{"gene":"ARRB1","run_date":"2026-06-09T22:02:44","timeline":{"discoveries":[{"year":2014,"finding":"ARRB1 interacts with BECN1/Beclin 1 and PIK3C3/Vps34 (two major components of the BECN1 autophagic core complex) under ischemic (OGD) but not normal conditions in neurons, and loss of ARRB1 impairs the BECN1-PIK3C3 interaction and reduces PIK3C3 kinase activity, thereby suppressing autophagosome formation and promoting neuronal apoptosis/necrosis in cerebral ischemia.","method":"Co-immunoprecipitation, Arrb1 knockout mice, in vitro OGD model, PIK3C3 kinase activity assay","journal":"Autophagy","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, KO mouse with defined cellular phenotype, kinase activity assay, multiple orthogonal methods in one study","pmids":["24988431"],"is_preprint":false},{"year":2011,"finding":"Nicotine induces nuclear translocation of ARRB1 in NSCLC cells; nuclear ARRB1 binds E2F transcription factors and, together with EP300 and acetylated histone H3, occupies promoters of E2F-regulated survival/proliferative genes (CDC6, TYMS, BIRC5), driving their transcriptional activation and mediating nicotine's mitogenic and antiapoptotic effects.","method":"Nuclear fractionation/immunofluorescence, shRNA knockdown, chromatin immunoprecipitation (ChIP), co-immunoprecipitation, qRT-PCR, human NSCLC tumors","journal":"Journal of the National Cancer Institute","confidence":"High","confidence_rationale":"Tier 2 / Strong — nuclear localization by fractionation, ChIP on cell lines and primary tumors, reciprocal Co-IP, shRNA rescue; multiple orthogonal methods in one study","pmids":["21212384"],"is_preprint":false},{"year":2014,"finding":"Nuclear ARRB1 in prostate cancer cells regulates HIF1A transcriptional activity under normoxic conditions (pseudohypoxia) by controlling the expression of succinate dehydrogenase A (SDHA) and fumarate hydratase (FH), thereby shifting cellular metabolism toward aerobic glycolysis; this was established by genome-wide chromatin binding mapping (ChIP-seq) combined with gene expression profiling.","method":"Genome-wide ChIP-seq (first for an endocytic adaptor), gene expression profiling, in vitro and in vivo models","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — genome-wide ChIP-seq with gene expression profiling, in vitro and in vivo validation; multiple orthogonal methods","pmids":["24837709"],"is_preprint":false},{"year":2019,"finding":"ARRB1 interacts with GDF15 precursor (pro-GDF15) and facilitates its transportation to the Golgi apparatus for cleavage and maturation; loss of ARRB1 impairs this process, reduces mature GDF15, and accelerates NASH, while re-expression of ARRB1 together with pro-GDF15 overexpression is synergistically protective.","method":"Co-immunoprecipitation, Arrb1-KO mice, HFD/MCD NASH models, in vitro and in vivo rescue experiments","journal":"Journal of hepatology","confidence":"High","confidence_rationale":"Tier 2 / Strong — Co-IP identifying interaction, KO mice with defined phenotype, in vivo and in vitro rescue; multiple orthogonal methods","pmids":["31857195"],"is_preprint":false},{"year":2019,"finding":"ARRB1 promotes NOTCH1 ubiquitination and degradation in T-ALL cells through simultaneous interactions with NOTCH1 and the E3 ubiquitin ligase DTX1, acting as a tumor suppressor; this function is suppressed by oncomiR miR-223 which targets the 3'-UTR of ARRB1.","method":"Co-immunoprecipitation, ubiquitination assay, exogenous ARRB1 expression, T-ALL xenograft models, luciferase 3'-UTR reporter","journal":"Cancer research","confidence":"High","confidence_rationale":"Tier 2 / Strong — Co-IP showing trimeric complex, ubiquitination assay, in vivo xenograft, 3'-UTR reporter; multiple orthogonal methods","pmids":["31822496"],"is_preprint":false},{"year":2021,"finding":"ARRB1 interacts with HBx and the autophagic scaffold protein MAP1LC3/LC3, promoting autophagic flux and autophagosome formation; this ARRB1-mediated autophagy drives cell cycle progression by maintaining CDK2 phosphorylation and CDK2-CCNE1 complex activity, thereby promoting G1/S transition in HBV-related hepatocellular carcinogenesis.","method":"Co-immunoprecipitation, ARRB1 knockdown/knockout, autophagy inhibitor (3-MA), ATG5/ATG7 siRNA, cell cycle analysis, CDK2 kinase assay, mouse HCC models","journal":"Autophagy","confidence":"High","confidence_rationale":"Tier 2 / Strong — Co-IP of trimeric complex, multiple genetic perturbations, in vivo mouse models, kinase activity assay; multiple orthogonal methods","pmids":["33866937"],"is_preprint":false},{"year":2020,"finding":"ARRB1 directly interacts with ASK1 in hepatocytes and inhibits TRAF6-mediated Lysine 6-linked polyubiquitination of ASK1, preventing ASK1 activation and downstream signaling during hepatic ischemia/reperfusion injury; inhibition of ASK1 abolished the disruptive effect of ARRB1 deficiency, confirming ASK1 as a required effector of ARRB1 function.","method":"Co-immunoprecipitation, ARRB1 hepatocyte-specific overexpression, Arrb1-KO mice, ASK1 inhibitor rescue, ubiquitination assay","journal":"Journal of cellular and molecular medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — Co-IP, ubiquitination assay, KO and overexpression mouse models with epistasis rescue; multiple orthogonal methods","pmids":["32445435"],"is_preprint":false},{"year":2024,"finding":"ARRB1 directly binds phosphorylated eIF2α (p-eIF2α) and eIF2α, as shown by co-immunoprecipitation, and this interaction inhibits ER stress signaling (p-eIF2α-ATF4-CHOP axis) and downstream apoptosis (cleaved caspase-3) in APAP-induced hepatotoxicity.","method":"Co-immunoprecipitation, ARRB1-KO mice, ARRB1 overexpression in hepatic cell lines and primary hepatocytes, Western blot for ER stress markers","journal":"Cell biology and toxicology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP identifying direct binding, KO mouse and OE rescue, single lab with two orthogonal methods","pmids":["38252352"],"is_preprint":false},{"year":2021,"finding":"ARRB1 knockout in bladder cancer stem cell-like cells decreases glycolytic rate and induces metabolic reprogramming toward oxidative phosphorylation by increasing mitochondrial pyruvate carrier MPC1 protein levels and reducing GLUT1 protein levels and glucose uptake; ARRB1 overexpression in KO cells reverses this phenotype.","method":"ARRB1 KO and re-expression, Seahorse metabolic flux assay, glucose uptake assay, Western blot for MPC1 and GLUT1, spheroid formation","journal":"Cancers","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO with defined metabolic phenotype plus rescue experiment and multiple metabolic readouts, single lab","pmids":["33920080"],"is_preprint":false},{"year":2017,"finding":"EP4 receptor activation by PGE2 upregulates β-arrestin1 (ARRB1), which in turn scaffolds PI3K/Akt signaling to protect colonic mucosal integrity; ARRB1-deficient mice show markedly downregulated PI3K and p-Akt expression during DSS-induced colitis.","method":"Arrb1-KO mice, DSS colitis model, siRNA knockdown in HCT116 cells, Western blot for PI3K/p-Akt, PGE2 treatment","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO mouse with defined signaling phenotype and in vitro siRNA validation, single lab","pmids":["28432343"],"is_preprint":false},{"year":2021,"finding":"ET-1 activates ETA/ETB receptors to trigger mesothelial-to-mesenchymal transition (MMT) via β-arrestin1-dependent MAPK and NF-kB pathways; silencing of β-arrestin1 impairs ET-1-induced MC proliferation, upregulation of mesenchymal markers (fibronectin, α-SMA, N-cadherin, vimentin), NF-kB-dependent Snail activity, and SOC transmesothelial migration.","method":"β-arrestin1 siRNA silencing, ETA/ETB receptor blockade, Western blot, migration/invasion assays","journal":"Frontiers in cell and developmental biology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — silencing with defined signaling phenotype, receptor blockade epistasis, single lab, no reconstitution","pmids":["34926453"],"is_preprint":false},{"year":2025,"finding":"P300 mediates lactylation of ARRB1 at lysine 195 following subarachnoid hemorrhage, increasing ARRB1 protein expression and upregulating S100A9, which promotes mitochondrial dysfunction and neuronal apoptosis; a K195R mutation abolishes this effect, and P300 knockdown is rescued by ARRB1 overexpression.","method":"Lactylome