Yeast gain-of-function mutations reveal structure-function relationships conserved among different subfamilies of transient receptor potential channels.
Yeast gain-of-function mutations reveal structure-function relationships conserved among different subfamilies of transient receptor potential channels.
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酵母功能获得突变揭示了瞬时受体电位通道不同亚家族之间保守的结构-功能关系。
DOI：
10.1073/pnas.0708584104
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发表时间：
2007
影响因子：
11.1
通讯作者：
Kung,Ching
中科院分区：
文献类型：
--
作者：
Su,Zhenwei;Zhou,Xinliang;Haynes,WJohn;Loukin,StephenH;Anishkin,Andriy;Saimi,Yoshiro;Kung,Ching
在动物、原生生物和真菌中发现的瞬时受体电位（TRP）通道是主要的化学、热或机械传感器。目前的研究强调每个动物TRP亚家族中单个通道的特征，而不是跨亚家族的共同机制。酵母TRP通道TrpY1的正向遗传筛选在体内和体外恢复了具有表型的功能获得性（GOF）突变。这些GOF突变通道的单通道膜片钳分析显示开放概率和通道动力学的显着畸变。这些突变揭示了功能上重要的芳香族氨基酸残基在四个位置：在细胞内端的第五跨膜螺旋（TM5），在两端的TM6，并在立即延伸的TM6。这些芳烃在大多数TRP亚族中具有对应物。TM5中的一个（F380 L）与一个异常的果蝇突变等位基因（F550 I）精确对齐，该等位基因引起典型TRP通道的组成性活性，导致快速和严重的视网膜变性，而不仅仅是失去趋光性。因此，这种苯丙氨酸维持昆虫光转导通道以及真菌机械转导通道的各种功能状态（构象）的平衡。该残基是在所有已知的TRP通道亚家族中发现的一小簇苯丙氨酸中的一种。这种独特的情况下，说明GOF突变可以揭示结构功能的原则，可以推广到不同的TRP亚家族。看来，保守的芳香族化合物在四个位置中具有保守的功能，在大多数TRP通道。这些芳香族化合物的可能的机械作用和进一步使用酵母遗传学解剖TRP通道进行了讨论。
Transient receptor potential (TRP) channels found in animals, protists, and fungi are primary chemo-, thermo-, or mechanosensors. Current research emphasizes the characteristics of individual channels in each animal TRP subfamily but not the mechanisms common across subfamilies. A forward genetic screen of the TrpY1, the yeast TRP channel, recovered gain-of-function (GOF) mutations with phenotypein vivoandin vitro. Single-channel patch-clamp analyses of these GOF-mutant channels show prominent aberrations in open probability and channel kinetics. These mutations revealed functionally important aromatic amino acid residues in four locations: at the intracellular end of the fifth transmembrane helix (TM5), at both ends of TM6, and at the immediate extension of TM6. These aromatics have counterparts in most TRP subfamilies. The one in TM5 (F380L) aligns precisely with an exceptionalDrosophilamutant allele (F550I) that causes constitutive activity in the canonical TRP channel, resulting in rapid and severe retinal degeneration beyond mere loss of phototaxis. Thus, this phenylalanine maintains the balance of various functional states (conformations) of a channel for insect phototransduction as well as one for fungal mechanotransduction. This residue is among a small cluster of phenylalanines found in all known subfamilies of TRP channels. This unique case illustrates that GOF mutations can reveal structure–function principles that can be generalized across different TRP subfamilies. It appears that the conserved aromatics in the four locations have conserved functions in most TRP channels. The possible mechanistic roles of these aromatics and the further use of yeast genetics to dissect TRP channels are discussed.