INIBIOLP   05426
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE LA PLATA "PROF. DR. RODOLFO R. BRENNER"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Nanomechanics of asymmetric supported lipid bilayers with raft-like domains
Autor/es:
ROMINA F. VAZQUEZ; IVÁN ORTEGA-BLAKE; ARMANDO ANTILLÓN; SABINA M. MATÉ; ERASMO OVALLE-GARCÍA; CARLOS MUÑOZ-GARAY
Lugar:
Heidelberg
Reunión:
Simposio; Life at the Periphery: Mechanobiology of the Cell Surface; 2021
Institución organizadora:
EMBO-EMBL
Resumen:
The asymmetric distribution of phospholipids that exists in the membrane confers the twoleaflets different potentials to form raft-like domains as next to no sphingolipids are present inthe inner leaflet. The architecture and properties of lipid domains in asymmetric systems aretherefore of particular interest to further the understanding of how lipid domains may form andact in vivo in cellular processes. In this work, we characterized the structure andnanomechanics of asymmetric raft-like domains through AFM imaging and Forcespectroscopy measurements. Asymmetric supported lipid bilayers (SLBs) were formed byincorporating N-palmitoyl-sphingomyelin into the outer leaflet of preformed1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC)/Cholesterol (Chol) SLBs throughcyclodextrin?mediated lipid exchange. Asymmetric lipid domains were analyzed and theirproperties were compared with their symmetric counterparts. Differences in size andmorphology were observed, with asymmetric domains being smaller and moreinterconnected. Both types of domains (asymmetric and symmetric) showed similarmechanical stability in terms of rupture forces and Young?s moduli. Notwithstanding, forcecurves in asymmetric domains presented two rupture events attributed to a liquid disordered(Ld) proximal hemilayer that collapsed first due to distal compression and a liquid ordered(Lo) outer hemilayer that was punctured in a second event at higher forces. Symmetric Lo/Lodomains showed typical single rupture events at forces corresponding to a Lo phase.Interleaflet coupling in asymmetric Lo/Ld domains could also be inferred, i.e., the presence ofthe Lo outer leaflet increased the degree of order of the DOPC/Chol inner leaflet. This couldhave implications in signaling processes across the membrane. This experimental approachenhances the applicability of membrane models allowing studies on membrane propertiesand protein function using a more accurate version of biological membranes.