Clathrin interacts specifically with amphiphysin and is displaced by dynamin.

Amphiphysin is an SH3 domain protein that has been implicated in synaptic vesicle endocytosis. We have recently cloned a second amphiphysin isoform, Amph2 (sequence submitted to GenBank, Y13380). Proteins capable of forming a complex with amphiphysin were isolated from rat brain by using recombinant GST-Amph2 for binding experiments. As well as interacting with dynamin I, the full-length protein bound to a weaker 180-kDa band. Immunoblotting demonstrated this protein to be clathrin. To address whether this is a direct interaction, the clathrin binding to amphiphysin was reconstituted in vitro with purified proteins. The N-terminal domain of Amph2 is sufficient for clathrin binding. Dynamin, which interacts with the SH3 domain of Amph2, displaces clathrin from the N-terminus. We propose a model that may explain how clathrin and dynamin are recruited to non-overlapping sites of the coated pit.