Figure 1. Representation of the structural domains of Nck, WASp/WAVE proteins and their critical interactions. (A) Nck consists of three N-terminal SH3 domains and a C-terminal SH2 domain. The consensus sequence of peptides found in proteins that bind Nck via SH2- or SH3-mediated interactions and well characterized Nck binding partners are shown. (B) Members of the WASP/WAVE families of nucleation promoting factors consist of a conserved C-terminus that enables interactions with G-actin and the Arp2/3 complex (VCA) and SH3 domains (proline-rich). Members from both families possess a polybasic motif (++) that mediates interaction/regulation by phosphoinositides. In cells, WASp proteins form a complex with WASp-interacting protein (WIP) whereas WAVE/Scar proteins are found as a complex that also includes Pir 121, Nap 1, Abi-1, and HSP300 (not shown).