{"gene":"CSRP3","run_date":"2026-06-09T22:57:19","timeline":{"discoveries":[{"year":2008,"finding":"MLP (encoded by CSRP3) is mainly a cytosolic component of cardiomyocytes and not tightly anchored to sarcomeric structures, as demonstrated using a newly designed monoclonal antibody. At least one HCM-associated mutant form of MLP appears destabilized in the heart of HCM patients, based on in vitro and in vivo functional analyses.","method":"Monoclonal antibody immunolocalization, in vitro and in vivo functional analyses of mutant protein stability","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct antibody-based localization combined with in vitro and in vivo protein stability assays, single lab but two orthogonal approaches","pmids":["18505755"],"is_preprint":false},{"year":2015,"finding":"MLP/CSRP3 interacts with LC3 (as shown by co-immunoprecipitation and proximity ligation assay) and is required for correct autophagosome formation and autophagic flux in C2C12 mouse myoblasts. MLP silencing decreases LC3-II staining, impairs degradation of long-lived proteins, impairs myoblast differentiation (reduced MyoD1, MyoG1, myosin heavy chain expression), and increases susceptibility to apoptosis (increased caspase-3 and PARP cleavage).","method":"Co-immunoprecipitation, proximity ligation assay (PLA), siRNA silencing and overexpression in C2C12 cells, LC3-II immunostaining, long-lived protein degradation assay, ultrastructural analysis, caspase/PARP cleavage assay","journal":"Cell death discovery","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP plus PLA plus multiple functional readouts, single lab","pmids":["27551448"],"is_preprint":false},{"year":2019,"finding":"Knockdown of CSRP3 in chicken satellite cells inhibits their differentiation into myotubes without affecting proliferation. The mechanism involves upregulation of TGF-β and Smad3 mRNA and protein, and increased phosphorylation of Smad3 during differentiation.","method":"siRNA knockdown in primary chicken satellite cells, qPCR and western blot for TGF-β/Smad3 pathway components, differentiation assay (myotube formation at 24/48/72 h)","journal":"Gene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA loss-of-function with defined cellular phenotype and pathway placement via Smad3 phosphorylation, single lab, two orthogonal methods (qPCR + western)","pmids":["30930226"],"is_preprint":false},{"year":2020,"finding":"CSRP3 interacts with LC3 protein to promote autophagosome formation during autophagy in chicken primary myoblasts. CSRP3 silencing impairs autophagy (reduced ATG5, ATG7 mRNA, and LC3-II and Beclin-1 protein levels), increases apoptosis (elevated caspase-3 and caspase-9 cleavage), and these effects are alleviated by autophagy activation.","method":"siRNA knockdown in chicken primary myoblasts, co-immunoprecipitation (CSRP3–LC3 interaction), western blot and qPCR for autophagy markers, caspase cleavage assay, autophagy activator rescue experiment","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus multiple functional readouts plus rescue experiment, single lab; replicates finding from PMID:27551448","pmids":["31979369"],"is_preprint":false},{"year":2022,"finding":"CSRP3 promotes myoblast differentiation by undergoing nuclear translocation in response to vitamin C, after which it interacts with the myogenic transcription factors MyoD and MyoG to promote muscle development and muscle injury repair in mice.","method":"Cell and molecular biology, proteomics, nuclear fractionation/localization imaging, co-immunoprecipitation of CSRP3 with MyoD and MyoG, C2C12 differentiation assay, mouse muscle injury model","journal":"Journal of agricultural and food chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus localization plus in vivo injury model, single lab, multiple orthogonal methods","pmids":["35652451"],"is_preprint":false},{"year":2019,"finding":"CSRP3 is a target of the polyphenol metabolite 4-methylcatechol sulfate in cardiomyocytes. siRNA silencing of CSRP3 reverses phenylephrine-induced cardiomyocyte hypertrophy, and CSRP3 overexpression induces hypertrophy, establishing CSRP3 as a mediator of cardiomyocyte hypertrophic responses.","method":"siRNA silencing and overexpression in neonatal rat ventricular cardiomyocytes, phenylephrine-induced hypertrophy model, proteomics identification, 4-methylcatechol sulfate treatment","journal":"The Journal of nutritional biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss- and gain-of-function in primary cardiomyocytes with defined phenotypic readout, single lab, two orthogonal approaches (KD + OE)","pmids":["30703746"],"is_preprint":false},{"year":2022,"finding":"Computational virtual mutagenesis and molecular dynamics simulations show that the HCM/DCM-associated L44P mutation in the LIM domain of CSRP3 destabilizes the domain by altering secondary structure and disrupting a hydrophobic interaction with Phenylalanine 35, whereas the neutral L44M substitution does not have this effect.","method":"In silico mutational landscape mapping, molecular dynamics (MD) simulations, sequence and structural analysis of LIM domains","journal":"Scientific