{"gene":"SPECC1L","run_date":"2026-06-10T07:46:39","timeline":{"discoveries":[{"year":2011,"finding":"SPECC1L colocalizes with both tubulin and actin in mammalian cells, and its deficiency results in defective actin-cytoskeleton reorganization, as well as abnormal cell adhesion and migration. Knockdown in Drosophila phenocopies mutants in the integrin signaling pathway.","method":"Immunofluorescence colocalization, siRNA knockdown in mammalian cells (cell adhesion/migration assays), Drosophila morpholino knockdown","journal":"American journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct colocalization plus loss-of-function with defined cellular phenotypes (actin reorganization, adhesion, migration), single lab, multiple orthogonal methods","pmids":["21703590"],"is_preprint":false},{"year":2016,"finding":"SPECC1L knockdown in cultured cells increases staining and apico-basal diffusion of canonical adherens junction (AJ) components β-catenin and E-cadherin. In Specc1l-deficient mouse embryos, AJ stability is increased, impairing cranial neural crest cell (CNCC) delamination. PI3K-AKT signaling is reduced in mutants; moderate PI3K-AKT inhibition in wildtype cells reproduces AJ alterations; and activating PI3K-AKT rescues AJ changes caused by SPECC1L knockdown, placing SPECC1L as a novel modulator of PI3K-AKT signaling and AJ biology.","method":"siRNA knockdown in cultured cells (immunostaining, electron microscopy), mouse gene-trap knockout (immunostaining, CNCC lineage analysis), pharmacological PI3K-AKT inhibition/activation rescue experiments","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal genetic and pharmacological rescue, multiple orthogonal methods (EM, immunostaining, mouse KO, cell culture KD), replicated across in vitro and in vivo systems","pmids":["26787558"],"is_preprint":false},{"year":2020,"finding":"SPECC1L mutations cluster in the second coiled-coil (CCD2) and calponin homology domains and severely affect the ability of SPECC1L to associate with microtubules. SPECC1L expression is drastically reduced in Irf6 mutant palatal shelves, placing SPECC1L downstream of IRF6 in palatogenesis. SPECC1L deficiency causes periderm layer abnormalities including ectopic apical expression of adherens junction markers.","method":"Mouse Specc1l truncation alleles (compound heterozygotes), immunostaining of palatal shelves, Irf6 mutant mouse analysis, sequencing of nsCL/P patient cohorts","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis (Irf6 mutant reduces SPECC1L expression) plus mouse mutant immunostaining, single lab, multiple orthogonal methods","pmids":["31943082"],"is_preprint":false},{"year":2021,"finding":"Wild-type SPECC1L distributes evenly throughout the cytoplasm and colocalizes with both microtubules and filamentous actin. Mutant SPECC1L lacking CCD2 (SPECC1L-ΔCCD2) shows abnormal perinuclear accumulation with diminished microtubule overlap, demonstrating SPECC1L uses microtubule association for intracellular trafficking. CCD2 deletion results in gain-of-function: increased actin and non-muscle myosin II bundles displaced to the cell periphery, disrupting actomyosin organization and tissue fusion dynamics (exencephaly, cleft palate, omphalocele in homozygous mice).","method":"Mouse in-frame deletion alleles (Specc1lΔCCD2), immunofluorescence colocalization of SPECC1L with microtubules and F-actin, non-muscle myosin II staining, mouse embryo phenotypic analysis","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — structure-function mutagenesis (in-frame CCD2 deletion) combined with cell imaging and mouse in vivo phenotypes, multiple orthogonal readouts in single rigorous study","pmids":["34302166"],"is_preprint":false},{"year":2021,"finding":"SPECC1L-deficient primary mouse embryonic palatal mesenchyme (MEPM) cells show reduced cell speed and defective coordinated (collective) cell movement in wound-repair assays. Activation of the PI3K-AKT pathway rescues both cell speed and directional guidance defects in Specc1l mutant MEPM cells, confirming SPECC1L modulates collective mesenchymal cell movement through PI3K-AKT signaling.","method":"Live-imaging wound-repair assays of primary MEPM cells from Specc1l mutant mice, pharmacological PI3K-AKT activation rescue","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — primary cell live-imaging plus pharmacological rescue, single lab, two orthogonal methods","pmids":["33446878"],"is_preprint":false},{"year":2023,"finding":"SPECC1L directly binds MYPT1 and forms a stable complex with the myosin phosphatase holoenzyme MYPT1/PP1β. SPECC1L can regulate the balance of MYPT1/PP1β distribution between microtubule and filamentous actin networks, suggesting it acts as a scaffold that traffics this phosphatase between cytoskeletal substrates.","method":"Co-immunoprecipitation, proximity biotinylation (BioID), direct binding assay, interactome comparison of SPECC1L and MYPT1","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — direct binding assay plus reciprocal co-IP and orthogonal proximity biotinylation, interactome overlap validation, multiple methods in single rigorous study","pmids":["36634848"],"is_preprint":false},{"year":2023,"finding":"SPECC1L associates with microtubules, filamentous actin, non-muscle myosin II (NMII), and membrane-associated components of adherens junctions, functioning as a cytoskeletal scaffolding protein. Syndromic SPECC1L mutations act through a gain-of-function mechanism to affect intra- and supra-cellular actin organization.","method":"Review/synthesis of multiple experimental findings (colocalization, co-IP, mouse models)","journal":"Biochemical Society transactions","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — consolidation of replicated experimental data from multiple papers and methods; review but citing primary experimental evidence","pmids":["37345651"],"is_preprint":false},{"year":2023,"finding":"SPECC1L is required for proper bipolar spindle assembly during mouse oocyte meiotic maturation. Specc1l knockdown in oocytes caused abnormal spindle morphology, misaligned chromosomes, decreased polar body extrusion, and reduced