{"gene":"PLIN1","run_date":"2026-04-28T19:45:44","timeline":{"discoveries":[{"year":2013,"finding":"FSP27 (CIDEC) interacts with PLIN1 in human primary adipocytes; the C-terminal domain of FSP27 (aa 120-220) binds PLIN1. Co-expression of both proteins increases average lipid droplet size and promotes unilocular adipocyte formation without additively reducing lipolysis beyond individual effects.","method":"Co-immunoprecipitation, co-localization by fluorescence microscopy, domain mapping (truncation constructs), triglyceride content and glycerol release assays in human primary adipocytes","journal":"Biochemical and biophysical research communications","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP with domain mapping, functional lipolysis readout, replicated in human primary adipocytes","pmids":["23399566"],"is_preprint":false},{"year":2013,"finding":"In adipocytes, PLIN1 regulates lipolysis by sequestering CGI-58 (ABHD5), an activator of ATGL; upon PKA-mediated phosphorylation of PLIN1, CGI-58 is released to fully activate ATGL and initiate triglyceride hydrolysis.","method":"Co-immunoprecipitation of PLIN1 with CGI-58 and ATGL in rat soleus (referenced as established adipocyte mechanism) and contrasted with skeletal muscle PLIN proteins","journal":"American journal of physiology. Regulatory, integrative and comparative physiology","confidence":"Medium","confidence_rationale":"Tier 3 — mechanism described via co-IP context in muscle study; foundational adipocyte mechanism supported across multiple studies","pmids":["23408028"],"is_preprint":false},{"year":2014,"finding":"A heterozygous frameshift mutation at the carboxy-terminus of PLIN1 (439fs) produces a mutant protein that binds and stabilizes ABHD5 (CGI-58) expression but fails to inhibit basal lipolysis as effectively as wild-type PLIN1, and is associated with smaller lipid droplets in stably transfected preadipocytes, demonstrating that the C-terminal domain of PLIN1 is required for full suppression of basal lipolysis.","method":"Stable transfection of preadipocytes with frameshift mutant vs. WT PLIN1, lipolysis assay (glycerol release), ABHD5 binding/expression analysis, lipid droplet size measurement","journal":"Diabetes","confidence":"High","confidence_rationale":"Tier 2 — loss-of-function mutant with specific cellular phenotype plus binding assay, multiple orthogonal readouts","pmids":["25114292"],"is_preprint":false},{"year":1998,"finding":"Human PLIN1 encodes a 522-amino-acid protein with 79% identity to rat perilipin; Northern blot showed adipose-tissue-specific expression among 20 adult human tissues; chromosomal location mapped to 15q26.","method":"Differential display cloning, Northern blot, fluorescence in situ hybridization (FISH)","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 — direct molecular cloning and expression mapping; localization without functional manipulation","pmids":["9521880"],"is_preprint":false},{"year":2017,"finding":"The PLIN1 gene promoter is subject to DNA methylation in human adipocytes; CpG methylation of the PLIN1 promoter is inversely correlated with PLIN1 mRNA expression and basal lipolysis in obese women. Methylated PLIN1 promoter reporter constructs show decreased activity in hMSC-derived adipocytes, and treatment with a DNA methyltransferase inhibitor increases PLIN1 mRNA and protein levels.","method":"CpG methylation array, reporter gene (luciferase) assay with methylated vs. unmethylated PLIN1 promoter construct, DNMT inhibitor treatment, correlation analysis with glycerol-release lipolysis assay","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 1-2 — functional reporter assay plus pharmacological intervention plus correlative methylation data, multiple orthogonal methods","pmids":["28860604"],"is_preprint":false},{"year":2019,"finding":"In C. elegans, the PLIN1 ortholog MDT-28/PLIN-1 mediates interaction between lipid droplets and microtubules via direct binding to the dynein light chain DLC-1; yeast two-hybrid and pull-down assays mapped the DLC-1-binding regions to amino acids 1-210 and 275-415 of MDT-28/PLIN-1. Fluorescence imaging confirmed that MDT-28/PLIN-1 mediates LD-microtubule contact, regulating LD distribution.","method":"Forward genetic screen, yeast two-hybrid, pull-down assay, fluorescence imaging in C. elegans","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 — yeast two-hybrid plus pull-down with domain mapping, functional imaging; C. elegans ortholog, context consistent with mammalian PLIN1","pmids":["31624276"],"is_preprint":false},{"year":2020,"finding":"PLIN1 knockout in 3T3-L1 adipocytes (via CRISPR/Cas9) enhances basal lipolysis, as shown by increased glycerol release and decreased triglyceride content, accompanied by upregulation of HSL and ATGL mRNA and protein. Lipid droplet morphology shifts from unilocular to smaller, multiple droplets. PPARγ and FSP27 expression was unchanged.","method":"CRISPR/Cas9 knockout in 3T3-L1 adipocytes, glycerol/TG enzymatic assay, Oil Red O staining, Western blot, RT-PCR","journal":"Sheng wu gong cheng xue bao = Chinese journal of biotechnology","confidence":"Medium","confidence_rationale":"Tier 2 — clean KO with specific phenotypic readout (lipolysis) and multiple molecular markers","pmids":["32748596"],"is_preprint":false},{"year":2020,"finding":"In bovine adipocytes, the PLIN1 core promoter region (-209/-17 bp) is activated by transcription factors E2F1, PLAG1, and C/EBPβ, and repressed by SMAD3, as demonstrated by promoter deletion assays, luciferase reporter assays with mutated binding sites, siRNA knockdown, and EMSA.","method":"Promoter deletion constructs, luciferase reporter assay, site-directed mutagenesis, siRNA knockdown, EMSA","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal methods (reporter assay, mutagenesis, EMSA, siRNA) in bovine adipocytes","pmids":["31981700"],"is_preprint":false},{"year":2022,"finding":"PLIN1 overexpression in M1 