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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two novel synthetic tetrapeptides, VEID-CHO and DMQD-CHO, could selectively inhibit caspase-6 and caspase-3, respectively. We used these inhibitors to dissect the pathway of caspase activation in Fas-stimulated Jurkat cells and identify the roles of each active caspase in apoptotic processes. Affinity labeling techniques revealed a branched protease cascade in which caspase-8 activates caspase-3 and -7, and caspase-3, in turn, activates caspase-6. Both caspase-6 and -3 have major roles in nuclear apoptosis. Caspase-6 cleaves nuclear mitotic apparatus protein (NuMA) and mediates the shrinkage and fragmentation of nuclei. Caspase-3 cleaves NuMA at sites distinct from caspase-6, and mediates DNA fragmentation and chromatin condensation. It is also involved in extranuclear apoptotic events: cleavage of PAK2, formation of apoptotic bodies, and exposure of phosphatidylserine on the cell surface. In contrast, a caspase(s) distinct from caspase-3 or -6 mediates the disruption of mitochondrial membrane potential (permeability transition) and the shrinkage of cytoplasm. These findings demonstrate that caspases are organized in a protease cascade, and that each activated caspase plays a distinct role(s) in the execution of Fas-induced cell death.
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PMID:Caspases are activated in a branched protease cascade and control distinct downstream processes in Fas-induced apoptosis. 946 9

Although the commonly activated death protease caspase-3 appears not to be essential for apoptosis during development except in the brain, it was not shown whether substrates known to be cleaved by caspase-3 are still proteolyzed in its absence. We have addressed this question with MCF-7 breast carcinoma cells that we recently showed lack caspase-3 owing to the functional deletion of the CASP-3 gene. Tumor necrosis factor- or staurosporine-induced apoptosis of caspase-3-deficient MCF-7 cells resulted in cleavage of the death substrates PARP, Rb, PAK2, DNA-PKcs, gelsolin, and DFF-45, but not alpha-fodrin. In contrast, all these substrates including alpha-fodrin were cleaved in apoptotic HeLa cells expressing caspase-3. Introduction of CASP-3 cDNA, but not CASP-10 cDNA, into MCF-7 cells restored alpha-fodrin cleavage. In addition, tumor necrosis factor- or staurosporine-induced apoptosis of MCF-7 cells stably expressing pro-caspase-3 also resulted in alpha-fodrin cleavage. Although the specific caspase inhibitory peptides Z-VAD-fmk and Z-DEVD-fmk prevented apoptosis of MCF-7 cells, we were unable to detect activation of caspases 2 and 7, which are known to be inhibited by Z-DEVD-fmk. Together our results suggest that caspase-3 is essential for cleavage of alpha-fodrin, but dispensable for the cleavage of PARP, Rb, PAK2, DNA-PKcs, gelsolin, and DFF-45 and imply that one or more caspases other than caspases 2, 3, and 7 is activated and plays a crucial role in the cleavage of these substrates in MCF-7 cells.
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PMID:Caspase-3 is required for alpha-fodrin cleavage but dispensable for cleavage of other death substrates in apoptosis. 962 43

