{"gene":"HPS3","run_date":"2026-06-10T01:55:22","timeline":{"discoveries":[{"year":2001,"finding":"HPS3 was identified as a novel gene on chromosome 3q24 encoding a predicted 113.7-kD protein, with a homozygous large deletion (3904-bp founder deletion removing exon 1) causing HPS-3 disease in a genetic isolate of central Puerto Rico, implicating it in vesicle formation in specialized cells.","method":"Homozygosity mapping on pooled DNA, gene cloning, mutation analysis","journal":"Nature genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — positional cloning with mutation identification; single study but foundational gene discovery with clear disease linkage","pmids":["11455388"],"is_preprint":false},{"year":2003,"finding":"HPS3 protein was identified as a soluble and membrane-associated protein in HeLa cells; unlike HPS4, HPS3 does NOT associate with HPS1 in the BLOC-3 complex, establishing that HPS3 functions in a distinct complex from HPS1/HPS4.","method":"Sedimentation-velocity experiments, coimmunoprecipitation from HeLa cell extracts","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal biochemical fractionation and co-IP; single lab, two orthogonal methods","pmids":["12847290"],"is_preprint":false},{"year":2004,"finding":"HPS3, HPS5, and HPS6 proteins form a stable ~340 kDa protein complex called BLOC-2 (Biogenesis of Lysosome-related Organelles Complex-2), demonstrated by coimmunoprecipitation from HeLa cell extracts and by size-exclusion chromatography and density gradient centrifugation. BLOC-2 exists in both a soluble pool and associates with membranes as a peripheral membrane protein.","method":"Coimmunoprecipitation, size-exclusion chromatography, density gradient centrifugation","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal biochemical methods (co-IP, gel filtration, density gradient) in one study, independently replicated in mouse tissues (PMID:14718540)","pmids":["15030569"],"is_preprint":false},{"year":2004,"finding":"In mouse tissues, Hps3, Hps5, and Hps6 proteins co-immunoprecipitate and co-sediment in a ~350 kDa complex (BLOC-2). Hps5 protein is destabilized in Hps3 and Hps6 mutant tissues, and Hps6 protein is destabilized in Hps3 and Hps5 mutant tissues, indicating mutual stabilization within BLOC-2. Genetic epistasis (double-mutant mice with identical phenotypes to single mutants) confirms they act within the same pathway for vesicle trafficking to lysosome-related organelles.","method":"Coimmunoprecipitation, sucrose gradient sedimentation, gel filtration, Western blot of mutant mouse tissues, double-mutant genetic epistasis analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (co-IP, sedimentation, genetic epistasis) in mouse in vivo system, corroborating cell-line data from PMID:15030569","pmids":["14718540"],"is_preprint":false},{"year":2005,"finding":"HPS3 associates with clathrin via a functional clathrin-binding motif (LLDFE at residues 172–176). Clathrin was co-immunoprecipitated by HPS3 antibodies from normal but not HPS3-null melanocytes. GFP-HPS3 co-localizes with clathrin on small vesicles in the perinuclear region during a 20°C temperature block, while a GFP-HPS3 clathrin-binding-domain deletion mutant (GFP-HPS3-delCBD) fails to co-localize with clathrin and shows a largely cytoplasmic distribution.","method":"Coimmunoprecipitation from melanocytes, live-cell fluorescence microscopy with temperature block, immunoelectron microscopy, domain deletion mutagenesis","journal":"BMC cell biology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — co-IP, immunoEM, and domain-deletion mutagenesis in the same study with appropriate null-cell controls","pmids":["16159387"],"is_preprint":false},{"year":2005,"finding":"In HPS-3 patient melanocytes, a specific subset of melanocyte proteins — tyrosinase, Tyrp1, Dct, LAMP1, and LAMP3 — show aberrant fine, floccular (rather than coarse granular) distribution, while Silver/Pmel17, Melan-A/MART-1, LAMP2, Rab27, transferrin, c-Kit, adaptin-3, and HPS1 protein localization appears normal, indicating HPS3 selectively controls trafficking of a subset of melanocyte cargo proteins.","method":"Immunocytochemistry and confocal microscopy on patient-derived melanocytes, ultrastructural analysis, DOPA histochemistry","journal":"The American journal of pathology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct protein localization with patient-derived null cells and multiple cargo markers; single lab","pmids":["15632015"],"is_preprint":false},{"year":2005,"finding":"In HPS-3 and HPS-1 patient melanocytes, tyrosinase, Tyrp1, and Dct/Tyrp2 are atypically distributed, whereas in HPS-2 melanocytes only tyrosinase shows atypical distribution. In HPS-3 melanocytes, LAMP1 and LAMP3 show a distinct less granular, more floccular pattern; HPS3 melanocytes express normal HPS1 and AP3B1 proteins.","method":"Immunofluorescence microscopy on patient-derived melanocytes, Western blot","journal":"The Journal of investigative dermatology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — comparative immunofluorescence across three HPS patient genotypes; single lab with multiple markers","pmids":["15675963"],"is_preprint":false},{"year":2009,"finding":"Functional deletion of HPS3 (HPS3−/− mice) markedly reduces platelet dense-granule secretion without affecting platelet counts, platelet morphology, alpha-granule number, or maximal P-selectin secretion. HPS3-deficient mice show significantly reduced capacity to form platelet-leukocyte aggregates, and are completely resistant to thrombotic arterial occlusion after FeCl3 injury, demonstrating HPS3's specific role in dense-granule biogenesis/secretion.","method":"Mouse knockout model, platelet function assays, flow cytometry, in vivo carotid artery thrombosis model","journal":"Circulation","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO with defined cellular and in vivo phenotypes; multiple orthogonal assays establishing HPS3's specific role in dense-granule secretion","pmids":["19687360"],"is_preprint":false},{"year":2013,"finding":"In zebrafish, an Hps5 missense mutation (hps5I76N) within the N-terminal WD40 repeat domain disrupts melanosome biogenesis; in vitro coexpression assays show that Hps5I76N retains the ability to bind its BLOC-2 complex partners Hps3 and Hps6, but the mutual stabilization between Hps5 and Hps6 is disrupted by this allele, establishing that the WD40 domain of Hps5 is important for inter-subunit stabilization within BLOC-2.","method":"In vitro coexpression binding assay, Western blot for protein stability, zebrafish genetic model","journal":"Genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro coexpression with mutagenesis and zebrafish