{"gene":"PDCL3","run_date":"2026-06-10T05:19:53","timeline":{"discoveries":[{"year":2013,"finding":"PDCL3 was identified as a chaperone protein that binds to the juxtamembrane domain of VEGFR-2, inhibits its ubiquitination and proteasomal degradation, and thereby controls VEGFR-2 surface abundance. PDCL3 also increases VEGF-induced tyrosine phosphorylation of VEGFR-2 and is required for VEGFR-2-dependent endothelial capillary tube formation and proliferation.","method":"Yeast two-hybrid screen, co-immunoprecipitation, siRNA knockdown, VEGFR-2 ubiquitination assay, endothelial tube formation and proliferation assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal binding assay (yeast two-hybrid + Co-IP), functional ubiquitination assay, and multiple cellular phenotypic readouts in a single focused mechanistic study","pmids":["23792958"],"is_preprint":false},{"year":2015,"finding":"PDCL3 undergoes N-terminal methionine acetylation, and this modification is required for its hypoxia-induced upregulation and for its interaction with VEGFR-2. A mutant PDCL3 unable to undergo N-terminal methionine acetylation is refractory to hypoxia. PDCL3 also protects VEGFR-2 from misfolding and aggregation, and is required for angiogenesis in zebrafish and mouse models.","method":"Mass spectrometry (N-terminal acetylation identification), site-directed mutagenesis of acetylation site, siRNA knockdown, VEGFR-2 protein aggregation assay, in vivo zebrafish and mouse angiogenesis models","journal":"Angiogenesis","confidence":"High","confidence_rationale":"Tier 2 / Moderate — PTM identified by MS, validated by mutagenesis, functional consequences tested in vitro and in vivo across two model organisms","pmids":["26059764"],"is_preprint":false},{"year":2009,"finding":"Human PDCL3 (ortholog of yeast PLP2) acts as an inhibitory regulator of CCT (chaperonin-containing TCP-1)-mediated folding of beta-actin in vitro and in vivo. This inhibitory activity is conferred by PDCL3's acidic C-terminal extension, since replacing it with the C-terminal extension of yeast PLP2 relieves the inhibition. In contrast, yeast PLP2 is a stimulatory co-factor for CCT-mediated actin folding, forming a ternary PLP2-CCT-actin complex.","method":"In vitro CCT-actin folding assay using rabbit reticulocyte lysate translation system, C-terminal domain swap mutagenesis, in vitro reconstitution with purified yeast components","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution of folding assay combined with mutagenesis (domain swap) in a single rigorous study","pmids":["19501098"],"is_preprint":false},{"year":2020,"finding":"Compound heterozygous loss-of-function variants in PDCL3 (c.[143_144del];[380G>A]) were identified in patients with megacystis-microcolon-intestinal-hypoperistalsis syndrome (MMIHS). cDNA analysis showed complete absence of PDCL3 expression in affected individuals due to nonsense-mediated mRNA decay, implicating PDCL3's actin-folding chaperone function in smooth muscle contractility.","method":"Exome sequencing, cDNA expression analysis (nonsense-mediated decay confirmation)","journal":"Clinical genetics","confidence":"Medium","confidence_rationale":"Tier 3 / Weak — genetic identification of loss-of-function variants with mRNA decay confirmation, single study, no direct in vitro functional rescue experiment","pmids":["32621347"],"is_preprint":false},{"year":2025,"finding":"In glioma-associated mesenchymal stem cells (GA-MSCs), PDCL3 upregulation promotes expression of VEGFR-2 and pericyte markers, facilitating transformation of GA-MSCs into pericytes and enhancing vasculogenic mimicry when co-cultured with HUVECs.","method":"siRNA knockdown of PDCL3, overexpression experiments, co-culture vasculogenic mimicry assay, Western blot for VEGFR-2 and pericyte markers","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 3 / Weak — single lab, loss-of-function and overexpression with cellular phenotype readouts but limited mechanistic dissection beyond VEGFR-2 axis","pmids":["40469100"],"is_preprint":false}],"current_model":"PDCL3 is a chaperone protein that (1) folds actin in a CCT-dependent manner but acts as an inhibitor (not activator) of CCT-mediated beta-actin folding via its acidic C-terminal extension, and (2) stabilizes VEGFR-2 by binding its juxtamembrane domain, blocking ubiquitination and degradation, and protecting it from misfolding—a function regulated by hypoxia-induced N-terminal methionine acetylation—thereby promoting angiogenesis; loss-of-function mutations in PDCL3 cause defective smooth muscle contractility manifesting as MMIHS."