reports","confidence":"Low","confidence_rationale":"Tier 4 / Weak — purely computational, no experimental validation of predicted structural effects","pmids":["35241752"],"is_preprint":false},{"year":2026,"finding":"CSRP3 binds to D-lactate dehydrogenase (LDHD) via a specific 33-amino acid region, promoting D-lactate metabolism in skeletal muscle. This interaction regulates mitochondrial morphology, biogenesis, oxidative phosphorylation efficiency, and TCA cycle activity, driving skeletal muscle mitochondrial metabolic rewiring and fiber type remodeling toward oxidative (aerobic) myofibers. AAV-mediated CSRP3 knockdown perturbs mitochondrial energy metabolism, reduces oxidative fiber proportion, and compromises exercise performance.","method":"Co-immunoprecipitation (CSRP3–LDHD), domain mapping (33-aa region), AAV-mediated knockdown in live mice, mitochondrial function assays, myofiber type analysis, exercise performance testing","journal":"Metabolism: clinical and experimental","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP with domain mapping plus in vivo AAV knockdown with multiple metabolic readouts, single lab","pmids":["41812695"],"is_preprint":false},{"year":2012,"finding":"Csrp3 mRNA and protein levels decline in rat skeletal muscle following removal of voluntary running (wheel-lock model), identifying CSRP3 as a mechano-sensitive gene whose expression is regulated by mechanical loading in skeletal muscle.","method":"Affymetrix microarray of polyribosomal fraction, RT-PCR verification, whole-tissue mRNA and protein quantification across multiple time points after wheel-lock","journal":"Journal of applied physiology","confidence":"Low","confidence_rationale":"Tier 3 / Moderate — expression-level readout with RT-PCR and protein validation, but no direct mechanistic intervention; establishes mechano-sensitivity but not molecular mechanism","pmids":["22282489"],"is_preprint":false}],"current_model":"CSRP3/MLP is a cytosolic, muscle-specific LIM-domain protein that functions as a mechanosensor and structural regulator in cardiac and skeletal muscle: it promotes autophagosome formation by directly binding LC3, drives myogenic differentiation by translocating to the nucleus and interacting with MyoD and MyoG, suppresses cardiomyocyte hypertrophy, modulates TGF-β/Smad3 signaling to support satellite cell differentiation, and enhances skeletal muscle aerobic metabolism by binding LDHD to promote D-lactate metabolism and mitochondrial biogenesis; disease-causing missense mutations destabilize its LIM domains, and loss of CSRP3 causes dilated or hypertrophic cardiomyopathy."},"narrative":{"mechanistic_narrative":"CSRP3 (MLP) is a muscle-specific LIM-domain protein that acts as a structural and regulatory hub in cardiac and skeletal muscle, coordinating autophagy, myogenic differentiation, metabolic remodeling, and hypertrophic responses [PMID:27551448, PMID:35652451, PMID:41812695]. In cardiomyocytes it is predominantly cytosolic rather than tightly anchored to sarcomeric structures, and at least one HCM-associated mutant form is destabilized in patient hearts [PMID:18505755]. CSRP3 directly binds LC3 to promote autophagosome formation and sustain autophagic flux; its loss impairs autophagy, blocks myoblast differentiation, and sensitizes cells to apoptosis [PMID:27551448, PMID:31979369]. During differentiation CSRP3 translocates to the nucleus and engages the myogenic transcription factors MyoD and MyoG to drive muscle development and injury repair [PMID:35652451], and it supports satellite cell differentiation by restraining TGF-β/Smad3 signaling [PMID:30930226]. In skeletal muscle CSRP3 binds D-lactate dehydrogenase (LDHD) through a defined 33-amino-acid region to promote D-lactate metabolism, mitochondrial biogenesis, oxidative phosphorylation, and a shift toward oxidative myofibers, with in vivo knockdown compromising exercise performance [PMID:41812695]. In the heart CSRP3 mediates hypertrophic responses, as silencing reverses and overexpression induces cardiomyocyte hypertrophy [PMID:30703746]. Its expression is mechanically regulated, declining when mechanical loading is withdrawn [PMID:22282489].","teleology":[{"year":2008,"claim":"Established that MLP is mainly cytosolic in cardiomyocytes rather than a rigidly sarcomere-anchored protein, and linked disease mutations to protein destabilization, reframing how its function and pathogenicity should be interpreted.","evidence":"Monoclonal antibody immunolocalization plus in vitro and in vivo mutant stability assays in cardiomyocytes","pmids":["18505755"],"confidence":"Medium","gaps":["Does not define the cytosolic binding partners that retain MLP","Mechanistic basis of mutant destabilization not resolved at structural level"]},{"year":2012,"claim":"Identified CSRP3 as a mechano-sensitive gene by showing its expression tracks mechanical loading, connecting it to load-dependent muscle adaptation.","evidence":"Microarray of polyribosomal fraction with RT-PCR and protein validation in rat wheel-lock model","pmids":["22282489"],"confidence":"Low","gaps":["Expression correlation only, no molecular mechanism of mechanotransduction","Does not