IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Mechanism of signal transduction by the thermosensor DesK from Bacillus subtilis”.
Autor/es:
ALBANESI D; MARTÍN M; BUSCHIAZZO A; TRAJTENBERG F; MANSILLA MC; HAOUZ A; ALZARI P; DE MENDOZA D
Lugar:
Carlos Paz, Argentina
Reunión:
Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008
Resumen:
The Bacillus subtilis Des pathway is composed of the membrane D5- acyl lipid desaturase and the two component system DesK/DesR. DesK is a histidine kinase located in the membrane and DesR is a cytoplasmatic response regulator that binds specifically to the Pdes promoter. Induction of the Des pathway is brought about by the ability of DesK to assume different signaling states in response to changes in membrane fluidity. An increase in the proportion of ordered membrane lipids favors a kinase-dominant state of DesK leading to phosphorylation of DesR and activation of des transcription while a decrease in the phase transition temperature of the phospholipids favors the phosphatase activity of DesK promoting DesR-P dephosphorylation and turning off the expression of des. We undertook structural studies in order to characterize the signaling states corresponding to the different activities associated with the cytoplasmic region of DesK and to gain further insights into the mechanism by which this sensor protein can adjust its signaling state in response to changes in membrane lipid fluidity. Here, we describe the crystal structure of the complete soluble domain of DesK in two conformational states. Structureinspired hypotheses for the distinct catalytic mechanisms and for signal transduction through the membrane to the cytoplasmic domain will be discussed.