{"gene":"SMOC1","run_date":"2026-06-10T07:46:36","timeline":{"discoveries":[{"year":2002,"finding":"SMOC-1 is a secreted modular glycoprotein with a calcium-dependent conformation, containing an EF-hand calcium-binding domain homologous to BM-40, two thyroglobulin-like domains, a follistatin-like domain, and a novel domain. It localizes to basement membranes and other extracellular matrices, as demonstrated by immunofluorescence and immunogold electron microscopy in kidney, skeletal muscle, and zona pellucida.","method":"Recombinant expression in human cells, Northern blot, RT-PCR, immunoblot, immunofluorescence, immunogold electron microscopy","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (recombinant expression, structural characterization, direct localization by immunogold EM) in foundational characterization paper","pmids":["12130637"],"is_preprint":false},{"year":2009,"finding":"Xenopus SMOC-1 acts as a BMP antagonist downstream of the BMP receptor, distinct from extracellular ligand-binding antagonists like noggin. It antagonizes BMP activity even in the presence of a constitutively active BMP receptor, and the mechanism involves MAPK-mediated phosphorylation of the Smad linker region. Morpholino-based loss-of-function reveals SMOC-1 is essential for postgastrulation development.","method":"Gain-of-function assays in Xenopus embryos, constitutively active BMP receptor constructs, antisense morpholino knockdown, MAPK pathway analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal approaches (gain-of-function, constitutively active receptor epistasis, morpholino loss-of-function) in a single rigorous study establishing downstream receptor mechanism","pmids":["19414592"],"is_preprint":false},{"year":2010,"finding":"SMOC1 is required for ocular and limb development. Smoc1 null mice exhibit aplasia/hypoplasia of optic nerves, hypoplastic fibula, bowed tibia, and syndactyly. Soft tissue syndactyly results from inhibited apoptosis linked to disturbed BMP signaling gene expression in interdigital mesenchyme.","method":"Smoc1 null mouse generation, histological and phenotypic analysis, expression analysis of BMP signaling genes in interdigital mesenchyme","journal":"American journal of human genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean knockout mouse with specific cellular phenotype (inhibited apoptosis) linked to BMP pathway gene expression changes, replicated across multiple families","pmids":["21194678"],"is_preprint":false},{"year":2010,"finding":"SMOC1 knockdown significantly inhibited mineralization and expression of osteoblast differentiation markers in bone marrow-derived mesenchymal stem cells, while SMOC1 overexpression increased osteoblast differentiation-related gene expression, identifying SMOC1 as a regulator of osteoblast differentiation.","method":"shRNA knockdown, cDNA overexpression, osteoblast differentiation assays (mineralization, marker gene expression) in BMSCs","journal":"Journal of proteome research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — bidirectional perturbation (KD and OE) with defined cellular phenotype, single lab","pmids":["20359165"],"is_preprint":false},{"year":2011,"finding":"SMOC-1 directly interacts with tenascin-C, as confirmed by co-immunoprecipitation and Surface Plasmon Resonance Spectroscopy (KD = 2.59×10⁻⁹ M). This binding is reduced in the presence of EDTA, indicating calcium dependence. SMOC1 can counteract the chemo-attractive effect of tenascin-C on glioma cells.","method":"Tenascin-C affinity column purification, mass spectrometry, co-immunoprecipitation, Surface Plasmon Resonance Spectroscopy, cell migration assay","journal":"Matrix biology : journal of the International Society for Matrix Biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — quantitative binding kinetics by SPR plus co-IP confirmation plus functional cell migration assay, single lab but multiple orthogonal methods","pmids":["21349332"],"is_preprint":false},{"year":2011,"finding":"SMOC-1 functions as a BMP antagonist during mammalian limb and eye development. Loss of SMOC-1 (gene-trap reducing mRNA to ~10% of wild-type) causes hindlimb post-axial oligosyndactyly, coloboma, and cleft palate, phenocopying human ophthalmo-acromelic syndrome. Missense mutations are located in the second Thyroglobulin Type-1 domain.","method":"Gene-trap mouse mutant (Smoc1tm1a), phenotypic analysis, mutation mapping to protein domains","journal":"PLoS genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — hypomorphic gene-trap allele with dose-dependent penetrant phenotype, multiple families with mutations in specific protein domain, independent replication of BMP antagonist role","pmids":["21750680"],"is_preprint":false},{"year":2013,"finding":"SMOC-1 binds heparin and heparan sulfate (but not chondroitin sulfate or dermatan sulfate) via a basic region in the EC domain consisting of two antiparallel alpha helices. Heparin-binding residues in both helices must be replaced to abolish binding. The heparin-binding activity of the EC domain mediates adhesion of epithelial HaCaT cells to SMOC-1; heparin-binding-impaired mutants failed to support cell adhesion.","method":"Size-exclusion chromatography, intrinsic tryptophan fluorescence measurements, site-directed mutagenesis of heparin-binding residues, cell adhesion assay","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1 / Moderate — quantitative binding assays plus mutagenesis plus functional cell adhesion readout, single lab with multiple orthogonal methods","pmids":["23437253"],"is_preprint":false},{"year":2015,"finding":"SMOC1 associates with endoglin (an endothelium-specific auxiliary TGF-β receptor) and acts as a negative regulator of ALK5/SMAD2 signaling, thereby promoting TGF-β signaling via ALK1 and endothelial cell activation. SMOC1 downregulation effects on SMAD2 phosphorylation were abolished by endoglin knockdown. SMOC1 expression is regulated by hypoxia via miR-223 downregulation.","method":"siRNA silencing, co-immunoprecipitation, proximity ligation assay, immunohistochemistry, in vitro angiogenesis assays, aortic ring sprouting, postnatal retinal angiogenesis in SMOC1+/- mice","journal":"Cardiovascular research","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP plus proximity ligation assay plus epistasis (endoglin KD rescuing SMOC1 KD effect) plus in vivo validation in heterozygous mice","pmids":["25750188"],"is_preprint":false},{"year":2018,"finding":"C. elegans SMOC-1 acts cell-nonautonomously as a positive modulator of BMP signaling. It antagonizes the glypican LON-2 and acts through the BMP ligand DBL-1. Double-mutant analysis placed SMOC-1 upstream of DBL-1/BMP. Human SMOC1 and SMOC2 each partially rescue the smoc-1(0) mutant phenotype, demonstrating evolutionary conservation of the BMP-modulatory function.","method":"smoc-1 loss-of-function mutant analysis, smoc-1 overexpression with BMP reporter, double-mutant epistasis analysis, cell-specific rescue experiments, human SMOC1/SMOC2 cross-species rescue","journal":"Genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with double mutants, cell-nonautonomy established by tissue-specific rescue, cross-species rescue with human protein confirms conservation","pmids":["30518528"],"is_preprint":false},{"year":2018,"finding":"SMOC1 silencing suppresses angiotensin II-induced myocardial fibroblast fibrosis by affecting the BMP2/Smad signaling pathway, reducing ROS content, oxidative stress, and fibrosis-associated protein expression.","method":"siRNA knockdown, Cell Counting Kit-8 viability assay, flow cytometry (ROS), ELISA, Western blot, RT-qPCR in myocardial fibroblasts","journal":"Oncology letters","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — KD with defined phenotype and pathway (BMP2/Smad), single lab, multiple readouts but no direct binding or