Meta-Biol

• Pathways

The ARP2/3 complex shows higher affinity for the phosphorylated VCA domain of WAVE2 than for the unphosphorylated VCA domain. WAVE proteins can be phosphorylated by various kinases. Active ERK (Mitogen activated protein kinase 3) phosphorylates the WAVE regulatory complex (WRC) on multiple serine/threonine sites within the proline-rich domains (PRDs) of WAVE2 and ABI1. Phosphorylation of the PRDs would disrupt their interaction with SH3 and PLP binding domains, potentially altering WRC activation. ERK phosphorylates both S343 and T346 in WAVE2 and S183, S216, S225, S392, and S410 in ABI1. Cumulatively, the phosphorylation of both WAVE2 and ABI in the WAVE regulatory complex (WRC) contributes to the RAC-induced WRC conformational change that exposes the VCA domain, leading to binding and activation of ARP2/3 (Mendoza et al. 2011, Nakanishi et al. 2007). ERK phosphorylation sites in WAVE2 are not strictly conserved in WAVE1 and WAVE3 but, based on the amino acid sequence, other potential ERK phosphorylation sites exist.