Rapid activation of p38 mitogen-activated protein kinase by corticosterone in PC12 cells.
The present study using immunoblot showed that corticosterone (B) could induce a rapid activation of p38 in PC12 cells. The dose   and time  response curves w ere bell  shaped with a maximal activation at 10-9 mol/L and 15 min respectively. The activation was not affected by steroid nuclear receptor antagonist RU38486. Bovine serum albumin coupled B (B-BSA) could induce phosphorylation of p38. Tyrosine kinase inhibitor genistein failed to block the phosphorylation, a fact suggesting that the tyrosine kinase activity is not involved in the pathway. On the other hand, phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, could mimic the actions of B, while G  6976, a PKC inhibitor, could completely abolish the phosphorylation induced by B. These results clearly demonstrate that B activates p38 MAPK readily via a putative membrane receptor through a PKC-dependent pathway.
Li
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XY
Department of Biological Science and Technology, Nanjing University, Nanjing 210093, China.
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D003345:Corticosterone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016716:PC12 Cells / Q000187:drug effects / Q000201:enzymology; D051381:Rats; D048051:p38 Mitogen-Activated Protein Kinases
D000893:Anti-Inflammatory Agents; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D003345:Corticosterone