INVESTIGADORES
DE MENDOZA Diego
congresos y reuniones científicas
Título:
The molecular logic of cold sensing in bacteria
Autor/es:
DIEGO DE MENDOZA
Lugar:
Puerto Varas
Reunión:
Congreso; LV Reunion Anual Sociedad de Biologia de Chile; 2012
Institución organizadora:
Sociedad de Biologia de Chile
Resumen:
CONFERENCIA PLENARIA LOGICA MOLECULAR DE LA DETECCION DE FRIO EN BACTERIAS (The molecular logic of cold sensing in bacteria). de Mendoza, D. Instituto de Biología Molecular y Celular de Rosario y Universidad Nacional de Rosario. Rosario. Argentina The ability of bacteria to control the biophysical properties of their membrane phospholipids allows them to thrive in a wide range of physical environments. When bacteria are exposed to temperatures below those of their normal conditions, the lipids of their membrane become rigidified, leading to a suboptimal functioning of cellular activities. These organisms can acclimate to such new conditions by an increase in the desaturation of the acyl chain of membrane phospholipids. Phospholipids containing unsaturated fatty acids have a much lower transition temperature than those lipids made of saturated fatty acids. As a result, the physical properties (fluidity) of the membrane lipids return to their original state, or close to it, with restoration of normal cell activity at the lower temperature. We discovered that in the model Gram-positive bacterium Bacillus subtilis the transcription of the gen des, coding for an acyl lipid desaturase, is controlled by a biological thermometer that senses changes in the membrane properties due to abrupt temperature change. This thermosensor, named DesK, is a bifunctional histidin kinase/phosphatase that senses membrane biophysical properties and transmits this signal to the transcriptional apparatus. In this talk, experimental evidence for the regulation of the distinct DesK catalytic mechanisms and for signal transduction through the membrane to the cytoplasmic domain will be discussed.