human atherosclerotic lesion analysis\",\n      \"journal\": \"The international journal of biochemistry & cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — promoter binding and gain-of-function with in vivo correlation, single study\",\n      \"pmids\": [\"19828131\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"CXCL12 reduces ABCA1 expression and cholesterol efflux from macrophages via CXCR4→GSK3β phosphorylation→β-catenin Thr120 phosphorylation pathway. TCF21 directly stimulates ABCA1 transcription by binding to its promoter (confirmed by luciferase reporter and ChIP), and CXCL12 represses TCF21. Knockdown or inhibition of CXCR4 blocked CXCL12 effects on TCF21 and ABCA1 expression.\",\n      \"method\": \"Luciferase reporter assay, ChIP, siRNA knockdown (CXCR4), kinase inhibitors, protein phosphorylation assays, cholesterol efflux assay, in vivo lentiviral CXCL12 overexpression in Apoe-/- mice\",\n      \"journal\": \"Journal of lipid research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — ChIP plus reporter assay plus siRNA with in vivo confirmation\",\n      \"pmids\": [\"31662443\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ABCA1 regulates aqueous humor outflow and intraocular pressure via the caveolin-1/endothelial NO synthase (eNOS)/NO signaling pathway. ABCA1 upregulation in angular aqueous plexus (Schlemm's canal equivalent) cells decreases caveolin-1 expression and increases eNOS expression and NO production, reducing transendothelial resistance. In vivo intracameral injection of ABCA1 agonist GW3965 decreased IOP and increased conventional outflow facility.\",\n      \"method\": \"ABCA1 overexpression (lentivirus-ABCA1-shRNA or agonist GW3965), transendothelial electrical resistance measurement, eNOS/caveolin-1 protein expression, NO concentration measurement, in vivo intracameral injection, IOP measurement\",\n      \"journal\": \"Investigative ophthalmology & visual science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — gain and loss of function in cell model with in vivo confirmation, single study\",\n      \"pmids\": [\"32428234\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"ABCA1 mediates microparticle (MP) formation during HDL biogenesis. Using ABCA1 overexpression under inducible control and selective ABCA1 inactivation (probucol), MPs were shown to constitute approximately 30% of ABCA1-and apoA-I-mediated cholesterol efflux. Adding apoA-I markedly increases MP release. MPs contain flotillin-2 and CD63 but not apoA-I.\",\n      \"method\": \"Inducible ABCA1 expression system, probucol-mediated ABCA1 inhibition, methyl-β-cyclodextrin cholesterol depletion, MP characterization (size, markers), cholesterol efflux assay\",\n      \"journal\": \"Atherosclerosis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — inducible expression plus pharmacological inhibition in multiple cell types, single lab\",\n      \"pmids\": [\"28129550\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Caveolin-1 acts as a key promoter of ABCA1 endolysosomal trafficking identified by discovery proteomics. In APOE4 and AD models, greater caveolin-1 expression traps ABCA1 in lysosomes, causing oxysterol accumulation, mTORC1 activation, and cellular senescence. Cyclodextrin treatment reduced brain oxysterol levels, ABCA1 lysosome trapping, mTORC1 activation, and senescence markers in APOE4-TR mice.\",\n      \"method\": \"Unbiased proteomics (discovery), ABCA1 knockout cell lines and mouse models, APOE4-TR mice, iPSC-derived astrocytes, mTORC1 phosphorylation assay, senescence markers, cyclodextrin treatment\",\n      \"journal\": \"Molecular neurodegeneration\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — proteomics discovery with genetic and pharmacological validation in multiple models, single recent study\",\n      \"pmids\": [\"39901180\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ABCA1 is an ATP-hydrolyzing transmembrane flippase that translocates phospholipids from the cytoplasmic to the exofacial leaflet of the plasma membrane, creating membrane strain and exovesiculated lipid domains to which lipid-free apoA-I binds directly (via interaction with ABCA1 and membrane lipid domains) and solubilizes phospholipid and cholesterol to assemble nascent discoidal HDL particles; its expression is transcriptionally induced by LXR/RXR, RAR/RXR, HIF-1, and AMPK→LXRα pathways via DR4 and other promoter elements, while post-translationally ABCA1 protein stability is regulated by calpain-mediated degradation in early endosomes (retarded by apoA-I binding, α1-syntrophin, calmodulin, and LXRβ), by PLD2/diacylglycerol-dependent serine phosphorylation (triggered by unsaturated fatty acids), by cAMP/PKA-dependent phosphorylation (enhancing efflux), by OSBP sterol-binding domain-dependent destabilization, and by ARF6-dependent endolysosomal trapping; ABCA1 also functions as a signaling receptor activating JAK2/STAT3, PKA, PKC, and CDC42 pathways upon apoA-I binding, mediates phosphatidylserine exposure and microparticle formation, regulates beta-cell insulin secretion and hepatocyte insulin signaling through plasma membrane free cholesterol maintenance, and modulates neuroinflammation and apoE lipidation in the brain.