The blue-light receptor YtvA acts in the environmental stress signaling pathway of Bacillus subtilis
The blue-light receptor YtvA acts in the environmental stress signaling pathway of Bacillus subtilis
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DOI：
10.1128/jb.00691-06
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发表时间：
2006-09-01
影响因子：
3.2
通讯作者：
Price, Chester W.
中科院分区：
文献类型：
--
作者：
Gaidenko, Tatiana A.;Kim, Tae-Jong;Price, Chester W.
枯草芽孢杆菌的一般应激反应受伴侣转换机制调节，其中丝氨酸和苏氨酸磷酸化控制应激信号通路中的蛋白质相互作用。该途径的环境分支包含一个由五种旁系同源蛋白组成的家族，其功能为负调节因子。在这里，我们提出的遗传证据表明，第六个parasites，YtvA，作为一个积极的调节器在同一个环境信号分支。我们还提出了生化证据表明，YtvA和至少三个负调节器可以从细胞提取物中分离出一个大的环境信号复合体。YtvA与这些相关的负调节因子的不同之处在于其含有黄素单核苷酸（FMN）的光氧电压结构域。其他人已经表明，该结构域具有预期的蓝光传感器的光化学，其中FMN发色团与半胱氨酸62的共价连接构成光循环的关键部分。与光强度改变环境信号传导途径的输出的观点一致，我们发现半胱氨酸62是YtvA在没有其他压力的情况下发挥其积极的调节作用所必需的。ytvA结构基因的转录分析表明，它提供了至少一个额外的环境输入的切入点，介导的Spx全球调节二硫化物应力。这些结果支持了一个模型，其中大的信号复合体用于整合多种环境信号，以调节一般的应激反应。
The general stress response of the bacterium Bacillus subtilis is regulated by a partner-switching mechanism in which serine and threonine phosphorylation controls protein interactions in the stress-signaling pathway. The environmental branch of this pathway contains a family of five paralogous proteins that function as negative regulators. Here we present genetic evidence that a sixth paralog, YtvA, acts as a positive regulator in the same environmental signaling branch. We also present biochemical evidence that YtvA and at least three of the negative regulators can be isolated from cell extracts in a large environmental signaling complex. YtvA differs from these associated negative regulators by its flavin mononucleotide (FMN)-containing light-oxygen-voltage domain. Others have shown that this domain has the photochemistry expected for a blue-light sensor, with the covalent linkage of the FMN chromophore to cysteine 62 composing a critical part of the photocycle. Consistent with the view that light intensity modifies the output of the environmental signaling pathway, we found that cysteine 62 is required for YtvA to exert its positive regulatory role in the absence of other stress. Transcriptional analysis of the ytvA structural gene indicated that it provides the entry point for at least one additional environmental input, mediated by the Spx global regulator of disulfide stress. These results support a model in which the large signaling complex serves to integrate multiple environmental signals in order to modulate the general stress response.