WHAT IS MORE IMPORTANT FOR DESK ACTIVITY REGULATION: HEADGROUPS OR ACYL CHAINS OF LIPIDS?

MARTÍN, M.; CIRULLI, B. A.; DE MENDOZA, D.

Potrero de los Funes, San Luis

Congreso; 47 Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2011

DesK is the thermosensor of B. subtilis Des Pathway, the only example in nature where the mechanism of low temperature signals perception and transduction is well established and a functional connection between induced protein and cold adaptation demonstrated.Since DesK is a membrane-integrated kinase with sensing mechanisms relying on its five transmembrane segments (TMS), it represents an ideal system for studying the molecular mechanism of thermodetection and signal transduction. Changes in environmental temperature may induce changes in lipid properties that in turn would affect the dynamics of DesK TMS, leading to changes in the extra-membraneous parts resulting in signaling. To provide insight in this unique mechanism of signaling we studied the nature of the TMS-lipid interactions that are critical for sensing and signaling, analyzing the effect of bilayer thickness, lipid fluidity, lipid acyl chain packing as well as phospholipid headgroup on the autokinase activity of DesK. To this end, we biochemically characterized DesK proteoliposomes composed of different headgroup lipids containing variable fatty acyl chains. The results obtained in vitro complemented with in vivo experiments performed in B. subtillis phospholipids mutants, led us to conclude that theproperties of the acyl chains of membrane phospholipids are the main clue that regulates DesK activity.