Unlocking the Role of sMyBP-C: A Key Player in Skeletal Muscle Development and Growth.

Skeletal muscle is the largest organ in the body, responsible for gross movement and metabolic regulation. Recently, variants in the gene have been implicated in a variety of developmental muscle diseases, such as distal arthrogryposis. How variants cause disease is not well understood. Here, through a collection of novel gene-edited mouse models, we define a critical role for slow myosin binding protein-C (sMyBP-C), encoded by , across muscle development, growth, and maintenance during prenatal, perinatal, postnatal and adult stages. Specifically, knockout mice exhibited early postnatal lethality and impaired skeletal muscle formation and structure, skeletal deformity, and respiratory failure. Moreover, a conditional knockout of in perinatal, postnatal and adult stages demonstrates impaired postnatal muscle growth and function secondary to disrupted actomyosin interaction and sarcomere structural integrity. These findings confirm the essential role of sMyBP-C in skeletal muscle and reveal specific functions in both prenatal embryonic musculoskeletal development and postnatal muscle growth and function.