show CSRP3 is causal in the adaptive response"]},{"year":2015,"claim":"Defined a direct CSRP3–LC3 interaction required for autophagosome formation and linked autophagy competence to myoblast differentiation and survival, placing CSRP3 in the autophagy machinery.","evidence":"Reciprocal co-IP, PLA, siRNA/overexpression with LC3-II, protein degradation, differentiation, and caspase/PARP readouts in C2C12 cells","pmids":["27551448"],"confidence":"Medium","gaps":["LC3 binding interface on CSRP3 not mapped","Whether autophagy defect is the proximate cause of impaired differentiation not separated from other roles"]},{"year":2019,"claim":"Showed CSRP3 supports satellite cell differentiation by restraining the TGF-β/Smad3 axis, providing a signaling mechanism for its pro-differentiation effect.","evidence":"siRNA knockdown in primary chicken satellite cells with qPCR/western for TGF-β/Smad3 and myotube formation assay","pmids":["30930226"],"confidence":"Medium","gaps":["No demonstrated direct interaction linking CSRP3 to TGF-β/Smad3 components","Whether Smad3 modulation is direct or downstream of autophagy/transcriptional roles unknown"]},{"year":2019,"claim":"Demonstrated CSRP3 is a causal mediator of cardiomyocyte hypertrophy, with loss reversing and gain inducing the hypertrophic phenotype.","evidence":"siRNA silencing and overexpression in neonatal rat ventricular cardiomyocytes under phenylephrine-induced hypertrophy","pmids":["30703746"],"confidence":"Medium","gaps":["Downstream effectors of CSRP3-driven hypertrophy not identified","Relationship to its autophagy and metabolic roles not integrated"]},{"year":2020,"claim":"Replicated the CSRP3–LC3 autophagy mechanism in an independent species and showed autophagy activation rescues the apoptotic phenotype, strengthening the autophagy-promoting role.","evidence":"Co-IP, siRNA knockdown, autophagy/apoptosis markers, and autophagy activator rescue in chicken primary myoblasts","pmids":["31979369"],"confidence":"Medium","gaps":["Binding region still unmapped","Does not address the cardiac context"]},{"year":2022,"claim":"Revealed a nuclear, transcriptional arm of CSRP3 function: stimulus-induced nuclear translocation and interaction with MyoD and MyoG to drive myogenesis and injury repair.","evidence":"Nuclear fractionation/imaging, co-IP with MyoD and MyoG, C2C12 differentiation, and mouse muscle injury model","pmids":["35652451"],"confidence":"Medium","gaps":["Mechanism triggering nuclear translocation beyond vitamin C stimulus unclear","Whether CSRP3 directly modulates MyoD/MyoG target transcription not shown"]},{"year":2022,"claim":"Provided a structural rationale for pathogenicity by showing the HCM/DCM L44P mutation destabilizes the LIM domain via disrupted hydrophobic packing, while a neutral substitution does not.","evidence":"In silico virtual mutagenesis and molecular dynamics simulations of the LIM domain","pmids":["35241752"],"confidence":"Low","gaps":["Purely computational with no experimental validation of predicted destabilization","Does not connect destabilization to a specific functional loss"]},{"year":2026,"claim":"Connected CSRP3 to skeletal muscle energy metabolism by mapping a 33-aa LDHD-binding region that drives D-lactate metabolism, mitochondrial biogenesis, oxidative fiber remodeling, and exercise capacity.","evidence":"Co-IP with domain mapping, AAV-mediated knockdown in mice, mitochondrial function and myofiber-type assays, exercise testing","pmids":["41812695"],"confidence":"Medium","gaps":["How LDHD binding mechanistically alters mitochondrial biogenesis is not resolved","Integration with autophagic and transcriptional roles unknown"]},{"year":null,"claim":"How CSRP3 coordinates its distinct cytosolic (autophagy, metabolism), nuclear (myogenic transcription), and hypertrophy-modulating activities into a unified mechanosensing program remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structure of CSRP3 bound to LC3, LDHD, or MyoD/MyoG","Signals partitioning CSRP3 between cytosol and nucleus not defined","Causal link between LIM-domain destabilization and specific functional losses not experimentally established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[1,3,7]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[4]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[4]}],"pathway":[{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[1,3]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[2,4]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[7]}],"complexes":[],"partners":["LC3","MYOD","MYOG","LDHD"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P50461","full_name":"Cysteine and glycine-rich protein 3","aliases":["Cardiac LIM protein","Cysteine-rich protein 3","CRP3","LIM domain protein, cardiac","Muscle LIM protein"],"length_aa":194,"mass_kda":21.0,"function":"Positive regulator of myogenesis. Acts as a cofactor for myogenic bHLH transcription factors such as MYOD1, and probably MYOG and MYF6. Enhances the DNA-binding activity of the MYOD1:TCF3 isoform E47 complex and may promote formation of a functional MYOD1:TCF3 isoform E47:MEF2A complex involved in myogenesis (By similarity). Plays