reconstitution","pmids":["30127878"],"is_preprint":false},{"year":2020,"finding":"SMOC1 is a glucose-responsive hepatokine that improves glycemic control by inhibiting cAMP-PKA-CREB signaling in the liver, leading to decreased gluconeogenic gene expression and suppression of hepatic glucose output. Acute IP administration improved insulin sensitivity without changing insulin secretion; liver-specific overexpression and stabilized SMOC1-Fc fusion protein induced durable improvements in db/db mice.","method":"Acute IP administration in mice, liver-specific overexpression, SMOC1-Fc fusion protein weekly injections in db/db mice, cAMP-PKA-CREB pathway analysis, gluconeogenic gene expression assays, glucose tolerance/insulin sensitivity tests","journal":"Science translational medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple in vivo models (acute dosing, liver OE, fusion protein), mechanistic pathway (cAMP-PKA-CREB) identified, multiple orthogonal readouts in a single rigorous study","pmids":["32878981"],"is_preprint":false},{"year":2020,"finding":"Fasting-induced upregulation of SMOC1 in endothelial cells promotes angiogenesis. Downregulation of SMOC1 attenuated fasting/refeeding-induced pro-angiogenic effects (proliferation, migration, tube formation), establishing SMOC1 as a mediator of fasting-induced angiogenesis.","method":"Transcriptome sequencing, siRNA knockdown, in vitro angiogenesis assays (proliferation, migration, tube formation), immunofluorescent staining in wound models","journal":"Theranostics","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — KD with specific angiogenic phenotype confirmed by multiple in vitro assays and in vivo staining, single lab","pmids":["32206122"],"is_preprint":false},{"year":2021,"finding":"Smoc1 and Smoc2 are direct transcriptional targets of Runx2 and are required for bone formation. Smoc1 KO mice display absent fibula formation; Smoc1/Smoc2 double KO mice show absent skull, shortened tibiae, absent fibulae, and impaired endochondral bone formation. Smoc1 or Smoc2 knockdown inhibits osteoblastogenesis in vitro.","method":"RNA sequencing to identify Runx2 targets, Smoc1 KO mice, Smoc1/Smoc2 double KO mice, in vitro knockdown and osteoblastogenesis assays","journal":"Communications biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — RNA-seq target identification plus single and double KO mouse models with specific skeletal phenotypes, plus in vitro KD confirming cell-autonomous role","pmids":["34667264"],"is_preprint":false},{"year":2021,"finding":"IL-4 and IL-13 inhibit SMOC1 expression in primary human keratinocytes. SMOC1 siRNA knockdown inhibited epidermal differentiation markers and increased the amplitude of Ca2+ peak response, demonstrating that SMOC1 modulates Ca2+-induced keratinocyte differentiation signals.","method":"siRNA knockdown of SMOC1, real-time Ca2+ influx measurement by flow cytometry and microscopy, expression analysis of differentiation markers","journal":"The Journal of investigative dermatology","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — KD with specific Ca2+ transport and differentiation phenotype, single lab, two orthogonal readouts","pmids":["33484701"],"is_preprint":false},{"year":2023,"finding":"C. elegans SMOC-1 directly binds both LON-2/glypican (via the EC domain) and the mature domain of DBL-1/BMP (requiring full-length SMOC-1), and can simultaneously bind both. SMOC-1 functions negatively in a LON-2/glypican-dependent manner and positively in a DBL-1/BMP-dependent manner to regulate BMP signaling. Drosophila and vertebrate SMOC proteins can also bind mature BMP dimers in silico.","method":"Biochemical binding assays (Co-IP, pulldown), structural modeling, molecular genetics (domain-specific mutants, double mutants), in vivo BMP reporter assays","journal":"PLoS biology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — direct biochemical binding assays plus in vivo genetic epistasis plus domain-specific mutants establishing dual mechanism, replicated from preprint with additional data","pmids":["37590248"],"is_preprint":false},{"year":2024,"finding":"SMOC1 is regulated by androgen (testosterone via the androgen receptor) in gubernacular cells, and SMOC1 in turn promotes gubernacular cell proliferation and expression of myogenic regulatory factors Pax7 and Myf5. siRNA knockdown of Smoc1 abolished testosterone-induced Pax7 and Myf5 upregulation, and exogenous SMOC1 rescued this effect, placing SMOC1 downstream of androgen signaling in gubernaculum development.","method":"Gene expression analysis in Lhcgr KO mice, testosterone administration with/without flutamide (androgen receptor antagonist), siRNA knockdown, in vitro gubernacular cell proliferation and myogenic differentiation assays","journal":"Asian journal of andrology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic model plus pharmacological epistasis plus KD/rescue in vitro, single lab","pmids":["39119686"],"is_preprint":false},{"year":2025,"finding":"SMOC1 expression in β-cells is increased in type 2 diabetes and drives β-cell dedifferentiation. Enhanced SMOC1 expression in β-cells decreased insulin expression and secretion and increased β-cell dedifferentiation markers.","method":"Single-cell and single-nucleus RNA-seq, RNA velocity, PAGA/cell trajectory inference, SMOC1 overexpression in β-cells with insulin secretion and dedifferentiation marker assays","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — trajectory inference plus functional overexpression assay with defined phenotype (decreased insulin secretion, increased dedifferentiation markers), single lab","pmids":["41057332"],"is_preprint":false}],"current_model":"SMOC1 is a secreted modular calcium-binding matricellular glycoprotein that localizes to basement membranes and extracellular matrices, where it modulates BMP signaling (acting downstream of the BMP receptor via MAPK-Smad linker phosphorylation, and by simultaneously binding BMP ligands and glypican co-receptors), interacts with tenascin-C and endoglin to regulate TGF-β/ALK5 signaling, binds heparin/heparan sulfate through its EC domain to mediate cell adhesion, functions as a glucose-responsive hepatokine suppressing cAMP-PKA-CREB-driven gluconeogenesis, acts downstream of Runx2 to promote osteoblast differentiation and skeletal morphogenesis, is regulated by androgen to support gubernaculum development, and when aberrantly expressed in β-cells drives dedifferentiation and impairs insulin secretion."},"narrative":{"mechanistic_narrative":"SMOC1 is a secreted, calcium-binding matricellular glycoprotein that deposits in basement membranes and extracellular matrices and acts as a modulator of BMP and TGF-β signaling during development and tissue homeostasis [PMID:12130637, PMID:19414592]. Its multidomain architecture—an EF-hand calcium-binding region, thyroglobulin-like domains, a follistatin-like domain, and an extracellular calcium-binding (EC) domain—supports a calcium-dependent conformation and matrix localization [PMID:12130637]. SMOC1 modulates BMP signaling through dual mechanisms: it acts downstream of the BMP receptor via MAPK-dependent phosphorylation of the Smad linker region [PMID:19414592], and it directly binds both mature BMP ligand dimers and the glypican co-receptor, enabling it to function negatively in a glypican-dependent manner and positively in a BMP-ligand-dependent manner [PMID:37590248]. Through these activities SMOC1 is essential for ocular, limb, and skeletal development, with loss causing optic and skeletal malformations that phenocopy ophthalmo-acromelic syndrome [PMID:21194678, PMID:21750680]. SMOC1 is a direct transcriptional target of Runx2 and drives osteoblast differentiation and endochondral bone formation [PMID:20359165, PMID:34667264]. The EC domain binds heparin and heparan sulfate through a basic helical region to mediate cell adhesion [PMID:23437253], and