{"gene":"ACTL7A","run_date":"2026-04-28T17:12:37","timeline":{"discoveries":[{"year":1999,"finding":"ACTL7A encodes a 435-amino-acid actin-like protein (predicted molecular mass 48.6 kDa) expressed in a wide variety of adult tissues; it is an intronless gene located on chromosome 9q31 in a head-to-head orientation with ACTL7B on a common 8-kb HindIII fragment.","method":"cDNA selection, direct genomic sequencing, linkage mapping","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 — original cloning and mapping study with direct sequencing; single lab","pmids":["10373328"],"is_preprint":false},{"year":2012,"finding":"During capacitation in mouse spermatozoa, ACTL7A expression is upregulated via the PKA pathway and its localization undergoes remodeling, indicating it is an essential component of the capacitation process.","method":"Western blot and indirect immunostaining of capacitated vs. non-capacitated mouse sperm; PKA pathway analysis","journal":"Fertility and sterility","confidence":"Medium","confidence_rationale":"Tier 2 — two orthogonal methods (western blot + immunostaining) in a single lab; pathway identified via pharmacological approach","pmids":["23211711"],"is_preprint":false},{"year":2012,"finding":"Anti-ACTL7A antibodies cause agglutination of mouse and human spermatozoa in vitro and markedly reduce sperm fertilizing capacity; active immunization of mice with ACTL7A protein significantly reduces fertility, establishing ACTL7A as a target of immunologic infertility.","method":"In vitro sperm agglutination assay, fertility assay in immunized mice, mass spectrometry identification, indirect immunostaining","journal":"Fertility and sterility","confidence":"Medium","confidence_rationale":"Tier 2 — functional fertility assay with antibody treatment plus active immunization; single lab","pmids":["22386842"],"is_preprint":false},{"year":2020,"finding":"A homozygous missense mutation in ACTL7A causes acrosomal ultrastructural defects in human and mouse sperm, and results in reduced expression and abnormal localization of PLCζ in sperm, linking ACTL7A to oocyte activation competence and early embryonic arrest.","method":"Whole-exome sequencing, knock-in mouse model, transmission electron microscopy (TEM), immunofluorescence, western blot, artificial oocyte activation rescue","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (TEM, IF, WB, mouse model, functional rescue); replicated in human and mouse","pmids":["32923619"],"is_preprint":false},{"year":2021,"finding":"Compound heterozygous loss-of-function variants in ACTL7A cause ultrastructural defects in the acrosome and perinuclear theca, and significantly reduce PLCζ protein expression in sperm, leading to oocyte activation deficiency and total fertilization failure.","method":"Whole-exome sequencing, Sanger sequencing, TEM, immunofluorescence, western blotting, AOA rescue (calcium ionophore A23187)","journal":"Human reproduction (Oxford, England)","confidence":"Medium","confidence_rationale":"Tier 2 — multiple methods in single family; consistent with prior work","pmids":["34727571"],"is_preprint":false},{"year":2022,"finding":"ACTL7A forms a complex with zona pellucida binding protein (ZPBP), and loss of ACTL7A in knockout mice alters ZPBP localization in sperm, reducing sperm–zona pellucida binding ability and contributing to fertilization failure.","method":"Co-immunoprecipitation, immunofluorescence, knockout mouse model, IVF/ICSI functional assay","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP plus functional KO phenotype; single lab","pmids":["35921706"],"is_preprint":false},{"year":2022,"finding":"A pathogenic missense variant in ACTL7A (p.Gly402Ser) causes the mutant protein to fail to attach to the acroplaxome and to be discharged in cytoplasmic droplets, resulting in absence of ACTL7A in epididymal spermatozoa, acrosome detachment from the nuclear membrane (bubble-shaped acrosomes), and discharge of PLCζ, leading to total fertilization failure.","method":"Knock-in mouse model, TEM, immunofluorescence, immunoprecipitation followed by LC-MS, western blot, AOA rescue","journal":"Molecular human reproduction","confidence":"High","confidence_rationale":"Tier 1–2 — combined structural (TEM), interactome (IP-MS), functional (mouse model + rescue), multiple orthogonal methods; single lab but comprehensive","pmids":["35863052"],"is_preprint":false},{"year":2022,"finding":"A novel homozygous missense mutation (p.D75A) in ACTL7A leads to protein degradation in sperm, acrosomal ultrastructural defects and irregular perinuclear theca, and abnormal localization and reduced expression of PLCζ, causing fertilization failure after ICSI.","method":"WES, 3D structural modeling, immunofluorescence, western blot, TEM","journal":"Molecular genetics and genomics: MGG","confidence":"Medium","confidence_rationale":"Tier 2–3 — immunofluorescence + WB + TEM; structural modeling is in silico; single lab","pmids":["36574082"],"is_preprint":false},{"year":2023,"finding":"ACTL7A is dynamically localized within the nucleus and subacrosomal space in developing spermatids and later in postacrosomal regions; knockout of Actl7a causes complete loss of