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)

Interleukin-1beta-converting enzyme (ICE)/ced-3 family proteases play key roles in apoptosis. However, cellular substrates for ICE family proteases involved in apoptosis are not well understood. We previously showed that actin is cleaved in vitro by an ICE family protease, distinct from ICE itself, which is activated during VP-16-induced apoptosis. In this report, we demonstrate that the actin-cleaving ICE-family protease in the apoptotic cell extract is the activated CPP-32/apopain. CPP-32 effectively cleaves actin protein to 15 kDa and 31 kDa fragments. Studies with an antibody raised against Gly-Gln-Val-Ile-Thr peptide, the N-terminal sequence of the cleaved 15 kDa actin fragment, showed that actin is also cleaved in vivo during the development of apoptosis. Moreover, Benzyloxycarbonyl-Glu-Val-Asp-CH2OC(O)-2,6,-dichlorobenzene (Z-EVD-CH2-DCB), a selective inhibitor of CPP-32(-like) protease, efficiently inhibited the cleavage of actin and the apoptosis of VP-16-treated U937 cells. Our present results indicate that actin is the substrate of CPP-32/apopain(-like) protease both in vitro and in vivo and suggest the role of actin in the control of cell growth and apoptosis.
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PMID:Actin cleavage by CPP-32/apopain during the development of apoptosis. 907 Jun 48

The interleukin-1 beta converting enzyme (ICE) family of cysteine proteases has been implicated in apoptosis. This study tested the effects of a novel pan-ICE family inhibitor, bocaspartyl(OMe)-fluoromethylketone (boc-Asp-CH2F), against low potassium-induced apoptosis of cultured rat cerebellar granule neurons (CGN). A single application of this cell-permeant compound (20 microM) inhibited apoptotic cell death up to 48 h. Classical apoptotic changes were monitored by fluorescence microscopy, DNA fragmentation and scanning electron microscopy (SEM). A control peptidic fluoromethylketone (boc-Thr-CH2F), and inhibitors to calpain (Ac-Leu-Leu-norleucinal), cathepsin B (Z-Phe-Ala-CH2F), and CPP32-like proteases (Z-DEVD-CH2F), failed to prevent apoptotic death. An 35S-methionine incorporation assay verified that, unlike cycloheximide, boc-Asp-CH2F did not inhibit protein synthesis, hence excluding this as a rescuing mechanism. Although ICE was not detected by northern blot analysis, both CPP32 and Nedd2 expression were found to increase during apoptosis. Kinetic assays with cell extracts from boc-Asp-CH2F-treated neurons measured reduced rates of cleavage for DEVD-pNA and LEVD-pNA. At present, ICE-like proteases remain viable candidates for mediating neuronal death.
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PMID:Inhibition of the interleukin-1 beta converting enzyme family rescues neurons from apoptotic death. 915 87

MEK kinases (MEKKs) are serine-threonine kinases that regulate sequential protein phosphorylation pathways involving mitogen-activated protein kinases (MAPKs), including members of the Jun kinase (JNK) family. MEKK1 is a 196 kDa protein that when cleaved by caspase-3-like proteases generates an active COOH-terminal kinase domain. Expression of the MEKK1 kinase domain is sufficient to induce apoptosis. Mutation of MEKK1 to prevent its proteolytic cleavage protects cells from MEKK1-mediated cell death even though the JNK pathway is still activated, indicating that JNK activation is not sufficient to induce cell death. The inducible acute expression at modest levels of the activated MEKK1 kinase domain can be used to potentiate the apoptotic response to low dose ultraviolet irradiation and cisplatin. Similarly, in L929 fibrosarcoma cells inducible acute expression of the kinase domain of MEKK1 markedly increased the cell death response to tumor necrosis factor alpha (TNF alpha). The findings demonstrate that acute expression of an active form of MEKK1 can potentiate the cell death response to external stress stimuli. Manipulation of MEKK1 proteolysis and its regulation of signal pathways involved in apoptosis has significant potential for anticancer therapies when used in combination with therapeutic agents at doses that alone have little or modest effects on cell viability.
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PMID:Potentiation of apoptosis by low dose stress stimuli in cells expressing activated MEK kinase 1. 939 40

