Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.2.30 (PARP)
 13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thiols such as cysteine and dithiothreitol are substrates for the ADP-ribosyltransferase activity of pertussis toxin. When cysteine was incubated with NAD+ and toxin at pH 7.5, a product containing ADP-ribose and cysteine (presumably ADP-ribosylcysteine) was isolated by high-performance liquid chromatography, and characterized by its composition and release of AMP with phosphodiesterase. Cysteine has a Km of 105 mM at saturating NAD+ concentration. The ability of thiols to act as a substrate is one explanation for the very high concentrations (250 mM or greater) that have been observed to enhance the apparent NAD glycohydrolase activity of the toxin.
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PMID:Thiol reagents are substrates for the ADP-ribosyltransferase activity of pertussis toxin. 313 46

Cysteine proteases of the interleukin 1 beta Converting Enzyme (ICE)/CED-3 family have been implicated in the effector process of apoptosis in several systems, including Fas-mediated apoptosis. We have recently isolated and partially characterized a protease present in extracts from anti-Fas antibody treated Jurkat T cells that promotes apoptotic changes in isolated nuclei (Schlegel, J., Peters, I., and Orrenius, S. (1995) FEBS Lett. 364, 139-142). We now show that this protease cleaves poly-(ADP-ribose) polymerase (PARP) with high efficiency and specificity. Both PARP proteolysis and the proapoptotic effects of the protease are inhibited by nanomolar concentrations of a selective inhibitor of apopain (CPP32), while an inhibitor of IL-1 beta converting enzyme is much less effective, requiring micromolar concentrations for the inhibition of the isolated protease. Kinetic analysis of the isolated protease reveals kinetic constants similar to those reported for apopain. The isolated protease is recognized by antibodies specific for CPP32/apopain but not by an anti-ICE antibody. Furthermore, a selective inhibitor of apopain prevents Fas-induced apoptosis in intact Jurkat T cells. We therefore conclude that CPP32/apopain is activated in Fas-induced apoptosis.
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PMID:CPP32/apopain is a key interleukin 1 beta converting enzyme-like protease involved in Fas-mediated apoptosis. 856 26

Cysteine proteases of the CED-3 and ICE family have been recently proposed as the ultimate executioners in several mammalian cell death pathways. Among them, the cysteine protease CPP32 has been shown to participate in programmed cell death (PCD), or apoptosis, affecting lymphoid cells in vitro. In the thymus, negative selection is a mechanism through which developing thymocytes expressing a TcR with high affinity for self peptide-MHC complexes are eliminated by PCD. In order to investigate the role of CPP32 in thymic apoptosis, isolated thymocytes were submitted to cell surface CD3 crosslinking by immobilized anti-CD3 mAb or to dexamethasone treatment. Although apoptosis occurred in the absence or after crosslinking with anti-CD3 mAb, specific activation of CPP32, as assessed by the extent of proteolytic cleavage of the p32 zymogen, was only detected in thymocytes cultured in the presence of the immobilized antibody or dexamethasone. This activation was a very early event during apoptosis as it occurred before the exposure of phosphatidyl serine to the upper side of the cell membrane. This was observed both in anti-CD3- and dexamethasone-induced apoptosis. Moreover, using mice transgenic for pigeon cytochrome C (PCC)-specific TcR, we were able to show that, after injection of PCC, the activation of CPP32 and cleavage of its substrate occurred in thymocytes obtained from mice expressing a permissive MHC haplotype for PCC presentation (H-2k). Moreover, PCC induced apoptosis was blocked by the caspase inhibitor zVAD. While spontaneous apoptosis was not accompanied by detectable levels of CPP32 processing, it was characterized by the proteolysis of poly(ADP-ribose) polymerase (PARP) and was blocked by the cysteine protease inhibitor, zVAD-CH2F. Taken together, these results support the concept that CPP32 is among the earliest effectors of the pathway leading to negative selection of autoreactive thymocytes. Our results also suggest the involvement of a distinct CPP32-like cysteine protease in spontaneous apoptosis of thymocytes.
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PMID:Specific activation of the cysteine protease CPP32 during the negative selection of T cells in the thymus. 934 8

The kidney is a target for toxicants including cisplatin and S-(1,2-dichlorovinyl)-L-cysteine (DCVC), a metabolite of the environmental contaminant, trichloroethylene. Necrosis is well characterized in kidney cells, but pathways leading to apoptosis are less clear. Cysteine conjugates are useful toxicants because they induce either necrosis or apoptosis depending on chemical structure or antioxidant status. Herein, we show that in the renal epithelial cell line LLC-PK1, activation of caspase-3 (CPP32/Yama/apopain) is crucial for apoptosis, but not necrosis. Apoptosis was blocked by zVAD.fmk, and partially by a cathepsin inhibitor. Caspase-3 activity and cleavage of poly(ADP-ribose) polymerase (PARP) was detected only during apoptosis. S-(1,1,2,2-Tetrafluoroethyl)-L-cysteine (TFEC), a metabolite of tetrafluoroethylene, kills cells only by necrosis, and did not activate caspases under any conditions. Apoptosis and activation of caspase-3 by cisplatin, but not DCVC, was prevented by bcl-2. Thus, caspase-3 activation by bcl-2-dependent and -independent mechanisms is a terminal event in chemical-apoptosis of renal epithelial cells.
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PMID:The roles of caspase-3 and bcl-2 in chemically-induced apoptosis but not necrosis of renal epithelial cells. 1059 53

Earlier studies from our laboratory have demonstrated that Oxyresveratrol (OXY), a hydroxyl-substituted stilbene, exhibits potent inhibition of human melanoma cell proliferation. The present study defines a cytotoxic effect of OXY on the highly chemo-resistant, triple-negative human breast cancer cell line MDA-MB-231. OXY-mediated cell death resulted in accumulation of cells at the sub-G1 phase of the cell cycle, induced chromatin condensation, DNA fragmentation, phosphatidylserine externalization and PARP cleavage, indicative of apoptosis. Interestingly, morphology and cell viability studies with the pan-caspase inhibitor, QVD-OPH revealed that OXY-induced cell death was caspase-independent. Docking studies also showed that OXY can bind to the S1 site of caspase-3, and could also exert an inhibitory effect on this executioner caspase. The immunoblot analysis demonstrating the absence of caspase cleavage during cell death further confirmed these findings. OXY was also observed to induce the production of reactive oxygen species, which caused the depolarization of the mitochondrial membrane resulting in translocation of Apoptosis Inducing Factor (AIF) into the nucleus. Pretreatment of the cells with N-Acetyl Cysteine antioxidant prevented cell death resulting from OXY treatment. Thus, OXY initiates ROS-mediated, apoptosis-like cell death, involving mitochondrial membrane depolarization, translocation of AIF into the nucleus, and DNA fragmentation, resulting in caspase-independent cell death in MDA-MB-231 cells. The cytotoxicity manifested by OXY was also observed in 3D cell culture models and primary cells, thereby providing a basis for the utilization of OXY as a novel template for the future design of anticancer therapeutics.
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PMID:Oxyresveratrol drives caspase-independent apoptosis-like cell death in MDA-MB-231 breast cancer cells through the induction of ROS. 3175 27