MRCK (Myotonic Dystrophy Kinase-Related Cdc42-Binding Kinase) is a serine/threonine kinase that binds to the Rho family GTPase Cdc42. The MRCK family includes MRCKα, MRCKβ, and MRCKγ. These kinases are primarily localized in the cytoplasm and are involved in regulating cytoskeletal reorganization, cell migration, and muscle cell contraction. MRCK influences these biological processes by activating Cdc42-associated signaling pathways. Gene expression is tissue-specific, and mutations may affect cellular dynamics and the development of related diseases.