Homeostasis of cell numbers is achieved by balancing the proliferative and death states of cells. Proper regulation in a cell requires an accurate coordination between these two processes. Indeed, dysregulation of cell cycle progression is essential for the initiation of apoptosis. Retinoblastoma protein (RB) is an important tumor suppressor and a cell cycle regulator. Most recent studies suggest that RB also plays a regulatory role in the process of apoptosis. During the onset of apoptosis, the hyperphosphorylated form of RB (p120/hyper) is converted to a hypophosphorylated form (p115/hypo), which is mediated by a specific protein-serine/ threonine phosphatase activity. Accompanied by the internucleosomal fragmentation of DNA, the newly formed p115/hypo/RB is immediately cleaved by a protease that has properties of the caspase family. During apoptosis, RB is also cleaved in its carboxyl terminus by a caspase-3-like activity. By contrast, the unphosphorylated form of RB (p110/unphos) remains uncleaved during apoptosis. Further studies suggest that p110/unphos/RB functions as an inhibitor of apoptosis. Therefore, regulation of the RB proteolytic activities and consequent RB levels is important for the determination of cellular fate.
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PMID:RB and apoptotic cell death. 954 37

p21-activated protein kinase gamma-PAK (Pak2, PAK I) is cleaved by CPP32 (caspase 3) during apoptosis and plays a key role in regulation of cell death. In vitro, CPP32 cleaves recombinant gamma-PAK into two peptides; 1-212 contains the majority of the regulatory domain whereas 213-524 contains 34 amino acids of the regulatory domain plus the entire catalytic domain. Following cleavage, both peptides become autophosphorylated with [gamma-32P]ATP. Peptide 1-212 migrates at 27,000 daltons (p27) upon SDS-polyacrylamide gel electrophoresis and at 32,000 daltons following autophosphorylation on serine (p27P); the catalytic subunit migrates at 34,000 daltons (p34) before and after autophosphorylation on threonine. Following caspase cleavage, a significant lag (approximately 5 min) is observed before autophosphorylation and activity are detected. When gamma-PAK is autophosphorylated with ATP(Mg) alone and then cleaved, only p27 contains phosphate, and the enzyme is inactive with exogenous substrate. After autophosphorylation of gamma-PAK in the presence of Cdc42(GTPgammaS) or histone 4, both cleavage products contain phosphate and gamma-PAK is catalytically active. Mutation of the conserved Thr-402 to alanine greatly reduces autophosphorylation and protein kinase activity following cleavage. Thus activation of gamma-PAK via cleavage by CPP32 is a two-step mechanism wherein autophosphorylation of the regulatory domain is a priming step, and activation coincides with autophosphorylation of the catalytic domain.
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PMID:Cleavage and activation of p21-activated protein kinase gamma-PAK by CPP32 (caspase 3). Effects of autophosphorylation on activity. 978 69

1. Cultured cerebellar granule neurons maintained in medium containing 26 mM potassium (high K+ or HK+) undergo cell death when switched to medium with 5 mM potassium (low K+ or LK+). This low K(+)-induced cell death has typical features of apoptosis. The intracellular signaling pathway of low K(+)-induced apoptosis has been investigated. 2. Cerebellar granule neurons become committed to undergo apoptosis between 2 and 5 h after K+ deprivation, judging from the inability of high K+ to rescue them after this time. Although the levels of most mRNAs decrease markedly concomitant with commitment, expression of c-jun mRNA increases 2-3 h after K+ deprivation. Among the family of caspases, a caspase-3-like protease is activated within 4 h of lowering the K+ concentration. A caspase-1-like protease is also activated within 2 h of K+ deprivation. 3. Inhibition of phosphatidylinositol 3-kinase (PI3-K) activity by LY294002 or wortmannin also induces apoptosis in cerebellar granule neurons. The intracellular signaling pathway of LY294002-induced apoptosis has been investigated. The activity of c-Jun N-terminal kinase (JNK) increases 8 h after addition of LY294002 to high K+ medium or low K+ medium containing BDNF. Expression of c-Jun protein also increases almost simultaneously. 4. The low K(+)-induced apoptosis of cerebellar granule neurons is prevented by high K+ (membrane depolarization by high K+), BDNF, IGF-1, bFGF or cAMP. The intracellular signaling pathways by which these agents prevent low K(+)-induced apoptosis have been investigated. Agents other than cAMP prevent apoptosis through PI3-K and a Ser/Thr kinase, Akt/PKB. The survival-promoting effect of cAMP does not depend on the PI3-K-Akt pathway.
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PMID:[Apoptosis-inducing and -preventing signal transduction pathways in cultured cerebellar granule neurons]. 1008 75

