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Wang Z, Zhao S, Li Y, Zhang K, Mo F, Zhang J, Hou Y, He L, Liu Z, Wang Y, Xu Y, Wang H, Buck M, Matthews SJ, Liu B. RssB-mediated σ S Activation is Regulated by a Two-Tier Mechanism via Phosphorylation and Adaptor Protein - IraD. J Mol Biol 2021; 433:166757. [PMID: 33346011 DOI: 10.1016/j.jmb.2020.166757] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 11/15/2022]
Abstract
Regulation of bacterial stress responding σS is a sophisticated process and mediated by multiple interacting partners. Controlled proteolysis of σS is regulated by RssB which maintains minimal level of σS during exponential growth but then elevates σS level while facing stresses. Bacteria developed different strategies to regulate activity of RssB, including phosphorylation of itself and production of anti-adaptors. However, the function of phosphorylation is controversial and the mechanism of anti-adaptors preventing RssB-σS interaction remains elusive. Here, we demonstrated the impact of phosphorylation on the activity of RssB and built the RssB-σS complex model. Importantly, we showed that the phosphorylation site - D58 is at the interface of RssB-σS complex. Hence, mutation or phosphorylation of D58 would weaken the interaction of RssB with σS. We found that the anti-adaptor protein IraD has higher affinity than σS to RssB and its binding interface on RssB overlaps with that for σS. And IraD-RssB complex is preferred over RssB-σS in solution, regardless of the phosphorylation state of RssB. Our study suggests that RssB possesses a two-tier mechanism for regulating σS. First, phosphorylation of RssB provides a moderate and reversible tempering of its activity, followed by a specific and robust inhibition via the anti-adaptor interaction.
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Affiliation(s)
- Zhihao Wang
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China; Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, SW7 2AZ London, United Kingdom
| | - Siyu Zhao
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China
| | - Yanqing Li
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China
| | - Kaining Zhang
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China
| | - Fei Mo
- School of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Jiye Zhang
- School of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Yajing Hou
- School of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Langchong He
- School of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Zhijun Liu
- National Facility for Protein Science, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Yawen Wang
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China
| | - Yingqi Xu
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, SW7 2AZ London, United Kingdom
| | - Hongliang Wang
- School of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Martin Buck
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, SW7 2AZ London, United Kingdom
| | - Steve J Matthews
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, SW7 2AZ London, United Kingdom
| | - Bing Liu
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China; Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, SW7 2AZ London, United Kingdom; Instrument Analysis Center of Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
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Bryan D, El-Shibiny A, Hobbs Z, Porter J, Kutter EM. Bacteriophage T4 Infection of Stationary Phase E. coli: Life after Log from a Phage Perspective. Front Microbiol 2016; 7:1391. [PMID: 27660625 PMCID: PMC5014867 DOI: 10.3389/fmicb.2016.01391] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/23/2016] [Indexed: 01/26/2023] Open
Abstract
Virtually all studies of phage infections investigate bacteria growing exponentially in rich media. In nature, however, phages largely encounter non-growing cells. Bacteria entering stationary phase often activate well-studied stress defense mechanisms that drastically alter the cell, facilitating its long-term survival. An understanding of phage-host interactions in such conditions is of major importance from both an ecological and therapeutic standpoint. Here, we show that bacteriophage T4 can efficiently bind to, infect and kill E. coli in stationary phase, both in the presence and absence of a functional stationary-phase sigma factor, and explore the response of T4-infected stationary phase cells to the addition of fresh nutrients 5 or 24 h after that infection. An unexpected new mode of response has been identified. "Hibernation" mode is a persistent but reversible dormant state in which the infected cells make at least some phage enzymes, but halt phage development until appropriate nutrients become available before producing phage particles. Our evidence indicates that the block in hibernation mode occurs after the middle-mode stage of phage development; host DNA breakdown and the incorporation of the released nucleotides into phage DNA indicate that the enzymes of the nucleotide synthesizing complex, under middle-mode control, have been made and assembled into a functional state. Once fresh glucose and amino acids become available, the standard lytic infection process rapidly resumes and concentrations of up to 10(11) progeny phage (an average of about 40 phage per initially present cell) are produced. All evidence is consistent with the hibernation-mode control point lying between middle mode and late mode T4 gene expression. We have also observed a "scavenger" response, where the infecting phage takes advantage of whatever few nutrients are available to produce small quantities of progeny within 2 to 5 h after infection. The scavenger response seems able to produce no more than an average of one phage per originally available cell, and few if any further progeny are produced by cells in this mode even if fresh nutrients are made available later.
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Affiliation(s)
- Daniel Bryan
- Kutter Bacteriophage Lab, The Evergreen State College Olympia, WA, USA
| | - Ayman El-Shibiny
- Kutter Bacteriophage Lab, The Evergreen State CollegeOlympia, WA, USA; Biomedical Sciences, University of Science and Technology, Zewail City of Science and TechnologyGiza, Egypt; Faculty of Environmental Agricultural Sciences, Arish UniversityArish, Egypt
| | - Zack Hobbs
- Kutter Bacteriophage Lab, The Evergreen State College Olympia, WA, USA
| | - Jillian Porter
- Kutter Bacteriophage Lab, The Evergreen State College Olympia, WA, USA
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