Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.22.56 (caspase-3)
 35,750 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The major mechanism of cytotoxic lymphocyte killing involves the directed release of granules containing perforin and a number of proteases onto the target cell membrane. One of these proteases, granzyme B, has an unusual substrate site preference for Asp residues, a property that it shares with members of the emerging interleukin-1beta-converting enzyme (ICE)/CED-3 family of proteases. Here we show that granzyme B is sufficient to reproduce rapidly all of the key features of apoptosis, including the degradation of several protein substrates, when introduced into Jurkat cell-free extracts. Granzyme B-induced apoptosis was neutralized by a tetrapeptide inhibitor of the ICE/CED-3 family protease, CPP32, whereas a similar inhibitor of ICE had no effect. Granzyme B was found to convert CPP32, but not ICE, to its active form by cleaving between the large and small subunits of the CPP32 proenzyme, resulting in removal of the prodomain via an autocatalytic step. The cowpox virus protein CrmA, a known inhibitor of ICE family proteases as well as granzyme B, inhibited granzyme B-mediated CPP32 processing and apoptosis. These data demonstrate that CPP32 activation is a key event during apoptosis initiated by granzyme B.
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PMID:The cytotoxic cell protease granzyme B initiates apoptosis in a cell-free system by proteolytic processing and activation of the ICE/CED-3 family protease, CPP32, via a novel two-step mechanism. 866 48

Cysteine proteases related to mammalian interleukin-1 beta converting enzyme (ICE) and to its Caenorhabditis elegans homologue, CED-3, play a critical role in the biochemical events that culminate in apoptosis. We have determined the three-dimensional structure of a complex of the human CED-3 homologue CPP32/apopain with a potent tetrapeptide-aldehyde inhibitor. The protein resembles ICE in overall structure, but its S4 subsite is strikingly different in size and chemical composition. These differences account for the variation in specificity between the ICE- and CED-3-related proteases and enable the design of specific inhibitors that can probe the physiological functions of the proteins and disease states with which they are associated.
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PMID:The three-dimensional structure of apopain/CPP32, a key mediator of apoptosis. 867 6

CPP32, which is most closely related to CED-3 in the apoptotic protease in C. elegance, is activated during apoptosis induced by anti-Fas and TNF. Since processing of CPP32 is important for the activation, we examined the effects of protease inhibitors on CPP32-like activity in the TNF-treated U937 cells. Unexpectedly, proteasome inhibitors (at 5 microM) such as Z-LLnV, Z-LLL, and lactacystin enhanced CPP32-like activity, Ac-DEVD-MCA degrading activity, in the TNF-treated U937 cells in 3 hr, but E64d, cysteine protease inhibitor, did not. These proteasome inhibitors alone did not enhance CPP32-like activity in the untreated U937 cells under the condition used. The proteasome seems to protect the cells from apoptosis by degrading CPP32-like protease or its processing enzyme.
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PMID:Enhancement of CPP32-like activity in the TNF-treated U937 cells by the proteasome inhibitors. 869 36

Apoptosis has recently been recognized as a mode of cell death in Huntington disease (HD). Apopain, a human counterpart of the nematode cysteine protease death-gene product, CED-3, has a key role in proteolytic events leading to apoptosis. Here we show that apoptotic extracts and apopain itself specifically cleave the HD gene product, huntingtin. The rate of cleavage increases with the length of the huntingtin polyglutamine tract, providing an explanation for the gain-of-function associated with CAG expansion. Our results show that huntingtin is cleaved by cysteine proteases and suggest that HD might be a disorder of inappropriate apoptosis.
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PMID:Cleavage of huntingtin by apopain, a proapoptotic cysteine protease, is modulated by the polyglutamine tract. 869 24

