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Polyunsaturated Fatty Acids Inhibit T Cell Signal Transduction by Modification of Detergent-insoluble Membrane Domains

Polyunsaturated Fatty Acids Inhibit T Cell Signal Transduction by Modification of... Polyunsaturated fatty acids (PUFAs) exert immunosuppressive effects, but the molecular alterations leading to T cell inhibition are not yet elucidated. Signal transduction seems to involve detergent-resistant membrane domains (DRMs) acting as functional rafts within the plasma membrane bilayer with Src family protein tyrosine kinases being attached to their cytoplasmic leaflet. Since DRMs include predominantly saturated fatty acyl moieties, we investigated whether PUFAs could affect T cell signaling by remodeling of DRMs. Jurkat T cells cultured in PUFA-supplemented medium showed a markedly diminished calcium response when stimulated via the transmembrane CD3 complex or glycosyl phosphatidylinositol (GPI)- anchored CD59. Immunofluorescence studies indicated that CD59 but not Src family protein tyrosine kinase Lck remained in a punctate pattern after PUFA enrichment. Analysis of DRMs revealed a marked displacement of Src family kinases (Lck, Fyn) from DRMs derived from PUFA-enriched T cells compared with controls, and the presence of Lck in DRMs strictly correlated with calcium signaling. In contrast, GPI-anchored proteins (CD59, CD48) and ganglioside GM1, both residing in the outer membrane leaflet, remained in the DRM fraction. In conclusion, PUFA enrichment selectively modifies the cytoplasmic layer of DRMs and this alteration could underlie the inhibition of T cell signal transduction by PUFAs. fatty acids membrane lipids lymphocytes signal transduction protein-tyrosine kinases Footnotes Address all correspondence to T.M. Stulnig, Dept. of Internal Medicine III, Division of Endocrinology and Metabolism, University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. Tel.: 43 1 40400 4319. Fax: 43 1 40400 4845. E-mail: thomas.stulnig@akh-wien.ac.at Abbreviations used in this paper: BHT butylated hydroxy-toluene EtOH ethanol DRM detergent-resistant membrane domain GAM goat anti–mouse antibody GPI glycosyl phosphatidylinositol PUFA polyunsaturated fatty acid TCR T cell receptor Submitted: 13 May 1998 Revision received 2 September 1998 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Cell Biology Rockefeller University Press

Polyunsaturated Fatty Acids Inhibit T Cell Signal Transduction by Modification of Detergent-insoluble Membrane Domains

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References (60)

Publisher
Rockefeller University Press
Copyright
© 1998 Rockefeller University Press
ISSN
0021-9525
eISSN
1540-8140
DOI
10.1083/jcb.143.3.637
Publisher site
See Article on Publisher Site

Abstract

Polyunsaturated fatty acids (PUFAs) exert immunosuppressive effects, but the molecular alterations leading to T cell inhibition are not yet elucidated. Signal transduction seems to involve detergent-resistant membrane domains (DRMs) acting as functional rafts within the plasma membrane bilayer with Src family protein tyrosine kinases being attached to their cytoplasmic leaflet. Since DRMs include predominantly saturated fatty acyl moieties, we investigated whether PUFAs could affect T cell signaling by remodeling of DRMs. Jurkat T cells cultured in PUFA-supplemented medium showed a markedly diminished calcium response when stimulated via the transmembrane CD3 complex or glycosyl phosphatidylinositol (GPI)- anchored CD59. Immunofluorescence studies indicated that CD59 but not Src family protein tyrosine kinase Lck remained in a punctate pattern after PUFA enrichment. Analysis of DRMs revealed a marked displacement of Src family kinases (Lck, Fyn) from DRMs derived from PUFA-enriched T cells compared with controls, and the presence of Lck in DRMs strictly correlated with calcium signaling. In contrast, GPI-anchored proteins (CD59, CD48) and ganglioside GM1, both residing in the outer membrane leaflet, remained in the DRM fraction. In conclusion, PUFA enrichment selectively modifies the cytoplasmic layer of DRMs and this alteration could underlie the inhibition of T cell signal transduction by PUFAs. fatty acids membrane lipids lymphocytes signal transduction protein-tyrosine kinases Footnotes Address all correspondence to T.M. Stulnig, Dept. of Internal Medicine III, Division of Endocrinology and Metabolism, University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. Tel.: 43 1 40400 4319. Fax: 43 1 40400 4845. E-mail: thomas.stulnig@akh-wien.ac.at Abbreviations used in this paper: BHT butylated hydroxy-toluene EtOH ethanol DRM detergent-resistant membrane domain GAM goat anti–mouse antibody GPI glycosyl phosphatidylinositol PUFA polyunsaturated fatty acid TCR T cell receptor Submitted: 13 May 1998 Revision received 2 September 1998

Journal

The Journal of Cell Biology – Rockefeller University Press

Published: Nov 2, 1998

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