Cholesterol depletion perturbs calcium handling by rat submandibular glands
| Autor: | Aida Marino, Alain Kumps, Séverine Tandel, Mikel Garcia-Marcos, Jean-Paul Dehaye, Françoise Gomez, J. Genin, M. De Lorenzi, Stéphanie Pochet |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Intracellular Fluid
Male Thapsigargin Octoxynol Physiology Caveolin 1 Submandibular Gland Clinical Biochemistry Population Down-Regulation chemistry.chemical_element Calcium Caveolins chemistry.chemical_compound Sodium fluoride Extracellular Animals Calcium Signaling Rats Wistar education education.field_of_study Phospholipase C Calcium channel Cell Membrane beta-Cyclodextrins Epithelial Cells Extracellular Fluid Cell Biology Rats Cholesterol chemistry Biochemistry Type C Phospholipases GTP-Binding Protein alpha Subunits Gq-G11 Calcium Channels Subcellular Fractions Homogenization (biology) |
| Zdroj: | Journal of Cellular Physiology. 203:429-438 |
| ISSN: | 1097-4652 0021-9541 |
| DOI: | 10.1002/jcp.20241 |
| Popis: | The sensitivity to cholesterol depletion of calcium handling by rat submandibular glands was investigated. The glands were digested with collagenase. After homogenization, the lysate was extracted at 4 degrees C with 0.5% Triton X-100 and the extract was submitted to an ultracentrifugation in a sucrose discontinuous gradient. A population of detergent-resistant membranes (DRM) was collected at the 5%-35% interface. The DRM had a higher content of cholesterol, saturated and long-chain fatty acids. Caveolin-1 and alpha(q/11) were located in these membranes. They were more ordered than vesicles from total cellular lysate as determined by anisotropy measurement. They disappeared after cholesterol extraction with methyl-beta-cyclodextrin (MCD). Exposure of the cellular suspension with MCD nearly abolished the response to carbachol, epinephrine, and substance P and inhibited the activation of phospholipase C (PLC) by these agonists and by sodium fluoride. MCD did not affect the mobilization of intracellular pools of calcium by thapsigargin. It increased the uptake of extracellular calcium or barium and did not inhibit the uptake of calcium after depletion of the intracellular stores of this ion. From these results, it is concluded that Triton X-100 can extract a fraction of membrane resistant to detergents. Treatment of the cells with MCD disrupts these membranes. The coupling between the heterotrimeric GTP-binding protein G(q/11) and poly-phosphoinositide-specific PLC is affected by disruption of these membrane fractions. At the opposite, the store-operated calcium channel (SOCC) is not affected by DRM-disruption. |
| Databáze: | OpenAIRE |
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