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ABCA1 is an ATP-dependent phospholipid translocase that drives reverse cholesterol transport by flipping phospholipids from the cytoplasmic to the exofacial leaflet of the plasma membrane, creating cholesterol- and phospholipid-enriched domains that are solubilized by lipid-free apoA-I to generate nascent HDL particles [PMID:10918065, PMID:29305383, PMID:16500904]. Loss-of-function mutations in ABCA1 cause Tangier disease and familial HDL deficiency, characterized by near-absent plasma HDL and defective cellular cholesterol efflux [PMID:10525055, PMID:10533863]. ABCA1 transcription is induced by LXR/RXR and RAR/RXR heterodimers acting on a DR4 promoter element [PMID:10858438, PMID:14560020], while protein stability is regulated by cAMP/PKA-activating phosphorylation, PLD2/diacylglycerol-mediated destabilizing phosphorylation, calpain-dependent endosomal degradation restrained by apolipoprotein binding, and OSBP-dependent turnover [PMID:12454270, PMID:16118212, PMID:21835264, PMID:18450749]. Beyond lipid efflux, ABCA1 promotes phosphatidylserine exposure and apoptotic cell engulfment [PMID:10878804], modulates membrane lipid raft composition to suppress TLR4-driven macrophage inflammation [PMID:19797709], is required in pancreatic beta cells for cholesterol homeostasis and insulin secretion [PMID:17322896], controls hepatocyte plasma membrane free cholesterol for insulin/lipogenic signaling [PMID:28591582], and in astrocytes is specifically required for brain ApoE lipidation [PMID:23376685].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"The gene responsible for Tangier disease and familial HDL deficiency was unknown; identification of ABCA1 mutations in affected kindreds established it as the essential mediator of apolipoprotein-dependent cellular cholesterol efflux and HDL formation.\",\n      \"evidence\": \"Positional cloning, expression microarray, mutation detection in Tangier and familial HDL deficiency families, fibroblast cholesterol efflux assays\",\n      \"pmids\": [\"10525055\", \"10533863\", \"10535983\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of lipid transfer to apoA-I was unresolved\", \"Whether ABCA1 directly binds apoA-I was unknown\", \"Transcriptional regulation of ABCA1 was undefined\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"How ABCA1 physically engages apoA-I and moves lipids was unclear; cross-linking and co-IP demonstrated direct ABCA1–apoA-I binding, while echinocyte morphology and phospholipid redistribution assays established ABCA1 as a flippase that also exposes phosphatidylserine and promotes apoptotic cell engulfment.\",\n      \"evidence\": \"Chemical cross-linking, co-IP, confocal microscopy of overexpressing cells, prothrombinase and spin-label assays, phagocytosis assays in ABCA1-null and transfected macrophages\",\n      \"pmids\": [\"10918065\", \"10878804\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Enzymatic ATPase activity had not been directly measured on purified protein\", \"Structural basis of lipid translocation was unknown\", \"Whether phosphatidylserine exposure and cholesterol efflux are mechanistically separable was unresolved\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"The transcriptional control of ABCA1 was undefined; LXR/RXR heterodimers were shown to bind a DR4 element in the ABCA1 promoter, with oxysterols and retinoids cooperatively inducing expression, establishing the core sterol-responsive transcriptional axis.\",\n      \"evidence\": \"Reporter gene assays with DR4 mutagenesis, LXR/RXR cotransfection in macrophages, in vivo rexinoid pharmacology\",\n      \"pmids\": [\"10858438\", \"10968783\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Other nuclear receptors that might use the same element were not tested\", \"Post-translational regulation of ABCA1 was unexplored\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Whether post-translational phosphorylation regulates ABCA1 activity was unknown; cAMP/PKA signaling was shown to phosphorylate ABCA1 and promote cholesterol efflux, with Tangier cells failing to respond, linking kinase regulation directly to disease-relevant function.\",\n      \"evidence\": \"32P-phosphorylation assays with forskolin/H-89 in normal and Tangier fibroblasts, cholesterol efflux quantitation\",\n      \"pmids\": [\"12454270\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific phosphorylation sites were not mapped\", \"Whether other kinases contribute was unresolved\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Whether retinoid receptors independently regulate ABCA1 was unclear; ChIP demonstrated that RAR/RXR directly binds the same DR4 element as LXR/RXR, with RAR-knockout macrophages showing compensatory upregulation, establishing a parallel transcriptional input.