analysis, co-immunoprecipitation, K195R point mutant, P300 knockdown/overexpression rescue, co-immunofluorescence, mitochondrial function assays (MMP, ROS, ATP, OCR), TUNEL/flow cytometry","journal":"Neurochemical research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — site-specific mutant abolishes effect, writer identified (P300), multiple functional readouts, single lab","pmids":["40445496"],"is_preprint":false},{"year":2025,"finding":"ARRB1 is identified as an essential adaptor for patchouli alcohol (PA)-induced autophagic cell death in NSCLC; PA specifically disrupts the GNAI1-ARRB1 protein-protein interaction (confirmed by DARTS, CETSA, molecular docking), and loss of ARRB1 abolishes downstream inhibition of ERK/JAK2-STAT3/mTOR pro-survival pathways.","method":"DARTS, CETSA, molecular docking, Co-IP, ARRB1 knockdown, autophagy flux assays, in vivo xenograft","journal":"International journal of biological sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple target-engagement methods (DARTS, CETSA) plus functional KD, single lab","pmids":["42088441"],"is_preprint":false},{"year":2025,"finding":"ARRB1 nuclear translocation in lung epithelial cells is induced by simulated space radiation and/or microgravity via changes in intracellular calcium concentration, which promotes CAMK2G-ARRB1 interaction; nuclear ARRB1 then enhances CA9 transcriptional activity to facilitate malignant transformation.","method":"Co-immunoprecipitation (CAMK2G-ARRB1), nuclear fractionation/imaging, calcium manipulation, CA9 transcriptional reporter, malignant transformation assays","journal":"NPJ microgravity","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP identifies interaction, nuclear localization directly measured, transcriptional reporter, single lab","pmids":["41339621"],"is_preprint":false},{"year":2025,"finding":"ARRB1 transcriptionally activates NPAS2 by binding to sites within the NPAS2 promoter region; this ARRB1-NPAS2 axis promotes malignant behaviors and glycolysis in lung adenocarcinoma cells, as NPAS2 knockdown effects are partially restored by ARRB1 overexpression.","method":"ChIP, promoter-binding assay, gain/loss-of-function, Seahorse OCR, glycolytic enzyme expression, rescue experiments","journal":"Clinical and experimental pharmacology & physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP confirms promoter binding, epistasis rescue experiment, single lab","pmids":["38584327"],"is_preprint":false},{"year":2024,"finding":"EHMT2 epigenetically suppresses ARRB1 transcription by binding the ARRB1 promoter and depositing H3K9me2 modification; reduced ARRB1 in turn fails to inhibit the Hedgehog pathway (GLI1, PTCH1), promoting OSCC cancer stem cell properties; ARRB1 overexpression counteracts EHMT2-driven Hedgehog activation.","method":"ChIP, lentiviral EHMT2 silencing, ARRB1 overexpression rescue, sphere formation assays, Western blot for H3K9me2/GLI1/PTCH1","journal":"Molecular biotechnology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP identifies H3K9me2 at ARRB1 promoter, rescue experiment, single lab","pmids":["38573544"],"is_preprint":false},{"year":2024,"finding":"ARRB1 interacts with Beclin 1 (BECN1) in nucleus pulposus cells, and ARRB1 knockdown suppresses formation of the Beclin1-PIK3C3 core complex, impairing autophagic flux; ARRB1 overexpression promotes autophagy, reduces extracellular matrix degradation and apoptosis, and delays IVDD progression in rats.","method":"Co-immunoprecipitation (ARRB1-Beclin1), lentiviral shRNA/OE, LC3-II/I ratio, autophagic flux assay, 3-MA autophagy inhibitor, in vivo rat IVDD model","journal":"Biochimica et biophysica acta. Molecular cell research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP, autophagy flux assay, in vivo model; single lab, replicates prior BECN1 interaction data","pmids":["38838859"],"is_preprint":false},{"year":2002,"finding":"The arrestin splice variant p44 (Arr1-370A) and truncated Arr(3-367) bind not only phosphorylated active rhodopsin but also inactive phosphorylated rhodopsin and opsin, making them membrane-bound in the dark (unlike full-length arrestin); upon photoexcitation these short arrestins are handed over from inactive to active phosphorylated rhodopsin and quench Gt activation on a subsecond timescale.","method":"Size exclusion chromatography, biophysical membrane-binding assay, G-protein activation (Gt) quenching assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with biophysical assays, mechanistic detail on binding selectivity and kinetics; multiple orthogonal methods in single rigorous study","pmids":["12194979"],"is_preprint":false},{"year":2022,"finding":"In rod photoreceptors lacking Arr1 (arrestin), PP2A deficiency accelerates retinal degeneration and further reduces maximal rod photoresponse amplitude; this genetic epistasis demonstrates that PP2A-mediated rhodopsin dephosphorylation acts in the same pathway as Arr1-mediated receptor deactivation, and that both are required for rod photoreceptor viability.","method":"Genetic double-knockout (Arr1-/- × PP2A Cα rod-specific KO), retinal histology, ex vivo electroretinography","journal":"Investigative ophthalmology & visual science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic epistasis with ERG functional readout, single lab","pmids":["35861670"],"is_preprint":false},{"year":2025,"finding":"Cryo-EM structures of mGluR8 complexed with β-arrestin1 reveal transducer-specific active states of mGluR8; single-molecule FRET shows β-arr1 stabilizes active mGluR8 conformations; mGluRs couple to β-arr1 with 2:1 or 2:2 stoichiometry via combined 'tail' and 'core' interactions; molecular dynamics supports a steric desensitization mechanism involving interactions with both subunits and the lipid bilayer.","method":"Cryo-EM structure determination, single-molecule pulldown assay, single-molecule FRET, molecular dynamics simulations, combinatorial mutagenesis","journal":"bioRxiv","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structure plus smFRET plus MD simulations plus mutagenesis; multiple Tier-1 methods in one study","pmids":[],"is_preprint":true},{"year":2025,"finding":"All-atom molecular dynamics simulations show that V2Rpp engages β-arr1 more stably than β-arr2, with isoform-specific residue contacts triggering distinct allosteric conformational changes including differential interdomain rotations; β-arr1 shows stronger allosteric coupling between V2Rpp and c-edge loop 2, consistent with enhanced membrane association of β-arr1.","method":"All-atom molecular dynamics simulations, machine learning, graph neural networks","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 4 / Weak — computational only, no experimental validation reported in abstract","pmids":[],"is_preprint":true},{"year":2016,"finding":"ARRB1 overexpression in NSCLC cells enhances activation of ATR and Chk1 kinases and increases γH2AX phosphorylation following treatment with DNA-damaging agents (cisplatin, etoposide), leading to increased DNA damage and apoptosis; ARRB1 knockdown abrogates this DNA damage response.","method":"ARRB1 plasmid overexpression and siRNA knockdown in NSCLC lines, Western blot for ATR/Chk1/γH2AX, apoptosis assay, mouse xenograft with cisplatin","journal":"Oncology reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — gain- and loss-of-function with defined signaling phenotype, in vivo xenograft validation, single lab","pmids":["28035404"],"is_preprint":false},{"year":2014,"finding":"ARRB1 is required for nicotine-induced upregulation of stem cell factor (SCF/c-Kit ligand) in NSCLC cells via E2F1; depletion of ARRB1 or E2F1 abrogates nicotine-promoted self-renewal of side-population (SP) stem-like cells, and E2F1 directly induces SCF transcription.","method":"Microarray, siRNA knockdown of ARRB1/E2F1, SP cell self-renewal assay, qRT-PCR","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — microarray plus siRNA with functional readout, single lab, no direct ChIP for ARRB1 at SCF promoter","pmids":["25401222"],"is_preprint":false},{"year":2025,"finding":"ARRB1-Δexon13 splice isoform (lacking exon 13) binds glycolytic proteins ENO1 and ALDOA and regulates glycolysis in glioblastoma cells more potently than the full-length ARRB1-OE isoform; inhibition of glycolysis with 2-DG suppresses the malignancy-promoting effects of