Rho activation at a glance

Cells receive a multitude of stimuli – chemical (such as cytokines and growth factors) and physical (such as mechanical stresses or adhesion to extracellular matrix or other cells) – that influence cell function by affecting intracellular signaling pathways. Very often these stimuli involve cell surface receptors or other molecules that function through activation of the Rho family of small GTPases. Rho GTPases control multiple cellular processes, including actin and microtubule dynamics, gene expression, the cell cycle, cell polarity and membrane transport, through their ability to bind to numerous downstream effectors, which lead to diverse parallel downstream signaling pathways (Schwartz, 2004). Over 20 members of the Rho family have been identified in mammalian cells (Wennerberg and Der, 2005). These are represented here by the canonical proteins Rho, Rac and Cdc42 and have been the subject of numerous excellent reviews