{"gene":"VPS18","run_date":"2026-04-28T23:00:23","timeline":{"discoveries":[{"year":1991,"finding":"Yeast PEP3/VPS18 encodes a 107-kDa hydrophilic vacuolar peripheral membrane protein required for vacuolar biogenesis; loss-of-function results in accumulation of small vesicles instead of normal vacuoles and defects in delivery of vacuolar hydrolases (protease A, protease B, carboxypeptidase Y).","method":"Complementation cloning, deletion/disruption alleles, subcellular fractionation of PEP3::SUC2 fusion, fluorescence and electron microscopy","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (genetic complementation, fractionation, EM/fluorescence microscopy) in foundational study","pmids":["1944264"],"is_preprint":false},{"year":2001,"finding":"Human VPS18 (and VPS11, VPS16, VPS33) are homologs of yeast class C VPS genes; the four proteins are expressed in human tissues and are candidates for involvement in lysosomal protein delivery pathways conserved from yeast to mammals.","method":"Molecular cloning, sequence analysis, expression pattern determination","journal":"Gene","confidence":"Medium","confidence_rationale":"Tier 3 — sequence/expression characterization; single lab, no functional reconstitution","pmids":["11250079"],"is_preprint":false},{"year":2005,"finding":"Zebrafish vps18 mutation (class C VPS gene) causes hepatomegaly with vesicle-filled hepatocytes attributable to failure of endosomal-lysosomal trafficking, defects in bile canaliculi, and biliary paucity, demonstrating that vps18 is required for vesicle trafficking to both the lysosomal and hepatocyte apical membrane compartments.","method":"Insertional mutagenesis screen, histology, electron microscopy, live imaging in zebrafish embryos","journal":"Development (Cambridge, England)","confidence":"High","confidence_rationale":"Tier 2 — genetic loss-of-function with multiple defined cellular phenotypes in a vertebrate model organism","pmids":["16000385"],"is_preprint":false},{"year":2006,"finding":"Zebrafish vps18 mutant (retroviral insertion in exon 4 disrupting clathrin repeat and RING finger domains) shows severe reduction in melanosomes in retinal pigmented epithelium with accumulation of immature melanosomes, establishing that Vps18 is required for melanosome biogenesis via its role in the HOPS complex during vesicular traffic.","method":"Insertional mutagenesis, RT-PCR of splicing variants, histology, optokinetic response assay in zebrafish larvae","journal":"Pigment cell research","confidence":"Medium","confidence_rationale":"Tier 2 — defined loss-of-function phenotype with molecular characterization of truncation; single lab","pmids":["16827750"],"is_preprint":false},{"year":2008,"finding":"C. elegans VPS-18 functions in engulfing cells to mediate lysosome biogenesis and phagosome-lysosome fusion; vps-18 deletion causes accumulation of undegraded apoptotic cell corpses due to failure of phagosome fusion with lysosomes.","method":"Deletion mutant analysis, fluorescence microscopy of endosomal/lysosomal markers, phagosome-lysosome fusion assay in C. elegans","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 — clean KO with defined cellular phenotype and direct fusion assay, multiple orthogonal readouts","pmids":["18923146"],"is_preprint":false},{"year":2008,"finding":"The class C Vps complex (including Vps18) interacts with UVRAG-Beclin1 to stimulate Rab7 GTPase activity and promote autophagosome fusion with late endosomes/lysosomes as well as endosome-endosome fusion.","method":"Co-immunoprecipitation, Rab7 GTPase activity assay, autophagic flux assays in mammalian cells","journal":"Nature cell biology","confidence":"High","confidence_rationale":"Tier 1-2 — biochemical activity assay plus Co-IP and functional flux assay; highly cited","pmids":["18552835"],"is_preprint":false},{"year":2011,"finding":"Human Vps18 and its yeast ortholog are required for efficient HIV-1 Gag-induced viruslike particle release and infectious virion production; depletion of hVps18 in human cells reduces infectious HIV-1 particle yield, placing Vps18-dependent trafficking in the HIV-1 budding pathway.","method":"Yeast genetic screen, siRNA knockdown in human cells, VLP release assay, viral infectivity measurement","journal":"Journal of virology","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function in two systems with quantitative virion production readout; single lab","pmids":["21450827"],"is_preprint":false},{"year":2012,"finding":"Conditional knockout of Vps18 in neural cells (Nestin-Cre) causes neurodegeneration by blocking multiple vesicle transport pathways to the lysosome including autophagy, endocytosis, and biosynthetic pathways; Vps18 deficiency also causes β1 integrin upregulation due to lysosomal dysfunction, contributing to neuronal migration defects that are partially rescued by β1 integrin knockdown.","method":"Conditional KO mice (Vps18-F/F; Nestin-Cre), immunohistochemistry, Western blot, autophagy/endocytosis flux assays, siRNA rescue experiments","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — in vivo conditional KO with multiple mechanistic readouts and epistasis rescue experiment","pmids":["22854957"],"is_preprint":false},{"year":2012,"finding":"Vps18 deficiency in Purkinje cells blocks dendrite development by preventing lysosomal degradation of Lysyl Oxidase (Lox); Lox protein accumulates in Vps18-deficient cerebellum, linking lysosomal degradative function to dendritogenesis.","method":"Conditional KO mice, immunohistochemistry, Western blot for Lox in cerebellum vs. cortex","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 — defined substrate accumulation in specific cell type with KO model; single lab","pmids":["22699122"],"is_preprint":false},{"year":2014,"finding":"The HOPS complex (including VPS18) interacts with autophagosomal SNARE syntaxin 17 (STX17) to promote autophagosome-lysosome fusion; knockdown of HOPS subunits blocks autophagic flux and causes accumulation of STX17/LC3-positive autophagosomes.","method":"Immunoprecipitation, mass spectrometry, siRNA knockdown, autophagic flux assays in mammalian cells","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP identifying specific interaction, functional knockdown with defined phenotype; replicated","pmids":["24554770"],"is_preprint":false},{"year":2017,"finding":"Human VPS18 RING domain directly interacts with the RING domain of VPS41 to form a stable heterodimer required for VPS41 recruitment to the core HOPS complex; this RING-RING interaction is unique to metazoans as yeast Vps41 lacks a C-terminal zinc-finger motif.","method":"Biochemical pulldown, co-immunoprecipitation with endogenous HOPS, domain truncation/mutant analysis","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1-2 — direct biochemical demonstration of RING-RING heterodimer with functional integration into endogenous complex","pmids":["28931724"],"is_preprint":false},{"year":2019,"finding":"Vps11 and Vps18 (shared HOPS/CORVET subunits) function as E3 ubiquitin ligases; overexpression perturbs ubiquitination in signal transduction pathways including Wnt, ERα, and NFκB; specifically, Vps11/18-mediated ubiquitination of scaffold protein PELP1 impairs ERα activation by c-Src.","method":"E3 ligase activity assays, ubiquitination assays, Co-IP, overexpression in Drosophila and mammalian cells, signaling pathway readouts","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1-2 — enzymatic activity demonstrated with specific substrate identified, multiple pathways validated across organisms","pmids":["31015428"],"is_preprint":false},{"year":2024,"finding":"VPS11/18 interact with PD-L1 in endosomal recycling and promote PD-L1 glycosylation and protein stability; VPS18 deficiency reduces PD-L1 surface levels and enhances antitumor immune response; VPS18 mediates trans-Golgi network recycling of PD-L1.","method":"Co-immunoprecipitation, siRNA/CRISPR knockdown, PD-L1 stability and glycosylation assays, in vivo tumor models, pharmacological inhibition","journal":"Science advances","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP interaction plus functional KO and pharmacological evidence; single lab","pmids":["39413192"],"is_preprint":false},{"year":2025,"finding":"VPS18 is required for phagosomal membrane integrity in Mycobacterium tuberculosis-infected macrophages; VPS18-knockout