caveosomes

Definition: caveolin-1-containing endosome.

Endocytosis of various endogenous plasma membrane molecules, including signalling receptors, glycosphingolipids and glycosylphosphatidylinositol (GPI)-linked proteins, occurs in the absence of functional clathrin-coated pits.

Most of these molecules are found in biochemically defined lipid rafts, which suggests that at least some clathrin-independent endocytosis may be raft specific or raft mediated.

This is a highly regulated process, and caveolin 1, one of the characteristic protein components of caveolae, might in fact act to slow or inhibit endocytosis. Clathrin-independent uptake to a distinct class of caveolin-1-containing endosome, termed the caveosome, allows different types of endocytic mechanisms to have different functional consequences for the cell.