Dissecting clathrin-coated pits

In vitro cell biology has become an effective way to identify molecules responsible for membrane traffic. We have used this approach to study the assembly and budding of coated pits. So far our system has allowed us to identify a high-affinity binding site for the AP2 subunit on the inside surface of plasma membranes, determine the AP2 domain that links clathrin lattices to the plasma membrane, and purify a molecule that appears to participate in coated-pit budding. These discoveries now need to be verified in vivo.