a crucial and specific role in the organization of cytosolic structures in cardiomyocytes. Could play a role in mechanical stretch sensing. May be a scaffold protein that promotes the assembly of interacting proteins at Z-line structures. It is essential for calcineurin anchorage to the Z line. Required for stress-induced calcineurin-NFAT activation (By similarity). The role in regulation of cytoskeleton dynamics by association with CFL2 is reported conflictingly: Shown to enhance CFL2-mediated F-actin depolymerization dependent on the CSRP3:CFL2 molecular ratio, and also shown to reduce the ability of CLF1 and CFL2 to enhance actin depolymerization (PubMed:19752190, PubMed:24934443). Proposed to contribute to the maintenance of muscle cell integrity through an actin-based mechanism. Can directly bind to actin filaments, cross-link actin filaments into bundles without polarity selectivity and protect them from dilution- and cofilin-mediated depolymerization; the function seems to involve its self-association (PubMed:24934443). In vitro can inhibit PKC/PRKCA activity (PubMed:27353086). Proposed to be involved in cardiac stress signaling by down-regulating excessive PKC/PRKCA signaling (By similarity) May play a role in early sarcomere organization. Overexpression in myotubes negatively regulates myotube differentiation. By association with isoform 1 and thus changing the CSRP3 isoform 1:CFL2 stoichiometry is proposed to down-regulate CFL2-mediated F-actin depolymerization","subcellular_location":"Cytoplasm, myofibril, sarcomere, Z line","url":"https://www.uniprot.org/uniprotkb/P50461/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CSRP3","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/CSRP3","total_profiled":1310},"omim":[{"mim_id":"617195","title":"MUSCULOSKELETAL EMBRYONIC NUCLEAR PROTEIN 1; MUSTN1","url":"https://www.omim.org/entry/617195"},{"mim_id":"615396","title":"LEFT VENTRICULAR NONCOMPACTION 10; LVNC10","url":"https://www.omim.org/entry/615396"},{"mim_id":"612754","title":"GLUTAREDOXIN 3; GLRX3","url":"https://www.omim.org/entry/612754"},{"mim_id":"612124","title":"CARDIOMYOPATHY, FAMILIAL HYPERTROPHIC, 12; CMH12","url":"https://www.omim.org/entry/612124"},{"mim_id":"609470","title":"LEFT VENTRICULAR NONCOMPACTION 2; LVNC2","url":"https://www.omim.org/entry/609470"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Uncertain","locations":[{"location":"Cytosol","reliability":"Uncertain"},{"location":"Nucleoplasm","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"heart muscle","ntpm":2447.5},{"tissue":"skeletal muscle","ntpm":1545.8},{"tissue":"tongue","ntpm":540.3}],"url":"https://www.proteinatlas.org/search/CSRP3"},"hgnc":{"alias_symbol":["CLP","MLP","CMD1M"],"prev_symbol":[]},"alphafold":{"accession":"P50461","domains":[{"cath_id":"2.10.110.10","chopping":"8-85","consensus_level":"medium","plddt":82.154,"start":8,"end":85},{"cath_id":"2.10.110.10","chopping":"131-175","consensus_level":"high","plddt":86.8909,"start":131,"end":175}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P50461","model_url":"https://alphafold.ebi.ac.uk/files/AF-P50461-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P50461-F1-predicted_aligned_error_v6.png","plddt_mean":73.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CSRP3","jax_strain_url":"https://www.jax.org/strain/search?query=CSRP3"},"sequence":{"accession":"P50461","fasta_url":"https://rest.uniprot.org/uniprotkb/P50461.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P50461/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P50461"}},"corpus_meta":[{"pmid":"19412328","id":"PMC_19412328","title":"Coding sequence mutations identified in MYH7, TNNT2, SCN5A, CSRP3, LBD3, and TCAP from 313 patients with familial or idiopathic dilated cardiomyopathy.","date":"2008","source":"Clinical and translational science","url":"https://pubmed.ncbi.nlm.nih.gov/19412328","citation_count":159,"is_preprint":false},{"pmid":"18505755","id":"PMC_18505755","title":"Beyond the sarcomere: CSRP3 mutations cause hypertrophic cardiomyopathy.","date":"2008","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/18505755","citation_count":138,"is_preprint":false},{"pmid":"30930226","id":"PMC_30930226","title":"Knockdown of CSRP3 inhibits differentiation of chicken satellite cells by promoting TGF-β/Smad3 signaling.","date":"2019","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/30930226","citation_count":37,"is_preprint":false},{"pmid":"19634002","id":"PMC_19634002","title":"Porcine CSRP3: polymorphism and association analyses with meat quality traits and comparative analyses with CSRP1 and CSRP2.","date":"2009","source":"Molecular biology reports","url":"https://pubmed.ncbi.nlm.nih.gov/19634002","citation_count":34,"is_preprint":false},{"pmid":"27551448","id":"PMC_27551448","title":"Muscle LIM protein/CSRP3: a mechanosensor with a role in autophagy.","date":"2015","source":"Cell death discovery","url":"https://pubmed.ncbi.nlm.nih.gov/27551448","citation_count":34,"is_preprint":false},{"pmid":"31979369","id":"PMC_31979369","title":"The Autophagy Regulatory Molecule CSRP3 Interacts with LC3 and Protects Against Muscular