Dynamin binds to SH3 domains of phospholipase Cγ and GRB-2

Src homology 3 (SH3) domains are found in a variety of proteins that are involved in signal transduction or represent components of the cytoskeleton. These domains are thought to serve as modules that mediate specific protein- protein interactions that include proline-rich sequences on the target protein. We have identified proteins of 110, 80, 65, and 43 kDa in human embryonic fibroblasts that bind specifically to the SH3 domain of phospholipase Cγ, a primary substrate of receptor tyrosine kinases, and characterized the 110-kDa band as the microtubule-activated GTPase dynamin. In addition, dynamin binds the son of sevenless adaptor protein GRB-2 with even higher affinity. This interaction does not require the dynamin GTPase function and involves a proline-rich target sequence between residues 812 and 820 of dynamin.