Rho GTPases and the control of cell behaviour

Rho, Rac and Cdc42, three members of the Rho family of small GTPases, each control a signal transduction pathway linking membrane receptors to the assembly and disassembly of the actin cytoskeleton and of associated integrin adhesion complexes. Rho regulates stress fibre and focal adhesion assembly, Rac regulates the formation of lamellipodia protrusions and membrane ruffles, and Cdc42 triggers filopodial extensions at the cell periphery. These observations have led to the suggestion that wherever filamentous actin is used to drive a cellular process, Rho GTPases are likely to play an important regulatory role. Rho GTPases have also been reported to control other cellular activities, such as the JNK (c-Jun…