Flow-induced transport of a membrane protein on vesicle surface

Biomembrane is mainly constructed by phospholipid bilayer and plays as an interface between cell/organelle and cellular environment. Each lipid can freely move in the membrane surface, and lipid-bilayer acts as a fluid membrane. Such fluidity is important for transport of membrane proteins, which are often responsible for biological functions, and many researchers have been investigating the motion of membrane protein. Due to small size of membrane proteins, diffusion phenomena have been mainly discussed and flow-induced transport has not been featured.

In this study, we investigated flow-induced transport of a membrane protein using a dissipative particle dynamics. Especially, we analyzed motions of a membrane protein located on a vesicle surface. Exerted by shear flow, the membrane protein was gradually moved towards the vorticity axis with a random walk, and it tends to concentrate on the vorticity axis. To see the mechanism of the protein concentration, we changed shear strength and protein size, and we found the protein concentration was occurred by force balance between the drag force and thermodynamic diffusion force, and it can be summarized by Peclet number even in the nano-scale transport.