subacrosomal filamentous actin (F-actin) structures, indicating ACTL7A is required for acroplaxome-associated F-actin formation and acrosomal attachment integrity.","method":"Actl7a knockout mouse model, immunofluorescence (including F-actin staining), live/fixed imaging of developing spermatids","journal":"Molecular human reproduction","confidence":"High","confidence_rationale":"Tier 2 — KO mouse with defined cellular phenotype (loss of F-actin) plus dynamic localization imaging; mechanistic model supported by multiple observations","pmids":["36734600"],"is_preprint":false},{"year":2023,"finding":"Loss of ACTL7A in knockout mice causes small-head sperm due to defective acrosome-acroplaxome-manchette complex formation; proteomics revealed that ACTL7A loss activates autophagy inhibition via the PI3K/AKT/mTOR pathway, leading to PDLIM1 accumulation and hindered manchette development.","method":"Actl7a KO mouse model, immunofluorescence, TEM, tandem mass tag quantitative proteomics, western blot, ICSI-AOA rescue","journal":"Reproductive biology and endocrinology: RB&E","confidence":"Medium","confidence_rationale":"Tier 2 — KO mouse + proteomics + IF + TEM; pathway placement via proteomics inference; single lab","pmids":["37667331"],"is_preprint":false},{"year":2023,"finding":"Homozygous nonsense variant in ACTL7A causes increased thickness of the perinuclear matrix and detachment of the acrosome from the nuclear envelope as observed by TEM, further confirming ACTL7A's structural role in perinuclear theca integrity.","method":"WES, TEM, immunofluorescence","journal":"Clinical genetics","confidence":"Medium","confidence_rationale":"Tier 2–3 — TEM phenotype in human patient; consistent with multiple prior reports","pmids":["36593593"],"is_preprint":false},{"year":2024,"finding":"ACTL7A is present in the nucleus of developing spermatids; in the absence of ACTL7A, intranuclear localization of HDAC1 and HDAC3 is lost, implicating ACTL7A in chromatin regulatory complex function during spermiogenesis. In silico modeling further suggests ACTL7A can substitute for actin/ACTL6A in binding HSA domains of INO80 and SWI/SNF nucleosome remodeling complexes.","method":"Actl7a KO mouse model, immunofluorescence for HDAC1/HDAC3 nuclear localization, testis transcriptomic analysis, AI-facilitated in silico structural modeling","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3–4 — in vivo localization change is Tier 3; mechanistic model for nucleosome remodeler interaction is computational only; preprint","pmids":["38464253"],"is_preprint":true},{"year":2025,"finding":"ACTL7A interacts with the perinuclear theca protein FNDC8 and with CCIN during spermiogenesis; depletion of FNDC8 destabilizes ACTL7A protein, placing ACTL7A downstream of FNDC8 in a PT protein interaction network required for sperm head morphogenesis.","method":"Co-immunoprecipitation, Fndc8 knockout mouse model, immunofluorescence, western blot","journal":"Zoological research","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP plus KO mouse with defined phenotype; single lab","pmids":["41169243"],"is_preprint":false},{"year":2025,"finding":"ACTL7A interacts with ARPM1 (ACTRT3) as shown by co-immunoprecipitation; ARPM1 deficiency does not directly ablate ACTL7A but ACTL7A is part of the PT cytoskeletal complex that also includes ACTRT1, ACTRT2, and ZPBP.","method":"Co-immunoprecipitation from mouse testis/sperm lysates","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 — single Co-IP; preprint, no functional follow-up specific to ACTL7A","pmids":["bio_10.1101_2025.03.27.645694"],"is_preprint":true}],"current_model":"ACTL7A is a testis-enriched actin-related protein that localizes dynamically to the nucleus, subacrosomal space, and postacrosomal perinuclear theca (PT) of developing spermatids, where it is essential for acroplaxome-associated F-actin formation and acrosomal anchoring to the nuclear surface; loss-of-function mutations cause acrosomal detachment, small-head sperm via defective acrosome-acroplaxome-manchette complex, and reduced/mislocalized PLCζ, abolishing oocyte activation and causing total fertilization failure, while its expression during capacitation is upregulated through the PKA pathway and it participates in a PT protein complex with FNDC8, CCIN, ZPBP, and ARPM1."},"narrative":{"teleology":[{"year":1999,"claim":"Identification of ACTL7A as an intronless actin-related gene on chromosome 9q31, clustered with ACTL7B, established it as a novel member of the actin-related protein family expressed broadly in adult tissues.","evidence":"cDNA selection and direct genomic sequencing with linkage mapping","pmids":["10373328"],"confidence":"Medium","gaps":["No functional data; expression breadth not reconciled with later testis-enrichment findings","No protein-level characterization"]},{"year":2012,"claim":"Demonstration that ACTL7A is upregulated via the PKA pathway during capacitation and that anti-ACTL7A antibodies block fertilization established ACTL7A as a functionally important sperm surface/structural component required for fertility.","evidence":"Western blot and immunostaining of capacitated mouse sperm; in vitro agglutination