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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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