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Caveolin-1 alters the pattern of cytoplasmic Ca2+ oscillations and Ca2+-dependent gene expression by enhancing leukotriene receptor desensitization.

Yeh YC, Tang MJ, Parekh AB - J. Biol. Chem. (2014)

Bottom Line: Here, we show that the scaffolding protein caveolin-1 has a profound effect on receptor-driven Ca(2+) signals and downstream gene expression.Mutagenesis studies revealed that these effects required a functional scaffolding domain within caveolin-1.Our results reveal that caveolin-1 is a bimodal regulator of receptor-dependent Ca(2+) signaling, which fine-tunes the spatial and temporal profile of the Ca(2+) rise and thereby its ability to activate the NFAT pathway.

View Article: PubMed Central - PubMed

Affiliation: From the Department of Physiology, Anatomy, and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, United Kingdom and.

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Receptor-phospholipase C coupling increases in the presence of caveolin-1.A, stimulation with LTC4 increases the release of GFP-PHD from the plasma membrane when caveolin-1-RFP (Cav1) is present. B, aggregate data are summarized (9 and 13 cells for each condition on three separate preparations). C, following stimulation with LTC4 in Ca2+-free solution, the amount of Ca2+ remaining in the stores was estimated by application of thapsigargin (Thap.; 2 μm). D, aggregate data are summarized. The rate of rise of cytoplasmic Ca2+ following application of thapsigargin was measured as an indicator of the Ca2+ content of the stores. Data represent 44 caveolin-1-GFP-expressing cells and 39 wild type cells from two independent cell preparations. **, p < 0.01; ***, p < 0.001.
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Figure 3: Receptor-phospholipase C coupling increases in the presence of caveolin-1.A, stimulation with LTC4 increases the release of GFP-PHD from the plasma membrane when caveolin-1-RFP (Cav1) is present. B, aggregate data are summarized (9 and 13 cells for each condition on three separate preparations). C, following stimulation with LTC4 in Ca2+-free solution, the amount of Ca2+ remaining in the stores was estimated by application of thapsigargin (Thap.; 2 μm). D, aggregate data are summarized. The rate of rise of cytoplasmic Ca2+ following application of thapsigargin was measured as an indicator of the Ca2+ content of the stores. Data represent 44 caveolin-1-GFP-expressing cells and 39 wild type cells from two independent cell preparations. **, p < 0.01; ***, p < 0.001.

Mentions: If caveolin-1 increases receptor-phospholipase C coupling, two predictions are that, first, InsP3 levels should increase more following stimulation in the presence of caveolin-1 than in wild type cells, and second, less Ca2+ should remain within the InsP3-sensitive store after the Ca2+ oscillations have run down in cells expressing caveolin-1. Using the GFP-PHD construct as a means for monitoring InsP3 levels in individual cells (15–17), we found that stimulation with LTC4 for 5 min resulted in a modest decrease in the membrane/cytosol ratio of GFP-PHD (decrease of 24.5 ± 1.7%; Fig. 3, A and B), and this was slightly more pronounced when caveolin-1-RFP was expressed (31.2 ± 1.4%, p < 0.05; Fig. 3, A and B). To test the second prediction, we stimulated cells with LTC4 in the absence of external Ca2+, and then once the oscillations had stopped, we applied thapsigargin in Ca2+-free solution to estimate how much Ca2+ remained within the store (Fig. 3C). The thapsigargin-mobilizable Ca2+ pool was significantly reduced in cells expressing caveolin-1-GFP (Fig. 3D, p < 0.01).


Caveolin-1 alters the pattern of cytoplasmic Ca2+ oscillations and Ca2+-dependent gene expression by enhancing leukotriene receptor desensitization.

Yeh YC, Tang MJ, Parekh AB - J. Biol. Chem. (2014)

Receptor-phospholipase C coupling increases in the presence of caveolin-1.A, stimulation with LTC4 increases the release of GFP-PHD from the plasma membrane when caveolin-1-RFP (Cav1) is present. B, aggregate data are summarized (9 and 13 cells for each condition on three separate preparations). C, following stimulation with LTC4 in Ca2+-free solution, the amount of Ca2+ remaining in the stores was estimated by application of thapsigargin (Thap.; 2 μm). D, aggregate data are summarized. The rate of rise of cytoplasmic Ca2+ following application of thapsigargin was measured as an indicator of the Ca2+ content of the stores. Data represent 44 caveolin-1-GFP-expressing cells and 39 wild type cells from two independent cell preparations. **, p < 0.01; ***, p < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4067216&req=5

Figure 3: Receptor-phospholipase C coupling increases in the presence of caveolin-1.A, stimulation with LTC4 increases the release of GFP-PHD from the plasma membrane when caveolin-1-RFP (Cav1) is present. B, aggregate data are summarized (9 and 13 cells for each condition on three separate preparations). C, following stimulation with LTC4 in Ca2+-free solution, the amount of Ca2+ remaining in the stores was estimated by application of thapsigargin (Thap.; 2 μm). D, aggregate data are summarized. The rate of rise of cytoplasmic Ca2+ following application of thapsigargin was measured as an indicator of the Ca2+ content of the stores. Data represent 44 caveolin-1-GFP-expressing cells and 39 wild type cells from two independent cell preparations. **, p < 0.01; ***, p < 0.001.
Mentions: If caveolin-1 increases receptor-phospholipase C coupling, two predictions are that, first, InsP3 levels should increase more following stimulation in the presence of caveolin-1 than in wild type cells, and second, less Ca2+ should remain within the InsP3-sensitive store after the Ca2+ oscillations have run down in cells expressing caveolin-1. Using the GFP-PHD construct as a means for monitoring InsP3 levels in individual cells (15–17), we found that stimulation with LTC4 for 5 min resulted in a modest decrease in the membrane/cytosol ratio of GFP-PHD (decrease of 24.5 ± 1.7%; Fig. 3, A and B), and this was slightly more pronounced when caveolin-1-RFP was expressed (31.2 ± 1.4%, p < 0.05; Fig. 3, A and B). To test the second prediction, we stimulated cells with LTC4 in the absence of external Ca2+, and then once the oscillations had stopped, we applied thapsigargin in Ca2+-free solution to estimate how much Ca2+ remained within the store (Fig. 3C). The thapsigargin-mobilizable Ca2+ pool was significantly reduced in cells expressing caveolin-1-GFP (Fig. 3D, p < 0.01).

Bottom Line: Here, we show that the scaffolding protein caveolin-1 has a profound effect on receptor-driven Ca(2+) signals and downstream gene expression.Mutagenesis studies revealed that these effects required a functional scaffolding domain within caveolin-1.Our results reveal that caveolin-1 is a bimodal regulator of receptor-dependent Ca(2+) signaling, which fine-tunes the spatial and temporal profile of the Ca(2+) rise and thereby its ability to activate the NFAT pathway.

View Article: PubMed Central - PubMed

Affiliation: From the Department of Physiology, Anatomy, and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, United Kingdom and.

Show MeSH