p21 activated kinases (PAKs) are members of a family of enzymes.^[1] They serve as targets for the small GTP binding proteins CDC42 and Rac and have been implicated in a wide range of biological activities.

Members include:

• PAK1, regulating cell motility and morphology^[2]
• PAK2, possibly playing a role in apoptosis^[3]
• PAK3, possibly for dendritic development and for the rapid cytoskeletal reorganization in dendritic spines associated with synaptic plasticity^[4]
• PAK4, a mediator of filopodia formation^[5]
• PAK5, a mediator of filopodia formation^[6]
• PAK6, involved in cytoskeleton rearrangement^[7]