蛋白激酶C介导的成年大鼠脑中Kvβ2的磷酸化作用
Protein kinase C-mediated phosphorylation of Kv beta 2 in adult rat brain.
作者信息
Wang Xintao, Zhang Jie, Berkowski Stan M, Knowleg Heather, Chandramouly A B, Downens Martha, Prystowsky Michael B
机构信息
Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
出版信息
Neurochem Res. 2004 Oct;29(10):1879-86. 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.
通过不同的蛋白激酶对Kvbeta2的磷酸化作用进行了研究。蛋白激酶A催化亚基（PKA-CS）使重组Kvbeta2（rKvbeta2）发生的磷酸化作用最强，蛋白激酶C催化亚基（PKC-CS）导致的磷酸化作用有限，而酪蛋白激酶II（CKII）未检测到磷酸化作用。成年大鼠脑匀浆中的蛋白激酶使rKvbeta2和内源性Kvbeta均发生了磷酸化。PKA抑制剂PKI 6-22完全抑制了PKA介导的rKvbeta2磷酸化作用，但对大鼠脑中存在的激酶活性的抑制作用最小。阻断PKCalpha、PKCbeta、PKCgamma、PKCdelta和PKCzeta活性的抑制剂Gö 6983抑制了大鼠脑激酶对rKvbeta2的磷酸化作用，而阻断PKCalpha和PKCbetaI活性的Gö 6976则无抑制作用。Gö 6983抑制活性的剂量反应分析表明，大鼠脑中存在的激酶活性至少由两种PKC同工酶引起。因此，虽然PKA是体外对rKvbeta2进行磷酸化作用最活跃的蛋白激酶，但大鼠脑中Kvbeta2的磷酸化主要由PKC同工酶介导。
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