Osmotic Stress Reduces Ca2+ Signals through Deformation of Caveolae
| Autor: | Yuanjian Guo, Katrina Haught, Lu Yang, Suzanne Scarlata |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Osmotic shock
Osmotic concentration biology G protein Caveolin 1 chemistry.chemical_element Cell Biology Calcium Phospholipase Caveolae Biochemistry Cell biology Rats chemistry Gq alpha subunit Osmotic Pressure Caveolin biology.protein Animals GTP-Binding Protein alpha Subunits Gq-G11 Calcium Signaling Molecular Biology Signal Transduction |
| Zdroj: | The Journal of biological chemistry. 290(27) |
| ISSN: | 1083-351X |
| Popis: | Caveolae are membrane invaginations that can sequester various signaling proteins. Caveolae have been shown to provide mechanical strength to cells by flattening to accommodate increased volume when cells are subjected to hypo-osmotic stress. We have previously found that caveolin, the main structural component of caveolae, specifically binds Gαq and stabilizes its activation state resulting in an enhanced Ca(2+) signal upon activation. Here, we show that osmotic stress caused by decreasing the osmolarity in half reversibly changes the configuration of caveolae without releasing a significant portion of caveolin molecules. This change in configuration due to flattening leads to a loss in Cav1-Gαq association. This loss in Gαq/Cav1 association due to osmotic stress results in a significant reduction of Gαq/phospholipase Cβ-mediated Ca(2+) signals. This reduced Ca(2+) response is also seen when caveolae are reduced by treatment with siRNA(Cav1) or by dissolving them by methyl-β-cyclodextran. No change in Ca(2+) release with osmotic swelling can be seen when growth factor pathways are activated. Taken together, these results connect the mechanical deformation of caveolae to Gαq-mediated Ca(2+) signals. |
| Databáze: | OpenAIRE |
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