},"narrative":{"mechanistic_narrative":"PDCL3 is a phosducin-like chaperone protein that operates in two distinct cellular contexts: cytoskeletal protein folding and receptor tyrosine kinase stabilization [PMID:23792958, PMID:19501098]. As the human ortholog of yeast PLP2, PDCL3 engages the CCT (chaperonin-containing TCP-1) chaperonin to regulate beta-actin folding, but unlike its stimulatory yeast counterpart it acts as an inhibitor of CCT-mediated actin folding, an activity conferred by its acidic C-terminal extension [PMID:19501098]. In endothelial cells, PDCL3 binds the juxtamembrane domain of VEGFR-2, blocks its ubiquitination and proteasomal degradation, protects the receptor from misfolding and aggregation, and thereby raises VEGFR-2 surface abundance and VEGF-induced tyrosine phosphorylation to drive endothelial proliferation, capillary tube formation, and angiogenesis in zebrafish and mouse models [PMID:23792958, PMID:26059764]. This VEGFR-2-stabilizing function is gated by N-terminal methionine acetylation of PDCL3, a modification required for its hypoxia-induced upregulation and its interaction with VEGFR-2 [PMID:26059764]. The same VEGFR-2 axis is co-opted in glioma-associated mesenchymal stem cells, where PDCL3 upregulation promotes their conversion to pericytes and enhances vasculogenic mimicry [PMID:40469100]. Compound heterozygous loss-of-function variants in PDCL3 cause megacystis-microcolon-intestinal-hypoperistalsis syndrome (MMIHS), linking its actin-folding chaperone role to smooth muscle contractility [PMID:32621347].","teleology":[{"year":2009,"claim":"Established whether human PDCL3 modulates CCT-dependent cytoskeletal protein folding, and whether it shares the function of its yeast ortholog, defining its core chaperone identity.","evidence":"In vitro CCT-actin folding assay in reticulocyte lysate with C-terminal domain-swap mutagenesis and reconstitution using purified yeast components","pmids":["19501098"],"confidence":"High","gaps":["Mechanism by which the acidic C-terminal extension inhibits CCT not structurally resolved","Cellular consequences of actin-folding inhibition in specific tissues not defined","Does not address PDCL3's role outside the cytoskeleton"]},{"year":2013,"claim":"Identified PDCL3 as a direct binding partner and stabilizer of VEGFR-2, answering how the receptor's surface abundance is controlled and extending PDCL3's chaperone role to receptor tyrosine kinase signaling.","evidence":"Yeast two-hybrid screen, co-immunoprecipitation, siRNA knockdown, VEGFR-2 ubiquitination assay, and endothelial tube formation/proliferation assays","pmids":["23792958"],"confidence":"High","gaps":["Structural basis of juxtamembrane-domain binding not resolved","Whether VEGFR-2 stabilization requires the CCT machinery not addressed","Identity of the ubiquitin ligase blocked by PDCL3 not defined"]},{"year":2015,"claim":"Defined the upstream regulatory input controlling PDCL3's VEGFR-2 function, showing that N-terminal methionine acetylation couples hypoxia to receptor stabilization and angiogenesis in vivo.","evidence":"Mass spectrometry PTM identification, acetylation-site mutagenesis, protein aggregation assay, and zebrafish and mouse angiogenesis models","pmids":["26059764"],"confidence":"High","gaps":["Enzyme(s) responsible for hypoxia-regulated N-terminal acetylation not identified","How acetylation mechanistically promotes VEGFR-2 binding unclear","Relationship between the actin-folding and VEGFR-2 functions not integrated"]},{"year":2020,"claim":"Linked PDCL3 to human disease, showing that biallelic loss-of-function causes MMIHS and implicating its chaperone function in smooth muscle contractility.","evidence":"Exome sequencing and cDNA analysis confirming nonsense-mediated decay in affected individuals","pmids":["32621347"],"confidence":"Medium","gaps":["No direct in vitro functional rescue experiment performed","Whether the actin-folding or another function underlies the smooth muscle defect not established","Single study without independent patient cohort"]},{"year":2025,"claim":"Extended the PDCL3-VEGFR-2 axis to a tumor microenvironment context, showing PDCL3 drives mesenchymal-to-pericyte transformation and vasculogenic mimicry.","evidence":"siRNA knockdown and overexpression in glioma-associated mesenchymal stem cells with co-culture vasculogenic mimicry