Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The molecules participating in apoptosis induced by T-2 toxin in human leukemia HL-60 cells were investigated. The rank order of the potency of trichothecene mycotoxins to induce internucleosomal DNA fragmentation was found to be T-2, satratoxin G, roridin A >> diacetoxyscirpenol > baccharin B-5 >> nivalenol, deoxynivalenol, 3-acetyldeoxynivalenol, fusarenon-X, baccharin B-4=vehicle control. Western blot analysis of caspase-3 in T-2-treated cells clearly indicated the appearance of its catalytically active fragment of 17-kDa. Increased caspase-3 activity was also detected by using a fluorogenic substrate, DEVD-AMC. Next, cells exposed to T-2 led to cleavage of PARP from its native 116-kDa form to the 85-kDa product. Moreover, DFF-45/ICAD were cleaved to give a 12.5-kDa fragment via T-2 treatment. T-2 caused the release of cytochrome c from mitochondria into the cytosol. Increased enzymic activity of caspase-9 on LEHD-AMC was shown. These data indicate that T-2-induced apoptosis involves activation of caspase-3 and DFF-40/CAD through cytosolic accumulation of cytochrome c along with caspase-9 activation.
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PMID:Apoptosis induction by T-2 toxin: activation of caspase-9, caspase-3, and DFF-40/CAD through cytosolic release of cytochrome c in HL-60 cells. 1157 12

A hallmark of apoptosis is the fragmentation of nuclear DNA. Although this activity involves the caspase-3-dependent DNAse CAD (caspase-activated DNAse), evidence exists that DNA fragmentation can occur independently of caspase activity. Here we report on the ability of truncated Bid (tBid) to induce the release of a DNAse activity from mitochondria. This DNAse activity was identified by mass spectrometry as endonuclease G, an abundant 30 kDa protein released from mitochondria under apoptotic conditions. No tBid-induced endonuclease G release could be observed in mitochondria from Bcl-2-transgenic mice. The in vivo occurrence of endonuclease G release from mitochondria during apoptosis was confirmed in the liver from mice injected with agonistic anti-Fas antibody and is completely prevented in Bcl-2 transgenic mice. These data indicate that endonuclease G may be involved in CAD-independent DNA fragmentation during cell death pathways in which truncated Bid is generated.
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PMID:Endonuclease G: a mitochondrial protein released in apoptosis and involved in caspase-independent DNA degradation. 1175 61

Apoptosis is a physiological form of cell death that is responsible for the deletion of cells. Epidermal keratinocytes are supposed to be regulated by cell proliferation and cell death leading to structural homeostasis. Psoriatic skin shows marked thickening of the epidermis, suggesting the imbalance of the homeostasis, which might be related to abnormal apoptotic process. We investigated the expression of various apoptosis-related molecules in the psoriatic hyperproliferative epidermis. Real time quantitative RT-PCR analyses revealed that mRNAs of Fas, Bcl-xL, Bax and ICAD (inhibitor of caspase 3-related DNase) of the psoriatic involved epidermis were increased by 4.2-, 2.8-, 2.6- and 5.6-fold, respectively, compared with the uninvolved epidermis. In contrast, Bcl-2 expression in the involved epidermis was one-third suppressed compared with the uninvolved epidermis. No significant difference in the expression of mRNAs of Fas ligand or CAD (caspase 3-related DNase) was detected between the involved and uninvolved epidermis. Western blot analysis and immunohistochemical studies showed compatible results obtained by RT-PCR analyses. Although active caspase 3 was slightly increased in the involved epidermis, apoptotic cells were marginally detected. These results indicate that psoriatic epidermis shows aberrant expression of apoptosis-related molecules representing suppressed apoptotic process, which might be related to characteristic histopathology.
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PMID:Aberrant expression of apoptosis-related molecules in psoriatic epidermis. 1191 6

Apoptotic cell death is characterized by several morphological nuclear changes, such as chromatin condensation and extensive fragmentation of chromosomal DNA. These alterations are primarily triggered through the activation of caspases, which subsequently cleave nuclear substrates. Caspase-3 induces processing of Acinus, which leads to chromatin condensation. DNA fragmentation is dependent on the DNase CAD, which is released from its inhibitor, ICAD, upon cleavage by caspase-3. DNA degradation is also induced by AIF and endonuclease G, which are both released from mitochondria upon death stimuli but do not require prior processing by caspases for their DNase activity. Here we report the identification of a widely expressed helicase designated Helicard, which contains two N-terminal CARD domains and a C-terminal helicase domain. Upon apoptotic stimuli, Helicard is cleaved by caspases, thereby separating the CARD domains from the helicase domain. While Helicard localizes in the cytoplasm, the helicase-containing fragment is found in the nucleus. Helicard accelerates Fas ligand-mediated DNA degradation, whereas a noncleavable or a helicase-dead Helicard mutant does not, implicating Helicard in the nuclear remodeling occurring during apoptosis.
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PMID:Overexpression of Helicard, a CARD-containing helicase cleaved during apoptosis, accelerates DNA degradation. 1201 21

