{"gene":"ARMC3","run_date":"2026-04-28T17:12:37","timeline":{"discoveries":[{"year":2021,"finding":"Mouse ARMC3 was identified as the functional homolog of yeast Vac8; its ARM domains recruit class III phosphatidylinositol 3-kinase complex I (PtdIns3K-CI) to the phagophore assembly site (PAS) to initiate autophagosome formation, and deletion of Armc3 in mice blocked ribophagy in spermatids, causing low mitochondrial energy levels, immotile flagella, and male infertility.","method":"Mouse Armc3 knockout, functional complementation with yeast Vac8 assays, autophagy flux assays, electron microscopy of spermatids","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 — KO mouse with defined cellular phenotype (ribophagy block, infertility) and pathway placement via conservation with yeast Vac8; single lab study","pmids":["34705610"],"is_preprint":false},{"year":2016,"finding":"A frameshift mutation in bovine ARMC3 (p.A451fs26) causing premature translation termination and loss of 46% of the protein including C-terminal domains was causally associated with a tail stump sperm defect characterized by severely disorganized, immotile spermatozoa tails, establishing ARMC3 as required for normal sperm tail/flagellar structure.","method":"Homozygosity mapping, whole-genome re-sequencing, genotyping of affected vs. unaffected bulls, morphological analysis of spermatozoa","journal":"BMC genetics","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function variant with specific morphological phenotype in a mammalian model; causal link supported by genetic segregation but no direct molecular mechanism assay","pmids":["26923438"],"is_preprint":false},{"year":2024,"finding":"A homozygous ARMC3 splicing variant (c.916+1G>A) causing exon 8 skipping and a predicted truncated protein (p.Glu245_Asp305delfs*16) abolishes ARMC3 protein expression in sperm (confirmed by Western blot), leading to reduced sperm motility and disrupted flagellar ultrastructure including vacuolation of sperm mitochondria at the midpiece.","method":"Whole-exome sequencing, RT-PCR, Western blot of patient sperm, transmission electron microscopy of sperm ultrastructure","journal":"Clinical genetics","confidence":"Medium","confidence_rationale":"Tier 2 — protein-level confirmation of loss of function with ultrastructural phenotype in human patients; single family but orthogonal methods","pmids":["39221575"],"is_preprint":false},{"year":2006,"finding":"Human ARMC3 produces at least two splice variants (ARMC3_v1 and ARMC3_v2) with distinct tissue expression patterns; ARMC3_v2 encodes a 688-amino acid protein containing three ARM domains, expressed in skeletal muscle, liver, spleen, and thymus, while ARMC3_v1 is expressed in skeletal muscle, lung, prostate, and testis.","method":"cDNA cloning from human fetal brain, RT-PCR across human tissues","journal":"Genetika","confidence":"Low","confidence_rationale":"Tier 3 — cloning and expression mapping only, no functional assay","pmids":["16915934"],"is_preprint":false},{"year":2022,"finding":"A homozygous splice site variant in human ARMC3 (c.916+1G>A) causing exon 8 skipping was identified as causing non-syndromic stuttering in a consanguineous Pakistani family, expanding ARMC3's role to neurodevelopmental function.","method":"Whole-exome sequencing, segregation analysis in consanguineous family, splice prediction","journal":"Genes","confidence":"Low","confidence_rationale":"Tier 3 — genetic association with neurodevelopmental phenotype, no direct molecular mechanism demonstrated for ARMC3 in neurons","pmids":["36553564"],"is_preprint":false}],"current_model":"ARMC3 is an armadillo repeat-containing protein required for sperm flagellar integrity and male fertility; in mice, it functions as the mammalian ortholog of yeast Vac8 and promotes autophagy initiation (including ribophagy in spermatids) by recruiting class III PI3-kinase complex I to the phagophore assembly site via its ARM domains, while loss-of-function mutations in humans and cattle cause asthenozoospermia with disorganized flagellar ultrastructure, and a splice variant has also been linked to non-syndromic stuttering."