\",\n      \"evidence\": \"Chromatin immunoprecipitation, RARγ-knockout macrophages, all-trans-retinoic acid treatment\",\n      \"pmids\": [\"14560020\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative physiological contribution of RAR vs. LXR pathways in vivo was not quantified\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Intracellular trafficking partners of ABCA1 were uncharacterized; syntaxin 13 and flotillin-1 were identified as direct ABCA1 interactors in lipid raft microdomains, with syntaxin 13 knockdown reducing ABCA1 protein and phospholipid efflux, linking phagosomal compartments to ABCA1 function.\",\n      \"evidence\": \"Co-IP, immunofluorescence, siRNA knockdown, detergent-resistant membrane fractionation in macrophages\",\n      \"pmids\": [\"15469992\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether syntaxin 13 acts in ABCA1 recycling vs. stabilization was not distinguished\", \"Probucol was separately shown to block ABCA1 plasma membrane translocation but upstream mechanism was unclear\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"How unsaturated fatty acids suppress ABCA1 was unknown; PLD2 activation by acyl-CoA derivatives was shown to generate diacylglycerols that promote destabilizing serine phosphorylation of ABCA1, defining a lipid-metabolic degradation pathway.\",\n      \"evidence\": \"PLD activity assays, PLD2 siRNA, phosphoserine analysis, acyl-CoA synthetase inhibitor\",\n      \"pmids\": [\"16118212\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific serine residues targeted were not identified\", \"Whether PLD2 pathway operates in vivo was untested\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Whether purified ABCA1 has intrinsic ATPase activity and what lipids regulate it was untested; reconstituted human ABCA1 showed robust ATPase activity preferentially stimulated by phosphatidylcholine and sphingomyelin and inhibited by cholesterol, confirming direct enzymatic function.\",\n      \"evidence\": \"Purification from Sf9 cells, liposome reconstitution, in vitro ATPase assay with defined lipid compositions\",\n      \"pmids\": [\"16500904\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of lipid selectivity was unresolved\", \"Whether ATPase rate correlates with translocation rate was not established\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Whether ABCA1 has physiological roles beyond HDL biogenesis was uncertain; beta-cell-specific Abca1 deletion impaired glucose-stimulated insulin secretion through altered cholesterol homeostasis, establishing a metabolic function independent of plasma HDL.\",\n      \"evidence\": \"Conditional beta-cell-specific knockout mice, glucose tolerance tests, in vitro insulin secretion, rosiglitazone rescue\",\n      \"pmids\": [\"17322896\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism linking cholesterol accumulation to secretory granule dysfunction was not defined\", \"Whether human beta-cell ABCA1 loss phenocopies was unknown\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"ABCA1 intracellular trafficking dynamics were poorly characterized; clathrin/Rab5-mediated endocytosis and Rab4-mediated recycling were defined, with ~30% of endocytosed ABCA1 returning to the surface, and OSBP was identified as a sterol-dependent negative regulator of ABCA1 protein half-life.\",\n      \"evidence\": \"Tagged ABCA1 constructs with Rab/clathrin inhibition; OSBP RNAi and domain mutagenesis with protein half-life measurements\",\n      \"pmids\": [\"19170766\", \"18450749\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How OSBP mechanistically targets ABCA1 for degradation was unresolved\", \"Whether Rab4-mediated recycling is the dominant recycling route was not confirmed\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Whether ABCA1 regulates innate immunity was unknown; ABCA1 knockout macrophages showed enhanced TLR4 signaling and inflammatory cytokine production, demonstrating that sterol efflux modulates membrane lipid organization to restrain inflammatory responses.\",\n      \"evidence\": \"ABCA1/ABCG1 macrophage knockout mice, TLR4 pathway analysis, cytokine measurements\",\n      \"pmids\": [\"19797709\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific membrane lipid species mediating TLR4 activation were not identified\", \"Whether anti-inflammatory function is separable from cholesterol efflux was unclear\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"How ABCA1 is degraded and how apolipoprotein binding stabilizes it were undefined; calpain was identified as the protease degrading ABCA1 in early endosomes, with apolipoprotein binding conferring calpain resistance, and α1-syntrophin/calmodulin/LXRβ retarding degradation.