assays; active immunization fertility assays in mice","pmids":["23211711","22386842"],"confidence":"Medium","gaps":["Molecular mechanism of PKA-dependent upregulation undefined","Whether antibody effects reflect surface exposure or secondary disruption unclear","No genetic loss-of-function model yet"]},{"year":2020,"claim":"A homozygous ACTL7A missense mutation in a human family, recapitulated in a knock-in mouse, linked ACTL7A directly to acrosomal ultrastructural integrity and PLCζ-dependent oocyte activation, establishing it as a cause of total fertilization failure.","evidence":"WES in infertile patient, knock-in mouse model, TEM, immunofluorescence, western blot, artificial oocyte activation rescue","pmids":["32923619"],"confidence":"High","gaps":["Mechanism by which ACTL7A controls PLCζ expression/localization unknown","Single family — allelic spectrum not yet defined"]},{"year":2021,"claim":"Identification of compound heterozygous ACTL7A variants causing the same phenotype confirmed that biallelic loss-of-function is a recurrent genetic cause of oocyte activation deficiency and fertilization failure in humans.","evidence":"WES, Sanger validation, TEM, immunofluorescence, western blot, calcium ionophore rescue in a second family","pmids":["34727571"],"confidence":"Medium","gaps":["Still limited to two families","Carrier frequency and population-level contribution unknown"]},{"year":2022,"claim":"A series of studies using knock-in/knockout mouse models and proteomics defined the precise structural role of ACTL7A: it anchors to the acroplaxome, and specific mutations (e.g., G402S) cause the protein to be discharged in cytoplasmic droplets, resulting in bubble-shaped acrosomes; ACTL7A also forms a complex with ZPBP to facilitate zona pellucida binding.","evidence":"Knock-in and knockout mouse models, TEM, IP-LC/MS interactome, Co-IP with ZPBP, IVF/ICSI functional assays","pmids":["35863052","35921706","36574082"],"confidence":"High","gaps":["Direct binding interface between ACTL7A and ZPBP uncharacterized","How ACTL7A is recruited to the acroplaxome molecularly remains unclear"]},{"year":2023,"claim":"Knockout studies revealed that ACTL7A is absolutely required for subacrosomal F-actin formation and that its loss causes small-head sperm through defective acrosome-acroplaxome-manchette complex assembly, with proteomics implicating PI3K/AKT/mTOR-mediated autophagy inhibition and PDLIM1 accumulation as downstream consequences.","evidence":"Actl7a KO mouse, F-actin staining, live/fixed imaging, TEM, TMT quantitative proteomics, western blot","pmids":["36734600","37667331","36593593"],"confidence":"High","gaps":["Whether ACTL7A directly polymerizes or nucleates F-actin is unknown","PI3K/AKT/mTOR pathway link is correlative from proteomics, not validated by pathway perturbation","PDLIM1 role in manchette development not independently confirmed"]},{"year":2025,"claim":"Identification of FNDC8 and CCIN as direct interaction partners that stabilize ACTL7A protein placed ACTL7A within a hierarchical perinuclear theca protein network required for sperm head morphogenesis.","evidence":"Co-immunoprecipitation, Fndc8 KO mouse model, immunofluorescence, western blot","pmids":["41169243"],"confidence":"Medium","gaps":["Stoichiometry and assembly order of the PT complex not defined","Whether FNDC8 stabilizes ACTL7A directly or through a scaffold is unclear"]},{"year":null,"claim":"Key unresolved questions include whether ACTL7A has intrinsic actin-like polymerization or ATPase activity, the structural basis of its integration into the acroplaxome, the mechanism by which it controls PLCζ retention in sperm, and whether it substitutes for canonical actin in nuclear chromatin-remodeling complexes during spermiogenesis.","evidence":"","pmids":[],"confidence":"Low","gaps":["No biochemical reconstitution of ACTL7A polymerization or ATPase activity","No crystal or cryo-EM structure","Chromatin remodeler interaction model is computational only","PLCζ retention mechanism completely undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[8,9,12,6]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[8,11]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[8,6,9]}],"pathway":[{"term_id":"R-HSA-1474165","term_label":"Reproduction","supporting_discovery_ids":[3,4,6,8,9]}],"complexes":["Perinuclear theca complex (FNDC8–CCIN–ACTL7A–ZPBP)"],"partners":["ZPBP","FNDC8","CCIN","PLCZ1","ARPM1"],"other_free_text":[]},"mechanistic_narrative":"ACTL7A is a testis-enriched actin-related protein essential for spermiogenesis, acrosome biogenesis, and male fertility. During spermatid development, ACTL7A localizes dynamically to the nucleus, subacrosomal space, and postacrosomal perinuclear theca, where it is required for acroplaxome-associated F-actin assembly and stable anchoring of the acrosome to the nuclear envelope; loss of ACTL7A abolishes subacrosomal F-actin structures, causes acrosomal detachment, small-head sperm morphology through defective acrosome-acroplaxome-manchette complex formation, and loss of intranuclear HDAC1/HDAC3 localization [PMID:36734600, PMID:37667331, PMID:35863052, PMID:38464253]. ACTL7A participates in a perinuclear theca protein complex with FNDC8, CCIN, ZPBP, and ARPM1, and its stability depends on FNDC8 [PMID:41169243, PMID:35921706]. Homozygous or compound heterozygous loss-of-function mutations in ACTL7A cause total fertilization failure in humans by disrupting acrosomal ultrastructure, reducing PLCζ expression and localization in sperm, and abolishing oocyte activation competence [PMID:32923619, PMID:34727571]."