P21 activated kinases: structure, regulation, and functions

Small GTPases. 2014;5:e28003. doi: 10.4161/sgtp.28003. Epub 2014 Mar 21.


The p21 activated kinases (Paks) are well known effector proteins for the Rho GTPases Cdc42 and Rac. The Paks contain 6 members, which fall into 2 families of proteins. The first family consists of Paks 1, 2, and 3, and the second consists of Paks 4, 5, and 6. While some of the Paks are ubiquitously expressed, others have more restrictive tissue specificity. All of them are found in the nervous system. Studies using cell culture, transgenic mice, and knockout mice, have revealed important roles for the Paks in cytoskeletal organization and in many aspects of cell growth and development. This review discusses the basic structures of the Paks, and their roles in cell growth, development, and in cancer.

Keywords: neurobiology; oncogenesis; p21-activated kinases; pak; protein kinases; substrates.

Publication types

  • Review

MeSH terms

  • Animals
  • Cytoskeleton / metabolism
  • Gene Expression
  • Humans
  • Neoplasms / enzymology
  • Neoplasms / metabolism
  • Neoplasms / pathology
  • Signal Transduction
  • cdc42 GTP-Binding Protein / metabolism
  • p21-Activated Kinases / chemistry
  • p21-Activated Kinases / genetics
  • p21-Activated Kinases / metabolism*
  • rac GTP-Binding Proteins / metabolism
  • rho GTP-Binding Proteins / metabolism


  • p21-Activated Kinases
  • cdc42 GTP-Binding Protein
  • rac GTP-Binding Proteins
  • rho GTP-Binding Proteins