In biology, caveolae (Latin for little caves, singular: caveola), which are a special type of lipid raft, are small (50–100 nanometer) invaginations of the plasma membrane in many vertebrate cell types, especially in endothelial cells and adipocytes.
These flask-shaped structures are rich in proteins as well as lipids such as cholesterol and sphingolipids and have several functions in signal transduction. They are also believed to play a role in endocytosis, oncogenesis, and the uptake of pathogenic bacteria and certain viruses.
Read more about Caveolae: Caveolins, Caveolar Endocytosis, Other Roles of Caveolae, Inhibitors