The baculovirus anti-apoptotic protein Op-IAP does not inhibit Drosophila caspases or apoptosis in Drosophila S2 cells and instead sensitizes S2 cells to virus-induced apoptosis

Casey W. Wright, John C. Means, Taryn Penabaz, Rollie J. Clem

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

The Op-IAP protein from the baculovirus Orgyia pseudotsugata M nucleopolyhedrovirus (OpMNPV) is highly effective at inhibiting apoptosis triggered by a variety of different stimuli in lepidopteran cells as well as in several different mammalian cell types, suggesting that it functions at a highly conserved step in the apoptotic pathway. However, the mechanism by which Op-IAP inhibits apoptosis is unclear. Since some IAP proteins can bind and inhibit caspases, we tested whether Op-IAP could inhibit the activity of caspases from Drosophila melanogaster. We found that recombinant Op-IAP protein was not able to bind or directly inhibit the activity of the Drosophila caspases DRONC, DrICE, or DCP-1 in vitro. In addition, expression of Op-IAP was unable to inhibit apoptosis triggered by either actinomycin D or UV light in D. melanogaster S2 cells. Surprisingly, Op-IAP expression in S2 cells enhanced apoptosis caused by baculovirus infection, but did not cause increased sensitivity to either actinomycin D or UV damage-induced apoptosis. The observation that Op-IAP cannot inhibit these insect caspases suggests that it functions by a mechanism that does not involve direct caspase inhibition.

Original languageEnglish (US)
Pages (from-to)61-71
Number of pages11
JournalVirology
Volume335
Issue number1
DOIs
StatePublished - Apr 25 2005

Keywords

  • Apoptosis
  • Baculovirus
  • Caspase
  • DCP-1
  • DRONC
  • DrICE
  • Drosophila melanogaster
  • IAP protein
  • Op-IAP

ASJC Scopus subject areas

  • Virology

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