INTERACTION OF PEPTIDES DERIVED FROM THE FAS LIGAND WITH THE FYN-SH3 DOMAIN

Interaction of the widely expressed Pas with its membrane-bound ligand (Fast) leads to rapid cell death via apoptosis. To avoid pathological tissue damage, the activity of Fast requires tight regulation, Here, we report that the Src homology 3 (SH3) domain of Fyn binds to the pro line-rich cytoplasmic region of Fast, Binding of the SH3 domain occurs between amino acid residues 44-71 which contains several potential SH 3 interaction sites, This binding is specific, as SH3 domains of Lck, Grb2 and ras-GAP bind only weakly or not at all. We suggest that Fast activity may be modulated by SH3 domains of the src-like Fyn kinase.