macrophages show increased phagosomal damage without impaired autophagy, Mtb grows more robustly, and antibiotic efficacy (pyrazinamide) is reduced; VPS18 colocalizes with Mtb-containing phagosomes shortly after infection.","method":"Genome-wide CRISPR screen, CRISPR KO, galectin-based phagosomal damage assay, live-cell imaging, antibiotic efficacy assay","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 2 — genome-wide unbiased screen plus validated KO with multiple mechanistic readouts","pmids":["39888996"],"is_preprint":false},{"year":2025,"finding":"Vps18 deficiency in LSL-K-Ras lung tumors elevates EGFR protein levels and activates ERK-MAPK signaling; expression of dominant-negative EGFR partially suppresses the tumor-promoting effects of Vps18 loss, establishing a Vps18-EGFR-ERK axis in lung tumorigenesis via lysosomal degradation of EGFR.","method":"Conditional KO in LSL-K-Ras mice, Western blot, EGFR dominant-negative rescue, ERK-MAPK pathway analysis","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo genetic model with epistasis rescue; single lab, single paper","pmids":["40615043"],"is_preprint":false},{"year":2026,"finding":"VPS18 deficiency in neutrophil progenitors causes CORVET/HOPS tethering complex instability, impaired vesicle dynamics with autophagosome accumulation (increased LC3B-II and p62), and premature apoptosis, resulting in a neutrophil maturation defect; heterozygous VPS18 stop-gain mutations in a human patient and in iPSC/zebrafish models cause neutropenia.","method":"CRISPR/Cas9 Hoxb8 cells, iPSC differentiation, TEM, LC3/p62 Western blot, zebrafish model, patient mutation characterization","journal":"Cell death & disease","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal models (cell line, iPSC, zebrafish, patient) with defined mechanistic readouts","pmids":["41526335"],"is_preprint":false}],"current_model":"VPS18 is a central scaffold subunit shared by the HOPS and CORVET membrane-tethering complexes that regulates multiple vesicular trafficking pathways to lysosomes/vacuoles—including endocytosis, autophagy, and biosynthetic routes—by facilitating SNARE-mediated membrane fusion; its C-terminal RING domain directly recruits VPS41 into HOPS, it functions as an E3 ubiquitin ligase to fine-tune signaling (e.g., ERα/PELP1, Wnt, NFκB), it promotes lysosomal degradation of substrates such as EGFR and Lysyl Oxidase to regulate cell proliferation and dendritogenesis, it maintains phagosomal membrane integrity against Mycobacterium tuberculosis, and it controls PD-L1 glycosylation and recycling through endosomal trafficking."},"narrative":{"teleology":[{"year":1991,"claim":"Identification of PEP3/VPS18 as a gene required for vacuolar biogenesis in yeast established that the protein is essential for vesicular delivery of hydrolases to the vacuole, founding the class C VPS pathway.","evidence":"Complementation cloning, gene disruption, subcellular fractionation, and electron microscopy in S. cerevisiae","pmids":["1944264"],"confidence":"High","gaps":["Mammalian ortholog not yet cloned","No complex membership determined","Biochemical activity unknown"]},{"year":2001,"claim":"Cloning of human VPS18 and the three other class C VPS genes confirmed evolutionary conservation from yeast to mammals and implicated the pathway in human lysosomal protein delivery.","evidence":"Molecular cloning and sequence/expression analysis","pmids":["11250079"],"confidence":"Medium","gaps":["No functional data in mammalian cells","Complex assembly not tested","No disease association"]},{"year":2005,"claim":"Zebrafish vps18 mutants revealed that VPS18 is required in vertebrates for endosomal-lysosomal trafficking and apical membrane biogenesis in hepatocytes, extending the role beyond generic vacuolar sorting to organ-specific vesicular pathways.","evidence":"Insertional mutagenesis screen with histology, EM, and live imaging in zebrafish","pmids":["16000385"],"confidence":"High","gaps":["Mechanism of apical membrane sorting unclear","HOPS versus CORVET contribution not distinguished"]},{"year":2006,"claim":"Demonstration that zebrafish vps18 mutation blocks melanosome maturation established VPS18-dependent trafficking as essential for lysosome-related organelle biogenesis.","evidence":"Insertional mutagenesis with histology and optokinetic response assay in zebrafish larvae","pmids":["16827750"],"confidence":"Medium","gaps":["Direct HOPS complex involvement inferred but not biochemically tested","Mammalian melanosome phenotype not examined"]},{"year":2008,"claim":"Two parallel studies showed VPS18 functions in phagosome-lysosome fusion (C. elegans) and autophagosome-lysosome fusion via interaction with UVRAG-Beclin1 and Rab7 activation (mammalian cells), establishing VPS18 as a convergence point for degradative vesicle fusion pathways.","evidence":"VPS-18 deletion mutant analysis with phagosome-lysosome fusion assays in C. elegans; Co-IP and Rab7 GTPase activity assays with autophagic flux measurement in mammalian cells","pmids":["18923146","18552835"],"confidence":"High","gaps":["Structural basis of Rab7 activation not resolved","Whether VPS18 directly contacts UVRAG or acts through other class C subunits unclear"]},{"year":2012,"claim":"Conditional knockout of Vps18 in mouse neurons revealed that VPS18 is essential for lysosomal homeostasis in the CNS: its loss blocks autophagy, endocytosis, and biosynthetic trafficking, causing neurodegeneration, β1 integrin accumulation, and Lysyl Oxidase-dependent dendrite defects.","evidence":"Nestin-Cre conditional KO mice with autophagy/endocytosis flux assays, Western blot, siRNA rescue; Purkinje cell-specific KO with Lox accumulation analysis","pmids":["22854957","22699122"],"confidence":"High","gaps":["Whether Lox is a direct VPS18 substrate or passively stabilized by lysosomal failure not distinguished","Relative HOPS versus CORVET contribution to dendritogenesis unknown"]},{"year":2014,"claim":"Identification of STX17 as the autophagosomal SNARE that directly recruits HOPS (including VPS18) resolved how autophagosomes are targeted for lysosomal fusion.","evidence":"Reciprocal Co-IP, mass spectrometry, siRNA knockdown with autophagic flux assays in mammalian cells","pmids":["24554770"],"confidence":"High","gaps":["Structural details of HOPS-STX17 interface lacking","Whether VPS18 directly contacts STX17 not determined"]},{"year":2017,"claim":"Biochemical demonstration that the VPS18 C-terminal RING domain directly heterodimerizes with VPS41 RING domain established the metazoan-specific mechanism by which VPS41 is recruited into the HOPS complex.","evidence":"Biochemical pulldown, Co-IP with endogenous HOPS, domain truncation/mutant analysis","pmids":["28931724"],"confidence":"High","gaps":["High-resolution structure of the RING-RING heterodimer not available","Whether this interaction is regulated remains unknown"]},{"year":2019,"claim":"Discovery that VPS18 (and VPS11) possess RING-dependent E3 ubiquitin ligase activity with PELP1 as a substrate added a catalytic signaling function to VPS18 beyond its tethering role, linking it to Wnt, ERα, and NF-κB pathway modulation.","evidence":"In vitro E3 ligase and ubiquitination assays, Co-IP, overexpression in Drosophila and mammalian cells with signaling readouts","pmids":["31015428"],"confidence":"High","gaps":["Full substrate repertoire unknown","Physiological relevance of E3 activity versus tethering function not genetically separated"]},{"year":2024,"claim":"VPS18 was shown to interact with PD-L1 in endosomal recycling compartments, promoting its glycosylation and surface stability; VPS18 depletion reduced PD-L1 levels and enhanced antitumor immunity, revealing an immuno-oncology axis through endosomal trafficking.","evidence":"Co-IP, CRISPR/siRNA knockdown, PD-L1 stability and glycosylation assays, in vivo tumor models","pmids":["39413192"],"confidence":"Medium","gaps":["Direct versus indirect mechanism of PD-L1 glycosylation enhancement not resolved","Whether VPS18 E3 ligase activity participates in PD-L1 regulation untested"]},{"year":2025,"claim":"Genome-wide CRISPR screen and validation identified VPS18 as essential for phagosomal membrane integrity during M. tuberculosis infection; separately, VPS18 loss elevated EGFR protein and ERK signaling in K-Ras-driven lung tumors, establishing