Rho protein crosstalk: another social network?

Many fundamental processes in cell biology are regulated by Rho GTPases, including cell adhesion, migration and differentiation. While regulating cellular functions, members of the Rho protein family cooperate or antagonize each other. The resulting molecular network exhibits many levels of interaction dynamically regulated in time and space. In the first part of this review we describe the main mechanisms of this crosstalk, which can occur at three different levels of the pathway: (i) through regulation of activity, (ii) through regulation of protein expression and stability, and (iii) through regulation of downstream signaling pathways. In the second part we illustrate the importance of Rho protein crosstalk with two examples: integrin-based adhesion and cell migration.