in vivo model; single lab","pmids":["23893484"],"is_preprint":false},{"year":2018,"finding":"In Chinese HPS patients with mutations in HPS3 (as well as HPS5, HPS6), the respective partner subunits of BLOC-2 are destabilized, confirming that BLOC-2 integrity depends on all its subunits including HPS3.","method":"Western blot of patient-derived cells after NGS-identified mutations","journal":"Pigment cell & melanoma research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct protein stability assessment in patient cells; independent replication of complex-stability finding from earlier mouse and cell-line studies","pmids":["30387913"],"is_preprint":false},{"year":2024,"finding":"BLOC-2 (containing HPS3, HPS5, HPS6 and a fourth Claret-ortholog subunit) is recruited to endolysosomes via its HPS3 subunit in Dictyostelium. In BLOC-2 mutants, WASH complex recruitment is inefficient, causing failure of lysosome maturation. Structural modeling suggests all four BLOC-2 subunits are proto-coatomer proteins, indicating BLOC-2 acts as a coat-like complex at endolysosomes.","method":"Dictyostelium genetic mutant analysis, WASH localization imaging, structural homology modeling, live-cell imaging of BLOC-2 compartment localization","journal":"Current biology : CB","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic mutant analysis with localization imaging and structural modeling; single study in a non-mammalian model organism with functional validation","pmids":["39059394"],"is_preprint":false}],"current_model":"HPS3 is a subunit of BLOC-2 (Biogenesis of Lysosome-related Organelles Complex-2), a ~340 kDa peripheral membrane complex also containing HPS5 and HPS6, in which HPS3 is required for complex integrity and mutual stabilization of subunits; HPS3 localizes to perinuclear clathrin-containing vesicles via a direct clathrin-binding motif (LLDFE), is recruited to endolysosomes where it facilitates WASH complex recruitment and lysosome maturation, and is specifically required for the trafficking of tyrosinase, Tyrp1, Dct, and LAMP1/3 to melanosomes in melanocytes and for platelet dense-granule biogenesis/secretion."},"narrative":{"mechanistic_narrative":"HPS3 is a subunit of BLOC-2, a stable ~340 kDa peripheral membrane complex it forms with HPS5 and HPS6 that directs cargo trafficking to lysosome-related organelles [PMID:15030569, PMID:14718540]. HPS3 functions in a complex distinct from the HPS1/HPS4-containing BLOC-3, with which it does not associate [PMID:12847290]. Within BLOC-2, the subunits are mutually stabilizing: loss of HPS3 destabilizes HPS5 and HPS6 in both mouse tissues and human patient cells, establishing that complex integrity depends on all subunits [PMID:14718540, PMID:30387913]. HPS3 carries a functional clathrin-binding motif (LLDFE, residues 172–176) through which it associates with clathrin on perinuclear vesicles, and deletion of this motif abolishes clathrin co-localization and renders the protein cytoplasmic [PMID:16159387]. Functionally, HPS3 selectively controls trafficking of a defined subset of melanocyte cargo — tyrosinase, Tyrp1, Dct, and LAMP1/LAMP3 — to melanosomes, with other melanosomal and endosomal markers unaffected [PMID:15632015, PMID:15675963], and is independently required for platelet dense-granule biogenesis and secretion, such that its loss in mice abolishes dense-granule-dependent thrombus formation [PMID:19687360]. At endolysosomes, the HPS3 subunit recruits BLOC-2 to the compartment where it promotes WASH complex recruitment and lysosome maturation [PMID:39059394]. Loss-of-function mutation of HPS3 causes Hermansky-Pudlak syndrome type 3 [PMID:11455388].","teleology":[{"year":2001,"claim":"Established HPS3 as a disease gene by linking a founder deletion to a distinct form of Hermansky-Pudlak syndrome, implicating it in vesicle formation in specialized cells.","evidence":"Homozygosity mapping and positional cloning with mutation analysis in a Puerto Rican genetic isolate","pmids":["11455388"],"confidence":"Medium","gaps":["No molecular function or interacting partners defined","Cell-type-specific trafficking role not yet demonstrated"]},{"year":2003,"claim":"Resolved which complex HPS3 belongs to by showing it does not associate with HPS1, distinguishing its pathway from the BLOC-3 (HPS1/HPS4) complex.","evidence":"Sedimentation-velocity fractionation and co-immunoprecipitation from HeLa cell extracts","pmids":["12847290"],"confidence":"Medium","gaps":["Did not identify HPS3's own complex partners","Membrane association unexplained"]},{"year":2004,"claim":"Defined the BLOC-2 complex by demonstrating that HPS3, HPS5, and HPS6 assemble into a single ~340 kDa peripheral membrane complex with mutually dependent subunit stability.","evidence":"Co-IP, size-exclusion chromatography, and density gradient centrifugation in HeLa cells, plus mouse tissue co-sedimentation and double-mutant epistasis","pmids":["15030569","14718540"],"confidence":"High","gaps":["Stoichiometry and architecture not resolved","Molecular activity of the complex undefined","Membrane recruitment mechanism unknown"]},{"year":2005,"claim":"Provided a mechanistic link to membrane trafficking machinery by identifying a functional clathrin-binding motif in HPS3 mediating localization to perinuclear clathrin-coated vesicles.","evidence":"Co-IP from melanocytes, temperature-block live-cell imaging, immunoEM, and clathrin-binding-domain deletion mutagenesis","pmids":["16159387"],"confidence":"High","gaps":["Functional consequence of clathrin binding for cargo sorting not directly tested","Whether other BLOC-2 subunits also engage clathrin unknown"]},{"year":2005,"claim":"Defined the cargo specificity of HPS3 by showing it selectively controls melanosomal delivery of a defined subset of proteins while sparing other markers.","evidence":"Immunocytochemistry, confocal and ultrastructural analysis of HPS-3 patient-derived melanocytes across multiple cargo markers, including comparison with HPS-1 and HPS-2","pmids":["15632015","15675963"],"confidence":"Medium","gaps":["Mechanism distinguishing affected from unaffected cargo not established","Direct cargo recognition by BLOC-2 not demonstrated"]},{"year":2009,"claim":"Demonstrated a second physiological role beyond pigmentation by showing HPS3 is specifically required for platelet dense-granule biogenesis and secretion-dependent thrombosis.","evidence":"HPS3-knockout mouse platelet function assays, flow cytometry, and in vivo FeCl3 arterial thrombosis model","pmids":["19687360"],"confidence":"High","gaps":["Molecular step within dense-granule biogenesis controlled by HPS3 not pinpointed","Whether the clathrin/BLOC-2 mechanism operates identically in