},"narrative":{"teleology":[{"year":2006,"claim":"Before any functional data existed, cloning of human ARMC3 established that it encodes an ARM-domain-containing protein with multiple splice variants showing broad tissue expression including testis, resolving its basic gene structure.","evidence":"cDNA cloning from human fetal brain and RT-PCR across human tissues","pmids":["16915934"],"confidence":"Low","gaps":["No functional assay performed; expression data alone","Protein-protein interactions unknown","No disease or phenotypic link established"]},{"year":2016,"claim":"A bovine frameshift mutation truncating ARMC3 by ~46% was causally linked to a tail stump sperm defect, providing the first evidence that ARMC3 is required for sperm flagellar integrity and male fertility.","evidence":"Homozygosity mapping, whole-genome re-sequencing, genotyping segregation, and spermatozoa morphological analysis in affected bulls","pmids":["26923438"],"confidence":"Medium","gaps":["No direct molecular mechanism explaining how ARMC3 loss disorganizes flagella","Functional rescue experiment not performed","Whether ARMC3 acts cell-autonomously in spermatids not determined"]},{"year":2021,"claim":"Identification of ARMC3 as the mammalian Vac8 ortholog resolved the mechanistic question of how ARMC3 supports spermatogenesis: its ARM domains recruit PtdIns3K-CI to the phagophore assembly site to initiate autophagy, and its deletion blocks ribophagy in spermatids, explaining mitochondrial energy failure and flagellar immotility.","evidence":"Armc3 knockout mice, functional complementation with yeast Vac8, autophagy flux assays, and electron microscopy of spermatids","pmids":["34705610"],"confidence":"Medium","gaps":["Single-lab study; independent replication needed","Structural basis of ARMC3-PtdIns3K-CI interaction not resolved","Whether ARMC3 mediates autophagy outside spermatids (e.g., somatic tissues) not tested"]},{"year":2022,"claim":"A splice site variant in human ARMC3 was linked to non-syndromic stuttering, raising the question of whether ARMC3 has a neurodevelopmental role beyond spermatogenesis.","evidence":"Whole-exome sequencing and segregation analysis in a consanguineous Pakistani family","pmids":["36553564"],"confidence":"Low","gaps":["No neuronal mechanism demonstrated; genetic association only in a single family","Same splice variant later confirmed to abolish ARMC3 protein in sperm but neuronal expression/function not assessed","No replication cohort for the stuttering phenotype"]},{"year":2024,"claim":"Protein-level confirmation in human sperm that the c.916+1G>A splice variant abolishes ARMC3 expression and causes flagellar ultrastructural defects with mitochondrial vacuolation validated the bovine and mouse findings in humans, establishing ARMC3 loss-of-function as a cause of human asthenozoospermia.","evidence":"Whole-exome sequencing, RT-PCR, Western blot on patient sperm, and transmission electron microscopy","pmids":["39221575"],"confidence":"Medium","gaps":["Single family; larger cohort studies needed to establish population-level relevance","Whether autophagy/ribophagy defect underlies the human flagellar phenotype not directly tested","Functional rescue not attempted"]},{"year":null,"claim":"Key unresolved questions include the structural basis of ARMC3–PtdIns3K-CI interaction, whether ARMC3-mediated autophagy operates in somatic tissues, and whether the neurodevelopmental association with stuttering reflects a genuine ARMC3 function or a coincidental variant in a single pedigree.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural or biophysical characterization of ARMC3-PtdIns3K-CI binding","Somatic autophagy role untested in vivo","Neuronal expression and function of ARMC3 uncharacterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[0]},{"term_id":"R-HSA-1474165","term_label":"Reproduction","supporting_discovery_ids":[0,1,2]}],"complexes":[],"partners":["PIK3C3","BECN1"],"other_free_text":[]},"mechanistic_narrative":"ARMC3 is an armadillo repeat-containing protein that functions as the mammalian ortholog of yeast Vac8, recruiting class III phosphatidylinositol 3-kinase complex I (PtdIns3K-CI) to the phagophore assembly site via its ARM domains to initiate autophagosome formation; in spermatids, this activity is essential for ribophagy, and its loss causes mitochondrial energy failure, immotile flagella, and male infertility [PMID:34705610]. Loss-of-function mutations in bovine and human ARMC3 produce severely disorganized sperm flagellar ultrastructure with vacuolated midpiece mitochondria, establishing ARMC3 as required for normal sperm tail assembly and motility across mammals [PMID:26923438, PMID:39221575]. A homozygous splice site variant in ARMC3 has also been linked to non-syndromic stuttering in a human family, although no neuronal mechanism has been demonstrated [PMID:36553564]."