Distinct regulation of expressed calcium channels 2.3 in Xenopus oocytes by direct or indirect activation of protein kinase C.
Distinct regulation of expressed calcium channels 2.3 in Xenopus oocytes by direct or indirect activation of protein kinase C.
复制标题
通过直接或间接激活蛋白激酶 C 对非洲爪蟾卵母细胞中表达的钙通道 2.3 进行明显调节。
DOI：
10.1016/s0006-8993(03)02245-5
复制
发表时间：
2003
期刊：
影响因子：
2.9
通讯作者：
Lynch3rd,Carl
中科院分区：
文献类型：
--
作者：
Kamatchi,GanesanL;Tiwari,ShvetaN;Chan,CarrieK;Chen,Daguang;Do,Sang-Hwan;Durieux,MarcelE;Lynch3rd,Carl
使用佛波醇 12-肉豆蔻酸酯 13-乙酸酯 (PMA) 或通过爪蟾卵母细胞中的 M1 毒蕈碱受体激活，研究了电压门控 Ca（Cav；具有 α1β1Bα2/δ 亚基）通道 2.3 的蛋白激酶 C (PKC) 依赖性调节。以 Ba2+(IBa) 作为电荷载体的内向 Ca2+ 电流被 PMA 或乙酰基-β-甲基胆碱 (MCh) 增强。 MCh或PMA均增加了IBa的失活[I(inact)]和非失活[I(noninact)]成分以及失活时间常数τ(inact)。这可能是 PKC 依赖性作用，因为 MCh 和 PMA 的作用被 Ro-31-8425 或 β-伪底物阻断。 MCh 效应可被阿托品、鸟苷-5'-O-(2-硫代二磷酸)三锂 (GDPβS) 或 U-73122 阻断。分别通过抑制肌醇-1,4,5-三磷酸 (IP3) 受体、细胞内 Ca2+([Ca2+]i) 或肝素、BAPTA 和 βC2.4 的常规 PKC (cPKC) 易位来阻断 MCh 而不是 PMA 的作用。虽然较低浓度 (25 nM) 的 Ro-31-8425 会阻断 MCh，但需要较高浓度 (500 nM) 的 Ro-31-8425 才能阻断 PMA 作用。 MCh 和 PMA 对肝素、BAPTA、βC2.4 或 Ro-31-8425 的这种不同敏感性表明 Ca2+ 依赖性 cPKC 参与 MCh 作用，而 cPKC 和 Ca2+ 独立的新型 PKC (nPKC) 参与 PMA 作用。 PMA 导致 IBa 进一步增加，而预施用的 MCh（1 或 10 μM）已经增强了 IBa，这表明 cPKC 和 nPKC 的差异磷酸化位点可能存在于 Cav2.3 通道的 α12.3 亚基中。
Protein kinase C (PKC)-dependent regulation of voltage-gated Ca (Cav; with α1β1Bα2/δ subunits) channel 2.3 was investigated using phorbol 12-myristate 13-acetate (PMA), or by M1muscarinic receptor activation in Xenopus oocytes. The inward Ca2+-current with Ba2+(IBa) as the charge carrier was potentiated by PMA or acetyl-β-methylcholine (MCh). The inactivating [I(inact)] and non-inactivating [I(noninact)] components of IBaand the time constant of inactivation τ(inact)were all increased by MCh or PMA. This may be a PKC-dependent action since the effect of MCh and PMA was blocked by Ro-31-8425 or β-pseudosubstrate. MCh effect was blocked by atropine, guanosine-5′-O-(2-thiodiphosphate) trilithium (GDPβS) or U-73122. The effect of MCh but not PMA was blocked by the inhibition of inositol-1,4,5-trisphosphate (IP3) receptors, intracellular Ca2+([Ca2+]i) or the translocation of conventional PKC (cPKC) with heparin, BAPTA and βC2.4, respectively. While a lower concentration (25 nM) of Ro-31-8425 blocked MCh, a higher concentration (500 nM) of Ro-31-8425 was required to block PMA action. This differential susceptibility of MCh and PMA to heparin, BAPTA, βC2.4 or Ro-31-8425 is suggestive of the involvement of Ca2+-dependent cPKC in MCh action, whereas cPKC and Ca2+-independent novel PKC (nPKC) in PMA action. PMA led to additional increase in IBathat was already potentiated by preadministered MCh (1 or 10 μM), leading to the suggestion that differential phosphorylation sites for cPKC and nPKC may be present in the α12.3 subunit of Cav2.3 channels.