assays and Western blot","pmids":["40469100"],"confidence":"Medium","gaps":["Mechanistic dissection limited to the VEGFR-2 readout","Single lab without in vivo tumor confirmation","Whether PDCL3 acetylation/hypoxia regulation operates in this context untested"]},{"year":null,"claim":"How PDCL3's two activities — CCT-coupled actin folding and VEGFR-2 stabilization — are mechanistically and structurally related, and which underlies each disease phenotype, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of PDCL3 in either complex","No unified mechanism connecting actin and VEGFR-2 functions","Acetyltransferase and deubiquitination/ligase partners unidentified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0044183","term_label":"protein folding chaperone","supporting_discovery_ids":[0,1,2]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,2]}],"localization":[],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,1]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[2]}],"complexes":["CCT/TRiC"],"partners":["KDR","CCT/TCP-1","ACTB"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9H2J4","full_name":"Phosducin-like protein 3","aliases":["HTPHLP","PhPL3","Viral IAP-associated factor 1","VIAF-1"],"length_aa":239,"mass_kda":27.6,"function":"Acts as a chaperone for the angiogenic VEGF receptor KDR/VEGFR2, increasing its abundance by inhibiting its ubiquitination and degradation (PubMed:23792958, PubMed:26059764). Inhibits the folding activity of the chaperonin-containing T-complex (CCT) which leads to inhibition of cytoskeletal actin folding (PubMed:17429077). Acts as a chaperone during heat shock alongside HSP90 and HSP40/70 chaperone complexes (By similarity). Modulates the activation of caspases during apoptosis (PubMed:15371430)","subcellular_location":"Cytoplasm; Cytoplasm, perinuclear region; Endoplasmic reticulum","url":"https://www.uniprot.org/uniprotkb/Q9H2J4/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PDCL3","classification":"Not Classified","n_dependent_lines":144,"n_total_lines":1208,"dependency_fraction":0.11920529801324503},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000115539","cell_line_id":"CID001884","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"nucleoplasm","grade":1}],"interactors":[{"gene":"ACTR2","stoichiometry":4.0},{"gene":"ACTB","stoichiometry":0.2},{"gene":"ACTG1","stoichiometry":0.2},{"gene":"CCT2","stoichiometry":0.2},{"gene":"CCT3","stoichiometry":0.2},{"gene":"CCT4","stoichiometry":0.2},{"gene":"CCT5","stoichiometry":0.2},{"gene":"CCT6A","stoichiometry":0.2},{"gene":"CCT7","stoichiometry":0.2},{"gene":"CCT8","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID001884","total_profiled":1310},"omim":[{"mim_id":"611678","title":"PHOSDUCIN-LIKE 3; PDCL3","url":"https://www.omim.org/entry/611678"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Cytosol","reliability":"Enhanced"},{"location":"Nucleoplasm","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/PDCL3"},"hgnc":{"alias_symbol":["VIAF1"],"prev_symbol":[]},"alphafold":{"accession":"Q9H2J4","domains":[{"cath_id":"3.40.30.10","chopping":"96-202","consensus_level":"high","plddt":91.8564,"start":96,"end":202}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H2J4","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H2J4-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H2J4-F1-predicted_aligned_error_v6.png","plddt_mean":79.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PDCL3","jax_strain_url":"https://www.jax.org/strain/search?query=PDCL3"},"sequence":{"accession":"Q9H2J4","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9H2J4.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9H2J4/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H2J4"}},"corpus_meta":[{"pmid":"26830138","id":"PMC_26830138","title":"Family-based association analyses of imputed genotypes reveal genome-wide significant association of Alzheimer's disease with OSBPL6, PTPRG, and PDCL3.","date":"2016","source":"Molecular psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/26830138","citation_count":78,"is_preprint":false},{"pmid":"26059764","id":"PMC_26059764","title":"Hypoxia-induced expression of phosducin-like 3 regulates expression of VEGFR-2 and promotes angiogenesis.","date":"2015","source":"Angiogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/26059764","citation_count":43,"is_preprint":false},{"pmid":"19501098","id":"PMC_19501098","title":"Yeast phosducin-like protein 2 acts as a