The stimulation of MAP kinase by 1,25(OH)(2)-vitamin D(3) in skeletal muscle cells is mediated by protein kinase C and calcium.
In previous work we have demonstrated that the steroid hormone 1,25(OH)(2)-vitamin D(3) [1,25(OH)(2)D(3)] stimulates in skeletal muscle cells the phosphorylation and activity of the extracellular signal-regulated mitogen-activated protein (MAP) kinase isoforms ERK1 and ERK2. In the present study we evaluated the involvement of Ca(2+) and protein kinase C (PKC) on 1,25(OH)(2)D(3)-induced activation of MAP kinase. The hormone response was found to depend on PKC stimulation since it was attenuated by the PKC inhibitors calphostin C (100 nM) and bisindolylmaleimide I (30 nM) and PKC downregulation by prolonged treatment with the phorbol ester TPA (1 microM). Removal of external Ca(2+), chelation of intracellular Ca(2+) with BAPTA (5 microM), inhibition of phosphoinositide-phospholipase C (PLC) by neomycin, the calmodulin antagonist fluphenazine (50 microM) and the specific inhibitor of calmodulin kinase II, KN-62 (10 microM), significantly decreased 1,25(OH)(2)D(3)-activation of MAP kinase. In addition, the Ca(2+)-channel blocker verapamil (5 microM) suppressed hormone-induced MAP kinase activity in these cells. Furthermore, the Ca(2+)-mobilizing agent thapsigargin and the Ca(2+)-inophore A23187 paralleled the phosphorylation of MAP kinase observed with 1,25(OH)(2)D(3). Taken together, these results indicate that PKC and Ca(2+) are two upstream activators mediating the effects of 1,25(OH)(2)D(3) on MAP kinase in skeletal muscle cells.
Departamento de Biologia, Bioquímica and Farmacia, Universidad Nacional del Sur, San Juan 670, 8000, Bahia Blanca, Argentina.
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Morelli
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Buitrago
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Boland
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de Boland
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002117:Calcitriol / Q000494:pharmacology*; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002147:Calmodulin / Q000037:antagonists & inhibitors; D002642:Chick Embryo; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005476:Fluphenazine / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008301:Maleimides / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D009281:Naphthalenes / Q000494:pharmacology; D009355:Neomycin / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism; D014700:Verapamil / Q000494:pharmacology
D002147:Calmodulin; D007211:Indoles; D008301:Maleimides; D009281:Naphthalenes; D000001:Calcimycin; D004533:Egtazic Acid; C063302:KN 62; D019284:Thapsigargin; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D014700:Verapamil; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D010738:Type C Phospholipases; D002117:Calcitriol; D009355:Neomycin; C058819:calphostin C; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; C070515:bisindolylmaleimide I; D013755:Tetradecanoylphorbol Acetate; D005476:Fluphenazine; D002118:Calcium