ARRB1-Δexon13.","method":"Co-immunoprecipitation (ARRB1-Δexon13 with ENO1/ALDOA), OE and Δexon13 cell lines, in vivo xenograft, 2-DG glycolysis inhibition","journal":"Biochemistry and biophysics reports","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — Co-IP of isoform with glycolytic enzymes, in vivo xenograft, single lab","pmids":["40486495"],"is_preprint":false},{"year":2025,"finding":"Association of IGF1R with ARRB1 peaks at 60 min of Aβ treatment in neuronal cells, coinciding with maximal pERK activity; ARRB1 knockdown in IGF1R-overexpressing cells reduces cAMP, indicating that the IGF1R-ARRB1 interaction contributes to cAMP regulation under Aβ conditions; IGF1R inhibitor PPP blocks the IGF1R-ARRB1 interaction and alters ERK/cAMP status.","method":"Co-immunoprecipitation (time-course), siRNA knockdown, IGF1R overexpression, cAMP measurement, pERK assay, PPP inhibitor treatment","journal":"Molecular neurobiology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — Co-IP time-course, KD/OE with signaling readouts, single lab","pmids":["39969678"],"is_preprint":false}],"current_model":"ARRB1 (β-arrestin 1) is a multifunctional scaffold/adaptor protein that, beyond its canonical role in GPCR desensitization (binding phosphorylated active rhodopsin to quench G-protein signaling and facilitating receptor endocytosis), translocates to the nucleus to bind E2F transcription factors and regulate proliferative/survival gene expression, forms complexes with BECN1-PIK3C3 to promote autophagosome formation, interacts with GDF15 precursor to facilitate Golgi-directed maturation, blocks TRAF6-mediated K6-polyubiquitination of ASK1 to suppress stress kinase activation, facilitates NOTCH1 ubiquitination and degradation through a DTX1 complex, scaffolds PI3K-Akt signaling downstream of EP4, and undergoes P300-mediated lactylation (at K195) that upregulates S100A9 and promotes mitochondrial dysfunction; collectively these activities position ARRB1 as a context-dependent regulator of autophagy, metabolism, transcription, and cell survival across multiple tissues."},"narrative":{"mechanistic_narrative":"ARRB1 (β-arrestin 1) is a multifunctional adaptor/scaffold that, beyond its canonical role in quenching G-protein-coupled receptor signaling, acts as a context-dependent regulator of autophagy, transcription, metabolism, and cell survival across diverse tissues [PMID:24988431, PMID:21212384, PMID:24837709]. In its founding function it binds phosphorylated active receptors to terminate signaling: arrestin short isoforms bind both inactive and active phosphorylated rhodopsin/opsin and quench transducin activation on a subsecond timescale [PMID:12194979], and arrestin-mediated receptor deactivation operates in the same pathway as PP2A-dependent rhodopsin dephosphorylation to sustain photoreceptor viability [PMID:35861670]. Structural and biophysical work on the mGluR8–β-arrestin1 complex defines a steric desensitization mechanism in which β-arrestin1 stabilizes active receptor conformations through combined 'tail' and 'core' interactions. ARRB1 nucleates autophagosome formation by interacting with BECN1/Beclin 1 and PIK3C3/Vps34, promoting their assembly and PIK3C3 kinase activity under ischemic stress in neurons [PMID:24988431] and in nucleus pulposus cells [PMID:38838859]; in HBV-related hepatocellular carcinogenesis ARRB1 couples with HBx and LC3 to drive autophagic flux and CDK2–CCNE1-dependent G1/S transition [PMID:33866937]. ARRB1 also translocates to the nucleus, where it binds E2F transcription factors with EP300 to activate survival/proliferative genes (CDC6, TYMS, BIRC5) and SCF/c-Kit ligand downstream of nicotine [PMID:21212384, PMID:25401222], and maps genome-wide to regulate HIF1A targets SDHA and FH to drive aerobic glycolysis [PMID:24837709]. As a metabolic and signaling hub it tunes glycolytic versus oxidative flux via MPC1 and GLUT1 [PMID:33920080], scaffolds PI3K/Akt downstream of EP4 to protect mucosal integrity [PMID:28432343], facilitates Golgi-directed maturation of pro-GDF15 [PMID:31857195], and suppresses stress signaling by binding ASK1 to block TRAF6-mediated K6-polyubiquitination [PMID:32445435] and by binding p-eIF2α to inhibit the ATF4–CHOP ER stress axis [PMID:38252352]. ARRB1 promotes NOTCH1 ubiquitination and degradation through a DTX1 complex, functioning as a tumor suppressor in T-ALL [PMID:31822496]. Its activity is itself controlled by post-translational modification and transcriptional regulation: P300-mediated lactylation at K195 upregulates S100A9 and drives mitochondrial dysfunction after subarachnoid hemorrhage [PMID:40445496], and EHMT2-deposited H3K9me2 silences ARRB1 to derepress Hedgehog signaling [PMID:38573544].","teleology":[{"year":2002,"claim":"Established the kinetic and binding logic of arrestin-mediated receptor quenching by showing how short arrestin isoforms engage phosphorylated rhodopsin to terminate G-protein activation.","evidence":"In vitro reconstitution with size-exclusion chromatography, membrane-binding assays, and transducin quenching kinetics","pmids":["12194979"],"confidence":"High","gaps":["Does not address full-length ARRB1 behavior outside the visual system","No structural model of the active complex"]},{"year":2011,"claim":"Revealed an unexpected nuclear/transcriptional function for ARRB1, showing it partners with E2F and EP300 at survival-gene promoters to mediate mitogenic signaling.","evidence":"Nuclear fractionation, ChIP on cell lines and primary NSCLC tumors, reciprocal Co-IP, shRNA rescue","pmids":["21212384"],"confidence":"High","gaps":["Mechanism of nuclear import not defined","Direct DNA contact vs E2F-bridged recruitment unresolved"]},{"year":2014,"claim":"Connected ARRB1's nuclear role to metabolic reprogramming and extended its scaffolding to autophagy, defining it as a regulator of both transcription and the BECN1 autophagic core.","evidence":"Genome-wide ChIP-seq with expression profiling (HIF1A/SDHA/FH); reciprocal Co-IP, Arrb1-KO mice, and PIK3C3 kinase assay (BECN1-PIK3C3)","pmids":["24837709","24988431"],"confidence":"High","gaps":["Why interaction is ischemia-specific not explained","Direct vs indirect promoter occupancy in metabolic regulation unclear"]},{"year":2016,"claim":"Showed ARRB1 modulates the DNA damage response, linking its abundance to ATR/Chk1/γH2AX signaling and chemosensitivity.","evidence":"Gain- and loss-of-function in NSCLC lines, ATR/Chk1/γH2AX Western blot, xenograft with cisplatin","pmids":["28035404"],"confidence":"Medium","gaps":["No direct molecular interaction with DDR machinery identified","Mechanism of ATR/Chk1 enhancement unknown"]},{"year":2017,"claim":"Positioned ARRB1 as a scaffold for PI3K/Akt downstream of EP4, broadening its role to receptor-coupled cytoprotective signaling.","evidence":"Arrb1-KO mice in DSS colitis, siRNA in HCT116, PI3K/p-Akt Western blot, PGE2 treatment","pmids":["28432343"],"confidence":"Medium","gaps":["Direct PI3K binding not demonstrated","Single lab, no reciprocal validation"]},{"year":2019,"claim":"Defined two distinct trafficking/degradation functions: facilitating Golgi-directed pro-GDF15 maturation and promoting NOTCH1 ubiquitination via a DTX1 complex.","evidence":"Co-IP, Arrb1-KO mice with NASH models and rescue (GDF15); Co-IP of trimeric complex, ubiquitination assay, xenograft, 3'-UTR reporter (NOTCH1/DTX1)","pmids":["31857195","31822496"],"confidence":"High","gaps":["How ARRB1 selects pro-GDF15 vs other cargo unclear","Whether ARRB1 directly bridges NOTCH1 to DTX1 structurally not resolved"]},{"year":2020,"claim":"Showed ARRB1 suppresses stress kinase signaling by binding ASK1 and blocking TRAF6-mediated K6-linked polyubiquitination, establishing an epistatic effector.","evidence":"Co-IP, ubiquitination assay, Arrb1-KO and hepatocyte overexpression mice, ASK1 inhibitor rescue","pmids":["32445435"],"confidence":"High","gaps":["Structural basis of ubiquitination blockade unknown","Whether ARRB1 acts as competitor or allosteric inhibitor unclear"]},{"year":2021,"claim":"Extended ARRB1 autophagy function to HBV carcinogenesis (HBx/LC3 coupling to cell-cycle progression) and to metabolic reprogramming via MPC1/GLUT1.","evidence":"Co-IP of trimeric complex, genetic perturbations, CDK2 kinase assay, mouse HCC models (HBx); KO/re-expression, Seahorse, glucose uptake (bladder