},"prefetch_data":{"uniprot":{"accession":"Q9Y615","full_name":"Actin-like protein 7A","aliases":["Actin-like-7-alpha"],"length_aa":435,"mass_kda":48.6,"function":"Essential for normal spermatogenesis and male fertility. Required for normal sperm head morphology, acroplaxome formation, acrosome attachment, and acrosome granule stability. May anchor and stabilize acrosomal adherence to the acroplaxome at least in part by facilitating the presence of F-actin in the subacrosomal space (By similarity). May play an important role in formation and fusion of Golgi-derived vesicles during acrosome biogenesis (PubMed:32923619)","subcellular_location":"Cytoplasm, cytoskeleton; Golgi apparatus; Cytoplasm; Nucleus; Cytoplasmic vesicle, secretory vesicle, acrosome","url":"https://www.uniprot.org/uniprotkb/Q9Y615/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ACTL7A","classification":"Not Classified","n_dependent_lines":15,"n_total_lines":1208,"dependency_fraction":0.012417218543046357},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ACTL7A","total_profiled":1310},"omim":[{"mim_id":"620500","title":"SPERMATOGENIC FAILURE 87; SPGF87","url":"https://www.omim.org/entry/620500"},{"mim_id":"620499","title":"SPERMATOGENIC FAILURE 86; SPGF86","url":"https://www.omim.org/entry/620499"},{"mim_id":"620170","title":"SPERMATOGENIC FAILURE 78; SPGF78","url":"https://www.omim.org/entry/620170"},{"mim_id":"620160","title":"IQ MOTIF-CONTAINING PROTEIN N; IQCN","url":"https://www.omim.org/entry/620160"},{"mim_id":"619251","title":"ACTIN-LIKE 9; ACTL9","url":"https://www.omim.org/entry/619251"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Perinuclear theca","reliability":"Supported"}],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in single","driving_tissues":[{"tissue":"testis","ntpm":218.7}],"url":"https://www.proteinatlas.org/search/ACTL7A"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q9Y615","domains":[{"cath_id":"3.30.420.40","chopping":"73-209_397-435","consensus_level":"medium","plddt":90.5615,"start":73,"end":435},{"cath_id":"3.90.640.10","chopping":"247-329","consensus_level":"high","plddt":94.5358,"start":247,"end":329}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y615","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y615-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y615-F1-predicted_aligned_error_v6.png","plddt_mean":84.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ACTL7A","jax_strain_url":"https://www.jax.org/strain/search?query=ACTL7A"},"sequence":{"accession":"Q9Y615","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9Y615.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9Y615/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y615"}},"corpus_meta":[{"pmid":"32923619","id":"PMC_32923619","title":"Disruption in ACTL7A causes acrosomal ultrastructural defects in human and mouse sperm as a novel male factor inducing early embryonic arrest.","date":"2020","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/32923619","citation_count":78,"is_preprint":false},{"pmid":"34727571","id":"PMC_34727571","title":"Novel bi-allelic variants in ACTL7A are associated with male infertility and total fertilization failure.","date":"2021","source":"Human reproduction (Oxford, England)","url":"https://pubmed.ncbi.nlm.nih.gov/34727571","citation_count":34,"is_preprint":false},{"pmid":"10373328","id":"PMC_10373328","title":"Cloning, mapping, and expression of two novel actin genes, actin-like-7A (ACTL7A) and actin-like-7B (ACTL7B), from the familial dysautonomia candidate region on 9q31.","date":"1999","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/10373328","citation_count":30,"is_preprint":false},{"pmid":"35863052","id":"PMC_35863052","title":"Pathogenic variant in ACTL7A causes severe teratozoospermia characterized by bubble-shaped acrosomes and male infertility.","date":"2022","source":"Molecular human reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/35863052","citation_count":21,"is_preprint":false},{"pmid":"36734600","id":"PMC_36734600","title":"Testis-specific actin-like 7A (ACTL7A) is an indispensable protein for subacrosomal-associated F-actin formation, acrosomal anchoring, and male fertility.","date":"2023","source":"Molecular human reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/36734600","citation_count":21,"is_preprint":false},{"pmid":"36593593","id":"PMC_36593593","title":"Novel variants in ACTL7A and PLCZ1 are associated with male infertility and total fertilization failure.","date":"2023","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/36593593","citation_count":17,"is_preprint":false},{"pmid":"22386842","id":"PMC_22386842","title":"Anti-ACTL7a antibodies: a cause of infertility.","date":"2012","source":"Fertility and sterility","url":"https://pubmed.ncbi.nlm.nih.gov/22386842","citation_count":16,"is_preprint":false},{"pmid":"37667331","id":"PMC_37667331","title":"Loss of ACTL7A causes small head sperm by defective acrosome-acroplaxome-manchette complex.","date":"2023","source":"Reproductive biology and endocrinology : RB&E","url":"https://pubmed.ncbi.nlm.nih.gov/37667331","citation_count":15,"is_preprint":false},{"pmid":"35921706","id":"PMC_35921706","title":"Actl7a deficiency in mice leads to male infertility and fertilization failure.","date":"2022","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/35921706","citation_count":13,"is_preprint":false},{"pmid":"26957350","id":"PMC_26957350","title":"Immune Infertility Should Be Positively Diagnosed Using an Accurate Method by Monitoring the Level of Anti-ACTL7a Antibody.","date":"2016","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/26957350","citation_count":12,"is_preprint":false},{"pmid":"36574082","id":"PMC_36574082","title":"A novel homozygous mutation in ACTL7A leads to male infertility.","date":"2022","source":"Molecular genetics and genomics : MGG","url":"https://pubmed.ncbi.nlm.nih.gov/36574082","citation_count":11,"is_preprint":false},{"pmid":"35532568","id":"PMC_35532568","title":"Sperm-specific protein ACTL7A as a biomarker for fertilization outcomes of assisted reproductive technology.","date":"2022","source":"Asian journal of andrology","url":"https://pubmed.ncbi.nlm.nih.gov/35532568","citation_count":11,"is_preprint":false},{"pmid":"23211711","id":"PMC_23211711","title":"Dynamic alterations in the expression and localization of ACTL7a during capacitation in mouse spermatozoa.","date":"2012","source":"Fertility and sterility","url":"https://pubmed.ncbi.nlm.nih.gov/23211711","citation_count":11,"is_preprint":false},{"pmid":"37991128","id":"PMC_37991128","title":"Novel ACTL7A variants in males lead to fertilization failure and male infertility.","date":"2023","source":"Andrology","url":"https://pubmed.ncbi.nlm.nih.gov/37991128","citation_count":7,"is_preprint":false},{"pmid":"31310081","id":"PMC_31310081","title":"Genetic Polymorphisms within The Intronless ACTL7A and ACTL7B Genes Encoding Spermatogenesis-Specific Actin-Like Proteins in Japanese Males.","date":"2019","source":"International journal of fertility & sterility","url":"https://pubmed.ncbi.nlm.nih.gov/31310081","citation_count":6,"is_preprint":false},{"pmid":"38464253","id":"PMC_38464253","title":"Novel Nuclear Roles for Testis-Specific ACTL7A and ACTL7B Supported by In Vivo Characterizations and AI Facilitated In Silico Mechanistic Modeling with Implications for Epigenetic Regulation in Spermiogenesis.","date":"2024","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/38464253","citation_count":1,"is_preprint":false},{"pmid":"41169243","id":"PMC_41169243","title":"Perinuclear theca protein FNDC8 interacts with CCIN and ACTL7A to ensure proper sperm head shaping during spermiogenesis.","date":"2025","source":"Zoological research","url":"https://pubmed.ncbi.nlm.nih.gov/41169243","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.03.27.645694","title":"Actin-related protein M1 (ARPM1) required for acrosome biogenesis and sperm function in mice","date":"2025-04-01","source":"bioRxiv","url":"https://doi.org/10.1101/2025.03.27.645694","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10919,"output_tokens":3189,"usd":0.040296},"stage2":{"model":"claude-opus-4-6","input_tokens":6597,"output_tokens":2173,"usd":0.130965},"total_usd":0.171261,"stage1_batch_id":"msgbatch_01TqNM6p6FsoMBT2jzQTwKBr","stage2_batch_id":"msgbatch_01Ya473eco8sTHbvRymQaU8o","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1999,\n      \"finding\": \"ACTL7A encodes a 435-amino-acid actin-like protein (predicted molecular mass 48.6 kDa) expressed in a wide variety of adult tissues; it is an intronless gene located on chromosome 9q31 in a head-to-head orientation with ACTL7B on a common 8-kb HindIII fragment.\",\n      \"method\": \"cDNA selection, direct genomic sequencing, linkage mapping\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — original cloning and mapping study with direct sequencing; single lab\",\n      \"pmids\": [\"10373328\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"During capacitation in mouse spermatozoa, ACTL7A expression is upregulated via the PKA pathway and its localization undergoes remodeling, indicating it is an essential component of the capacitation process.\",\n      \"method\": \"Western blot and indirect immunostaining of capacitated vs. non-capacitated mouse sperm; PKA pathway analysis\",\n      \"journal\": \"Fertility and sterility\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — two orthogonal methods (western blot + immunostaining) in a single lab; pathway identified via pharmacological approach\",\n      \"pmids\": [\"23211711\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Anti-ACTL7A antibodies cause agglutination of mouse and human spermatozoa in vitro and markedly reduce sperm fertilizing capacity; active immunization of mice with ACTL7A protein significantly reduces fertility, establishing ACTL7A as a target of immunologic infertility.