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)

Apoptosis depends critically on regulated cytoskeletal reorganization events in a cell. We demonstrate that death effector domain containing DNA binding protein (DEDD), a highly conserved and ubiquitous death effector domain containing protein, exists predominantly as mono- or diubiquitinated, and that diubiquitinated DEDD interacts with both the K8/18 intermediate filament network and pro-caspase-3. Early in apoptosis, both cytosolic DEDD and its close homologue DEDD2 formed filaments that colocalized with and depended on K8/18 and active caspase-3. Subsequently, these filamentous structures collapsed into intracellular inclusions that migrated into cytoplasmic blebs and contained DEDD, DEDD2, active caspase-3, and caspase-3-cleaved K18 late in apoptosis. Biochemical studies further confirmed that DEDD coimmunoprecipitated with both K18 and pro-caspase-3, and kinetic analyses placed apoptotic DEDD staining prior to caspase-3 activation and K18 cleavage. In addition, both caspase-3 activation and K18 cleavage was inhibited by expression of DEDDDeltaNLS1-3, a cytosolic form of DEDD that cannot be ubiquitinated. Finally, siRNA mediated DEDD knockdown cells exhibited inhibition of staurosporine-induced DNA degradation. Our data suggest that DEDD represents a novel scaffold protein that directs the effector caspase-3 to certain substrates facilitating their ordered degradation during apoptosis.
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PMID:DEDD regulates degradation of intermediate filaments during apoptosis. 1223 23

DEDD, a highly conserved and ubiquitous death effector domain containing protein, exists in non, mono, and diubiquitinated forms. We previously reported that endogenous unmodified DEDD is only found in nucleoli and that mono- and diubiquitinated DEDD associate with caspase-3 in the cytosol suggesting that ubiquitination may be important to the apoptosis regulating functions of DEDD in the cytosol. We now demonstrate that many of its 16 lysine residues can serve as alternative acceptors for ubiquitination to maintain the monoubiquitination status of DEDD. A central region in DEDD (amino acids 109-305) outside the death effector domain was found to be essential for ubiquitination and/or the docking of the ubiquitination machinery. Fusion of ubiquitin to the C-terminus of DEDD to mimic monoubiquitinated DEDD relocated DEDD from nucleoli to the cytosol. This fusion protein also demonstrated a greater apoptosis potential than unmodified DEDD. Finally, we show that both mono- and polyubiquitination of DEDD can be achieved by the cellular inhibitor of apoptosis proteins 1 and 2 (cIAP-1/2). In addition, the cotransfection of DEDD with cIAP-1 or cIAP-2 results in the relocalization of the IAPs to the nucleoli. Our data suggest that monoubiquitination of DEDD regulates both its cytoplasmic localization and its proapoptotic potential and that IAP proteins can regulate DEDD's ubiquitination status.
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PMID:Fusing DEDD with ubiquitin changes its intracellular localization and apoptotic potential. 1623 27

The present study investigated the mechanism of mouse pancreatic acinar cell apoptosis induced by H(2)S in an in vitro system, using isolated pancreatic acini. Treatment of pancreatic acini with 10 microM NaHS (a donor of H(2)S) for 3 h caused phosphatidylserine externalization as shown by annexin V binding, an indicator of early stages of apoptosis. This treatment also resulted in the activation of the caspase cascade and major changes at the mitochondrial level. Caspase-3, -8, and -9 activities were stimulated by H(2)S treatment. Treatment with inhibitors of caspase-3, -8, and -9 significantly inhibited H(2)S-induced phosphatidylserine externalization as shown by reduced annexin V staining. The mitochondrial membrane potential was collapsed in H(2)S-treated acini as evidenced by fluorescence microscopy and quantitative analysis. Furthermore, the treatment of acini with H(2)S caused the release of cytochrome c by the mitochondria. To investigate the mechanism underlying pancreatic acinar cell apoptosis, we also characterized the protein expression of a range of molecules that are each known to influence the apoptotic pathway. Among proapoptotic proteins, Bax expression was activated in H(2)S-treated cells but not Bid, and the antiapoptotic proteins Bcl-X(L) and Bcl-2 did not show any activation in pancreatic acinar cell apoptosis. The death effector domain-containing protein Flip is downregulated in H(2)S-treated acini. These results demonstrate the induction of pancreatic acinar cell apoptosis in vitro by H(2)S and the involvement of both mitochondrial and death receptor pathways in the process of apoptosis.
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PMID:Mechanism of induction of pancreatic acinar cell apoptosis by hydrogen sulfide. 1659 18

The cytokeratin 8/18 (CK8/18) cytoskeleton network is an early target for caspase cleavage during apoptosis. Recent reports suggest that the highly conserved and ubiquitous death effector domain containing DNA binding protein (DEDD) plays a role in the recruitment of procaspase-9 and -3 at this CK8/18 scaffold. DEDD interacts with both the CK8/18 intermediate filament network and procaspase-3 and -9. It is suggested that the CK8/18 fibrils may provide a scaffold for the proximity-induced autocleavage and activation of procaspase-9 in close association with caspase-3.We addressed this issue by investigating DEDD staining patterns in various cell lines and by correlating these expression patterns with the sensitivity of these cell lines for roscovitine-induced apoptosis. We showed that in some cell lines DEDD revealed a bright filamentous staining pattern in others DEDD staining was weak and diffusely distributed in the cytoplasm of the cells. The difference in staining patterns was irrespective of the phosphorylation status of the cytokeratin filaments. In cells showing a filamentous staining pattern, DEDD was strongly associated with the CK8/18 cytokeratin filaments as evidenced by double immunofluorescence and its resistance to extraction with Triton X-100. Subcellular fractionation indicates that DEDD co-purifies with CK18, which corroborates a strong association of DEDD and the cytokeratin network. DEDD was either mono- or diubiquinated. Cells showing a filamentous DEDD distribution are more apoptosis-prone as evidenced by the rapid appearance of M30 CytoDeath-positive cells after induction of apoptosis. The sensitivity towards apoptosis is irrespective of the procaspase-3 content of the cells. Our data support the notion that DEDD-mediated accumulation of procaspases at the cytokeratin scaffold leads to an increase in the local concentration, which renders cells more apoptosis-prone.
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PMID:DEDD association with cytokeratin filaments correlates with sensitivity to apoptosis. 1682 Sep 59