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Lakey BD, Alberge F, Parrell D, Wright ER, Noguera DR, Donohue TJ. The role of CenKR in the coordination of Rhodobacter sphaeroides cell elongation and division. mBio 2023; 14:e0063123. [PMID: 37283520 PMCID: PMC10470753 DOI: 10.1128/mbio.00631-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 03/16/2023] [Accepted: 03/24/2023] [Indexed: 06/08/2023] Open
Abstract
Cell elongation and division are essential aspects of the bacterial life cycle that must be coordinated for viability and replication. The impact of misregulation of these processes is not well understood as these systems are often not amenable to traditional genetic manipulation. Recently, we reported on the CenKR two-component system (TCS) in the Gram-negative bacterium Rhodobacter sphaeroides that is genetically tractable, widely conserved in α-proteobacteria, and directly regulates the expression of components crucial for cell elongation and division, including genes encoding subunit of the Tol-Pal complex. In this work, we show that overexpression of cenK results in cell filamentation and chaining. Using cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET), we generated high-resolution two-dimensional (2D) images and three-dimensional (3D) volumes of the cell envelope and division septum of wild-type cells and a cenK overexpression strain finding that these morphological changes stem from defects in outer membrane (OM) and peptidoglycan (PG) constriction. By monitoring the localization of Pal, PG biosynthesis, and the bacterial cytoskeletal proteins MreB and FtsZ, we developed a model for how increased CenKR activity leads to changes in cell elongation and division. This model predicts that increased CenKR activity decreases the mobility of Pal, delaying OM constriction, and ultimately disrupting the midcell positioning of MreB and FtsZ and interfering with the spatial regulation of PG synthesis and remodeling. IMPORTANCE By coordinating cell elongation and division, bacteria maintain their shape, support critical envelope functions, and orchestrate division. Regulatory and assembly systems have been implicated in these processes in some well-studied Gram-negative bacteria. However, we lack information on these processes and their conservation across the bacterial phylogeny. In R. sphaeroides and other α-proteobacteria, CenKR is an essential two-component system (TCS) that regulates the expression of genes known or predicted to function in cell envelope biosynthesis, elongation, and/or division. Here, we leverage unique features of CenKR to understand how increasing its activity impacts cell elongation/division and use antibiotics to identify how modulating the activity of this TCS leads to changes in cell morphology. Our results provide new insight into how CenKR activity controls the structure and function of the bacterial envelope, the localization of cell elongation and division machinery, and cellular processes in organisms with importance in health, host-microbe interactions, and biotechnology.
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Affiliation(s)
- Bryan D. Lakey
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - François Alberge
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Daniel Parrell
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Elizabeth R. Wright
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Cryo-Electron Microscopy Research Center,Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Midwest Center for Cryo-Electron Tomography, Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Daniel R. Noguera
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Timothy J. Donohue
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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