Protein kinase C-mediated phosphorylation of Kv beta 2 in adult rat brain

• Published in: Neurochemical research 2004-10, Vol.29 (10), p.1879-1886
• Main Authors: Wang, Xintao, Zhang, Jie, Berkowski, Stan M, Knowleg, Heather, Chandramouly, A B, Downens, Martha, Prystowsky, Michael B
• Format: Article
• Language: English
• Subjects: Animals; Brain - drug effects; Brain - metabolism; Dose-Response Relationship, Drug; Enzyme Inhibitors - pharmacology; Phosphorylation - drug effects; Potassium Channels, Voltage-Gated - metabolism; Protein Kinase C - antagonists & inhibitors; Protein Kinase C - metabolism; Rats
• ISSN: 0364-3190
• DOI: 10.1023/B:NERE.0000042215.92952.3d

The phosphorylation of Kvbeta2 was investigated by different protein kinases. Protein kinase A catalytic subunit (PKA-CS) yielded the greatest phosphorylation of recombinant Kvbeta2 (rKvbeta2), with limited phosphorylation by protein kinase C catalytic subunit (PKC-CS) and no detectable phosphorylation by casein kinase II (CKII). Protein kinase(s) from adult rat brain lysate phosphorylated both rKvbeta2 and endogenous Kvbeta. The PKA inhibitor, PKI 6-22, fully inhibited PKA-mediated phophorylation of rKvbeta2 yet showed minimal inhibition of kinase activity present in rat brain. The inhibitor Gö 6983, that blocks PKCalpha, PKCbeta, PKCgamma, PKCdelta and PKCzeta activities, inhibited rKvbeta2 phosphorylation by rat brain kinases, with no inhibition by Gö 6976 which blocks PKCalpha and PKCbetaI activities. Dose-response analysis of Gö 6983 inhibitory activity indicates that at least two PKC isozymes account for the kinase activity present in rat brain. Thus, while PKA was the most active protein kinase to phosphorylate rKvbeta2 in vitro, Kvbeta2 phosphorylation in the rat brain is mainly mediated by PKC isozymes.