Q13153, Q13177, O75914

The alpha, beta, and gamma PAK isoforms, which are serine/threonine kinases, play a crucial role in cellular signaling pathways by interacting with the small GTPases Rac1 and Cdc42. These interactions are vital for regulating cytoskeletal dynamics and cell motility, processes that are essential for various physiological functions, including cell migration, proliferation, and differentiation. Notably, γPAK has eight autophosphorylation sites, with phosphorylation at Ser 141 and Thr 402 being particularly important for activation. Upon activation, γPAK can dissociate from Rac1 and Cdc42 complex, allowing phosphorylation of downstream substrates such as Mek kinase, which is a key player in the JNK signaling pathway. This intricate regulation of signaling pathways underscores the importance of PAK proteins in maintaining cellular homeostasis and responding to external stimuli.