},"prefetch_data":{"uniprot":{"accession":"Q5W041","full_name":"Armadillo repeat-containing protein 3","aliases":["Beta-catenin-like protein","Cancer/testis antigen 81","CT81","KU-CT-1"],"length_aa":872,"mass_kda":96.4,"function":"Essential for male fertility and sperm motility (By similarity). During spermatogenesis, promotes the autophagic degradation of excessive ribosomes, providing energy resources for mitochondria and thus ensuring sperm flagellar motility (PubMed:34428398)","subcellular_location":"","url":"https://www.uniprot.org/uniprotkb/Q5W041/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ARMC3","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ARMC3","total_profiled":1310},"omim":[{"mim_id":"611226","title":"ARMADILLO REPEAT-CONTAINING PROTEIN 3; ARMC3","url":"https://www.omim.org/entry/611226"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"choroid plexus","ntpm":48.7},{"tissue":"fallopian tube","ntpm":41.9},{"tissue":"testis","ntpm":31.4}],"url":"https://www.proteinatlas.org/search/ARMC3"},"hgnc":{"alias_symbol":["FLJ32827","CT81","VAC8"],"prev_symbol":[]},"alphafold":{"accession":"Q5W041","domains":[{"cath_id":"1.25.10.10","chopping":"446-551","consensus_level":"medium","plddt":95.5454,"start":446,"end":551},{"cath_id":"-","chopping":"602-608_718-872","consensus_level":"high","plddt":90.2962,"start":602,"end":872}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q5W041","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q5W041-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q5W041-F1-predicted_aligned_error_v6.png","plddt_mean":84.81},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ARMC3","jax_strain_url":"https://www.jax.org/strain/search?query=ARMC3"},"sequence":{"accession":"Q5W041","fasta_url":"https://rest.uniprot.org/uniprotkb/Q5W041.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q5W041/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q5W041"}},"corpus_meta":[{"pmid":"9664035","id":"PMC_9664035","title":"YEB3/VAC8 encodes a myristylated armadillo protein of the Saccharomyces cerevisiae vacuolar membrane that functions in vacuole fusion and inheritance.","date":"1998","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/9664035","citation_count":65,"is_preprint":false},{"pmid":"16301533","id":"PMC_16301533","title":"The DHHC protein Pfa3 affects vacuole-associated palmitoylation of the fusion factor Vac8.","date":"2005","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/16301533","citation_count":51,"is_preprint":false},{"pmid":"19416974","id":"PMC_19416974","title":"Molecular recognition of the palmitoylation substrate Vac8 by its palmitoyltransferase Pfa3.","date":"2009","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19416974","citation_count":45,"is_preprint":false},{"pmid":"16720644","id":"PMC_16720644","title":"Palmitoylation determines the function of Vac8 at the yeast vacuole.","date":"2006","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/16720644","citation_count":43,"is_preprint":false},{"pmid":"26923438","id":"PMC_26923438","title":"A frameshift mutation in ARMC3 is associated with a tail stump sperm defect in Swedish Red (Bos taurus) cattle.","date":"2016","source":"BMC genetics","url":"https://pubmed.ncbi.nlm.nih.gov/26923438","citation_count":34,"is_preprint":false},{"pmid":"32508216","id":"PMC_32508216","title":"Vac8 determines phagophore assembly site vacuolar localization during nitrogen starvation-induced autophagy.","date":"2020","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/32508216","citation_count":27,"is_preprint":false},{"pmid":"37436710","id":"PMC_37436710","title":"The Atg1 complex, Atg9, and Vac8 recruit PI3K complex I to the pre-autophagosomal