Protein kinases comprise a large group of encoded factors that regulate cellular processes by catalyzing the transfer of a phosphate group to a hydroxyl acceptor in serine, threonine or tyrosine residues. Myotonic dystrophy kinaserelated Cdc42-binding (DMPK-like) kinases-alpha and beta (MRCK-alpha, beta) contain a cysteine-rich motif and a putative pleckstrin homology domain. MRCKs can phosphorylate nonmuscle Myosin light chain and influences Actin-Myosin contractility. MRCK-alpha can phosphorylate and activate LIM kinases downstream of Cdc42, which leads to inactivation of ADF/Cofilin and to Actin cytoskeletal reorganization. MRCK-alpha can also influence neurite outgrowth promoted by Cdc42 and Rac.