macrophages increases lipid droplet size and reduces expression of TNFA, MMP2, ABCA1, and ABCG1; PLIN1 silencing in M2 macrophages has opposite effects on LD size and gene expression, establishing PLIN1 as a regulator of macrophage inflammatory polarity through lipid storage modulation.","method":"PLIN1 overexpression and siRNA silencing in cultured human macrophages, immunohistochemistry of carotid endarterectomy plaques, quantitative RT-PCR","journal":"Journal of atherosclerosis and thrombosis","confidence":"Medium","confidence_rationale":"Tier 2-3 — gain- and loss-of-function with specific molecular readouts; single lab","pmids":["35662076"],"is_preprint":false},{"year":2024,"finding":"Hypertriglyceridemia in PLIN1-related familial partial lipodystrophy results from markedly decreased catabolism of VLDL and IDL (reduced indirect fractional catabolic rates of VLDL-apoB100 and IDL-apoB100), not from increased VLDL production. Plasma LPL mass was significantly lower in patients with PLIN1-mutated FPL than controls, despite similar LPL protein expression in adipose tissue, indicating impaired LPL availability due to reduced adipose mass.","method":"In vivo lipoprotein kinetic study (stable isotope tracer), plasma LPL mass measurement, LPL mRNA and protein expression in adipose tissue biopsy","journal":"Arteriosclerosis, thrombosis, and vascular biology","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo kinetic study with mechanistic quantification, n=6 patients vs. controls","pmids":["38899472"],"is_preprint":false},{"year":2025,"finding":"The C-terminal domain of mouse PLIN1 (mPLIN1C) behaves as an intrinsically disordered region (IDR) with coil-like or pre-molten globule character; circular dichroism spectroscopy shows predominance of disordered secondary structure. Interaction with SDS micelles induces a conformational transition, and the EPESE sequence (residues 413-417) was identified as a potential molecular recognition feature (MoRF) for partner-molecule binding (including CGI-58).","method":"Circular dichroism spectroscopy, bioinformatic disorder prediction, SDS micelle interaction assay","journal":"Biochemistry and biophysics reports","confidence":"Medium","confidence_rationale":"Tier 1 — biophysical characterization with CD spectroscopy and micelle interaction; single study, no mutagenesis validation","pmids":["40109298"],"is_preprint":false},{"year":2025,"finding":"Seipin (BSCL2) is required for recruiting PLIN1 to the lipid droplet surface in human adipocytes; without seipin, lipid droplet biogenesis still occurs but PLIN1 fails to localize to droplets, resulting in enhanced lipolysis, ceramide accumulation, and adipocyte de-differentiation into a progenitor-like state. This identifies seipin as an upstream regulator of PLIN1 LD recruitment that enforces adipocyte identity.","method":"BSCL2 knockout in human adipocyte progenitor cells, live-cell imaging of PLIN1 localization, lipolysis assay, lipid/ceramide quantification, in vivo xenograft differentiation","journal":"bioRxiv","confidence":"High","confidence_rationale":"Tier 2 — clean KO with direct localization imaging, multiple functional readouts (lipolysis, ceramide, de-differentiation), in vivo validation","pmids":[],"is_preprint":true},{"year":2024,"finding":"During differentiation of 3T3 pre-adipocytes into adipocytes, PLIN1—a high-affinity LD protein—becomes predominantly recruited to lipid droplets and displaces other ER proteins through steric exclusion, demonstrating lateral protein-protein exclusion as a mechanism shaping the LD proteome.","method":"Ex vivo quantitative LD partitioning assay, fluorescence imaging during 3T3-L1 adipocyte differentiation, competition assay between LD-targeting proteins","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 — novel ex vivo assay with functional imaging; preprint, not yet peer-reviewed","pmids":[],"is_preprint":true}],"current_model":"PLIN1 (perilipin-1) is an adipocyte lipid droplet coat protein that suppresses basal lipolysis by sequestering the ATGL co-activator CGI-58/ABHD5 at the droplet surface; upon PKA-mediated phosphorylation, PLIN1 releases CGI-58 to activate ATGL-driven triglyceride hydrolysis. PLIN1 recruitment to the droplet surface is seipin-dependent, its C-terminal domain (which is intrinsically disordered) mediates CGI-58 binding and lipolysis control, it interacts with FSP27/CIDEC to regulate droplet size, it controls droplet-microtubule interaction via dynein light chain (in C. elegans), and its transcription is regulated by E2F1, PLAG1, C/EBPβ, SMAD3, and by promoter DNA methylation."},"narrative":{"teleology":[{"year":1998,"claim":"Cloning of human PLIN1 established it as a highly conserved, adipose-tissue-specific gene, providing the molecular foundation for studying its lipid droplet functions.","evidence":"Differential display cloning, Northern blot across 20 human tissues, and FISH mapping to 15q26","pmids":["9521880"],"confidence":"Medium","gaps":["No functional data on lipolysis or lipid droplet association at this stage","Protein localization to lipid droplets not directly demonstrated"]},{"year":2013,"claim":"The mechanism by which PLIN1 suppresses basal lipolysis was defined: PLIN1 sequesters the ATGL co-activator CGI-58 on the droplet surface, and PKA phosphorylation of PLIN1 releases CGI-58 to activate ATGL, establishing the canonical lipolysis-gating model.","evidence":"Co-immunoprecipitation of PLIN1 with CGI-58 and ATGL in adipocyte and muscle contexts","pmids":["23408028"],"confidence":"Medium","gaps":["Structural basis of CGI-58–PLIN1 interaction unknown","Precise phosphorylation sites mediating release not mapped in this study"]},{"year":2013,"claim":"PLIN1 was shown to physically interact with FSP27/CIDEC and cooperate in promoting unilocular lipid droplet formation in adipocytes, revealing a second effector partnership beyond CGI-58.","evidence":"Co-immunoprecipitation with domain mapping (FSP27 aa 120–220 binds PLIN1), lipid droplet size and lipolysis assays in human primary adipocytes","pmids":["23399566"],"confidence":"High","gaps":["PLIN1 domain mediating FSP27 binding not mapped","Mechanism by which the PLIN1–FSP27 complex enlarges droplets is unclear"]},{"year":2014,"claim":"A C-terminal frameshift mutation (439fs) demonstrated that the C-terminal domain of PLIN1 is essential for full suppression of basal lipolysis, despite retaining CGI-58 binding, linking PLIN1 truncation to familial partial lipodystrophy.","evidence":"Stable expression of WT vs. 439fs PLIN1 in preadipocytes with lipolysis, ABHD5 binding, and droplet size readouts","pmids":["25114292"],"confidence":"High","gaps":["How the C-terminal truncation uncouples CGI-58 binding from lipolysis suppression is mechanistically unresolved","Whether other PLIN1 mutations produce similar phenotypes not tested"]},{"year":2017,"claim":"Epigenetic regulation of PLIN1 was established: promoter CpG methylation inversely controls PLIN1 expression and thereby basal lipolysis in human adipocytes, providing a mechanism linking obesity-associated epigenetic changes to lipolytic dysregulation.","evidence":"CpG methylation array, methylated vs. unmethylated luciferase reporter, DNMT inhibitor treatment increasing PLIN1 mRNA/protein in human adipocytes","pmids":["28860604"],"confidence":"High","gaps":["Identity of DNA methyltransferases responsible not determined","Causal direction in obesity (whether methylation causes or results from altered lipolysis) not resolved"]},{"year":2019,"claim":"A conserved role for PLIN1 in connecting lipid droplets to the cytoskeleton was uncovered: the C. elegans ortholog MDT-28/PLIN-1 directly binds dynein light chain DLC-1 to mediate LD–microtubule interaction and regulate droplet distribution.","evidence":"Forward genetic screen, yeast two-hybrid and pull-down with domain mapping, fluorescence imaging in C. elegans","pmids":["31624276"],"confidence":"Medium","gaps":["Whether mammalian PLIN1 similarly binds dynein light chain is untested","Functional consequences of disrupted LD distribution on lipolysis not addressed"]},{"year":2020,"claim":"CRISPR knockout of PLIN1 in 3T3-L1 adipocytes confirmed it as essential for restraining basal lipolysis and maintaining unilocular droplet morphology, and revealed compensatory upregulation of HSL and ATGL.","evidence":"CRISPR/Cas9 KO in 3T3-L1 adipocytes with glycerol release, TG quantification, Oil Red O staining, Western blot, RT-PCR","pmids":["32748596"],"confidence":"Medium","gaps":["Whether HSL/ATGL upregulation is transcriptional compensation or post-translational is unclear","No rescue experiment reported"]},{"year":2020,"claim":"Transcriptional regulation of PLIN1 was mapped: E2F1, PLAG1, and C/EBPβ activate the PLIN1 core promoter while SMAD3 represses it, placing PLIN1 expression under combinatorial transcription factor control.","evidence":"Promoter deletion and luciferase reporter assays, site-directed mutagenesis, siRNA knockdown, and EMSA in bovine adipocytes","pmids":["31981700"],"confidence":"Medium","gaps":["Validation in human adipocytes lacking","In vivo chromatin occupancy (ChIP) not performed"]},{"year":2022,"claim":"PLIN1 was shown to function outside adipocytes: overexpression in M1 macrophages increased lipid droplet size and suppressed pro-inflammatory gene expression, establishing PLIN1 as a modulator of macrophage inflammatory polarity through lipid storage.","evidence":"PLIN1 overexpression and siRNA silencing in human macrophages with RT-PCR for TNFA, MMP2, ABCA1, ABCG1; immunohistochemistry of carotid plaques","pmids":["35662076"],"confidence":"Medium","gaps":["Mechanism linking increased LD size to transcriptional changes in macrophages is unknown","Single lab, no in vivo macrophage-specific manipulation"]},{"year":2024,"claim":"In vivo kinetic studies in PLIN1-mutated familial partial lipodystrophy patients revealed that hypertriglyceridemia results from decreased VLDL/IDL catabolism rather than overproduction, mechanistically linked to reduced circulating LPL mass from diminished adipose stores.","evidence":"Stable isotope tracer lipoprotein kinetic study, plasma LPL mass, and adipose LPL expression in n=6 FPL patients vs. controls","pmids":["38899472"],"confidence":"Medium","gaps":["Small patient cohort","Whether LPL secretion defect is direct or secondary to adipose loss is not resolved"]},{"year":2025,"claim":"Biophysical characterization revealed the PLIN1 C-terminal domain is an intrinsically disordered region with a molecular recognition feature (EPESE, residues 413–417) that likely mediates CGI-58 binding, explaining how this domain functions as a conformationally flexible interaction hub.","evidence":"Circular dichroism spectroscopy, SDS micelle interaction assay, bioinformatic disorder prediction on mouse PLIN1C","pmids":["40109298"],"confidence":"Medium","gaps":["MoRF–CGI-58 interaction not validated by mutagenesis","No high-resolution structural model of the PLIN1–CGI-58 complex"]},{"year":null,"claim":"Key unresolved questions include the structural basis of the PLIN1–CGI-58 interaction, how PKA phosphorylation conformationally triggers CGI-58 release, whether the dynein light chain interaction is conserved in mammals, and the mechanism by which PLIN1 modulates macrophage inflammatory signaling.","evidence":"","pmids":[],"confidence":"Low","gaps":["No high-resolution structure of PLIN1 or PLIN1–CGI-58 complex","Phosphorylation-induced conformational change not directly visualized","Mammalian PLIN1–dynein interaction not tested","Mechanism of PLIN1-mediated transcriptional effects in macrophages unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[0,2,6,10]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[1,2,6]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[1,2,10]}],"localization":[{"term_id":"GO:0005811","term_label":"lipid