structure.","date":"2023","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/37436710","citation_count":26,"is_preprint":false},{"pmid":"16467476","id":"PMC_16467476","title":"Candida albicans VAC8 is required for vacuolar inheritance and normal hyphal branching.","date":"2006","source":"Eukaryotic cell","url":"https://pubmed.ncbi.nlm.nih.gov/16467476","citation_count":25,"is_preprint":false},{"pmid":"16874085","id":"PMC_16874085","title":"Role of Vac8 in formation of the vacuolar sequestering membrane during micropexophagy.","date":"2006","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/16874085","citation_count":24,"is_preprint":false},{"pmid":"31512555","id":"PMC_31512555","title":"Quaternary structures of Vac8 differentially regulate the Cvt and PMN pathways.","date":"2019","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/31512555","citation_count":20,"is_preprint":false},{"pmid":"15701652","id":"PMC_15701652","title":"ATP-independent control of Vac8 palmitoylation by a SNARE subcomplex on yeast vacuoles.","date":"2005","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/15701652","citation_count":19,"is_preprint":false},{"pmid":"31352862","id":"PMC_31352862","title":"The carboxy terminus of yeast Atg13 binds phospholipid membrane via motifs that overlap with the Vac8-interacting domain.","date":"2019","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/31352862","citation_count":16,"is_preprint":false},{"pmid":"16921262","id":"PMC_16921262","title":"Early and late molecular events of glucose-induced pexophagy in Pichia pastoris require Vac8.","date":"2006","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/16921262","citation_count":16,"is_preprint":false},{"pmid":"37313373","id":"PMC_37313373","title":"Chemical Complementarity of Breast Cancer Resident, T-Cell Receptor CDR3 Domains and the Cancer Antigen, ARMC3, is Associated With Higher Levels of Survival and Granzyme Expression.","date":"2023","source":"Cancer informatics","url":"https://pubmed.ncbi.nlm.nih.gov/37313373","citation_count":13,"is_preprint":false},{"pmid":"31262095","id":"PMC_31262095","title":"Vac8 Controls Vacuolar Membrane Dynamics during Different Autophagy Pathways in Saccharomyces cerevisiae.","date":"2019","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/31262095","citation_count":13,"is_preprint":false},{"pmid":"34705610","id":"PMC_34705610","title":"A conserved Vac8/ARMC3-PtdIns3K-CI cascade regulates autophagy initiation and functions in spermiogenesis by promoting ribophagy.","date":"2021","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/34705610","citation_count":10,"is_preprint":false},{"pmid":"39221575","id":"PMC_39221575","title":"A homozygous ARMC3 splicing variant causes asthenozoospermia and flagellar disorganization in a consanguineous family.","date":"2024","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/39221575","citation_count":10,"is_preprint":false},{"pmid":"37094131","id":"PMC_37094131","title":"Structures of Vac8-containing protein complexes reveal the underlying mechanism by which Vac8 regulates multiple cellular processes.","date":"2023","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/37094131","citation_count":7,"is_preprint":false},{"pmid":"36553564","id":"PMC_36553564","title":"The Expansion of the Spectrum in Stuttering Disorders to a Novel ARMC Gene Family (ARMC3).","date":"2022","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/36553564","citation_count":6,"is_preprint":false},{"pmid":"16915934","id":"PMC_16915934","title":"Cloning and expression of ARMC3_v2, a novel splicing variant of the human ARMC3 gene.","date":"2006","source":"Genetika","url":"https://pubmed.ncbi.nlm.nih.gov/16915934","citation_count":3,"is_preprint":false},{"pmid":"39045779","id":"PMC_39045779","title":"The emerging significance of Vac8, a multi-purpose armadillo-repeat protein in yeast.","date":"2024","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/39045779","citation_count":2,"is_preprint":false},{"pmid":"40661350","id":"PMC_40661350","title":"The vacuolar protein 8 (Vac8) homolog in Cryptococcus neoformans plays conserved and unique roles in vacuolar and cellular morphology, impacting important stress responses and virulence