Caspase-3 is a component of Fas death-inducing signaling complex in lipid rafts and its activity is required for complete caspase-8 activation during Fas-mediated cell death

J Immunol. 2004 Feb 15;172(4):2316-23. doi: 10.4049/jimmunol.172.4.2316.

Abstract

Since its discovery, caspase-8 has been placed at the apex of the proteolytic cascade triggered by death receptor (DR) cross-linking. Because of its capacity to interact with the cytoplasmic portion of DR, it has been suggested that caspase-8 acts independently of other caspases in the initiation of Fas and other DR signaling. In this study, we demonstrate that in Jurkat cells, caspase-3 cleavage is an early step during Fas-induced apoptosis. We show that caspase-3 processing into its p20 occurs rapidly after Fas cross-linking, in the absence of mitochondrial depolarization and caspase-9 activation. Moreover, caspase-3 is present in lipid rafts of untreated Jurkat cells and peripheral T lymphocytes. Caspase-3, caspase-8, and Fas-associated death domain are further recruited to lipid rafts of Jurkat cells following anti-Fas treatment. Fas immunoprecipitation reveals that caspase-3 is a component of the death-inducing signaling complex, suggesting that this cysteine protease is in close proximity to caspase-8. Furthermore, transduction of Jurkat cells with a caspase-3 dominant-negative form inhibits caspase-8 processing and results in inhibition of apoptosis, suggesting that caspase-3 activity is required for caspase-8 activation. Overall, these findings support a model whereby caspase-3 is a component of the death-inducing signaling complex located in lipid rafts, and as such, is involved in the amplification of caspase-8 activity by the mitochondrion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / immunology*
  • Caspase 3
  • Caspase 8
  • Caspases / biosynthesis
  • Caspases / metabolism*
  • Caspases / physiology
  • Death Domain Receptor Signaling Adaptor Proteins
  • Enzyme Activation / immunology
  • Fas Ligand Protein
  • Humans
  • Hydrolysis
  • Intracellular Membranes / enzymology
  • Intracellular Membranes / immunology
  • Jurkat Cells
  • Ligands
  • Membrane Glycoproteins / metabolism
  • Membrane Glycoproteins / physiology
  • Membrane Microdomains / enzymology
  • Membrane Microdomains / physiology*
  • Membrane Potentials / immunology
  • Mitochondria / enzymology
  • Mitochondria / immunology
  • Protein Processing, Post-Translational / immunology
  • Receptors, Tumor Necrosis Factor / metabolism
  • Receptors, Tumor Necrosis Factor / physiology*
  • Signal Transduction / immunology*
  • T-Lymphocytes / cytology
  • T-Lymphocytes / enzymology
  • T-Lymphocytes / immunology
  • fas Receptor / immunology
  • fas Receptor / metabolism
  • fas Receptor / physiology*

Substances

  • Death Domain Receptor Signaling Adaptor Proteins
  • FASLG protein, human
  • Fas Ligand Protein
  • Ligands
  • Membrane Glycoproteins
  • Receptors, Tumor Necrosis Factor
  • fas Receptor
  • CASP3 protein, human
  • CASP8 protein, human
  • Caspase 3
  • Caspase 8
  • Caspases