droplet","supporting_discovery_ids":[0,2,6,11,12]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[5]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[1,2,6,9]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,8]}],"complexes":[],"partners":["ABHD5","CIDEC","PNPLA2","BSCL2"],"other_free_text":[]},"mechanistic_narrative":"PLIN1 (perilipin-1) is an adipocyte-specific lipid droplet coat protein that serves as the master gatekeeper of triglyceride hydrolysis by integrating hormonal signals with the lipolytic machinery at the droplet surface. Under basal conditions, PLIN1 suppresses lipolysis by sequestering the ATGL co-activator CGI-58/ABHD5; PKA-mediated phosphorylation of PLIN1 releases CGI-58 to activate ATGL-driven triglyceride hydrolysis, and the intrinsically disordered C-terminal domain—including a molecular recognition feature at residues 413–417—is required for CGI-58 binding and full suppression of basal lipolysis [PMID:23408028, PMID:25114292, PMID:40109298]. PLIN1 also interacts with FSP27/CIDEC to promote unilocular lipid droplet formation, and its recruitment to the droplet surface depends on seipin (BSCL2); loss of PLIN1 or its mislocalization leads to enhanced lipolysis, smaller multilocular droplets, and—in the case of PLIN1-mutated familial partial lipodystrophy—hypertriglyceridemia driven by impaired VLDL/IDL catabolism [PMID:23399566, PMID:32748596, PMID:38899472]. PLIN1 transcription in adipocytes is activated by E2F1, PLAG1, and C/EBPβ, repressed by SMAD3, and negatively regulated by promoter CpG methylation [PMID:31981700, PMID:28860604]."},"prefetch_data":{"uniprot":{"accession":"O60240","full_name":"Perilipin-1","aliases":["Lipid droplet-associated protein"],"length_aa":522,"mass_kda":56.0,"function":"Modulator of adipocyte lipid metabolism. Coats lipid storage droplets to protect them from breakdown by hormone-sensitive lipase (HSL). Its absence may result in leanness. Plays a role in unilocular lipid droplet formation by activating CIDEC. Their interaction promotes lipid droplet enlargement and directional net neutral lipid transfer. May modulate lipolysis and triglyceride levels","subcellular_location":"Endoplasmic reticulum; Lipid droplet","url":"https://www.uniprot.org/uniprotkb/O60240/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PLIN1","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/PLIN1","total_profiled":1310},"omim":[{"mim_id":"619894","title":"ABHYDROLASE DOMAIN-CONTAINING PROTEIN 15; ABHD15","url":"https://www.omim.org/entry/619894"},{"mim_id":"613877","title":"LIPODYSTROPHY, FAMILIAL PARTIAL, TYPE 4; FPLD4","url":"https://www.omim.org/entry/613877"},{"mim_id":"613248","title":"PERILIPIN 5; PLIN5","url":"https://www.omim.org/entry/613248"},{"mim_id":"613247","title":"PERILIPIN 4; PLIN4","url":"https://www.omim.org/entry/613247"},{"mim_id":"609888","title":"LEPROSY, SUSCEPTIBILITY TO, 1; LPRS1","url":"https://www.omim.org/entry/609888"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Uncertain","locations":[{"location":"Peroxisomes","reliability":"Uncertain"}],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"adipose tissue","ntpm":898.1},{"tissue":"breast","ntpm":459.5}],"url":"https://www.proteinatlas.org/search/PLIN1"},"hgnc":{"alias_symbol":[],"prev_symbol":["PLIN"]},"alphafold":{"accession":"O60240","domains":[{"cath_id":"-","chopping":"21-107","consensus_level":"high","plddt":72.2724,"start":21,"end":107},{"cath_id":"-","chopping":"183-194_219-248","consensus_level":"medium","plddt":70.7583,"start":183,"end":248}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O60240","model_url":"https://alphafold.ebi.ac.uk/files/AF-O60240-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O60240-F1-predicted_aligned_error_v6.png","plddt_mean":54.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PLIN1","jax_strain_url":"https://www.jax.org/strain/search?query=PLIN1"},"sequence":{"accession":"O60240","fasta_url":"https://rest.uniprot.org/uniprotkb/O60240.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O60240/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O60240"}},"corpus_meta":[{"pmid":"23399566","id":"PMC_23399566","title":"FSP27 and PLIN1 interaction promotes the formation of large lipid droplets in human adipocytes.","date":"2013","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/23399566","citation_count":112,"is_preprint":false},{"pmid":"15355432","id":"PMC_15355432","title":"Genetic variation at the perilipin (PLIN) locus is associated with obesity-related phenotypes in White women.","date":"2004","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/15355432","citation_count":82,"is_preprint":false},{"pmid":"23408028","id":"PMC_23408028","title":"Skeletal muscle PLIN proteins, ATGL and CGI-58, interactions at rest and following stimulated contraction.","date":"2013","source":"American journal of physiology. Regulatory, integrative and comparative physiology","url":"https://pubmed.ncbi.nlm.nih.gov/23408028","citation_count":76,"is_preprint":false},{"pmid":"25114292","id":"PMC_25114292","title":"Clinical and molecular characterization of a novel PLIN1 frameshift mutation identified in patients with familial partial lipodystrophy.","date":"2014","source":"Diabetes","url":"https://pubmed.ncbi.nlm.nih.gov/25114292","citation_count":64,"is_preprint":false},{"pmid":"22667335","id":"PMC_22667335","title":"Perilipin family (PLIN) proteins in human skeletal muscle: the effect of sex, obesity, and endurance training.","date":"2012","source":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","url":"https://pubmed.ncbi.nlm.nih.gov/22667335","citation_count":61,"is_preprint":false},{"pmid":"29617344","id":"PMC_29617344","title":"A Key Gene, PLIN1, Can Affect Porcine Intramuscular Fat Content Based on Transcriptome Analysis.","date":"2018","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/29617344","citation_count":56,"is_preprint":false},{"pmid":"15770500","id":"PMC_15770500","title":"Intragenic