SMOC1 binds tenascin-C and associates with endoglin to negatively regulate ALK5/SMAD2 signaling in endothelial cells [PMID:21349332, PMID:25750188]. Beyond development, SMOC1 functions as a glucose-responsive hepatokine that suppresses cAMP-PKA-CREB-driven gluconeogenesis to improve glycemic control [PMID:32878981], whereas its aberrant expression in β-cells drives dedifferentiation and impairs insulin secretion [PMID:41057332].","teleology":[{"year":2002,"claim":"Established SMOC1 as a secreted, calcium-dependent modular matricellular glycoprotein and defined its domain architecture and matrix localization, providing the structural foundation for all later functional work.","evidence":"Recombinant expression, structural characterization, and immunogold EM localization in kidney, muscle, and zona pellucida","pmids":["12130637"],"confidence":"High","gaps":["No binding partners or signaling function identified at this stage","Function of individual domains not yet assigned"]},{"year":2009,"claim":"Defined SMOC1 as a BMP antagonist acting downstream of the BMP receptor rather than by sequestering ligand, distinguishing it mechanistically from classical extracellular antagonists.","evidence":"Gain-of-function and constitutively active receptor epistasis plus morpholino knockdown in Xenopus, with MAPK-Smad linker analysis","pmids":["19414592"],"confidence":"High","gaps":["Direct molecular target of SMOC1 in the receptor-downstream cascade not identified","Whether the mechanism is conserved in mammals untested here"]},{"year":2010,"claim":"Linked SMOC1 loss to specific ocular and limb developmental defects in mammals and connected the syndactyly phenotype to disrupted BMP-dependent interdigital apoptosis.","evidence":"Smoc1 null mouse phenotyping with BMP signaling gene expression analysis in interdigital mesenchyme","pmids":["21194678"],"confidence":"High","gaps":["Molecular intermediary between SMOC1 and apoptotic BMP genes not defined","Tissue-autonomy of the requirement not resolved"]},{"year":2010,"claim":"Identified SMOC1 as a bidirectional regulator of osteoblast differentiation, extending its role to skeletal cell fate.","evidence":"shRNA knockdown and overexpression with mineralization and marker assays in BMSCs","pmids":["20359165"],"confidence":"Medium","gaps":["Single lab, no in vivo skeletal validation at this stage","Mechanistic link to a defined pathway not established"]},{"year":2011,"claim":"Identified the first direct binding partner, tenascin-C, in a calcium-dependent interaction with functional consequences for cell migration.","evidence":"Affinity purification, mass spectrometry, Co-IP, SPR kinetics, and glioma migration assay","pmids":["21349332"],"confidence":"High","gaps":["Binding domain on SMOC1 not mapped","Physiological context of the SMOC1-tenascin-C axis unresolved"]},{"year":2011,"claim":"Confirmed in mammals that SMOC1 is a BMP antagonist essential for limb and eye development and tied human ophthalmo-acromelic syndrome mutations to a specific thyroglobulin domain.","evidence":"Hypomorphic gene-trap mouse with dose-dependent phenotype and human mutation mapping","pmids":["21750680"],"confidence":"High","gaps":["Functional consequence of the thyroglobulin domain mutations on protein activity not biochemically tested","Mechanism of antagonism not resolved here"]},{"year":2013,"claim":"Mapped a heparin/heparan-sulfate-binding activity to a basic helical region of the EC domain and showed this activity mediates cell adhesion.","evidence":"Size-exclusion chromatography, tryptophan fluorescence, site-directed mutagenesis, and HaCaT cell adhesion assay","pmids":["23437253"],"confidence":"High","gaps":["Cell-surface heparan sulfate proteoglycan partner not identified","Relationship between adhesion activity and BMP modulation unclear"]},{"year":2015,"claim":"Extended SMOC1 function to TGF-β signaling by showing it associates with endoglin and negatively regulates ALK5/SMAD2, promoting ALK1-driven endothelial activation.","evidence":"siRNA, reciprocal Co-IP, proximity ligation assay, endoglin-knockdown epistasis, and angiogenesis assays in SMOC1+/- mice","pmids":["25750188"],"confidence":"High","gaps":["Structural basis of the SMOC1-endoglin interaction not defined","How SMOC1 discriminates between ALK1 and ALK5 not resolved"]},{"year":2018,"claim":"Demonstrated evolutionary conservation and cell-nonautonomy of SMOC1's BMP-modulatory role and placed it genetically relative to glypican and BMP ligand.","evidence":"C. elegans loss-of-function, double-mutant epistasis, tissue-specific rescue, and human SMOC1/SMOC2 cross-species rescue","pmids":["30518528"],"confidence":"High","gaps":["Direct binding interactions not yet demonstrated at this stage","Whether positive and negative effects use the same molecular interaction unknown"]},{"year":2018,"claim":"Connected SMOC1 to pathological fibrosis via the BMP2/Smad pathway and oxidative stress in cardiac fibroblasts.","evidence":"siRNA knockdown with ROS, ELISA, Western blot, and qPCR readouts in myocardial fibroblasts","pmids":["30127878"],"confidence":"Medium","gaps":["No direct binding or reconstitution","Single-lab, in vitro only"]},{"year":2020,"claim":"Revealed an unexpected metabolic role: SMOC1 acts as a glucose-responsive hepatokine that suppresses gluconeogenesis through cAMP-PKA-CREB inhibition.","evidence":"Acute IP dosing, liver-specific overexpression, and SMOC1-Fc fusion therapy in db/db mice with pathway and glucose-handling assays","pmids":["32878981"],"confidence":"High","gaps":["Receptor or surface target mediating the hepatokine effect not identified","Mechanistic link between matrix/BMP roles and metabolic signaling unresolved"]},{"year":2020,"claim":"Implicated SMOC1 as a mediator of fasting-induced angiogenesis in endothelial cells.","evidence":"Transcriptome sequencing, siRNA knockdown, and in vitro/in vivo angiogenesis assays","pmids":["32206122"],"confidence":"Medium","gaps":["Signaling pathway downstream of SMOC1 in this context not defined","Single lab"]},{"year":2021,"claim":"Placed SMOC1 in a defined transcriptional hierarchy as a direct Runx2 target required for bone formation, with redundancy with SMOC2.","evidence":"RNA-seq target identification, single and Smoc1/Smoc2 double KO mice, and in vitro osteoblastogenesis knockdown","pmids":["34667264"],"confidence":"High","gaps":["Molecular effector by which SMOC1 promotes osteoblastogenesis not defined","Extent of functional overlap versus distinct roles of SMOC1 and SMOC2 unresolved"]},{"year":2021,"claim":"Showed SMOC1 modulates calcium-induced keratinocyte differentiation and is suppressed by type 2 inflammatory cytokines.","evidence":"siRNA knockdown, real-time Ca2+ imaging, and differentiation marker analysis in primary keratinocytes","pmids":["33484701"],"confidence":"Medium","gaps":["Mechanism linking SMOC1 to Ca2+ flux not defined","Single lab"]},{"year":2023,"claim":"Resolved the dual-mode mechanism by demonstrating that SMOC1 directly binds both glypican (via the EC domain) and mature BMP ligand simultaneously, explaining its opposing negative and positive effects on BMP signaling.","evidence":"Co-IP, pulldown, domain-specific mutants, structural modeling, and in vivo BMP reporter assays in C. elegans","pmids":["37590248"],"confidence":"High","gaps":["Stoichiometry and structure of the SMOC1-BMP-glypican complex not solved","Whether mammalian SMOC1 uses the identical dual mechanism in vivo not directly tested"]},{"year":2024,"claim":"Positioned SMOC1 downstream of androgen receptor signaling in gubernaculum development, driving myogenic gene expression and cell proliferation.","evidence":"Lhcgr KO mice, testosterone/flutamide pharmacological epistasis, and siRNA knockdown/rescue in gubernacular cells","pmids":["39119686"],"confidence":"Medium","gaps":["Direct molecular mechanism by which SMOC1 induces