Biology subjects

Boutte, C.

Publications and source records attributed to Boutte, C..

4 recordsLinked to original sources

bioRxiv2022

PlrA (MSMEG_5223) is an essential polar growth regulator in Mycobacterium smegmatis

Mycobacteria expand their cell walls at the cell poles in a manner that is not well described at the molecular level. In this study, we identify a new factor, PlrA, involved in restricting peptidoglycan metabolism to the cell poles in Mycobacterium smegmatis. We show that PlrA localizes to the pole tips, and we identify its essential domain. We show that depletion of plrA pheno-copies depletion of polar growth factor Wag31, and that PlrA is involved in regulating polar peptidoglycan metabolism and the structure of the Wag31 polar foci.

microbiology↗

bioRxiv2022

Mycobacterial Serine/Threonine phosphatase PstP is phospho-regulated and localized to mediate control of cell wall metabolism

The mycobacterial cell wall is profoundly regulated in response to environmental stresses, and this regulation contributes to antibiotic tolerance. The reversible phosphorylation of different cell wall regulatory proteins is a major mechanism of cell wall regulation. Eleven Serine/Threonine protein kinases (STPKs) phosphorylate many critical cell wall-related proteins in mycobacteria. PstP is the sole serine/ threonine phosphatase, but few proteins have been verified as PstP substrates. PstP is itself phosphorylated but the role of its phosphorylation in regulating its activity has been unclear. In this study we aim to discover novel substrates of PstP in Mycobacterium tuberculosis (Mtb). We show in vitro that PstP dephosphorylates two regulators of peptidoglycan in Mtb, FhaA and Wag31. We also show that a phospho-mimetic mutation of T137 on PstP negatively regulates its catalytic activity against the cell wall regulators FhaA, Wag31, CwlM, PknB and PknA, and that the corresponding mutation in Mycobacterium smegmatis (Msmeg) causes mis-regulation of peptidoglycan in vivo. We show that PstP is localized to the septum, which likely restricts its access to certain substrates. These findings on the regulation of PstP provide insight into the control of cell wall metabolism in mycobacteria.

microbiology↗

bioRxiv2021

Arginine methylation helps SepIVA balance regulation of septation and elongation in Mycobacterium smegmatis

Growth of mycobacterial cells requires successful coordination between elongation and septation of the cell wall. However, it is not clear which factors directly mediate this coordination. Here, we studied the function and post-translational modification of an essential division factor, SepIVA, in Mycobacterium smegmatis. We find that SepIVA is arginine methylated, and that alteration of these methylation sites affects both septation and polar elongation of Msmeg. Furthermore, we show that SepIVA regulates the localization of MurG, and that this regulation may impact polar elongation. Finally, we map SepIVAs two regulatory functions to different sites on the protein: the N-terminus regulates elongation while the C-terminus regulates division. These results establish SepIVA as a regulator of both elongation and division and characterize a physiological role for protein arginine methylation sites for the first time in mycobacteria.

microbiology↗

bioRxiv2018

Biofilm-associated Mycobacterium abscessus cells have altered antibiotic tolerance and surface glycolipids in Artificial Cystic Fibrosis Sputum Media

Mycobacterium abscessus (Mab) is a biofilm-forming, multi-drug resistant, non-tuberculous mycobacterial (NTM) pathogen increasingly found in Cystic Fibrosis patients. Antibiotic treatment for these infections is often unsuccessful, partly due to Mabs high intrinsic antibiotic resistance. It is not clear whether antibiotic tolerance caused by biofilm formation also contributes to poor treatment outcomes. We studied the surface glycolipids and antibiotic tolerance of Mab biofilms grown in Artificial Cystic Fibrosis Sputum media in order to determine how they are affected by nutrient conditions that closely mimic infection. We found that Mab biofilms grown in ACFS display more of the virulence lipid trehalose dimycolate than biofilms grown in standard lab media. Biofilms in ACFS media also afford more protection against clinically important antibiotics than biofilms grown in lab media. These results indicate that Mab cell physiology in biofilms depends on environmental factors, and that nutrient conditions found within Cystic Fibrosis infections could contribute to both increased virulence and antibiotic tolerance.

microbiology↗