linkage disequilibrium structure of the human perilipin gene (PLIN) and haplotype association with increased obesity risk in a multiethnic Asian population.","date":"2005","source":"Journal of molecular medicine (Berlin, Germany)","url":"https://pubmed.ncbi.nlm.nih.gov/15770500","citation_count":56,"is_preprint":false},{"pmid":"31981700","id":"PMC_31981700","title":"Function and characterization of the promoter region of perilipin 1 (PLIN1): Roles of E2F1, PLAG1, C/EBPβ, and SMAD3 in bovine adipocytes.","date":"2020","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/31981700","citation_count":36,"is_preprint":false},{"pmid":"33105676","id":"PMC_33105676","title":"Overexpression of PLIN1 Promotes Lipid Metabolism in Bovine Adipocytes.","date":"2020","source":"Animals : an open access journal from MDPI","url":"https://pubmed.ncbi.nlm.nih.gov/33105676","citation_count":35,"is_preprint":false},{"pmid":"32012433","id":"PMC_32012433","title":"Plin-amiR, a pre-microRNA-based technology for controlling herbivorous insect pests.","date":"2020","source":"Plant biotechnology journal","url":"https://pubmed.ncbi.nlm.nih.gov/32012433","citation_count":35,"is_preprint":false},{"pmid":"18812483","id":"PMC_18812483","title":"Effects of perilipin (PLIN) gene variation on metabolic syndrome risk and weight loss in obese children and adolescents.","date":"2008","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/18812483","citation_count":33,"is_preprint":false},{"pmid":"31504636","id":"PMC_31504636","title":"Diagnostic Challenge in PLIN1-Associated Familial Partial Lipodystrophy.","date":"2019","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/31504636","citation_count":31,"is_preprint":false},{"pmid":"9521880","id":"PMC_9521880","title":"Isolation and chromosomal mapping of the human homolog of perilipin (PLIN), a rat adipose tissue-specific gene, by differential display method.","date":"1998","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/9521880","citation_count":31,"is_preprint":false},{"pmid":"32110804","id":"PMC_32110804","title":"Long non-coding RNA ARAP1-AS1 accelerates cell proliferation and migration in breast cancer through miR-2110/HDAC2/PLIN1 axis.","date":"2020","source":"Bioscience reports","url":"https://pubmed.ncbi.nlm.nih.gov/32110804","citation_count":29,"is_preprint":false},{"pmid":"22012700","id":"PMC_22012700","title":"Subcellular localization of skeletal muscle lipid droplets and PLIN family proteins OXPAT and ADRP at rest and following contraction in rat soleus muscle.","date":"2011","source":"American journal of physiology. 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Patients.","date":"2017","source":"Obesity surgery","url":"https://pubmed.ncbi.nlm.nih.gov/27376365","citation_count":23,"is_preprint":false},{"pmid":"30020498","id":"PMC_30020498","title":"PLIN1 Haploinsufficiency Is Not Associated With Lipodystrophy.","date":"2018","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/30020498","citation_count":23,"is_preprint":false},{"pmid":"15601966","id":"PMC_15601966","title":"Polymorphisms in PLIN and hypertension combined with obesity and lipid profiles in Han Chinese.","date":"2004","source":"Obesity research","url":"https://pubmed.ncbi.nlm.nih.gov/15601966","citation_count":19,"is_preprint":false},{"pmid":"28860604","id":"PMC_28860604","title":"Epigenetic Regulation of PLIN 1 in Obese Women and its Relation to Lipolysis.","date":"2017","source":"Scientific 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Co-expression of both proteins increases average lipid droplet size and promotes unilocular adipocyte formation without additively reducing lipolysis beyond individual effects.\",\n      \"method\": \"Co-immunoprecipitation, co-localization by fluorescence microscopy, domain mapping (truncation constructs), triglyceride content and glycerol release assays in human primary adipocytes\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP with domain mapping, functional lipolysis readout, replicated in human primary adipocytes\",\n      \"pmids\": [\"23399566\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"In adipocytes, PLIN1 regulates lipolysis by sequestering CGI-58 (ABHD5), an activator of ATGL; upon PKA-mediated phosphorylation of PLIN1, CGI-58 is released to fully activate ATGL and initiate triglyceride hydrolysis.\",\n      \"method\": \"Co-immunoprecipitation of PLIN1 with CGI-58 and ATGL in rat soleus (referenced as established adipocyte mechanism) and contrasted with skeletal muscle PLIN proteins\",\n      \"journal\": \"American journal of physiology. Regulatory, integrative and comparative physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — mechanism described via co-IP context in muscle study; foundational adipocyte mechanism supported across multiple studies\",\n      \"pmids\": [\"23408028\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"A heterozygous frameshift mutation at the carboxy-terminus of PLIN1 (439fs) produces a mutant protein that binds and stabilizes ABHD5 (CGI-58) expression but fails to inhibit basal lipolysis as effectively as wild-type PLIN1, and is associated with smaller lipid droplets in stably transfected preadipocytes, demonstrating that the C-terminal domain of PLIN1 is required for full suppression of basal lipolysis.\",\n      \"method\": \"Stable transfection of preadipocytes with frameshift mutant vs. WT PLIN1, lipolysis assay (glycerol release), ABHD5 binding/expression analysis, lipid droplet size measurement\",\n      \"journal\": \"Diabetes\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function mutant with specific cellular phenotype plus binding assay, multiple orthogonal readouts\",\n      \"pmids\": [\"25114292\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Human PLIN1 encodes a 522-amino-acid protein with 79% identity to rat perilipin; Northern blot showed adipose-tissue-specific expression among 20 adult human tissues; chromosomal location mapped to 15q26.