title: Activation of p21-activated kinase 1 is required for lysophosphatidic acid-induced focal adhesion kinase phosphorylation and cell motility in human melanoma A2058 cells.
abstract: Lysophosphatidic acid (LPA), one of the naturally occurring phospholipids, stimulates cell motility through the activation of Rho family members, but the signaling mechanisms remain to be elucidated. In the present study, we investigated the roles of p21-activated kinase 1 (PAK1) on LPA-induced focal adhesion kinase (FAK) phosphorylation and cell motility. Treatment of human melanoma cells A2058 with LPA increased phosphorylation and activation of PAK1, which was blocked by treatment with pertussis toxin and by inhibition of phosphoinositide 3-kinase (PI3K) with an inhibitor LY294002 or by overexpression of catalytically inactive mutant of PI3Kgamma, indicating that LPA-induced PAK1 activation was mediated via a Gi protein and the PI3Kgamma signaling pathway. In addition, we demonstrated that Rac1/Cdc42 signals acted as upstream effector molecules of LPA-induced PAK activation. However, Rho-associated kinase, MAP kinase kinase 1/2 or phospholipase C might not be involved in LPA-induced PAK1 activation or cell motility stimulation. Furthermore, PAK1 was necessary for FAK phosphorylation by LPA, which might cause cell migration, as transfection of the kinase deficient mutant of PAK1 or PAK auto-inhibitory domain significantly abrogated LPA-induced FAK phosphorylation. Taken together, these findings strongly indicated that PAK1 activation was necessary for LPA-induced cell motility and FAK phosphorylation that might be mediated by sequential activation of Gi protein, PI3Kgamma and Rac1/Cdc42.
authors.affiliation: College of Medicine, Konyang University, Nonsan 320-711, Korea.
authors.forename: In Duk
authors.initials: ID
authors.lastname: Jung
authors.forename: Jangsoon
authors.initials: J
authors.lastname: Lee
authors.forename: Kyung Bok
authors.initials: KB
authors.lastname: Lee
authors.forename: Chang Gyo
authors.initials: CG
authors.lastname: Park
authors.forename: Yong Kee
authors.initials: YK
authors.lastname: Kim
authors.forename: Dong Wan
authors.initials: DW
authors.lastname: Seo
authors.forename: Dongeun
authors.initials: D
authors.lastname: Park
authors.forename: Hyang Woo
authors.initials: HW
authors.lastname: Lee
authors.forename: Jeung-Whan
authors.initials: JW
authors.lastname: Han
authors.forename: Hoi Young
authors.initials: HY
authors.lastname: Lee
mesh_terms: D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D058544:Class Ib Phosphatidylinositol 3-Kinase; D004789:Enzyme Activation / Q000187:drug effects; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D022001:Focal Adhesions; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D008246:Lysophospholipids / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008545:Melanoma / Q000201:enzymology* / Q000235:genetics / Q000473:pathology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D015398:Signal Transduction; D014162:Transfection; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D054462:p21-Activated Kinases; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: D058544:Class Ib Phosphatidylinositol 3-Kinase; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D007527:Isoenzymes; D008246:Lysophospholipids; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D020764:cdc42 GTP-Binding Protein; D054462:p21-Activated Kinases; D020830:rac1 GTP-Binding Protein; C113183:FAK-related nonkinase; C546760:PIK3CG protein, human; C496050:PTK2 protein, human; C515903:PAK1 protein, human