stimulatory co-factor for the folding of actin by the chaperonin CCT via a ternary complex.","date":"2009","source":"Journal of molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/19501098","citation_count":32,"is_preprint":false},{"pmid":"23792958","id":"PMC_23792958","title":"Identification of PDCL3 as a novel chaperone protein involved in the generation of functional VEGF receptor 2.","date":"2013","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23792958","citation_count":30,"is_preprint":false},{"pmid":"32621347","id":"PMC_32621347","title":"Fetal megacystis-microcolon: Genetic mutational spectrum and identification of PDCL3 as a novel candidate gene.","date":"2020","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/32621347","citation_count":21,"is_preprint":false},{"pmid":"29384851","id":"PMC_29384851","title":"Identifying protein biomarkers in predicting disease severity of dengue virus infection using immune-related protein microarray.","date":"2018","source":"Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/29384851","citation_count":21,"is_preprint":false},{"pmid":"38643947","id":"PMC_38643947","title":"Identification and validation of cuproptosis and disulfidptosis related genes in colorectal cancer.","date":"2024","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/38643947","citation_count":9,"is_preprint":false},{"pmid":"40469100","id":"PMC_40469100","title":"PDCL3 promotes the vasculogenic mimicry of glioma-associated mesenchymal stem cells through VEGFR-2 in glioma environment.","date":"2025","source":"iScience","url":"https://pubmed.ncbi.nlm.nih.gov/40469100","citation_count":3,"is_preprint":false},{"pmid":"35011190","id":"PMC_35011190","title":"Identification of Monoallelically Expressed Genes Associated with Economic Traits in Hanwoo (Korean Native Cattle).","date":"2021","source":"Animals : an open access journal from MDPI","url":"https://pubmed.ncbi.nlm.nih.gov/35011190","citation_count":3,"is_preprint":false},{"pmid":"41639907","id":"PMC_41639907","title":"Proteomic profiles in inclusion body myositis and polymyositis with mitochondrial pathology.","date":"2026","source":"Acta neuropathologica communications","url":"https://pubmed.ncbi.nlm.nih.gov/41639907","citation_count":1,"is_preprint":false},{"pmid":"15790111","id":"PMC_15790111","title":"Extraction mechanism for palladium(II) from hydrochloric acid solution with 2-dodecylthiomethylpyridine using a stirred transfer cell.","date":"2005","source":"Analytical sciences : the international journal of the Japan Society for Analytical Chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/15790111","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7746,"output_tokens":1536,"usd":0.023139,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8244,"output_tokens":2443,"usd":0.051147,"stage2_stop_reason":"end_turn"},"total_usd":0.074286,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2013,\n      \"finding\": \"PDCL3 was identified as a chaperone protein that binds to the juxtamembrane domain of VEGFR-2, inhibits its ubiquitination and proteasomal degradation, and thereby controls VEGFR-2 surface abundance. PDCL3 also increases VEGF-induced tyrosine phosphorylation of VEGFR-2 and is required for VEGFR-2-dependent endothelial capillary tube formation and proliferation.\",\n      \"method\": \"Yeast two-hybrid screen, co-immunoprecipitation, siRNA knockdown, VEGFR-2 ubiquitination assay, endothelial tube formation and proliferation assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal binding assay (yeast two-hybrid + Co-IP), functional ubiquitination assay, and multiple cellular phenotypic readouts in a single focused mechanistic study\",\n      \"pmids\": [\"23792958\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"PDCL3 undergoes N-terminal methionine acetylation, and this modification is required for its hypoxia-induced upregulation and for its interaction with VEGFR-2. A mutant PDCL3 unable to undergo N-terminal methionine acetylation is refractory to hypoxia. PDCL3 also protects VEGFR-2 from misfolding and aggregation, and is required for angiogenesis in zebrafish and mouse models.