Biphasic vesicle: instability induced by adsorption of proteins

Abstract

The recent discovery of a lateral organization in cell membranes due to small structures called 'rafts' has motivated a lot of biological and physico-chemical studies. A new experiment on a model system has shown a spectacular budding process with the expulsion of one or two rafts when one introduces proteins on the membrane. In this paper, we give a physical interpretation of the budding of the raft phase. An approach based on the energy of the system including the presence of proteins is used to derive a shape equation and to study possible instabilities. This model shows two different situations which are strongly dependent on the nature of the proteins: a regime of easy budding when the proteins are strongly coupled to the membrane and a regime of difficult budding.

Numerical study of the phase separation in binary lipid membrane containing protein inclusions under stationary shear flow

“…And the local inclusion concentration is denoted as r. The deformable membrane surface can be described by [x,y,h(x,y)], where h(x,y) is the off-plane displacement field for the local separation from the flat conformation. On basis of our previous work (Chen et al, 2008), the work of Allain and Amar (2004) and the work of Komura and Kodama (1997), the free energy functional of this continuous system could be expressed as…”

Multidomain and ground state configurations of two-phase vesicles

“…In a study of the instability of the vesicle owing to protein adsorption, Allain & Ben Amar [28] obtain the equilibrium equations and associated interface conditions for a biphasic vesicle composed of two spherical caps. Working with the same geometrical assumptions, Allain & Ben Amar [18] develop a model for the budding and the fission of biphasic vesicles under tension.…”

Stability of biphasic vesicles with membrane embedded proteins

“…In contrast to previous researches (Biscari et al, 2004;Allain and Amar, 2004;Markin, 1981;Iglicˇet al, 2004;Foo et al, 2005;Yin et al, 2005), our model considers the coupling between local fraction of protein and membrane mean curvature square. This coupling can be well understood in C.-M. Chen's paper (Chen, 2000), who studied the bending rigidity of lipid membrane with proteins inclusions.…”