platelets unaddressed"]},{"year":2013,"claim":"Localized the inter-subunit stabilization function within BLOC-2 to the HPS5 WD40 domain, refining how complex integrity is maintained while confirming HPS3-HPS5-HPS6 binding.","evidence":"In vitro coexpression binding/stability assays with an HPS5 WD40 missense allele and a zebrafish melanosome-biogenesis model","pmids":["23893484"],"confidence":"Medium","gaps":["HPS3's own contribution to stabilization not mapped to a domain","Structural basis of the complex still unresolved"]},{"year":2018,"claim":"Confirmed in human patients that BLOC-2 integrity depends on all subunits, including HPS3, generalizing the mutual-stabilization model across species.","evidence":"Western blot of partner subunit levels in HPS3/HPS5/HPS6-mutant patient cells identified by NGS","pmids":["30387913"],"confidence":"Medium","gaps":["Does not add mechanistic detail beyond stability dependence"]},{"year":2024,"claim":"Elucidated a coat-like mechanism by which BLOC-2 is recruited to endolysosomes through HPS3 to drive WASH recruitment and lysosome maturation.","evidence":"Dictyostelium genetic mutant analysis, WASH localization imaging, live-cell BLOC-2 compartment imaging, and proto-coatomer structural homology modeling","pmids":["39059394"],"confidence":"Medium","gaps":["Proto-coatomer model is structural prediction, not experimental structure","Mechanism of HPS3-mediated endolysosome recruitment not defined at residue level","Conservation of the WASH-recruitment role in mammalian melanocytes/platelets untested"]},{"year":null,"claim":"How BLOC-2 recognizes its specific cargo subset and the precise molecular activity (coat versus tether versus adaptor) HPS3 contributes at endolysosomal membranes remain undefined.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No experimental structure of BLOC-2 or HPS3","Direct cargo-recognition mechanism unproven","Biochemical activity of HPS3 not assigned"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[4,10]}],"localization":[{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[4]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[2,4]},{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[10]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[10]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[2,5]},{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[5,10]}],"complexes":["BLOC-2"],"partners":["HPS5","HPS6","CLTC"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q969F9","full_name":"BLOC-2 complex member HPS3","aliases":["Hermansky-Pudlak syndrome 3 protein"],"length_aa":1004,"mass_kda":113.7,"function":"Involved in early stages of melanosome biogenesis and maturation","subcellular_location":"Cytoplasm; Cytoplasm, cytosol","url":"https://www.uniprot.org/uniprotkb/Q969F9/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/HPS3","classification":"Not Classified","n_dependent_lines":5,"n_total_lines":1208,"dependency_fraction":0.0041390728476821195},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"FKBP5","stoichiometry":0.2},{"gene":"FKBP8","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/HPS3","total_profiled":1310},"omim":[{"mim_id":"619946","title":"MCF.2 CELL LINE-DERIVED TRANSFORMING SEQUENCE-LIKE 2; MCF2L2","url":"https://www.omim.org/entry/619946"},{"mim_id":"614075","title":"HERMANSKY-PUDLAK SYNDROME 6; HPS6","url":"https://www.omim.org/entry/614075"},{"mim_id":"614072","title":"HERMANSKY-PUDLAK SYNDROME 3; HPS3","url":"https://www.omim.org/entry/614072"},{"mim_id":"607145","title":"DYSTROBREVIN-BINDING PROTEIN 1; DTNBP1","url":"https://www.omim.org/entry/607145"},{"mim_id":"606118","title":"HPS3 BIOGENESIS OF LYSOSOMAL ORGANELLES COMPLEX 2, SUBUNIT 1; HPS3","url":"https://www.omim.org/entry/606118"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Golgi apparatus","reliability":"Approved"},{"location":"Plasma membrane","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/HPS3"},"hgnc":{"alias_symbol":["SUTAL","BLOC2S1"],"prev_symbol":[]},"alphafold":{"accession":"Q969F9","domains":[{"cath_id":"2.130.10.10","chopping":"4-217_256-324_339-451","consensus_level":"medium","plddt":87.5047,"start":4,"end":451},{"cath_id":"-","chopping":"771-902","consensus_level":"medium","plddt":84.7124,"start":771,"end":902},{"cath_id":"1.25.40","chopping":"903-1001","consensus_level":"medium","plddt":85.3139,"start":903,"end":1001}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q969F9","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q969F9-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q969F9-F1-predicted_aligned_error_v6.png","plddt_mean":82.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=HPS3","jax_strain_url":"https://www.jax.org/strain/search?query=HPS3"},"sequence":{"accession":"Q969F9","fasta_url":"https://rest.uniprot.org/uniprotkb/Q969F9.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q969F9/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q969F9"}},"corpus_meta":[{"pmid":"11455388","id":"PMC_11455388","title":"Mutation of a new gene causes a unique form of Hermansky-Pudlak syndrome in a genetic isolate of central Puerto Rico.","date":"2001","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/11455388","citation_count":166,"is_preprint":false},{"pmid":"11836498","id":"PMC_11836498","title":"Hermansky-Pudlak syndrome is caused by mutations in HPS4, the human homolog of the mouse light-ear gene.","date":"2002","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/11836498","citation_count":147,"is_preprint":false},{"pmid":"12847290","id":"PMC_12847290","title":"Biogenesis of lysosome-related organelles complex 3 (BLOC-3): a complex containing the Hermansky-Pudlak syndrome (HPS) proteins HPS1 and HPS4.","date":"2003","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/12847290","citation_count":107,"is_preprint":false},{"pmid":"12664304","id":"PMC_12664304","title":"Hermansky-Pudlak syndrome type 4 (HPS-4): clinical and molecular characteristics.","date":"2003","source":"Human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/12664304","citation_count":106,"is_preprint":false},{"pmid":"15030569","id":"PMC_15030569","title":"Characterization of BLOC-2, a complex containing the Hermansky-Pudlak syndrome proteins HPS3, HPS5 and HPS6.","date":"2004","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/15030569","citation_count":87,"is_preprint":false},{"pmid":"12453182","id":"PMC_12453182","title":"Hermansky-Pudlak syndrome: vesicle formation from yeast to man.","date":"2002","source":"Pigment cell research","url":"https://pubmed.ncbi.nlm.nih.gov/12453182","citation_count":84,"is_preprint":false},{"pmid":"12125811","id":"PMC_12125811","title":"Disorders of vesicles