IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Cool adaptation: An electrostatic switch defines the signaling state of thermosensor DesK
Autor/es:
INDA, MARÍA EUGENIA; MICHEL VANDENBRANDEN; DIEGO DE MENDOZA; JEAN-MARIE RUYSSCHAERT; LARISA CYBULSKI
Lugar:
Carlos Paz
Reunión:
Congreso; XLII Sociedad Argentina de Biofísica; 2013
Institución organizadora:
Sociedad Argentina de Biofísica
Resumen:
DesK is a multipass transmembrane protein that allows the bacterium Bacillus subtilis to adjust the levels of unsaturated fatty acids required to optimize membrane lipid fluidity after a cold stress. This is achieve by its bifunctional cytoplasmic catalytic domain that alternates between kinase/ phosphatase activity. Temperature sensing involves a built-in instability caused by a group of hydrophilic residues, called ?Sunken Buoy? (SB) motif located near the amino terminus of the first transmembrane (TM)segment. These residues are buried in the lipid phase at low temperature and partially ?buoy? to the aqueous phase at higher temperature with the thinning of the membrane, promoting the required conformational change1. Nevertheless, the core question, still remains: ?how is the information sensed by the transmembrane region converted into a rearrangement in the cytoplasmic catalytic domain to control DesK activity?? Here we identify ?linker region? (KSRKERERLEEK) that connects the TM sensing domain with the cytoplasmic catalytic domain. Our results uphold the view that the linker is endowed with a helix/random coil conformational duality mechanistically exploited to transmit temperature-dependent conformational changes from the transmembrane to the intracellular region. We also assess the role of lipids charges variations as well as ionic force in the interaction of the linker with the membrane interphase modulating kinase to phosphatase activity ratio. 1. Cybulski, Martin, Mansilla, Fernandez, de Mendoza. Curr. Biology. 2010. 1539