The degradation of RcsA by ClpYQ(HslUV) protease in Escherichia coli
The degradation of RcsA by ClpYQ(HslUV) protease in Escherichia coli
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DOI：
10.1016/j.micres.2016.01.001
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发表时间：
2016-01-01
影响因子：
6.7
通讯作者：
Wu, Whei-Fen
中科院分区：
文献类型：
--
作者：
Chang, Chun-Yang;Hu, Hui-Ting;Wu, Whei-Fen
在大肠杆菌中，RcsA是cps（荚膜多糖合成）基因转录的阳性激活因子，可被Lon蛋白酶降解。在lon突变体中，RcsA的积累导致荚膜多糖的过表达。在先前的研究中，ClpYQ（HslUV）蛋白酶的过量产生抑制cpsB：：lacZ的表达，但没有直接观察表明ClpYQ降解RcsA。通过MBP-RcsA融合蛋白，我们表明RcsA激活了cpsB：：lacZ的表达，并且可以被SG 22622（lon（+））中的Lon蛋白酶快速降解。随后，在细菌菌株SG 22623（Ion）和AC 3112（Ion clpY clpQ）中进行的比较半衰期实验表明，AC 3112中的RcsA转换速率相对较慢，并且RcsA在30 ℃或41 ℃下稳定。此外，ClpY可以在体外下拉测定中与RscA相互作用，并且在ClpYQ蛋白酶的存在下在41 ° C下观察到RcsA的更快速降解。因此，我们得出结论，RcsA确实被ClpYQ蛋白酶蛋白水解。(C)2016年爱思唯尔有限公司。All rights reserved.
In Escherichia coli, RcsA, a positive activator for transcription of cps (capsular polysaccharide synthesis) genes, is degraded by the Lon protease. In lon mutant, the accumulation of RcsA leads to overexpression of capsular polysaccharide. In a previous study, overproduction of ClpYQ(HslUV) protease represses the expression of cpsB::lacZ, but there has been no direct observation demonstrating that ClpYQ degrades RcsA. By means of a MBP-RcsA fusion protein, we showed that RcsA activated cpsB::lacZ expression and could be rapidly degraded by Lon protease in SG22622 (lon(+)). Subsequently, the comparative half-life experiments performed in the bacterial strains SG22623 (lon) and AC3112 (Ion clpY clpQ) indicated that the RcsA turnover rate in AC3112 was relatively slow and RcsA was stable at 30 degrees C or 41 degrees C. In addition, ClpY could interact with RscA in an in vitro pull-down assay, and the more rapid degradation of RcsA was observed in the presence of ClpYQ protease at 41 degrees C. Thus, we conclude that RcsA is indeed proteolized by ClpYQ protease. (C) 2016 Elsevier GmbH. All rights reserved.