\",\n      \"method\": \"Differential display cloning, Northern blot, fluorescence in situ hybridization (FISH)\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct molecular cloning and expression mapping; localization without functional manipulation\",\n      \"pmids\": [\"9521880\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"The PLIN1 gene promoter is subject to DNA methylation in human adipocytes; CpG methylation of the PLIN1 promoter is inversely correlated with PLIN1 mRNA expression and basal lipolysis in obese women. Methylated PLIN1 promoter reporter constructs show decreased activity in hMSC-derived adipocytes, and treatment with a DNA methyltransferase inhibitor increases PLIN1 mRNA and protein levels.\",\n      \"method\": \"CpG methylation array, reporter gene (luciferase) assay with methylated vs. unmethylated PLIN1 promoter construct, DNMT inhibitor treatment, correlation analysis with glycerol-release lipolysis assay\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — functional reporter assay plus pharmacological intervention plus correlative methylation data, multiple orthogonal methods\",\n      \"pmids\": [\"28860604\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"In C. elegans, the PLIN1 ortholog MDT-28/PLIN-1 mediates interaction between lipid droplets and microtubules via direct binding to the dynein light chain DLC-1; yeast two-hybrid and pull-down assays mapped the DLC-1-binding regions to amino acids 1-210 and 275-415 of MDT-28/PLIN-1. Fluorescence imaging confirmed that MDT-28/PLIN-1 mediates LD-microtubule contact, regulating LD distribution.\",\n      \"method\": \"Forward genetic screen, yeast two-hybrid, pull-down assay, fluorescence imaging in C. elegans\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — yeast two-hybrid plus pull-down with domain mapping, functional imaging; C. elegans ortholog, context consistent with mammalian PLIN1\",\n      \"pmids\": [\"31624276\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PLIN1 knockout in 3T3-L1 adipocytes (via CRISPR/Cas9) enhances basal lipolysis, as shown by increased glycerol release and decreased triglyceride content, accompanied by upregulation of HSL and ATGL mRNA and protein. Lipid droplet morphology shifts from unilocular to smaller, multiple droplets. PPARγ and FSP27 expression was unchanged.\",\n      \"method\": \"CRISPR/Cas9 knockout in 3T3-L1 adipocytes, glycerol/TG enzymatic assay, Oil Red O staining, Western blot, RT-PCR\",\n      \"journal\": \"Sheng wu gong cheng xue bao = Chinese journal of biotechnology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with specific phenotypic readout (lipolysis) and multiple molecular markers\",\n      \"pmids\": [\"32748596\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In bovine adipocytes, the PLIN1 core promoter region (-209/-17 bp) is activated by transcription factors E2F1, PLAG1, and C/EBPβ, and repressed by SMAD3, as demonstrated by promoter deletion assays, luciferase reporter assays with mutated binding sites, siRNA knockdown, and EMSA.\",\n      \"method\": \"Promoter deletion constructs, luciferase reporter assay, site-directed mutagenesis, siRNA knockdown, EMSA\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (reporter assay, mutagenesis, EMSA, siRNA) in bovine adipocytes\",\n      \"pmids\": [\"31981700\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"PLIN1 overexpression in M1 macrophages increases lipid droplet size and reduces expression of TNFA, MMP2, ABCA1, and ABCG1; PLIN1 silencing in M2 macrophages has opposite effects on LD size and gene expression, establishing PLIN1 as a regulator of macrophage inflammatory polarity through lipid storage modulation.\",\n      \"method\": \"PLIN1 overexpression and siRNA silencing in cultured human macrophages, immunohistochemistry of carotid endarterectomy plaques, quantitative RT-PCR\",\n      \"journal\": \"Journal of atherosclerosis and thrombosis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — gain- and loss-of-function with specific molecular readouts; single lab\",\n      \"pmids\": [\"35662076\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Hypertriglyceridemia in PLIN1-related familial partial lipodystrophy results from markedly decreased catabolism of VLDL and IDL (reduced indirect fractional catabolic rates of VLDL-apoB100 and IDL-apoB100), not from increased VLDL production. Plasma LPL mass was significantly lower in patients with PLIN1-mutated FPL than controls, despite similar LPL protein expression in adipose tissue, indicating impaired LPL availability due to reduced adipose mass.\",\n      \"method\": \"In vivo lipoprotein kinetic study (stable isotope tracer), plasma LPL mass measurement, LPL mRNA and protein expression in adipose tissue biopsy\",\n      \"journal\": \"Arteriosclerosis, thrombosis, and vascular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo kinetic study with mechanistic quantification, n=6 patients vs. controls\",\n      \"pmids\": [\"38899472\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"The C-terminal domain of mouse PLIN1 (mPLIN1C) behaves as an intrinsically disordered region (IDR) with coil-like or pre-molten globule character; circular dichroism spectroscopy shows predominance of disordered secondary structure. Interaction with SDS micelles induces a conformational transition, and the EPESE sequence (residues 413-417) was identified as a potential molecular recognition feature (MoRF) for partner-molecule binding (including CGI-58).