Regulation of Cytoskeleton and Cell Adhesions by the Small GTPase Rho and Its Targets

The Rho GTPase is a member of the Rho family, which belongs to the Ras superfamily of GTP-binding proteins. Like other GTP-binding proteins, Rho exhibits both GDP/GTP-binding activities and functions as a molecular switch, cycling between an inactive GDP-bound state and an active GTP-bound state. Rho regulates the actin cytoskeleton and cell adhesions through its specific targets. Rho is also involved in the regulation of cell morphology, cell motility, cytokinesis, and smooth muscle contraction. Until recently, however, the molecular mechanism by which Rho regulates these functions remained to be clarified. A lot of targets of Rho have recently been identified, and characterization of some of them has provided useful information for our understanding of Rho functions. This review is an attempt to focus on the roles of Rho and its targets in the regulation of the cytoskeletons and cell adhesions.