Potocytosis of small molecules and ions by caveolae.

Potocytosis is an endocytic process for concentrating and taking up small molecules and ions. The vehicle for internalization is the caveolae, a membrane specialization that has previously been implicated in membrane internalization. Within closed caveolae, the glycosylphosphatidylinositol-anchored class of membrane proteins generate high concentrations of small molecules or ions either by releasing receptor-bound species, by enzymatically converting abundant extracellular molecules, or by releasing them from a sequestered, soluble carrier protein. This pathway may also be involved in novel signal-transducing devices.