Pax7/Myf5 not defined","Single lab"]},{"year":2025,"claim":"Identified pathological SMOC1 upregulation in β-cells as a driver of dedifferentiation and impaired insulin secretion in type 2 diabetes.","evidence":"Single-cell/single-nucleus RNA-seq, trajectory inference, and SMOC1 overexpression with insulin secretion and dedifferentiation marker assays","pmids":["41057332"],"confidence":"Medium","gaps":["Signaling pathway mediating β-cell dedifferentiation by SMOC1 not defined","Causal role in vivo not established"]},{"year":null,"claim":"Whether the single-protein activities—BMP/glypican binding, heparin-mediated adhesion, endoglin/TGF-β regulation, and hepatokine signaling—are unified by a common biochemical mechanism, and what cell-surface receptor transduces the metabolic effect, remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No receptor identified for the hepatokine/metabolic function","No structure of any SMOC1-partner complex","Integration of developmental and metabolic roles unexplained"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[1,7,14]},{"term_id":"GO:0098631","term_label":"cell adhesion mediator activity","supporting_discovery_ids":[6]}],"localization":[{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[0,10]},{"term_id":"GO:0031012","term_label":"extracellular matrix","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,7,14]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[2,5,12]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[10]},{"term_id":"R-HSA-1474244","term_label":"Extracellular matrix organization","supporting_discovery_ids":[0,6]}],"complexes":[],"partners":["TNC","ENG","DBL-1/BMP","LON-2/GLYPICAN"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9H4F8","full_name":"SPARC-related modular calcium-binding protein 1","aliases":["Secreted modular calcium-binding protein 1","SMOC-1"],"length_aa":434,"mass_kda":48.2,"function":"Plays essential roles in both eye and limb development. Probable regulator of osteoblast differentiation","subcellular_location":"Secreted, extracellular space, extracellular matrix, basement membrane","url":"https://www.uniprot.org/uniprotkb/Q9H4F8/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SMOC1","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/SMOC1","total_profiled":1310},"omim":[{"mim_id":"608488","title":"SPARC-RELATED MODULAR CALCIUM-BINDING PROTEIN 1; SMOC1","url":"https://www.omim.org/entry/608488"},{"mim_id":"206920","title":"MICROPHTHALMIA WITH LIMB ANOMALIES; MLA","url":"https://www.omim.org/entry/206920"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Uncertain","locations":[{"location":"Plasma membrane","reliability":"Uncertain"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"brain","ntpm":62.5},{"tissue":"liver","ntpm":58.0}],"url":"https://www.proteinatlas.org/search/SMOC1"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q9H4F8","domains":[{"cath_id":"3.30.60.30","chopping":"49-91","consensus_level":"medium","plddt":82.4991,"start":49,"end":91},{"cath_id":"4.10.800.10","chopping":"109-151","consensus_level":"high","plddt":84.2495,"start":109,"end":151},{"cath_id":"4.10.800.10","chopping":"250-298","consensus_level":"medium","plddt":87.7951,"start":250,"end":298},{"cath_id":"-","chopping":"301-340_357-434","consensus_level":"medium","plddt":84.4651,"start":301,"end":434}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H4F8","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H4F8-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H4F8-F1-predicted_aligned_error_v6.png","plddt_mean":73.31},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SMOC1","jax_strain_url":"https://www.jax.org/strain/search?query=SMOC1"},"sequence":{"accession":"Q9H4F8","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9H4F8.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9H4F8/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H4F8"}},"corpus_meta":[{"pmid":"12130637","id":"PMC_12130637","title":"Characterization of SMOC-1, a novel modular calcium-binding protein in basement membranes.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12130637","citation_count":101,"is_preprint":false},{"pmid":"21194678","id":"PMC_21194678","title":"SMOC1 is essential for ocular and limb development in humans and mice.","date":"2010","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21194678","citation_count":96,"is_preprint":false},{"pmid":"20359165","id":"PMC_20359165","title":"Secretome analysis of human BMSCs and identification of SMOC1 as an important ECM protein in osteoblast differentiation.","date":"2010","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/20359165","citation_count":93,"is_preprint":false},{"pmid":"21750680","id":"PMC_21750680","title":"Loss of the BMP antagonist, SMOC-1, causes Ophthalmo-acromelic (Waardenburg Anophthalmia) syndrome in humans and mice.","date":"2011","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21750680","citation_count":76,"is_preprint":false},{"pmid":"25750188","id":"PMC_25750188","title":"Role of secreted modular calcium-binding protein 1 (SMOC1) in transforming growth factor β signalling and angiogenesis.","date":"2015","source":"Cardiovascular research","url":"https://pubmed.ncbi.nlm.nih.gov/25750188","citation_count":66,"is_preprint":false},{"pmid":"21194680","id":"PMC_21194680","title":"Mutations in the SPARC-related modular calcium-binding protein 1 gene, SMOC1, cause waardenburg anophthalmia syndrome.","date":"2010","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21194680","citation_count":65,"is_preprint":false},{"pmid":"19842175","id":"PMC_19842175","title":"Developmental expression of Smoc1 and Smoc2 suggests potential roles in fetal gonad and reproductive tract differentiation.","date":"2009","source":"Developmental dynamics : an official publication of the American Association of Anatomists","url":"https://pubmed.ncbi.nlm.nih.gov/19842175","citation_count":51,"is_preprint":false},{"pmid":"32878981","id":"PMC_32878981","title":"SMOC1 is a glucose-responsive hepatokine and therapeutic target for glycemic control.","date":"2020","source":"Science translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/32878981","citation_count":47,"is_preprint":false},{"pmid":"32206122","id":"PMC_32206122","title":"Fasting before or after wound injury accelerates wound healing through the activation of pro-angiogenic SMOC1 and SCG2.","date":"2020","source":"Theranostics","url":"https://pubmed.ncbi.nlm.nih.gov/32206122","citation_count":45,"is_preprint":false},{"pmid":"21349332","id":"PMC_21349332","title":"SMOC1 is a tenascin-C interacting protein over-expressed in brain tumors.","date":"2011","source":"Matrix biology : journal of the International Society for Matrix Biology","url":"https://pubmed.ncbi.nlm.nih.gov/21349332","citation_count":43,"is_preprint":false},{"pmid":"23263445","id":"PMC_23263445","title":"Genetic association suggests that SMOC1 mediates between prenatal sex hormones and digit ratio.","date":"2012","source":"Human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/23263445","citation_count":42,"is_preprint":false},{"pmid":"19414592","id":"PMC_19414592","title":"Xenopus SMOC-1 Inhibits bone morphogenetic protein signaling downstream of receptor binding and is essential for postgastrulation development in Xenopus.","date":"2009","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19414592","citation_count":36,"is_preprint":false},{"pmid":"34667264","id":"PMC_34667264","title":"Smoc1 and Smoc2 regulate bone formation as downstream molecules of Runx2.","date":"2021","source":"Communications 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and IL-13 Cytokines Interfere with Ca2+ Mobilization in Primary Human Keratinocytes.","date":"2021","source":"The Journal of investigative dermatology","url":"https://pubmed.ncbi.nlm.nih.gov/33484701","citation_count":17,"is_preprint":false},{"pmid":"30518528","id":"PMC_30518528","title":"The