title: Spodoptera littoralis caspase-1, a Lepidopteran effector caspase inducible by apoptotic signaling.
abstract: The baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) can successfully infect Spodoptera frugiperda SF9 cells, but in contrast, in Spodoptera littoralis SL2 cells it induces apoptosis aborting the infection. To understand better the mechanism of induction and execution of apoptosis in SL2 cells, we identified and characterized the first Spodoptera littoralis caspase, Sl-caspase-1. Sl-caspase-1 is an effector caspase that cleaves DEVD but not IETD and LEHD substrates, and the caspase-3 inhibitor DQMD-CHO inhibited this activity. It was involved in two apoptotic pathways induced by UV irradiation and virus infection. Moreover processing of Sl-caspase-1 was a determinant factor for baculovirus induction of apoptosis in SL2 cells. Since very little is known on the regulation of expression of Lepidopteran caspases, we studied Sl-caspase-1 expression after exposure to apoptosis stimuli. We found that triggering apoptosis in SL2 cells increased the steady-state level of Sl-caspase-1 without changing the level of sl-caspase-1 mRNA, suggesting that Sl-caspase-1 was post-transcriptionally up regulated. This regulation might occur as an early event in transduction of the apoptotic signal.
authors.affiliation: Entomology Department, Institute of Plant Protection, Agricultural Research Organization, The Volcani Center, POB 6, Bet Dagan, 50250 Israel.
authors.forename: Q
authors.initials: Q
authors.lastname: Liu
authors.forename: Y
authors.initials: Y
authors.lastname: Qi
authors.forename: N
authors.initials: N
authors.lastname: Chejanovsky
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D016367:Baculoviridae; D020170:Caspase 1 / Q000737:chemistry / Q000378:metabolism*; D053470:Caspases, Effector / Q000378:metabolism*; D002460:Cell Line; D004790:Enzyme Induction / Q000187:drug effects / Q000528:radiation effects; D007106:Immune Sera; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000528:radiation effects; D018411:Spodoptera / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D013379:Substrate Specificity / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D007106:Immune Sera; D009842:Oligopeptides; D053470:Caspases, Effector; D020170:Caspase 1