title: LOV Histidine Kinase Modulates the General Stress Response System and Affects the virB Operon Expression in Brucella abortus.
abstract: Brucella is the causative agent of the zoonotic disease brucellosis, and its success as an intracellular pathogen relies on its ability to adapt to the harsh environmental conditions that it encounters inside the host. The Brucella genome encodes a sensor histidine kinase containing a LOV domain upstream from the kinase, LOVHK, which plays an important role in light-regulated Brucella virulence. In this report we study the intracellular signaling pathway initiated by the light sensor LOVHK using an integrated biochemical and genetic approach. From results of bacterial two-hybrid assays and phosphotransfer experiments we demonstrate that LOVHK functionally interacts with two response regulators: PhyR and LovR, constituting a functional two-component signal-transduction system. LOVHK contributes to the activation of the General Stress Response (GSR) system in Brucella via PhyR, while LovR is proposed to be a phosphate-sink for LOVHK, decreasing its phosphorylation state. We also show that in the absence of LOVHK the expression of the virB operon is down-regulated. In conclusion, our results suggest that LOVHK positively regulates the GSR system in vivo, and has an effect on the expression of the virB operon. The proposed regulatory network suggests a similar role for LOVHK in other microorganisms.
authors.affiliation: Laboratorio de Inmunología y Microbiología Molecular, Fundación Instituto Leloir (IIBBA-CONICET), Buenos Aires, Argentina.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Sycz
authors.affiliation: Laboratorio de Inmunología y Microbiología Molecular, Fundación Instituto Leloir (IIBBA-CONICET), Buenos Aires, Argentina.
authors.forename: Mariela Carmen
authors.initials: MC
authors.lastname: Carrica
authors.affiliation: Department of Plant Biology, Carnegie Institution for Science, Stanford, California, United States of America.
authors.forename: Tong-Seung
authors.initials: TS
authors.lastname: Tseng
authors.affiliation: Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California, United States of America.
authors.forename: Roberto A
authors.initials: RA
authors.lastname: Bogomolni
authors.affiliation: Department of Plant Biology, Carnegie Institution for Science, Stanford, California, United States of America.
authors.forename: Winslow R
authors.initials: WR
authors.lastname: Briggs
authors.affiliation: Laboratorio de Inmunología y Microbiología Molecular, Fundación Instituto Leloir (IIBBA-CONICET), Buenos Aires, Argentina.
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Goldbaum
authors.affiliation: Laboratorio de Inmunología y Microbiología Molecular, Fundación Instituto Leloir (IIBBA-CONICET), Buenos Aires, Argentina.
authors.forename: Gastón
authors.initials: G
authors.lastname: Paris
mesh_terms: D002003:Brucella abortus / Q000201:enzymology / Q000235:genetics*; D005798:Genes, Bacterial; D000071677:Histidine Kinase; D009876:Operon; D011494:Protein Kinases / Q000378:metabolism*; D012329:RNA, Bacterial / Q000302:isolation & purification; D013312:Stress, Physiological; D020798:Two-Hybrid System Techniques
chemical_list: D012329:RNA, Bacterial; D011494:Protein Kinases; D000071677:Histidine Kinase