Behavior of GM3 ganglioside in lipid monolayers mimicking rafts or fluid phase in membranes.
We studied the interaction of GM3 ganglioside with sphingomyelin (SM) and palmitoyl-oleoyl-phosphatidylcholine (POPC) in Langmuir monolayers mimicking, respectively, raft and fluid phase of a cellular membrane, by surface pressure measurements and fluorescence microscopy. No difference was observed in the behavior of SM-GM3 and POPC-GM3 monolayers. In both cases, a GM3 threshold concentration has been underlined between 20 and 40 mol%. Below this threshold, SM-GM3 and POPC-GM3 monolayers behave ideally, suggesting that GM3 and host lipid would form separated domains. On the contrary, above the threshold, a condensation of monolayers is observed. This could be due to a partial solubilisation of GM3 in host lipid, leading to a change in orientation of GM3 molecules at the air-water interface.
Grauby-Heywang
Christine
C
Centre de Physique Moléculaire Optique et Hertzienne (CPMOH), UMR 5798 du CNRS, Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence Cedex, France. ch.heywang@cpmoh.u-bordeaux1.fr
Turlet
Jean-Marie
JM
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005679:G(M3) Ganglioside / Q000737:chemistry*; D066298:In Vitro Techniques; D008051:Lipid Bilayers / Q000737:chemistry; D008560:Membrane Fluidity; D021962:Membrane Microdomains / Q000737:chemistry; D008567:Membranes, Artificial; D008856:Microscopy, Fluorescence; D012995:Solubility; D013499:Surface Properties
D005679:G(M3) Ganglioside; D008051:Lipid Bilayers; D008567:Membranes, Artificial