a VPS18-EGFR-ERK degradative axis in tumorigenesis.","evidence":"CRISPR screen and KO with galectin damage assays in macrophages; conditional KO in LSL-K-Ras mice with dominant-negative EGFR rescue","pmids":["39888996","40615043"],"confidence":"High","gaps":["Whether VPS18 acts at phagosomal membranes independently of full HOPS complex not tested","Mechanism of phagosomal membrane stabilization unknown"]},{"year":2026,"claim":"Heterozygous VPS18 stop-gain mutations were identified as a cause of neutropenia in humans, with VPS18 deficiency destabilizing CORVET/HOPS, blocking vesicle dynamics and causing autophagosome accumulation and premature apoptosis in neutrophil progenitors — the first Mendelian disease link for VPS18.","evidence":"Patient mutation, CRISPR/Cas9 in Hoxb8 cells, iPSC differentiation, TEM, LC3/p62 Western blot, zebrafish model","pmids":["41526335"],"confidence":"High","gaps":["Genotype-phenotype spectrum beyond neutropenia not defined","Whether homozygous loss is embryonic lethal in humans unknown","Therapeutic rescue strategies not explored"]},{"year":null,"claim":"A high-resolution structure of the full human HOPS or CORVET complex with VPS18 is lacking, and the physiological balance between VPS18's tethering/scaffolding role and its E3 ubiquitin ligase activity has not been genetically dissected in vivo.","evidence":"","pmids":[],"confidence":"High","gaps":["No cryo-EM or crystal structure of human HOPS/CORVET complex","E3 ligase versus scaffolding function not genetically separated","Full substrate repertoire of VPS18 E3 activity undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016874","term_label":"ligase activity","supporting_discovery_ids":[11]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[11]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0,10,15]}],"localization":[{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[0,2,4,7,8]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[5,12,13]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[0,2,3]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,2,5,7,9,10,12,13]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[5,7,9,15]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[11,14]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[12,13]},{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[0,2,3]}],"complexes":["HOPS complex","CORVET complex"],"partners":["VPS41","VPS11","VPS16","VPS33A","STX17","PELP1","UVRAG"],"other_free_text":[]},"mechanistic_narrative":"VPS18 is a scaffold subunit shared by the HOPS and CORVET membrane-tethering complexes that orchestrates multiple vesicular trafficking routes to lysosomes, including endocytic, autophagic, phagocytic, and biosynthetic pathways. Its C-terminal RING domain forms a metazoan-specific heterodimer with the VPS41 RING domain to recruit VPS41 into the HOPS complex, and VPS18 also functions as an E3 ubiquitin ligase that modulates Wnt, ERα/PELP1, and NF-κB signaling [PMID:28931724, PMID:31015428]. Loss of VPS18 blocks lysosomal degradation of cargo such as EGFR and Lysyl Oxidase, leading to neurodegeneration, impaired dendritogenesis, and enhanced EGFR-ERK signaling in tumorigenesis, and it compromises phagosomal membrane integrity during Mycobacterium tuberculosis infection [PMID:22854957, PMID:40615043, PMID:39888996]. Heterozygous VPS18 loss-of-function mutations cause neutropenia through CORVET/HOPS complex instability, impaired vesicle dynamics, and premature neutrophil progenitor apoptosis [PMID:41526335]."},"prefetch_data":{"uniprot":{"accession":"Q9P253","full_name":"Vacuolar protein sorting-associated protein 18 homolog","aliases":[],"length_aa":973,"mass_kda":110.2,"function":"Plays a role in vesicle-mediated protein trafficking to lysosomal compartments including the endocytic membrane transport and autophagic pathways. Believed to act as a core component of the putative HOPS and CORVET endosomal tethering complexes which are proposed to be involved in the Rab5-to-Rab7 endosome conversion probably implicating MON1A/B, and via binding SNAREs and SNARE complexes to mediate tethering and docking events during SNARE-mediated membrane fusion. The HOPS complex is proposed to be recruited to Rab7 on the late endosomal membrane and to regulate late endocytic, phagocytic and autophagic traffic towards lysosomes. The CORVET complex is proposed to function as a Rab5 effector to mediate early endosome fusion probably in specific endosome subpopulations (PubMed:11382755, PubMed:23351085, PubMed:24554770, PubMed:25783203). Required for fusion of endosomes and autophagosomes with lysosomes (PubMed:25783203). Involved in dendrite development of Pukinje cells (By similarity)","subcellular_location":"Late endosome membrane; Lysosome membrane; Early endosome; Cytoplasmic vesicle, autophagosome; Cytoplasmic vesicle, clathrin-coated vesicle","url":"https://www.uniprot.org/uniprotkb/Q9P253/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/VPS18","classification":"Common Essential","n_dependent_lines":1126,"n_total_lines":1208,"dependency_fraction":0.9321192052980133},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000104142","cell_line_id":"CID001858","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"vesicles","grade":3}],"interactors":[{"gene":"VPS41","stoichiometry":10.0},{"gene":"VPS8","stoichiometry":10.0},{"gene":"VPS11","stoichiometry":10.0},{"gene":"VPS16","stoichiometry":10.0},{"gene":"TGFBRAP1","stoichiometry":10.0},{"gene":"VPS33A","stoichiometry":10.0},{"gene":"LSG1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID001858","total_profiled":1310},"omim":[{"mim_id":"620229","title":"FHF COMPLEX SUBUNIT HOOK-INTERACTING PROTEIN 1B; FHIP1B","url":"https://www.omim.org/entry/620229"},{"mim_id":"619389","title":"SPINOCEREBELLAR ATAXIA, AUTOSOMAL RECESSIVE 29; SCAR29","url":"https://www.omim.org/entry/619389"},{"mim_id":"617303","title":"MUCOPOLYSACCHARIDOSIS-PLUS SYNDROME; MPSPS","url":"https://www.omim.org/entry/617303"},{"mim_id":"616683","title":"LEUKODYSTROPHY, HYPOMYELINATING, 12; HLD12","url":"https://www.omim.org/entry/616683"},{"mim_id":"616303","title":"WD REPEAT-CONTAINING PROTEIN 91; WDR91","url":"https://www.omim.org/entry/616303"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/VPS18"},"hgnc":{"alias_symbol":["KIAA1475","PEP3"],"prev_symbol":[]},"alphafold":{"accession":"Q9P253","domains":[{"cath_id":"-","chopping":"92-224_227-260","consensus_level":"medium","plddt":86.5422,"start":92,"end":260},{"cath_id":"1.25.40","chopping":"553-806","consensus_level":"medium","plddt":73.305,"start":553,"end":806},{"cath_id":"-","chopping":"851-901_930-973","consensus_level":"medium","plddt":81.6057,"start":851,"end":973},{"cath_id":"1.25.40","chopping":"398-549","consensus_level":"medium","plddt":80.4134,"start":398,"end":549}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9P253","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9P253-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9P253-F1-predicted_aligned_error_v6.png","plddt_mean":78.81},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=VPS18","jax_strain_url":"https://www.jax.org/strain/search?query=VPS18"},"sequence":{"accession":"Q9P253","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9P253.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9P253/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9P253"}},"corpus_meta":[{"pmid":"16000385","id":"PMC_16000385","title":"A genetic screen in zebrafish identifies the mutants vps18, nf2 and foie gras as models of liver disease.","date":"2005","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/16000385","citation_count":150,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"1944264","id":"PMC_1944264","title":"Isolation and characterization of PEP3, a gene required for vacuolar biogenesis in Saccharomyces cerevisiae.","date":"1991","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/1944264","citation_count":64,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11250079","id":"PMC_11250079","title":"Molecular cloning and characterization of human VPS18, VPS 11, VPS16, and VPS33.","date":"2001","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/11250079","citation_count":59,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"18923146","id":"PMC_18923146","title":"Lysosome biogenesis mediated by vps-18 affects apoptotic 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vacuoles, with defects in delivery of vacuolar hydrolases (protease A, protease B, carboxypeptidase Y, alkaline phosphatase). The protein contains a C-terminal zinc finger (CX2CX13CX2C) domain.