| Autor: |
Weerth SH; Section for Cell Biology and Signal Transduction, National Institute of Child Health and Human Development, National Institute of Health, Bethesda, MD 20892-4480, USA., Holtzclaw LA, Russell JT |
| Jazyk: |
angličtina |
| Zdroj: |
Cell calcium [Cell Calcium] 2007 Feb; Vol. 41 (2), pp. 155-67. Date of Electronic Publication: 2006 Aug 14. |
| DOI: |
10.1016/j.ceca.2006.06.006 |
| Abstrakt: |
The hypothesis that calcium signaling proteins segregate into lipid raft-like microdomains was tested in isolated membranes of rat oligodendrocyte progenitor (OP) cells and astrocytes using Triton X-100 solubilization and density gradient centrifugation. Western blot analysis of gradient fractions showed co-localization of caveolin-1 with proteins involved in the Ca2+ signaling cascade. These included agonist receptors, P2Y1, and M1, TRPC1, IP3R2, ryanodine receptor, as well as the G protein Galphaq and Homer. Membranes isolated from agonist-stimulated astrocytes showed an enhanced recruitment of phospholipase C (PLCbeta1), IP3R2 and protein kinase C (PKC-alpha) into lipid raft fractions. IP3R2, TRPC1 and Homer co-immunoprecipitated, suggesting protein-protein interactions. Disruption of rafts by cholesterol depletion using methyl-beta-cyclodextrin (beta-MCD) altered the distribution of caveolin-1 and GM1 to non-raft fractions with higher densities. beta-MCD-induced disruption of rafts inhibited agonist-evoked Ca2+ wave propagation in astrocytes and attenuated wave speeds. These results indicate that in glial cells, Ca2+ signaling proteins might exist in organized membrane microdomains, and these complexes may include proteins from different cellular membrane systems. Such an organization is essential for Ca2+ wave propagation. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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