traits.","date":"2025","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/40661350","citation_count":0,"is_preprint":false},{"pmid":"37465006","id":"PMC_37465006","title":"Erratum to \"Chemical Complementarity of Breast Cancer Resident, T-Cell Receptor CDR3 Domains and the Cancer Antigen, ARMC3, is Associated With Higher Levels of Survival and Granzyme Expression\".","date":"2023","source":"Cancer informatics","url":"https://pubmed.ncbi.nlm.nih.gov/37465006","citation_count":0,"is_preprint":false},{"pmid":"41440702","id":"PMC_41440702","title":"The Vacuolar Protein 8 (Vac8) Homolog in Cryptococcus neoformans Impacts Stress Responses and Virulence Traits Through Conserved and Unique Roles.","date":"2025","source":"Journal of fungi (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/41440702","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.05.22.655601","title":"The vacuolar protein 8 (Vac8) homolog in <i>Cryptococcus neoformans</i> plays conserved and unique roles in vacuolar and cellular morphology, impacting important stress responses and virulence traits","date":"2025-05-22","source":"bioRxiv","url":"https://doi.org/10.1101/2025.05.22.655601","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.03.24.645041","title":"Cargo adaptors use a handhold mechanism to engage with myosin V for organelle transport","date":"2025-03-25","source":"bioRxiv","url":"https://doi.org/10.1101/2025.03.24.645041","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13437,"output_tokens":1744,"usd":0.033236},"stage2":{"model":"claude-opus-4-6","input_tokens":4532,"output_tokens":1666,"usd":0.096465},"total_usd":0.129701,"stage1_batch_id":"msgbatch_01TqNM6p6FsoMBT2jzQTwKBr","stage2_batch_id":"msgbatch_01Ya473eco8sTHbvRymQaU8o","note":"batch pricing = 50% of standard"},"stage1_raw":"Looking at the corpus, I need to identify papers about human/mammalian ARMC3. Most papers here are about yeast Vac8, which the corpus explicitly identifies as a homolog/ortholog of mouse ARMC3 in one key paper (PMID:34705610). Let me assess:\n\n- Papers 1-13, 15, 18, 21, 22, 24, 25, 26: About yeast Vac8 — these are about the ortholog in a model organism (yeast), not ARMC3 directly\n- Paper 16 (PMID:34705610): Explicitly states \"mouse ARMC3 is the homolog of yeast Vac8\" and studies Armc3 deletion in mice\n- Paper 5 (PMID:26923438): Bovine ARMC3 frameshift mutation — mammalian ortholog study\n- Paper 17 (PMID:39221575): Human ARMC3 splicing variant causing asthenozoospermia\n- Paper 19 (PMID:36553564): Human ARMC3 splice site variant causing stuttering\n- Paper 20 (PMID:16915934): Cloning of human ARMC3 splice variant\n- Paper 14 (PMID:37313373): Cancer immunology/biomarker — exclude (no mechanism)\n\nThe yeast Vac8 papers describe an ortholog but the function is fundamentally different (vacuolar fusion, autophagy initiation in yeast) from what's established for mammalian ARMC3. However, paper 16 directly bridges these by establishing ARMC3 as the mammalian functional homolog and studying it in mice.\n\nI'll include findings directly about ARMC3 (mammalian/bovine) and the direct mechanistic bridge paper.\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2021,\n      \"finding\": \"Mouse ARMC3 was identified as the functional homolog of yeast Vac8; its ARM domains recruit class III phosphatidylinositol 3-kinase complex I (PtdIns3K-CI) to the phagophore assembly site (PAS) to initiate autophagosome formation, and deletion of Armc3 in mice blocked ribophagy in spermatids, causing low mitochondrial energy levels, immotile flagella, and male infertility.\",\n      \"method\": \"Mouse Armc3 knockout, functional complementation with yeast Vac8 assays, autophagy flux assays, electron microscopy of spermatids\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with defined cellular phenotype (ribophagy block, infertility) and pathway placement via conservation with yeast Vac8; single lab study\",\n      \"pmids\": [\"34705610\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"A frameshift mutation in bovine ARMC3 (p.A451fs26) causing premature translation termination and loss of 46% of the protein including C-terminal domains was causally associated with a tail stump sperm defect characterized by severely disorganized, immotile spermatozoa tails, establishing ARMC3 as required for normal sperm tail/flagellar structure.