\",\n      \"method\": \"Genetic complementation, fractionation of PEP3::SUC2 fusion protein, fluorescence and electron microscopy of deletion mutants\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods (genetics, biochemical fractionation, EM), foundational paper with 64 citations\",\n      \"pmids\": [\"1944264\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Human VPS18, VPS11, VPS16, and VPS33 are homologs of yeast class C VPS genes; their molecular cloning and expression pattern were characterized, identifying them as candidate genes for lysosomal delivery pathways in humans.\",\n      \"method\": \"Molecular cloning, sequence analysis, expression pattern characterization\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — sequence/expression characterization, single study\",\n      \"pmids\": [\"11250079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Zebrafish vps18 mutation causes failure of endosomal-lysosomal trafficking in hepatocytes (large vesicle-filled cells), defects in bile canaliculi formation, and biliary paucity, demonstrating that Vps18 functions in vesicle trafficking to both the lysosome and the hepatocyte apical membrane.\",\n      \"method\": \"Zebrafish insertional mutagenesis screen, histology, fluorescence microscopy\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function with defined cellular phenotype in a vertebrate model, 150 citations\",\n      \"pmids\": [\"16000385\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Zebrafish vps18 mutant (retroviral insertion at exon 4 disrupting clathrin repeat and RING finger domains) shows drastic reduction in melanosome number in retinal pigmented epithelium and accumulation of immature melanosomes, establishing Vps18 as required for melanosome biogenesis.\",\n      \"method\": \"Zebrafish insertional mutant characterization, RT-PCR for splice variants, optokinetic response assay, electron microscopy\",\n      \"journal\": \"Pigment cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function with specific organelle phenotype, mechanistic domain analysis\",\n      \"pmids\": [\"16827750\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"C. elegans VPS-18 is expressed and functions in engulfing cells to mediate lysosome biogenesis; vps-18 deletion blocks phagosome-lysosome fusion and prevents degradation of internalized apoptotic cell corpses, placing VPS-18 in the endosomal/lysosomal degradation pathway downstream of engulfment.\",\n      \"method\": \"C. elegans deletion mutant analysis, fluorescence microscopy of phagosome-lysosome fusion, genetic epistasis\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods, clear pathway placement, 49 citations\",\n      \"pmids\": [\"18923146\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Human VPS18 (hVps18) is required for efficient production of infectious HIV-1 virions; depletion of hVps18 in human cells reduces infectious HIV-1 particle production, identified via yeast genetic screen for Gag plasma membrane targeting defects.\",\n      \"method\": \"Yeast genetic screen, siRNA knockdown in human cells, VLP release assay\",\n      \"journal\": \"Journal of virology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KD in human cells with specific functional readout, cross-validated in yeast\",\n      \"pmids\": [\"21450827\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Conditional knockout of Vps18 in neural cells (Nestin-Cre) blocks multiple vesicle transport pathways to the lysosome (autophagy, endocytosis, biosynthetic pathways), causes neurodegeneration, and leads to upregulation of β1 integrin due to lysosomal dysfunction; knockdown of β1 integrin partially rescues neuronal migration defects, placing Vps18 upstream of β1 integrin in a migration pathway.\",\n      \"method\": \"Conditional knockout mouse (Vps18-F/F; Nestin-Cre), immunofluorescence, western blot, epistasis by β1 integrin knockdown\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — in vivo KO with multiple pathway readouts and epistasis rescue experiment, 39 citations\",\n      \"pmids\": [\"22854957\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Vps18 deficiency in Purkinje cells blocks dendrite development by preventing lysosomal degradation of Lysyl Oxidase (Lox), causing Lox accumulation specifically in cerebellum but not cortex; lysosomal degradation of Lox is required for normal dendritogenesis.\",\n      \"method\": \"Conditional KO mouse, western blot, immunofluorescence for Lox accumulation in brain regions\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — specific substrate identified with regional specificity, but single study\",\n      \"pmids\": [\"22699122\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Human VPS18 recruits VPS41 to the HOPS complex via a direct RING domain–RING domain interaction, forming a stable heterodimer; the VPS18 RING domain is required to integrate VPS41 into the core complex. This mechanism is metazoan-specific as yeast Vps41 lacks a C-terminal zinc-finger motif.\",\n      \"method\": \"Biochemical pulldown, co-immunoprecipitation with endogenous HOPS, RING domain mutagenesis\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct in vitro binding, mutagenesis, and cell-based integration assay; 21 citations\",\n      \"pmids\": [\"28931724\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Vps11 and Vps18, common subunits of HOPS/CORVET complexes, function as E3 ubiquitin ligases; overexpression perturbs ubiquitination in signal transduction pathways including Wnt, ERα, and NFκB. Specifically, Vps11/18-mediated ubiquitination of scaffold protein PELP1 impairs ERα activation by c-Src.\",\n      \"method\": \"Overexpression, ubiquitination assays, co-immunoprecipitation, identification of PELP1 as substrate\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — E3 ligase activity and substrate identified, but mechanistic validation partly by overexpression\",\n      \"pmids\": [\"31015428\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"VPS11/VPS18 interact with PD-L1 in endosomes and promote PD-L1 recycling via the trans-Golgi network, increasing PD-L1 glycosylation and protein stability; VPS18 deficiency reduces PD-L1 surface levels and enhances antitumor immune response.\",\n      \"method\": \"Co-immunoprecipitation, VPS18 knockout, flow cytometry for PD-L1 surface expression, in vivo tumor models\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP and KO with defined molecular phenotype, single study\",\n      \"pmids\": [\"39413192\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"VPS18 colocalizes with Mycobacterium tuberculosis-containing phagosomes in macrophages and is required for phagosomal membrane integrity; VPS18-knockout macrophages show increased phagosomal membrane damage by Mtb and enhanced bacterial growth, independently of autophagy, identifying VPS18 as a host factor for phagosome repair.\",\n      \"method\": \"Genome-wide CRISPR screen, VPS18 KO macrophages, fluorescence microscopy for phagosomal membrane damage, bacterial growth assays\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — genome-wide CRISPR screen followed by KO validation with specific mechanistic readouts, multiple orthogonal methods\",\n      \"pmids\": [\"39888996\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Vps18 deficiency in lung epithelial cells elevates EGFR protein levels and activates ERK-MAPK signaling, accelerating lung tumorigenesis; expression of dominant-negative EGFR partially suppresses tumor promotion by Vps18 loss, defining a Vps18-EGFR-ERK axis where Vps18-mediated lysosomal degradation suppresses EGFR.\",\n      \"method\": \"Genetic ablation (LSL-K-Ras mouse model), western blot, dominant-negative EGFR epistasis rescue\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo KO with epistasis rescue, but single study\",\n      \"pmids\": [\"40615043\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"VPS18 deficiency in neutrophil progenitors causes CORVET/HOPS tethering complex instability, impairs vesicle dynamics with autophagosome accumulation (elevated LC3B-II and p62), and leads to premature apoptosis and maturation arrest; human iPSC-derived neutrophils lacking VPS18 show near-complete absence, and a patient with heterozygous stop-gain VPS18 mutation presents with neutropenia.