p21-activated kinase 1 phosphorylates the death agonist bad and protects cells from apoptosis.
Bad is a critical regulatory component of the intrinsic cell death machinery that exerts its death-promoting effect upon heterodimerization with the antiapoptotic proteins Bcl-2 and Bcl-x(L). Growth factors promote cell survival through phosphorylation of Bad, resulting in its dissociation from Bcl-2 and Bcl-x(L) and its association with 14-3-3tau. Survival of interleukin 3 (IL-3)-dependent FL5.12 lymphoid progenitor cells is attenuated upon treatment with the Rho GTPase-inactivating toxin B from Clostridium difficile. p21-activated kinase 1 (PAK1) is activated by IL-3 in FL5.12 cells, and this activation is reduced by the phosphatidylinositol 3-kinase inhibitor LY294002. Overexpression of a constitutively active PAK mutant (PAK1-T423E) promoted cell survival of FL5.12 and NIH 3T3 cells, while overexpression of the autoinhibitory domain of PAK (amino acids 83 to 149) enhanced apoptosis. PAK phosphorylates Bad in vitro and in vivo on Ser112 and Ser136, resulting in a markedly reduced interaction between Bad and Bcl-2 or Bcl-x(L) and the increased association of Bad with 14-3-3tau. Our findings indicate that PAK inhibits the proapoptotic effects of Bad by direct phosphorylation and that PAK may play an important role in cell survival pathways.
Schürmann
A
A
Institut für Pharmakologie und Toxikologie, Medizinische Fakulät, Rheinisch-Westfälische Technische Hochschule Aachen, D52057 Aachen, Germany.
Mooney
A F
AF
Sanders
L C
LC
Sells
M A
MA
Wang
H G
HG
Reed
J C
JC
Bokoch
G M
GM
D048948:14-3-3 Proteins; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D007377:Interleukin-3 / Q000494:pharmacology; D051379:Mice; D009154:Mutation / Q000235:genetics; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D054462:p21-Activated Kinases; D020741:rho GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism
D048948:14-3-3 Proteins; D002352:Carrier Proteins; D007377:Interleukin-3; D010446:Peptide Fragments; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010768:Phosphoserine; D017346:Protein Serine-Threonine Kinases; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D013110:Sphingosine; D014446:Tyrosine 3-Monooxygenase; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein; D020764:cdc42 GTP-Binding Protein; D054462:p21-Activated Kinases; D020741:rho GTP-Binding Proteins; C494820:Bad protein, mouse; C494812:Bcl2l1 protein, mouse; C064769:N-acetylsphingosine; C515905:Pak1 protein, mouse