\",\n      \"evidence\": \"Calpain inhibitor studies, endosomal fractionation, interaction protein analysis, in vivo pharmacology\",\n      \"pmids\": [\"21835264\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Calpain cleavage site(s) on ABCA1 were not mapped\", \"Whether calpain inhibition is a viable therapeutic strategy long-term was untested\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Whether ABCA1 functions as a signaling receptor was unclear; apoA-I binding to ABCA1 was shown to activate JAK2/STAT3, PKA, CDC42, and PKC pathways, with distinct downstream effects on lipid efflux, ABCA1 stabilization, and anti-inflammatory signaling.\",\n      \"evidence\": \"Signaling pathway inhibitors, co-IP, siRNA in macrophages\",\n      \"pmids\": [\"21920460\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Most pathways documented by single method per pathway\", \"Direct phosphorylation of ABCA1 by these kinases not demonstrated for all\", \"Whether signaling is cell-type-specific was untested\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Cell-type-specific roles of ABCA1 in the brain were undefined; astrocyte-specific ABCA1 deletion reduced cortical ApoE levels while whole-brain deletion caused neuroinflammation and neuronal death, establishing astrocyte ABCA1 as the primary source of lipidated brain ApoE.\",\n      \"evidence\": \"Cell-type-specific conditional knockout mice (astrocyte, neuronal, whole-brain), ApoE measurement, MAPK/TNFα assays, phagocytosis\",\n      \"pmids\": [\"23376685\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether neuronal ABCA1 has cell-autonomous protective functions was not fully resolved\", \"Mechanism linking ABCA1 loss to microglial dysfunction was not defined\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"How macrophages upregulate ABCA1 upon encountering apoptotic cells was unknown; a BAI1→ELMO1→Rac1 signaling cascade triggered by apoptotic cell phosphatidylserine was shown to induce ABCA1 independently of LXR sterol sensing, linking efferocytosis to cholesterol efflux.\",\n      \"evidence\": \"BAI1/ELMO1/Rac1 knockout macrophages, ABCA1 induction assays, high-fat diet in vivo model\",\n      \"pmids\": [\"26075824\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream transcription factor activated by Rac1 to induce ABCA1 was not identified\", \"Whether this pathway operates in non-macrophage cell types was untested\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Whether ABCA1 mediates cholesterol efflux partly through microparticle release and how hepatocyte ABCA1 affects insulin signaling were unresolved; ABCA1-dependent microparticles were shown to account for ~30% of cholesterol efflux, and hepatocyte-specific ABCA1 knockout revealed selective insulin resistance through impaired plasma membrane free cholesterol and Akt signaling.\",\n      \"evidence\": \"Inducible ABCA1 expression with particle characterization; hepatocyte-specific KO mice with insulin signaling and cholesterol fractionation\",\n      \"pmids\": [\"28129550\", \"28591582\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism of microparticle budding was not defined\", \"Whether microparticle-mediated efflux is relevant in vivo was not established\", \"How plasma membrane cholesterol specifically controls Akt phosphorylation was unclear\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"How ApoE4 genotype impairs ABCA1 function was mechanistically undefined; ApoE4 was shown to upregulate ARF6, trapping ABCA1 in late endosomes and reducing its recycling, cholesterol efflux, ApoE lipidation, and Aβ degradation capacity.\",\n      \"evidence\": \"ARF6 expression analysis, endosomal fractionation, ABCA1 trafficking assays, ApoE4-TR mice, human CSF\",\n      \"pmids\": [\"31641056\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How ApoE4 specifically induces ARF6 was not determined\", \"Whether restoring ABCA1 trafficking rescues Aβ clearance in vivo long-term was untested\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Whether ABCA1 partners with myelin-associated proteins was unknown; PMP22 was identified as a direct ABCA1 interactor in Schwann cells, with bidirectional knockout experiments showing mutual dependence for plasma membrane localization and cholesterol efflux.\",\n      \"evidence\": \"Reciprocal co-IP from Schwann cell/nerve lysates, PMP22-KO and ABCA1-KO mice, cholesterol efflux, electrophysiology\",\n      \"pmids\": [\"31061090\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of PMP22–ABCA1 interaction was not defined\", \"Relevance to Charcot-Marie-Tooth disease pathogenesis was not tested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"How oxysterol accumulation in APOE4/AD contexts disrupts ABCA1 was mechanistically unclear; caveolin-1 was identified as a cholesterol sensor that promotes ABCA1 lysosomal trapping, leading to mTORC1 activation and cellular senescence, with cyclodextrin rescue in APOE4-TR mice.