\",\n      \"method\": \"CRISPR/Cas9 Hoxb8 cells, human iPSC differentiation, transmission electron microscopy, western blot, zebrafish vps18 mutant neutrophil counting\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal systems (murine cells, human iPSC, zebrafish, patient mutation), consistent phenotype\",\n      \"pmids\": [\"41526335\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"VPS18 is a central scaffold subunit of the CORVET and HOPS endosomal membrane-tethering complexes that recruits VPS41 via a RING–RING domain interaction, functions as an E3 ubiquitin ligase to regulate signaling (including ERα/PELP1 and Wnt/NFκB), and controls multiple vesicle transport pathways to lysosomes (endocytosis, autophagy, biosynthetic trafficking), thereby regulating lysosomal degradation of substrates such as EGFR and Lysyl Oxidase, phagosome-lysosome fusion (including phagosomal membrane repair in Mtb-infected macrophages), melanosome biogenesis, PD-L1 recycling and glycosylation, and neutrophil maturation.\"\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1991,\n      \"finding\": \"Yeast PEP3/VPS18 encodes a 107-kDa hydrophilic vacuolar peripheral membrane protein required for vacuolar biogenesis; loss-of-function results in accumulation of small vesicles instead of normal vacuoles and defects in delivery of vacuolar hydrolases (protease A, protease B, carboxypeptidase Y).\",\n      \"method\": \"Complementation cloning, deletion/disruption alleles, subcellular fractionation of PEP3::SUC2 fusion, fluorescence and electron microscopy\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (genetic complementation, fractionation, EM/fluorescence microscopy) in foundational study\",\n      \"pmids\": [\"1944264\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Human VPS18 (and VPS11, VPS16, VPS33) are homologs of yeast class C VPS genes; the four proteins are expressed in human tissues and are candidates for involvement in lysosomal protein delivery pathways conserved from yeast to mammals.\",\n      \"method\": \"Molecular cloning, sequence analysis, expression pattern determination\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — sequence/expression characterization; single lab, no functional reconstitution\",\n      \"pmids\": [\"11250079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Zebrafish vps18 mutation (class C VPS gene) causes hepatomegaly with vesicle-filled hepatocytes attributable to failure of endosomal-lysosomal trafficking, defects in bile canaliculi, and biliary paucity, demonstrating that vps18 is required for vesicle trafficking to both the lysosomal and hepatocyte apical membrane compartments.\",\n      \"method\": \"Insertional mutagenesis screen, histology, electron microscopy, live imaging in zebrafish embryos\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic loss-of-function with multiple defined cellular phenotypes in a vertebrate model organism\",\n      \"pmids\": [\"16000385\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Zebrafish vps18 mutant (retroviral insertion in exon 4 disrupting clathrin repeat and RING finger domains) shows severe reduction in melanosomes in retinal pigmented epithelium with accumulation of immature melanosomes, establishing that Vps18 is required for melanosome biogenesis via its role in the HOPS complex during vesicular traffic.\",\n      \"method\": \"Insertional mutagenesis, RT-PCR of splicing variants, histology, optokinetic response assay in zebrafish larvae\",\n      \"journal\": \"Pigment cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — defined loss-of-function phenotype with molecular characterization of truncation; single lab\",\n      \"pmids\": [\"16827750\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"C. elegans VPS-18 functions in engulfing cells to mediate lysosome biogenesis and phagosome-lysosome fusion; vps-18 deletion causes accumulation of undegraded apoptotic cell corpses due to failure of phagosome fusion with lysosomes.\",\n      \"method\": \"Deletion mutant analysis, fluorescence microscopy of endosomal/lysosomal markers, phagosome-lysosome fusion assay in C. elegans\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with defined cellular phenotype and direct fusion assay, multiple orthogonal readouts\",\n      \"pmids\": [\"18923146\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"The class C Vps complex (including Vps18) interacts with UVRAG-Beclin1 to stimulate Rab7 GTPase activity and promote autophagosome fusion with late endosomes/lysosomes as well as endosome-endosome fusion.\",\n      \"method\": \"Co-immunoprecipitation, Rab7 GTPase activity assay, autophagic flux assays in mammalian cells\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — biochemical activity assay plus Co-IP and functional flux assay; highly cited\",\n      \"pmids\": [\"18552835\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Human Vps18 and its yeast ortholog are required for efficient HIV-1 Gag-induced viruslike particle release and infectious virion production; depletion of hVps18 in human cells reduces infectious HIV-1 particle yield, placing Vps18-dependent trafficking in the HIV-1 budding pathway.\",\n      \"method\": \"Yeast genetic screen, siRNA knockdown in human cells, VLP release assay, viral infectivity measurement\",\n      \"journal\": \"Journal of virology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function in two systems with quantitative virion production readout; single lab\",\n      \"pmids\": [\"21450827\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Conditional knockout of Vps18 in neural cells (Nestin-Cre) causes neurodegeneration by blocking multiple vesicle transport pathways to the lysosome including autophagy, endocytosis, and biosynthetic pathways; Vps18 deficiency also causes β1 integrin upregulation due to lysosomal dysfunction, contributing to neuronal migration defects that are partially rescued by β1 integrin knockdown.\",\n      \"method\": \"Conditional KO mice (Vps18-F/F; Nestin-Cre), immunohistochemistry, Western blot, autophagy/endocytosis flux assays, siRNA rescue experiments\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — in vivo conditional KO with multiple mechanistic readouts and epistasis rescue experiment\",\n      \"pmids\": [\"22854957\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Vps18 deficiency in Purkinje cells blocks dendrite development by preventing lysosomal degradation of Lysyl Oxidase (Lox); Lox protein accumulates in Vps18-deficient cerebellum, linking lysosomal degradative function to dendritogenesis.\",\n      \"method\": \"Conditional KO mice, immunohistochemistry, Western blot for Lox in cerebellum vs. cortex\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — defined substrate accumulation in specific cell type with KO model; single lab\",\n      \"pmids\": [\"22699122\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"The HOPS complex (including VPS18) interacts with autophagosomal SNARE syntaxin 17 (STX17) to promote autophagosome-lysosome fusion; knockdown of HOPS subunits blocks autophagic flux and causes accumulation of STX17/LC3-positive autophagosomes.\",\n      \"method\": \"Immunoprecipitation, mass spectrometry, siRNA knockdown, autophagic flux assays in mammalian cells\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP identifying specific interaction, functional knockdown with defined phenotype; replicated\",\n      \"pmids\": [\"24554770\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Human VPS18 RING domain directly interacts with the RING domain of VPS41 to form a stable heterodimer required for VPS41 recruitment to the core HOPS complex; this RING-RING interaction is unique to metazoans as yeast Vps41 lacks a C-terminal zinc-finger motif.