Potocytosis is a type ofreceptor-mediated endocytosis in which smallmolecules are transported across theplasma membrane of acell. The molecules are transported bycaveolae (rather thanclathrin-coated vesicles) and are deposited directly into thecytosol.[1]
Like other types of receptor-mediated endocytosis, potocytosis typically begins when an extracellularligand binds to areceptor protein on the surface of a cell, thus beginning the formation of anendocytotic vesicle. The ligand is usually of lowmolecular mass (e.g.vitamins), but some larger molecules (such aslipids) can also act as ligands.[1][2]
Lipid rafts in the plasma membrane act as membrane microdomains. They are enriched in cholesterol andsphingolipids and are involved potocytosis as the lateral compartmentalization of molecules.Caveolae are caveolin-1-enriched smooth invaginations found on these lipid rafts that contribute to transportation of molecules.[3] Potocytosis works by taking up material into caveolae at the surface of the cell.Glycosylphosphatidylinositol-anchored class of membrane proteins generate high concentrations of molecules. This may either be by releasing a receptor bound molecule, by converting molecules enzymatically or by releasing them from a carrier protein.[4]