Snapin interacts with the N-terminus of regulator of G protein signaling 7

The N-terminus of regulator of G protein signaling 7 (RGS7) contains a dishevelled/egl-10/pleckstrin (DEP) domain of unknown function. To gain insight into its function, we used yeast two-hybrid analysis to screen a human whole brain cDNA library in order to identify proteins that interact specifically with the N-terminus of human RGS7 (amino acid residues 1-248). From this analysis, we identified snapin, a protein associated with the SNARE complex in neurons, as an interactor with the N-terminus of RGS7. Deletion mutation analysis in yeast demonstrated that the interaction between RGS7 and snapin is specific and is mediated primarily by amino acid residues 1-69 of RGS7 (which contains the proximal portion of the DEP domain). The interaction between RGS7 and snapin was also demonstrated in mammalian cells by coimmunoprecipitation and pull-down assays. Our results suggest that RGS7 could play a role in synaptic vesicle exocytosis through its interaction with snapin.