IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Induction of RpoS degradation by the two-component system regulator RstA in Salmonella
Autor/es:
CABEZA, M. L.; SONCINI, F. C.; GARCÍA VÉSCOVI, E.
Lugar:
Mar del Plata, Argentina
Reunión:
Congreso; XLIII Reunión anual; 2007
Institución organizadora:
Sociedad de Investigación en Bioquímica y Biología Molecular
Resumen:
Bacteria sense environmental conditions using a variety of strategies. Among them, two-component systems are the predominant form of signal transduction used by prokaryotes torespond to different kind of stresses. We found that the expression of RstA, the regulator of the two component system RstA/RstB, is able to down-regulate sigmaS (RpoS) levels in Salmonella. We determined that this regulation does not occur neither at the transcriptional nor at the translational level, but it alters RpoS protein turn-over. We showed that RstA expression increases three times RpoS degradation rate, using a mechanism that remains unknown. However,we found that it is independent of the ClpP/MviA pathway, the unique RpoS proteolytic route described up to now.We also established that none of the other three mayor proteases of Salmonella(Lon, HslV and HlfB) are envolved in the RstA-dependent degradation of RpoS. Besides, we found that a strain overproducing RstA decreases biofilm formation, while an rstA mutant strain shows a moderate increase in this process. As biofilm biogenesis is RpoS-dependent, we attribute this effect to the lower content of RpoS displayed by the RstA-producing strains. In sum, we unraveled the existence of a new mechanism for RpoS degradation mediated by the expression of RstAin Salmonella.