blastocyst formation. SPECC1L localizes to cytoplasm and germinal vesicle but not to the nucleolus-like body or chromatin.","method":"siRNA knockdown in mouse oocytes, immunofluorescence localization, live-imaging of spindle assembly and polar body extrusion","journal":"Reproduction (Cambridge, England)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA KD with defined cellular phenotype (spindle, chromosome alignment) plus direct localization, single lab","pmids":["37698179"],"is_preprint":false},{"year":2025,"finding":"Loss of SPECC1L specifically in cranial neural crest cells (Wnt1-Cre2 conditional KO) causes shortened primary cilia and increased Hedgehog (Hh) signaling (elevated GLI1) in cranial mesenchyme from E9.5, resulting in frontonasal dysplasia features. SPECC1L itself does not localize to cilia but regulates cilia length indirectly through F-actin regulation.","method":"Conditional Specc1l knockout (Wnt1-Cre2 × Specc1l-flox), GLI1 immunostaining, primary cilia length measurement, embryo phenotypic analysis","journal":"Frontiers in physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-type-specific conditional KO with mechanistic readouts (cilia length, Hh/GLI1 signaling), single lab","pmids":["41657552"],"is_preprint":false},{"year":2025,"finding":"SPECC1L loss leads to increased F-actin levels and shortened primary cilia. Depolymerizing F-actin in Specc1l mutant cells restored cilia length, establishing a causal inverse relationship between SPECC1L-regulated F-actin and cilia length. A genetic interaction between Specc1l and Thm1 (IFT-A component) was identified: compound/double heterozygotes show higher penetrance of cleft palate than Specc1l heterozygotes alone.","method":"F-actin depolymerization rescue of cilia length in Specc1l mutant cells, genetic compound heterozygote analysis (Specc1l × Thm1), cilia length measurement","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological rescue experiment plus genetic epistasis, single lab, preprint","pmids":["41278885"],"is_preprint":true},{"year":2025,"finding":"The Drosophila SPECC1L homolog Split Discs (Spdi) co-localizes with non-muscle myosin II and actin (not microtubules as proposed for the mammalian protein). RNAi depletion of Spdi increases focal adhesion dynamics. Conserved point mutations analogous to human disease variants cause a further increase in focal adhesion dynamics beyond knockdown alone, suggesting disease mutations affect cell-matrix adhesion through NMII association.","method":"RNAi depletion in Drosophila cells, immunofluorescence colocalization with NMII/actin, focal adhesion dynamics assays, site-directed mutagenesis of disease-analogous residues","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi KD plus structure-function mutagenesis with defined cellular phenotype (focal adhesion dynamics), single lab, preprint ortholog study","pmids":["40236004"],"is_preprint":true},{"year":2025,"finding":"An intragenic SPECC1L deletion encompassing exon 3 (containing the canonical start codon) leads to alternative start codon usage and protein truncation, demonstrating the N-terminal disordered region is required for normal SPECC1L translation initiation and function in craniofacial development.","method":"Functional overexpression assay of deletion construct, protein truncation analysis, Sanger sequencing","journal":"NPJ genomic medicine","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single overexpression assay demonstrating alternative start site usage, no in vivo or cellular rescue, single lab","pmids":["41120295"],"is_preprint":false}],"current_model":"SPECC1L is a cytoskeletal scaffolding protein that associates with microtubules (via its CCD2 domain), filamentous actin, and adherens junction components; it forms a stable complex with the myosin phosphatase MYPT1/PP1β (which it can direct between microtubule and actin networks), modulates PI3K-AKT signaling to control adherens junction stability and collective cell movement, regulates actomyosin (non-muscle myosin II) organization and spindle assembly, and indirectly controls primary cilia length through F-actin levels—collectively making it a central regulator of tissue movement and fusion events during embryogenesis, particularly in cranial neural crest cell delamination and craniofacial morphogenesis."},"narrative":{"mechanistic_narrative":"SPECC1L is a cytoskeletal scaffolding protein that coordinates actin and microtubule networks to drive the tissue movement and fusion events of craniofacial morphogenesis, particularly cranial neural crest cell (CNCC) delamination and palatogenesis [PMID:21703590, PMID:26787558, PMID:34302166]. It colocalizes with both microtubules and filamentous actin, using a second coiled-coil domain (CCD2) for microtubule association and intracellular trafficking; CCD2 deletion produces a gain-of-function state with excess actin and non-muscle myosin II bundles displaced to the cell periphery, disrupting actomyosin organization and producing exencephaly, cleft palate, and omphalocele in mice [PMID:34302166]. SPECC1L directly binds MYPT1 and forms a stable complex with the myosin phosphatase holoenzyme MYPT1/PP1β, distributing this phosphatase between microtubule and actin networks [PMID:36634848]. Functionally, SPECC1L restrains adherens junction stability—its loss increases β-catenin and E-cadherin junctional signal and impairs CNCC delamination—acting through PI3K-AKT signaling, since PI3K-AKT activation rescues both the junctional defects and the impaired collective movement of mutant palatal mesenchyme cells [PMID:26787558, PMID:33446878]. In CNCCs, SPECC1L additionally limits F-actin levels to control primary cilium length and thereby Hedgehog signaling, without itself localizing to cilia [PMID:41657552, PMID:41278885]. SPECC1L is also required for bipolar spindle assembly and chromosome alignment during oocyte meiotic maturation [PMID:37698179]. Genetically, SPECC1L lies downstream of IRF6 in palatogenesis, and disease-associated mutations cluster in CCD2 and the calponin homology domains, acting through a gain-of-function mechanism to perturb actin