title: The Rip1 protease of Mycobacterium tuberculosis controls the SigD regulon.
abstract: Regulated intramembrane proteolysis of membrane-embedded substrates by site-2 proteases (S2Ps) is a widespread mechanism of transmembrane signal transduction in bacteria and bacterial pathogens. We previously demonstrated that the Mycobacterium tuberculosis S2P Rip1 is required for full virulence in the mouse model of infection. Rip1 controls transcription in part through proteolysis of three transmembrane anti-sigma factors, anti-SigK, -L, and -M, but there are also Rip1-dependent, SigKLM-independent pathways. To determine the contribution of the sigma factors K, L, and M to the Δrip1 attenuation phenotype, we constructed an M. tuberculosis ΔsigKΔ sigL ΔsigM mutant and found that this strain fails to recapitulate the marked attenuation of Δrip1 in mice. In a search for additional pathways controlled by Rip1, we demonstrated that the SigD regulon is positively regulated by the Rip1 pathway. Rip1 cleavage of transmembrane anti-SigD is required for expression of SigD target genes. In the absence of Rip1, proteolytic maturation of RsdA is impaired. These findings identify RsdA/SigD as a fourth arm of the branched pathway controlled by Rip1 in M. tuberculosis.
authors.affiliation: Immunology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School, New York, New York, USA.
authors.forename: Jessica S
authors.initials: JS
authors.lastname: Schneider
authors.affiliation: Immunology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Sklar
authors.affiliation: Immunology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA Division of Infectious Diseases, Memorial Sloan Kettering Cancer Center, New York, New York, USA Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School, New York, New York, USA glickmam@mskcc.org.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Glickman
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D051379:Mice; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D018085:Regulon; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D012808:Sigma Factor; D010447:Peptide Hydrolases