\",\n      \"method\": \"In vitro sperm agglutination assay, fertility assay in immunized mice, mass spectrometry identification, indirect immunostaining\",\n      \"journal\": \"Fertility and sterility\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional fertility assay with antibody treatment plus active immunization; single lab\",\n      \"pmids\": [\"22386842\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"A homozygous missense mutation in ACTL7A causes acrosomal ultrastructural defects in human and mouse sperm, and results in reduced expression and abnormal localization of PLCζ in sperm, linking ACTL7A to oocyte activation competence and early embryonic arrest.\",\n      \"method\": \"Whole-exome sequencing, knock-in mouse model, transmission electron microscopy (TEM), immunofluorescence, western blot, artificial oocyte activation rescue\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (TEM, IF, WB, mouse model, functional rescue); replicated in human and mouse\",\n      \"pmids\": [\"32923619\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Compound heterozygous loss-of-function variants in ACTL7A cause ultrastructural defects in the acrosome and perinuclear theca, and significantly reduce PLCζ protein expression in sperm, leading to oocyte activation deficiency and total fertilization failure.\",\n      \"method\": \"Whole-exome sequencing, Sanger sequencing, TEM, immunofluorescence, western blotting, AOA rescue (calcium ionophore A23187)\",\n      \"journal\": \"Human reproduction (Oxford, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple methods in single family; consistent with prior work\",\n      \"pmids\": [\"34727571\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"ACTL7A forms a complex with zona pellucida binding protein (ZPBP), and loss of ACTL7A in knockout mice alters ZPBP localization in sperm, reducing sperm–zona pellucida binding ability and contributing to fertilization failure.\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence, knockout mouse model, IVF/ICSI functional assay\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP plus functional KO phenotype; single lab\",\n      \"pmids\": [\"35921706\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"A pathogenic missense variant in ACTL7A (p.Gly402Ser) causes the mutant protein to fail to attach to the acroplaxome and to be discharged in cytoplasmic droplets, resulting in absence of ACTL7A in epididymal spermatozoa, acrosome detachment from the nuclear membrane (bubble-shaped acrosomes), and discharge of PLCζ, leading to total fertilization failure.\",\n      \"method\": \"Knock-in mouse model, TEM, immunofluorescence, immunoprecipitation followed by LC-MS, western blot, AOA rescue\",\n      \"journal\": \"Molecular human reproduction\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — combined structural (TEM), interactome (IP-MS), functional (mouse model + rescue), multiple orthogonal methods; single lab but comprehensive\",\n      \"pmids\": [\"35863052\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"A novel homozygous missense mutation (p.D75A) in ACTL7A leads to protein degradation in sperm, acrosomal ultrastructural defects and irregular perinuclear theca, and abnormal localization and reduced expression of PLCζ, causing fertilization failure after ICSI.\",\n      \"method\": \"WES, 3D structural modeling, immunofluorescence, western blot, TEM\",\n      \"journal\": \"Molecular genetics and genomics: MGG\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — immunofluorescence + WB + TEM; structural modeling is in silico; single lab\",\n      \"pmids\": [\"36574082\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"ACTL7A is dynamically localized within the nucleus and subacrosomal space in developing spermatids and later in postacrosomal regions; knockout of Actl7a causes complete loss of subacrosomal filamentous actin (F-actin) structures, indicating ACTL7A is required for acroplaxome-associated F-actin formation and acrosomal attachment integrity.\",\n      \"method\": \"Actl7a knockout mouse model, immunofluorescence (including F-actin staining), live/fixed imaging of developing spermatids\",\n      \"journal\": \"Molecular human reproduction\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with defined cellular phenotype (loss of F-actin) plus dynamic localization imaging; mechanistic model supported by multiple observations\",\n      \"pmids\": [\"36734600\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Loss of ACTL7A in knockout mice causes small-head sperm due to defective acrosome-acroplaxome-manchette complex formation; proteomics revealed that ACTL7A loss activates autophagy inhibition via the PI3K/AKT/mTOR pathway, leading to PDLIM1 accumulation and hindered manchette development.\",\n      \"method\": \"Actl7a KO mouse model, immunofluorescence, TEM, tandem mass tag quantitative proteomics, western blot, ICSI-AOA rescue\",\n      \"journal\": \"Reproductive biology and endocrinology: RB&E\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse + proteomics + IF + TEM; pathway placement via proteomics inference; single lab\",\n      \"pmids\": [\"37667331\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Homozygous nonsense variant in ACTL7A causes increased thickness of the perinuclear matrix and detachment of the acrosome from the nuclear envelope as observed by TEM, further confirming ACTL7A's structural role in perinuclear theca integrity.