of lysosomal lineage: the Hermansky-Pudlak syndromes.","date":"2002","source":"Current molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/12125811","citation_count":75,"is_preprint":false},{"pmid":"11590544","id":"PMC_11590544","title":"Hermansky-Pudlak syndrome type 3 in Ashkenazi Jews and other non-Puerto Rican patients with hypopigmentation and platelet storage-pool deficiency.","date":"2001","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/11590544","citation_count":68,"is_preprint":false},{"pmid":"14718540","id":"PMC_14718540","title":"The Hermansky-Pudlak syndrome 3 (cocoa) protein is a component of the biogenesis of lysosome-related organelles complex-2 (BLOC-2).","date":"2004","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/14718540","citation_count":66,"is_preprint":false},{"pmid":"19687360","id":"PMC_19687360","title":"Platelet dense-granule secretion plays a critical role in thrombosis and subsequent vascular remodeling in atherosclerotic mice.","date":"2009","source":"Circulation","url":"https://pubmed.ncbi.nlm.nih.gov/19687360","citation_count":57,"is_preprint":false},{"pmid":"20042077","id":"PMC_20042077","title":"Genetic determinants of hair and eye colours in the Scottish and Danish populations.","date":"2009","source":"BMC genetics","url":"https://pubmed.ncbi.nlm.nih.gov/20042077","citation_count":50,"is_preprint":false},{"pmid":"12442288","id":"PMC_12442288","title":"Hermansky-Pudlak syndrome type 1: gene organization, novel mutations, and clinical-molecular review of non-Puerto Rican cases.","date":"2002","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/12442288","citation_count":49,"is_preprint":false},{"pmid":"16417222","id":"PMC_16417222","title":"Genetic testing for oculocutaneous albinism type 1 and 2 and Hermansky-Pudlak syndrome type 1 and 3 mutations in Puerto Rico.","date":"2006","source":"The Journal of investigative dermatology","url":"https://pubmed.ncbi.nlm.nih.gov/16417222","citation_count":47,"is_preprint":false},{"pmid":"15675963","id":"PMC_15675963","title":"Melanocytes derived from patients with Hermansky-Pudlak Syndrome types 1, 2, and 3 have distinct defects in cargo trafficking.","date":"2005","source":"The Journal of investigative dermatology","url":"https://pubmed.ncbi.nlm.nih.gov/15675963","citation_count":47,"is_preprint":false},{"pmid":"15265785","id":"PMC_15265785","title":"Reduced pigmentation (rp), a mouse model of Hermansky-Pudlak syndrome, encodes a novel component of the BLOC-1 complex.","date":"2004","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/15265785","citation_count":43,"is_preprint":false},{"pmid":"19843503","id":"PMC_19843503","title":"Clinical and cellular characterisation of Hermansky-Pudlak syndrome type 6.","date":"2009","source":"Journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19843503","citation_count":39,"is_preprint":false},{"pmid":"15632015","id":"PMC_15632015","title":"Melanocyte-specific proteins are aberrantly trafficked in melanocytes of Hermansky-Pudlak syndrome-type 3.","date":"2005","source":"The American journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/15632015","citation_count":36,"is_preprint":false},{"pmid":"17301833","id":"PMC_17301833","title":"Improper trafficking of melanocyte-specific proteins in Hermansky-Pudlak syndrome type-5.","date":"2007","source":"The Journal of investigative dermatology","url":"https://pubmed.ncbi.nlm.nih.gov/17301833","citation_count":34,"is_preprint":false},{"pmid":"31141302","id":"PMC_31141302","title":"NGS-based targeted resequencing identified rare subtypes of albinism: Providing accurate molecular diagnosis for Japanese patients with albinism.","date":"2019","source":"Pigment cell & melanoma research","url":"https://pubmed.ncbi.nlm.nih.gov/31141302","citation_count":30,"is_preprint":false},{"pmid":"27593200","id":"PMC_27593200","title":"NGS-based 100-gene panel of hypopigmentation identifies mutations in Chinese Hermansky-Pudlak syndrome patients.","date":"2016","source":"Pigment cell & melanoma research","url":"https://pubmed.ncbi.nlm.nih.gov/27593200","citation_count":29,"is_preprint":false},{"pmid":"15108212","id":"PMC_15108212","title":"Hermansky-Pudlak syndrome type 4 in a patient from Sri Lanka with pulmonary fibrosis.","date":"2004","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/15108212","citation_count":29,"is_preprint":false},{"pmid":"23893484","id":"PMC_23893484","title":"snow white, a zebrafish model of Hermansky-Pudlak Syndrome type 5.","date":"2013","source":"Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/23893484","citation_count":26,"is_preprint":false},{"pmid":"32969595","id":"PMC_32969595","title":"Current landscape of Oculocutaneous Albinism in Japan.","date":"2020","source":"Pigment cell & melanoma research","url":"https://pubmed.ncbi.nlm.nih.gov/32969595","citation_count":25,"is_preprint":false},{"pmid":"20130740","id":"PMC_20130740","title":"Antidiabetic properties of purified polysaccharide from Hedysarum polybotrys.","date":"2010","source":"Canadian journal of physiology and pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/20130740","citation_count":24,"is_preprint":false},{"pmid":"33513603","id":"PMC_33513603","title":"A zinc transporter, transmembrane protein 163, is critical for the biogenesis of platelet dense granules.","date":"2021","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/33513603","citation_count":21,"is_preprint":false},{"pmid":"33423334","id":"PMC_33423334","title":"Inflammatory bowel disease in Hermansky-Pudlak syndrome: a retrospective single-centre cohort study.","date":"2021","source":"Journal of internal medicine","url":"https://pubmed.ncbi.nlm.nih.gov/33423334","citation_count":20,"is_preprint":false},{"pmid":"17041891","id":"PMC_17041891","title":"A new genetic isolate with a unique phenotype of syndromic oculocutaneous albinism: clinical, molecular, and cellular characteristics.","date":"2006","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/17041891","citation_count":19,"is_preprint":false},{"pmid":"30387913","id":"PMC_30387913","title":"Instability of BLOC-2 and BLOC-3 in Chinese patients with Hermansky-Pudlak syndrome.","date":"2018","source":"Pigment cell & melanoma research","url":"https://pubmed.ncbi.nlm.nih.gov/30387913","citation_count":18,"is_preprint":false},{"pmid":"16159387","id":"PMC_16159387","title":"Association of the Hermansky-Pudlak syndrome type-3 protein with clathrin.","date":"2005","source":"BMC cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/16159387","citation_count":15,"is_preprint":false},{"pmid":"32502225","id":"PMC_32502225","title":"Human exome and mouse embryonic expression data implicate ZFHX3, TRPS1, and CHD7 