The hormonally active form of vitamin D3, 1,25-dihydroxyvitamin D3, and its two analogues, EB 1089 and CB 1093, are novel putative anticancer agents with an interesting profile of induction of growth inhibition, differentiation, and apoptosis in tumor cells. To study the signaling pathways mediating these events, we used two human breast cancer cell lines: MCF-7 cells, expressing a wild-type p53 tumor suppressor protein, and T47D cells, lacking a functional p53. Vitamin D compounds induced a growth arrest followed by apoptosis in both cell lines at concentrations ranging from 1 to 100 nM, indicating that p53 is not necessary for growth-inhibitory effects induced by vitamin D compounds. Surprisingly, apoptosis induced by these compounds occurred also independently of known caspases. Inhibition of caspase activation by overexpression of a cowpox-derived caspase inhibitor CrmA or by addition of inhibitory peptides acetyl-Asp-Glu-Val-Asp-aldehyde (200 microM), acetyl-Ile-Glu-Thr-Asp-aldehyde (50 microM), and Z-Val-Ala-D,L-Asp-fluoromethylketone (1 microM) showed no effect on the induction of growth arrest or apoptosis by vitamin D compounds under assay conditions in which apoptosis induced by TNF or staurosporine was effectively inhibited. Moreover, overexpression of caspase-3 in MCF-7 cells had no sensitizing effect to vitamin D compounds, and neither caspase-3-like protease activity nor cleavage of a caspase substrate poly(ADP)ribose polymerase was detected in lysates from apoptotic cells following the treatment with these compounds. Contrary to CrmA, overexpression of an antiapoptotic protein Bcl-2 in MCF-7 cells conferred a nearly complete protection from apoptosis induced by vitamin D compounds. Taken together, these data indicate that vitamin D compounds induce apoptosis via a novel caspase- and p53-independent pathway that can be inhibited by Bcl-2. This may prove useful in the treatment of tumors that are resistant to therapeutic agents that are dependent on the activation of p53 and/or caspases.
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PMID:Apoptosis induced by vitamin D compounds in breast cancer cells is inhibited by Bcl-2 but does not involve known caspases or p53. 1051 95

The mechanism of apoptosis induced by 2-chloro-2'-deoxyadenosine (2CdA) in human leukemia cell line MOLT-4 was investigated. 2CdA induced increases of 3'-OH ends of genomic DNA, ladder-like DNA fragmentation and phosphatidylserine translocation to the outer membrane, which are apoptotic characteristics. These apoptotic phenomena induced by 2CdA were inhibited by cycloheximide (CHX; a protein synthesis inhibitor), deoxycytidine (dC; a substrate of deoxycytidine kinase), acetyl Ile-Glu-Thr-Asp aldehyde (Ac-IETD-CHO; a caspase-8 inhibitor) and acetyl Asp-Glu-Val-Asp aldehyde (Ac-DEVD-CHO; a caspase-3 inhibitor). The protein synthesis-dependent expression of Fas and Fas ligand (Fas-L) was detected by treatment with 2CdA. The proteolytic processing of procaspases-8 and -3 to produce active fragments, caspases-8 (p18) and -3 (p17), respectively, was observed after treatment with 2CdA, and suppressed by cycloheximide. Increases in the activities of caspases-8 and -3 were observed after 2CdA treatment. Their activation was also dependent on protein synthesis. These results indicated that 2CdA-induced apoptosis was triggered by phosphorylation of 2CdA followed by the protein synthesis-dependent expression of Fas and Fas-L and activation of caspases-8 and -3.
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PMID:2-Chloro-2'-deoxyadenosine induces apoptosis through the Fas/Fas ligand pathway in human leukemia cell line MOLT-4. 1067 48

