In addition to their roles in organizing the actin cytoskeleton, members of the Rho family of GTP-binding proteins have recently been implicated in a plethora of other functions, including the activation of kinase cascades and transcription factors, and the control of endocytosis and secretion. Alongside this expansion is proposed functions has been the identification of multiple target proteins that interact directly with Rho, Rac or Cdc42. Molecular connections are now being made along the signalling pathways activated by members of the Rho family.