\",\n      \"method\": \"Homozygosity mapping, whole-genome re-sequencing, genotyping of affected vs. unaffected bulls, morphological analysis of spermatozoa\",\n      \"journal\": \"BMC genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function variant with specific morphological phenotype in a mammalian model; causal link supported by genetic segregation but no direct molecular mechanism assay\",\n      \"pmids\": [\"26923438\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"A homozygous ARMC3 splicing variant (c.916+1G>A) causing exon 8 skipping and a predicted truncated protein (p.Glu245_Asp305delfs*16) abolishes ARMC3 protein expression in sperm (confirmed by Western blot), leading to reduced sperm motility and disrupted flagellar ultrastructure including vacuolation of sperm mitochondria at the midpiece.\",\n      \"method\": \"Whole-exome sequencing, RT-PCR, Western blot of patient sperm, transmission electron microscopy of sperm ultrastructure\",\n      \"journal\": \"Clinical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — protein-level confirmation of loss of function with ultrastructural phenotype in human patients; single family but orthogonal methods\",\n      \"pmids\": [\"39221575\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Human ARMC3 produces at least two splice variants (ARMC3_v1 and ARMC3_v2) with distinct tissue expression patterns; ARMC3_v2 encodes a 688-amino acid protein containing three ARM domains, expressed in skeletal muscle, liver, spleen, and thymus, while ARMC3_v1 is expressed in skeletal muscle, lung, prostate, and testis.\",\n      \"method\": \"cDNA cloning from human fetal brain, RT-PCR across human tissues\",\n      \"journal\": \"Genetika\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — cloning and expression mapping only, no functional assay\",\n      \"pmids\": [\"16915934\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"A homozygous splice site variant in human ARMC3 (c.916+1G>A) causing exon 8 skipping was identified as causing non-syndromic stuttering in a consanguineous Pakistani family, expanding ARMC3's role to neurodevelopmental function.\",\n      \"method\": \"Whole-exome sequencing, segregation analysis in consanguineous family, splice prediction\",\n      \"journal\": \"Genes\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — genetic association with neurodevelopmental phenotype, no direct molecular mechanism demonstrated for ARMC3 in neurons\",\n      \"pmids\": [\"36553564\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ARMC3 is an armadillo repeat-containing protein required for sperm flagellar integrity and male fertility; in mice, it functions as the mammalian ortholog of yeast Vac8 and promotes autophagy initiation (including ribophagy in spermatids) by recruiting class III PI3-kinase complex I to the phagophore assembly site via its ARM domains, while loss-of-function mutations in humans and cattle cause asthenozoospermia with disorganized flagellar ultrastructure, and a splice variant has also been linked to non-syndromic stuttering.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ARMC3 is an armadillo repeat-containing protein that functions as the mammalian ortholog of yeast Vac8, recruiting class III phosphatidylinositol 3-kinase complex I (PtdIns3K-CI) to the phagophore assembly site via its ARM domains to initiate autophagosome formation; in spermatids, this activity is essential for ribophagy, and its loss causes mitochondrial energy failure, immotile flagella, and male infertility [PMID:34705610]. Loss-of-function mutations in bovine and human ARMC3 produce severely disorganized sperm flagellar ultrastructure with vacuolated midpiece mitochondria, establishing ARMC3 as required for normal sperm tail assembly and motility across mammals [PMID:26923438, PMID:39221575]. A homozygous splice site variant in ARMC3 has also been linked to non-syndromic stuttering in a human family, although no neuronal mechanism has been demonstrated [PMID:36553564].\",\n  \"teleology\": [\n    {\n      \"year\": 2006,\n      \"claim\": \"Before any functional data existed, cloning of human ARMC3 established that it encodes an ARM-domain-containing protein with multiple splice variants showing broad tissue expression including testis, resolving its basic gene structure.