organization [PMID:31943082, PMID:37345651].","teleology":[{"year":2011,"claim":"Established SPECC1L as a dual cytoskeletal-associated protein whose loss disrupts actin reorganization, adhesion, and migration, framing it as a candidate regulator of cell movement.","evidence":"Immunofluorescence colocalization with tubulin and actin, siRNA knockdown adhesion/migration assays in mammalian cells, Drosophila knockdown phenocopying integrin pathway mutants","pmids":["21703590"],"confidence":"Medium","gaps":["No molecular partners identified","Mechanism linking SPECC1L to integrin signaling unresolved","No structure-function mapping of domains"]},{"year":2016,"claim":"Placed SPECC1L mechanistically upstream of adherens junction stability and PI3K-AKT signaling, explaining the CNCC delamination defect underlying craniofacial disease.","evidence":"siRNA knockdown with immunostaining/EM, mouse gene-trap knockout with CNCC lineage analysis, reciprocal pharmacological PI3K-AKT inhibition and activation rescue","pmids":["26787558"],"confidence":"High","gaps":["Direct molecular link between SPECC1L and PI3K-AKT components not defined","Whether AJ effect is via cytoskeleton or signaling not separated"]},{"year":2020,"claim":"Defined where disease mutations cluster (CCD2 and calponin homology domains) and their effect on microtubule association, and positioned SPECC1L downstream of IRF6 in palatogenesis.","evidence":"Mouse truncation alleles, palatal shelf immunostaining, Irf6 mutant analysis, nsCL/P patient cohort sequencing","pmids":["31943082"],"confidence":"Medium","gaps":["How IRF6 regulates SPECC1L expression unknown","Functional consequence of lost microtubule association not yet tied to phenotype"]},{"year":2021,"claim":"Resolved CCD2 as the microtubule-trafficking determinant and showed its deletion is a gain-of-function that displaces actomyosin bundles, mechanistically connecting domain loss to actin/NMII dysregulation and tissue fusion failure.","evidence":"Mouse in-frame Specc1lΔCCD2 alleles, immunofluorescence colocalization, NMII staining, embryo phenotyping","pmids":["34302166"],"confidence":"High","gaps":["Molecular basis of the gain-of-function actin effect not defined","Cargo trafficked along microtubules not identified at this stage"]},{"year":2021,"claim":"Connected the cellular adhesion/migration defect to PI3K-AKT by showing pathway activation rescues collective movement of primary mutant mesenchyme cells.","evidence":"Live-imaging wound-repair assays of primary MEPM cells from Specc1l mutants with pharmacological PI3K-AKT activation rescue","pmids":["33446878"],"confidence":"Medium","gaps":["Direct biochemical link between SPECC1L and PI3K-AKT still missing","How cytoskeletal scaffolding feeds into directional guidance unclear"]},{"year":2023,"claim":"Identified the first direct molecular partner, MYPT1/PP1β myosin phosphatase, and proposed SPECC1L as a scaffold that traffics the phosphatase between microtubule and actin networks—providing a biochemical mechanism for actomyosin regulation.","evidence":"Co-immunoprecipitation, BioID proximity biotinylation, direct binding assay, SPECC1L/MYPT1 interactome comparison","pmids":["36634848"],"confidence":"High","gaps":["Whether phosphatase redistribution drives the craniofacial phenotype not tested in vivo","Substrates of the redistributed phosphatase not enumerated"]},{"year":2023,"claim":"Extended SPECC1L function to meiotic spindle assembly, indicating its cytoskeletal scaffolding role operates beyond craniofacial tissues.","evidence":"siRNA knockdown in mouse oocytes, immunofluorescence localization, live-imaging of spindle assembly and polar body extrusion","pmids":["37698179"],"confidence":"Medium","gaps":["Molecular mechanism in spindle assembly unknown","Whether MYPT1/PP1β complex participates in oocyte phenotype untested"]},{"year":2025,"claim":"Linked SPECC1L to primary cilium length and Hedgehog signaling in CNCCs via F-actin control, establishing a causal F-actin–cilia axis and a genetic interaction with the IFT-A component THM1.","evidence":"Wnt1-Cre2 conditional knockout with GLI1 immunostaining and cilia measurements; F-actin depolymerization rescue and Specc1l×Thm1 compound heterozygote analysis (one preprint)","pmids":["41657552","41278885"],"confidence":"Medium","gaps":["How F-actin level controls ciliogenesis mechanistically not defined","THM1 interaction is genetic, not biochemical"]},{"year":2025,"claim":"Tested the conserved Drosophila ortholog Spdi, supporting NMII/actin association and a gain-of-function effect of disease-analogous mutations on focal adhesion dynamics.","evidence":"RNAi depletion in Drosophila cells, NMII/actin colocalization, focal adhesion dynamics assays, site-directed mutagenesis (preprint)","pmids":["40236004"],"confidence":"Medium","gaps":["Ortholog did not colocalize with microtubules, leaving cross-species mechanism partly divergent","Preprint, not peer-reviewed"]},{"year":2025,"claim":"Indicated the N-terminal disordered region is needed for correct translation initiation, since an exon 3 deletion forces alternative start codon usage and protein truncation.","evidence":"Functional overexpression assay of a deletion construct, protein truncation analysis, Sanger sequencing","pmids":["41120295"],"confidence":"Low","gaps":["Single overexpression assay with no cellular or in vivo rescue","Functional consequence of the truncated protein not characterized"]},{"year":null,"claim":"How SPECC1L mechanistically couples its cytoskeletal scaffolding and MYPT1/PP1β trafficking to PI3K-AKT signaling, adherens junction control, and F-actin/cilia regulation within a single unified pathway remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No direct biochemical link between SPECC1L and PI3K-AKT identified","Whether the MYPT1/PP1β complex mediates the AJ, cilia, and spindle phenotypes untested","Structural basis of CCD2/CH-domain cytoskeletal binding undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0,3,5,6]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[5,6]}],"localization":[{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[0,3,6]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[3,7]}],"pathway":[{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[1,2,3,8]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,4,8]}],"complexes":["MYPT1/PP1β