Human Serotonin Receptor 5-HT1A Preferentially Segregates to the Liquid Disordered Phase in Synthetic Lipid Bilayers

We demonstrate successful incorporation of the G protein coupled receptor 5-HT1A into giant unilamellar vesicles using an agarose rehydration method. With direct observation using fluorescence techniques, we report preferential segregation of 5-HT1A into the cholesterol-poor liquid disordered phase of the membrane, contradicting previous reports of lipid raft segregation. Furthermore, altering the concentration of cholesterol and sphingomyelin in ternary mixtures does not alter 5-HT1A segregation into the liquid disordered phase.