Convective flow effects in receptor-mediated endocytosis (Q1101363)

Receptors for low density lipoprotein (LDL) and other macromolecules are known to aggregate in specialized cell surface structures called coated pits prior to being internalized by the cell when the coated pit closes off. In this paper, the implications for receptor aggregation of factors other than diffusion which influence the movement of receptors toward coated pits are investigated. The effect of a radial flow toward coated pits in the presence of nonrandom insertion of receptors is considered. The corresponding effect of a transverse flow in the plane of the cell membrane under uniform insertion is estimated. It is shown that for physiologically plausible flow values, the radial flow has a negligible effect on the trapping rate of receptors in coated pits, while a transverse flow may significantly reduce the trapping time, provided the coated pit is not swept along in the flow.