Conserved Residues within the Putative S4-S5 Region Serve Distinct Functions among Thermosensitive Vanilloid Transient Receptor Potential (TRPV) Channels
Conserved Residues within the Putative S4-S5 Region Serve Distinct Functions among Thermosensitive Vanilloid Transient Receptor Potential (TRPV) Channels
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DOI：
10.1074/jbc.m110.145466
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发表时间：
2010-12-31
影响因子：
4.8
通讯作者：
Vlachova, Viktorie
中科院分区：
文献类型：
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作者：
Boukalova, Stepana;Marsakova, Lenka;Vlachova, Viktorie
香草素瞬时受体电位通道TRPV 1是一个四聚体六跨膜片段（S1-S6）通道，可以被各种促痛剂（例如辣椒素、质子、热或高度去极化电压）以及2-氨基乙氧联苯硼酸盐（2-APB）协同激活，2-APB是相关热门控香草素TRP通道TRPV 1、TRPV 2和TRPV 3的常见激活剂。在这些通道中，细胞内S4-S5区域中的保守带电残基已被提出构成与其他刺激协同作用以调节通道激活的电压传感器的一部分。这种门控事件的分子基础知之甚少。我们突变了TRPV 1的S4和S4-S5接头上所有沿着的带电残基，并鉴定了四个潜在的电压敏感残基（Arg（557）、Glu（570）、Asp（576）和Arg（579）），当特异性突变时，它们改变了通道在电压、辣椒素、热、2-APB和/或它们以不同方式相互作用方面的功能。非功能性电荷逆转突变R557 E和R579 E部分被电荷交换突变R557 E/E570 R和D576 R/R579 E拯救，表明静电相互作用有助于电压，温度和辣椒素依赖性激活机制之间的变构偶联。K571 E突变株TRPV 1除2-APB外，其他各方面均正常，提示赖氨酸（571）在化学敏感性中的特殊作用。令人惊讶的是，在TRPV 2或TRPV 3中的同源残基处的取代对温度和2-APB诱导的活性没有影响。因此，S4和S4-S5接头中的带电残基有助于TRPV 1中的电压感应，尽管它们具有高度保守的性质，但它们以不同的方式调节各种TRPV通道中的温度和化学门控。
The vanilloid transient receptor potential channel TRPV1 is a tetrameric six-transmembrane segment (S1-S6) channel that can be synergistically activated by various proalgesic agents such as capsaicin, protons, heat, or highly depolarizing voltages, and also by 2-aminoethoxydiphenyl borate (2-APB), a common activator of the related thermally gated vanilloid TRP channels TRPV1, TRPV2, and TRPV3. In these channels, the conserved charged residues in the intracellular S4-S5 region have been proposed to constitute part of a voltage sensor that acts in concert with other stimuli to regulate channel activation. The molecular basis of this gating event is poorly understood. We mutated charged residues all along the S4 and the S4-S5 linker of TRPV1 and identified four potential voltage-sensing residues (Arg(557), Glu(570), Asp(576), and Arg(579)) that, when specifically mutated, altered the functionality of the channel with respect to voltage, capsaicin, heat, 2-APB, and/or their interactions in different ways. The nonfunctional charge-reversing mutations R557E and R579E were partially rescued by the charge-swapping mutations R557E/E570R and D576R/R579E, indicating that electrostatic interactions contribute to allosteric coupling between the voltage-, temperature- and capsaicin-dependent activation mechanisms. The mutant K571E was normal in all aspects of TRPV1 activation except for 2-APB, revealing the specific role of Lys(571) in chemical sensitivity. Surprisingly, substitutions at homologous residues in TRPV2 or TRPV3 had no effect on temperature- and 2-APB-induced activity. Thus, the charged residues in S4 and the S4-S5 linker contribute to voltage sensing in TRPV1 and, despite their highly conserved nature, regulate the temperature and chemical gating in the various TRPV channels in different ways.