in human esophageal atresia.","date":"2020","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/32502225","citation_count":14,"is_preprint":false},{"pmid":"25037407","id":"PMC_25037407","title":"Structural characterization and stimulating effect on osteoblast differentiation of a purified heteropolysaccharide isolated from Hedysarum polybotrys.","date":"2014","source":"Carbohydrate polymers","url":"https://pubmed.ncbi.nlm.nih.gov/25037407","citation_count":14,"is_preprint":false},{"pmid":"32725903","id":"PMC_32725903","title":"Genetic variants and mutational spectrum of Chinese Hermansky-Pudlak syndrome patients.","date":"2020","source":"Pigment cell & melanoma research","url":"https://pubmed.ncbi.nlm.nih.gov/32725903","citation_count":14,"is_preprint":false},{"pmid":"38786974","id":"PMC_38786974","title":"Cholesteryl Ester Transfer Protein Inhibitors and Cardiovascular Outcomes: A Systematic Review and Meta-Analysis.","date":"2024","source":"Journal of cardiovascular development and disease","url":"https://pubmed.ncbi.nlm.nih.gov/38786974","citation_count":13,"is_preprint":false},{"pmid":"35905627","id":"PMC_35905627","title":"Triphenyltin exposure induced abnormal morphological colouration in adult male guppies (Poecilia reticulata).","date":"2022","source":"Ecotoxicology and environmental safety","url":"https://pubmed.ncbi.nlm.nih.gov/35905627","citation_count":13,"is_preprint":false},{"pmid":"28640947","id":"PMC_28640947","title":"Clinico-molecular analysis of eleven patients with Hermansky-Pudlak type 5 syndrome, a mild form of HPS.","date":"2017","source":"Pigment cell & melanoma research","url":"https://pubmed.ncbi.nlm.nih.gov/28640947","citation_count":13,"is_preprint":false},{"pmid":"33808351","id":"PMC_33808351","title":"Prospective Study of the Phenotypic and Mutational Spectrum of Ocular Albinism and Oculocutaneous Albinism.","date":"2021","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/33808351","citation_count":12,"is_preprint":false},{"pmid":"28284561","id":"PMC_28284561","title":"Novel mutation in two brothers with Hermansky Pudlak syndrome type 3.","date":"2017","source":"Blood cells, molecules & diseases","url":"https://pubmed.ncbi.nlm.nih.gov/28284561","citation_count":11,"is_preprint":false},{"pmid":"17567547","id":"PMC_17567547","title":"A large analphoid invdup(3)(q22.3qter) marker chromosome characterized by array-CGH in a child with malformations, mental retardation, ambiguous genitalia and Blaschko's lines.","date":"2007","source":"European journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/17567547","citation_count":11,"is_preprint":false},{"pmid":"35126127","id":"PMC_35126127","title":"Hermansky-Pudlak Syndrome: Identification of Novel Variants in the Genes HPS3, HPS5, and DTNBP1 (HPS-7).","date":"2022","source":"Frontiers in pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/35126127","citation_count":10,"is_preprint":false},{"pmid":"36672886","id":"PMC_36672886","title":"Report of Hermansky-Pudlak Syndrome in Two Families with Novel Variants in HPS3 and HPS4 Genes.","date":"2023","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/36672886","citation_count":10,"is_preprint":false},{"pmid":"38007062","id":"PMC_38007062","title":"Targeted long-read sequencing identifies and characterizes structural variants in cases of inherited platelet disorders.","date":"2023","source":"Journal of thrombosis and haemostasis : JTH","url":"https://pubmed.ncbi.nlm.nih.gov/38007062","citation_count":9,"is_preprint":false},{"pmid":"31619213","id":"PMC_31619213","title":"Novel genetic variant of HPS1 gene in Hermansky-Pudlak syndrome with fulminant progression of pulmonary fibrosis: a case report.","date":"2019","source":"BMC pulmonary medicine","url":"https://pubmed.ncbi.nlm.nih.gov/31619213","citation_count":9,"is_preprint":false},{"pmid":"28296950","id":"PMC_28296950","title":"Cellular and molecular defects in a patient with Hermansky-Pudlak syndrome type 5.","date":"2017","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/28296950","citation_count":9,"is_preprint":false},{"pmid":"20562649","id":"PMC_20562649","title":"Newborn screening for hermansky-pudlak syndrome type 3 in Puerto Rico.","date":"2010","source":"Journal of pediatric hematology/oncology","url":"https://pubmed.ncbi.nlm.nih.gov/20562649","citation_count":8,"is_preprint":false},{"pmid":"32526956","id":"PMC_32526956","title":"Novel Brown Coat Color (Cocoa) in French Bulldogs Results from a Nonsense Variant in HPS3.","date":"2020","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/32526956","citation_count":7,"is_preprint":false},{"pmid":"24766090","id":"PMC_24766090","title":"Ocular Findings in Patients with the Hermansky-Pudlak Syndrome (Types 1 and 3).","date":"2014","source":"Ophthalmic genetics","url":"https://pubmed.ncbi.nlm.nih.gov/24766090","citation_count":7,"is_preprint":false},{"pmid":"37389831","id":"PMC_37389831","title":"High-throughput microfluidic blood testing to phenotype genetically linked platelet disorders: an aid to diagnosis.","date":"2023","source":"Blood advances","url":"https://pubmed.ncbi.nlm.nih.gov/37389831","citation_count":5,"is_preprint":false},{"pmid":"39059394","id":"PMC_39059394","title":"Biogenesis of lysosome-related organelles complex-2 is an evolutionarily ancient proto-coatomer complex.","date":"2024","source":"Current biology : CB","url":"https://pubmed.ncbi.nlm.nih.gov/39059394","citation_count":5,"is_preprint":false},{"pmid":"30659653","id":"PMC_30659653","title":"Bleeding assessment in female patients with the Hermansky-Pudlak syndrome-A case series.","date":"2019","source":"European journal of haematology","url":"https://pubmed.ncbi.nlm.nih.gov/30659653","citation_count":4,"is_preprint":false},{"pmid":"31880485","id":"PMC_31880485","title":"Novel variant in HPS3 gene in a patient with Hermansky Pudlak syndrome (HPS) type 3.","date":"2019","source":"Platelets","url":"https://pubmed.ncbi.nlm.nih.gov/31880485","citation_count":3,"is_preprint":false},{"pmid":"35488210","id":"PMC_35488210","title":"NGS-based targeted sequencing identified two novel variants in Southwestern Chinese families with oculocutaneous albinism.","date":"2022","source":"BMC genomics","url":"https://pubmed.ncbi.nlm.nih.gov/35488210","citation_count":3,"is_preprint":false},{"pmid":"11592818","id":"PMC_11592818","title":"Characterization of the murine gene corresponding to human Hermansky-Pudlak syndrome type 3: exclusion of the Subtle gray (sut) locus.","date":"2001","source":"Molecular genetics and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/11592818","citation_count":3,"is_preprint":false},{"pmid":"30138987","id":"PMC_30138987","title":"[Molecular analysis of gene