Exposure of mammalian cells to ultraviolet (UV) light elicits a cellular response and can also lead to apoptotic cell death. In this report, we show that a 36-kDa myelin basic protein (MBP) kinase detected by an in-gel kinase assay can be dramatically activated during the early stages of UV irradiation-triggered apoptosis of A431 cells. Immunoblot analysis revealed that this 36-kDa MBP kinase could be recognized by an antibody against the C-terminal regions of a family of p21Cdc42/Rac-activated kinases (PAKs). By using this antibody and a PAK2-specific antibody against the N-terminal region of PAK2 as studying tools, we further demonstrated that UV irradiation caused cleavage of PAK2 to generate a 36-kDa C-terminal catalytic fragment and a 30-kDa N-terminal fragment in A431 cells. The appearance of the 36-kDa C-terminal catalytic fragment of PAK2 matched exactly with the activation of the 36-kDa MBP kinase in A431 cells upon UV irradiation. In addition, UV irradiation also led to activation of CPP32/caspase-3, but not ICH-1L/caspase-2 and ICE/caspase-1, in A431 cells and the kinetics of activation of CPP32/caspase-3 appeared to correlate well with that of DNA fragmentation and of cleavage/activation of PAK2, respectively. Moreover, blockage of activation of CPP32/caspase-3 by pretreating the cells with two specific tetrapeptidic inhibitors for caspases (Ac-DEVD-cho and Ac-YVAD-cmk) could significantly attenuate the extent of cleavage/activation of PAK2 induced by UV irradiation. Collectively, the results demonstrate that cleavage and activation of PAK2 can be induced during the early stages of UV irradiation-triggered apoptosis and indicate the involvement of CPP32/caspase-3 in this process.
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PMID:Proteolytic cleavage and activation of PAK2 during UV irradiation-induced apoptosis in A431 cells. 971 43

Heat shock induces a stress response in mammalian cells and can also lead to apoptotic cell death. Here we report that a 36-kDa myelin basic protein (MBP) kinase detected by an in-gel kinase assay can be drastically activated in several cell types by heat shock. Immunoblot analysis revealed that this 36-kDa MBP kinase can be recognized by an antibody against the C-terminal region of a family of p21Cdc42/Rac-activated kinases (PAKs). By using this antibody and a PAK2-specific antibody against the N-terminal region of PAK2 as tools, we further demonstrated that heat shock can induce cleavage of PAK2 to generate a 36-kDa C-terminal catalytic fragment in mouse Balb/c 3T3 and human Hep 3B cells. The kinetic profile of appearance of the 36-kDa C-terminal catalytic fragment of PAK2 matched exactly with the activation of the 36-kDa MBP kinase in these cells induced by heat shock. In addition, the heat shock-induced cleavage and activation of PAK2 was found to be closely associated with both DNA fragmentation and activation of an ICE/CED-3 family cysteine protease termed caspase-3 in heat shock-treated Hep 3B cells. Moreover, blockage of the activation of caspase-3 by pretreating the cells with two specific tetrapeptidic inhibitors of caspases (Ac-DEVD-cho and Ac-YVAD-cmk) could substantially diminish the extent of heat shock-induced cleavage/activation of PAK2. Overall, our results point out that PAK2 is cleaved and activated during the heat shock-induced apoptotic cell death process and suggest that caspase-3 is involved in this process.
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PMID:Heat shock stress induces cleavage and activation of PAK2 in apoptotic cells. 971 44

Hyperosmotic shock elicits a stress response in mammalian cells and can lead to apoptotic cell death. In the present study, we report that hyperosmotic shock can induce activation of a 36 kDa kinase detected by an in-gel kinase assay in several cell types, including mouse Balb/c 3T3 fibroblasts, and human Hep 3B and A431 cells. This 36 kDa kinase can be recognized by an antibody against the C-terminal region of a family of p21Cdc42/Rac-activated kinases (PAKs) on immunoblot. Further studies with this antibody and a PAK2-specific antibody against the N-terminal region of PAK2 demonstrate that hyperosmotic shock can induce cleavage of PAK2 to generate a 36 kDa C-terminal catalytic fragment in cells. The cleavage and activation of PAK2 was found to be closely associated with both DNA fragmentation and activation of an ICE/CED-3 family cysteine protease termed caspase-3 in hyperosmotically shocked cells. Furthermore, pretreating the cells with two caspase inhibitors (Ac-DEVD-cho and Ac-YVAD-cmk) could inhibit both cleavage/activation of PAK2 and DNA fragmentation induced by hyperosmotic shock. Moreover, all these hyperosmotic shock-induced changes (i.e., activation of caspase-3, cleavage/activation of PAK2, and DNA fragmentation) in cells could be blocked by antioxidants such as ascorbic acid (vitamine C), alpha-tocopherol (vitamine E), dithiothreitol, beta-mercaptoethanol, and glutathione. Taken together, our results show that PAK2 is cleaved and activated via a caspase-dependent mechanism during hyperosmotic shock-induced apoptosis and suggest the involvement of antioxidant-preventable oxidative stress in inducing this process.
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PMID:PAK2 is cleaved and activated during hyperosmotic shock-induced apoptosis via a caspase-dependent mechanism: evidence for the involvement of oxidative stress. 998 86