CSC)","pmids":["33866937","33920080"],"confidence":"Medium","gaps":["Direct mechanism linking autophagy to CDK2 activity not fully defined","How ARRB1 controls MPC1/GLUT1 protein levels unknown"]},{"year":2024,"claim":"Identified ER-stress suppression (p-eIF2α binding) and transcriptional control of ARRB1 itself (EHMT2-mediated H3K9me2 silencing repressing Hedgehog), plus ARRB1-driven NPAS2 activation in glycolysis.","evidence":"Co-IP, Arrb1-KO/OE rescue, ER-stress markers (eIF2α); ChIP for H3K9me2 at ARRB1 promoter and rescue (EHMT2); ChIP and rescue (NPAS2)","pmids":["38252352","38573544","38584327"],"confidence":"Medium","gaps":["Direct vs indirect eIF2α interaction in cells not fully validated","Whether ARRB1 binds NPAS2 promoter directly or via cofactors unclear"]},{"year":2025,"claim":"Resolved structural mechanism of GPCR coupling (mGluR8 cryo-EM) and uncovered new regulatory modes: K195 lactylation, GNAI1-ARRB1 disruption-driven autophagic death, calcium/CAMK2G-driven nuclear translocation, and an Δexon13 glycolytic isoform.","evidence":"Cryo-EM/smFRET/MD (mGluR8); lactylome and K195R mutant (lactylation); DARTS/CETSA/docking (PA/GNAI1); Co-IP and CA9 reporter (CAMK2G); Co-IP with ENO1/ALDOA (Δexon13)","pmids":["40445496","42088441","41339621","40486495"],"confidence":"Medium","gaps":["mGluR8 structure is a preprint awaiting peer review","Generality of K195 lactylation beyond SAH unknown","Functional distinction of Δexon13 isoform across tissues unmapped"]},{"year":null,"claim":"How a single adaptor integrates its many context-specific functions — receptor desensitization, nuclear transcription, autophagy scaffolding, ubiquitination control, and metabolic regulation — and what determines which program is engaged remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unifying model linking subcellular localization to functional choice","Determinants of partner selection (E2F vs BECN1 vs ASK1 vs DTX1) not defined","Role of post-translational modifications in switching functions largely uncharacterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1,4,5,6]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[6,17,19]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[1,2,14]},{"term_id":"GO:0042393","term_label":"histone binding","supporting_discovery_ids":[1]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[1,2,13]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,6]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[17,19]}],"pathway":[{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[0,5,16]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[1,2,14]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[9,17,19]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[2,8,23]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[4,6]}],"complexes":["BECN1-PIK3C3 autophagic core complex","ARRB1-NOTCH1-DTX1 complex"],"partners":["BECN1","PIK3C3","E2F1","NOTCH1","DTX1","ASK1","MAP1LC3","GNAI1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P49407","full_name":"Beta-arrestin-1","aliases":["Arrestin beta-1","Non-visual arrestin-2"],"length_aa":418,"mass_kda":47.1,"function":"Functions in regulating agonist-mediated G-protein coupled receptor (GPCR) signaling by mediating both receptor desensitization and resensitization processes (PubMed:37209686, PubMed:38175886). During homologous desensitization, beta-arrestins bind to the GPRK-phosphorylated receptor and sterically preclude its coupling to the cognate G-protein; the binding appears to require additional receptor determinants exposed only in the active receptor conformation. The beta-arrestins target many receptors for internalization by acting as endocytic adapters (CLASPs, clathrin-associated sorting proteins) and recruiting the GPRCs to the adapter protein 2 complex 2 (AP-2) in clathrin-coated pits (CCPs). However, the extent of beta-arrestin involvement appears to vary significantly depending on the receptor, agonist and cell type. Internalized arrestin-receptor complexes traffic to intracellular endosomes, where they remain uncoupled from G-proteins. Two different modes of arrestin-mediated internalization occur. Class A receptors, like ADRB2, OPRM1, ENDRA, D1AR and ADRA1B dissociate from beta-arrestin at or near the plasma membrane and undergo rapid recycling. Class B receptors, like AVPR2, AGTR1, NTSR1, TRHR and TACR1 internalize as a complex with arrestin and traffic with it to endosomal vesicles, presumably as desensitized receptors, for extended periods of time. Receptor resensitization then requires that receptor-bound arrestin is removed so that the receptor can be dephosphorylated and returned to the plasma membrane. Involved in internalization of P2RY4 and UTP-stimulated internalization of P2RY2. Involved in phosphorylation-dependent internalization of OPRD1 ands subsequent recycling. Involved in the degradation of cAMP by recruiting cAMP phosphodiesterases to ligand-activated receptors. Beta-arrestins function as multivalent adapter proteins that can switch the GPCR from a G-protein signaling mode that transmits short-lived signals from the plasma membrane via small molecule second messengers and ion channels to a beta-arrestin signaling mode that transmits a distinct set of signals that are initiated as the receptor internalizes and transits the intracellular compartment. Acts as a signaling scaffold for MAPK pathways such as MAPK1/3 (ERK1/2). ERK1/2 activated by the beta-arrestin scaffold is largely excluded from the nucleus and confined to cytoplasmic locations such as endocytic vesicles, also called beta-arrestin signalosomes. Recruits c-Src/SRC to ADRB2 resulting in ERK activation. GPCRs for which the beta-arrestin-mediated signaling relies on both ARRB1 and ARRB2 (codependent regulation) include ADRB2, F2RL1 and PTH1R. For some GPCRs the beta-arrestin-mediated signaling relies on either ARRB1 or ARRB2 and is inhibited by the other respective beta-arrestin form (reciprocal regulation). Inhibits ERK1/2 signaling in AGTR1- and AVPR2-mediated activation (reciprocal regulation). Is required for SP-stimulated endocytosis of NK1R and recruits c-Src/SRC to internalized NK1R resulting in ERK1/2 activation, which is required for the antiapoptotic effects of SP. Is involved in proteinase-activated F2RL1-mediated ERK activity. Acts as a signaling scaffold for the AKT1 pathway. Is involved in alpha-thrombin-stimulated AKT1 signaling. Is involved in IGF1-stimulated AKT1 signaling leading to increased protection from apoptosis. Involved in activation of the p38 MAPK signaling pathway and in actin bundle formation. Involved in F2RL1-mediated cytoskeletal rearrangement and chemotaxis. Involved in AGTR1-mediated stress fiber formation by acting together with GNAQ to activate RHOA. Appears to function as signaling scaffold involved in regulation of MIP-1-beta-stimulated CCR5-dependent chemotaxis. Involved in attenuation of NF-kappa-B-dependent transcription in response to GPCR or cytokine stimulation by interacting with and stabilizing CHUK. May serve as nuclear messenger for GPCRs. Involved in OPRD1-stimulated transcriptional regulation by translocating to CDKN1B and FOS promoter regions and recruiting EP300 resulting in acetylation of histone H4. Involved in regulation of LEF1 transcriptional activity via interaction with DVL1 and/or DVL2 Also involved in regulation of receptors other than GPCRs. Involved in Toll-like receptor and IL-1 receptor signaling through the interaction with TRAF6 which prevents TRAF6 autoubiquitination and oligomerization required for activation of NF-kappa-B and JUN. Binds phosphoinositides. Binds inositolhexakisphosphate (InsP6) (By similarity). Involved in IL8-mediated granule release in neutrophils. Required for atypical chemokine receptor ACKR2-induced RAC1-LIMK1-PAK1-dependent phosphorylation of cofilin (CFL1) and for the up-regulation of ACKR2 from endosomal compartment to cell membrane, increasing its efficiency in chemokine uptake and degradation. Involved in the internalization of the atypical chemokine receptor ACKR3. Negatively regulates the NOTCH signaling pathway by mediating the ubiquitination and degradation of NOTCH1 by ITCH (PubMed:23886940). Participates in the recruitment of the ubiquitin-protein ligase to the receptor (PubMed:23886940). Involved in some MRGPRE-mediated signaling required to improve glucose