\",\n      \"evidence\": \"Unbiased proteomics, ABCA1-KO cell lines, APOE4-TR mice, iPSC-derived astrocytes, mTORC1 assays, cyclodextrin rescue, human brain validation\",\n      \"pmids\": [\"39901180\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct caveolin-1–ABCA1 binding interface not mapped\", \"Whether mTORC1 activation is the primary pathogenic effector or a correlate of lysosomal trapping is unresolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"A high-resolution structural model of full-length ABCA1 in complex with apoA-I and lipid substrates is needed to explain the mechanism of phospholipid translocation, apoA-I docking geometry, and disease-causing mutation effects; additionally, how ABCA1's translocase activity, signaling functions, and microparticle generation are mechanistically coupled or separable remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No full atomic structure of ABCA1–apoA-I complex with lipid substrates\", \"Calpain cleavage sites and phosphorylation sites not comprehensively mapped\", \"Whether signaling functions (JAK2/STAT3, CDC42) require translocase activity is untested\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140657\", \"supporting_discovery_ids\": [12, 26]},\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [0, 3, 4, 12, 26]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [3, 12, 26]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [12]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 3, 10, 26, 28]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [14, 18, 27, 30]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [23]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-382551\", \"supporting_discovery_ids\": [0, 1, 3, 12, 26]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0, 1, 13, 25]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [5, 6, 8, 24]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [7, 19, 22, 29]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [16]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [14, 23]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"APOA1\",\n      \"STX13\",\n      \"FLOT1\",\n      \"PLD2\",\n      \"OSBP\",\n      \"PMP22\",\n      \"CAV1\",\n      \"SNTA1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"mechanistic_narrative\": \"ABCA1 is an ATP-hydrolyzing phospholipid flippase that translocates phospholipids from the inner to the outer leaflet of the plasma membrane, creating exovesiculated lipid domains to which lipid-free apoA-I binds and solubilizes phospholipid and cholesterol to assemble nascent discoidal HDL particles [PMID:17604270, PMID:10918065]. Its ATPase activity is stimulated by choline-containing phospholipids and inhibited by cholesterol [PMID:16500904], and the protein cycles between the plasma membrane and early endosomes via clathrin/Rab5-dependent endocytosis and Rab4-dependent recycling, with calpain-mediated degradation in endosomes serving as a major turnover mechanism retarded by apoA-I binding [PMID:19170766, PMID:21835264]. Transcription is driven by LXR/RXR and RAR/RXR heterodimers acting on a DR4 promoter element, with additional regulation by HIF-1, AMPK→LXRα, TCF21, and BAI1→ELMO1→Rac1 pathways, while post-translational stability is modulated by PLD2/diacylglycerol-dependent serine phosphorylation, OSBP sterol-binding-domain-dependent destabilization, and cAMP/PKA-dependent phosphorylation that enhances efflux [PMID:10858438, PMID:14560020, PMID:27343431, PMID:16118212, PMID:18450749, PMID:12454270]. Loss-of-function mutations in ABCA1 cause Tangier disease and familial HDL deficiency, and cell-type-specific deletion in pancreatic β-cells or hepatocytes disrupts cholesterol-dependent insulin secretion and insulin signaling, respectively, while brain ABCA1 deficiency reduces apoE lipidation and exacerbates amyloid deposition [PMID:10533863, PMID:17322896, PMID:28591582, PMID:16207713].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Identification of ABCA1 as the gene mutated in Tangier disease and familial HDL deficiency resolved a decades-old question about the molecular basis of apolipoprotein-mediated cholesterol efflux and HDL formation.\",\n      \"evidence\": \"Gene expression microarrays, genetic mapping, mutation sequencing in patient fibroblasts, and functional validation via siRNA/overexpression across multiple independent labs\",\n      \"pmids\": [\"10525055\", \"10431236\", \"10431237\", \"10431238\", \"10533863\", \"10535983\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which ABCA1 moves lipids was unknown\", \"Direct protein–apoA-I interaction not yet shown\", \"Transcriptional regulation undefined\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Demonstration that apoA-I binds directly to ABCA1 at the cell surface and that ABCA1 expression induces phospholipid translocation and phosphatidylserine exposure established it as a lipid flippase generating exofacial membrane strain.