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c-FLIP(S) reduces activation of caspase and NF-kappaB pathways and decreases T cell survival

Jennifer Hinshaw-Makepeace1, Gail Huston, Karen A Fortner

  • 1Immunobiology Program, Department of Medicine, The University of Vermont College of Medicine, Burlington, VT 05405-0068, USA.

European Journal of Immunology
|December 18, 2007
PubMed

Insights

Cellular FLIP short-form (c-FLIP(S)) inhibits caspase-8 activation in T cells, reducing NF-kappaB activity and promoting T cell death. This suggests c-FLIP(S) limits T cell expansion during immune responses.

Area of Science:

  • Immunology
  • Molecular Biology
  • Cell Signaling

Background:

  • T cell activation relies on Nuclear Factor-kappaB (NF-kappaB) signaling, which is initiated by caspase-8 activity.
  • Cellular FLIP (c-FLIP) is a caspase-8 homolog that regulates its activity, with two main forms: c-FLIP long (c-FLIP(L)) and c-FLIP short (c-FLIP(S)).

Purpose of the Study:

  • To investigate the role of c-FLIP(S) in regulating caspase-8 activity during T cell activation.
  • To determine the impact of c-FLIP(S) on NF-kappaB pathway signaling and T cell survival.

Main Methods:

  • Utilized T cells from c-FLIP(S)-transgenic mice.
  • Assessed caspase-8 activation, MALT1 and Bcl-10 recruitment, and NF-kappaB activity.
  • Analyzed T cell death rates spontaneously and upon activation.

Main Results:

  • c-FLIP(S) inhibits caspase-8 activation in T cells, unlike c-FLIP(L).
  • This inhibition leads to reduced MALT1 and Bcl-10 recruitment and decreased NF-kappaB activity.
  • T cells from c-FLIP(S)-transgenic mice exhibit increased cell death.

Conclusions:

  • c-FLIP(S) acts as a negative regulator of T cell activation by inhibiting caspase-8.
  • The findings indicate that c-FLIP(S) plays a crucial role in limiting T cell expansion during immune responses.

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