Regulates a signal transduction pathway linking plasma membrane receptors to the assembly of focal adhesions and actin stress fibers. Serves as a microtubule-dependent signal that is required for the myosin contractile ring formation during cell cycle cytokinesis. Regulates apical junction formation in bronchial epithelial cells (By similarity). Interacts with RTKN. Interacts with AKAP13. Interacts with DIAPH1. Interacts with PKN2. Interacts with ROCK1 and ROCK2. Interacts with ARHGDIA. Interacts with RIPOR1. Translocates to the equatorial region before furrow formation in a ECT2-dependent manner. Belongs to the small GTPase superfamily. Rho family.