\",\n      \"evidence\": \"Chemical cross-linking, co-immunoprecipitation, echinocyte morphology in ABCA1-overexpressing cells, prothrombinase assay and spin-labeled phospholipid transbilayer redistribution in knockout and transfected cells\",\n      \"pmids\": [\"10918065\", \"10878804\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No purified-protein ATPase data yet\", \"Structural basis of apoA-I–ABCA1 interaction unknown\", \"Whether flippase activity is sufficient for HDL assembly unresolved\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Discovery that LXR/RXR heterodimers directly activate the ABCA1 promoter via a DR4 element established the sterol-sensing transcriptional circuit controlling reverse cholesterol transport.\",\n      \"evidence\": \"Promoter-reporter assays with site-directed mutagenesis of DR4 element, LXR/RXR co-transfection, rexinoid pharmacology in mice\",\n      \"pmids\": [\"10858438\", \"10968783\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Other transcription factors acting on ABCA1 promoter unknown\", \"Post-transcriptional regulation not addressed\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Identification of cAMP/PKA-dependent phosphorylation of ABCA1 as an activating signal for cholesterol efflux revealed a rapid post-translational regulatory mechanism distinct from transcriptional control.\",\n      \"evidence\": \"Radiolabeled phosphorylation assay with PKA inhibitor H-89 and genetic controls from Tangier disease and familial HDL deficiency fibroblasts\",\n      \"pmids\": [\"12454270\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific phosphorylation sites on ABCA1 not mapped\", \"Kinase-phosphatase balance not characterized\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"RAR/RXR was shown to directly activate ABCA1 via the same DR4 element as LXR/RXR, expanding the regulatory network to include retinoid signaling and demonstrating receptor redundancy at this promoter element.\",\n      \"evidence\": \"ChIP in macrophages, RARγ-knockout mouse macrophages showing compensatory RARα induction\",\n      \"pmids\": [\"14560020\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological contexts where RAR dominates over LXR unclear\", \"Combinatorial versus competitive binding not resolved\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Identification of syntaxin 13 and flotillin-1 as direct ABCA1 interaction partners in lipid raft microdomains established that ABCA1 operates within a defined membrane trafficking complex, and probucol was shown to block ABCA1 translocation to the plasma membrane.\",\n      \"evidence\": \"Reciprocal co-immunoprecipitation, siRNA knockdown of syntaxin 13 reducing ABCA1 levels and efflux, probucol trafficking assays with Tangier fibroblast controls\",\n      \"pmids\": [\"15469992\", \"15514211\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How syntaxin 13 controls ABCA1 stability versus trafficking not distinguished\", \"Probucol's direct molecular target on ABCA1 not identified\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Unsaturated fatty acids were shown to destabilize ABCA1 through PLD2-generated diacylglycerol and serine phosphorylation, revealing a lipid-sensing post-translational degradation pathway.\",\n      \"evidence\": \"PLD2 siRNA rescue, triacsin C inhibitor, diacylglycerol analog experiments with phosphorylation and protein stability readouts\",\n      \"pmids\": [\"16118212\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific serine residues targeted not identified\", \"Whether PLD2 pathway operates in vivo not tested\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Reconstitution of purified ABCA1 into liposomes provided direct biochemical proof of intrinsic ATPase activity stimulated by phospholipids and inhibited by cholesterol, confirming the flippase hypothesis at the protein level.\",\n      \"evidence\": \"Purified human ABCA1 from Sf9 cells, liposome ATPase assay with defined lipid compositions\",\n      \"pmids\": [\"16500904\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No direct lipid translocation demonstrated with purified protein\", \"Structure of ABCA1 not solved\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Brain ABCA1 deficiency was shown to reduce soluble apoE and increase amyloid deposition in APP transgenic mice, and HIV-1 Nef was found to bind and impair ABCA1, establishing disease-relevant consequences of ABCA1 dysfunction beyond HDL metabolism.\",\n      \"evidence\": \"ABCA1-KO × APP23 crosses with amyloid staining and apoE fractionation; Nef–ABCA1 co-IP with efflux and virion cholesterol assays\",\n      \"pmids\": [\"16207713\", \"17076584\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ABCA1 effects on amyloid are solely via apoE lipidation not resolved\", \"In vivo relevance of Nef–ABCA1 interaction in HIV patients not confirmed\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"A detailed mechanistic model of nascent HDL assembly was established: ABCA1-driven phospholipid translocation creates curved exovesiculated membrane domains from which apoA-I spontaneously solubilizes discoidal particles, and separately, β-cell-specific ABCA1 knockout revealed a role in insulin secretion via islet cholesterol homeostasis.