Functional role of C-terminal cytoplasmic tail of rat vanilloid receptor 1
Functional role of C-terminal cytoplasmic tail of rat vanilloid receptor 1
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DOI：
10.1523/jneurosci.23-04-01340.2003
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发表时间：
2003-02-15
影响因子：
5.3
通讯作者：
Vyklicky, L
中科院分区：
文献类型：
--
作者：
Vlachová, V;Teisinger, J;Vyklicky, L
香草酸受体[瞬时受体电位（TRP）V1，也称为VR1]是TRP通道家族的成员。这些受体具有显着的序列同源性，具有相似的预测结构，具有六个跨膜结构域 (S1-S6)、S5 和 S6 之间的孔形成区域以及细胞质定向的 C 端和 N 端区域。尽管结构/功能研究已经确定了一些影响 TRPV1 离子通道门控的关键氨基酸，但末端区域对香草酸受体功能的可能贡献仍然难以捉摸。在本研究中，构建了大鼠 TRPV1 的 C 末端截短，以表征细胞质 C 末端区域对 TRPV1 功能的贡献，并描绘形成功能通道所需的 C 尾的最小量。 31 个残基的截短足以诱导 TRPV1 通道功能特性的变化。在缺乏最后 72 个氨基酸的突变体中观察到 C 末端截断的更明显的影响。这些变化的特点是辣椒素、pH 值和热敏感性的下降；逐渐降低激活热阈值（从 41.5 到 28.6 摄氏度）；热诱发膜电流的激活速率减慢（Q（10）从25.6到4.7）。截短突变体的电压感应电流表现出较慢的起始速度、显着减少的向外整流以及显着较小的峰值尾电流幅度。整个 TRPV1 C 端结构域（155 个残基）的截断导致通道无功能。这些结果表明细胞质 COOH 末端结构域强烈影响 TRPV1 通道活性，并且该结构域的远端一半赋予特定的热敏感性。
The vanilloid receptor [transient receptor potential (TRP) V1, also known as VR1] is a member of the TRP channel family. These receptors share a significant sequence homology, a similar predicted structure with six transmembrane-spanning domains (S1-S6), a pore-forming region between S5 and S6, and the cytoplasmically oriented C- and N-terminal regions. Although structural/functional studies have identified some of the key amino acids influencing the gating of the TRPV1 ion channel, the possible contributions of terminal regions to vanilloid receptor function remain elusive. In the present study, C- terminal truncations of rat TRPV1 have been constructed to characterize the contribution of the cytoplasmic C- terminal region to TRPV1 function and to delineate the minimum amount of C tail necessary to form a functional channel. The truncation of 31 residues was sufficient to induce changes in functional properties of TRPV1 channel. More pronounced effects of C- terminal truncation were seen in mutants lacking the final 72 aa. These changes were characterized by a decline of capsaicin-, pH-, and heat-sensitivity; progressive reduction of the activation thermal threshold (from 41.5 to 28.6degreesC); and slowing of the activation rate of heat-evoked membrane currents (Q(10) from 25.6 to 4.7). The voltage-induced currents of the truncated mutants exhibited a slower onset, markedly reduced outward rectification, and significantly smaller peak tail current amplitudes. Truncation of the entire TRPV1 C- terminal domain (155 residues) resulted in a nonfunctional channel. These results indicate that the cytoplasmic COOH-terminal domain strongly influences the TRPV1 channel activity, and that the distal half of this structural domain confers specific thermal sensitivity.