p21 Protein Activated Kinase 1 (PAK1)

PAK proteins are critical effectors that link RhoGTPases to cytoskeleton reorganization and nuclear signaling. PAK proteins, a family of serine/threonine p21-activating kinases, include PAK1, PAK2, PAK3 and PAK4. These proteins serve as targets for the small GTP binding proteins Cdc42 and Rac and have been implicated in a wide range of biological activities. PAK1 regulates cell motility and morphology.

PAK1 is a member of a family of serine/threonine kinases related to yeast Ste20. The human PAK1 gene encodes a 545-amino acid polypeptide that is 98% identical to rat PAK1 and 52% identical to yeast Ste20. Activity of PAK1 is induced by coexpression with RAC1 or CDC42. PAK is believed to act directly on the JNK1 MAP kinase pathway.