\",\n      \"evidence\": \"Systematic lipid efflux kinetics and HDL particle composition analysis; conditional β-cell ABCA1 KO mice with glucose tolerance and insulin secretion assays\",\n      \"pmids\": [\"17604270\", \"17322896\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and kinetics of apoA-I–membrane domain interaction not fully defined\", \"Whether β-cell phenotype is relevant to human diabetes from ABCA1 variants not established\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"ABCA1 endocytic recycling via clathrin/Rab5 internalization and Rab4 return was mapped, and OSBP was identified as a sterol-sensing negative regulator of ABCA1 protein stability, integrating trafficking and post-translational control.\",\n      \"evidence\": \"Tagged ABCA1 constructs with dominant-negative Rabs and clathrin inhibition; OSBP siRNA with cycloheximide chase and domain mutants\",\n      \"pmids\": [\"19170766\", \"18450749\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How OSBP sterol binding leads to ABCA1 degradation mechanistically unclear\", \"Relative contribution of recycling versus de novo synthesis to steady-state ABCA1 not quantified\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Macrophage ABCA1 was linked to anti-inflammatory function through TLR signaling modulation, HIF-1 was identified as a direct transcriptional activator under hypoxia, and the LRP1→cPLA2→LXR pathway was shown to control ABCA1 expression, substantially expanding the upstream regulatory network.\",\n      \"evidence\": \"ABCA1/ABCG1-KO macrophages with TLR/cytokine readouts; HIF-1 response element binding and promoter assays; LRP1-KO cells with cPLA2 signaling analysis\",\n      \"pmids\": [\"19797709\", \"19828131\", \"19718435\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"ABCA1-specific versus ABCG1-specific anti-inflammatory contributions not fully separated\", \"HIF-1 regulation of ABCA1 not independently replicated\", \"LRP1 pathway is single-study evidence\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Calpain was identified as the protease responsible for ABCA1 degradation in early endosomes, with apoA-I binding and interactors (α1-syntrophin, LXRβ, calmodulin) protecting ABCA1 from calpain, and apoA-I/ABCA1 signaling via JAK2/STAT3, PKA, CDC42, and PKC was documented.\",\n      \"evidence\": \"Calpain inhibitor pharmacology with subcellular fractionation and in vivo validation; kinase inhibitors and dominant-negative constructs for signaling pathway dissection\",\n      \"pmids\": [\"21835264\", \"21920460\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Calpain cleavage site on ABCA1 not mapped\", \"Relative importance of individual signaling arms not established in vivo\", \"JAK2/STAT3 pathway evidence largely compiled from multiple prior studies\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"miR-33a was shown to suppress ABCA1 expression in islets and reduce insulin secretion through cholesterol accumulation, providing a post-transcriptional regulatory axis linking metabolic microRNA networks to β-cell function.\",\n      \"evidence\": \"Adenoviral miR-33a overexpression and inhibition in human/mouse islets with cholesterol depletion rescue\",\n      \"pmids\": [\"22315319\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo relevance of miR-33a–ABCA1 axis to type 2 diabetes not demonstrated\", \"Other miR-33a targets that could contribute not excluded\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"A sterol-independent transcriptional induction pathway was discovered: apoptotic cells activate BAI1→ELMO1→Rac1 to upregulate ABCA1 independently of LXR, linking efferocytosis directly to cholesterol efflux capacity.\",\n      \"evidence\": \"Primary macrophages from BAI1/ELMO1/Rac1-KO mice, in vivo high-fat diet model with aortic root amyloid and lipid profiling\",\n      \"pmids\": [\"26075824\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream transcription factor activated by Rac1 to drive ABCA1 not identified\", \"Whether this pathway is relevant in non-macrophage cell types unknown\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"AMPK was placed upstream of LXRα in ABCA1 transcriptional activation, with ChIP confirming LXRα binding to the ABCA1 promoter upon AMPK activation, connecting energy-sensing to cholesterol efflux.\",\n      \"evidence\": \"AMPK siRNA/overexpression, LXRα siRNA epistasis, ChIP, pharmacological activators in human macrophages\",\n      \"pmids\": [\"27343431\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How AMPK activates LXRα (direct phosphorylation vs indirect) not resolved\", \"In vivo relevance in atherosclerosis models not tested\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"TRAK2 was identified as a negative regulator of LXR-mediated ABCA1 transcription, hepatocyte ABCA1 was shown essential for maintaining plasma membrane cholesterol and insulin signaling, and ABCA1-dependent microparticle release was quantified as ~30% of total cholesterol efflux.