N-terminal domains depicted are in pale blue — WASP homology 1 (WH1); WAVE homology domain (WHD); WASH homology domain (WAHD) and the WHAMM membrane interaction domain (WM) or N-terminal domain (N). Other domains are: B, basic region; GBD, GTPase-binding domain; CC, coiled coil region; P, proline-rich domain; W, the WASP homology-2 (WH2) domain; C, the connecting or central domain; A, acidic domain. W, C and A together are referred to as the WCA domain. In general, the N-terminal domains are thought to confer spatiotemporal regulation on the protein, while the WCA regions at the C-terminal are required for activation of Arp2/3.