Caveolins are a family of integral membrane proteins that are the major components of caveolae membranes and are involved in receptor-independent endocytosis.
In vertebrates, the coding caveolin genes consist of 3 members:
- CAV1
- CAV2 and
- CAV3
which respectively encode the proteins caveolin-1, caveolin-2 and caveolin-3. All three members are membrane proteins with similar structure. Caveolin forms oligomers associated with cholesterol and sphingolipids in specific areas of the cell membrane. Due to the three-dimensional structural peculiarity of these complexes, there is an inward membrane curvature of the cell membrane the caveolae. Caveolins function as scaffolding proteins within caveolar membranes by compartmentalizing and concentrating signaling molecules. Several classes of signaling molecules, including G-protein subunits, receptor and non-receptor tyrosine kinases, endothelial nitric oxide synthase (eNOS), and small GTPases, bind Cav-1 through its "caveolin scaffolding domain".