\",\n      \"evidence\": \"TRAK2 siRNA with ChIP showing increased LXR promoter binding; hepatocyte-specific ABCA1-KO with Akt phosphorylation and SREBP-1c readouts; inducible ABCA1 expression with MP characterization\",\n      \"pmids\": [\"28655204\", \"28591582\", \"28129550\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which TRAK2 inhibits LXR promoter access unknown\", \"Relative importance of MP release versus direct lipid transfer to apoA-I in vivo not established\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"ApoE4-driven ARF6 overexpression was shown to trap ABCA1 in late endosomes, impairing cholesterol efflux and Aβ degradation, and the CXCL12→CXCR4→GSK3β→β-catenin→TCF21 pathway was identified as a transcriptional repressor of ABCA1, while PMP22 was found to physically interact with ABCA1 and facilitate its plasma membrane localization in Schwann cells.\",\n      \"evidence\": \"ARF6 trafficking assays in ApoE4-TR mice; ChIP and reporter assays for TCF21/CXCL12 pathway with in vivo lentiviral overexpression; reciprocal co-IP from Schwann cell and nerve lysates with PMP22-KO and ABCA1-KO mice\",\n      \"pmids\": [\"31641056\", \"31662443\", \"31061090\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ARF6-mediated trapping is reversible therapeutically not established\", \"TCF21 as ABCA1 activator demonstrated only in macrophages\", \"PMP22–ABCA1 interaction domain not mapped\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"ABCA1 was linked to intraocular pressure regulation through modulation of caveolin-1/eNOS/NO signaling in Schlemm's canal endothelium, extending its functional repertoire beyond lipid metabolism.\",\n      \"evidence\": \"Lentiviral ABCA1 manipulation, transendothelial resistance, eNOS/NO measurement, in vivo intracameral GW3965 injection with IOP measurement\",\n      \"pmids\": [\"32428234\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single study without independent replication\", \"Whether cholesterol efflux per se mediates eNOS derepression or a distinct ABCA1 mechanism operates is unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Caveolin-1 was identified by unbiased proteomics as a promoter of ABCA1 endolysosomal trapping, linking APOE4-associated ABCA1 mislocalization to oxysterol accumulation, mTORC1 activation, and cellular senescence.\",\n      \"evidence\": \"Discovery proteomics, ABCA1-KO cells and mice, APOE4-TR mice, iPSC-derived astrocytes, cyclodextrin rescue\",\n      \"pmids\": [\"39901180\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single recent study awaiting independent replication\", \"Whether caveolin-1 directly binds ABCA1 or acts indirectly through membrane domains not determined\", \"Therapeutic relevance of cyclodextrin in humans unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"A high-resolution structure of full-length ABCA1 in complex with apoA-I and/or lipid substrates is needed to explain the molecular basis of phospholipid flippase selectivity, cholesterol inhibition, and the coupling between ATP hydrolysis and lipid translocation.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No atomic-resolution structure of ABCA1 in lipid-bound or apoA-I-bound state\", \"Direct lipid translocation has not been demonstrated with purified reconstituted protein\", \"In vivo contributions of microparticle release versus direct apoA-I lipidation not quantified\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140657\", \"supporting_discovery_ids\": [11, 12]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [2, 11, 12]},\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [0, 1, 3, 11, 12]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [19]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 2, 8, 12, 14, 26]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [14, 18, 25, 33]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [14, 32]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-382551\", \"supporting_discovery_ids\": [0, 1, 2, 11, 12, 13, 24]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [4, 5, 11, 13, 20, 24]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [6, 19, 22]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [17]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [8, 14, 18, 25]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [4, 7, 22, 23, 30]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [1, 27, 28]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"APOA1\",\n      \"STX13\",\n      \"FLOT1\",\n      \"PMP22\",\n      \"OSBP\",\n      \"PLD2\",\n      \"CAV1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}