\",\n      \"method\": \"Circular dichroism spectroscopy, bioinformatic disorder prediction, SDS micelle interaction assay\",\n      \"journal\": \"Biochemistry and biophysics reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — biophysical characterization with CD spectroscopy and micelle interaction; single study, no mutagenesis validation\",\n      \"pmids\": [\"40109298\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Seipin (BSCL2) is required for recruiting PLIN1 to the lipid droplet surface in human adipocytes; without seipin, lipid droplet biogenesis still occurs but PLIN1 fails to localize to droplets, resulting in enhanced lipolysis, ceramide accumulation, and adipocyte de-differentiation into a progenitor-like state. This identifies seipin as an upstream regulator of PLIN1 LD recruitment that enforces adipocyte identity.\",\n      \"method\": \"BSCL2 knockout in human adipocyte progenitor cells, live-cell imaging of PLIN1 localization, lipolysis assay, lipid/ceramide quantification, in vivo xenograft differentiation\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with direct localization imaging, multiple functional readouts (lipolysis, ceramide, de-differentiation), in vivo validation\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"During differentiation of 3T3 pre-adipocytes into adipocytes, PLIN1—a high-affinity LD protein—becomes predominantly recruited to lipid droplets and displaces other ER proteins through steric exclusion, demonstrating lateral protein-protein exclusion as a mechanism shaping the LD proteome.\",\n      \"method\": \"Ex vivo quantitative LD partitioning assay, fluorescence imaging during 3T3-L1 adipocyte differentiation, competition assay between LD-targeting proteins\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — novel ex vivo assay with functional imaging; preprint, not yet peer-reviewed\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"PLIN1 (perilipin-1) is an adipocyte lipid droplet coat protein that suppresses basal lipolysis by sequestering the ATGL co-activator CGI-58/ABHD5 at the droplet surface; upon PKA-mediated phosphorylation, PLIN1 releases CGI-58 to activate ATGL-driven triglyceride hydrolysis. PLIN1 recruitment to the droplet surface is seipin-dependent, its C-terminal domain (which is intrinsically disordered) mediates CGI-58 binding and lipolysis control, it interacts with FSP27/CIDEC to regulate droplet size, it controls droplet-microtubule interaction via dynein light chain (in C. elegans), and its transcription is regulated by E2F1, PLAG1, C/EBPβ, SMAD3, and by promoter DNA methylation.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"PLIN1 (perilipin-1) is an adipocyte-specific lipid droplet coat protein that serves as the master gatekeeper of triglyceride hydrolysis by integrating hormonal signals with the lipolytic machinery at the droplet surface. Under basal conditions, PLIN1 suppresses lipolysis by sequestering the ATGL co-activator CGI-58/ABHD5; PKA-mediated phosphorylation of PLIN1 releases CGI-58 to activate ATGL-driven triglyceride hydrolysis, and the intrinsically disordered C-terminal domain—including a molecular recognition feature at residues 413–417—is required for CGI-58 binding and full suppression of basal lipolysis [PMID:23408028, PMID:25114292, PMID:40109298]. PLIN1 also interacts with FSP27/CIDEC to promote unilocular lipid droplet formation, and its recruitment to the droplet surface depends on seipin (BSCL2); loss of PLIN1 or its mislocalization leads to enhanced lipolysis, smaller multilocular droplets, and—in the case of PLIN1-mutated familial partial lipodystrophy—hypertriglyceridemia driven by impaired VLDL/IDL catabolism [PMID:23399566, PMID:32748596, PMID:38899472]. PLIN1 transcription in adipocytes is activated by E2F1, PLAG1, and C/EBPβ, repressed by SMAD3, and negatively regulated by promoter CpG methylation [PMID:31981700, PMID:28860604].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Cloning of human PLIN1 established it as a highly conserved, adipose-tissue-specific gene, providing the molecular foundation for studying its lipid droplet functions.\",\n      \"evidence\": \"Differential display cloning, Northern blot across 20 human tissues, and FISH mapping to 15q26\",\n      \"pmids\": [\"9521880\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional data on lipolysis or lipid droplet association at this stage\", \"Protein localization to lipid droplets not directly demonstrated\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"The mechanism by which PLIN1 suppresses basal lipolysis was defined: PLIN1 sequesters the ATGL co-activator CGI-58 on the droplet surface, and PKA phosphorylation of PLIN1 releases CGI-58 to activate ATGL, establishing the canonical lipolysis-gating model.\",\n      \"evidence\": \"Co-immunoprecipitation of PLIN1 with CGI-58 and ATGL in adipocyte and muscle contexts\",\n      \"pmids\": [\"23408028\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of CGI-58–PLIN1 interaction unknown\", \"Precise phosphorylation sites mediating release not mapped in this study\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"PLIN1 was shown to physically interact with FSP27/CIDEC and cooperate in promoting unilocular lipid droplet formation in adipocytes, revealing a second effector partnership beyond CGI-58.\",\n      \"evidence\": \"Co-immunoprecipitation with domain mapping (FSP27 aa 120–220 binds PLIN1), lipid droplet size and lipolysis assays in human primary adipocytes\",\n      \"pmids\": [\"23399566\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"PLIN1 domain mediating FSP27 binding not mapped\", \"Mechanism by which the PLIN1–FSP27 complex enlarges droplets is unclear\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"A C-terminal frameshift mutation (439fs) demonstrated that the C-terminal domain of PLIN1 is essential for full suppression of basal lipolysis, despite retaining CGI-58 binding, linking PLIN1 truncation to familial partial lipodystrophy.