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.