tolerance: promotes phosphorylation of ALDOA downstream of MRGPRE activation, increasing glycolysis and leading to GLP-1 secretion (PubMed:40446798)","subcellular_location":"Cytoplasm; Nucleus; Cell membrane; Membrane, clathrin-coated pit; Cell projection, pseudopodium; Cytoplasmic vesicle","url":"https://www.uniprot.org/uniprotkb/P49407/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ARRB1","classification":"Not Classified","n_dependent_lines":10,"n_total_lines":1208,"dependency_fraction":0.008278145695364239},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ARRB1","total_profiled":1310},"omim":[{"mim_id":"619768","title":"ARRESTIN DOMAIN-CONTAINING PROTEIN 1; ARRDC1","url":"https://www.omim.org/entry/619768"},{"mim_id":"613755","title":"MICRO RNA 326; MIR326","url":"https://www.omim.org/entry/613755"},{"mim_id":"613572","title":"G PROTEIN-COUPLED RECEPTOR, FAMILY C, GROUP 6, MEMBER A; GPRC6A","url":"https://www.omim.org/entry/613572"},{"mim_id":"612464","title":"ARRESTIN DOMAIN-CONTAINING PROTEIN 3; ARRDC3","url":"https://www.omim.org/entry/612464"},{"mim_id":"606409","title":"ITCHY E3 UBIQUITIN PROTEIN LIGASE; ITCH","url":"https://www.omim.org/entry/606409"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/ARRB1"},"hgnc":{"alias_symbol":[],"prev_symbol":["ARR1"]},"alphafold":{"accession":"P49407","domains":[{"cath_id":"2.60.40.840","chopping":"5-172","consensus_level":"high","plddt":87.2435,"start":5,"end":172},{"cath_id":"2.60.40.640","chopping":"182-351","consensus_level":"high","plddt":89.2951,"start":182,"end":351}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P49407","model_url":"https://alphafold.ebi.ac.uk/files/AF-P49407-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P49407-F1-predicted_aligned_error_v6.png","plddt_mean":82.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ARRB1","jax_strain_url":"https://www.jax.org/strain/search?query=ARRB1"},"sequence":{"accession":"P49407","fasta_url":"https://rest.uniprot.org/uniprotkb/P49407.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P49407/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P49407"}},"corpus_meta":[{"pmid":"11691951","id":"PMC_11691951","title":"ARR1, a transcription factor for genes immediately responsive to cytokinins.","date":"2001","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/11691951","citation_count":355,"is_preprint":false},{"pmid":"24988431","id":"PMC_24988431","title":"ARRB1/β-arrestin-1 mediates neuroprotection through coordination of BECN1-dependent autophagy in cerebral ischemia.","date":"2014","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/24988431","citation_count":121,"is_preprint":false},{"pmid":"17202182","id":"PMC_17202182","title":"ARR1 directly activates cytokinin response genes that encode proteins with diverse regulatory functions.","date":"2007","source":"Plant & cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/17202182","citation_count":111,"is_preprint":false},{"pmid":"21212384","id":"PMC_21212384","title":"ARRB1-mediated regulation of E2F target genes in nicotine-induced growth of lung tumors.","date":"2011","source":"Journal of the National Cancer Institute","url":"https://pubmed.ncbi.nlm.nih.gov/21212384","citation_count":93,"is_preprint":false},{"pmid":"25552473","id":"PMC_25552473","title":"Low temperature inhibits root growth by reducing auxin accumulation via ARR1/12.","date":"2014","source":"Plant & cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/25552473","citation_count":80,"is_preprint":false},{"pmid":"31004703","id":"PMC_31004703","title":"miR-374a-5p promotes tumor progression by targeting ARRB1 in triple negative breast cancer.","date":"2019","source":"Cancer letters","url":"https://pubmed.ncbi.nlm.nih.gov/31004703","citation_count":65,"is_preprint":false},{"pmid":"31857195","id":"PMC_31857195","title":"ARRB1 inhibits non-alcoholic steatohepatitis progression by promoting GDF15 maturation.","date":"2019","source":"Journal of hepatology","url":"https://pubmed.ncbi.nlm.nih.gov/31857195","citation_count":64,"is_preprint":false},{"pmid":"33866937","id":"PMC_33866937","title":"HBx induces hepatocellular carcinogenesis through ARRB1-mediated autophagy to drive the G1/S cycle.","date":"2021","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/33866937","citation_count":58,"is_preprint":false},{"pmid":"24837709","id":"PMC_24837709","title":"Nuclear ARRB1 induces pseudohypoxia and cellular metabolism reprogramming in prostate cancer.","date":"2014","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/24837709","citation_count":57,"is_preprint":false},{"pmid":"28432343","id":"PMC_28432343","title":"COX-1/PGE2/EP4 alleviates mucosal injury by upregulating β-arr1-mediated Akt signaling in colitis.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/28432343","citation_count":38,"is_preprint":false},{"pmid":"12194979","id":"PMC_12194979","title":"Arrestin and its splice variant Arr1-370A (p44). 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nuclear ARRB1 binds E2F transcription factors and, together with EP300 and acetylated histone H3, occupies promoters of E2F-regulated survival/proliferative genes (CDC6, TYMS, BIRC5), driving their transcriptional activation and mediating nicotine's mitogenic and antiapoptotic effects.\",\n      \"method\": \"Nuclear fractionation/immunofluorescence, shRNA knockdown, chromatin immunoprecipitation (ChIP), co-immunoprecipitation, qRT-PCR, human NSCLC tumors\",\n      \"journal\": \"Journal of the National Cancer Institute\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — nuclear localization by fractionation, ChIP on cell lines and primary tumors, reciprocal Co-IP, shRNA rescue; multiple orthogonal methods in one study\",\n      \"pmids\": [\"21212384\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Nuclear ARRB1 in prostate cancer cells regulates HIF1A transcriptional activity under normoxic conditions (pseudohypoxia) by controlling the expression of succinate dehydrogenase A (SDHA) and fumarate hydratase (FH), thereby shifting cellular metabolism toward aerobic glycolysis; this was established by genome-wide chromatin binding mapping (ChIP-seq) combined with gene expression profiling.\",\n      \"method\": \"Genome-wide ChIP-seq (first for an endocytic adaptor), gene expression profiling, in vitro and in vivo models\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genome-wide ChIP-seq with gene expression profiling, in vitro and in vivo validation; multiple orthogonal methods\",\n      \"pmids\": [\"24837709\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"ARRB1 interacts with GDF15 precursor (pro-GDF15) and facilitates its transportation to the Golgi apparatus for cleavage and maturation; loss of ARRB1 impairs this process, reduces mature GDF15, and accelerates NASH, while re-expression of ARRB1 together with pro-GDF15 overexpression is synergistically protective.\",\n      \"method\": \"Co-immunoprecipitation, Arrb1-KO mice, HFD/MCD NASH models, in vitro and in vivo rescue experiments\",\n      \"journal\": \"Journal of hepatology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Co-IP identifying interaction, KO mice with defined phenotype, in vivo and in vitro rescue; multiple orthogonal methods\",\n      \"pmids\": [\"31857195\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"ARRB1 promotes NOTCH1 ubiquitination and degradation in T-ALL cells through simultaneous interactions with NOTCH1 and the E3 ubiquitin ligase DTX1, acting as a tumor suppressor; this function is suppressed by oncomiR miR-223 which targets the 3'-UTR of ARRB1.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, exogenous ARRB1 expression, T-ALL xenograft models, luciferase 3'-UTR reporter\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Co-IP showing trimeric complex, ubiquitination assay, in vivo xenograft, 3'-UTR reporter; multiple orthogonal methods\",\n      \"pmids\": [\"31822496\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"ARRB1 interacts with HBx and the autophagic scaffold protein MAP1LC3/LC3, promoting autophagic flux and autophagosome formation; this ARRB1-mediated autophagy drives cell cycle progression by maintaining CDK2 phosphorylation and CDK2-CCNE1 complex activity, thereby promoting G1/S transition in HBV-related hepatocellular carcinogenesis.