Dynamic transformation of a cell-sized liposome containing ganglioside

Abstract

It is important to understand the physicochemical mechanisms that are responsible for the morphological changes in the cell membrane in the presence of various stimuli such as osmotic pressure. Role of micro domains such as lipid rafts in cellular processes is now beginning to unfold. In this study, we examined how constituent molecules affect the dynamical movement of liposomes. We used cell sized lipid vesicles to enable direct observation of these changes. We observed the effect of ganglioside (GM1) to osmotic stress induced membrane transformation in homogeneous and heterogeneous liposomes. Interestingly, it was observed that for the formation of sphero-stomatocyte there exists particular critical cut-off concentration. Also in the case of heterogeneous liposomes it was observed that at 10% molar ratio of GM1 almost all domains pinched out from the vesicles, forming their own homogeneous liposomes. Incorporation of GM1 into membrane leads to an increase of the line tension. Thus, necessary proteins can find themselves in one common raft and start the corresponding cascade of reactions.