This entry represents the catalytic domain of serine/threonine kinase p21-activated kinase (PAK) 3.PAK3 is highly expressed in the brain. It is implicated in neuronal plasticity, synapse formation, dendritic spine morphogenesis, cell cycle progression, neuronal migration, and apoptosis [, ]. Inactivating mutations in the PAK3 gene cause X-linked non-syndromic mental retardation, the severity of which depends on the site of the mutation [, ]. PAK3 belongs to the group I PAKs.Group I PAKs contain a PBD (p21-binding domain) overlapping with an AID (autoinhibitory domain), a C-terminal catalytic domain, SH3 binding sites and a non-classical SH3 binding site for PIX (PAK-interacting exchange factor). PAKs are Rho family GTPase-regulated kinases that serve as important mediators in the function of Cdc42 (cell division cycle 42) and Rac [].