\",\n      \"method\": \"WES, TEM, immunofluorescence\",\n      \"journal\": \"Clinical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — TEM phenotype in human patient; consistent with multiple prior reports\",\n      \"pmids\": [\"36593593\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ACTL7A is present in the nucleus of developing spermatids; in the absence of ACTL7A, intranuclear localization of HDAC1 and HDAC3 is lost, implicating ACTL7A in chromatin regulatory complex function during spermiogenesis. In silico modeling further suggests ACTL7A can substitute for actin/ACTL6A in binding HSA domains of INO80 and SWI/SNF nucleosome remodeling complexes.\",\n      \"method\": \"Actl7a KO mouse model, immunofluorescence for HDAC1/HDAC3 nuclear localization, testis transcriptomic analysis, AI-facilitated in silico structural modeling\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3–4 — in vivo localization change is Tier 3; mechanistic model for nucleosome remodeler interaction is computational only; preprint\",\n      \"pmids\": [\"38464253\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ACTL7A interacts with the perinuclear theca protein FNDC8 and with CCIN during spermiogenesis; depletion of FNDC8 destabilizes ACTL7A protein, placing ACTL7A downstream of FNDC8 in a PT protein interaction network required for sperm head morphogenesis.\",\n      \"method\": \"Co-immunoprecipitation, Fndc8 knockout mouse model, immunofluorescence, western blot\",\n      \"journal\": \"Zoological research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP plus KO mouse with defined phenotype; single lab\",\n      \"pmids\": [\"41169243\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ACTL7A interacts with ARPM1 (ACTRT3) as shown by co-immunoprecipitation; ARPM1 deficiency does not directly ablate ACTL7A but ACTL7A is part of the PT cytoskeletal complex that also includes ACTRT1, ACTRT2, and ZPBP.\",\n      \"method\": \"Co-immunoprecipitation from mouse testis/sperm lysates\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single Co-IP; preprint, no functional follow-up specific to ACTL7A\",\n      \"pmids\": [\"bio_10.1101_2025.03.27.645694\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"ACTL7A is a testis-enriched actin-related protein that localizes dynamically to the nucleus, subacrosomal space, and postacrosomal perinuclear theca (PT) of developing spermatids, where it is essential for acroplaxome-associated F-actin formation and acrosomal anchoring to the nuclear surface; loss-of-function mutations cause acrosomal detachment, small-head sperm via defective acrosome-acroplaxome-manchette complex, and reduced/mislocalized PLCζ, abolishing oocyte activation and causing total fertilization failure, while its expression during capacitation is upregulated through the PKA pathway and it participates in a PT protein complex with FNDC8, CCIN, ZPBP, and ARPM1.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ACTL7A is a testis-enriched actin-related protein essential for spermiogenesis, acrosome biogenesis, and male fertility. During spermatid development, ACTL7A localizes dynamically to the nucleus, subacrosomal space, and postacrosomal perinuclear theca, where it is required for acroplaxome-associated F-actin assembly and stable anchoring of the acrosome to the nuclear envelope; loss of ACTL7A abolishes subacrosomal F-actin structures, causes acrosomal detachment, small-head sperm morphology through defective acrosome-acroplaxome-manchette complex formation, and loss of intranuclear HDAC1/HDAC3 localization [PMID:36734600, PMID:37667331, PMID:35863052, PMID:38464253]. ACTL7A participates in a perinuclear theca protein complex with FNDC8, CCIN, ZPBP, and ARPM1, and its stability depends on FNDC8 [PMID:41169243, PMID:35921706]. Homozygous or compound heterozygous loss-of-function mutations in ACTL7A cause total fertilization failure in humans by disrupting acrosomal ultrastructure, reducing PLCζ expression and localization in sperm, and abolishing oocyte activation competence [PMID:32923619, PMID:34727571].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Identification of ACTL7A as an intronless actin-related gene on chromosome 9q31, clustered with ACTL7B, established it as a novel member of the actin-related protein family expressed broadly in adult tissues.\",\n      \"evidence\": \"cDNA selection and direct genomic sequencing with linkage mapping\",\n      \"pmids\": [\"10373328\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional data; expression breadth not reconciled with later testis-enrichment findings\", \"No protein-level characterization\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Demonstration that ACTL7A is upregulated via the PKA pathway during capacitation and that anti-ACTL7A antibodies block fertilization established ACTL7A as a functionally important sperm surface/structural component required for fertility.