INHIBITION OF INTERLEUKIN 1-BETA-CONVERTING ENZYME-MEDIATED APOPTOSISOF MAMMALIAN-CELLS BY BACULOVIRUS IAP

Apoptosis can be a potent weapon against viral infection and consequen tly has selected for viruses carrying antiapoptosis genes, Two baculov irus proteins, IAP and p35, can prevent insect cells from dying in res ponse to infection. p35, which interferes with members of the Ced-3 fa mily of cysteine proteases, can also function in mammalian cells, We i nvestigated the ability of IAP from Orgyia pseudotsugata nuclear polyh edrosis virus to pre, ent death of mammalian cells. IAP was transientl y expressed in mammalian cells and its ability to block cell death cau sed by expression of interleukin-1 beta converting enzyme (ICE), FADD, or the ICE homologues ICH-1 and ICE-Lap3, was investigated, IAP stron gly inhibited ICE- and ICH-1-induced cell death but protected only par tially against death by overexpression of FADD and not at all against death due to enforced ICE-Lap3 expression. These results demonstrate t hat a baculoviral IAP protein can functionally interact with conserved components of the apoptosis machinery in mammalian cells.