myosin phosphatase holoenzyme"],"partners":["MYPT1","PPP1CB"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q69YQ0","full_name":"Cytospin-A","aliases":["Renal carcinoma antigen NY-REN-22","Sperm antigen with calponin homology and coiled-coil domains 1-like","SPECC1-like protein"],"length_aa":1117,"mass_kda":124.5,"function":"Involved in cytokinesis and spindle organization. May play a role in actin cytoskeleton organization and microtubule stabilization and hence required for proper cell adhesion and migration","subcellular_location":"Cytoplasm, cytoskeleton; Cytoplasm, cytoskeleton, spindle; Cell junction, gap junction","url":"https://www.uniprot.org/uniprotkb/Q69YQ0/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SPECC1L","classification":"Not Classified","n_dependent_lines":70,"n_total_lines":1208,"dependency_fraction":0.057947019867549666},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/SPECC1L","total_profiled":1310},"omim":[{"mim_id":"614140","title":"SPERM ANTIGEN WITH CALPONIN HOMOLOGY AND COILED-COIL DOMAINS 1-LIKE; SPECC1L","url":"https://www.omim.org/entry/614140"},{"mim_id":"600251","title":"FACIAL CLEFTING, OBLIQUE, 1; OBLFC1","url":"https://www.omim.org/entry/600251"},{"mim_id":"300000","title":"OPITZ GBBB SYNDROME; GBBB","url":"https://www.omim.org/entry/300000"},{"mim_id":"145420","title":"TEEBI HYPERTELORISM SYNDROME 1; TBHS1","url":"https://www.omim.org/entry/145420"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Actin filaments","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/SPECC1L"},"hgnc":{"alias_symbol":["KIAA0376"],"prev_symbol":["CYTSA"]},"alphafold":{"accession":"Q69YQ0","domains":[{"cath_id":"-","chopping":"502-595_606-777","consensus_level":"medium","plddt":91.9248,"start":502,"end":777},{"cath_id":"1.10.418.10","chopping":"1011-1117","consensus_level":"high","plddt":91.6327,"start":1011,"end":1117}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q69YQ0","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q69YQ0-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q69YQ0-F1-predicted_aligned_error_v6.png","plddt_mean":65.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SPECC1L","jax_strain_url":"https://www.jax.org/strain/search?query=SPECC1L"},"sequence":{"accession":"Q69YQ0","fasta_url":"https://rest.uniprot.org/uniprotkb/Q69YQ0.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q69YQ0/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q69YQ0"}},"corpus_meta":[{"pmid":"21703590","id":"PMC_21703590","title":"Deficiency of the cytoskeletal protein SPECC1L leads to oblique facial clefting.","date":"2011","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21703590","citation_count":77,"is_preprint":false},{"pmid":"26787558","id":"PMC_26787558","title":"SPECC1L deficiency results in increased adherens junction stability and reduced cranial neural crest cell delamination.","date":"2016","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/26787558","citation_count":44,"is_preprint":false},{"pmid":"25412741","id":"PMC_25412741","title":"Mutations in SPECC1L, encoding sperm antigen with calponin homology and coiled-coil domains 1-like, are found in some cases of autosomal dominant Opitz G/BBB syndrome.","date":"2014","source":"Journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/25412741","citation_count":39,"is_preprint":false},{"pmid":"26111080","id":"PMC_26111080","title":"Expanding the SPECC1L mutation phenotypic spectrum to include Teebi hypertelorism syndrome.","date":"2015","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/26111080","citation_count":32,"is_preprint":false},{"pmid":"30472488","id":"PMC_30472488","title":"Phenotypic spectrum associated with SPECC1L pathogenic variants: new families and critical review of the nosology of Teebi, Opitz GBBB, and Baraitser-Winter syndromes.","date":"2018","source":"European journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/30472488","citation_count":30,"is_preprint":false},{"pmid":"31943082","id":"PMC_31943082","title":"SPECC1L regulates palate development downstream of IRF6.","date":"2020","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/31943082","citation_count":24,"is_preprint":false},{"pmid":"25357034","id":"PMC_25357034","title":"Functional analysis of SPECC1L in craniofacial development and oblique facial cleft pathogenesis.","date":"2014","source":"Plastic and reconstructive surgery","url":"https://pubmed.ncbi.nlm.nih.gov/25357034","citation_count":22,"is_preprint":false},{"pmid":"34302166","id":"PMC_34302166","title":"In-frame deletion of SPECC1L microtubule association domain results in gain-of-function phenotypes affecting embryonic tissue movement and fusion events.","date":"2021","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/34302166","citation_count":15,"is_preprint":false},{"pmid":"37345651","id":"PMC_37345651","title":"SPECC1L: a cytoskeletal protein that regulates embryonic tissue dynamics.","date":"2023","source":"Biochemical Society transactions","url":"https://pubmed.ncbi.nlm.nih.gov/37345651","citation_count":12,"is_preprint":false},{"pmid":"33446878","id":"PMC_33446878","title":"SPECC1L-deficient primary mouse embryonic palatal mesenchyme cells show speed and directionality defects.","date":"2021","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/33446878","citation_count":12,"is_preprint":false},{"pmid":"36634848","id":"PMC_36634848","title":"SPECC1L binds the myosin phosphatase complex MYPT1/PP1β and can regulate its distribution between microtubules and filamentous actin.","date":"2023","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/36634848","citation_count":11,"is_preprint":false},{"pmid":"31953237","id":"PMC_31953237","title":"A novel SPECC1L mutation causing Teebi hypertelorism syndrome: Expanding phenotypic and genetic spectrum.","date":"2020","source":"European journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/31953237","citation_count":10,"is_preprint":false},{"pmid":"32954677","id":"PMC_32954677","title":"Congenital diaphragmatic hernia as a prominent feature of a SPECC1L-related syndrome.","date":"2020","source":"American journal of medical genetics. 