Caenorhabditis elegans SMOC-1 Protein Acts Cell Nonautonomously To Promote Bone Morphogenetic Protein Signaling.","date":"2018","source":"Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/30518528","citation_count":13,"is_preprint":false},{"pmid":"30127878","id":"PMC_30127878","title":"SMOC1 silencing suppresses the angiotensin II-induced myocardial fibrosis of mouse myocardial fibroblasts via affecting the BMP2/Smad pathway.","date":"2018","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/30127878","citation_count":13,"is_preprint":false},{"pmid":"28807869","id":"PMC_28807869","title":"A novel mutation in SMOC1 and variable phenotypic expression in two patients with Waardenburg anophthalmia syndrome.","date":"2017","source":"European journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/28807869","citation_count":11,"is_preprint":false},{"pmid":"28085523","id":"PMC_28085523","title":"A novel homozygous variant in the SMOC1 gene underlying Waardenburg anophthalmia syndrome.","date":"2017","source":"Ophthalmic genetics","url":"https://pubmed.ncbi.nlm.nih.gov/28085523","citation_count":9,"is_preprint":false},{"pmid":"18042303","id":"PMC_18042303","title":"Characterization of Smoc-1 uncovers two transcript variants showing differential tissue and age specific expression in Bubalus bubalis.","date":"2007","source":"BMC genomics","url":"https://pubmed.ncbi.nlm.nih.gov/18042303","citation_count":9,"is_preprint":false},{"pmid":"30445150","id":"PMC_30445150","title":"A fetal case of microphthalmia and limb anomalies with abnormal neuronal migration associated with SMOC1 biallelic variants.","date":"2018","source":"European journal of medical 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communications","url":"https://pubmed.ncbi.nlm.nih.gov/41057332","citation_count":5,"is_preprint":false},{"pmid":"37590248","id":"PMC_37590248","title":"SMOC-1 interacts with both BMP and glypican to regulate BMP signaling in C. elegans.","date":"2023","source":"PLoS biology","url":"https://pubmed.ncbi.nlm.nih.gov/37590248","citation_count":5,"is_preprint":false},{"pmid":"38429655","id":"PMC_38429655","title":"Downregulation of SMOC1 is associated with progression of colorectal traditional serrated adenomas.","date":"2024","source":"BMC gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/38429655","citation_count":3,"is_preprint":false},{"pmid":"39510490","id":"PMC_39510490","title":"Spatial and temporal expression analysis of BMP signal modifiers, Smoc1 and Smoc2, from postnatal to adult developmental stages in the mouse testis.","date":"2024","source":"Gene expression patterns : GEP","url":"https://pubmed.ncbi.nlm.nih.gov/39510490","citation_count":1,"is_preprint":false},{"pmid":"39119686","id":"PMC_39119686","title":"The SPARC-related modular calcium binding 1 ( Smoc1 ) regulated by androgen is required for mouse gubernaculum development and testicular descent.","date":"2024","source":"Asian journal of andrology","url":"https://pubmed.ncbi.nlm.nih.gov/39119686","citation_count":1,"is_preprint":false},{"pmid":"39291144","id":"PMC_39291144","title":"Identification of high-performing antibodies for SPARC-related modular calcium-binding protein 1 (SMOC-1) for use in Western Blot and immunoprecipitation.","date":"2024","source":"F1000Research","url":"https://pubmed.ncbi.nlm.nih.gov/39291144","citation_count":1,"is_preprint":false},{"pmid":"41714037","id":"PMC_41714037","title":"The Runx2-SMOC axis in skeletal development: Expanding roles of Smoc1 and Smoc2 in development and disease.","date":"2026","source":"Journal of oral biosciences","url":"https://pubmed.ncbi.nlm.nih.gov/41714037","citation_count":0,"is_preprint":false},{"pmid":"38059661","id":"PMC_38059661","title":"A novel SMOC1 pathogenic homozygous variant in a fetus with mesomelia of the lower limbs, micrognathia and hypertelorism and an incidental finding of CYP21A2-related congenital adrenal hyperplasia.","date":"2023","source":"Prenatal diagnosis","url":"https://pubmed.ncbi.nlm.nih.gov/38059661","citation_count":0,"is_preprint":false},{"pmid":"36711863","id":"PMC_36711863","title":"C. elegans SMOC-1 interacts with both BMP and glypican to regulate BMP signaling.","date":"2023","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/36711863","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":19154,"output_tokens":4617,"usd":0.063358,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":12862,"output_tokens":5028,"usd":0.095005,"stage2_stop_reason":"end_turn"},"total_usd":0.158363,"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\": 2002,\n      \"finding\": \"SMOC-1 is a secreted modular glycoprotein with a calcium-dependent conformation, containing an EF-hand calcium-binding domain homologous to BM-40, two thyroglobulin-like domains, a follistatin-like domain, and a novel domain. It localizes to basement membranes and other extracellular matrices, as demonstrated by immunofluorescence and immunogold electron microscopy in kidney, skeletal muscle, and zona pellucida.\",\n      \"method\": \"Recombinant expression in human cells, Northern blot, RT-PCR, immunoblot, immunofluorescence, immunogold electron microscopy\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (recombinant expression, structural characterization, direct localization by immunogold EM) in foundational characterization paper\",\n      \"pmids\": [\"12130637\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Xenopus SMOC-1 acts as a BMP antagonist downstream of the BMP receptor, distinct from extracellular ligand-binding antagonists like noggin. It antagonizes BMP activity even in the presence of a constitutively active BMP receptor, and the mechanism involves MAPK-mediated phosphorylation of the Smad linker region. Morpholino-based loss-of-function reveals SMOC-1 is essential for postgastrulation development.\",\n      \"method\": \"Gain-of-function assays in Xenopus embryos, constitutively active BMP receptor constructs, antisense morpholino knockdown, MAPK pathway analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal approaches (gain-of-function, constitutively active receptor epistasis, morpholino loss-of-function) in a single rigorous study establishing downstream receptor mechanism\",\n      \"pmids\": [\"19414592\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"SMOC1 is required for ocular and limb development. Smoc1 null mice exhibit aplasia/hypoplasia of optic nerves, hypoplastic fibula, bowed tibia, and syndactyly. Soft tissue syndactyly results from inhibited apoptosis linked to disturbed BMP signaling gene expression in interdigital mesenchyme.\",\n      \"method\": \"Smoc1 null mouse generation, histological and phenotypic analysis, expression analysis of BMP signaling genes in interdigital mesenchyme\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean knockout mouse with specific cellular phenotype (inhibited apoptosis) linked to BMP pathway gene expression changes, replicated across multiple families\",\n      \"pmids\": [\"21194678\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"SMOC1 knockdown significantly inhibited mineralization and expression of osteoblast differentiation markers in bone marrow-derived mesenchymal stem cells, while SMOC1 overexpression increased osteoblast differentiation-related gene expression, identifying SMOC1 as a regulator of osteoblast differentiation.\",\n      \"method\": \"shRNA knockdown, cDNA overexpression, osteoblast differentiation assays (mineralization, marker gene expression) in BMSCs\",\n      \"journal\": \"Journal of proteome research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — bidirectional perturbation (KD and OE) with defined cellular phenotype, single lab\",\n      \"pmids\": [\"20359165\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"SMOC-1 directly interacts with tenascin-C, as confirmed by co-immunoprecipitation and Surface Plasmon Resonance Spectroscopy (KD = 2.59×10⁻⁹ M). This binding is reduced in the presence of EDTA, indicating calcium dependence. SMOC1 can counteract the chemo-attractive effect of tenascin-C on glioma cells.