raku plasmamembraani sissesopistused, mis pungudes raku sisemusse moodustavad pinotsütootilisi vesiikuleid, Caveolae 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.