Regulation of lysophosphatidic acid-stimulated tyrosine phosphorylation of mitogen-activated protein kinase by protein kinase C- and pertussis toxin-dependent pathways in the endothelial cell line EAhy 926.
In the endothelial cell line EAhy 926, 1-oleoyl-lysophosphatidic acid (LPA) stimulated the tyrosine phosphorylation of the pp42 isoform of mitogen-activated protein (MAP) kinase. Maximum phosphorylation was observed within 5 min of LPA addition, but the response was sustained for up to 120 min. Re-addition of LPA after 60 min stimulated a further sustained increase in the tyrosine phosphorylation of MAP kinase. In cells pretreated with phorbol 12-myristate 13-acetate (PMA; 24 h) or preincubated with the protein kinase C inhibitor Ro-318220, LPA-induced tyrosine phosphorylation of pp42 MAP kinase was substantially reduced at 2 min but potentiated at 60 min. Ro-318220 in combination with either PMA or pertussis toxin pretreatment abolished the LPA response at all time points, suggesting an involvement of protein kinase C in the pertussis toxin-sensitive part of the pathway. Agents which raised intracellular cyclic AMP levels did not affect the initial phase of LPA-stimulated MAP kinase activation, but abolished the late phase. However, this effect was prevented by Ro-318220, implicating a greater role for protein kinase C than protein kinase A in the regulation of sustained MAP kinase responses. LPA stimulated an increase in the tyrosine phosphorylation of focal adhesion kinase pp125 (pp125FAK) in EAhy 926 cells which was both protein kinase C- and pertussis toxin-independent. These results are discussed in terms of the pathways regulating both MAP kinase and pp125FAK in response to LPA in the EAhy 926 endothelial cells line.
McLees
A
A
Department of Physiology and Pharmacology, University of Strathclyde, Glasgow, U.K.
Graham
A
A
Malarkey
K
K
Gould
G W
GW
Plevin
R
R
D015815:Cell Adhesion Molecules / Q000378:metabolism; D002478:Cells, Cultured; D004727:Endothelium / Q000187:drug effects / Q000378:metabolism; D004789:Enzyme Activation; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D007700:Kinetics; D008246:Lysophospholipids / Q000494:pharmacology*; D019950:Mitogen-Activated Protein Kinase 1; D037342:Pertussis Toxin; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000187:drug effects / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism*; D011994:Recombinant Proteins / Q000187:drug effects / Q000378:metabolism; D012680:Sensitivity and Specificity; D013268:Stimulation, Chemical; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014443:Tyrosine / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D015815:Cell Adhesion Molecules; D008246:Lysophospholipids; D011994:Recombinant Proteins; D010566:Virulence Factors, Bordetella; D014443:Tyrosine; D037342:Pertussis Toxin; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D013755:Tetradecanoylphorbol Acetate; C032881:lysophosphatidic acid