Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.36 (caspase-1)
 6,285 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Caspases (ICE/ Ced3 proteases) are a closely related family of cysteine proteases that play a key role in apoptotic cell death. We examined the role of caspases in DNA damage and cell death in response to the mitochondrial inhibitor, antimycin A. LLC-PK1 cells contain caspase activity that was markedly inhibited by cleavage site-based peptide inhibitors of caspases but not by inhibitors of serine, cysteine, aspartate or metalloproteinases. The caspase activity increased within five minutes of exposure to antimycin A, preceding any evidence of DNA damage and cell death. The specific caspase inhibitors. Ac-Tyr-Val-Ala-Asp-aldehyde (inhibitor I) and Ac-Asp-Glu-Val-Asp-aldehyde (inhibitor II) prevented, in a dose dependent manner, antimycin A-induced DNA strand breaks as determined by DNA unwinding assay (residual double stranded DNA in control, 94 +/- 2%; antimycin A alone, 48 +/- 3%; antimycin A + inhibitor I at 50 microM, 93 +/- 2%; antimycin A + inhibitor II at 50 microM, 89 +/- 5%; N = 3 to 4, P < 0.001). These inhibitors also prevented antimycin A-induced DNA fragmentation as determined by agarose gel electrophoresis and by in situ labeling of cell nuclei by the terminal deoxynucleotidyl transferase (TdT) nick end labeling (TUNEL) method. The caspase inhibitors markedly prevented antimycin A-induced cell death in a dose-dependent manner as measured by trypan blue exclusion (control 6 +/- 1%, antimycin A alone 40 +/- 1%, antimycin A + inhibitor I at 50 microM 16 +/- 1%, antimycin A + inhibitor II at 50 microM 16 +/- 1%; N = 4 to 7, P < 0.001). These data indicate that the caspase family of enzymes play an important role in DNA damage and cell death in response to the mitochondrial inhibitor, antimycin A.
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PMID:Role of caspases (ICE/CED 3 proteases) in DNA damage and cell death in response to a mitochondrial inhibitor, antimycin A. 926 99

The cowpox virus (CPV) CrmA and the equivalent rabbitpox virus (RPV) SPI-2 proteins have anti-inflammatory and antiapoptosis activity by virtue of their ability to inhibit caspases, including the interleukin-1beta-converting enzyme (ICE; caspase-1). Infection of LLC-PK1 pig kidney cells with a CPV CrmA mutant, but not with wild-type (wt) CPV, results in the induction of many of the morphological features of apoptosis (C. A. Ray and D. J. Pickup, Virology 217:384-391, 1996). In our study, LLC-PK1 cells infected with CPV delta crmA, but not those infected with wt CPV, showed induction of poly(ADP-ribose) polymerase (PARP)- and lamin A-cleaving activities and processing of the CPP32 (caspase-3) precursor to a mature 18-kDa form. Surprisingly, infection of LLC-PK1 cells with either wt RPV (despite the presence of the SPI-2 protein) or RPV delta SPI-2 resulted in cleavage activity against PARP and lamin A and the appearance of the mature subunit of CPP32/caspase-3. The biotinylated specific peptide inhibitor Ac-Tyr-Val-Lys(biotinyl)-Asp-2,6-dimethylbenzoyloxymethylketone [AcYV(bio)KD-aomk] labeled active caspase subunits of 18, 19, and 21 kDa in extracts from LLC-PK1 cells infected with CPV delta crmA, wt RPV, or RPV delta SPI-2 but not wt CPV. Mixed infection of LLC-PK1 cells with wt RPV and wt CPV gave no PARP-cleaving activity, and all PARP cleavage mediated by SPI-2 and CrmA mutants of RPV and CPV, respectively, could be eliminated by coinfection with wt CPV. These results suggest that the RPV SPI-2 and CPV CrmA proteins are not functionally equivalent and that CrmA, but not SPI-2 protein, can completely prevent apoptosis in LLC-PK1 cells under these conditions.
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PMID:Activation of caspases in pig kidney cells infected with wild-type and CrmA/SPI-2 mutants of cowpox and rabbitpox viruses. 955 31

The Serp2 protein encoded by the leporipoxvirus myxoma virus is essential for full virulence (F. Messud-Petit, J. Gelfi, M. Delverdier, M. F. Amardeilh, R. Py, G. Sutter, and S. Bertagnoli, J. Virol. 72:7830-7839, 1998) and, like crmA of cowpox virus (CPV), is reported to inhibit the interleukin-1beta-converting enzyme (ICE, caspase-1) (F. Petit, S. Bertagnoli, J. Gelfi, F. Fassy, C. Boucraut-Baralon, and A. Milon, J. Virol. 70:5860-5866, 1996). Serp2 and CrmA both contain Asp at the P1 position within the serpin reactive site loop and yet are only 35% identical overall. Serp2 protein was cleaved by ICE but, unlike CrmA, did not form a stable complex with ICE that was detectable by native gel electrophoresis. Attempts to covalently cross-link ICE-serpin inhibitory complexes were successful with CrmA, but no complex between ICE and Serp2 was visible after cross-linking. Purified His10-tagged Serp2 protein was a relatively poor inhibitor of ICE, with a Ki of 80 nM compared to 4 pM for CrmA. Serp2 protein resembled CrmA in that a stable complex with the serine proteinase granzyme B was detectable after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, Serp2 was less effective at inhibiting granzyme B activity (Ki = 420 nM) than CrmA (Ki = 100 nM). Finally, Serp2 was tested for the ability to replace CrmA and inhibit apoptosis in LLC-PK1 cells infected with a CPV recombinant deleted for CrmA but expressing Serp2. Unlike wild-type-CPV-infected cells, apoptosis was readily observed in cells infected with the recombinant virus, as indicated by the induction of both nuclear fragmentation and caspase-mediated cleavage of DEVD-AMC [acetyl-Asp-Glu-Val-Asp-(amino-4-methyl coumarin)]. These results indicate that Serp2 is unable to functionally substitute for CrmA within the context of CPV and that the inhibition spectra for Serp2 and CrmA are distinct.
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PMID:Myxoma virus Serp2 is a weak inhibitor of granzyme B and interleukin-1beta-converting enzyme in vitro and unlike CrmA cannot block apoptosis in cowpox virus-infected cells. 1040 Jul 32