Role of adenosine nucleotides in the regulation of a stress-response transcription factor in Bacillus subtilis
Role of adenosine nucleotides in the regulation of a stress-response transcription factor in Bacillus subtilis
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DOI：
10.1006/jmbi.1996.0390
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发表时间：
1996-07-12
影响因子：
5.6
通讯作者：
Losick, R
中科院分区：
文献类型：
--
作者：
Alper, S;Dufour, A;Losick, R
RNA聚合酶sigma因子sigma（B）是枯草芽孢杆菌中的应激反应调节蛋白。sigma（B）的活性部分由RsbW（一种抑制sigma（B）的蛋白质）和RsbV（一种抵消这种抑制的蛋白质）控制。我们现在证明了纯化的RsbW能够与sigma（B）或RsbV形成替代复合物。σ（B）复合物中的σ（B）是转录失活的。RsbV逆转了这种抑制，隔离RsbW在RsbW。RsbV复合物，从而允许σ（B）保持游离和活性。与孢子形成转录因子sigma（F）的同源调节系统的组分之间的相互作用相反，RsbW与RsbV和sigma（B）的结合不需要腺苷核苷酸。涉及两个调节系统之间蛋白质交换的实验表明，RsbW及其在sigma（F）系统中的同系物SpoIIA B分别在与RsbV和sigma（B）以及SpoIIA和sigma（F）的结合中表现出强烈的偏好性，并且这两个系统之间结合的核苷酸依赖性的差异可归因于RsbW和SpoIIA B之间的差异。在以前的结果的确认和扩展，我们表明，RsbW也是一种蛋白激酶，使用ATP磷酸化RsbV，从而阻止RsbV的能力，结合RsbW和激活转录。观察到RsbW介导的RsbV有效磷酸化所需的ATP浓度与RsbW抑制之间存在密切相关性。RsbV复合物的形成，以及σ（B）-定向转录的抑制。这些结果与以下假设一致：在某些应激条件下sigma（B）的激活是由于细胞ATP水平的降低。(C)1996年学术出版社
The RNA polymerase sigma factor sigma(B) is a stress-response regulatory protein in Bacillus subtilis. The activity of sigma(B) is controlled in part by RsbW, a protein that inhibits sigma(B), and RsbV, a protein that counteracts this inhibition. We now demonstrate that purified RsbW is capable of forming alternative complexes with either sigma(B) or RsbV. sigma(B) in the RsbW .sigma(B) complex was transcriptionally inactive. RsbV reversed this inhibition by sequestering RsbW in a RsbW . RsbV complex, thereby allowing sigma(B) to remain free and active. In contrast to interactions among the components of the homologous regulatory system for the sporulation transcription factor sigma(F), the binding of RsbW to RsbV and sigma(B) did not require adenosine nucleotides. Experiments involving the exchange of proteins between the two regulatory systems demonstrated that RsbW and its homolog in the sigma(F) system, SpoIIAB, exhibit strong preference in binding to RsbV and sigma(B), and SpoIIAA and sigma(F), respectively, and that the difference in nucleotide-dependence of binding between these two systems is attributable to a difference between RsbW and SpoIIAB. In confirmation and extension of previous results, we show that RsbW is also a protein kinase that uses ATP to phosphorylate RsbV, thereby blocking the capacity of RsbV to bind to RsbW and activate transcription. A close correlation was observed between the concentration of ATP required for efficient RsbW-mediated phosphorylation of RsbV, inhibition of RsbW . RsbV complex formation, and inhibition of sigma(B)-directed transcription. These results are consistent with the hypothesis that activation of sigma(B) under certain stress conditions is due to a decrease in cellular ATP levels. (C) 1996 Academic Press Limited