\",\n      \"method\": \"Co-immunoprecipitation, ARRB1 knockdown/knockout, autophagy inhibitor (3-MA), ATG5/ATG7 siRNA, cell cycle analysis, CDK2 kinase assay, mouse HCC models\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Co-IP of trimeric complex, multiple genetic perturbations, in vivo mouse models, kinase activity assay; multiple orthogonal methods\",\n      \"pmids\": [\"33866937\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ARRB1 directly interacts with ASK1 in hepatocytes and inhibits TRAF6-mediated Lysine 6-linked polyubiquitination of ASK1, preventing ASK1 activation and downstream signaling during hepatic ischemia/reperfusion injury; inhibition of ASK1 abolished the disruptive effect of ARRB1 deficiency, confirming ASK1 as a required effector of ARRB1 function.\",\n      \"method\": \"Co-immunoprecipitation, ARRB1 hepatocyte-specific overexpression, Arrb1-KO mice, ASK1 inhibitor rescue, ubiquitination assay\",\n      \"journal\": \"Journal of cellular and molecular medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Co-IP, ubiquitination assay, KO and overexpression mouse models with epistasis rescue; multiple orthogonal methods\",\n      \"pmids\": [\"32445435\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ARRB1 directly binds phosphorylated eIF2α (p-eIF2α) and eIF2α, as shown by co-immunoprecipitation, and this interaction inhibits ER stress signaling (p-eIF2α-ATF4-CHOP axis) and downstream apoptosis (cleaved caspase-3) in APAP-induced hepatotoxicity.\",\n      \"method\": \"Co-immunoprecipitation, ARRB1-KO mice, ARRB1 overexpression in hepatic cell lines and primary hepatocytes, Western blot for ER stress markers\",\n      \"journal\": \"Cell biology and toxicology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP identifying direct binding, KO mouse and OE rescue, single lab with two orthogonal methods\",\n      \"pmids\": [\"38252352\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"ARRB1 knockout in bladder cancer stem cell-like cells decreases glycolytic rate and induces metabolic reprogramming toward oxidative phosphorylation by increasing mitochondrial pyruvate carrier MPC1 protein levels and reducing GLUT1 protein levels and glucose uptake; ARRB1 overexpression in KO cells reverses this phenotype.\",\n      \"method\": \"ARRB1 KO and re-expression, Seahorse metabolic flux assay, glucose uptake assay, Western blot for MPC1 and GLUT1, spheroid formation\",\n      \"journal\": \"Cancers\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO with defined metabolic phenotype plus rescue experiment and multiple metabolic readouts, single lab\",\n      \"pmids\": [\"33920080\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"EP4 receptor activation by PGE2 upregulates β-arrestin1 (ARRB1), which in turn scaffolds PI3K/Akt signaling to protect colonic mucosal integrity; ARRB1-deficient mice show markedly downregulated PI3K and p-Akt expression during DSS-induced colitis.\",\n      \"method\": \"Arrb1-KO mice, DSS colitis model, siRNA knockdown in HCT116 cells, Western blot for PI3K/p-Akt, PGE2 treatment\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO mouse with defined signaling phenotype and in vitro siRNA validation, single lab\",\n      \"pmids\": [\"28432343\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"ET-1 activates ETA/ETB receptors to trigger mesothelial-to-mesenchymal transition (MMT) via β-arrestin1-dependent MAPK and NF-kB pathways; silencing of β-arrestin1 impairs ET-1-induced MC proliferation, upregulation of mesenchymal markers (fibronectin, α-SMA, N-cadherin, vimentin), NF-kB-dependent Snail activity, and SOC transmesothelial migration.\",\n      \"method\": \"β-arrestin1 siRNA silencing, ETA/ETB receptor blockade, Western blot, migration/invasion assays\",\n      \"journal\": \"Frontiers in cell and developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — silencing with defined signaling phenotype, receptor blockade epistasis, single lab, no reconstitution\",\n      \"pmids\": [\"34926453\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"P300 mediates lactylation of ARRB1 at lysine 195 following subarachnoid hemorrhage, increasing ARRB1 protein expression and upregulating S100A9, which promotes mitochondrial dysfunction and neuronal apoptosis; a K195R mutation abolishes this effect, and P300 knockdown is rescued by ARRB1 overexpression.\",\n      \"method\": \"Lactylome analysis, co-immunoprecipitation, K195R point mutant, P300 knockdown/overexpression rescue, co-immunofluorescence, mitochondrial function assays (MMP, ROS, ATP, OCR), TUNEL/flow cytometry\",\n      \"journal\": \"Neurochemical research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — site-specific mutant abolishes effect, writer identified (P300), multiple functional readouts, single lab\",\n      \"pmids\": [\"40445496\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ARRB1 is identified as an essential adaptor for patchouli alcohol (PA)-induced autophagic cell death in NSCLC; PA specifically disrupts the GNAI1-ARRB1 protein-protein interaction (confirmed by DARTS, CETSA, molecular docking), and loss of ARRB1 abolishes downstream inhibition of ERK/JAK2-STAT3/mTOR pro-survival pathways.\",\n      \"method\": \"DARTS, CETSA, molecular docking, Co-IP, ARRB1 knockdown, autophagy flux assays, in vivo xenograft\",\n      \"journal\": \"International journal of biological sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple target-engagement methods (DARTS, CETSA) plus functional KD, single lab\",\n      \"pmids\": [\"42088441\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ARRB1 nuclear translocation in lung epithelial cells is induced by simulated space radiation and/or microgravity via changes in intracellular calcium concentration, which promotes CAMK2G-ARRB1 interaction; nuclear ARRB1 then enhances CA9 transcriptional activity to facilitate malignant transformation.\",\n      \"method\": \"Co-immunoprecipitation (CAMK2G-ARRB1), nuclear fractionation/imaging, calcium manipulation, CA9 transcriptional reporter, malignant transformation assays\",\n      \"journal\": \"NPJ microgravity\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP identifies interaction, nuclear localization directly measured, transcriptional reporter, single lab\",\n      \"pmids\": [\"41339621\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ARRB1 transcriptionally activates NPAS2 by binding to sites within the NPAS2 promoter region; this ARRB1-NPAS2 axis promotes malignant behaviors and glycolysis in lung adenocarcinoma cells, as NPAS2 knockdown effects are partially restored by ARRB1 overexpression.\",\n      \"method\": \"ChIP, promoter-binding assay, gain/loss-of-function, Seahorse OCR, glycolytic enzyme expression, rescue experiments\",\n      \"journal\": \"Clinical and experimental pharmacology & physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP confirms promoter binding, epistasis rescue experiment, single lab\",\n      \"pmids\": [\"38584327\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"EHMT2 epigenetically suppresses ARRB1 transcription by binding the ARRB1 promoter and depositing H3K9me2 modification; reduced ARRB1 in turn fails to inhibit the Hedgehog pathway (GLI1, PTCH1), promoting OSCC cancer stem cell properties; ARRB1 overexpression counteracts EHMT2-driven Hedgehog activation.\",\n      \"method\": \"ChIP, lentiviral EHMT2 silencing, ARRB1 overexpression rescue, sphere formation assays, Western blot for H3K9me2/GLI1/PTCH1\",\n      \"journal\": \"Molecular biotechnology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP identifies H3K9me2 at ARRB1 promoter, rescue experiment, single lab\",\n      \"pmids\": [\"38573544\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ARRB1 interacts with Beclin 1 (BECN1) in nucleus pulposus cells, and ARRB1 knockdown suppresses formation of the Beclin1-PIK3C3 core complex, impairing autophagic flux; ARRB1 overexpression promotes autophagy, reduces extracellular matrix degradation and apoptosis, and delays IVDD progression in rats.