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A Role for Caveolin in Transport of Cholesterol from Endoplasmic Reticulum to Plasma Membrane
Caveolin is a 22-kDa membrane protein found associated with a coat material decorating the inner membrane surface of caveolae. A remarkable feature of this protein is its ability to migrate from caveolae directly to the endoplasmic reticulum (ER) when membrane cholesterol is oxidized. We now present...
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Published in: | The Journal of biological chemistry 1996-11, Vol.271 (46), p.29427-29435 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Caveolin is a 22-kDa membrane protein found associated with a coat material decorating the inner membrane surface of caveolae.
A remarkable feature of this protein is its ability to migrate from caveolae directly to the endoplasmic reticulum (ER) when
membrane cholesterol is oxidized. We now present evidence caveolin is involved in transporting newly synthesized cholesterol
from the ER directly to caveolae. MA104 cells and normal human fibroblasts transported new cholesterol to caveolae with a
half-time of â¼10 min. The cholesterol then rapidly flowed from caveolae to non-caveolae membrane. Cholesterol moved out of
caveolae even when the supply of fresh cholesterol from the ER was interrupted. Treatment of cells with 10 μg/ml progesterone
blocked cholesterol movement from ER to caveolae. Simultaneously, caveolin accumulated in the lumen of the ER, suggesting
cholesterol transport is linked to caveolin movement. Caveolae fractions from cells expressing caveolin were enriched in cholesterol
3-4-fold, while the same fractions from cells lacking caveolin were not enriched. Cholesterol transport to the cell surface
was nearly 4 times more rapid in cells expressing caveolin than in matched cells lacking caveolin. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.271.46.29427 |