Inhibition of regulated proteolysis by RseB
Inhibition of regulated proteolysis by RseB
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DOI：
10.1073/pnas.0611567104
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发表时间：
2007-03-06
影响因子：
11.1
通讯作者：
Sauer, Robert T.
中科院分区：
文献类型：
--
作者：
Cezairliyan, Brent O.;Sauer, Robert T.
大肠杆菌胞内应激反应是一种传感系统，当在周质中检测到错误折叠的孔蛋白时，该系统增加细胞质中应激基因的转录。这种反应是由DegS切割RseA（一种跨膜蛋白）的周质结构域引发的。RseA的跨膜和胞质部分的额外蛋白水解然后释放sigma（E）转录因子，其指导转录应答。我们发现，RseB蛋白，一个已知的负调节，抑制蛋白水解DegS在体外紧密结合到RseA的周质结构域。DegS切割的抑制需要RseB结合到结构不良的RseA结构域的C末端附近的保守区域，但是介导DegS识别和RseB结合的RseA序列不直接重叠。尽管RseA的DegS切割通常通过孔蛋白的C末端与DegS的PDZ结构域的结合来激活，但RseB抑制不依赖于这种激活机制。
The Escherichia coli envelope-stress response is a sensor system that increases transcription of stress genes in the cytoplasm when misfolded porins are detected in the periplasm. This response is initiated by DegS cleavage of the periplasmic domain of RseA, a transmembrane protein. Additional proteolysis of transmembrane and cytoplasmic portions of RseA then frees the sigma(E) transcription factor, which directs the transcriptional response. We show that RseB protein, a known negative regulator, inhibits proteolysis by DegS in vitro by binding tightly to the periplasmic domain of RseA. Inhibition of DegS cleavage requires RseB binding to a conserved region near the C terminus of the poorly structured RseA domain, but the RseA sequences that mediate DegS recognition and RseB binding do not overlap directly. Although DegS cleavage of RseA is normally activated by binding of the C termini of porins to the PDZ domain of DegS, RseB inhibition is independent of this activation mechanism.