Essential role for the putative S6 inner pore region in the activation gating of the human TRPA1 channel
Essential role for the putative S6 inner pore region in the activation gating of the human TRPA1 channel
复制标题
DOI：
10.1016/j.bbamcr.2009.04.014
复制
发表时间：
2009-07-01
影响因子：
5.1
通讯作者：
Vlachova, Viktorie
中科院分区：
文献类型：
--
作者：
Benedikt, Jan;Samad, Abdul;Vlachova, Viktorie
锚蛋白瞬时受体电位通道TRPA 1是一种感觉神经元特异性通道，其由各种促痛觉剂如异硫氰酸烯丙酯（AITC）、深度冷却或高度去极化电压门控。这些不同的刺激如何汇聚在通道蛋白上以打开/关闭其离子传导孔是未知的。我们在人TRPA 1的S6内孔形成区域内鉴定了几个有助于AITC和电压依赖性门控的残基。保守的中间-S6脯氨酸（P949 A）中的丙氨酸取代强烈影响激活/失活和离子渗透。P949 A通过用甘氨酸取代而不是通过在位置-1、-2或+1引入脯氨酸而在功能上恢复，这表明P949在结构上是TRPA 1通道正常功能所需的。突变N954 A产生了组成型开放表型，表明在稳定封闭构象的作用。丙氨酸取代在远端GXXXG基序降低了Ca 2+的通道的相对渗透性，并强烈影响其激活/失活特性，表明远端G962稳定开放构象。另一方面，G958提供额外的调谐，导致信道活动减少。总之，这些研究结果提供了功能支持的关键作用，推定的内孔区域在控制的构象变化，确定TRPA 1通道的开放和关闭状态之间的转换。(C)2009 Elsevier B. V.保留所有权利。
The ankyrin transient receptor potential channel TRPA1 is a sensory neuron-specific channel that is gated by various proalgesic agents such as allyl isothiocyanate (AITC), deep cooling or highly depolarizing voltages. How these disparate stimuli converge on the channel protein to open/close its ion-conducting pore is unknown. We identify several residues within the S6 inner pore-forming region of human TRPA1 that contribute to AITC and voltage-dependent gating. Alanine substitution in the conserved mid-S6 proline (P949A) strongly affected the activation/deactivation and ion permeation. The P949A was functionally restored by substitution with a glycine but not by the introduction of a proline at positions - 1, - 2 or + 1, which indicates that P949 is structurally required for the normal functioning of the TRPA1 channel. Mutation N954A generated a constitutively open phenotype, suggesting a role in stabilizing the closed conformation. Alanine substitutions in the distal GXXXG motif decreased the relative permeability of the channel for Ca2+ and strongly affected its activation/deactivation properties, indicating that the distal G962 stabilizes the open conformation. G958, on the other hand, provides additional tuning leading to decreased channel activity. Together these findings provide functional support for the critical role of the putative inner pore region in controlling the conformational changes that determine the transitions between the open and close states of the TRPA1 channel. (C) 2009 Elsevier B.V. All rights reserved.