Primary structure and topology of Cav-1. (a) The predicted membrane topology of Cav-1. Two caveolin-1 monomers are shown forming a dimer for simplicity, but about 14-16 monomers normally self-associate to form a single caveolin homo-oligomer (the caveolar assembly unit, akin to the clathrin triskelion). Note that both the amino- and carboxy-terminal domains are oriented towards the cytosolic face of the plasma membrane, with a hairpin loop structure inserted within the membrane bilayer. Modified from Razani et al. . (b) The domains present in Cav-1. Note that the amino-terminal membrane-attachment domain is also called the caveolin scaffolding domain (CSD).