Cell surface receptors activate p21-activated kinase 1 via multiple Ras and PI3-kinase-dependent pathways.
p21-activated kinases (PAKs) were the first identified mammalian members of a growing family of Ste20-like serine-threonine protein kinases. In this study, we show that PAK1 can be stimulated by carbachol, lysophosphatidic acid (LPA), epidermal growth factor (EGF), and phorbol 12-myristate 13-acetate (PMA) by multiple independent and overlapping pathways. Dominant-negative Ras, Rac, and Cdc42 inhibited PAK1 activation by all of these agonists, while active Rac1 and Cdc42 were sufficient to maximally activate PAK1 in the absence of any treatment. Active Ras induced only a weak activation of PAK1 that could be potentiated by muscarinic receptor stimulation. Studies using inhibitors of the EGF receptor tyrosine kinase, phosphatidylinositol 3-kinase (PI3-kinase) and protein kinase C (PKC) revealed that all of the cell surface agonists could activate PAK1 through pathways independent of PKC, that EGF stimulated a PI3-kinase dependent pathway to stimulate PAK1, and that muscarinic receptor stimulation of PAK1 was predominantly mediated through this EGF-R-dependent mechanism. Activation of PAK1 by LPA was independent of PI3-kinase and the EGF receptor, but was inhibited by dominant-negative RhoA. These results identify multiple Ras-dependent pathways to activation of PAK1.
Department of Pharmacology, Wayne State University, 540 E. Canfield, Room 6326, Detroit, MI 48201, USA.
Raymond E
RE
Menard
Raymond R
RR
Mattingly
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D019556:COS Cells; D002217:Carbachol / Q000494:pharmacology; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000502:physiology; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007700:Kinetics; D008246:Lysophospholipids / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D051379:Mice; D008954:Models, Biological; D004676:Myelin Basic Protein / Q000378:metabolism; D041681:NIH 3T3 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000187:drug effects / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011799:Quinazolines; D043585:Receptor, Muscarinic M2 / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection; D020032:Tyrphostins / Q000494:pharmacology; D000077191:Wortmannin; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D054462:p21-Activated Kinases; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
D000730:Androstadienes; D002217:Carbachol; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D007211:Indoles; D008246:Lysophospholipids; D008301:Maleimides; D004676:Myelin Basic Protein; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D017346:Protein Serine-Threonine Kinases; D011799:Quinazolines; D043585:Receptor, Muscarinic M2; D011956:Receptors, Cell Surface; D013755:Tetradecanoylphorbol Acetate; D020032:Tyrphostins; D000077191:Wortmannin; D020764:cdc42 GTP-Binding Protein; D054462:p21-Activated Kinases; D020744:rac GTP-Binding Proteins; D018631:ras Proteins; D020741:rho GTP-Binding Proteins; C101044:RTKI cpd; C515903:PAK1 protein, human; C515905:Pak1 protein, mouse; C088060:bisindolylmaleimide; C032881:lysophosphatidic acid