title: Inhibition of the Caenorhabditis elegans cell-death protease CED-3 by a CED-3 cleavage site in baculovirus p35 protein.
abstract: The baculovirus protein p35 inhibits programmed cell death in such diverse animals as insects, nematodes and mammals. Here we show that p35 protein is a substrate for and inhibitor of the Caenorhabditis elegans cell-death protease CED-3 (refs 6, 7) and a substrate for four CED-3-like vertebrate cysteine protease activities implicated in apoptosis in mammals. A p35 mutation that greatly reduced p35 activity in vitro as a CED-3 substrate and inhibitor abolished p35 activity in vivo in protecting against cell death in C. elegans. Introduction of the CED-3 cleavage site in p35 into the cowpox virus protein crmA, which inhibits mammalian apoptosis but not programmed cell death in C. elegans, caused crmA to block CED-3-mediated cell death. These observations suggest that p35 may prevent programmed cell death in C. elegans and other species by acting as a competitive inhibitor of cysteine proteases.
authors.affiliation: Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.
authors.forename: D
authors.initials: D
authors.lastname: Xue
authors.forename: H R
authors.initials: HR
authors.lastname: Horvitz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D017209:Apoptosis; D016367:Baculoviridae; D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D017173:Caenorhabditis elegans / Q000201:enzymology*; D029742:Caenorhabditis elegans Proteins; D020170:Caspase 1; D020169:Caspases; D003546:Cysteine Endopeptidases / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000378:metabolism*; D017931:DNA Primers; D015801:Helminth Proteins / Q000037:antagonists & inhibitors*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D051379:Mice; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015843:Serpins / Q000378:metabolism; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D015853:Cysteine Proteinase Inhibitors; D017931:DNA Primers; D015801:Helminth Proteins; D051034:Inhibitor of Apoptosis Proteins; D011993:Recombinant Fusion Proteins; D015843:Serpins; D014764:Viral Proteins; C086430:inhibitor of apoptosis, Nucleopolyhedrovirus; C074641:interleukin-1beta-converting enzyme inhibitor; D020169:Caspases; D003546:Cysteine Endopeptidases; C089223:ced-3 protein, C elegans; D020170:Caspase 1