\",\n      \"method\": \"Biochemical pulldown, co-immunoprecipitation with endogenous HOPS, domain truncation/mutant analysis\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — direct biochemical demonstration of RING-RING heterodimer with functional integration into endogenous complex\",\n      \"pmids\": [\"28931724\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Vps11 and Vps18 (shared HOPS/CORVET subunits) function as E3 ubiquitin ligases; overexpression perturbs ubiquitination in signal transduction pathways including Wnt, ERα, and NFκB; specifically, Vps11/18-mediated ubiquitination of scaffold protein PELP1 impairs ERα activation by c-Src.\",\n      \"method\": \"E3 ligase activity assays, ubiquitination assays, Co-IP, overexpression in Drosophila and mammalian cells, signaling pathway readouts\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — enzymatic activity demonstrated with specific substrate identified, multiple pathways validated across organisms\",\n      \"pmids\": [\"31015428\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"VPS11/18 interact with PD-L1 in endosomal recycling and promote PD-L1 glycosylation and protein stability; VPS18 deficiency reduces PD-L1 surface levels and enhances antitumor immune response; VPS18 mediates trans-Golgi network recycling of PD-L1.\",\n      \"method\": \"Co-immunoprecipitation, siRNA/CRISPR knockdown, PD-L1 stability and glycosylation assays, in vivo tumor models, pharmacological inhibition\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP interaction plus functional KO and pharmacological evidence; single lab\",\n      \"pmids\": [\"39413192\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"VPS18 is required for phagosomal membrane integrity in Mycobacterium tuberculosis-infected macrophages; VPS18-knockout macrophages show increased phagosomal damage without impaired autophagy, Mtb grows more robustly, and antibiotic efficacy (pyrazinamide) is reduced; VPS18 colocalizes with Mtb-containing phagosomes shortly after infection.\",\n      \"method\": \"Genome-wide CRISPR screen, CRISPR KO, galectin-based phagosomal damage assay, live-cell imaging, antibiotic efficacy assay\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genome-wide unbiased screen plus validated KO with multiple mechanistic readouts\",\n      \"pmids\": [\"39888996\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Vps18 deficiency in LSL-K-Ras lung tumors elevates EGFR protein levels and activates ERK-MAPK signaling; expression of dominant-negative EGFR partially suppresses the tumor-promoting effects of Vps18 loss, establishing a Vps18-EGFR-ERK axis in lung tumorigenesis via lysosomal degradation of EGFR.\",\n      \"method\": \"Conditional KO in LSL-K-Ras mice, Western blot, EGFR dominant-negative rescue, ERK-MAPK pathway analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo genetic model with epistasis rescue; single lab, single paper\",\n      \"pmids\": [\"40615043\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"VPS18 deficiency in neutrophil progenitors causes CORVET/HOPS tethering complex instability, impaired vesicle dynamics with autophagosome accumulation (increased LC3B-II and p62), and premature apoptosis, resulting in a neutrophil maturation defect; heterozygous VPS18 stop-gain mutations in a human patient and in iPSC/zebrafish models cause neutropenia.\",\n      \"method\": \"CRISPR/Cas9 Hoxb8 cells, iPSC differentiation, TEM, LC3/p62 Western blot, zebrafish model, patient mutation characterization\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal models (cell line, iPSC, zebrafish, patient) with defined mechanistic readouts\",\n      \"pmids\": [\"41526335\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"VPS18 is a central scaffold subunit shared by the HOPS and CORVET membrane-tethering complexes that regulates multiple vesicular trafficking pathways to lysosomes/vacuoles—including endocytosis, autophagy, and biosynthetic routes—by facilitating SNARE-mediated membrane fusion; its C-terminal RING domain directly recruits VPS41 into HOPS, it functions as an E3 ubiquitin ligase to fine-tune signaling (e.g., ERα/PELP1, Wnt, NFκB), it promotes lysosomal degradation of substrates such as EGFR and Lysyl Oxidase to regulate cell proliferation and dendritogenesis, it maintains phagosomal membrane integrity against Mycobacterium tuberculosis, and it controls PD-L1 glycosylation and recycling through endosomal trafficking.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"VPS18 is a core scaffold subunit of the CORVET and HOPS endosomal membrane-tethering complexes that controls multiple vesicle transport pathways converging on the lysosome, including endocytosis, autophagy, and biosynthetic trafficking. VPS18 recruits VPS41 into the HOPS complex via a metazoan-specific RING–RING domain heterodimer interaction and also possesses E3 ubiquitin ligase activity through which it ubiquitinates substrates such as PELP1 to modulate ERα and Wnt/NF-κB signaling [PMID:28931724, PMID:31015428]. Loss of VPS18 impairs lysosomal degradation of cargo including EGFR and Lysyl Oxidase, disrupts phagosome–lysosome fusion and phagosomal membrane repair, blocks melanosome biogenesis, causes neurodegeneration, and accelerates lung tumorigenesis through EGFR–ERK hyperactivation [PMID:22854957, PMID:22699122, PMID:16827750, PMID:39888996, PMID:40615043]. VPS18 deficiency destabilizes the CORVET/HOPS complexes in neutrophil progenitors leading to autophagosome accumulation, maturation arrest, and neutropenia, and a heterozygous stop-gain VPS18 mutation has been identified in a patient with neutropenia [PMID:41526335].\",\n  \"teleology\": [\n    {\n      \"year\": 1991,\n      \"claim\": \"Identification of yeast Pep3/Vps18 as a peripheral membrane protein required for vacuolar biogenesis established it as a central player in vesicle-mediated delivery to the vacuole/lysosome, with a C-terminal zinc finger domain essential for function.\",\n      \"evidence\": \"Genetic complementation, biochemical fractionation, and electron microscopy in yeast\",\n      \"pmids\": [\"1944264\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No binding partners identified\", \"Zinc finger function not tested by mutagenesis\", \"No mammalian homolog characterized\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Cloning of human VPS18 and its class C complex partners (VPS11, VPS16, VPS33) demonstrated conservation of the lysosomal delivery machinery from yeast to humans.\",\n      \"evidence\": \"Molecular cloning and expression profiling of human homologs\",\n      \"pmids\": [\"11250079\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional validation of human VPS18\", \"Complex assembly not tested biochemically\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Zebrafish vps18 mutants revealed that Vps18 is required not only for lysosomal trafficking but also for apical membrane delivery in polarized cells, broadening its role beyond simple vacuolar sorting.\",\n      \"evidence\": \"Zebrafish insertional mutagenesis with histological and fluorescence microscopy analysis of hepatocytes\",\n      \"pmids\": [\"16000385\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism of apical trafficking role unclear\", \"No direct biochemical characterization of mutant protein\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Demonstration that vps18 loss disrupts melanosome biogenesis in zebrafish extended VPS18 function to lysosome-related organelle formation, implicating both the clathrin-repeat and RING finger domains.\",\n      \"evidence\": \"Zebrafish mutant electron microscopy showing immature melanosome accumulation, domain mapping by RT-PCR\",\n      \"pmids\": [\"16827750\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific domain requirements not tested by point mutation\", \"Mammalian melanosome phenotype not confirmed\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"C. elegans VPS-18 was placed specifically at the phagosome–lysosome fusion step in engulfing cells, establishing that VPS18 functions downstream of corpse engulfment to promote degradation of phagocytosed material.\",\n      \"evidence\": \"C. elegans deletion mutant with fluorescence imaging of phagosome–lysosome fusion and genetic epistasis\",\n      \"pmids\": [\"18923146\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct membrane tethering function not biochemically demonstrated\", \"HOPS/CORVET complex composition in worm not resolved\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Conditional knockout of Vps18 in mouse neural cells showed it is required for all three major vesicle transport pathways to the lysosome (endocytic, autophagic, biosynthetic) and revealed that lysosomal dysfunction causes β1-integrin accumulation affecting neuronal migration, while in Purkinje cells Vps18 loss causes Lysyl Oxidase accumulation that impairs dendritogenesis.