Stabilization of polar localization of a chemoreceptor via its covalent modifications and its communication with a different chemoreceptor
Stabilization of polar localization of a chemoreceptor via its covalent modifications and its communication with a different chemoreceptor
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DOI：
10.1128/jb.187.22.7647-7654.2005
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发表时间：
2005-11-01
影响因子：
3.2
通讯作者：
Kawagishi, I
中科院分区：
文献类型：
--
作者：
Shiomi, D;Banno, S;Kawagishi, I
在大肠杆菌的趋化性中，趋化受体、组氨酸激酶CheA和接头蛋白CheW的极性聚类被认为参与了信号放大和适应。然而，导致受体极性定位的机制在很大程度上仍然未知。在这项研究中，我们研究了受体共价修饰对天冬氨酸化学受体Tar与绿色荧光蛋白（GFP）融合的极性定位的影响。Tar-GFP的酰胺化（可能是甲基化）增强了其自身的极性定位，尽管影响很小。酰胺化对受体定位的轻微但显著的影响被以下事实所加强：靶向Tar的c端五肽序列的GFP-CheR的非催化突变版本的定位同样被受体酰胺化促进。去甲基化版本的Tar-GFP的极性定位也通过增加丝氨酸化学受体Tsr的水平而增强。共价修饰本身对受体定位的影响可能太小，不足以解释趋化适应，但受体修饰被认为有助于细胞极点上化学受体/组氨酸激酶阵列的分子组装，可能是通过稳定受体二聚体对二聚体的相互作用。
In the chemotaxis of Escherichia coli, polar clustering of the chemoreceptors, the histidine kinase CheA, and the adaptor protein CheW is thought to be involved in signal amplification and adaptation. However, the mechanism that leads to the polar localization of the receptor is still largely unknown. In this study, we examined the effect of receptor covalent modification on the polar localization of the aspartate chemoreceptor Tar fused to green fluorescent protein (GFP). Amidation (and presumably methylation) of Tar-GFP enhanced its own polar localization, although the effect was small. The slight but significant effect of amidation on receptor localization was reinforced by the fact that localization of a noncatalytic mutant version of GFP-CheR that targets to the C-terminal pentapeptide sequence of Tar was similarly facilitated by receptor amidation. Polar localization of the demethylated version of Tar-GFP was also enhanced by increasing levels of the serine chemoreceptor Tsr. The effect of covalent modification on receptor localization by itself may be too small to account for chemotactic adaptation, but receptor modification is suggested to contribute to the molecular assembly of the chemoreceptor/histidine kinase array at a cell pole, presumably by stabilizing the receptor dimer-to-dimer interaction.