\",\n      \"method\": \"Tenascin-C affinity column purification, mass spectrometry, co-immunoprecipitation, Surface Plasmon Resonance Spectroscopy, cell migration assay\",\n      \"journal\": \"Matrix biology : journal of the International Society for Matrix Biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — quantitative binding kinetics by SPR plus co-IP confirmation plus functional cell migration assay, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"21349332\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"SMOC-1 functions as a BMP antagonist during mammalian limb and eye development. Loss of SMOC-1 (gene-trap reducing mRNA to ~10% of wild-type) causes hindlimb post-axial oligosyndactyly, coloboma, and cleft palate, phenocopying human ophthalmo-acromelic syndrome. Missense mutations are located in the second Thyroglobulin Type-1 domain.\",\n      \"method\": \"Gene-trap mouse mutant (Smoc1tm1a), phenotypic analysis, mutation mapping to protein domains\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — hypomorphic gene-trap allele with dose-dependent penetrant phenotype, multiple families with mutations in specific protein domain, independent replication of BMP antagonist role\",\n      \"pmids\": [\"21750680\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"SMOC-1 binds heparin and heparan sulfate (but not chondroitin sulfate or dermatan sulfate) via a basic region in the EC domain consisting of two antiparallel alpha helices. Heparin-binding residues in both helices must be replaced to abolish binding. The heparin-binding activity of the EC domain mediates adhesion of epithelial HaCaT cells to SMOC-1; heparin-binding-impaired mutants failed to support cell adhesion.\",\n      \"method\": \"Size-exclusion chromatography, intrinsic tryptophan fluorescence measurements, site-directed mutagenesis of heparin-binding residues, cell adhesion assay\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — quantitative binding assays plus mutagenesis plus functional cell adhesion readout, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"23437253\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"SMOC1 associates with endoglin (an endothelium-specific auxiliary TGF-β receptor) and acts as a negative regulator of ALK5/SMAD2 signaling, thereby promoting TGF-β signaling via ALK1 and endothelial cell activation. SMOC1 downregulation effects on SMAD2 phosphorylation were abolished by endoglin knockdown. SMOC1 expression is regulated by hypoxia via miR-223 downregulation.\",\n      \"method\": \"siRNA silencing, co-immunoprecipitation, proximity ligation assay, immunohistochemistry, in vitro angiogenesis assays, aortic ring sprouting, postnatal retinal angiogenesis in SMOC1+/- mice\",\n      \"journal\": \"Cardiovascular research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP plus proximity ligation assay plus epistasis (endoglin KD rescuing SMOC1 KD effect) plus in vivo validation in heterozygous mice\",\n      \"pmids\": [\"25750188\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"C. elegans SMOC-1 acts cell-nonautonomously as a positive modulator of BMP signaling. It antagonizes the glypican LON-2 and acts through the BMP ligand DBL-1. Double-mutant analysis placed SMOC-1 upstream of DBL-1/BMP. Human SMOC1 and SMOC2 each partially rescue the smoc-1(0) mutant phenotype, demonstrating evolutionary conservation of the BMP-modulatory function.\",\n      \"method\": \"smoc-1 loss-of-function mutant analysis, smoc-1 overexpression with BMP reporter, double-mutant epistasis analysis, cell-specific rescue experiments, human SMOC1/SMOC2 cross-species rescue\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with double mutants, cell-nonautonomy established by tissue-specific rescue, cross-species rescue with human protein confirms conservation\",\n      \"pmids\": [\"30518528\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"SMOC1 silencing suppresses angiotensin II-induced myocardial fibroblast fibrosis by affecting the BMP2/Smad signaling pathway, reducing ROS content, oxidative stress, and fibrosis-associated protein expression.\",\n      \"method\": \"siRNA knockdown, Cell Counting Kit-8 viability assay, flow cytometry (ROS), ELISA, Western blot, RT-qPCR in myocardial fibroblasts\",\n      \"journal\": \"Oncology letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — KD with defined phenotype and pathway (BMP2/Smad), single lab, multiple readouts but no direct binding or reconstitution\",\n      \"pmids\": [\"30127878\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"SMOC1 is a glucose-responsive hepatokine that improves glycemic control by inhibiting cAMP-PKA-CREB signaling in the liver, leading to decreased gluconeogenic gene expression and suppression of hepatic glucose output. Acute IP administration improved insulin sensitivity without changing insulin secretion; liver-specific overexpression and stabilized SMOC1-Fc fusion protein induced durable improvements in db/db mice.\",\n      \"method\": \"Acute IP administration in mice, liver-specific overexpression, SMOC1-Fc fusion protein weekly injections in db/db mice, cAMP-PKA-CREB pathway analysis, gluconeogenic gene expression assays, glucose tolerance/insulin sensitivity tests\",\n      \"journal\": \"Science translational medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple in vivo models (acute dosing, liver OE, fusion protein), mechanistic pathway (cAMP-PKA-CREB) identified, multiple orthogonal readouts in a single rigorous study\",\n      \"pmids\": [\"32878981\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Fasting-induced upregulation of SMOC1 in endothelial cells promotes angiogenesis. Downregulation of SMOC1 attenuated fasting/refeeding-induced pro-angiogenic effects (proliferation, migration, tube formation), establishing SMOC1 as a mediator of fasting-induced angiogenesis.\",\n      \"method\": \"Transcriptome sequencing, siRNA knockdown, in vitro angiogenesis assays (proliferation, migration, tube formation), immunofluorescent staining in wound models\",\n      \"journal\": \"Theranostics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — KD with specific angiogenic phenotype confirmed by multiple in vitro assays and in vivo staining, single lab\",\n      \"pmids\": [\"32206122\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Smoc1 and Smoc2 are direct transcriptional targets of Runx2 and are required for bone formation. Smoc1 KO mice display absent fibula formation; Smoc1/Smoc2 double KO mice show absent skull, shortened tibiae, absent fibulae, and impaired endochondral bone formation. Smoc1 or Smoc2 knockdown inhibits osteoblastogenesis in vitro.\",\n      \"method\": \"RNA sequencing to identify Runx2 targets, Smoc1 KO mice, Smoc1/Smoc2 double KO mice, in vitro knockdown and osteoblastogenesis assays\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — RNA-seq target identification plus single and double KO mouse models with specific skeletal phenotypes, plus in vitro KD confirming cell-autonomous role\",\n      \"pmids\": [\"34667264\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"IL-4 and IL-13 inhibit SMOC1 expression in primary human keratinocytes. SMOC1 siRNA knockdown inhibited epidermal differentiation markers and increased the amplitude of Ca2+ peak response, demonstrating that SMOC1 modulates Ca2+-induced keratinocyte differentiation signals.