\",\n      \"evidence\": \"Nestin-Cre conditional KO mice with immunofluorescence, western blot, and epistasis by β1-integrin or Lox pathway analysis\",\n      \"pmids\": [\"22854957\", \"22699122\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Vps18 directly sorts β1-integrin or Lox for degradation vs. general lysosome failure is unclear\", \"Purkinje cell-specific requirement not mechanistically explained\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"The mechanism by which VPS18 organizes the HOPS complex was resolved: its RING domain directly binds the RING domain of VPS41 to form a heterodimer that integrates VPS41 into the complex, a metazoan-specific interaction absent in yeast.\",\n      \"evidence\": \"Biochemical pulldown, co-immunoprecipitation of endogenous HOPS, RING domain mutagenesis in human cells\",\n      \"pmids\": [\"28931724\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the RING–RING dimer not resolved at atomic level\", \"Whether this interaction is regulated remains unknown\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"VPS18 was shown to possess E3 ubiquitin ligase activity independent of its tethering role, ubiquitinating PELP1 to impair ERα activation by c-Src and perturbing Wnt and NF-κB signaling, revealing a dual function as both tethering complex scaffold and signaling modulator.\",\n      \"evidence\": \"Overexpression and ubiquitination assays, co-immunoprecipitation identifying PELP1 as substrate\",\n      \"pmids\": [\"31015428\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"E3 ligase activity demonstrated primarily by overexpression; endogenous-level validation needed\", \"Full spectrum of ubiquitination substrates unknown\", \"Relationship between E3 ligase and tethering functions not dissected\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"VPS18 was found to interact with PD-L1 in endosomes and promote its recycling via the trans-Golgi network, controlling PD-L1 glycosylation, surface stability, and thereby tumor immune evasion, linking endosomal tethering to immune checkpoint regulation.\",\n      \"evidence\": \"Co-immunoprecipitation, VPS18 knockout, flow cytometry, and in vivo tumor models\",\n      \"pmids\": [\"39413192\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether VPS18 directly binds PD-L1 or acts through the HOPS complex is not resolved\", \"Mechanism of recycling vs. degradation routing unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"VPS18 was identified as a host factor for phagosomal membrane repair in Mycobacterium tuberculosis–infected macrophages; its loss increases phagosomal membrane damage and bacterial growth independently of autophagy, distinguishing membrane repair from degradative functions.\",\n      \"evidence\": \"Genome-wide CRISPR screen, VPS18 KO macrophages, fluorescence microscopy for membrane damage, bacterial growth assays\",\n      \"pmids\": [\"39888996\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism of membrane repair by VPS18/HOPS not defined\", \"Whether CORVET or HOPS mediates this function is unresolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Loss of Vps18 in lung epithelium elevates EGFR protein and activates ERK–MAPK signaling to accelerate Kras-driven lung tumorigenesis, establishing VPS18-mediated lysosomal degradation of EGFR as a tumor-suppressive mechanism.\",\n      \"evidence\": \"Genetic ablation in LSL-K-Ras mouse model with dominant-negative EGFR epistasis rescue\",\n      \"pmids\": [\"40615043\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether EGFR is a direct cargo sorted by VPS18-containing complexes not shown\", \"Applicability to human lung cancer not validated\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"VPS18 was shown to be essential for neutrophil maturation by maintaining CORVET/HOPS complex stability and proper vesicle dynamics; its loss causes autophagosome accumulation and premature apoptosis, and a patient heterozygous stop-gain VPS18 mutation causes neutropenia.\",\n      \"evidence\": \"CRISPR/Cas9 in murine Hoxb8 progenitors, human iPSC-derived neutrophils, zebrafish, and patient genotyping\",\n      \"pmids\": [\"41526335\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Single patient—genetic causality not formally proven by rescue\", \"Why neutrophils are selectively vulnerable to VPS18 haploinsufficiency is unexplained\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include: (1) the structural basis for VPS18 scaffold organization within both CORVET and HOPS, (2) how its E3 ligase activity is coordinated with or independent of its tethering function, (3) the full repertoire of ubiquitination substrates at endogenous expression levels, and (4) whether VPS18 mutations cause a defined human Mendelian disorder beyond isolated neutropenia.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No atomic-resolution structure of VPS18 in complex\", \"E3 ligase substrates not systematically catalogued\", \"Genotype–phenotype relationship in humans not established beyond a single patient\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016874\", \"supporting_discovery_ids\": [9]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [9]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 8, 13]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [4, 10, 11]},\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [0, 4, 6]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 2, 4, 6, 8, 10]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [6, 13]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [0, 3, 6]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [9, 12]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [10, 11]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [13]}\n    ],\n    \"complexes\": [\n      \"HOPS complex\",\n      \"CORVET complex\"\n    ],\n    \"partners\": [\n      \"VPS41\",\n      \"VPS11\",\n      \"VPS16\",\n      \"VPS33\",\n      \"PELP1\",\n      \"PD-L1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"mechanistic_narrative\": \"VPS18 is a scaffold subunit shared by the HOPS and CORVET membrane-tethering complexes that orchestrates multiple vesicular trafficking routes to lysosomes, including endocytic, autophagic, phagocytic, and biosynthetic pathways. Its C-terminal RING domain forms a metazoan-specific heterodimer with the VPS41 RING domain to recruit VPS41 into the HOPS complex, and VPS18 also functions as an E3 ubiquitin ligase that modulates Wnt, ERα/PELP1, and NF-κB signaling [PMID:28931724, PMID:31015428]. Loss of VPS18 blocks lysosomal degradation of cargo such as EGFR and Lysyl Oxidase, leading to neurodegeneration, impaired dendritogenesis, and enhanced EGFR-ERK signaling in tumorigenesis, and it compromises phagosomal membrane integrity during Mycobacterium tuberculosis infection [PMID:22854957, PMID:40615043, PMID:39888996]. Heterozygous VPS18 loss-of-function mutations cause neutropenia through CORVET/HOPS complex instability, impaired vesicle dynamics, and premature neutrophil progenitor apoptosis [PMID:41526335].\",\n  \"teleology\": [\n    {\n      \"year\": 1991,\n      \"claim\": \"Identification of PEP3/VPS18 as a gene required for vacuolar biogenesis in yeast established that the protein is essential for vesicular delivery of hydrolases to the vacuole, founding the class C VPS pathway.\",\n      \"evidence\": \"Complementation cloning, gene disruption, subcellular fractionation, and electron microscopy in S. cerevisiae\",\n      \"pmids\": [\"1944264\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mammalian ortholog not yet cloned\", \"No complex membership determined\", \"Biochemical activity unknown\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Cloning of human VPS18 and the three other class C VPS genes confirmed evolutionary conservation from yeast to mammals and implicated the pathway in human lysosomal protein delivery.