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expression of VGF, SPECC1L, HLA-DRA and RANBP3L act with APOE E4 to alter risk for late onset Alzheimer's disease.","date":"2024","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/38942763","citation_count":3,"is_preprint":false},{"pmid":"35205294","id":"PMC_35205294","title":"SPECC1L Mutations Are Not Common in Sporadic Cases of Opitz G/BBB Syndrome.","date":"2022","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/35205294","citation_count":2,"is_preprint":false},{"pmid":"37698179","id":"PMC_37698179","title":"Specc1l deficiency leads to abnormal oocyte meiosis and reduced blastocyst development in mouse.","date":"2023","source":"Reproduction (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/37698179","citation_count":2,"is_preprint":false},{"pmid":"41278885","id":"PMC_41278885","title":"Genetic interaction of Specc1l and Thm1 reveals cytoskeletal-ciliary crosstalk.","date":"2025","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/41278885","citation_count":2,"is_preprint":false},{"pmid":"40376737","id":"PMC_40376737","title":"First Report of SPECC1L::ALK Fusion in Medullary Thyroid Carcinoma with Remarkable Response to Alectinib.","date":"2025","source":"Thyroid : official journal of the American Thyroid Association","url":"https://pubmed.ncbi.nlm.nih.gov/40376737","citation_count":2,"is_preprint":false},{"pmid":"39661164","id":"PMC_39661164","title":"NTRK-rearranged spindle cell tumor with SPECC1L-NTRK3 fusion in the thoracic spine: a case report.","date":"2024","source":"Journal of cancer research and clinical oncology","url":"https://pubmed.ncbi.nlm.nih.gov/39661164","citation_count":2,"is_preprint":false},{"pmid":"40725486","id":"PMC_40725486","title":"Oral Undifferentiated Pleomorphic Sarcoma: A Novel SPECC1L::TERT Gene Fusion and a Comprehensive Literature 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medicine","url":"https://pubmed.ncbi.nlm.nih.gov/39063924","citation_count":0,"is_preprint":false},{"pmid":"38168398","id":"PMC_38168398","title":"The Human Brainome: changes in expression of VGF, SPECC1L, HLA-DRA and RANBP3L act with APOE E4 to alter risk for late onset Alzheimer's disease.","date":"2023","source":"Research square","url":"https://pubmed.ncbi.nlm.nih.gov/38168398","citation_count":0,"is_preprint":false},{"pmid":"41211450","id":"PMC_41211450","title":"Case Report: Dual resistance to dasatinib/olverembatinib in accelerated-phase cml: identification of a novel SPECC1L-inserted e8a2 BCR::ABL1 transcript and ABL1 V379I mutation.","date":"2025","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/41211450","citation_count":0,"is_preprint":false},{"pmid":"41332626","id":"PMC_41332626","title":"Loss of SPECC1L in cranial neural crest cells results in increased hedgehog signaling and frontonasal dysplasia.","date":"2025","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/41332626","citation_count":0,"is_preprint":false},{"pmid":"37532501","id":"PMC_37532501","title":"[Identification of a child with Teebi hypertelorism syndrome 1 due to variant of SPECC1L gene].","date":"2023","source":"Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/37532501","citation_count":0,"is_preprint":false},{"pmid":"40236004","id":"PMC_40236004","title":"The Drosophila SPECC1L homolog, Split Discs, co-localizes with non-muscle myosin II and regulates focal adhesion dynamics.","date":"2025","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/40236004","citation_count":0,"is_preprint":false},{"pmid":"41657552","id":"PMC_41657552","title":"Loss of SPECC1L in cranial neural crest cells results in increased hedgehog signaling and frontonasal dysplasia.","date":"2026","source":"Frontiers in physiology","url":"https://pubmed.ncbi.nlm.nih.gov/41657552","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.11.03.686369","title":"Genetic interaction of  <i>Specc1l</i>  and  <i>Thm1</i>  reveals cytoskeletal - ciliary crosstalk","date":"2025-11-05","source":"bioRxiv","url":"https://doi.org/10.1101/2025.11.03.686369","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.04.06.647460","title":"The  <i>Drosophila</i>  SPECC1L homolog, Split Discs, co-localizes with non-muscle myosin II and regulates focal adhesion dynamics","date":"2025-04-06","source":"bioRxiv","url":"https://doi.org/10.1101/2025.04.06.647460","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":18855,"output_tokens":3382,"usd":0.053648,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":10955,"output_tokens":3651,"usd":0.073025,"stage2_stop_reason":"end_turn"},"total_usd":0.126673,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2011,\n      \"finding\": \"SPECC1L colocalizes with both tubulin and actin in mammalian cells, and its deficiency results in defective actin-cytoskeleton reorganization, as well as abnormal cell adhesion and migration. Knockdown in Drosophila phenocopies mutants in the integrin signaling pathway.\",\n      \"method\": \"Immunofluorescence colocalization, siRNA knockdown in mammalian cells (cell adhesion/migration assays), Drosophila morpholino knockdown\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct colocalization plus loss-of-function with defined cellular phenotypes (actin reorganization, adhesion, migration), single lab, multiple orthogonal methods\",\n      \"pmids\": [\"21703590\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"SPECC1L knockdown in cultured cells increases staining and apico-basal diffusion of canonical adherens junction (AJ) components β-catenin and E-cadherin. In Specc1l-deficient mouse embryos, AJ stability is increased, impairing cranial neural crest cell (CNCC) delamination. PI3K-AKT signaling is reduced in mutants; moderate PI3K-AKT inhibition in wildtype cells reproduces AJ alterations; and activating PI3K-AKT rescues AJ changes caused by SPECC1L knockdown, placing SPECC1L as a novel modulator of PI3K-AKT signaling and AJ biology.