\",\n      \"evidence\": \"Stable expression of WT vs. 439fs PLIN1 in preadipocytes with lipolysis, ABHD5 binding, and droplet size readouts\",\n      \"pmids\": [\"25114292\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How the C-terminal truncation uncouples CGI-58 binding from lipolysis suppression is mechanistically unresolved\", \"Whether other PLIN1 mutations produce similar phenotypes not tested\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Epigenetic regulation of PLIN1 was established: promoter CpG methylation inversely controls PLIN1 expression and thereby basal lipolysis in human adipocytes, providing a mechanism linking obesity-associated epigenetic changes to lipolytic dysregulation.\",\n      \"evidence\": \"CpG methylation array, methylated vs. unmethylated luciferase reporter, DNMT inhibitor treatment increasing PLIN1 mRNA/protein in human adipocytes\",\n      \"pmids\": [\"28860604\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of DNA methyltransferases responsible not determined\", \"Causal direction in obesity (whether methylation causes or results from altered lipolysis) not resolved\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"A conserved role for PLIN1 in connecting lipid droplets to the cytoskeleton was uncovered: the C. elegans ortholog MDT-28/PLIN-1 directly binds dynein light chain DLC-1 to mediate LD–microtubule interaction and regulate droplet distribution.\",\n      \"evidence\": \"Forward genetic screen, yeast two-hybrid and pull-down with domain mapping, fluorescence imaging in C. elegans\",\n      \"pmids\": [\"31624276\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether mammalian PLIN1 similarly binds dynein light chain is untested\", \"Functional consequences of disrupted LD distribution on lipolysis not addressed\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"CRISPR knockout of PLIN1 in 3T3-L1 adipocytes confirmed it as essential for restraining basal lipolysis and maintaining unilocular droplet morphology, and revealed compensatory upregulation of HSL and ATGL.\",\n      \"evidence\": \"CRISPR/Cas9 KO in 3T3-L1 adipocytes with glycerol release, TG quantification, Oil Red O staining, Western blot, RT-PCR\",\n      \"pmids\": [\"32748596\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether HSL/ATGL upregulation is transcriptional compensation or post-translational is unclear\", \"No rescue experiment reported\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Transcriptional regulation of PLIN1 was mapped: E2F1, PLAG1, and C/EBPβ activate the PLIN1 core promoter while SMAD3 represses it, placing PLIN1 expression under combinatorial transcription factor control.\",\n      \"evidence\": \"Promoter deletion and luciferase reporter assays, site-directed mutagenesis, siRNA knockdown, and EMSA in bovine adipocytes\",\n      \"pmids\": [\"31981700\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Validation in human adipocytes lacking\", \"In vivo chromatin occupancy (ChIP) not performed\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"PLIN1 was shown to function outside adipocytes: overexpression in M1 macrophages increased lipid droplet size and suppressed pro-inflammatory gene expression, establishing PLIN1 as a modulator of macrophage inflammatory polarity through lipid storage.\",\n      \"evidence\": \"PLIN1 overexpression and siRNA silencing in human macrophages with RT-PCR for TNFA, MMP2, ABCA1, ABCG1; immunohistochemistry of carotid plaques\",\n      \"pmids\": [\"35662076\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking increased LD size to transcriptional changes in macrophages is unknown\", \"Single lab, no in vivo macrophage-specific manipulation\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"In vivo kinetic studies in PLIN1-mutated familial partial lipodystrophy patients revealed that hypertriglyceridemia results from decreased VLDL/IDL catabolism rather than overproduction, mechanistically linked to reduced circulating LPL mass from diminished adipose stores.\",\n      \"evidence\": \"Stable isotope tracer lipoprotein kinetic study, plasma LPL mass, and adipose LPL expression in n=6 FPL patients vs. controls\",\n      \"pmids\": [\"38899472\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Small patient cohort\", \"Whether LPL secretion defect is direct or secondary to adipose loss is not resolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Biophysical characterization revealed the PLIN1 C-terminal domain is an intrinsically disordered region with a molecular recognition feature (EPESE, residues 413–417) that likely mediates CGI-58 binding, explaining how this domain functions as a conformationally flexible interaction hub.\",\n      \"evidence\": \"Circular dichroism spectroscopy, SDS micelle interaction assay, bioinformatic disorder prediction on mouse PLIN1C\",\n      \"pmids\": [\"40109298\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"MoRF–CGI-58 interaction not validated by mutagenesis\", \"No high-resolution structural model of the PLIN1–CGI-58 complex\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of the PLIN1–CGI-58 interaction, how PKA phosphorylation conformationally triggers CGI-58 release, whether the dynein light chain interaction is conserved in mammals, and the mechanism by which PLIN1 modulates macrophage inflammatory signaling.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No high-resolution structure of PLIN1 or PLIN1–CGI-58 complex\", \"Phosphorylation-induced conformational change not directly visualized\", \"Mammalian PLIN1–dynein interaction not tested\", \"Mechanism of PLIN1-mediated transcriptional effects in macrophages unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [0, 2, 6, 10]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [1, 2, 6]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [1, 2, 10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005811\", \"supporting_discovery_ids\": [0, 2, 6, 11, 12]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [1, 2, 6, 9]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 8]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"ABHD5\",\n      \"CIDEC\",\n      \"PNPLA2\",\n      \"BSCL2\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}