WASp

WASp is a multi-domain protein containing Rho GTPase binding domain (RBD), an actin binding domain and an Arp2/Arp3 complex binding domain. When not bound to Rho, the RBD prevents binding to the Arp2/Arp3 complex. When Cdc42 GTPase becomes activated, WASp is recruited to the plasmamembrane. This causes a conformational shift which releases the Arp2/Arp3 binding domain to trigger branch formation.