{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nXIRP1, also known as Xin or cardiomyopathy‐associated gene 1 (CMYA1), is a striated muscle–specific protein that plays a central role in establishing and stabilizing the actin cytoskeleton during muscle development. It is predominantly localized to key structural domains such as the intercalated discs in cardiomyocytes and the myotendinous junctions in skeletal muscle, where unique 16–amino acid repeats mediate direct binding to actin filaments and promote network formation. Through interactions with proteins such as filamin C, Mena, VASP, and nebulin/nebulette, XIRP1 is critical for orchestrating myofibril assembly and maintaining cytoskeletal architecture during both early developmental stages and adaptive remodeling processes."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "4"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn addition to its structural functions, XIRP1 is intimately involved in muscle repair and pathology. Its expression is markedly upregulated in injured skeletal muscle and correlates with the severity of muscle damage, serving as a reliable biomarker for myopathy. Immunohistochemical analyses of myofibrillar myopathies also reveal abnormal localization of XIRP1 and other stress‐responsive Z-disc proteins, which underscores its role in compensatory remodeling processes required to maintain muscle integrity."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond its contribution to cytoskeletal organization and repair, XIRP1 is essential for maintaining electrical and mechanical stability in the heart. It supports the structural integrity of intercalated discs by regulating the plasma membrane expression of key ion channels, and alterations in XIRP1 are linked to arrhythmogenic disorders such as sudden unexplained nocturnal death syndrome. Moreover, mutations or abnormal expression of the CMYA1/XIRP1 gene have been implicated in congenital cardiomyopathies as well as in tumor-suppressor pathways in head and neck squamous cell carcinoma, indicating that the protein’s regulatory functions extend to both developmental and disease contexts."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "7", "end_ref": "10"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Dirk Pacholsky, Padmanabhan Vakeel, Mirko Himmel, et al. 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"}, {"type": "b", "children": [{"type": "t", "text": "Unusual splicing events result in distinct Xin isoforms that associate differentially with filamin c and Mena/VASP."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Exp Cell Res (2006)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.yexcr.2006.03.015"}], "href": "https://doi.org/10.1016/j.yexcr.2006.03.015"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16631741"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16631741"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Stefan Eulitz, Florian Sauer, Marie-Cecile Pelissier, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Identification of Xin-repeat proteins as novel ligands of the SH3 domains of nebulin and nebulette and analysis of their interaction during myofibril formation and remodeling."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Biol Cell (2013)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1091/mbc.E13-04-0202"}], "href": "https://doi.org/10.1091/mbc.E13-04-0202"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "23985323"}], "href": "https://pubmed.ncbi.nlm.nih.gov/23985323"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Sibylle Molt, John B Bührdel, Sergiy Yakovlev, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Aciculin interacts with filamin C and Xin and is essential for myofibril assembly, remodeling and maintenance."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Cell Sci (2014)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1242/jcs.152157"}], "href": "https://doi.org/10.1242/jcs.152157"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "24963132"}], "href": "https://pubmed.ncbi.nlm.nih.gov/24963132"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Kristl G Claeys, Peter F M van der Ven, Anthony Behin, et al. 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