ROCK1 is a member of the AGC serine/threonine protein kinase family that regulates the assembly of the actin cytoskeleton. ROCK1 contains a protein kinase domain, a coiled-coil region and a zinc finger region and appears to be present as a dimer. ROCK1, like its isozyme ROCK2, is a downstream target of the small G-protein Rho and plays a role in smooth muscle contraction, malignant cell transformation, tumor invasion and metastasis, and mediates the cellular morphological changes during apoptosis.