mutations in eight patients with Glanzmann's thrombasthenia].","date":"2018","source":"Zhonghua yi xue za zhi","url":"https://pubmed.ncbi.nlm.nih.gov/30138987","citation_count":3,"is_preprint":false},{"pmid":"36046236","id":"PMC_36046236","title":"Oculocutaneous albinism and bleeding diathesis due to a novel deletion in the HPS3 gene.","date":"2022","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/36046236","citation_count":2,"is_preprint":false},{"pmid":"34608437","id":"PMC_34608437","title":"Whole-Exome Sequencing Identified a Novel Homozygous Frameshift Mutation of HPS3 in a Consanguineous Family with Hermansky-Pudlak Syndrome.","date":"2021","source":"BioMed research international","url":"https://pubmed.ncbi.nlm.nih.gov/34608437","citation_count":2,"is_preprint":false},{"pmid":"19523149","id":"PMC_19523149","title":"Identifying putative promoter regions of Hermansky-Pudlak syndrome genes by means of phylogenetic footprinting.","date":"2009","source":"Annals of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19523149","citation_count":2,"is_preprint":false},{"pmid":"38876249","id":"PMC_38876249","title":"Genetic screening reveals hotspot variants and prevalence rates of Hermansky-Pudlak syndrome in the Chinese population.","date":"2024","source":"Clinica chimica acta; international journal of clinical chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/38876249","citation_count":2,"is_preprint":false},{"pmid":"28824043","id":"PMC_28824043","title":"Genetic variants and phylogenetic analysis of Haemophilus parasuis (HPS) OMPP2 detected in Sichuan, China from 2013 to 2015.","date":"2017","source":"The Journal of veterinary medical science","url":"https://pubmed.ncbi.nlm.nih.gov/28824043","citation_count":2,"is_preprint":false},{"pmid":"38956930","id":"PMC_38956930","title":"Genomic analysis links the American mink Royal pastel coat phenotype to retroviral element type 1 insertion in the HPS3 gene.","date":"2024","source":"Animal genetics","url":"https://pubmed.ncbi.nlm.nih.gov/38956930","citation_count":0,"is_preprint":false},{"pmid":"41196426","id":"PMC_41196426","title":"A novel HPS3 pathogenic nonsense variant associated with Hermansky-Pudlak syndrome type 3 and a platelet dysfunction.","date":"2025","source":"Molecular biology reports","url":"https://pubmed.ncbi.nlm.nih.gov/41196426","citation_count":0,"is_preprint":false},{"pmid":"41129127","id":"PMC_41129127","title":"Exome and Genome Sequencing Reveals Novel Variants for Severe Diabetic Retinopathy in Type 1 Diabetes.","date":"2025","source":"Investigative ophthalmology & visual science","url":"https://pubmed.ncbi.nlm.nih.gov/41129127","citation_count":0,"is_preprint":false},{"pmid":"38994739","id":"PMC_38994739","title":"After an initial Hermansky-Pudlak syndrome clinical diagnosis, molecular testing reveals variants for oculocutaneous albinism type 1B: A case report.","date":"2024","source":"Molecular genetics & genomic medicine","url":"https://pubmed.ncbi.nlm.nih.gov/38994739","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":34262,"output_tokens":2998,"usd":0.073878,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":10381,"output_tokens":3166,"usd":0.065528,"stage2_stop_reason":"end_turn"},"total_usd":0.139406,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2001,\n      \"finding\": \"HPS3 was identified as a novel gene on chromosome 3q24 encoding a predicted 113.7-kD protein, with a homozygous large deletion (3904-bp founder deletion removing exon 1) causing HPS-3 disease in a genetic isolate of central Puerto Rico, implicating it in vesicle formation in specialized cells.\",\n      \"method\": \"Homozygosity mapping on pooled DNA, gene cloning, mutation analysis\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — positional cloning with mutation identification; single study but foundational gene discovery with clear disease linkage\",\n      \"pmids\": [\"11455388\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"HPS3 protein was identified as a soluble and membrane-associated protein in HeLa cells; unlike HPS4, HPS3 does NOT associate with HPS1 in the BLOC-3 complex, establishing that HPS3 functions in a distinct complex from HPS1/HPS4.\",\n      \"method\": \"Sedimentation-velocity experiments, coimmunoprecipitation from HeLa cell extracts\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal biochemical fractionation and co-IP; single lab, two orthogonal methods\",\n      \"pmids\": [\"12847290\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"HPS3, HPS5, and HPS6 proteins form a stable ~340 kDa protein complex called BLOC-2 (Biogenesis of Lysosome-related Organelles Complex-2), demonstrated by coimmunoprecipitation from HeLa cell extracts and by size-exclusion chromatography and density gradient centrifugation. BLOC-2 exists in both a soluble pool and associates with membranes as a peripheral membrane protein.\",\n      \"method\": \"Coimmunoprecipitation, size-exclusion chromatography, density gradient centrifugation\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal biochemical methods (co-IP, gel filtration, density gradient) in one study, independently replicated in mouse tissues (PMID:14718540)\",\n      \"pmids\": [\"15030569\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"In mouse tissues, Hps3, Hps5, and Hps6 proteins co-immunoprecipitate and co-sediment in a ~350 kDa complex (BLOC-2). Hps5 protein is destabilized in Hps3 and Hps6 mutant tissues, and Hps6 protein is destabilized in Hps3 and Hps5 mutant tissues, indicating mutual stabilization within BLOC-2. Genetic epistasis (double-mutant mice with identical phenotypes to single mutants) confirms they act within the same pathway for vesicle trafficking to lysosome-related organelles.\",\n      \"method\": \"Coimmunoprecipitation, sucrose gradient sedimentation, gel filtration, Western blot of mutant mouse tissues, double-mutant genetic epistasis analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (co-IP, sedimentation, genetic epistasis) in mouse in vivo system, corroborating cell-line data from PMID:15030569\",\n      \"pmids\": [\"14718540\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"HPS3 associates with clathrin via a functional clathrin-binding motif (LLDFE at residues 172–176). Clathrin was co-immunoprecipitated by HPS3 antibodies from normal but not HPS3-null melanocytes. GFP-HPS3 co-localizes with clathrin on small vesicles in the perinuclear region during a 20°C temperature block, while a GFP-HPS3 clathrin-binding-domain deletion mutant (GFP-HPS3-delCBD) fails to co-localize with clathrin and shows a largely cytoplasmic distribution.