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Determination of Lipid Raft Partitioning of Fluorescently-tagged Probes in Living Cells by Fluorescence Correlation Spectroscopy (FCS)
10:59

Determination of Lipid Raft Partitioning of Fluorescently-tagged Probes in Living Cells by Fluorescence Correlation Spectroscopy (FCS)

Published on: April 6, 2012

Modulation of Fas-mediated apoptosis by lipid rafts in T lymphocytes

Patrick Legembre1, Sophie Daburon, Patrick Moreau

  • 1Laboratoire Composantes Innées de la Réponse Immunitaire et Différenciation, Centre National de la Recherche Scientifique Unité Mixte de Recherche 5164, University of Bordeaux, France. patrick.legembre@u-bordeaux2.fr

Journal of Immunology (Baltimore, Md. : 1950)
|January 6, 2006
PubMed

Insights

Different cell membrane microdomains regulate Fas-mediated apoptosis in human T cells. CD28 recruitment amplifies Fas signaling, while CD55 or CD59 inhibit it, controlling cell death at the membrane level.

Area of Science:

  • Cell Biology
  • Immunology
  • Molecular Biology

Background:

  • Fas-mediated apoptosis differs between cell types, requiring lipid rafts in type I cells but not type II.
  • Understanding the role of specific membrane proteins within these rafts is crucial for deciphering apoptosis regulation.

Purpose of the Study:

  • To investigate the distinct roles of CD28, CD59, and CD55 localization within lipid rafts in modulating Fas signaling in human T cells.
  • To determine if different microdomains differentially affect Fas-induced apoptosis.

Main Methods:

  • Immunofluorescence microscopy to visualize protein localization within lipid rafts.
  • Co-immunoprecipitation assays to study protein interactions.
  • Flow cytometry to assess Fas-mediated apoptosis upon protein coligation or cross-linking.

Main Results:

  • CD28, CD59, and CD55 localize to lipid rafts in human T cells.
  • CD28 concentrates in GM1-enriched microdomains, distinct from CD59 and CD55.
  • CD28 cross-linking forms raft clusters excluding CD59/CD55, and vice versa.
  • Coligation of Fas with CD55/CD59 inhibits apoptosis, while CD28 recruitment amplifies Fas signaling.

Conclusions:

  • Distinct microdomains with unique functional properties exist on the cell surface.
  • The recruitment of specific microdomains differentially modulates the Fas pathway.
  • Fas-induced apoptosis can be precisely controlled at the cytoplasmic membrane level through protein interactions within microdomains.

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