Dystrophy.","date":"2020","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/31979369","citation_count":32,"is_preprint":false},{"pmid":"30703746","id":"PMC_30703746","title":"CSRP3 mediates polyphenols-induced cardioprotection in hypertension.","date":"2019","source":"The Journal of nutritional biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/30703746","citation_count":18,"is_preprint":false},{"pmid":"24279998","id":"PMC_24279998","title":"Expression, SNV identification, linkage disequilibrium, and combined genotype association analysis of the muscle-specific gene CSRP3 in Chinese cattle.","date":"2013","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/24279998","citation_count":17,"is_preprint":false},{"pmid":"30012424","id":"PMC_30012424","title":"First identification of homozygous truncating CSRP3 variants in two unrelated cases with hypertrophic cardiomyopathy.","date":"2018","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/30012424","citation_count":17,"is_preprint":false},{"pmid":"35652451","id":"PMC_35652451","title":"Vitamin C Promotes Muscle Development Mediated by the Interaction of CSRP3 with MyoD and MyoG.","date":"2022","source":"Journal of agricultural and food chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/35652451","citation_count":17,"is_preprint":false},{"pmid":"34558151","id":"PMC_34558151","title":"CSRP3, p.Arg122*, is responsible for hypertrophic cardiomyopathy in a Chinese family.","date":"2021","source":"The journal of gene medicine","url":"https://pubmed.ncbi.nlm.nih.gov/34558151","citation_count":15,"is_preprint":false},{"pmid":"22282489","id":"PMC_22282489","title":"Early depression of Ankrd2 and Csrp3 mRNAs in the polyribosomal and whole tissue fractions in skeletal muscle with decreased voluntary running.","date":"2012","source":"Journal of applied physiology (Bethesda, Md. : 1985)","url":"https://pubmed.ncbi.nlm.nih.gov/22282489","citation_count":14,"is_preprint":false},{"pmid":"35241752","id":"PMC_35241752","title":"LIM domain-wide comprehensive virtual mutagenesis provides structural rationale for cardiomyopathy mutations in CSRP3.","date":"2022","source":"Scientific 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Part A, Molecular & integrative physiology","url":"https://pubmed.ncbi.nlm.nih.gov/33548540","citation_count":6,"is_preprint":false},{"pmid":"33176267","id":"PMC_33176267","title":"CRISPR/Cas9 mediated establishment of a human CSRP3 compound heterozygous knockout hESC line to model cardiomyopathy and heart failure.","date":"2020","source":"Stem cell research","url":"https://pubmed.ncbi.nlm.nih.gov/33176267","citation_count":5,"is_preprint":false},{"pmid":"36877346","id":"PMC_36877346","title":"Identification and in silico characterization of CSRP3 synonymous variants in dilated cardiomyopathy.","date":"2023","source":"Molecular biology reports","url":"https://pubmed.ncbi.nlm.nih.gov/36877346","citation_count":4,"is_preprint":false},{"pmid":"26779824","id":"PMC_26779824","title":"Molecular cloning, characterization and tissue specificity of the expression of the ovine CSRP2 and CSRP3 genes from Small-tail Han sheep (Ovis aries).","date":"2016","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/26779824","citation_count":4,"is_preprint":false},{"pmid":"32914385","id":"PMC_32914385","title":"Discriminating aspects of global metabolism of neonatal cardiomyocytes from wild type and KO-CSRP3 rats using proton magnetic resonance spectroscopy of culture media samples.","date":"2020","source":"In vitro cellular & developmental biology. Animal","url":"https://pubmed.ncbi.nlm.nih.gov/32914385","citation_count":2,"is_preprint":false},{"pmid":"41812695","id":"PMC_41812695","title":"CSRP3 promotes skeletal muscle remodeling toward aerobic metabolism and enhances exercise endurance through increasing LDHD activity.","date":"2026","source":"Metabolism: clinical and experimental","url":"https://pubmed.ncbi.nlm.nih.gov/41812695","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.08.14.24311020","title":"Reduced Expression of MTSS1 Increases Sarcomere Number and Improves Contractility in Select Forms of Monogenic DCM","date":"2024-08-20","source":"bioRxiv","url":"https://doi.org/10.1101/2024.08.14.24311020","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.07.29.24311195","title":"ClinGen Hereditary Cardiovascular Disease Gene Curation Expert Panel: Reappraisal of Genes associated with Hypertrophic Cardiomyopathy","date":"2024-08-01","source":"bioRxiv","url":"https://doi.org/10.1101/2024.07.29.24311195","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13846,"output_tokens":2476,"usd":0.039339,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9700,"output_tokens":3254,"usd":0.064925,"stage2_stop_reason":"end_turn"},"total_usd":0.104264,"stage1_batch_id":"msgbatch_01ACAxJQabDsht39JXeWG22d","stage2_batch_id":"msgbatch_01QEU22A9U5sbPTgsMzTmvSf","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2008,\n      \"finding\": \"MLP (encoded by CSRP3) is mainly a cytosolic component of cardiomyocytes and not tightly anchored to sarcomeric structures, as demonstrated using a newly designed monoclonal antibody. At least one HCM-associated mutant form of MLP appears destabilized in the heart of HCM patients, based on in vitro and in vivo functional analyses.