Association of PI-3 Kinase with PAK1 Leads to Actin Phosphorylation and Cytoskeletal Reorganization
AUTOR(ES)
Papakonstanti, Evangelia A.
FONTE
The American Society for Cell Biology
RESUMO
The family of p21-activated kinases (PAKs) have been implicated in the rearrangement of actin cytoskeleton by acting downstream of the small GTPases Rac and Cdc42. Here we report that even though Cdc42/Rac1 or Akt are not activated, phosphatidylinositol-3 (PI-3) kinase activation induces PAK1 kinase activity. Indeed, we demonstrate that PI-3 kinase associates with the N-terminal regulatory domain of PAK1 (amino acids 67–150) leading to PAK1 activation. The association of the PI-3 kinase with the Cdc42/Rac1 binding-deficient PAK1(H83,86L) confirms that the small GTPases are not involved in the PI-3 kinase-PAK1 interaction. Furthermore, PAK1 was activated in cells expressing the dominant-negative forms of Cdc42 or Rac1. Additionally, we show that PAK1 phosphorylates actin, resulting in the dissolution of stress fibers and redistribution of microfilaments. The phosphorylation of actin was inhibited by the kinase-dead PAK1(K299R) or the PAK1 autoinhibitory domain (PAK1(83–149)), indicating that PAK1 was responsible for actin phosphorylation. We conclude that the association of PI-3 kinase with PAK1 regulates PAK1 kinase activity through a Cdc42/Rac1-independent mechanism leading to actin phosphorylation and cytoskeletal reorganization.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=117954Documentos Relacionados
- Yeast Pak1 Kinase Associates with and Activates Snf1
- Human Immunodeficiency Virus Type 1 Tat Regulates Endothelial Cell Actin Cytoskeletal Dynamics through PAK1 Activation and Oxidant Production
- High-fat feeding increases insulin receptor and IRS-1 coimmunoprecipitation with SOCS-3, IKKα/β phosphorylation and decreases PI-3 kinase activity in muscle
- Pak1 Protein Kinase Regulates Activation and Nuclear Localization of Snf1-Gal83 Protein Kinase
- Kinase-deficient Pak1 mutants inhibit Ras transformation of Rat-1 fibroblasts.