THE LIGHT ACTIVATED PATHWAY TO VIRULENCE IN Brucella abortus

GASTON PARIS; MARIELA DEL CARMEN CARRICA; TONG-SENG TSENG; MARCUS FREDERICKSON; ROBERTO A. BOGOMOLNI; WINSLOW R. BRIGGS; FERNANDO A. GOLDBAUM

Tucumán, Argentina

Congreso; XLV Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2009

Sociedad Argentina de Investigación Bioquímica

Brucella is responsible of one of the world´s most widespread zoonotic diseases, causing miscarriage and infertility in animals and a febrile disease, known as Malta Fever in humans. Animal brucellosis is a enormous problem worldwide and is endemic in most areas of the world. Light, oxygen and voltage (LOV) proteins are a subset of the large and diverse PAS family that bind FMN and blue light receptors in plants, fungi and bacteria. Brucella genomes encode a 463 amino acid histidine kinase protein (LOV-HK) that contains three domains, a LOV domain at the N-terminus, a histidine kinase (HK) at the C-terminus and a PAS domain in between. Blue light absorption by the LOV-HK activates the autophosphorylation of the HK domain. LOV-HK works as photoreceptor that increase the virulence of B. abortus upon illumination. Using bacterial two-hybrid we have identified a single domain response regulator (RR) protein as the partner of LOV-HK. It was named as CheY-L because the similar organization to chemotaxis CheY proteins. The interaction between LOV-HK and CheY-L was confirmed by phosphotransfer assays. Bacterial two-hybrid assays also shown that CheY-L interacts with cytoplasmatic components of the flagella, FliM and FliG. We have identified CheY-L and flagellar proteins FliM and FliG as components of the signal transduction pathway initiated by light that regulates the virulence of Brucella.