biostudies-literatureUnknown20(15)Stegh AHCaspase 8 plays an essential role in the execution of death receptor-mediated apoptosis. To determine the localization of endogenous caspase 8, we used a panel of subunit-specific anti-caspase 8 monoclonal antibodies in confocal immunofluorescence microscopy. In the human breast carcinoma cell line MCF7, caspase 8 predominantly colocalized with and bound to mitochondria. After induction of apoptosis through CD95 or tumor necrosis factor receptor I, active caspase 8 translocated to plectin, a major cross-linking protein of the three main cytoplasmic filament systems, whereas the caspase 8 prodomain remained bound to mitochondria. Plectin was quantitatively cleaved by caspase 8 at Asp 2395 in the center of the molecule in all cells tested. Cleavage of plectin clearly preceded that of other cMolecular and cellular biology5665-79https://www.ebi.ac.uk/biostudies/studies/S-EPMC86037biostudies-literatureIdentification of the cytolinker plectin as a major early in vivo substrate for caspase 8 during CD95- and tumor necrosis factor receptor-mediated apoptosis.PMC86037Seper MAndra KPeter MEHerrmann HStegh AHWiche GKrammer PHLampel SWeisenberger DfalseIdentification of the cytolinker plectin as a major early in vivo substrate for caspase 8 during CD95- and tumor necrosis factor receptor-mediated apoptosis.Caspase 8 plays an essential role in the execution of death receptor-mediated apoptosis. To determine the localization of endogenous caspase 8, we used a panel of subunit-specific anti-caspase 8 monoclonal antibodies in confocal immunofluorescence microscopy. In the human breast carcinoma cell line MCF7, caspase 8 predominantly colocalized with and bound to mitochondria. After induction of apoptosis through CD95 or tumor necrosis factor receptor I, active caspase 8 translocated to plectin, a major cross-linking protein of the three main cytoplasmic filament systems, whereas the caspase 8 prodomain remained bound to mitochondria. Plectin was quantitatively cleaved by caspase 8 at Asp 2395 in the center of the molecule in all cells tested. Cleavage of plectin clearly preceded that of other c2000-01-01T00:00:00Z2000 Aug2025-04-05T10:13:52.011Z2019-03-27T00:18:20ZS-EPMC860371089150310.1128/MCB.20.15.5665-5679.2000