Phosphorylation of vanilloid receptor 1 by Ca2+/calmodulin-dependent kinase II regulates its vanilloid binding
Phosphorylation of vanilloid receptor 1 by Ca2+/calmodulin-dependent kinase II regulates its vanilloid binding
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DOI：
10.1074/jbc.m311448200
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发表时间：
2004-02-20
影响因子：
4.8
通讯作者：
Oh, U
中科院分区：
文献类型：
--
作者：
Jung, JY;Shin, JS;Oh, U
香草酸受体 1 (VR1) 是一种辣椒素受体，已知在介导炎症热伤害感受中发挥重要作用。尽管VR1的生理作用和生物物理特性是已知的，但其被配体激活的机制却知之甚少。在这里，我们证明 VR1 在被辣椒素激活之前必须被 Ca2+-钙调蛋白依赖性激酶 II (CaMKII) 磷酸化。相反，钙调神经磷酸酶对 VR1 的去磷酸化会导致受体脱敏。此外，VR1 在 CaMKII 两个假定共有位点的点突变未能引发辣椒素敏感电流，并导致体内 VR1 磷酸化随之减少。这些突变体还失去了与[H-3]树脂毒素（一种有效的辣椒素受体激动剂）的高亲和力结合。我们得出结论，CaMKII 和钙调磷酸酶分别对 VR1 通道的磷酸化和去磷酸化之间的动态平衡通过调节 VR1 结合来控制激活/脱敏状态。此外，由于蛋白激酶 A 和 C 的致敏作用集中在这些位点，因此细胞中的磷酸化应激似乎控制着广泛的兴奋性，以响应各种不利刺激。
Vanilloid receptor 1 (VR1), a capsaicin receptor, is known to play a major role in mediating inflammatory thermal nociception. Although the physiological role and biophysical properties of VR1 are known, the mechanism of its activation by ligands is poorly understood. Here we show that VR1 must be phosphorylated by Ca2+-calmodulin dependent kinase II (CaMKII) before its activation by capsaicin. In contrast, the dephosphorylation of VR1 by calcineurin leads to a desensitization of the receptor. Moreover, point mutations in VR1 at two putative consensus sites for CaMKII failed to elicit capsaicin-sensitive currents and caused a concomitant reduction in VR1 phosphorylation in vivo. Such mutants also lost their high affinity binding with [H-3]resiniferatoxin, a potent capsaicin receptor agonist. We conclude that the dynamic balance between the phosphorylation and dephosphorylation of the VR1 channel by CaMKII and calcineurin, respectively, controls the activation/ desensitization states by regulating VR1 binding. Furthermore, because sensitization by protein kinase A and C converge at these sites, phosphorylation stress in the cell appears to control a wide range of excitabilities in response to various adverse stimuli.