\",\n      \"method\": \"Monoclonal antibody immunolocalization, in vitro and in vivo functional analyses of mutant protein stability\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct antibody-based localization combined with in vitro and in vivo protein stability assays, single lab but two orthogonal approaches\",\n      \"pmids\": [\"18505755\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"MLP/CSRP3 interacts with LC3 (as shown by co-immunoprecipitation and proximity ligation assay) and is required for correct autophagosome formation and autophagic flux in C2C12 mouse myoblasts. MLP silencing decreases LC3-II staining, impairs degradation of long-lived proteins, impairs myoblast differentiation (reduced MyoD1, MyoG1, myosin heavy chain expression), and increases susceptibility to apoptosis (increased caspase-3 and PARP cleavage).\",\n      \"method\": \"Co-immunoprecipitation, proximity ligation assay (PLA), siRNA silencing and overexpression in C2C12 cells, LC3-II immunostaining, long-lived protein degradation assay, ultrastructural analysis, caspase/PARP cleavage assay\",\n      \"journal\": \"Cell death discovery\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP plus PLA plus multiple functional readouts, single lab\",\n      \"pmids\": [\"27551448\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Knockdown of CSRP3 in chicken satellite cells inhibits their differentiation into myotubes without affecting proliferation. The mechanism involves upregulation of TGF-β and Smad3 mRNA and protein, and increased phosphorylation of Smad3 during differentiation.\",\n      \"method\": \"siRNA knockdown in primary chicken satellite cells, qPCR and western blot for TGF-β/Smad3 pathway components, differentiation assay (myotube formation at 24/48/72 h)\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA loss-of-function with defined cellular phenotype and pathway placement via Smad3 phosphorylation, single lab, two orthogonal methods (qPCR + western)\",\n      \"pmids\": [\"30930226\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CSRP3 interacts with LC3 protein to promote autophagosome formation during autophagy in chicken primary myoblasts. CSRP3 silencing impairs autophagy (reduced ATG5, ATG7 mRNA, and LC3-II and Beclin-1 protein levels), increases apoptosis (elevated caspase-3 and caspase-9 cleavage), and these effects are alleviated by autophagy activation.\",\n      \"method\": \"siRNA knockdown in chicken primary myoblasts, co-immunoprecipitation (CSRP3–LC3 interaction), western blot and qPCR for autophagy markers, caspase cleavage assay, autophagy activator rescue experiment\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus multiple functional readouts plus rescue experiment, single lab; replicates finding from PMID:27551448\",\n      \"pmids\": [\"31979369\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"CSRP3 promotes myoblast differentiation by undergoing nuclear translocation in response to vitamin C, after which it interacts with the myogenic transcription factors MyoD and MyoG to promote muscle development and muscle injury repair in mice.\",\n      \"method\": \"Cell and molecular biology, proteomics, nuclear fractionation/localization imaging, co-immunoprecipitation of CSRP3 with MyoD and MyoG, C2C12 differentiation assay, mouse muscle injury model\",\n      \"journal\": \"Journal of agricultural and food chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus localization plus in vivo injury model, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"35652451\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"CSRP3 is a target of the polyphenol metabolite 4-methylcatechol sulfate in cardiomyocytes. siRNA silencing of CSRP3 reverses phenylephrine-induced cardiomyocyte hypertrophy, and CSRP3 overexpression induces hypertrophy, establishing CSRP3 as a mediator of cardiomyocyte hypertrophic responses.\",\n      \"method\": \"siRNA silencing and overexpression in neonatal rat ventricular cardiomyocytes, phenylephrine-induced hypertrophy model, proteomics identification, 4-methylcatechol sulfate treatment\",\n      \"journal\": \"The Journal of nutritional biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss- and gain-of-function in primary cardiomyocytes with defined phenotypic readout, single lab, two orthogonal approaches (KD + OE)\",\n      \"pmids\": [\"30703746\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Computational virtual mutagenesis and molecular dynamics simulations show that the HCM/DCM-associated L44P mutation in the LIM domain of CSRP3 destabilizes the domain by altering secondary structure and disrupting a hydrophobic interaction with Phenylalanine 35, whereas the neutral L44M substitution does not have this effect.