\",\n      \"evidence\": \"Western blot and immunostaining of capacitated mouse sperm; in vitro agglutination assays; active immunization fertility assays in mice\",\n      \"pmids\": [\"23211711\", \"22386842\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism of PKA-dependent upregulation undefined\", \"Whether antibody effects reflect surface exposure or secondary disruption unclear\", \"No genetic loss-of-function model yet\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"A homozygous ACTL7A missense mutation in a human family, recapitulated in a knock-in mouse, linked ACTL7A directly to acrosomal ultrastructural integrity and PLCζ-dependent oocyte activation, establishing it as a cause of total fertilization failure.\",\n      \"evidence\": \"WES in infertile patient, knock-in mouse model, TEM, immunofluorescence, western blot, artificial oocyte activation rescue\",\n      \"pmids\": [\"32923619\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which ACTL7A controls PLCζ expression/localization unknown\", \"Single family — allelic spectrum not yet defined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identification of compound heterozygous ACTL7A variants causing the same phenotype confirmed that biallelic loss-of-function is a recurrent genetic cause of oocyte activation deficiency and fertilization failure in humans.\",\n      \"evidence\": \"WES, Sanger validation, TEM, immunofluorescence, western blot, calcium ionophore rescue in a second family\",\n      \"pmids\": [\"34727571\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Still limited to two families\", \"Carrier frequency and population-level contribution unknown\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"A series of studies using knock-in/knockout mouse models and proteomics defined the precise structural role of ACTL7A: it anchors to the acroplaxome, and specific mutations (e.g., G402S) cause the protein to be discharged in cytoplasmic droplets, resulting in bubble-shaped acrosomes; ACTL7A also forms a complex with ZPBP to facilitate zona pellucida binding.\",\n      \"evidence\": \"Knock-in and knockout mouse models, TEM, IP-LC/MS interactome, Co-IP with ZPBP, IVF/ICSI functional assays\",\n      \"pmids\": [\"35863052\", \"35921706\", \"36574082\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct binding interface between ACTL7A and ZPBP uncharacterized\", \"How ACTL7A is recruited to the acroplaxome molecularly remains unclear\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Knockout studies revealed that ACTL7A is absolutely required for subacrosomal F-actin formation and that its loss causes small-head sperm through defective acrosome-acroplaxome-manchette complex assembly, with proteomics implicating PI3K/AKT/mTOR-mediated autophagy inhibition and PDLIM1 accumulation as downstream consequences.\",\n      \"evidence\": \"Actl7a KO mouse, F-actin staining, live/fixed imaging, TEM, TMT quantitative proteomics, western blot\",\n      \"pmids\": [\"36734600\", \"37667331\", \"36593593\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ACTL7A directly polymerizes or nucleates F-actin is unknown\", \"PI3K/AKT/mTOR pathway link is correlative from proteomics, not validated by pathway perturbation\", \"PDLIM1 role in manchette development not independently confirmed\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identification of FNDC8 and CCIN as direct interaction partners that stabilize ACTL7A protein placed ACTL7A within a hierarchical perinuclear theca protein network required for sperm head morphogenesis.\",\n      \"evidence\": \"Co-immunoprecipitation, Fndc8 KO mouse model, immunofluorescence, western blot\",\n      \"pmids\": [\"41169243\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Stoichiometry and assembly order of the PT complex not defined\", \"Whether FNDC8 stabilizes ACTL7A directly or through a scaffold is unclear\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include whether ACTL7A has intrinsic actin-like polymerization or ATPase activity, the structural basis of its integration into the acroplaxome, the mechanism by which it controls PLCζ retention in sperm, and whether it substitutes for canonical actin in nuclear chromatin-remodeling complexes during spermiogenesis.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No biochemical reconstitution of ACTL7A polymerization or ATPase activity\", \"No crystal or cryo-EM structure\", \"Chromatin remodeler interaction model is computational only\", \"PLCζ retention mechanism completely undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [8, 9, 12, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [8, 11]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [8, 6, 9]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1474165\", \"supporting_discovery_ids\": [3, 4, 6, 8, 9]}\n    ],\n    \"complexes\": [\n      \"Perinuclear theca complex (FNDC8–CCIN–ACTL7A–ZPBP)\"\n    ],\n    \"partners\": [\n      \"ZPBP\",\n      \"FNDC8\",\n      \"CCIN\",\n      \"PLCZ1\",\n      \"ARPM1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}