The Experts below are selected from a list of 40563 Experts worldwide ranked by ideXlab platform

Preston R Mason - One of the best experts on this subject based on the ideXlab platform.

Samuel C R Sherratt - One of the best experts on this subject based on the ideXlab platform.

W Waldhausl - One of the best experts on this subject based on the ideXlab platform.

  • polyunsaturated Eicosapentaenoic Acid displaces proteins from membrane rafts by altering raft lipid composition
    Journal of Biological Chemistry, 2001
    Co-Authors: Thomas M Stulnig, Joakim Huber, Norbert Leitinger, Esthermaria Imre, Pavla Angelisova, P Nowotny, W Waldhausl
    Abstract:

    Polyunsaturated fatty Acids (PUFAs) such as Eicosapentaenoic Acid (20:5 (n-3)) inhibit T lymphocyte activation probably by displacing acylated signaling proteins from membrane lipid rafts. Under physiological conditions, saturated fatty acyl residues of such proteins partition into the cytoplasmic membrane lipid leaflet with high affinity for rafts that are enriched in saturated fatty acyl-containing lipids. However, the biochemical alteration causing displacement of acylated proteins from rafts in PUFA-treated T cells is still under debate but could principally be attributed to altered protein acylation or changes in raft lipid composition. We show that treatment of Jurkat T cells with polyunsaturated Eicosapentaenoic Acid (20:5 (n-3)) results in marked enrichment of PUFAs (20:5; 22:5) in lipids from isolated rafts. Moreover, PUFAs were significantly incorporated into phosphatidylethanolamine that predominantly resides in the cytoplasmic membrane lipid leaflet. Notably, palmitate-labeled Src family kinase Lck and the linker for activation of T cells (LAT) were both displaced from lipid rafts indicating that acylation by PUFAs is not required for protein displacement from rafts in PUFA-treated T cells. In conclusion, these data provide strong evidence that displacement of acylated proteins from rafts in PUFA-treated T cells is predominantly due to altered raft lipid composition.

Michael L. Tuck - One of the best experts on this subject based on the ideXlab platform.

  • Eicosapentaenoic Acid inhibits Ca2+ mobilization and PKC activityin vascular smooth muscle cells
    American Journal of Hypertension, 2003
    Co-Authors: Michael D. Nyby, Mark T. Hori, Bernard L. Ormsby, Ara Gabrielian, Michael L. Tuck
    Abstract:

    Abstract Background Eicosapentaenoic Acid is a fish oil fatty Acid that has been shown to decrease blood pressure (BP) in humans. The mechanism by which this fatty Acid produces this effect is unknown. Angiotensin II increases BP by inducing vasoconstriction of vascular smooth muscle cells, an event that is mediated by an increase of intracellular calcium and an increase of protein kinase C activity. Methods We determined the effects of Eicosapentaenoic Acid on angiotensin II-induced calcium signaling, and protein kinase C activity in cultured rat aortic smooth muscle cells. Incorporation of Eicosapentaenoic Acid into cell phospholipids was determined by gas chromatography/mass spectrometry. Intracellular calcium concentration was determined using fura-2, and protein kinase C activity was assessed by an ELISA assay using a phospho-specific antiserum for protein kinase C substrates. Results We found that Eicosapentaenoic Acid was incorporated into cell phospholipids within 20 min. Eicosapentaenoic Acid (10 or 25 μmol/L) did not alter basal intracellular calcium concentration, but decreased the peak response to 100 nmol/L angiotensin II. Eicosapentaenoic Acid also decreased the amount of calcium released by thapsigargin, a drug that releases calcium from the sarcoplasmic reticulum, and decreased cation influx after angiotensin II stimulation. Angiotensin II stimulated phosphorylation of protein kinase C substrates. Preincubation of cells with 10 or 25 μmol/L Eicosapentaenoic Acid significantly inhibited this phosphorylation. Conclusions Our results demonstrate that acute incorporation of Eicosapentaenoic Acid into vascular smooth muscle cell phospholipids inhibits intracellular calcium mobilization and protein kinase C activation. These are potential mechanisms by which Eicosapentaenoic Acid reduces vasoconstriction.

