The RcsC/RcsD/RcsB system in Salmonella typhimurium: a Bacterial Two-Hybrid Analysis.

MARIA DE LAS MERCEDES PESCARETTI; FABIAN E. LOPEZ; ROBERTO MORERO; MONICA A. DELGADO

San Miguel de Tucuman- Tucuman

Congreso; XLV Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology; 2009

The RcsC/RcsD/RcsB system in Salmonella typhimurium: a bacterial two-hybrid analysis. Maria de las Mercedes Pescaretti, Fabian E. Lopez, Roberto Morero, and Monica A. Delgado Dpto Bqca de la Nutricion-INSIBIO/Inst. Qca Biologica (CONICET-UNT) Tucuman. merpescaretti@hotmail.com The Rcs phosphorelay is a adaptive response system composed of three proteins: the sensor RcsC, the cognate response regulator RcsB; and the intermediary in the phosphoryl transfer RcsD. Has been described that the flow of phosphoryl groups through the Rcs phosphorelay can occur in following way RcsC¡úRcsD¡úRcsB. At present, the signal that activates the Rcs system has not been determined. We have demonstrated in a previous study that the overexpression of rcsB modulates the RcsB-dependent genes in an rcsC or rcsD mutant but not in the doble mutant. These results suggest that only RcsB-P, the RcsB phosphorylated form, is able to induce this modulation, and we postulated that the RcsB-P would occur by two or more different pathways. The goal of present work was study the possible phosphorelay pathways. In this work we used the two-hybrid assay (BACTH), consisting of the reconstitution of the adenylate cyclase activity in E. coli when two target proteins interacts in vivo in bacteria, measured by b-galactosidase activity. In this assay we probe the RcsC, RcsD and RcsB interaction to define the Rcs phosphorelay transduction mechanism.