\",\n      \"method\": \"In silico mutational landscape mapping, molecular dynamics (MD) simulations, sequence and structural analysis of LIM domains\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — purely computational, no experimental validation of predicted structural effects\",\n      \"pmids\": [\"35241752\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"CSRP3 binds to D-lactate dehydrogenase (LDHD) via a specific 33-amino acid region, promoting D-lactate metabolism in skeletal muscle. This interaction regulates mitochondrial morphology, biogenesis, oxidative phosphorylation efficiency, and TCA cycle activity, driving skeletal muscle mitochondrial metabolic rewiring and fiber type remodeling toward oxidative (aerobic) myofibers. AAV-mediated CSRP3 knockdown perturbs mitochondrial energy metabolism, reduces oxidative fiber proportion, and compromises exercise performance.\",\n      \"method\": \"Co-immunoprecipitation (CSRP3–LDHD), domain mapping (33-aa region), AAV-mediated knockdown in live mice, mitochondrial function assays, myofiber type analysis, exercise performance testing\",\n      \"journal\": \"Metabolism: clinical and experimental\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP with domain mapping plus in vivo AAV knockdown with multiple metabolic readouts, single lab\",\n      \"pmids\": [\"41812695\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Csrp3 mRNA and protein levels decline in rat skeletal muscle following removal of voluntary running (wheel-lock model), identifying CSRP3 as a mechano-sensitive gene whose expression is regulated by mechanical loading in skeletal muscle.\",\n      \"method\": \"Affymetrix microarray of polyribosomal fraction, RT-PCR verification, whole-tissue mRNA and protein quantification across multiple time points after wheel-lock\",\n      \"journal\": \"Journal of applied physiology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — expression-level readout with RT-PCR and protein validation, but no direct mechanistic intervention; establishes mechano-sensitivity but not molecular mechanism\",\n      \"pmids\": [\"22282489\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CSRP3/MLP is a cytosolic, muscle-specific LIM-domain protein that functions as a mechanosensor and structural regulator in cardiac and skeletal muscle: it promotes autophagosome formation by directly binding LC3, drives myogenic differentiation by translocating to the nucleus and interacting with MyoD and MyoG, suppresses cardiomyocyte hypertrophy, modulates TGF-β/Smad3 signaling to support satellite cell differentiation, and enhances skeletal muscle aerobic metabolism by binding LDHD to promote D-lactate metabolism and mitochondrial biogenesis; disease-causing missense mutations destabilize its LIM domains, and loss of CSRP3 causes dilated or hypertrophic cardiomyopathy.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CSRP3 (MLP) is a muscle-specific LIM-domain protein that acts as a structural and regulatory hub in cardiac and skeletal muscle, coordinating autophagy, myogenic differentiation, metabolic remodeling, and hypertrophic responses [#1, #4, #7]. In cardiomyocytes it is predominantly cytosolic rather than tightly anchored to sarcomeric structures, and at least one HCM-associated mutant form is destabilized in patient hearts [#0]. CSRP3 directly binds LC3 to promote autophagosome formation and sustain autophagic flux; its loss impairs autophagy, blocks myoblast differentiation, and sensitizes cells to apoptosis [#1, #3]. During differentiation CSRP3 translocates to the nucleus and engages the myogenic transcription factors MyoD and MyoG to drive muscle development and injury repair [#4], and it supports satellite cell differentiation by restraining TGF-\\u03b2/Smad3 signaling [#2]. In skeletal muscle CSRP3 binds D-lactate dehydrogenase (LDHD) through a defined 33-amino-acid region to promote D-lactate metabolism, mitochondrial biogenesis, oxidative phosphorylation, and a shift toward oxidative myofibers, with in vivo knockdown compromising exercise performance [#7]. In the heart CSRP3 mediates hypertrophic responses, as silencing reverses and overexpression induces cardiomyocyte hypertrophy [#5]. Its expression is mechanically regulated, declining when mechanical loading is withdrawn [#8].\",\n  \"teleology\": [\n    {\n      \"year\": 2008,\n      \"claim\": \"Established that MLP is mainly cytosolic in cardiomyocytes rather than a rigidly sarcomere-anchored protein, and linked disease mutations to protein destabilization, reframing how its function and pathogenicity should be interpreted.\",\n      \"evidence\": \"Monoclonal antibody immunolocalization plus in vitro and in vivo mutant stability assays in cardiomyocytes\",\n      \"pmids\": [\"18505755\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Does not define the cytosolic binding partners that retain MLP\", \"Mechanistic basis of mutant destabilization not resolved at structural level\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Identified CSRP3 as a mechano-sensitive gene by showing its expression tracks mechanical loading, connecting it to load-dependent muscle adaptation.