  • Eicosapentaenoic Acid inhibits Ca2+ mobilization and PKC activity in vascular smooth muscle cells.
    American journal of hypertension, 2003
    Co-Authors: Michael D. Nyby, Mark T. Hori, Bernard L. Ormsby, Ara Gabrielian, Michael L. Tuck
    Abstract:

    Eicosapentaenoic Acid is a fish oil fatty Acid that has been shown to decrease blood pressure (BP) in humans. The mechanism by which this fatty Acid produces this effect is unknown. Angiotensin II increases BP by inducing vasoconstriction of vascular smooth muscle cells, an event that is mediated by an increase of intracellular calcium and an increase of protein kinase C activity. We determined the effects of Eicosapentaenoic Acid on angiotensin II-induced calcium signaling, and protein kinase C activity in cultured rat aortic smooth muscle cells. Incorporation of Eicosapentaenoic Acid into cell phospholipids was determined by gas chromatography/mass spectrometry. Intracellular calcium concentration was determined using fura-2, and protein kinase C activity was assessed by an ELISA assay using a phospho-specific antiserum for protein kinase C substrates. We found that Eicosapentaenoic Acid was incorporated into cell phospholipids within 20 min. Eicosapentaenoic Acid (10 or 25 micromol/L) did not alter basal intracellular calcium concentration, but decreased the peak response to 100 nmol/L angiotensin II. Eicosapentaenoic Acid also decreased the amount of calcium released by thapsigargin, a drug that releases calcium from the sarcoplasmic reticulum, and decreased cation influx after angiotensin II stimulation. Angiotensin II stimulated phosphorylation of protein kinase C substrates. Preincubation of cells with 10 or 25 micromol/L Eicosapentaenoic Acid significantly inhibited this phosphorylation. Our results demonstrate that acute incorporation of Eicosapentaenoic Acid into vascular smooth muscle cell phospholipids inhibits intracellular calcium mobilization and protein kinase C activation. These are potential mechanisms by which Eicosapentaenoic Acid reduces vasoconstriction.

Thomas M Stulnig - One of the best experts on this subject based on the ideXlab platform.

  • polyunsaturated Eicosapentaenoic Acid displaces proteins from membrane rafts by altering raft lipid composition
    Journal of Biological Chemistry, 2001
    Co-Authors: Thomas M Stulnig, Joakim Huber, Norbert Leitinger, Esthermaria Imre, Pavla Angelisova, P Nowotny, W Waldhausl
    Abstract:

    Polyunsaturated fatty Acids (PUFAs) such as Eicosapentaenoic Acid (20:5 (n-3)) inhibit T lymphocyte activation probably by displacing acylated signaling proteins from membrane lipid rafts. Under physiological conditions, saturated fatty acyl residues of such proteins partition into the cytoplasmic membrane lipid leaflet with high affinity for rafts that are enriched in saturated fatty acyl-containing lipids. However, the biochemical alteration causing displacement of acylated proteins from rafts in PUFA-treated T cells is still under debate but could principally be attributed to altered protein acylation or changes in raft lipid composition. We show that treatment of Jurkat T cells with polyunsaturated Eicosapentaenoic Acid (20:5 (n-3)) results in marked enrichment of PUFAs (20:5; 22:5) in lipids from isolated rafts. Moreover, PUFAs were significantly incorporated into phosphatidylethanolamine that predominantly resides in the cytoplasmic membrane lipid leaflet. Notably, palmitate-labeled Src family kinase Lck and the linker for activation of T cells (LAT) were both displaced from lipid rafts indicating that acylation by PUFAs is not required for protein displacement from rafts in PUFA-treated T cells. In conclusion, these data provide strong evidence that displacement of acylated proteins from rafts in PUFA-treated T cells is predominantly due to altered raft lipid composition.