The Ras superfamily of GTPases comprises more than 50 members. Whereas Ras is known to play a central role in cell proliferation, the Rho-family of Ras-related small GTP-binding proteins have been shown to regulate several aspects of cytoskeleton functioning. Recently, we and others have shown that members of the Rho-family of GTPases also control signaling cascades communicating the membrane to the nucleus, and that these GTP-binding proteins are integral components of growth-regulatory pathways. In this article, we will focus on the recent identification of molecules linking the Rho-family of GTPases to the cytoskeleton and to signaling kinase cascades.