Clustered diffusion of integrins.

We discuss the diffusion of clusters of integrins (and other similar membrane proteins) on a cell membrane with a cortical cytoskeleton. We argue that protein clusters--in contrast with normal oligomers, which are forced to pass through cytoskeletal barriers all at once--should be treated essentially as many-legged random walkers that can pass through a cytoskeletal barrier by putting one leg at a time through the fence. We present the mathematics that should describe the phenomenon, which result in a two-parameter model of diffusion that should apply to any cluster size. We also perform and discuss numerical simulations of the effect in the erythrocyte model system.