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A novel protein domain required for apoptosis. Mutational analysis of human Fas antigen

N Itoh1, S Nagata

  • 1Osaka Bioscience Institute, Japan.

The Journal of Biological Chemistry
|May 25, 1993
PubMed

Insights

The Fas antigen mediates apoptosis. Specific cytoplasmic domains regulate its cell-killing activity, with a conserved 68-amino acid region crucial for apoptotic signaling.

Area of Science:

  • Immunology
  • Molecular Biology
  • Cell Biology

Background:

  • Fas antigen is a cell surface protein mediating apoptosis.
  • It belongs to the tumor necrosis factor receptor superfamily.
  • Fas-mediated apoptosis plays a role in immune regulation and homeostasis.

Purpose of the Study:

  • To investigate the role of the cytoplasmic region of the Fas antigen in apoptosis.
  • To identify specific domains within the Fas antigen cytoplasmic tail responsible for signal transduction and regulation.
  • To characterize the functional significance of conserved regions in Fas-mediated cell death.

Main Methods:

  • Expression of human Fas antigen and its mutants in murine L929 and T-cell lymphoma WR19L cells.
  • Treatment with anti-human Fas antibody to induce apoptosis.
  • Analysis of cell viability and killing activity in a concentration-dependent manner.
  • Site-directed mutagenesis to create deletions in the Fas antigen cytoplasmic region.

Main Results:

  • Anti-Fas antibody induced cell death in L929 and WR19L cells expressing human Fas antigen.
  • A 15-amino acid deletion at the C-terminus enhanced Fas antibody-induced killing.
  • Further deletion of this region abolished the killing activity.
  • A conserved 68-amino acid domain within the cytoplasmic region was identified as critical for apoptotic signal transduction.

Conclusions:

  • The cytoplasmic region of Fas antigen contains both inhibitory and signal-transducing domains.
  • A novel 68-amino acid domain is essential for mediating Fas-induced apoptosis.
  • This conserved domain is critical for apoptotic signal transduction in the Fas pathway.

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