Effects of isoflurane on the expressed Cav2.2 currents in Xenopus oocytes depend on the activation of protein kinase Cδ and its phosphorylation sites in the Cav2.2α1 subunits.
Effects of isoflurane on the expressed Cav2.2 currents in Xenopus oocytes depend on the activation of protein kinase Cδ and its phosphorylation sites in the Cav2.2α1 subunits.
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异氟烷对非洲爪蟾卵母细胞中表达的 Cav2.2 电流的影响取决于蛋白激酶 Cδ 的激活及其在 Cav2.2α1 亚基中的磷酸化位点。
DOI：
10.1016/j.neuroscience.2011.02.041
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发表时间：
2011
期刊：
影响因子：
3.3
通讯作者：
Kamatchi,GL
中科院分区：
文献类型：
--
作者：
Rajagopal,S;Fang,H;Lynch3rd,C;Sando,JJ;Kamatchi,GL
观察了异氟醚对蛋白激酶C同工酶βII、ε或δ及其联合作用对两种神经元电压门控性钙通道(Cav；Cav2.1和2.2.)的影响。将Cav2.1α1或Cav2.2α1与β1b和α2δ亚基一起在爪哇卵母细胞中表达，双电极电压钳记录电流(IBa)。异氟醚(0.70 mM)可使CAV2.1和CAV2.2电流降低20-35%，并使PKCδ移位到膜上。与野生型(WT)相比，在不存在刺激性PKC位点(Thr-422、Ser-1757、Ser-2108、Ser-2132)和存在抑制性PKC位点(Ser-425)的情况下，异氟醚对Cav2.2电流的抑制作用更强。相反，与WT相比，异氟醚对表达抑制位突变体S425A的卵母细胞的抑制作用较小。PKCδ本身不调制Cav2.2电流，但在异氟烷存在时增强这些电流。PKCε单独或与异氟醚合用均可增加Cav2.2电流。蛋白激酶C激活剂佛波醇-12-肉豆蔻酸酯、13-乙酸酯和乙酰甲基胆碱对CAV2.1电流无调制作用。(2)佛波醇-12-肉豆蔻酸酯、13-乙酸酯和乙酰甲基胆碱(β-Mch)对Cav2.1电流无明显影响。然而，异氟醚的存在使PMA(而不是MCH)增强Cav2.1电流。PMA激活的PKCβII和PKCε同工酶不改变CAV2.1电流。然而，在异氟醚存在的情况下，这两种同工酶共同增强了Cav2.1电流。在异氟烷存在下，CAV2.1电流对PKCβII和PKCε和CAV2.2电流对PKCδ的不同响应可能是由于这些同工酶对其α1亚基的丝氨酸/苏氨酸PKC位点的亲和力或可及性增加所致。
The effects of isoflurane on the modulation of two neuronal voltage-gated calcium channels (Cav; Cav2.1 and 2.2) by protein kinase C (PKC) isozymes βII, ε or δ and their combination were examined. Cav2.1α1 or Cav2.2α1 with β1b and α2δ subunits were expressed inXenopusoocytes and the currents (IBa) were recorded by two-electrode voltage clamp. Isoflurane (0.70 mM) decreased both Cav2.1 and 2.2 currents by 20–35% and also caused translocation of PKCδ to the membrane. Compared to the wild type (WT), isoflurane caused greater inhibition of Cav2.2 currents in the absence of stimulatory PKC sites (Thr-422, Ser-1757, Ser-2108, Ser-2132) and in the presence of inhibitory PKC site (Ser-425). In contrast, isoflurane caused less inhibition ofIBain the oocytes expressing S425A, the inhibitory site mutant, compared to WT. PKCδ by itself did not modulate Cav2.2 currents, but potentiated these currents in the presence of isoflurane. PKCε increased Cav2.2 currents either alone or in combination with isoflurane. Cav2.1 currents were not modulated by phorbol-12-myristate, 13-acetate (PMA) or acetyl-β-methylcholine (MCh), activators of PKC. Yet the presence of isoflurane caused PMA (but not MCh) to enhance Cav2.1 currents. PKCβII and PKCε isozymes activated by PMA, did not alter Cav2.1 currents. However, in the presence of isoflurane, these two isozymes together potentiated Cav2.1 currents. The variable responses of Cav2.1 currents to PKCβII and PKCε and Cav2.2 currents to PKCδ in the presence of isoflurane may be due to increased affinity or accessibility of these isozymes to their Ser/Thr PKC sites of Cavα1 subunits.