Cdc42: new roads to travel

The roles of Cdc42 in stimulating changes in the actin cytoskeleton and in the establishment of cell polarity have been known for some time. However, evidence implicating Cdc42 in intracellular trafficking and in the regulation of cell growth have continued to surface. Recently, exciting developments have highlighted how Cdc42 might participate in these cellular functions by regulating the processing of the EGF receptor. Here, I discuss these findings within the broader context of how Cdc42 serves as a multifaceted signaling switch that links trafficking events to the control of cell growth.