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Mycobacterium tuberculosis protease MarP activates a peptidoglycan hydrolase during acid stress.

TitleMycobacterium tuberculosis protease MarP activates a peptidoglycan hydrolase during acid stress.
Publication TypeJournal Article
Year of Publication2017
AuthorsBotella H, Vaubourgeix J, Lee MHee, Song N, Xu W, Makinoshima H, Glickman MS, Ehrt S
JournalEMBO J
Volume36
Issue4
Pagination536-548
Date Published2017 Feb 15
ISSN1460-2075
Abstract

Mycobacterium tuberculosis (Mtb) can persist in the human host in a latent state for decades, in part because it has the ability to withstand numerous stresses imposed by host immunity. Prior studies have established the essentiality of the periplasmic protease MarP for Mtb to survive in acidified phagosomes and establish and maintain infection in mice. However, the proteolytic substrates of MarP that mediate these phenotypes were unknown. Here, we used biochemical methods coupled with supravital chemical probes that facilitate imaging of nascent peptidoglycan to demonstrate that during acid stress MarP cleaves the peptidoglycan hydrolase RipA, a process required for RipA's activation. Failure of RipA processing in MarP-deficient cells leads to cell elongation and chain formation, a hallmark of progeny cell separation arrest. Our results suggest that sustaining peptidoglycan hydrolysis, a process required for cell elongation, separation of progeny cells, and cell wall homeostasis in growing cells, may also be essential for Mtb's survival in acidic conditions.

DOI10.15252/embj.201695028
Alternate JournalEMBO J.
PubMed ID28057704