THE SH3 DOMAIN OF AMPHIPHYSIN BINDS THE PROLINE-RICH DOMAIN OF DYNAMIN AT A SINGLE-SITE THAT DEFINES A NEW SH3 BINDING CONSENSUS SEQUENCE

Amphiphysin is an SH3 domain-containing neuronal protein that is highl y concentrated in nerve terminals where it interacts via its SH3 domai n with dynamin I, a GTPase implicated in synaptic vesicle endocytosis. We show here that the SH3 domain of amphiphysin, but not a mutant SH3 domain, bound with high affinity to a single site in the long proline -rich region of human dynamin I, that this site was distinct from the binding sites for other SH3 domains, and that the mutation of two adja cent amino acids in dynamin I was sufficient to abolish binding. The d ynamin I sequence critically required for amphiphysin binding (PSRPNR) fits in the novel SH3 binding consensus identified for the SH3 domain of amphiphysin via a combinatorial peptide library approach: PXRPXR(H )R(H). Our data demonstrate that the long proline-rich stretch present in dynamin I contained multiple SH3 domain binding sites that recogni ze interacting proteins with high specificity.