The PAK (p21-activated kinase) family of serine/threonine kinases plays an important role in multiple cellular processes, including cytoskeletal reorganization, MAPK signaling, apoptotic signaling, etc. PAK 5 is known for promoting neurite outgrowth and thus predominantly expressed in the brain. PAK 5 contains CDC42/Rac1and has shown to bind CDC42 in the presence of GTP. PAK 5 also plays an important role in inhibiting apoptotic cascade throμgh BAD phosphorylation.