Negative regulation of the proteolytic activation of a developmental transcription factor in Bacillus subtilis.
Negative regulation of the proteolytic activation of a developmental transcription factor in Bacillus subtilis.
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DOI：
10.1073/pnas.95.6.3162
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发表时间：
1998-03
影响因子：
11.1
通讯作者：
O. Resnekov;R. Losick
中科院分区：
文献类型：
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作者：
O. Resnekov;R. Losick
枯草芽孢杆菌的孢子形成转录因子sigmaK受一条信号转导通路控制，该通路在非活性前体蛋白Pro-sigmaK的蛋白降解过程中起作用。Pro-sigmaK向sigmaK的转化需要可能的加工酶SpoIVFB，并受调节蛋白SpoIVFA和BofA的调控。我们改造营养细胞，通过诱导原蛋白的合成来进行原-sigmaK的加工，原蛋白是假定的加工酶的一种修改形式，以及它在生长过程中的两个调节因子。结果表明：(I)修饰的SpoIVFB是实现Pro-sigmaK加工所必需的唯一产孢蛋白；(Ii)SpoIVFA刺激加工，显然是通过保护加工酶不被降解；(Iii)BofA以不涉及SpoIVFB降解的方式抑制加工；(Iv)BofA对SpoIVFB的抑制依赖于SpoIVFA。我们得出结论，BofA和SpoIVFA具有协同作用，是仅有的两种抑制SpoIVFB功能所需的产孢蛋白。我们的结果与以下观点一致，即Pro-sigmaK的激活是通过逆转BofA/SpoIVFA介导的对加工酶的抑制来实现的。
The sporulation transcription factor sigmaK of Bacillus subtilis is controlled by a signal transduction pathway that operates at the level of the proteolytic processing of the inactive precursor protein pro-sigmaK. The conversion of pro-sigmaK to sigmaK requires the putative processing enzyme SpoIVFB and is governed by the regulatory proteins SpoIVFA and BofA. We engineered vegetative cells to carry out processing of pro-sigmaK by inducing the synthesis of the proprotein, a modified form of the putative processing enzyme, and its two regulators during growth. The results showed that (i) modified SpoIVFB was the only sporulation protein necessary to achieve processing of pro-sigmaK; (ii) SpoIVFA stimulated processing, apparently by protecting the processing enzyme from degradation; (iii) BofA inhibited processing in a manner that did not involve degradation of SpoIVFB; and (iv) the inhibition of SpoIVFB by BofA was dependent on SpoIVFA. We conclude that BofA and SpoIVFA act synergistically and are the only two sporulation proteins needed to inhibit the function of SpoIVFB. Our results are consistent with the idea that activation of pro-sigmaK occurs by a reversal of the BofA/SpoIVFA-mediated inhibition of the processing enzyme.