A selective Ca2+calmodulin-dependent protein kinase II inhibitor, KN-62, inhibits the enhanced phosphorylation and the activation of tyrosine hydroxylase by 56 mM K+ in rat pheochromocytoma PC12h cells
Review articleOpen access
Akira Ishii - No affiliation found
1991/05/15 Full-length article DOI: 10.1016/0006-291X(91)90389-O
Journal: Biochemical and Biophysical Research Communications
AbstractInvolvement of Ca2+calmodulin-dependent protein kinase II (Ca2+CaM-kinase II) on the phosphorylation of tyrosine hydroxylase (TH, EC.18.104.22.168) in rat pheochromocytoma, PC12h cells was examined using KN-62, 1-[N,O-Bis(5-isoquinolinsulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine, a selective inhibitor of Ca2+CaM-kinase II. Both the enhanced phosphorylation of TH and the activated l-3,4-dihydroxyphenylalanine (DOPA) formation in the high K+ depolarization were inhibited by 10 μM KN-62. After incubation of PC12h cells with 10 μM KN-62 for 1 hr, the activation of TH with 3 min incubation of 56 mM K+ was reduced to the basal activity. However, KN-62 did not directly affect the activity of purified rat TH at pH 6.0 or 7.0. These results indicate that Ca2+CaM-kinase II phosphorylates and activates TH of PC12h cells in the high K+ depolarization.
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