PAK1, a member of the STE20 subfamily of Ser/Thr protein kinases, acts on a variety of targets. It is likely to be the GTPase effector that links the Rho-related GTPases to the JNK MAP kinase pathway. Activity is inhibited in cells undergoing apoptosis, potentially due to binding of CDC2L1 and CDC2L2. The protein interacts tightly with GTP-bound but not GDP-bound CDC42/P21 and RAC1. PAK1 binds to the caspase-cleaved p110 isoform of CDC2L1 and CDC2L2, p110C, but not the full-length proteins. It is a component of cytoplasmic complexes, which also contain PXN, ARHGEF6 and GIT1. The protein is autophosphorylated when activated by CDC42/p21. Structurally, the PAK1 contains 1 CRIB domain.

2-8°C (short-term); -20°C (long-term)