\",\n      \"method\": \"siRNA knockdown in cultured cells (immunostaining, electron microscopy), mouse gene-trap knockout (immunostaining, CNCC lineage analysis), pharmacological PI3K-AKT inhibition/activation rescue experiments\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal genetic and pharmacological rescue, multiple orthogonal methods (EM, immunostaining, mouse KO, cell culture KD), replicated across in vitro and in vivo systems\",\n      \"pmids\": [\"26787558\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"SPECC1L mutations cluster in the second coiled-coil (CCD2) and calponin homology domains and severely affect the ability of SPECC1L to associate with microtubules. SPECC1L expression is drastically reduced in Irf6 mutant palatal shelves, placing SPECC1L downstream of IRF6 in palatogenesis. SPECC1L deficiency causes periderm layer abnormalities including ectopic apical expression of adherens junction markers.\",\n      \"method\": \"Mouse Specc1l truncation alleles (compound heterozygotes), immunostaining of palatal shelves, Irf6 mutant mouse analysis, sequencing of nsCL/P patient cohorts\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis (Irf6 mutant reduces SPECC1L expression) plus mouse mutant immunostaining, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"31943082\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Wild-type SPECC1L distributes evenly throughout the cytoplasm and colocalizes with both microtubules and filamentous actin. Mutant SPECC1L lacking CCD2 (SPECC1L-ΔCCD2) shows abnormal perinuclear accumulation with diminished microtubule overlap, demonstrating SPECC1L uses microtubule association for intracellular trafficking. CCD2 deletion results in gain-of-function: increased actin and non-muscle myosin II bundles displaced to the cell periphery, disrupting actomyosin organization and tissue fusion dynamics (exencephaly, cleft palate, omphalocele in homozygous mice).\",\n      \"method\": \"Mouse in-frame deletion alleles (Specc1lΔCCD2), immunofluorescence colocalization of SPECC1L with microtubules and F-actin, non-muscle myosin II staining, mouse embryo phenotypic analysis\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — structure-function mutagenesis (in-frame CCD2 deletion) combined with cell imaging and mouse in vivo phenotypes, multiple orthogonal readouts in single rigorous study\",\n      \"pmids\": [\"34302166\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"SPECC1L-deficient primary mouse embryonic palatal mesenchyme (MEPM) cells show reduced cell speed and defective coordinated (collective) cell movement in wound-repair assays. Activation of the PI3K-AKT pathway rescues both cell speed and directional guidance defects in Specc1l mutant MEPM cells, confirming SPECC1L modulates collective mesenchymal cell movement through PI3K-AKT signaling.\",\n      \"method\": \"Live-imaging wound-repair assays of primary MEPM cells from Specc1l mutant mice, pharmacological PI3K-AKT activation rescue\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — primary cell live-imaging plus pharmacological rescue, single lab, two orthogonal methods\",\n      \"pmids\": [\"33446878\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SPECC1L directly binds MYPT1 and forms a stable complex with the myosin phosphatase holoenzyme MYPT1/PP1β. SPECC1L can regulate the balance of MYPT1/PP1β distribution between microtubule and filamentous actin networks, suggesting it acts as a scaffold that traffics this phosphatase between cytoskeletal substrates.\",\n      \"method\": \"Co-immunoprecipitation, proximity biotinylation (BioID), direct binding assay, interactome comparison of SPECC1L and MYPT1\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — direct binding assay plus reciprocal co-IP and orthogonal proximity biotinylation, interactome overlap validation, multiple methods in single rigorous study\",\n      \"pmids\": [\"36634848\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SPECC1L associates with microtubules, filamentous actin, non-muscle myosin II (NMII), and membrane-associated components of adherens junctions, functioning as a cytoskeletal scaffolding protein. Syndromic SPECC1L mutations act through a gain-of-function mechanism to affect intra- and supra-cellular actin organization.\",\n      \"method\": \"Review/synthesis of multiple experimental findings (colocalization, co-IP, mouse models)\",\n      \"journal\": \"Biochemical Society transactions\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — consolidation of replicated experimental data from multiple papers and methods; review but citing primary experimental evidence\",\n      \"pmids\": [\"37345651\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SPECC1L is required for proper bipolar spindle assembly during mouse oocyte meiotic maturation. Specc1l knockdown in oocytes caused abnormal spindle morphology, misaligned chromosomes, decreased polar body extrusion, and reduced blastocyst formation. SPECC1L localizes to cytoplasm and germinal vesicle but not to the nucleolus-like body or chromatin.\",\n      \"method\": \"siRNA knockdown in mouse oocytes, immunofluorescence localization, live-imaging of spindle assembly and polar body extrusion\",\n      \"journal\": \"Reproduction (Cambridge, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA KD with defined cellular phenotype (spindle, chromosome alignment) plus direct localization, single lab\",\n      \"pmids\": [\"37698179\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Loss of SPECC1L specifically in cranial neural crest cells (Wnt1-Cre2 conditional KO) causes shortened primary cilia and increased Hedgehog (Hh) signaling (elevated GLI1) in cranial mesenchyme from E9.5, resulting in frontonasal dysplasia features. SPECC1L itself does not localize to cilia but regulates cilia length indirectly through F-actin regulation.