| In this report , we show that p 53 inducible RING finger protein ( p53RFP ) , a p 53 inducible E 3 ubiquitin ligase , induces p 53 dependent but caspase independent apoptosis . p53RFP contains an N terminal RING IBR RING domain and an uncharacterized , evolutionally highly conserved C terminal domain . p53RFP interacts with E 2 ubiquitin conjugating enzymes UbcH 7 and UbcH 8 but not with UbcH 5 , and this interaction is mediated through the RING IBR RING domain of p53RFP . ^^^ |