MOLECULAR-CLONING OF P125(NAP1), A PROTEIN THAT ASSOCIATES WITH AN SH3 DOMAIN OF NCK

Binding proteins to the Src homology 3 (SH3) domains of Nck were scree ned by the use of glutathione S-transferase fusion proteins. Two prote ins of 140 and 125 kDa were detected, both of which associated prefere ntially with the first SH3 domain of Nck. The 125-kDa protein, designa ted as Nap1 for Nck-associated protein 1, was purified and the corresp onding rat cDNA was isolated. The predicted amino acid sequence reveal ed that p125(Nap1) dose not contain any known functional motif but sho ws sequence homology to Hem family gene. Using specific antibodies, p1 25(Nap1) was shown to associate with Nck both in vitro and in intact c ells. Further characterization of p125(Nap1) may clarify the protein-p rotein interaction in the downstream signaling of Nck. (C) 1996 Academ ic Press, Inc.