\",\n      \"method\": \"Mass spectrometry (N-terminal acetylation identification), site-directed mutagenesis of acetylation site, siRNA knockdown, VEGFR-2 protein aggregation assay, in vivo zebrafish and mouse angiogenesis models\",\n      \"journal\": \"Angiogenesis\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — PTM identified by MS, validated by mutagenesis, functional consequences tested in vitro and in vivo across two model organisms\",\n      \"pmids\": [\"26059764\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Human PDCL3 (ortholog of yeast PLP2) acts as an inhibitory regulator of CCT (chaperonin-containing TCP-1)-mediated folding of beta-actin in vitro and in vivo. This inhibitory activity is conferred by PDCL3's acidic C-terminal extension, since replacing it with the C-terminal extension of yeast PLP2 relieves the inhibition. In contrast, yeast PLP2 is a stimulatory co-factor for CCT-mediated actin folding, forming a ternary PLP2-CCT-actin complex.\",\n      \"method\": \"In vitro CCT-actin folding assay using rabbit reticulocyte lysate translation system, C-terminal domain swap mutagenesis, in vitro reconstitution with purified yeast components\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution of folding assay combined with mutagenesis (domain swap) in a single rigorous study\",\n      \"pmids\": [\"19501098\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Compound heterozygous loss-of-function variants in PDCL3 (c.[143_144del];[380G>A]) were identified in patients with megacystis-microcolon-intestinal-hypoperistalsis syndrome (MMIHS). cDNA analysis showed complete absence of PDCL3 expression in affected individuals due to nonsense-mediated mRNA decay, implicating PDCL3's actin-folding chaperone function in smooth muscle contractility.\",\n      \"method\": \"Exome sequencing, cDNA expression analysis (nonsense-mediated decay confirmation)\",\n      \"journal\": \"Clinical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Weak — genetic identification of loss-of-function variants with mRNA decay confirmation, single study, no direct in vitro functional rescue experiment\",\n      \"pmids\": [\"32621347\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In glioma-associated mesenchymal stem cells (GA-MSCs), PDCL3 upregulation promotes expression of VEGFR-2 and pericyte markers, facilitating transformation of GA-MSCs into pericytes and enhancing vasculogenic mimicry when co-cultured with HUVECs.\",\n      \"method\": \"siRNA knockdown of PDCL3, overexpression experiments, co-culture vasculogenic mimicry assay, Western blot for VEGFR-2 and pericyte markers\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, loss-of-function and overexpression with cellular phenotype readouts but limited mechanistic dissection beyond VEGFR-2 axis\",\n      \"pmids\": [\"40469100\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"PDCL3 is a chaperone protein that (1) folds actin in a CCT-dependent manner but acts as an inhibitor (not activator) of CCT-mediated beta-actin folding via its acidic C-terminal extension, and (2) stabilizes VEGFR-2 by binding its juxtamembrane domain, blocking ubiquitination and degradation, and protecting it from misfolding—a function regulated by hypoxia-induced N-terminal methionine acetylation—thereby promoting angiogenesis; loss-of-function mutations in PDCL3 cause defective smooth muscle contractility manifesting as MMIHS.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PDCL3 is a phosducin-like chaperone protein that operates in two distinct cellular contexts: cytoskeletal protein folding and receptor tyrosine kinase stabilization [#0, #2]. As the human ortholog of yeast PLP2, PDCL3 engages the CCT (chaperonin-containing TCP-1) chaperonin to regulate beta-actin folding, but unlike its stimulatory yeast counterpart it acts as an inhibitor of CCT-mediated actin folding, an activity conferred by its acidic C-terminal extension [#2]. In endothelial cells, PDCL3 binds the juxtamembrane domain of VEGFR-2, blocks its ubiquitination and proteasomal degradation, protects the receptor from misfolding and aggregation, and thereby raises VEGFR-2 surface abundance and VEGF-induced tyrosine phosphorylation to drive endothelial proliferation, capillary tube formation, and angiogenesis in zebrafish and mouse models [#0, #1]. This VEGFR-2-stabilizing function is gated by N-terminal methionine acetylation of PDCL3, a modification required for its hypoxia-induced upregulation and its interaction with VEGFR-2 [#1]. The same VEGFR-2 axis is co-opted in glioma-associated mesenchymal stem cells, where PDCL3 upregulation promotes their conversion to pericytes and enhances vasculogenic mimicry [#4]. Compound heterozygous loss-of-function variants in PDCL3 cause megacystis-microcolon-intestinal-hypoperistalsis syndrome (MMIHS), linking its actin-folding chaperone role to smooth muscle contractility [#3].