We show here that co-expression of murine CAD with either ICAD-L or ICAD-S in Escherichia coli as well as mammalian cells leads to a functional DFF complex, which after caspase-3 activation releases a nucleolytically active DNase. The chaperone activity of ICAD-S is between one and two orders of magnitude less effective than that of ICAD-L, as deduced from cleavage experiments with different activated recombinant DFF complexes produced in E.coli. With nucleolytically active EGFP fusion proteins of CAD it is demonstrated that co-expression of ICAD-S, which lacks the C-terminal domain of ICAD-L, including the NLS, leads to a homogeneous intracellular distribution of the DNase in transfected cells, whereas co-expression of human or murine ICAD-L variants lacking the NLS leads to exclusion of EGFP-CAD from the nuclei in approximately 50% of cells. These results attribute a particular importance of the NLS in the long isoform of the inhibitor of CAD for nuclear accumulation of the DFF complex in living cells. It is concluded that ICAD-L and ICAD-S in vivo might function as tissue-specific modulators in the regulation of apoptotic DNA degradation by controlling not only the enzymatic activity but also the amount of CAD available in the nuclei of mammalian cells.
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PMID:The effect of ICAD-S on the formation and intracellular distribution of a nucleolytically active caspase-activated DNase. 1296 38

Satratoxins have been recognized as potential immunomodulatory agents in outbreaks of building-related illness. Here we report that satratoxin G-treated human leukemia HL-60 cells underwent apoptosis through the action of caspase-3 which was activated by both caspase-8 and caspase-9. Western blot analysis of caspase-3 in the satratoxin G-treated cells apparently indicated the appearance of a catalytically active fragment of 17 kDa. Increased caspase-3 activity was also detected by using a fluorogenic substrate, DEVD-AMC. Next, exposure to satratoxin G led to cleavage of PARP from its native 116 kDa form to a 85 kDa product. Moreover, DFF-45/ICAD were cleaved into a 12.5 kDa fragment via satratoxin G treatment. Enzymic assay on IETD-AMC revealed that caspase-8 is strongly activated by exposure to satratoxin G while T-2 toxin (T-2) could not activate caspase-8 at an early stage of apoptosis. Furthermore, satratoxin G caused a release of cytochrome c from mitochondria into the cytosol and increased the activity of caspase-9 against LEHD-AMC. These findings indicate that satratoxin G-induced apoptosis involves activation of caspase-3 and DFF-40/CAD through both activation of caspase-8 and cytosolic accumulation of cytochrome c along with activation of caspase-9.
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PMID:Molecular mechanism of satratoxin-induced apoptosis in HL-60 cells: activation of caspase-8 and caspase-9 is involved in activation of caspase-3. 1216 Dec 80

The promyelocytic leukemia protein (PML) is a growth/tumor suppressor essential for induction of apoptosis by diverse apoptotic stimuli. The mechanism by which PML regulates cell death remains unclear. In this study we found that ectopic expression of PML potentiates cell death by apoptosis in the tumor necrosis factor alpha (TNFalpha)-resistant cell line U2OS and other cell lines. Treatment with TNFalpha significantly sensitized these cells to apoptosis in a p53-independent manner. PML/TNFalpha-induced cell death is associated with DNA fragmentation, activation of caspase-3, -7, and -8, and degradation of DNA fragmentation factor/inhibitor of CAD. PML/TNFalpha-induced cell death could be blocked by the caspase-8 inhibitors CrmA and c-FLIP but not by Bcl-2. These findings indicate that this cell death event is initiated through the death receptor-dependent apoptosis pathway. PML is a transcriptional repressor of NF-kappaB by interacting with RelA/p65 and prevents its binding to the cognate enhancer through the C terminus. Coimmunoprecipitation and double-color immunofluorescence staining demonstrated that PML physically interacts with RelA/p65 in vivo and the two proteins colocalized at the endogenous levels. Overexpression of NF-kappaB rescued cell death induced by PML/TNFalpha. Furthermore, PML(-/-) mouse embryo fibroblasts are more resistant to TNFalpha-induced apoptosis. Together this study defines a novel mechanism by which PML induces apoptosis through repression of the NF-kappaB survival pathway.
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PMID:Promyelocytic leukemia protein sensitizes tumor necrosis factor alpha-induced apoptosis by inhibiting the NF-kappaB survival pathway. 1254 Aug 41

