Identification of the cytolinker plectin as a major early in vivo substrate for caspase 8 during CD95- and tumor necrosis factor receptor-mediated apoptosis

Mol Cell Biol. 2000 Aug;20(15):5665-79. doi: 10.1128/MCB.20.15.5665-5679.2000.

Abstract

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 caspase substrates such as poly(ADP-ribose) polymerase, gelsolin, cytokeratins, or lamin B. In primary fibroblasts from plectin-deficient mice, apoptosis-induced reorganization of the actin cytoskeleton, as seen in wild-type cells, was severely impaired, suggesting that during apoptosis, plectin is required for the reorganization of the microfilament system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Actins / ultrastructure
  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / pharmacology
  • Apoptosis / drug effects
  • Apoptosis / physiology*
  • Biological Transport
  • Breast Neoplasms
  • Carcinoma
  • Caspase 8
  • Caspase 9
  • Caspases / immunology
  • Caspases / metabolism*
  • Cytoplasm / metabolism
  • Enzyme Precursors / metabolism
  • Fibroblasts / metabolism
  • Gelsolin / metabolism
  • Humans
  • Intermediate Filament Proteins / genetics
  • Intermediate Filament Proteins / metabolism*
  • Keratins / metabolism
  • Lamin Type B
  • Lamins
  • Mice
  • Mice, Mutant Strains
  • Mitochondria / metabolism
  • Molecular Sequence Data
  • Nuclear Proteins / metabolism
  • Plectin
  • Receptors, Tumor Necrosis Factor / metabolism*
  • Substrate Specificity
  • Tumor Cells, Cultured
  • fas Receptor / metabolism*

Substances

  • Actins
  • Antibodies, Monoclonal
  • Enzyme Precursors
  • Gelsolin
  • Intermediate Filament Proteins
  • Lamin Type B
  • Lamins
  • Nuclear Proteins
  • PLEC protein, human
  • Plec protein, mouse
  • Plectin
  • Receptors, Tumor Necrosis Factor
  • fas Receptor
  • Keratins
  • CASP8 protein, human
  • CASP9 protein, human
  • Casp8 protein, mouse
  • Casp9 protein, mouse
  • Caspase 8
  • Caspase 9
  • Caspases