\",\n  \"teleology\": [\n    {\n      \"year\": 2009,\n      \"claim\": \"Established whether human PDCL3 modulates CCT-dependent cytoskeletal protein folding, and whether it shares the function of its yeast ortholog, defining its core chaperone identity.\",\n      \"evidence\": \"In vitro CCT-actin folding assay in reticulocyte lysate with C-terminal domain-swap mutagenesis and reconstitution using purified yeast components\",\n      \"pmids\": [\"19501098\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Mechanism by which the acidic C-terminal extension inhibits CCT not structurally resolved\",\n        \"Cellular consequences of actin-folding inhibition in specific tissues not defined\",\n        \"Does not address PDCL3's role outside the cytoskeleton\"\n      ]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identified PDCL3 as a direct binding partner and stabilizer of VEGFR-2, answering how the receptor's surface abundance is controlled and extending PDCL3's chaperone role to receptor tyrosine kinase signaling.\",\n      \"evidence\": \"Yeast two-hybrid screen, co-immunoprecipitation, siRNA knockdown, VEGFR-2 ubiquitination assay, and endothelial tube formation/proliferation assays\",\n      \"pmids\": [\"23792958\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis of juxtamembrane-domain binding not resolved\",\n        \"Whether VEGFR-2 stabilization requires the CCT machinery not addressed\",\n        \"Identity of the ubiquitin ligase blocked by PDCL3 not defined\"\n      ]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined the upstream regulatory input controlling PDCL3's VEGFR-2 function, showing that N-terminal methionine acetylation couples hypoxia to receptor stabilization and angiogenesis in vivo.\",\n      \"evidence\": \"Mass spectrometry PTM identification, acetylation-site mutagenesis, protein aggregation assay, and zebrafish and mouse angiogenesis models\",\n      \"pmids\": [\"26059764\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Enzyme(s) responsible for hypoxia-regulated N-terminal acetylation not identified\",\n        \"How acetylation mechanistically promotes VEGFR-2 binding unclear\",\n        \"Relationship between the actin-folding and VEGFR-2 functions not integrated\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Linked PDCL3 to human disease, showing that biallelic loss-of-function causes MMIHS and implicating its chaperone function in smooth muscle contractility.\",\n      \"evidence\": \"Exome sequencing and cDNA analysis confirming nonsense-mediated decay in affected individuals\",\n      \"pmids\": [\"32621347\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No direct in vitro functional rescue experiment performed\",\n        \"Whether the actin-folding or another function underlies the smooth muscle defect not established\",\n        \"Single study without independent patient cohort\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Extended the PDCL3-VEGFR-2 axis to a tumor microenvironment context, showing PDCL3 drives mesenchymal-to-pericyte transformation and vasculogenic mimicry.\",\n      \"evidence\": \"siRNA knockdown and overexpression in glioma-associated mesenchymal stem cells with co-culture vasculogenic mimicry assays and Western blot\",\n      \"pmids\": [\"40469100\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanistic dissection limited to the VEGFR-2 readout\",\n        \"Single lab without in vivo tumor confirmation\",\n        \"Whether PDCL3 acetylation/hypoxia regulation operates in this context untested\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How PDCL3's two activities — CCT-coupled actin folding and VEGFR-2 stabilization — are mechanistically and structurally related, and which underlies each disease phenotype, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No structural model of PDCL3 in either complex\",\n        \"No unified mechanism connecting actin and VEGFR-2 functions\",\n        \"Acetyltransferase and deubiquitination/ligase partners unidentified\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0044183\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"localization\": [],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"complexes\": [\"CCT/TRiC\"],\n    \"partners\": [\"KDR\", \"CCT/TCP-1\", \"ACTB\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}