A family of serine/threonine protein kinases of the STE20 group. PAK1 (545 aa) homodimers show transinhibition but dissociate and are activated by GTP-cdc42 or GTP-rac1 and are then able to act on various targets. PAK1 binds to the SH3 domains of phospholipase Cγ and of Nck, and promotes the disassembly of stress fibres and focal adhesions. PAK2 (507 aa) can be activated by rac or cdc42 and stimulates cell survival, but a caspase-generated constitutively active catalytic fragment induces an apoptotic response. PAK3 (oligophrenin 3, 559 aa) has three tissue-restricted isoforms, and mutations in PAK3 are associated with X-linked mental retardation-30.
Subjects: Medicine and Health.