The WASP-Arp2/3 pathway: genetic insights.

Arp2/3 complex nucleates the formation of dendritic actin filament arrays, which are especially prominent at the leading edges of motile cells. Recent genetic and other loss-of-function studies have highlighted the importance of the Arp2/3 complex for normal cell functions, and especially for cell motility. WASP/Scar family proteins regulate the activity of the Arp2/3 complex, and also link it to several signaling pathways. Recent studies suggest that Scar is a more important regulator of Arp2/3 activity in actin-dependent morphological processes than WASP, which may have a more restricted role in specialized cellular events. It has also become clear that precise regulation of both Scar and WASP activity is of the utmost importance for their physiological functions.