Traumatic spinal cord injury often results in complete loss of voluntary motor and sensory function below the site of injury. The long-term neurological deficits after spinal cord trauma may be due in part to widespread apoptosis of neurons and oligodendroglia in regions distant from and relatively unaffected by the initial injury. The caspase family of cysteine proteases regulates the execution of the mammalian apoptotic cell death program. Caspase-3 cleaves several essential downstream substrates involved in the expression of the apoptotic phenotype in vitro, including gelsolin, PAK2, fodrin, nuclear lamins and the inhibitory subunit of DNA fragmentation factor. Caspase-3 activation in vitro can be triggered by upstream events, leading to the release of cytochrome c from the mitochondria and the subsequent transactivation of procaspase-9 by Apaf-1. We report here that these upstream and downstream components of the caspase-3 apoptotic pathway are activated after traumatic spinal cord injury in rats, and occur early in neurons in the injury site and hours to days later in oligodendroglia adjacent to and distant from the injury site. Given these findings, targeting the upstream events of the caspase-3 cascade has therapeutic potential in the treatment of acute traumatic injury to the spinal cord.
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PMID:Activation of the caspase-3 apoptotic cascade in traumatic spinal cord injury. 1042 20

Photodynamic treatment (PDT) elicits diverse cellular responses and can also cause apoptosis. In the present study the cascade of signalling events involved in PDT-induced apoptosis was investigated using Rose Bengal (RB) as the photosensitizer, and human epidermal carcinoma A431 cells as the cell model. We show that a 36-kDa kinase detected by an in-gel kinase assay is markedly activated during PDT-triggered apoptosis. Immunoblot analysis revealed that this 36-kDa kinase represents the C-terminal catalytic fragment of p21-activated kinase (PAK)2. Generation of this active fragment of PAK2 is mediated by the caspase family of proteases, which are activated by PDT. The specific caspase inhibitors (acetyl-Asp-Glu-Val-Asp-aldehyde and acetyl-Tyr-Val-Ala-Asp-chloromethylketone) block the PDT-induced caspase-3 activation and subsequent PAK2 cleavage/activation, indicating a major role for the caspase family proteases in PDT-induced apoptosis. Both PDT-induced caspase-3 activation and PAK2 cleavage/activation can be inhibited by the singlet oxygen scavengers, L-histidine and alpha-tocopherol, but not the hydroxyl radical scavenger, mannitol, demonstrating that singlet oxygen is an immediate early-apoptotic signal generated by PDT. In addition, PDT can induce a two-stage activation of the c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) in A431 cells; the early-stage JNK activation is singlet oxygen-dependent, whereas the late-stage JNK activation is mediated by the singlet oxygen-triggered caspase activation. Experiments using anti-sense oligonucleotides against JNK1 and PAK2 further show that during PDT-induced apoptosis the early-stage JNK activation is required for caspase activation, and that the late-stage JNK activation is regulated by the caspase-mediated cleavage/activation of PAK2. Collectively, a model for the PDT-triggered apoptotic signalling cascade with RB is proposed, which involves singlet oxygen, JNK, caspase-3 and PAK2, sequentially.
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PMID:Apoptotic signalling cascade in photosensitized human epidermal carcinoma A431 cells: involvement of singlet oxygen, c-Jun N-terminal kinase, caspase-3 and p21-activated kinase 2. 1099 65