\",\n      \"method\": \"Conditional Specc1l knockout (Wnt1-Cre2 × Specc1l-flox), GLI1 immunostaining, primary cilia length measurement, embryo phenotypic analysis\",\n      \"journal\": \"Frontiers in physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-type-specific conditional KO with mechanistic readouts (cilia length, Hh/GLI1 signaling), single lab\",\n      \"pmids\": [\"41657552\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SPECC1L loss leads to increased F-actin levels and shortened primary cilia. Depolymerizing F-actin in Specc1l mutant cells restored cilia length, establishing a causal inverse relationship between SPECC1L-regulated F-actin and cilia length. A genetic interaction between Specc1l and Thm1 (IFT-A component) was identified: compound/double heterozygotes show higher penetrance of cleft palate than Specc1l heterozygotes alone.\",\n      \"method\": \"F-actin depolymerization rescue of cilia length in Specc1l mutant cells, genetic compound heterozygote analysis (Specc1l × Thm1), cilia length measurement\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological rescue experiment plus genetic epistasis, single lab, preprint\",\n      \"pmids\": [\"41278885\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"The Drosophila SPECC1L homolog Split Discs (Spdi) co-localizes with non-muscle myosin II and actin (not microtubules as proposed for the mammalian protein). RNAi depletion of Spdi increases focal adhesion dynamics. Conserved point mutations analogous to human disease variants cause a further increase in focal adhesion dynamics beyond knockdown alone, suggesting disease mutations affect cell-matrix adhesion through NMII association.\",\n      \"method\": \"RNAi depletion in Drosophila cells, immunofluorescence colocalization with NMII/actin, focal adhesion dynamics assays, site-directed mutagenesis of disease-analogous residues\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi KD plus structure-function mutagenesis with defined cellular phenotype (focal adhesion dynamics), single lab, preprint ortholog study\",\n      \"pmids\": [\"40236004\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"An intragenic SPECC1L deletion encompassing exon 3 (containing the canonical start codon) leads to alternative start codon usage and protein truncation, demonstrating the N-terminal disordered region is required for normal SPECC1L translation initiation and function in craniofacial development.\",\n      \"method\": \"Functional overexpression assay of deletion construct, protein truncation analysis, Sanger sequencing\",\n      \"journal\": \"NPJ genomic medicine\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single overexpression assay demonstrating alternative start site usage, no in vivo or cellular rescue, single lab\",\n      \"pmids\": [\"41120295\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SPECC1L is a cytoskeletal scaffolding protein that associates with microtubules (via its CCD2 domain), filamentous actin, and adherens junction components; it forms a stable complex with the myosin phosphatase MYPT1/PP1β (which it can direct between microtubule and actin networks), modulates PI3K-AKT signaling to control adherens junction stability and collective cell movement, regulates actomyosin (non-muscle myosin II) organization and spindle assembly, and indirectly controls primary cilia length through F-actin levels—collectively making it a central regulator of tissue movement and fusion events during embryogenesis, particularly in cranial neural crest cell delamination and craniofacial morphogenesis.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SPECC1L is a cytoskeletal scaffolding protein that coordinates actin and microtubule networks to drive the tissue movement and fusion events of craniofacial morphogenesis, particularly cranial neural crest cell (CNCC) delamination and palatogenesis [#0, #1, #3]. It colocalizes with both microtubules and filamentous actin, using a second coiled-coil domain (CCD2) for microtubule association and intracellular trafficking; CCD2 deletion produces a gain-of-function state with excess actin and non-muscle myosin II bundles displaced to the cell periphery, disrupting actomyosin organization and producing exencephaly, cleft palate, and omphalocele in mice [#3]. SPECC1L directly binds MYPT1 and forms a stable complex with the myosin phosphatase holoenzyme MYPT1/PP1β, distributing this phosphatase between microtubule and actin networks [#5]. Functionally, SPECC1L restrains adherens junction stability—its loss increases β-catenin and E-cadherin junctional signal and impairs CNCC delamination—acting through PI3K-AKT signaling, since PI3K-AKT activation rescues both the junctional defects and the impaired collective movement of mutant palatal mesenchyme cells [#1, #4]. In CNCCs, SPECC1L additionally limits F-actin levels to control primary cilium length and thereby Hedgehog signaling, without itself localizing to cilia [#8, #9]. SPECC1L is also required for bipolar spindle assembly and chromosome alignment during oocyte meiotic maturation [#7]. Genetically, SPECC1L lies downstream of IRF6 in palatogenesis, and disease-associated mutations cluster in CCD2 and the calponin homology domains, acting through a gain-of-function mechanism to perturb actin organization [#2, #6].\"\n,\n  \"teleology\": [\n    {\n      \"year\": 2011,\n      \"claim\": \"Established SPECC1L as a dual cytoskeletal-associated protein whose loss disrupts actin reorganization, adhesion, and migration, framing it as a candidate regulator of cell movement.\",\n      \"evidence\": \"Immunofluorescence colocalization with tubulin and actin, siRNA knockdown adhesion/migration assays in mammalian cells, Drosophila knockdown phenocopying integrin pathway mutants\",\n      \"pmids\": [\"21703590\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No molecular partners identified\", \"Mechanism linking SPECC1L to integrin signaling unresolved\", \"No structure-function mapping of domains\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Placed SPECC1L mechanistically upstream of adherens junction stability and PI3K-AKT signaling, explaining the CNCC delamination defect underlying craniofacial disease.