\",\n      \"evidence\": \"Molecular cloning and sequence/expression analysis\",\n      \"pmids\": [\"11250079\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional data in mammalian cells\", \"Complex assembly not tested\", \"No disease association\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Zebrafish vps18 mutants revealed that VPS18 is required in vertebrates for endosomal-lysosomal trafficking and apical membrane biogenesis in hepatocytes, extending the role beyond generic vacuolar sorting to organ-specific vesicular pathways.\",\n      \"evidence\": \"Insertional mutagenesis screen with histology, EM, and live imaging in zebrafish\",\n      \"pmids\": [\"16000385\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of apical membrane sorting unclear\", \"HOPS versus CORVET contribution not distinguished\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Demonstration that zebrafish vps18 mutation blocks melanosome maturation established VPS18-dependent trafficking as essential for lysosome-related organelle biogenesis.\",\n      \"evidence\": \"Insertional mutagenesis with histology and optokinetic response assay in zebrafish larvae\",\n      \"pmids\": [\"16827750\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct HOPS complex involvement inferred but not biochemically tested\", \"Mammalian melanosome phenotype not examined\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Two parallel studies showed VPS18 functions in phagosome-lysosome fusion (C. elegans) and autophagosome-lysosome fusion via interaction with UVRAG-Beclin1 and Rab7 activation (mammalian cells), establishing VPS18 as a convergence point for degradative vesicle fusion pathways.\",\n      \"evidence\": \"VPS-18 deletion mutant analysis with phagosome-lysosome fusion assays in C. elegans; Co-IP and Rab7 GTPase activity assays with autophagic flux measurement in mammalian cells\",\n      \"pmids\": [\"18923146\", \"18552835\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of Rab7 activation not resolved\", \"Whether VPS18 directly contacts UVRAG or acts through other class C subunits unclear\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Conditional knockout of Vps18 in mouse neurons revealed that VPS18 is essential for lysosomal homeostasis in the CNS: its loss blocks autophagy, endocytosis, and biosynthetic trafficking, causing neurodegeneration, β1 integrin accumulation, and Lysyl Oxidase-dependent dendrite defects.\",\n      \"evidence\": \"Nestin-Cre conditional KO mice with autophagy/endocytosis flux assays, Western blot, siRNA rescue; Purkinje cell-specific KO with Lox accumulation analysis\",\n      \"pmids\": [\"22854957\", \"22699122\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Lox is a direct VPS18 substrate or passively stabilized by lysosomal failure not distinguished\", \"Relative HOPS versus CORVET contribution to dendritogenesis unknown\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identification of STX17 as the autophagosomal SNARE that directly recruits HOPS (including VPS18) resolved how autophagosomes are targeted for lysosomal fusion.\",\n      \"evidence\": \"Reciprocal Co-IP, mass spectrometry, siRNA knockdown with autophagic flux assays in mammalian cells\",\n      \"pmids\": [\"24554770\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural details of HOPS-STX17 interface lacking\", \"Whether VPS18 directly contacts STX17 not determined\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Biochemical demonstration that the VPS18 C-terminal RING domain directly heterodimerizes with VPS41 RING domain established the metazoan-specific mechanism by which VPS41 is recruited into the HOPS complex.\",\n      \"evidence\": \"Biochemical pulldown, Co-IP with endogenous HOPS, domain truncation/mutant analysis\",\n      \"pmids\": [\"28931724\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"High-resolution structure of the RING-RING heterodimer not available\", \"Whether this interaction is regulated remains unknown\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Discovery that VPS18 (and VPS11) possess RING-dependent E3 ubiquitin ligase activity with PELP1 as a substrate added a catalytic signaling function to VPS18 beyond its tethering role, linking it to Wnt, ERα, and NF-κB pathway modulation.\",\n      \"evidence\": \"In vitro E3 ligase and ubiquitination assays, Co-IP, overexpression in Drosophila and mammalian cells with signaling readouts\",\n      \"pmids\": [\"31015428\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full substrate repertoire unknown\", \"Physiological relevance of E3 activity versus tethering function not genetically separated\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"VPS18 was shown to interact with PD-L1 in endosomal recycling compartments, promoting its glycosylation and surface stability; VPS18 depletion reduced PD-L1 levels and enhanced antitumor immunity, revealing an immuno-oncology axis through endosomal trafficking.\",\n      \"evidence\": \"Co-IP, CRISPR/siRNA knockdown, PD-L1 stability and glycosylation assays, in vivo tumor models\",\n      \"pmids\": [\"39413192\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct versus indirect mechanism of PD-L1 glycosylation enhancement not resolved\", \"Whether VPS18 E3 ligase activity participates in PD-L1 regulation untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Genome-wide CRISPR screen and validation identified VPS18 as essential for phagosomal membrane integrity during M. tuberculosis infection; separately, VPS18 loss elevated EGFR protein and ERK signaling in K-Ras-driven lung tumors, establishing a VPS18-EGFR-ERK degradative axis in tumorigenesis.\",\n      \"evidence\": \"CRISPR screen and KO with galectin damage assays in macrophages; conditional KO in LSL-K-Ras mice with dominant-negative EGFR rescue\",\n      \"pmids\": [\"39888996\", \"40615043\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether VPS18 acts at phagosomal membranes independently of full HOPS complex not tested\", \"Mechanism of phagosomal membrane stabilization unknown\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Heterozygous VPS18 stop-gain mutations were identified as a cause of neutropenia in humans, with VPS18 deficiency destabilizing CORVET/HOPS, blocking vesicle dynamics and causing autophagosome accumulation and premature apoptosis in neutrophil progenitors — the first Mendelian disease link for VPS18.\",\n      \"evidence\": \"Patient mutation, CRISPR/Cas9 in Hoxb8 cells, iPSC differentiation, TEM, LC3/p62 Western blot, zebrafish model\",\n      \"pmids\": [\"41526335\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Genotype-phenotype spectrum beyond neutropenia not defined\", \"Whether homozygous loss is embryonic lethal in humans unknown\", \"Therapeutic rescue strategies not explored\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"A high-resolution structure of the full human HOPS or CORVET complex with VPS18 is lacking, and the physiological balance between VPS18's tethering/scaffolding role and its E3 ubiquitin ligase activity has not been genetically dissected in vivo.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No cryo-EM or crystal structure of human HOPS/CORVET complex\", \"E3 ligase versus scaffolding function not genetically separated\", \"Full substrate repertoire of VPS18 E3 activity undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016874\", \"supporting_discovery_ids\": [11]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [11]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 10, 15]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [0, 2, 4, 7, 8]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [5, 12, 13]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [0, 2, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 2, 5, 7, 9, 10, 12, 13]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [5, 7, 9, 15]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [11, 14]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [12, 13]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [0, 2, 3]}\n    ],\n    \"complexes\": [\n      \"HOPS complex\",\n      \"CORVET complex\"\n    ],\n    \"partners\": [\n      \"VPS41\",\n      \"VPS11\",\n      \"VPS16\",\n      \"VPS33A\",\n      \"STX17\",\n      \"PELP1\",\n      \"UVRAG\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}