UMass Chan Medical School Faculty Publications
UMMS Affiliation
Department of Microbiology and Physiological Systems
Publication Date
2021-10-26
Document Type
Article Preprint
Disciplines
Bacteria | Microbiology
Abstract
Cell wall peptidoglycan is a heteropolymeric mesh that protects the bacteria from internal turgor and external insults. In many rod-shaped bacteria, peptidoglycan synthesis for normal growth is achieved by two distinct pathways: the Rod complex, comprised of MreB, RodA and a cognate class B PBP, and the class A PBPs. In contrast to laterally-growing bacteria, pole-growing mycobacteria do not encode an MreB homolog and do not require SEDS protein RodA for in vitro growth. However, RodA contributes to survival of Mycobacterium tuberculosis in some infection models, suggesting that the protein could have a stress-dependent role in maintaining cell wall integrity. Under basal conditions, we find here that the subcellular distribution of RodA largely overlaps with that of the aPBP PonA1, and that both RodA and the aPBPs promote polar peptidoglycan assembly. Upon cell wall damage, RodA fortifies M. smegmatis against lysis and, unlike aPBPs, contributes to a shift in peptidoglycan assembly from the poles to the sidewall. Neither RodA nor PonA1 relocalize; instead, the redistribution of nascent cell wall parallels that of peptidoglycan precursor synthase MurG. Our results support a model in which mycobacteria balance polar growth and cell-wide repair via spatial flexibility in precursor synthesis and extracellular insertion.
Importance Peptidoglycan synthesis is a highly successful target for antibiotics. The pathway has been extensively studied in model organisms under laboratory-optimized conditions. In natural environments, bacteria are frequently under attack. Moreover the vast majority of bacterial species are unlikely to fit a single paradigm because of differences in growth mode and/or envelope structure. Studying cell wall synthesis under non-optimal conditions and in non-standard species may improve our understanding of pathway function and suggest new inhibition strategies. Mycobacterium smegmatis, a relative of several notorious human and animal pathogens, has an unusual polar growth mode and multi-layered envelope. In this work we challenged M. smegmatis with cell wall-damaging enzymes to characterize the roles of cell wall-building enzymes when the bacterium is under attack.
Keywords
Microbiology, peptidoglycan, mycobacteria
Rights and Permissions
The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license.
DOI of Published Version
10.1101/2021.10.26.465981
Source
bioRxiv 2021.10.26.465981; doi: https://doi.org/10.1101/2021.10.26.465981. Link to preprint on bioRxiv.
Journal/Book/Conference Title
bioRxiv
Repository Citation
Melzer ES, Kado T, García-Heredia A, Ramnaresh Gupta K, Meniche X, Morita YS, Sassetti CM, Rego EH, Siegrist MS. (2021). Cell wall damage reveals spatial flexibility in peptidoglycan synthesis and a non-redundant role for RodA in mycobacteria [preprint]. UMass Chan Medical School Faculty Publications. https://doi.org/10.1101/2021.10.26.465981. Retrieved from https://escholarship.umassmed.edu/faculty_pubs/2099
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Comments
This article is a preprint. Preprints are preliminary reports of work that have not been certified by peer review.