\",\n      \"evidence\": \"siRNA knockdown with immunostaining/EM, mouse gene-trap knockout with CNCC lineage analysis, reciprocal pharmacological PI3K-AKT inhibition and activation rescue\",\n      \"pmids\": [\"26787558\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct molecular link between SPECC1L and PI3K-AKT components not defined\", \"Whether AJ effect is via cytoskeleton or signaling not separated\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Defined where disease mutations cluster (CCD2 and calponin homology domains) and their effect on microtubule association, and positioned SPECC1L downstream of IRF6 in palatogenesis.\",\n      \"evidence\": \"Mouse truncation alleles, palatal shelf immunostaining, Irf6 mutant analysis, nsCL/P patient cohort sequencing\",\n      \"pmids\": [\"31943082\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How IRF6 regulates SPECC1L expression unknown\", \"Functional consequence of lost microtubule association not yet tied to phenotype\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Resolved CCD2 as the microtubule-trafficking determinant and showed its deletion is a gain-of-function that displaces actomyosin bundles, mechanistically connecting domain loss to actin/NMII dysregulation and tissue fusion failure.\",\n      \"evidence\": \"Mouse in-frame Specc1lΔCCD2 alleles, immunofluorescence colocalization, NMII staining, embryo phenotyping\",\n      \"pmids\": [\"34302166\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of the gain-of-function actin effect not defined\", \"Cargo trafficked along microtubules not identified at this stage\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Connected the cellular adhesion/migration defect to PI3K-AKT by showing pathway activation rescues collective movement of primary mutant mesenchyme cells.\",\n      \"evidence\": \"Live-imaging wound-repair assays of primary MEPM cells from Specc1l mutants with pharmacological PI3K-AKT activation rescue\",\n      \"pmids\": [\"33446878\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct biochemical link between SPECC1L and PI3K-AKT still missing\", \"How cytoskeletal scaffolding feeds into directional guidance unclear\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified the first direct molecular partner, MYPT1/PP1β myosin phosphatase, and proposed SPECC1L as a scaffold that traffics the phosphatase between microtubule and actin networks—providing a biochemical mechanism for actomyosin regulation.\",\n      \"evidence\": \"Co-immunoprecipitation, BioID proximity biotinylation, direct binding assay, SPECC1L/MYPT1 interactome comparison\",\n      \"pmids\": [\"36634848\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether phosphatase redistribution drives the craniofacial phenotype not tested in vivo\", \"Substrates of the redistributed phosphatase not enumerated\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended SPECC1L function to meiotic spindle assembly, indicating its cytoskeletal scaffolding role operates beyond craniofacial tissues.\",\n      \"evidence\": \"siRNA knockdown in mouse oocytes, immunofluorescence localization, live-imaging of spindle assembly and polar body extrusion\",\n      \"pmids\": [\"37698179\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism in spindle assembly unknown\", \"Whether MYPT1/PP1β complex participates in oocyte phenotype untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Linked SPECC1L to primary cilium length and Hedgehog signaling in CNCCs via F-actin control, establishing a causal F-actin–cilia axis and a genetic interaction with the IFT-A component THM1.\",\n      \"evidence\": \"Wnt1-Cre2 conditional knockout with GLI1 immunostaining and cilia measurements; F-actin depolymerization rescue and Specc1l×Thm1 compound heterozygote analysis (one preprint)\",\n      \"pmids\": [\"41657552\", \"41278885\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How F-actin level controls ciliogenesis mechanistically not defined\", \"THM1 interaction is genetic, not biochemical\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Tested the conserved Drosophila ortholog Spdi, supporting NMII/actin association and a gain-of-function effect of disease-analogous mutations on focal adhesion dynamics.\",\n      \"evidence\": \"RNAi depletion in Drosophila cells, NMII/actin colocalization, focal adhesion dynamics assays, site-directed mutagenesis (preprint)\",\n      \"pmids\": [\"40236004\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Ortholog did not colocalize with microtubules, leaving cross-species mechanism partly divergent\", \"Preprint, not peer-reviewed\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Indicated the N-terminal disordered region is needed for correct translation initiation, since an exon 3 deletion forces alternative start codon usage and protein truncation.\",\n      \"evidence\": \"Functional overexpression assay of a deletion construct, protein truncation analysis, Sanger sequencing\",\n      \"pmids\": [\"41120295\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single overexpression assay with no cellular or in vivo rescue\", \"Functional consequence of the truncated protein not characterized\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How SPECC1L mechanistically couples its cytoskeletal scaffolding and MYPT1/PP1β trafficking to PI3K-AKT signaling, adherens junction control, and F-actin/cilia regulation within a single unified pathway remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct biochemical link between SPECC1L and PI3K-AKT identified\", \"Whether the MYPT1/PP1β complex mediates the AJ, cilia, and spindle phenotypes untested\", \"Structural basis of CCD2/CH-domain cytoskeletal binding undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0, 3, 5, 6]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [5, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [0, 3, 6]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [3, 7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [1, 2, 3, 8]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 4, 8]}\n    ],\n    \"complexes\": [\"MYPT1/PP1β myosin phosphatase holoenzyme\"],\n    \"partners\": [\"MYPT1\", \"PPP1CB\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}