DNA fragmentation is a hallmark of cells undergoing apoptosis and is mediated mainly by the caspase-activated DNase (CAD or DNA-fragmentation factor 40 [DFF40]), which is activated when released from its inhibitor protein (ICAD or DFF45) upon apoptosis signals. Here we analyzed the effect of heat shock protein 70 (Hsp70) on CAD activity in T-cell receptor (TCR)-induced apoptosis using a T-cell line (TAg-Jurkat). Overexpression of Hsp70 significantly augmented the apoptotic cell death as well as DNA fragmentation in CD3/CD28- or staurosporine-stimulated cells. Following stimulation of cells with CD3/CD28 or staurosporine, Hsp70 was coprecipitated with free CAD, but not with CAD associated with ICAD. Furthermore, the purified Hsp70 dose-dependently augmented DNA-fragmentation activity of caspase-3-activated CAD in a cell-free system. Peptide-binding domain-deleted Hsp70 could neither bind nor augment its activity, while adenosine triphosphate (ATP)-binding domain-deleted Hsp70 or the peptide-binding domain itself bound CAD and augmented its activity. These results indicate that the the binding of Hsp70 to the activated CAD via the peptide-binding domain augments its activity. Although CAD lost its activity in an hour after being released from ICAD in vitro, its activity was retained after an hour of incubation in the presence of Hsp70, suggesting that Hsp70 may be involved in stabilization of CAD activity. Finally, CAD that had been coprecipitated with Hsp70 from the cell lysate of staurosporine-activated 293T cells induced chromatin DNA fragmentation and its activity was not inhibited by ICAD. These results suggest that Hsp70 binds free CAD in TCR-stimulated T cells to stabilize and augment its activity.
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PMID:Heat shock protein 70 binds caspase-activated DNase and enhances its activity in TCR-stimulated T cells. 1273 67

We previously isolated a 34-kDa nuclease (AN34) from apoptotic human leukemia cells. Here, we identify AN34 as an N-terminally truncated form of human AP endonuclease (Ape1) lacking residues 1-35 (delta35-Ape1). Although Ape1 has hitherto been considered specific for damaged DNA (specific to AP site), recombinant AN34 (delta35-Ape1) possesses significant endonuclease activity on undamaged (normal) DNA and in chromatin. AN34 also displays enhanced 3'-5' exonuclease activity. Caspase-3 activates AN34 in a cell-free system, although caspase-3 cannot cleave Ape1 directly in vitro. We also found that Ape1 itself preferentially cleaves damaged chromatin DNA isolated from cells treated with apoptotic stimuli and that silencing of Ape1 expression decreases apoptotic DNA fragmentation in DFF40/CAD-deficient cells. Thus, we propose that AN34 and Ape1 participate in the process of chromatin fragmentation during apoptosis.
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PMID:Human apurinic/apyrimidinic endonuclease (Ape1) and its N-terminal truncated form (AN34) are involved in DNA fragmentation during apoptosis. 1284 73

During apoptosis (also called programmed cell death), the chromatin condenses and the DNA is cleaved into oligonucleosomal fragments. Caspases are believed to play a major role in nuclear apoptosis. However, the relation between dismantling of nuclear pores, disruption of the nucleocytoplasmic barrier, and nuclear entry of caspases is unclear. We have analyzed nuclear import of the green fluorescent protein fused to a nuclear localization signal (GFP-NLS) in tissue culture cells undergoing apoptosis. Decreased nuclear accumulation of GFP-NLS could be detected at the onset of nuclear apoptosis manifested as dramatic condensation and redistribution of chromatin toward the nuclear periphery. At this step, dismantling of nuclear pores was already evident as indicated by proteolysis of the nuclear pore membrane protein POM121. Thus, disruption of nuclear compartmentalization correlated with early signs of nuclear pore damage. Both these events clearly preceded massive DNA fragmentation, detected by TUNEL assay. Furthermore, we show that in apoptotic cells, POM121 is specifically cleaved at aspartate-531 in its large C-terminal portion by a caspase-3-dependent mechanism. Cleavage of the C-terminal portion of POM121, which is adjoining the nuclear pore complex, is likely to disrupt interactions with other nuclear pore proteins affecting the stability of the pore complex. A temporal correlation of apoptotic events supports a model where caspase-dependent disassembly of nuclear pores and disruption of the nucleocytoplasmic barrier paves the way for nuclear entry of caspases and subsequent activation of CAD-mediated DNA fragmentation.
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PMID:Correlation between nucleocytoplasmic transport and caspase-3-dependent dismantling of nuclear pores during apoptosis. 1472 72


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