Interleukin-1 beta converting enzyme (ICE) defines a new class of mammalian cysteine protease that shares strong homology with the Caenorhabditis elegans death gene ced-3. Both ICE and CED-3, when introduced into cultured cells, induce apoptosis, indicating that this type of cysteine protease may play an important role in the process of programmed cell death. Here, we report the cloning of a mouse and rat gene encoding a novel cysteine protease. The putative proteins encoded by these cDNAs contain the conserved sequence (QACRG) necessary for covalent linkage to the substrate as well as the three amino acids responsible for substrate binding and catalysis in ICE. Amino acid sequence analysis indicates that this rodent cysteine protease is the homolog of human CPP32 beta. Mouse CPP32 beta mRNA is highly expressed in spleen, and to a lesser degree in brain, lung, liver, and kidney. The mouse CPP32 beta genomic locus spans a region of approximately 20 kb, including seven exons and six introns. Mouse interspecific backcross mapping allowed localization of CPP32 beta to the central region of mouse chromosome 8, linked to Scvr, Lpl, Jund1 and Mlr.
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PMID:Molecular characterization of mouse and rat CPP32 beta gene encoding a cysteine protease resembling interleukin-1 beta converting enzyme and CED-3. 876 Dec 96

Members of the ICE/CED-3 protease family appear to play an essential role in programmed cell death process. In this paper the chromosomal localization of the human genes CPP32, Mch2, Mch3 and Ich-1 is reported, obtained by Radiation Hybrid Mapping. CPP32 was assigned to chromosome 4q33-q35.1, Mch2 to chromosome 4q25-q26, Mch3 to chromosome 10q25.1-q25.2 and Ich-1 to chromosome 7q35. Ich-1 was found to map very close to the marker WI-9353. The possible overlapping of the two independent locus assignments is considered. The genomic distribution of these genes is discussed, with particular reference to the co-location with some human genetic diseases all characterized by autosomal dominant inheritance and by similar malformative features.
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PMID:Chromosomal localization of the human genes, CPP32, Mch2, Mch3, and Ich-1, involved in cellular apoptosis. 878 Jul 21

The ICE/CED-3 family of proteases has been implicated in playing a fundamental role in programmed cell death. Bcl-2 protein represses a number of apoptotic death programs, but the biochemical mechanism of its action is not known. We investigated the activation of ICE/CED-3 proteases induced by three apoptotic stimuli (staurosporine, ceramide, and serum withdrawal) in the neuronal cell line GT1-7 and in cells overexpressing Bcl-2. Rapid activation of a 17 kDa subunit of an activated member of the ICE/CED-3 family is demonstrated by affinity-labeling GT1-7 extracts from apoptotic controls cells with a biotinylated ICE/CED-3 inhibitor. This activation corresponds to an increased ICE/CED-3-like protease activity in extracts measured by a fluorogenic substrate assay. In a cell-free system, these extracts induce apoptotic morphological changes in intact nuclei. All three activities are readily inhibited by treatment of control extracts with ICE/CED-3-like protease inhibitors. Overexpressed Bcl-2 inhibits the activation of the 17 kDa protein, the ICE/CED-3-like protease activity in the fluorogenic assay, and the induction of apoptotic morphological changes in HeLa nuclei in the cell-free system, similar to results obtained with ICE/CED-3 protease inhibitors. At the mRNA level, overexpression of Bcl-2 did not alter expression of five members of the ICE/CED-3 family: CPP32, ICE, Mch 2, Nedd 2, and TX. Overexpression of Bcl-2 prevented the apoptosis-induced processing of pro-Nedd 2 to the cleaved form. These data suggest that Bcl-2 participates upstream from the function of ICE/CED-3 proteases and may inhibit apoptosis by preventing the post-translational activation of ICE/CED-3 proteases.
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PMID:Bcl-2 expression in neural cells blocks activation of ICE/CED-3 family proteases during apoptosis. 879 21