\",\n      \"method\": \"siRNA knockdown of SMOC1, real-time Ca2+ influx measurement by flow cytometry and microscopy, expression analysis of differentiation markers\",\n      \"journal\": \"The Journal of investigative dermatology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — KD with specific Ca2+ transport and differentiation phenotype, single lab, two orthogonal readouts\",\n      \"pmids\": [\"33484701\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"C. elegans SMOC-1 directly binds both LON-2/glypican (via the EC domain) and the mature domain of DBL-1/BMP (requiring full-length SMOC-1), and can simultaneously bind both. SMOC-1 functions negatively in a LON-2/glypican-dependent manner and positively in a DBL-1/BMP-dependent manner to regulate BMP signaling. Drosophila and vertebrate SMOC proteins can also bind mature BMP dimers in silico.\",\n      \"method\": \"Biochemical binding assays (Co-IP, pulldown), structural modeling, molecular genetics (domain-specific mutants, double mutants), in vivo BMP reporter assays\",\n      \"journal\": \"PLoS biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — direct biochemical binding assays plus in vivo genetic epistasis plus domain-specific mutants establishing dual mechanism, replicated from preprint with additional data\",\n      \"pmids\": [\"37590248\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"SMOC1 is regulated by androgen (testosterone via the androgen receptor) in gubernacular cells, and SMOC1 in turn promotes gubernacular cell proliferation and expression of myogenic regulatory factors Pax7 and Myf5. siRNA knockdown of Smoc1 abolished testosterone-induced Pax7 and Myf5 upregulation, and exogenous SMOC1 rescued this effect, placing SMOC1 downstream of androgen signaling in gubernaculum development.\",\n      \"method\": \"Gene expression analysis in Lhcgr KO mice, testosterone administration with/without flutamide (androgen receptor antagonist), siRNA knockdown, in vitro gubernacular cell proliferation and myogenic differentiation assays\",\n      \"journal\": \"Asian journal of andrology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic model plus pharmacological epistasis plus KD/rescue in vitro, single lab\",\n      \"pmids\": [\"39119686\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SMOC1 expression in β-cells is increased in type 2 diabetes and drives β-cell dedifferentiation. Enhanced SMOC1 expression in β-cells decreased insulin expression and secretion and increased β-cell dedifferentiation markers.\",\n      \"method\": \"Single-cell and single-nucleus RNA-seq, RNA velocity, PAGA/cell trajectory inference, SMOC1 overexpression in β-cells with insulin secretion and dedifferentiation marker assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — trajectory inference plus functional overexpression assay with defined phenotype (decreased insulin secretion, increased dedifferentiation markers), single lab\",\n      \"pmids\": [\"41057332\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SMOC1 is a secreted modular calcium-binding matricellular glycoprotein that localizes to basement membranes and extracellular matrices, where it modulates BMP signaling (acting downstream of the BMP receptor via MAPK-Smad linker phosphorylation, and by simultaneously binding BMP ligands and glypican co-receptors), interacts with tenascin-C and endoglin to regulate TGF-β/ALK5 signaling, binds heparin/heparan sulfate through its EC domain to mediate cell adhesion, functions as a glucose-responsive hepatokine suppressing cAMP-PKA-CREB-driven gluconeogenesis, acts downstream of Runx2 to promote osteoblast differentiation and skeletal morphogenesis, is regulated by androgen to support gubernaculum development, and when aberrantly expressed in β-cells drives dedifferentiation and impairs insulin secretion.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SMOC1 is a secreted, calcium-binding matricellular glycoprotein that deposits in basement membranes and extracellular matrices and acts as a modulator of BMP and TGF-\\u03b2 signaling during development and tissue homeostasis [#0, #1]. Its multidomain architecture\\u2014an EF-hand calcium-binding region, thyroglobulin-like domains, a follistatin-like domain, and an extracellular calcium-binding (EC) domain\\u2014supports a calcium-dependent conformation and matrix localization [#0]. SMOC1 modulates BMP signaling through dual mechanisms: it acts downstream of the BMP receptor via MAPK-dependent phosphorylation of the Smad linker region [#1], and it directly binds both mature BMP ligand dimers and the glypican co-receptor, enabling it to function negatively in a glypican-dependent manner and positively in a BMP-ligand-dependent manner [#14]. Through these activities SMOC1 is essential for ocular, limb, and skeletal development, with loss causing optic and skeletal malformations that phenocopy ophthalmo-acromelic syndrome [#2, #5]. SMOC1 is a direct transcriptional target of Runx2 and drives osteoblast differentiation and endochondral bone formation [#3, #12]. The EC domain binds heparin and heparan sulfate through a basic helical region to mediate cell adhesion [#6], and SMOC1 binds tenascin-C and associates with endoglin to negatively regulate ALK5/SMAD2 signaling in endothelial cells [#4, #7]. Beyond development, SMOC1 functions as a glucose-responsive hepatokine that suppresses cAMP-PKA-CREB-driven gluconeogenesis to improve glycemic control [#10], whereas its aberrant expression in \\u03b2-cells drives dedifferentiation and impairs insulin secretion [#16].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Established SMOC1 as a secreted, calcium-dependent modular matricellular glycoprotein and defined its domain architecture and matrix localization, providing the structural foundation for all later functional work.\",\n      \"evidence\": \"Recombinant expression, structural characterization, and immunogold EM localization in kidney, muscle, and zona pellucida\",\n      \"pmids\": [\"12130637\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No binding partners or signaling function identified at this stage\", \"Function of individual domains not yet assigned\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Defined SMOC1 as a BMP antagonist acting downstream of the BMP receptor rather than by sequestering ligand, distinguishing it mechanistically from classical extracellular antagonists.\",\n      \"evidence\": \"Gain-of-function and constitutively active receptor epistasis plus morpholino knockdown in Xenopus, with MAPK-Smad linker analysis\",\n      \"pmids\": [\"19414592\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct molecular target of SMOC1 in the receptor-downstream cascade not identified\", \"Whether the mechanism is conserved in mammals untested here\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Linked SMOC1 loss to specific ocular and limb developmental defects in mammals and connected the syndactyly phenotype to disrupted BMP-dependent interdigital apoptosis.\",\n      \"evidence\": \"Smoc1 null mouse phenotyping with BMP signaling gene expression analysis in interdigital mesenchyme\",\n      \"pmids\": [\"21194678\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular intermediary between SMOC1 and apoptotic BMP genes not defined\", \"Tissue-autonomy of the requirement not resolved\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Identified SMOC1 as a bidirectional regulator of osteoblast differentiation, extending its role to skeletal cell fate.\",\n      \"evidence\": \"shRNA knockdown and overexpression with mineralization and marker assays in BMSCs\",\n      \"pmids\": [\"20359165\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab, no in vivo skeletal validation at this stage\", \"Mechanistic link to a defined pathway not established\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Identified the first direct binding partner, tenascin-C, in a calcium-dependent interaction with functional consequences for cell migration.