\",\n      \"evidence\": \"cDNA cloning from human fetal brain and RT-PCR across human tissues\",\n      \"pmids\": [\"16915934\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No functional assay performed; expression data alone\",\n        \"Protein-protein interactions unknown\",\n        \"No disease or phenotypic link established\"\n      ]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"A bovine frameshift mutation truncating ARMC3 by ~46% was causally linked to a tail stump sperm defect, providing the first evidence that ARMC3 is required for sperm flagellar integrity and male fertility.\",\n      \"evidence\": \"Homozygosity mapping, whole-genome re-sequencing, genotyping segregation, and spermatozoa morphological analysis in affected bulls\",\n      \"pmids\": [\"26923438\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No direct molecular mechanism explaining how ARMC3 loss disorganizes flagella\",\n        \"Functional rescue experiment not performed\",\n        \"Whether ARMC3 acts cell-autonomously in spermatids not determined\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identification of ARMC3 as the mammalian Vac8 ortholog resolved the mechanistic question of how ARMC3 supports spermatogenesis: its ARM domains recruit PtdIns3K-CI to the phagophore assembly site to initiate autophagy, and its deletion blocks ribophagy in spermatids, explaining mitochondrial energy failure and flagellar immotility.\",\n      \"evidence\": \"Armc3 knockout mice, functional complementation with yeast Vac8, autophagy flux assays, and electron microscopy of spermatids\",\n      \"pmids\": [\"34705610\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single-lab study; independent replication needed\",\n        \"Structural basis of ARMC3-PtdIns3K-CI interaction not resolved\",\n        \"Whether ARMC3 mediates autophagy outside spermatids (e.g., somatic tissues) not tested\"\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"A splice site variant in human ARMC3 was linked to non-syndromic stuttering, raising the question of whether ARMC3 has a neurodevelopmental role beyond spermatogenesis.\",\n      \"evidence\": \"Whole-exome sequencing and segregation analysis in a consanguineous Pakistani family\",\n      \"pmids\": [\"36553564\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No neuronal mechanism demonstrated; genetic association only in a single family\",\n        \"Same splice variant later confirmed to abolish ARMC3 protein in sperm but neuronal expression/function not assessed\",\n        \"No replication cohort for the stuttering phenotype\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Protein-level confirmation in human sperm that the c.916+1G>A splice variant abolishes ARMC3 expression and causes flagellar ultrastructural defects with mitochondrial vacuolation validated the bovine and mouse findings in humans, establishing ARMC3 loss-of-function as a cause of human asthenozoospermia.\",\n      \"evidence\": \"Whole-exome sequencing, RT-PCR, Western blot on patient sperm, and transmission electron microscopy\",\n      \"pmids\": [\"39221575\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single family; larger cohort studies needed to establish population-level relevance\",\n        \"Whether autophagy/ribophagy defect underlies the human flagellar phenotype not directly tested\",\n        \"Functional rescue not attempted\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of ARMC3–PtdIns3K-CI interaction, whether ARMC3-mediated autophagy operates in somatic tissues, and whether the neurodevelopmental association with stuttering reflects a genuine ARMC3 function or a coincidental variant in a single pedigree.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No structural or biophysical characterization of ARMC3-PtdIns3K-CI binding\",\n        \"Somatic autophagy role untested in vivo\",\n        \"Neuronal expression and function of ARMC3 uncharacterized\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-1474165\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"PIK3C3\",\n      \"BECN1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}