PHOSPHORYLATION OF OMPR BY THE OSMOSENSOR ENVZ MODULATES EXPRESSION OF THE OMPF AND OMPC GENES IN ESCHERICHIA-COLI
PHOSPHORYLATION OF OMPR BY THE OSMOSENSOR ENVZ MODULATES EXPRESSION OF THE OMPF AND OMPC GENES IN ESCHERICHIA-COLI
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DOI：
10.1073/pnas.86.16.6052
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发表时间：
1989-08-01
影响因子：
11.1
通讯作者：
INOUYE, M
中科院分区：
文献类型：
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作者：
FORST, S;DELGADO, J;INOUYE, M
EnvZ和OmpR是大肠杆菌中ompF和ompC表达的调节蛋白，属于调节-效应蛋白家族，对环境信号的反应至关重要。我们发现跨膜调节蛋白EnvZ的可溶性胞质结构域在体外被[. γ .- 32p]-ATP磷酸化。我们还证明，磷酸基团可以反过来转移到转录激活蛋白OmpR上。与EnvZ相连的磷酸基团的pH稳定性表明该分子含有磷酸组氨酸。EnvZ的不变性His-243对应于趋化调节蛋白CheA的磷酸化His-48。用缬氨酸取代His-243产生一个难以磷酸化的EnvZ，不能再催化磷酸盐向OmpR转移。此外，在。delta。含有envZ Val-243质粒的大肠杆菌envZ菌株，与携带野生型envZ质粒的细胞相比，ompC的表达提高了7倍。基于这些结果，我们提出了一个模型，在该模型中，OmpR的磷酸化状态调节ompF和ompC基因的表达。
EnvZ and OmpR, the regulatory proteins for ompF and ompC expression in Escherichia coli, belong to a modulator-effector family of regulatory proteins which are essential for the response to environmental signals. We show that the soluble cytoplasmic domain of the transmembrane modulator protein EnvZ is phosphorylated in vitro by [.gamma.-32P]-ATP. We also demonstrate that the phosphate group can, in turn, be transferred to the transcription activator protein OmpR. The pH stability properties of the phosphate groups linked to EnvZ indicate that this molecule contains histidyl phosphate. The invariant His-243 of EnvZ corresponds to the phosphorylated His-48 of the chemotactic modulator protein CheA. Substitution of His-243 with valine produces an EnvZ that is refractory to phosphorylation and can no longer catalyze the transfer of phosphate to OmpR. Furthermore, in a .DELTA.envZ strain of E. coli, containing the envZ Val-243 plasmid, ompC expression is elevated 7-fold relative to that found in cells carrying the wild-type envZ plasmid. Based on these results we propose a model in which the phosphorylated state of OmpR modulates the expression of the ompF and ompC genes.