RIP - A NOVEL PROTEIN CONTAINING A DEATH DOMAIN THAT INTERACTS WITH FAS/APO-1 (CD95) IN YEAST AND CAUSES CELL-DEATH

Ligation of the extracellular domain of the cell surface receptor Fas/APO-1 (CD95) elicits a characteristic programmed death response in susceptible cells. Using a genetic selection based on protein-protein interaction in yeast, we have identified two gene products that associate with the intracellular domain of Pas: Pas itself, and a novel 74 kDa protein we have named RIP, for receptor interacting protein. RIP also interacts weakly with the p55 tumor necrosis factor receptor (TNFR1) intracellular domain, but not with a mutant version of Pas corresponding to the murine lpr(cg) mutation. RIP contains an N-terminal region with homology to protein kinases and a C-terminal region containing a cytoplasmic motif (death domain) present in the Pas and TNFR1 intracellular domains. Transient overexpression of RIP causes transfected cells to undergo the morphological changes characteristic of apoptosis. Taken together, these properties indicate that RIP is a novel form of apoptosis-inducing protein.