title: A redox regulatory system critical for mycobacterial survival in macrophages and biofilm development.
abstract: Survival of M. tuberculosis in host macrophages requires the eukaryotic-type protein kinase G, PknG, but the underlying mechanism has remained unknown. Here, we show that PknG is an integral component of a novel redox homeostatic system, RHOCS, which includes the ribosomal protein L13 and RenU, a Nudix hydrolase encoded by a gene adjacent to pknG. Studies in M. smegmatis showed that PknG expression is uniquely induced by NADH, which plays a key role in metabolism and redox homeostasis. In vitro, RenU hydrolyses FAD, ADP-ribose and NADH, but not NAD+. Absence of RHOCS activities in vivo causes NADH and FAD accumulation, and increased susceptibility to oxidative stress. We show that PknG phosphorylates L13 and promotes its cytoplasmic association with RenU, and the phosphorylated L13 accelerates the RenU-catalyzed NADH hydrolysis. Importantly, interruption of RHOCS leads to impaired mycobacterial biofilms and reduced survival of M. tuberculosis in macrophages. Thus, RHOCS represents a checkpoint in the developmental program required for mycobacterial growth in these environments.
authors.affiliation: Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America.
authors.forename: Kerstin A
authors.initials: KA
authors.lastname: Wolff
authors.affiliation: Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America; Department of Biophysics and Biophysical Chemistry, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Andres H
authors.initials: AH
authors.lastname: de la Peña
authors.affiliation: Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America.
authors.forename: Hoa T
authors.initials: HT
authors.lastname: Nguyen
authors.affiliation: Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America.
authors.forename: Thanh H
authors.initials: TH
authors.lastname: Pham
authors.affiliation: Department of Biophysics and Biophysical Chemistry, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: L Mario
authors.initials: LM
authors.lastname: Amzel
authors.affiliation: Department of Biophysics and Biophysical Chemistry, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America; Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America; Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Sandra B
authors.initials: SB
authors.lastname: Gabelli
authors.affiliation: Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America.
authors.forename: Liem
authors.initials: L
authors.lastname: Nguyen
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D018441:Biofilms; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008264:Macrophages / Q000382:microbiology*; D020102:Mycobacterium smegmatis / Q000502:physiology*; D010084:Oxidation-Reduction; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins