title: Roles of Rac and p38 kinase in the activation of cytosolic phospholipase A2 in response to PMA.
abstract: The roles of Rac and p38 kinase in the activation of cPLA2 (cytosolic PLA2) in Rat-2 fibroblasts were investigated. In the present study, we found that PMA activates cPLA2 by a Rac-p38 kinase-dependent pathway. Consistent with this, Rac, if activated, was shown to stimulate cPLA2 in a p38 kinase-dependent manner. In another experiment to understand the signalling mechanism by which the Rac-p38 kinase cascade mediates cPLA2 activation in response to PMA, we observed that PMA-induced cPLA2 translocation to the perinuclear region is completely inhibited by the expression of Rac1N17 or treatment with SB203580 (inhibitor of p38 kinase), suggesting that Rac-p38 kinase cascade acts in this instance by mediating the translocation of cPLA2. The mediatory role of p38 kinase in cPLA2 activation was further demonstrated after a treatment with anisomycin, a very effective activator of p38 kinase. Consistent with the mediatory role of p38 kinase in stimulating cPLA2, anisomycin induced the translocation and activation of cPLA2 in a p38 kinase-dependent manner.
authors.affiliation: Department of Life Science, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: You
authors.forename: Chang-Hoon
authors.initials: CH
authors.lastname: Woo
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Choi
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Cho
authors.forename: Yung Joon
authors.initials: YJ
authors.lastname: Yoo
authors.forename: Jae-Hong
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000818:Animals; D000841:Anisomycin / Q000494:pharmacology; D002460:Cell Line; D003600:Cytosol / Q000201:enzymology; D004789:Enzyme Activation; D005347:Fibroblasts / Q000201:enzymology; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D021381:Protein Transport; D051381:Rats; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*; D020744:rac GTP-Binding Proteins / Q000378:metabolism*
chemical_list: D000841:Anisomycin; D048051:p38 Mitogen-Activated Protein Kinases; D010741:Phospholipases A; D054467:Phospholipases A2; D020744:rac GTP-Binding Proteins; D013755:Tetradecanoylphorbol Acetate