\",\n      \"evidence\": \"Microarray of polyribosomal fraction with RT-PCR and protein validation in rat wheel-lock model\",\n      \"pmids\": [\"22282489\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Expression correlation only, no molecular mechanism of mechanotransduction\", \"Does not show CSRP3 is causal in the adaptive response\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined a direct CSRP3\\u2013LC3 interaction required for autophagosome formation and linked autophagy competence to myoblast differentiation and survival, placing CSRP3 in the autophagy machinery.\",\n      \"evidence\": \"Reciprocal co-IP, PLA, siRNA/overexpression with LC3-II, protein degradation, differentiation, and caspase/PARP readouts in C2C12 cells\",\n      \"pmids\": [\"27551448\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"LC3 binding interface on CSRP3 not mapped\", \"Whether autophagy defect is the proximate cause of impaired differentiation not separated from other roles\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Showed CSRP3 supports satellite cell differentiation by restraining the TGF-\\u03b2/Smad3 axis, providing a signaling mechanism for its pro-differentiation effect.\",\n      \"evidence\": \"siRNA knockdown in primary chicken satellite cells with qPCR/western for TGF-\\u03b2/Smad3 and myotube formation assay\",\n      \"pmids\": [\"30930226\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No demonstrated direct interaction linking CSRP3 to TGF-\\u03b2/Smad3 components\", \"Whether Smad3 modulation is direct or downstream of autophagy/transcriptional roles unknown\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Demonstrated CSRP3 is a causal mediator of cardiomyocyte hypertrophy, with loss reversing and gain inducing the hypertrophic phenotype.\",\n      \"evidence\": \"siRNA silencing and overexpression in neonatal rat ventricular cardiomyocytes under phenylephrine-induced hypertrophy\",\n      \"pmids\": [\"30703746\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Downstream effectors of CSRP3-driven hypertrophy not identified\", \"Relationship to its autophagy and metabolic roles not integrated\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Replicated the CSRP3\\u2013LC3 autophagy mechanism in an independent species and showed autophagy activation rescues the apoptotic phenotype, strengthening the autophagy-promoting role.\",\n      \"evidence\": \"Co-IP, siRNA knockdown, autophagy/apoptosis markers, and autophagy activator rescue in chicken primary myoblasts\",\n      \"pmids\": [\"31979369\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Binding region still unmapped\", \"Does not address the cardiac context\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Revealed a nuclear, transcriptional arm of CSRP3 function: stimulus-induced nuclear translocation and interaction with MyoD and MyoG to drive myogenesis and injury repair.\",\n      \"evidence\": \"Nuclear fractionation/imaging, co-IP with MyoD and MyoG, C2C12 differentiation, and mouse muscle injury model\",\n      \"pmids\": [\"35652451\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism triggering nuclear translocation beyond vitamin C stimulus unclear\", \"Whether CSRP3 directly modulates MyoD/MyoG target transcription not shown\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Provided a structural rationale for pathogenicity by showing the HCM/DCM L44P mutation destabilizes the LIM domain via disrupted hydrophobic packing, while a neutral substitution does not.\",\n      \"evidence\": \"In silico virtual mutagenesis and molecular dynamics simulations of the LIM domain\",\n      \"pmids\": [\"35241752\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Purely computational with no experimental validation of predicted destabilization\", \"Does not connect destabilization to a specific functional loss\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Connected CSRP3 to skeletal muscle energy metabolism by mapping a 33-aa LDHD-binding region that drives D-lactate metabolism, mitochondrial biogenesis, oxidative fiber remodeling, and exercise capacity.\",\n      \"evidence\": \"Co-IP with domain mapping, AAV-mediated knockdown in mice, mitochondrial function and myofiber-type assays, exercise testing\",\n      \"pmids\": [\"41812695\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How LDHD binding mechanistically alters mitochondrial biogenesis is not resolved\", \"Integration with autophagic and transcriptional roles unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How CSRP3 coordinates its distinct cytosolic (autophagy, metabolism), nuclear (myogenic transcription), and hypertrophy-modulating activities into a unified mechanosensing program remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structure of CSRP3 bound to LC3, LDHD, or MyoD/MyoG\", \"Signals partitioning CSRP3 between cytosol and nucleus not defined\", \"Causal link between LIM-domain destabilization and specific functional losses not experimentally established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [1, 3, 7]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [1, 3]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [2, 4]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [7]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"LC3\", \"MyoD\", \"MyoG\", \"LDHD\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}