\",\n      \"method\": \"Coimmunoprecipitation from melanocytes, live-cell fluorescence microscopy with temperature block, immunoelectron microscopy, domain deletion mutagenesis\",\n      \"journal\": \"BMC cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — co-IP, immunoEM, and domain-deletion mutagenesis in the same study with appropriate null-cell controls\",\n      \"pmids\": [\"16159387\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"In HPS-3 patient melanocytes, a specific subset of melanocyte proteins — tyrosinase, Tyrp1, Dct, LAMP1, and LAMP3 — show aberrant fine, floccular (rather than coarse granular) distribution, while Silver/Pmel17, Melan-A/MART-1, LAMP2, Rab27, transferrin, c-Kit, adaptin-3, and HPS1 protein localization appears normal, indicating HPS3 selectively controls trafficking of a subset of melanocyte cargo proteins.\",\n      \"method\": \"Immunocytochemistry and confocal microscopy on patient-derived melanocytes, ultrastructural analysis, DOPA histochemistry\",\n      \"journal\": \"The American journal of pathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct protein localization with patient-derived null cells and multiple cargo markers; single lab\",\n      \"pmids\": [\"15632015\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"In HPS-3 and HPS-1 patient melanocytes, tyrosinase, Tyrp1, and Dct/Tyrp2 are atypically distributed, whereas in HPS-2 melanocytes only tyrosinase shows atypical distribution. In HPS-3 melanocytes, LAMP1 and LAMP3 show a distinct less granular, more floccular pattern; HPS3 melanocytes express normal HPS1 and AP3B1 proteins.\",\n      \"method\": \"Immunofluorescence microscopy on patient-derived melanocytes, Western blot\",\n      \"journal\": \"The Journal of investigative dermatology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — comparative immunofluorescence across three HPS patient genotypes; single lab with multiple markers\",\n      \"pmids\": [\"15675963\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Functional deletion of HPS3 (HPS3−/− mice) markedly reduces platelet dense-granule secretion without affecting platelet counts, platelet morphology, alpha-granule number, or maximal P-selectin secretion. HPS3-deficient mice show significantly reduced capacity to form platelet-leukocyte aggregates, and are completely resistant to thrombotic arterial occlusion after FeCl3 injury, demonstrating HPS3's specific role in dense-granule biogenesis/secretion.\",\n      \"method\": \"Mouse knockout model, platelet function assays, flow cytometry, in vivo carotid artery thrombosis model\",\n      \"journal\": \"Circulation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean KO with defined cellular and in vivo phenotypes; multiple orthogonal assays establishing HPS3's specific role in dense-granule secretion\",\n      \"pmids\": [\"19687360\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"In zebrafish, an Hps5 missense mutation (hps5I76N) within the N-terminal WD40 repeat domain disrupts melanosome biogenesis; in vitro coexpression assays show that Hps5I76N retains the ability to bind its BLOC-2 complex partners Hps3 and Hps6, but the mutual stabilization between Hps5 and Hps6 is disrupted by this allele, establishing that the WD40 domain of Hps5 is important for inter-subunit stabilization within BLOC-2.\",\n      \"method\": \"In vitro coexpression binding assay, Western blot for protein stability, zebrafish genetic model\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro coexpression with mutagenesis and zebrafish in vivo model; single lab\",\n      \"pmids\": [\"23893484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"In Chinese HPS patients with mutations in HPS3 (as well as HPS5, HPS6), the respective partner subunits of BLOC-2 are destabilized, confirming that BLOC-2 integrity depends on all its subunits including HPS3.\",\n      \"method\": \"Western blot of patient-derived cells after NGS-identified mutations\",\n      \"journal\": \"Pigment cell & melanoma research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct protein stability assessment in patient cells; independent replication of complex-stability finding from earlier mouse and cell-line studies\",\n      \"pmids\": [\"30387913\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"BLOC-2 (containing HPS3, HPS5, HPS6 and a fourth Claret-ortholog subunit) is recruited to endolysosomes via its HPS3 subunit in Dictyostelium. In BLOC-2 mutants, WASH complex recruitment is inefficient, causing failure of lysosome maturation. Structural modeling suggests all four BLOC-2 subunits are proto-coatomer proteins, indicating BLOC-2 acts as a coat-like complex at endolysosomes.\",\n      \"method\": \"Dictyostelium genetic mutant analysis, WASH localization imaging, structural homology modeling, live-cell imaging of BLOC-2 compartment localization\",\n      \"journal\": \"Current biology : CB\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic mutant analysis with localization imaging and structural modeling; single study in a non-mammalian model organism with functional validation\",\n      \"pmids\": [\"39059394\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"HPS3 is a subunit of BLOC-2 (Biogenesis of Lysosome-related Organelles Complex-2), a ~340 kDa peripheral membrane complex also containing HPS5 and HPS6, in which HPS3 is required for complex integrity and mutual stabilization of subunits; HPS3 localizes to perinuclear clathrin-containing vesicles via a direct clathrin-binding motif (LLDFE), is recruited to endolysosomes where it facilitates WASH complex recruitment and lysosome maturation, and is specifically required for the trafficking of tyrosinase, Tyrp1, Dct, and LAMP1/3 to melanosomes in melanocytes and for platelet dense-granule biogenesis/secretion.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"HPS3 is a subunit of BLOC-2, a stable ~340 kDa peripheral membrane complex it forms with HPS5 and HPS6 that directs cargo trafficking to lysosome-related organelles [#2, #3]. HPS3 functions in a complex distinct from the HPS1/HPS4-containing BLOC-3, with which it does not associate [#1]. Within BLOC-2, the subunits are mutually stabilizing: loss of HPS3 destabilizes HPS5 and HPS6 in both mouse tissues and human patient cells, establishing that complex integrity depends on all subunits [#3, #9]. HPS3 carries a functional clathrin-binding motif (LLDFE, residues 172–176) through which it associates with clathrin on perinuclear vesicles, and deletion of this motif abolishes clathrin co-localization and renders the protein cytoplasmic [#4]. Functionally, HPS3 selectively controls trafficking of a defined subset of melanocyte cargo — tyrosinase, Tyrp1, Dct, and LAMP1/LAMP3 — to melanosomes, with other melanosomal and endosomal markers unaffected [#5, #6], and is independently required for platelet dense-granule biogenesis and secretion, such that its loss in mice abolishes dense-granule-dependent thrombus formation [#7]. At endolysosomes, the HPS3 subunit recruits BLOC-2 to the compartment where it promotes WASH complex recruitment and lysosome maturation [#10]. Loss-of-function mutation of HPS3 causes Hermansky-Pudlak syndrome type 3 [#0].