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Gwin, C. M.

Publications and source records attributed to Gwin, C. M..

2 recordsLinked to original sources

An activator of a two-component system controls cell separation and intrinsic drug resistance in Mycobacterium tuberculosis

Unlike commonly studied rod-shaped bacteria, mycobacteria grow from their poles, requiring precise coordination between division and initiation of new pole growth. The mechanisms that mediate this transition are largely unknown, but likely represent a rich source of drug targets for the treatment of mycobacterial infections, including tuberculosis. Here, we identify TapA (MSMEG_3748/Rv1697) as a key regulator of this transition. TapA interacts with the sensor kinase MtrB at the septum to initiate a signaling cascade that ultimately results in the expression of the essential peptidoglycan hydrolases RipAB, amongst others, at the end of division. Loss of TapA disrupts division, dysregulates pole formation, and sensitizes Mycobacterium tuberculosis and other mycobacteria to several first and second-line TB antibiotics, establishing TapA as a potential therapeutic target, and defining a new link between cell cycle progression, envelope remodeling, and intrinsic antibiotic resistance in mycobacteria.

microbiology↗

Spatial segregation and aging of metabolic processes underlie phenotypic heterogeneity in mycobacteria

Individual cells within clonal populations of mycobacteria vary in size, growth rate, and antibiotic susceptibility. Heterogeneity is, in part, determined by LamA, a protein found exclusively in mycobacteria. LamA localizes to sites of new cell wall synthesis where it recruits proteins important for polar growth and establishing asymmetry. Here, we report that in addition to this function, LamA interacts with complexes involved in oxidative phosphorylation (OXPHOS) at a subcellular location distinct from cell wall synthesis. Importantly, heterogeneity depends on a unique extension of the mycobacterial ATP synthase, and LamA mediates the coupling between ATP production and cell growth in single cells. Strikingly, as single cells age, concentrations of proteins important for oxidative phosphorylation become less abundant, and older cells rely less on oxidative phosphorylation for growth. Together, our data reveal that central metabolism is spatially organized within a single mycobacterium and varies within a genetically identical population of mycobacteria. Designing therapeutic regimens to account for this heterogeneity may help to treat mycobacterial infections faster and more completely.

microbiology↗