Cytotoxic T lymphocytes (CTLs) and natural killers (NK) cells provide immune surveillance against viruses and neoplasms, and play a central role in the pathogenesis of autoimmune disease, AIDS and graft rejection. Thus, it is important to understand the precise molecular mechanism(s) whereby cytotoxic lymphocytes destroy susceptible target cells. Granule-mediated cytotoxicity requires a combination of both perforin and granzyme B. Perforin polymerizes to form transmembrane channels and presumably allows granzyme B access to target cell substrates, which until recently, were unknown. One clue to the identity of the physiological substrate(s) activated by granzyme B comes from its unusual specificity for cleaving synthetic substrates after aspartate residues. Members of the ICE/CED-3 family of cysteine proteases are prime candidates as they are important apoptotic effectors and are expressed as zymogens, which can be processed to form active heterodimeric enzymes after cleavage at specific aspartate residues. Previous studies have shown that granzyme B proteolytically activates the cell death effector Yama/CPP32/apopain (referred to here as Yama). Here we report that granzyme B also activates ICE-LAP3/Mch3/CMH-1 (referred to here as ICE-LAP3), which, along with Yama and Mch2, forms a subset of the ICE/CED-3 family of cysteine proteases most closely related to the Caenorhabditis elegans cell death gene, CED-3. Importantly, Jurkat T cells incubated with granzyme B and a sublytic concentration of perforin undergo apoptosis, which is preceded by the activation of endogenous ICE-LAP3. Thus, we propose that granzyme B mediates apoptosis by directly engaging the target cell's death effector machinery, which is probably composed of an arsenal of intracellular, CED-3-like cysteine proteases.
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PMID:Cytotoxic T-cell-derived granzyme B activates the apoptotic protease ICE-LAP3. 880 7

Phosphatidylserine (PS), a lipid normally confined to the inner leaflet of the plasma membrane, is exported to the outer plasma membrane leaflet during apoptosis to serve as a trigger for recognition of apoptotic cells by phagocytes. The mechanism of PS export during apoptosis is not known nor is it clear whether the nuclear changes that typify apoptosis contribute in any way to this event. Here, we demonstrate that ligation of the CD95 (Fas/APO-1) molecule on Jurkat cytoplasts induces dramatic PS externalization similar to that observed during apoptosis of intact cells. Apoptosis of both cells and cytoplasts was associated with proteolytic processing of CPP32, a member of the interleukin-1beta converting enzyme (ICE)/CED-3 protease family, to its active form. Fodrin, a component of the cortical cytoskeleton, also underwent proteolytic cleavage during apoptosis of both cytoplasts and intact cells. Strikingly, CPP32 activation, fodrin proteolysis, and PS externalization were all inhibited in the presence of peptide inhibitors of ICE/CED-3 family proteases. These data provide strong support for the notion that the cell death machinery is extranuclear and is likely to be comprised of one or more members of the ICE/CED-3 family and that activation of this machinery does not require nuclear participation.
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PMID:Phosphatidylserine externalization during CD95-induced apoptosis of cells and cytoplasts requires ICE/CED-3 protease activity. 891 May 16

Programmed cell death (apoptosis) is a prominent feature of the development of the immune and nervous systems. The identification of the Caenorhabditis elegans cell death gene, ced-3, as a prototype of the interleukin-1beta converting enzyme (ICE) protease family has led to extensive evidence implicating these enzymes in apoptosis. Among the ten or more members of the ICE protease family, CPP32/yama/apopain exhibits the highest similarity to CED-3 in both sequence homology and substrate specificity. To analyse its function in vivo, we generated CPP32-deficient mice by homologous recombination. These mice, born at a frequency lower than expected by mendelian genetics, were smaller than their littermates and died at 1-3 weeks of age. Although their thymocytes retained normal susceptibility to various apoptotic stimuli, brain development in CPP32-deficient mice was profoundly affected, and discernible by embryonic day 12, resulting in a variety of hyperplasias and disorganized cell deployment. These supernumerary cells were postmitotic and terminally differentiated by the postnatal stage. Pyknotic clusters at sites of major morphogenetic change during normal brain development were not observed in the mutant embryos, indicating decreased apoptosis in the absence of CPP32. Thus CPP32 is shown to play a critical role during morphogenetic cell death in the mammalian brain.
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PMID:Decreased apoptosis in the brain and premature lethality in CPP32-deficient mice. 893 24


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