Association of Active Caspase 8 with the Mitochondrial Membrane during Apoptosis: Potential Roles in Cleaving BAP31 and Caspase 3 and Mediating Mitochondrion-Endoplasmic Reticulum Cross Talk in Etoposide-Induced Cell Death
| Autor: | Dean G. Tang, Xiaodi Deng, Dhyan Chandra, Grace Choy, Peter T. Daniel, Bobby Bhatia |
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| Rok vydání: | 2004 |
| Předmět: |
Sucrose
Blotting Western Caspase 2 Down-Regulation Apoptosis Caspase 3 Endoplasmic Reticulum Transfection Caspase 8 Models Biological Cell Line Jurkat Cells Cell Line Tumor Centrifugation Density Gradient Humans RNA Small Interfering Cell Growth and Development Molecular Biology Caspase Etoposide Death domain Caspase-9 Cell Death Cell-Free System Dose-Response Relationship Drug biology NLRP1 Cell Membrane Membrane Proteins Cell Biology Antineoplastic Agents Phytogenic Molecular biology Mitochondria Protein Structure Tertiary Cell biology Enzyme Activation Microscopy Fluorescence Caspases biology.protein Caspase 10 Calcium Salts Endopeptidase K Protein Binding Subcellular Fractions |
| Zdroj: | Molecular and Cellular Biology. 24:6592-6607 |
| ISSN: | 1098-5549 |
| DOI: | 10.1128/mcb.24.15.6592-6607.2004 |
| Popis: | It was recently demonstrated that during apoptosis, active caspase 9 and caspase 3 rapidly accumulate in the mitochondrion-enriched membrane fraction (D. Chandra and D. G. Tang, J. Biol. Chem.278:17408-17420, 2003). We now show that active caspase 8 also becomes associated with the membranes in apoptosis caused by multiple stimuli. In MDA-MB231 breast cancer cells treated with etoposide (VP16), active caspase 8 is detected only in the membrane fraction, which contains both mitochondria and endoplasmic reticulum (ER), as revealed by fractionation studies. Immunofluorescence microscopy, however, shows that procaspase 8 and active caspase 8 predominantly colocalize with the mitochondria. Biochemical analysis demonstrates that both procaspase 8 and active caspase 8 are localized mainly on the outer mitochondrial membrane (OMM) as integral proteins. Functional analyses with dominant-negative mutants, small interfering RNAs, peptide inhibitors, and Fas-associated death domain (FADD)- and caspase 8-deficient Jurkat T cells establish that the mitochondrion-localized active caspase 8 results mainly from the FADD-dependent and tumor necrosis factor receptor-associated death domain-dependent mechanisms and that caspase 8 activation plays a causal role in VP16-induced caspase 3 activation and cell death. Finally, we present evidence that the OMM-localized active caspase 8 can activate cytosolic caspase 3 and ER-localized BAP31. Cleavage of BAP31 leads to the generation of ER- localized, proapoptotic BAP20, which may mediate mitochondrion-ER cross talk through a Ca(2+)-dependent mechanism. |
| Databáze: | OpenAIRE |
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