Apoptosis (programmed cell death) is an active physiological mechanism from which removal of abundant or potentially harmful cells follows. Apoptosis of lymphocytes is critical for the development of the immune system and during the immune response. As we have shown previously, moderate osmotic cell shrinkage interferes with CD95(Fas/Apo-1)-induced cell death. The present study has been performed to further elucidate the underlying mechanisms. To this end, apoptosis in Jurkat T-lymphocytes was elicited by triggering the CD95-receptor with monoclonal CD95/Fas-antibody. Osmotic cell shrinkage which was induced by the addition of 100 mM NaCl, did not significantly interfere with CD95-induced phosphatidylserine exposure nor the activation of caspase 3 activity as determined by PARP cleavage, DEVD-AMC consumption, or the activation of PAK2-kinase. However, osmotic cell shrinkage almost abolished CD95-induced DNA fragmentation (as revealed by propidium iodide staining) and the activation of a DNase as evidenced from SDS-PAGE gel assay. Western blot analysis showed CD95-induced tyrosine phosphorylation of a nuclear protein of ca. 20 kD which comigrated with nuclease activity. This tyrosine phosphorylation was almost completely abolished by the addition of 100 mM NaCl. Furthermore, osmotic cell shrinkage blunted the CD95-induced activation of the Src-like kinase p56lck. It is concluded that different signaling pathways mediate FITC-Annexin-V binding and DNase activation. Only the latter is sensitive to osmotic cell shrinkage.
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PMID:Inhibition of CD95/Fas-induced DNA degradation by osmotic cell shrinkage. 1109 32

The p21-activated protein kinase gamma-PAK, also known as PAK2, has very different properties from the other two highly conserved isoforms of the PAK family, alpha-PAK (PAK1) and beta-PAK (PAK3). gamma-PAK has cytostatic activity, as shown by inhibition of cleavage of early frog embryos following microinjection of gamma-PAK and by inhibition of growth when expressed in mammalian cells. gamma-PAK is activated in response to a variety of stresses including radiation- and chemically-induced DNA damage, hyperosmolarity, addition of sphingosine, serum starvation, and contact inhibition. Activation occurs through at least two signaling pathways, depending on the type of stress, one of which requires phosphoinositide 3-kinase and/or tyrosine kinase activity. During apoptosis gamma-PAK is cleaved by caspase 3 and activated and appears to have a role in the apoptotic response. gamma-PAK is present in the cytosol, associated with the membrane and in secretory granules. A wide variety of substrates have been identified for gamma-PAK. We propose gamma-PAK may be involved in coordinating the stress response, possibly in conjunction with other stress response proteins.
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PMID:Cytostatic p21 G protein-activated protein kinase gamma-PAK. 1134 98

Ultraviolet (UV) light is a strong apoptotic trigger that induces caspase-dependent biochemical changes in cells. Previously we showed that UV irradiation can activate caspase-3, and the subsequent cleavage and activation of p21(Cdc42/Rac)-activated kinase 2 (PAK2) in human epidermoid carcinoma A431 cells. In this study we demonstrate that curcumin (Cur), the yellow pigment of Curcuma longa with known anti-oxidant and anti-inflammatory properties, can prevent UV irradiation-induced apoptotic changes, including c-Jun N-terminal kinase (JNK) activation, loss of mitochondrial membrane potential (MMP), mitochondrial release of cytochrome C, caspase-3 activation, and cleavage/activation of PAK2 in A431 cells. Flow cytometric analysis using the cell permeable dye 2',7'-dichlorofluorescin diacetate (DCF-DA) as an indicator of reactive oxygen species (ROS) generation revealed that the increase in intracellular oxidative stress caused by UV irradiation could be abolished by Cur. In addition, we found that SP600125, a JNK-specific inhibitor, reduced UV irradiation-induced JNK activation as well as caspase-3 activation, indicating that JNK activity is required for UV irradiation-induced caspase activation. Collectively, our results demonstrate that Cur significantly attenuates UV irradiation-induced ROS formation, and suggest that ROS triggers JNK activation, which in turn causes MMP change, cytochrome C release, caspase activation, and subsequent apoptotic biochemical changes.
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PMID:Curcumin inhibits UV irradiation-induced oxidative stress and apoptotic biochemical changes in human epidermoid carcinoma A431 cells. 1450 49


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