Specific inhibitors of serine/threonine phosphatases like okadaic acid can induce apoptotic cell death in the pancreatic beta cell line HIT. Cultivation in stepwise increased concentrations of okadaic acid enabled the isolation of HIT100R cells which proliferate at 100 nM okadaic acid (8 - 10 times the initially lethal concentration). These two cell lines were used to characterize the events triggered by okadaic acid that led to apoptosis. Biochemical markers, e.g. cytochrome c release from mitochondria and increase of caspase-3-like activity, revealed that induction of apoptosis by 100 nM okadaic acid in parental HIT cells started with the release of cytochrome c. In HIT100R cells 500 nM okadaic acid were necessary to induce alterations comparable to those observed with 100 nM okadaic acid in non-resistant HIT cells. In contrast to okadaic acid, the potency of the structurally different phosphatase inhibitor cantharidic acid to induce cytochrome c release, increase of caspase-3-like activity and DNA fragmentation was comparable in HIT and HIT100R cells. Thus, no cross-resistance between these phosphatase inhibitors seemed to exist. Phosphatase activity in extracts from HIT and HIT100R cells did not differ in its total amount or in its sensitivity for okadaic acid. Since higher concentrations of okadaic acid were needed to induce apoptosis in HIT100R cells, a compromised intracellular accumulation of the toxin appeared likely. Functional and structural analysis revealed that this was achieved by the development of the multidrug resistance phenotype in HIT100R cells. The underlying mechanism appeared to be the enhanced expression of the pgp1 but not the pgp2 gene.
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PMID:Hamster pancreatic beta cell lines with altered sensitivity towards apoptotic signalling by phosphatase inhibitors. 1068 93

Calcium overload is suggested to play a fundamental role in the process of rod apoptosis in chemical-induced and inherited retinal degenerations. However, this hypothesis has not been tested directly. We developed an in vitro model utilizing isolated rat retinas to determine the mechanisms underlying Ca(2+)- and/or Pb(2+)-induced retinal degeneration. Confocal microscopy, histological, and biochemical studies established that the elevated [Ca(2+)] and/or [Pb(2+)] were localized to photoreceptors and produced rod-selective apoptosis. Ca(2+) and/or Pb(2+) induced mitochondrial depolarization, swelling, and cytochrome c release. Subsequently caspase-9 and caspase-3 were sequentially activated. Caspase-7 and caspase-8 were not activated. The effects of Ca(2+) and Pb(2+) were additive and blocked completely by the mitochondrial permeability transition pore (PTP) inhibitor cyclosporin A, whereas the calcineurin inhibitor FK506 had no effect. The caspase inhibitors carbobenzoxy-Leu-Glu-His-Asp-CH(2)F and carbobenzoxy-Asp-Glu-Val-Asp-CH(2)F, but not carbobenzoxy-Ile-Glu-Thr-Asp-CH(2)F, differentially blocked post-mitochondrial events. The levels of reduced and oxidized glutathione and pyridine nucleotides in rods were unchanged. Our results demonstrate that rod mitochondria are the target site for Ca(2+) and Pb(2+). Moreover, they suggest that Ca(2+) and Pb(2+) bind to the internal metal (Me(2+)) binding site of the PTP and subsequently open the PTP, which initiates the cytochrome c-caspase cascade of apoptosis in rods.
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PMID:Lead and calcium produce rod photoreceptor cell apoptosis by opening the mitochondrial permeability transition pore. 1076 53


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