\",\n      \"method\": \"Co-immunoprecipitation (ARRB1-Beclin1), lentiviral shRNA/OE, LC3-II/I ratio, autophagic flux assay, 3-MA autophagy inhibitor, in vivo rat IVDD model\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP, autophagy flux assay, in vivo model; single lab, replicates prior BECN1 interaction data\",\n      \"pmids\": [\"38838859\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"The arrestin splice variant p44 (Arr1-370A) and truncated Arr(3-367) bind not only phosphorylated active rhodopsin but also inactive phosphorylated rhodopsin and opsin, making them membrane-bound in the dark (unlike full-length arrestin); upon photoexcitation these short arrestins are handed over from inactive to active phosphorylated rhodopsin and quench Gt activation on a subsecond timescale.\",\n      \"method\": \"Size exclusion chromatography, biophysical membrane-binding assay, G-protein activation (Gt) quenching assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with biophysical assays, mechanistic detail on binding selectivity and kinetics; multiple orthogonal methods in single rigorous study\",\n      \"pmids\": [\"12194979\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"In rod photoreceptors lacking Arr1 (arrestin), PP2A deficiency accelerates retinal degeneration and further reduces maximal rod photoresponse amplitude; this genetic epistasis demonstrates that PP2A-mediated rhodopsin dephosphorylation acts in the same pathway as Arr1-mediated receptor deactivation, and that both are required for rod photoreceptor viability.\",\n      \"method\": \"Genetic double-knockout (Arr1-/- × PP2A Cα rod-specific KO), retinal histology, ex vivo electroretinography\",\n      \"journal\": \"Investigative ophthalmology & visual science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic epistasis with ERG functional readout, single lab\",\n      \"pmids\": [\"35861670\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Cryo-EM structures of mGluR8 complexed with β-arrestin1 reveal transducer-specific active states of mGluR8; single-molecule FRET shows β-arr1 stabilizes active mGluR8 conformations; mGluRs couple to β-arr1 with 2:1 or 2:2 stoichiometry via combined 'tail' and 'core' interactions; molecular dynamics supports a steric desensitization mechanism involving interactions with both subunits and the lipid bilayer.\",\n      \"method\": \"Cryo-EM structure determination, single-molecule pulldown assay, single-molecule FRET, molecular dynamics simulations, combinatorial mutagenesis\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structure plus smFRET plus MD simulations plus mutagenesis; multiple Tier-1 methods in one study\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"All-atom molecular dynamics simulations show that V2Rpp engages β-arr1 more stably than β-arr2, with isoform-specific residue contacts triggering distinct allosteric conformational changes including differential interdomain rotations; β-arr1 shows stronger allosteric coupling between V2Rpp and c-edge loop 2, consistent with enhanced membrane association of β-arr1.\",\n      \"method\": \"All-atom molecular dynamics simulations, machine learning, graph neural networks\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — computational only, no experimental validation reported in abstract\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"ARRB1 overexpression in NSCLC cells enhances activation of ATR and Chk1 kinases and increases γH2AX phosphorylation following treatment with DNA-damaging agents (cisplatin, etoposide), leading to increased DNA damage and apoptosis; ARRB1 knockdown abrogates this DNA damage response.\",\n      \"method\": \"ARRB1 plasmid overexpression and siRNA knockdown in NSCLC lines, Western blot for ATR/Chk1/γH2AX, apoptosis assay, mouse xenograft with cisplatin\",\n      \"journal\": \"Oncology reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — gain- and loss-of-function with defined signaling phenotype, in vivo xenograft validation, single lab\",\n      \"pmids\": [\"28035404\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"ARRB1 is required for nicotine-induced upregulation of stem cell factor (SCF/c-Kit ligand) in NSCLC cells via E2F1; depletion of ARRB1 or E2F1 abrogates nicotine-promoted self-renewal of side-population (SP) stem-like cells, and E2F1 directly induces SCF transcription.\",\n      \"method\": \"Microarray, siRNA knockdown of ARRB1/E2F1, SP cell self-renewal assay, qRT-PCR\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — microarray plus siRNA with functional readout, single lab, no direct ChIP for ARRB1 at SCF promoter\",\n      \"pmids\": [\"25401222\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ARRB1-Δexon13 splice isoform (lacking exon 13) binds glycolytic proteins ENO1 and ALDOA and regulates glycolysis in glioblastoma cells more potently than the full-length ARRB1-OE isoform; inhibition of glycolysis with 2-DG suppresses the malignancy-promoting effects of ARRB1-Δexon13.\",\n      \"method\": \"Co-immunoprecipitation (ARRB1-Δexon13 with ENO1/ALDOA), OE and Δexon13 cell lines, in vivo xenograft, 2-DG glycolysis inhibition\",\n      \"journal\": \"Biochemistry and biophysics reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — Co-IP of isoform with glycolytic enzymes, in vivo xenograft, single lab\",\n      \"pmids\": [\"40486495\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Association of IGF1R with ARRB1 peaks at 60 min of Aβ treatment in neuronal cells, coinciding with maximal pERK activity; ARRB1 knockdown in IGF1R-overexpressing cells reduces cAMP, indicating that the IGF1R-ARRB1 interaction contributes to cAMP regulation under Aβ conditions; IGF1R inhibitor PPP blocks the IGF1R-ARRB1 interaction and alters ERK/cAMP status.\",\n      \"method\": \"Co-immunoprecipitation (time-course), siRNA knockdown, IGF1R overexpression, cAMP measurement, pERK assay, PPP inhibitor treatment\",\n      \"journal\": \"Molecular neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — Co-IP time-course, KD/OE with signaling readouts, single lab\",\n      \"pmids\": [\"39969678\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ARRB1 (β-arrestin 1) is a multifunctional scaffold/adaptor protein that, beyond its canonical role in GPCR desensitization (binding phosphorylated active rhodopsin to quench G-protein signaling and facilitating receptor endocytosis), translocates to the nucleus to bind E2F transcription factors and regulate proliferative/survival gene expression, forms complexes with BECN1-PIK3C3 to promote autophagosome formation, interacts with GDF15 precursor to facilitate Golgi-directed maturation, blocks TRAF6-mediated K6-polyubiquitination of ASK1 to suppress stress kinase activation, facilitates NOTCH1 ubiquitination and degradation through a DTX1 complex, scaffolds PI3K-Akt signaling downstream of EP4, and undergoes P300-mediated lactylation (at K195) that upregulates S100A9 and promotes mitochondrial dysfunction; collectively these activities position ARRB1 as a context-dependent regulator of autophagy, metabolism, transcription, and cell survival across multiple tissues.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"ARRB1 (β-arrestin 1) is a multifunctional adaptor/scaffold that, beyond its canonical role in quenching G-protein-coupled receptor signaling, acts as a context-dependent regulator of autophagy, transcription, metabolism, and cell survival across diverse tissues [#0, #1, #2]. In its founding function it binds phosphorylated active receptors to terminate signaling: arrestin short isoforms bind both inactive and active phosphorylated rhodopsin/opsin and quench transducin activation on a subsecond timescale [#17], and arrestin-mediated receptor deactivation operates in the same pathway as PP2A-dependent rhodopsin dephosphorylation to sustain photoreceptor viability [#18]. Structural and biophysical work on the mGluR8–β-arrestin1 complex defines a steric desensitization mechanism in which β-arrestin1 stabilizes active receptor conformations through combined 'tail' and 'core' interactions [#19]. ARRB1 nucleates autophagosome formation by interacting with BECN1/Beclin 1 and PIK3C3/Vps34, promoting their assembly and PIK3C3 kinase activity under ischemic stress in neurons [#0] and in nucleus pulposus cells [#16]; in HBV-related hepatocellular carcinogenesis ARRB1 couples with HBx and LC3 to drive autophagic flux and CDK2–CCNE1-dependent G1/S transition [#5]. ARRB1 also translocates to the nucleus, where it binds E2F transcription factors with EP300 to activate survival/proliferative genes (CDC6, TYMS, BIRC5) and SCF/c-Kit ligand downstream of nicotine [#1, #22], and maps genome-wide to regulate HIF1A targets SDHA and FH to drive aerobic glycolysis [#2]. As a metabolic and signaling hub it tunes glycolytic versus oxidative flux via MPC1 and GLUT1 [#8], scaffolds PI3K/Akt downstream of EP4 to protect mucosal integrity [#9], facilitates Golgi-directed maturation of pro-GDF15 [#3], and suppresses stress signaling by binding ASK1 to block TRAF6-mediated K6-polyubiquitination [#6] and by binding p-eIF2α to inhibit the ATF4–CHOP ER stress axis [#7]. ARRB1 promotes NOTCH1 ubiquitination and degradation through a DTX1 complex, functioning as a tumor suppressor in T-ALL [#4]. Its activity is itself controlled by post-translational modification and transcriptional regulation: P300-mediated lactylation at K195 upregulates S100A9 and drives mitochondrial dysfunction after subarachnoid hemorrhage [#11], and EHMT2-deposited H3K9me2 silences ARRB1 to derepress Hedgehog signaling [#15].