Regulated proteolysis: control of the Escherichia coli sigma(E)-dependent cell envelope stress response.
Regulated proteolysis: control of the Escherichia coli sigma(E)-dependent cell envelope stress response.
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DOI：
10.1007/978-94-007-5940-4_6
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发表时间：
2013-01-01
影响因子：
--
通讯作者：
Ades, Sarah E
中科院分区：
文献类型：
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作者：
Barchinger, Sarah E;Ades, Sarah E
在过去的十年里，调节性蛋白水解酶已经成为从细菌到人类的所有生物体中跨膜信号转导的范例。这些保守的蛋白分解途径共有一个共同的设计，涉及两种蛋白酶对膜结合的调节蛋白的顺序蛋白分解。蛋白水解酶将不活跃的膜结合形式的调节器释放到细胞质中，在那里它执行细胞功能。通过调节蛋白分解进行信号转导的最具代表性的例子之一是控制大肠杆菌中依赖于西格玛(E)的细胞被膜应激反应的途径。在非应激细胞中，Sigma(E)被跨膜反Sigma因子RseA隔离在膜上。破坏细胞被膜并干扰外膜蛋白(OMP)的正确折叠的压力激活了蛋白分解途径。未折叠的OMPS的C末端残基与内膜蛋白酶DEGS结合，启动蛋白水解级联反应。DEGS去除了RseA的周质结构域，为途径中的下一种蛋白酶RseP创造了底物。RseP在调节的膜内蛋白分解(RIP)过程中在周质区域裂解RseA。剩余的RseA片段被释放到细胞质中，并在接头蛋白SspB的帮助下被依赖于ATP的蛋白酶ClpXP完全降解，从而释放sigma(E)来重新编程基因表达。越来越多的证据表明，控制Sigma(E)反应的整个蛋白质分解框架被用来调节整个细菌世界中类似的反Sigma因子/Sigma因子对，并已被适应于识别各种各样的信号和控制系统，从包膜应激反应、孢子形成、毒力和铁铁载体摄取。在这一章中，我们回顾了对Sigma(E)系统的广泛的生理、生化和结构研究，这些研究为这一受调控的蛋白分解信号转导途径的机制基础提供了显著的见解。这些研究揭示了适用于生命所有领域的相关蛋白水解酶和调节蛋白分解途径的设计原则。
Over the past decade, regulatory proteolysis has emerged as a paradigm for transmembrane signal transduction in all organisms, from bacteria to humans. These conserved proteolytic pathways share a common design that involves the sequential proteolysis of a membrane-bound regulatory protein by two proteases. Proteolysis releases the regulator, which is inactive in its membrane-bound form, into the cytoplasm where it performs its cellular function. One of the best-characterized examples of signal transduction via regulatory proteolysis is the pathway governing the sigma(E)-dependent cell envelope stress response in Escherichia coli. In unstressed cells, sigma(E) is sequestered at the membrane by the transmembrane anti-sigma factor, RseA. Stresses that compromise the cell envelope and interfere with the proper folding of outer membrane proteins (OMPs) activate the proteolytic pathway. The C-terminal residues of unfolded OMPs bind to the inner membrane protease, DegS, to initiate the proteolytic cascade. DegS removes the periplasmic domain of RseA creating a substrate for the next protease in the pathway, RseP. RseP cleaves RseA in the periplasmic region in a process called regulated intramembrane proteolysis (RIP). The remaining fragment of RseA is released into the cytoplasm and fully degraded by the ATP-dependent protease, ClpXP, with the assistance of the adaptor protein, SspB, thereby freeing sigma(E) to reprogram gene expression. A growing body of evidence indicates that the overall proteolytic framework that governs the sigma(E) response is used to regulate similar anti-sigma factor/sigma factor pairs throughout the bacterial world and has been adapted to recognize a wide variety of signals and control systems as diverse as envelope stress responses, sporulation, virulence, and iron-siderophore uptake. In this chapter, we review the extensive physiological, biochemical, and structural studies on the sigma(E) system that provide remarkable insights into the mechanistic underpinnings of this regulated proteolytic signal transduction pathway. These studies reveal design principles that are applicable to related proteases and regulatory proteolytic pathways in all domains of life.