Rat Caldesmon (CALD1) Protein

Background

CALD1 (Caldesmon 1) is a versatile actin-binding protein predominantly expressed in smooth muscle and non-muscle cells, where it plays a key role in modulating cytoskeletal dynamics and cellular contractility. CALD1 interacts with actin filaments, myosin, tropomyosin, and calmodulin, acting as a regulatory mediator of actomyosin interactions crucial for cellular processes such as contraction, migration, and shape changes. In smooth muscle cells, CALD1 contributes to the regulation of contraction by inhibiting the ATPase activity of myosin in a calcium-calmodulin-dependent manner, thereby modulating muscle tone and elasticity. In non-muscle cells, it is implicated in stabilizing the cytoskeleton and facilitating cell motility, often in response to signaling cascades that control cell migration and adhesion. CALD1 has also been associated with cancer progression, where its expression is frequently altered, contributing to tumor invasiveness and metastasis by influencing cytoskeletal reorganization and cellular dynamics. Its phosphorylation state, regulated by various kinases, fine-tunes its interaction with actin and myosin, enabling precise control over cytoskeletal remodeling. These multifunctional attributes make CALD1 a critical player in maintaining cellular integrity and adaptability across different physiological and pathological contexts.