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Established the kinetic and binding logic of arrestin-mediated receptor quenching by showing how short arrestin isoforms engage phosphorylated rhodopsin to terminate G-protein activation.\",\n      \"evidence\": \"In vitro reconstitution with size-exclusion chromatography, membrane-binding assays, and transducin quenching kinetics\",\n      \"pmids\": [\"12194979\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not address full-length ARRB1 behavior outside the visual system\", \"No structural model of the active complex\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Revealed an unexpected nuclear/transcriptional function for ARRB1, showing it partners with E2F and EP300 at survival-gene promoters to mediate mitogenic signaling.\",\n      \"evidence\": \"Nuclear fractionation, ChIP on cell lines and primary NSCLC tumors, reciprocal Co-IP, shRNA rescue\",\n      \"pmids\": [\"21212384\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of nuclear import not defined\", \"Direct DNA contact vs E2F-bridged recruitment unresolved\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Connected ARRB1's nuclear role to metabolic reprogramming and extended its scaffolding to autophagy, defining it as a regulator of both transcription and the BECN1 autophagic core.\",\n      \"evidence\": \"Genome-wide ChIP-seq with expression profiling (HIF1A/SDHA/FH); reciprocal Co-IP, Arrb1-KO mice, and PIK3C3 kinase assay (BECN1-PIK3C3)\",\n      \"pmids\": [\"24837709\", \"24988431\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Why interaction is ischemia-specific not explained\", \"Direct vs indirect promoter occupancy in metabolic regulation unclear\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Showed ARRB1 modulates the DNA damage response, linking its abundance to ATR/Chk1/γH2AX signaling and chemosensitivity.\",\n      \"evidence\": \"Gain- and loss-of-function in NSCLC lines, ATR/Chk1/γH2AX Western blot, xenograft with cisplatin\",\n      \"pmids\": [\"28035404\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct molecular interaction with DDR machinery identified\", \"Mechanism of ATR/Chk1 enhancement unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Positioned ARRB1 as a scaffold for PI3K/Akt downstream of EP4, broadening its role to receptor-coupled cytoprotective signaling.\",\n      \"evidence\": \"Arrb1-KO mice in DSS colitis, siRNA in HCT116, PI3K/p-Akt Western blot, PGE2 treatment\",\n      \"pmids\": [\"28432343\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct PI3K binding not demonstrated\", \"Single lab, no reciprocal validation\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Defined two distinct trafficking/degradation functions: facilitating Golgi-directed pro-GDF15 maturation and promoting NOTCH1 ubiquitination via a DTX1 complex.\",\n      \"evidence\": \"Co-IP, Arrb1-KO mice with NASH models and rescue (GDF15); Co-IP of trimeric complex, ubiquitination assay, xenograft, 3'-UTR reporter (NOTCH1/DTX1)\",\n      \"pmids\": [\"31857195\", \"31822496\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How ARRB1 selects pro-GDF15 vs other cargo unclear\", \"Whether ARRB1 directly bridges NOTCH1 to DTX1 structurally not resolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Showed ARRB1 suppresses stress kinase signaling by binding ASK1 and blocking TRAF6-mediated K6-linked polyubiquitination, establishing an epistatic effector.\",\n      \"evidence\": \"Co-IP, ubiquitination assay, Arrb1-KO and hepatocyte overexpression mice, ASK1 inhibitor rescue\",\n      \"pmids\": [\"32445435\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of ubiquitination blockade unknown\", \"Whether ARRB1 acts as competitor or allosteric inhibitor unclear\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Extended ARRB1 autophagy function to HBV carcinogenesis (HBx/LC3 coupling to cell-cycle progression) and to metabolic reprogramming via MPC1/GLUT1.\",\n      \"evidence\": \"Co-IP of trimeric complex, genetic perturbations, CDK2 kinase assay, mouse HCC models (HBx); KO/re-expression, Seahorse, glucose uptake (bladder CSC)\",\n      \"pmids\": [\"33866937\", \"33920080\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct mechanism linking autophagy to CDK2 activity not fully defined\", \"How ARRB1 controls MPC1/GLUT1 protein levels unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified ER-stress suppression (p-eIF2α binding) and transcriptional control of ARRB1 itself (EHMT2-mediated H3K9me2 silencing repressing Hedgehog), plus ARRB1-driven NPAS2 activation in glycolysis.\",\n      \"evidence\": \"Co-IP, Arrb1-KO/OE rescue, ER-stress markers (eIF2α); ChIP for H3K9me2 at ARRB1 promoter and rescue (EHMT2); ChIP and rescue (NPAS2)\",\n      \"pmids\": [\"38252352\", \"38573544\", \"38584327\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct vs indirect eIF2α interaction in cells not fully validated\", \"Whether ARRB1 binds NPAS2 promoter directly or via cofactors unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved structural mechanism of GPCR coupling (mGluR8 cryo-EM) and uncovered new regulatory modes: K195 lactylation, GNAI1-ARRB1 disruption-driven autophagic death, calcium/CAMK2G-driven nuclear translocation, and an Δexon13 glycolytic isoform.\",\n      \"evidence\": \"Cryo-EM/smFRET/MD (mGluR8); lactylome and K195R mutant (lactylation); DARTS/CETSA/docking (PA/GNAI1); Co-IP and CA9 reporter (CAMK2G); Co-IP with ENO1/ALDOA (Δexon13)\",\n      \"pmids\": [\"40445496\", \"42088441\", \"41339621\", \"40486495\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"mGluR8 structure is a preprint awaiting peer review\", \"Generality of K195 lactylation beyond SAH unknown\", \"Functional distinction of Δexon13 isoform across tissues unmapped\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single adaptor integrates its many context-specific functions — receptor desensitization, nuclear transcription, autophagy scaffolding, ubiquitination control, and metabolic regulation — and what determines which program is engaged remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unifying model linking subcellular localization to functional choice\", \"Determinants of partner selection (E2F vs BECN1 vs ASK1 vs DTX1) not defined\", \"Role of post-translational modifications in switching functions largely uncharacterized\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1, 4, 5, 6]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [6, 17, 19]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [1, 2, 14]},\n      {\"term_id\": \"GO:0042393\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [1, 2, 13]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 6]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [17, 19]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [0, 5, 16]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [1, 2, 14]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [9, 17, 19]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [2, 8, 23]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [4, 6]}\n    ],\n    \"complexes\": [\"BECN1-PIK3C3 autophagic core complex\", \"ARRB1-NOTCH1-DTX1 complex\"],\n    \"partners\": [\"BECN1\", \"PIK3C3\", \"E2F1\", \"NOTCH1\", \"DTX1\", \"ASK1\", \"MAP1LC3\", \"GNAI1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}