Computer simulations of vesicle fission induced by external amphipathic inclusions.

Fission is an important biological phenomenon to maintain normal functions of cells, but its mechanism is not quite clear. In this paper, the fission behaviors of a two-component lipid vesicle induced by external amphipathic inclusions are studied by the dissipative particle dynamics method. We find that the fission of the lipid domain the in a spherical vesicle will occur only when the concentration of amphipathic inclusions is beyond a threshold concentration. It reveals that this kind of fission is induced by the combination of the domain's line tension and the asymmetric distribution of the amphipathic inclusions in the membrane's inner and outer leaflets. Furthermore, we also find that the fission behaviors are influenced by the area-to-volume ratio of vesicles and the structure characters of amphipathic inclusions (e.g., chain length and rigidity). Especially, the chain length and rigidity of amphipathic inclusions have complicated effects on the vesicle fission. With the variation of these factors, the fission process will be accelerated or delayed. The present study is helpful to understand the possible fission mechanism of lipid bilayers with embedded proteins.