Phosphoinositides and several Rab GTPases regulate vesicle trafficking and membrane fusion . Vaccinia actin movement is also dependent on the small GTPase Rac1 and its downstream effector, formin-type actin nucleation factor FHOD . The large GTPase dynamin controls the formation and motility of actin comets in living cells and plays a crucial role in actin-based vesicle motility . Numerous virus have adapted multiple interactions with Rho GTPase signaling for their own benefit . Rah co-localizes with actin on membrane ruffles and the membrane of larger vesicles adjacent to membrane ruffles in fibroblasts . Large cytoplasmic bodies made of actin move toward the cell center from membrane ruffles on the cell surface .