\",\n      \"evidence\": \"Affinity purification, mass spectrometry, Co-IP, SPR kinetics, and glioma migration assay\",\n      \"pmids\": [\"21349332\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Binding domain on SMOC1 not mapped\", \"Physiological context of the SMOC1-tenascin-C axis unresolved\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Confirmed in mammals that SMOC1 is a BMP antagonist essential for limb and eye development and tied human ophthalmo-acromelic syndrome mutations to a specific thyroglobulin domain.\",\n      \"evidence\": \"Hypomorphic gene-trap mouse with dose-dependent phenotype and human mutation mapping\",\n      \"pmids\": [\"21750680\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of the thyroglobulin domain mutations on protein activity not biochemically tested\", \"Mechanism of antagonism not resolved here\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Mapped a heparin/heparan-sulfate-binding activity to a basic helical region of the EC domain and showed this activity mediates cell adhesion.\",\n      \"evidence\": \"Size-exclusion chromatography, tryptophan fluorescence, site-directed mutagenesis, and HaCaT cell adhesion assay\",\n      \"pmids\": [\"23437253\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cell-surface heparan sulfate proteoglycan partner not identified\", \"Relationship between adhesion activity and BMP modulation unclear\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Extended SMOC1 function to TGF-\\u03b2 signaling by showing it associates with endoglin and negatively regulates ALK5/SMAD2, promoting ALK1-driven endothelial activation.\",\n      \"evidence\": \"siRNA, reciprocal Co-IP, proximity ligation assay, endoglin-knockdown epistasis, and angiogenesis assays in SMOC1+/- mice\",\n      \"pmids\": [\"25750188\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the SMOC1-endoglin interaction not defined\", \"How SMOC1 discriminates between ALK1 and ALK5 not resolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Demonstrated evolutionary conservation and cell-nonautonomy of SMOC1's BMP-modulatory role and placed it genetically relative to glypican and BMP ligand.\",\n      \"evidence\": \"C. elegans loss-of-function, double-mutant epistasis, tissue-specific rescue, and human SMOC1/SMOC2 cross-species rescue\",\n      \"pmids\": [\"30518528\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct binding interactions not yet demonstrated at this stage\", \"Whether positive and negative effects use the same molecular interaction unknown\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Connected SMOC1 to pathological fibrosis via the BMP2/Smad pathway and oxidative stress in cardiac fibroblasts.\",\n      \"evidence\": \"siRNA knockdown with ROS, ELISA, Western blot, and qPCR readouts in myocardial fibroblasts\",\n      \"pmids\": [\"30127878\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct binding or reconstitution\", \"Single-lab, in vitro only\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Revealed an unexpected metabolic role: SMOC1 acts as a glucose-responsive hepatokine that suppresses gluconeogenesis through cAMP-PKA-CREB inhibition.\",\n      \"evidence\": \"Acute IP dosing, liver-specific overexpression, and SMOC1-Fc fusion therapy in db/db mice with pathway and glucose-handling assays\",\n      \"pmids\": [\"32878981\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Receptor or surface target mediating the hepatokine effect not identified\", \"Mechanistic link between matrix/BMP roles and metabolic signaling unresolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Implicated SMOC1 as a mediator of fasting-induced angiogenesis in endothelial cells.\",\n      \"evidence\": \"Transcriptome sequencing, siRNA knockdown, and in vitro/in vivo angiogenesis assays\",\n      \"pmids\": [\"32206122\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Signaling pathway downstream of SMOC1 in this context not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Placed SMOC1 in a defined transcriptional hierarchy as a direct Runx2 target required for bone formation, with redundancy with SMOC2.\",\n      \"evidence\": \"RNA-seq target identification, single and Smoc1/Smoc2 double KO mice, and in vitro osteoblastogenesis knockdown\",\n      \"pmids\": [\"34667264\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular effector by which SMOC1 promotes osteoblastogenesis not defined\", \"Extent of functional overlap versus distinct roles of SMOC1 and SMOC2 unresolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Showed SMOC1 modulates calcium-induced keratinocyte differentiation and is suppressed by type 2 inflammatory cytokines.\",\n      \"evidence\": \"siRNA knockdown, real-time Ca2+ imaging, and differentiation marker analysis in primary keratinocytes\",\n      \"pmids\": [\"33484701\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking SMOC1 to Ca2+ flux not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Resolved the dual-mode mechanism by demonstrating that SMOC1 directly binds both glypican (via the EC domain) and mature BMP ligand simultaneously, explaining its opposing negative and positive effects on BMP signaling.\",\n      \"evidence\": \"Co-IP, pulldown, domain-specific mutants, structural modeling, and in vivo BMP reporter assays in C. elegans\",\n      \"pmids\": [\"37590248\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and structure of the SMOC1-BMP-glypican complex not solved\", \"Whether mammalian SMOC1 uses the identical dual mechanism in vivo not directly tested\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Positioned SMOC1 downstream of androgen receptor signaling in gubernaculum development, driving myogenic gene expression and cell proliferation.\",\n      \"evidence\": \"Lhcgr KO mice, testosterone/flutamide pharmacological epistasis, and siRNA knockdown/rescue in gubernacular cells\",\n      \"pmids\": [\"39119686\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular mechanism by which SMOC1 induces Pax7/Myf5 not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified pathological SMOC1 upregulation in \\u03b2-cells as a driver of dedifferentiation and impaired insulin secretion in type 2 diabetes.\",\n      \"evidence\": \"Single-cell/single-nucleus RNA-seq, trajectory inference, and SMOC1 overexpression with insulin secretion and dedifferentiation marker assays\",\n      \"pmids\": [\"41057332\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Signaling pathway mediating \\u03b2-cell dedifferentiation by SMOC1 not defined\", \"Causal role in vivo not established\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Whether the single-protein activities\\u2014BMP/glypican binding, heparin-mediated adhesion, endoglin/TGF-\\u03b2 regulation, and hepatokine signaling\\u2014are unified by a common biochemical mechanism, and what cell-surface receptor transduces the metabolic effect, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No receptor identified for the hepatokine/metabolic function\", \"No structure of any SMOC1-partner complex\", \"Integration of developmental and metabolic roles unexplained\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [1, 7, 14]},\n      {\"term_id\": \"GO:0005509\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0008201\", \"supporting_discovery_ids\": [6]},\n      {\"term_id\": \"GO:0098631\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [0, 10]},\n      {\"term_id\": \"GO:0031012\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 7, 14]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [2, 5, 12]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [10]},\n      {\"term_id\": \"R-HSA-1474244\", \"supporting_discovery_ids\": [0, 6]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"TNC\", \"ENG\", \"DBL-1/BMP\", \"LON-2/glypican\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}