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Established HPS3 as a disease gene by linking a founder deletion to a distinct form of Hermansky-Pudlak syndrome, implicating it in vesicle formation in specialized cells.\",\n      \"evidence\": \"Homozygosity mapping and positional cloning with mutation analysis in a Puerto Rican genetic isolate\",\n      \"pmids\": [\"11455388\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No molecular function or interacting partners defined\", \"Cell-type-specific trafficking role not yet demonstrated\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Resolved which complex HPS3 belongs to by showing it does not associate with HPS1, distinguishing its pathway from the BLOC-3 (HPS1/HPS4) complex.\",\n      \"evidence\": \"Sedimentation-velocity fractionation and co-immunoprecipitation from HeLa cell extracts\",\n      \"pmids\": [\"12847290\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not identify HPS3's own complex partners\", \"Membrane association unexplained\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Defined the BLOC-2 complex by demonstrating that HPS3, HPS5, and HPS6 assemble into a single ~340 kDa peripheral membrane complex with mutually dependent subunit stability.\",\n      \"evidence\": \"Co-IP, size-exclusion chromatography, and density gradient centrifugation in HeLa cells, plus mouse tissue co-sedimentation and double-mutant epistasis\",\n      \"pmids\": [\"15030569\", \"14718540\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and architecture not resolved\", \"Molecular activity of the complex undefined\", \"Membrane recruitment mechanism unknown\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Provided a mechanistic link to membrane trafficking machinery by identifying a functional clathrin-binding motif in HPS3 mediating localization to perinuclear clathrin-coated vesicles.\",\n      \"evidence\": \"Co-IP from melanocytes, temperature-block live-cell imaging, immunoEM, and clathrin-binding-domain deletion mutagenesis\",\n      \"pmids\": [\"16159387\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of clathrin binding for cargo sorting not directly tested\", \"Whether other BLOC-2 subunits also engage clathrin unknown\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Defined the cargo specificity of HPS3 by showing it selectively controls melanosomal delivery of a defined subset of proteins while sparing other markers.\",\n      \"evidence\": \"Immunocytochemistry, confocal and ultrastructural analysis of HPS-3 patient-derived melanocytes across multiple cargo markers, including comparison with HPS-1 and HPS-2\",\n      \"pmids\": [\"15632015\", \"15675963\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism distinguishing affected from unaffected cargo not established\", \"Direct cargo recognition by BLOC-2 not demonstrated\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Demonstrated a second physiological role beyond pigmentation by showing HPS3 is specifically required for platelet dense-granule biogenesis and secretion-dependent thrombosis.\",\n      \"evidence\": \"HPS3-knockout mouse platelet function assays, flow cytometry, and in vivo FeCl3 arterial thrombosis model\",\n      \"pmids\": [\"19687360\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular step within dense-granule biogenesis controlled by HPS3 not pinpointed\", \"Whether the clathrin/BLOC-2 mechanism operates identically in platelets unaddressed\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Localized the inter-subunit stabilization function within BLOC-2 to the HPS5 WD40 domain, refining how complex integrity is maintained while confirming HPS3-HPS5-HPS6 binding.\",\n      \"evidence\": \"In vitro coexpression binding/stability assays with an HPS5 WD40 missense allele and a zebrafish melanosome-biogenesis model\",\n      \"pmids\": [\"23893484\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"HPS3's own contribution to stabilization not mapped to a domain\", \"Structural basis of the complex still unresolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Confirmed in human patients that BLOC-2 integrity depends on all subunits, including HPS3, generalizing the mutual-stabilization model across species.\",\n      \"evidence\": \"Western blot of partner subunit levels in HPS3/HPS5/HPS6-mutant patient cells identified by NGS\",\n      \"pmids\": [\"30387913\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Does not add mechanistic detail beyond stability dependence\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Elucidated a coat-like mechanism by which BLOC-2 is recruited to endolysosomes through HPS3 to drive WASH recruitment and lysosome maturation.\",\n      \"evidence\": \"Dictyostelium genetic mutant analysis, WASH localization imaging, live-cell BLOC-2 compartment imaging, and proto-coatomer structural homology modeling\",\n      \"pmids\": [\"39059394\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Proto-coatomer model is structural prediction, not experimental structure\", \"Mechanism of HPS3-mediated endolysosome recruitment not defined at residue level\", \"Conservation of the WASH-recruitment role in mammalian melanocytes/platelets untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How BLOC-2 recognizes its specific cargo subset and the precise molecular activity (coat versus tether versus adaptor) HPS3 contributes at endolysosomal membranes remain undefined.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No experimental structure of BLOC-2 or HPS3\", \"Direct cargo-recognition mechanism unproven\", \"Biochemical activity of HPS3 not assigned\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [4, 10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [4]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [2, 4]},\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [10]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [10]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [2, 5]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [5, 10]}\n    ],\n    \"complexes\": [\"BLOC-2\"],\n    \"partners\": [\"HPS5\", \"HPS6\", \"CLTC\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":7,"faith_pct":85.71428571428571}}