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Microdomains of GPI-anchored proteins in living cells revealed by crosslinking

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Item Type:Article
Title:Microdomains of GPI-anchored proteins in living cells revealed by crosslinking
Creators Name:Friedrichson, T. and Kurzchalia, T.V.
Abstract:There is some discussion as to whether glycosyl-phosphatidylinositol(GPI)-anchored proteins occur in microdomains in the cell membrane. These putative microdomains have been implicated in processes such as sorting in polarized cells and signal transduction. Complexes enriched in GPI-anchored proteins, cholesterol and glycosphingolipids have been isolated from cell membranes by using non-ionic detergents: these complexes were thought to represent a clustered arrangement of GPI-anchored proteins. However, results obtained when clustering of GPI-anchored proteins induced by antibodies or by detergents was prevented support the idea of a dispersed surface distribution of GPI-anchored proteins at steady state. Here we use chemical crosslinking to show that membrane microdomains of a GPI-anchored protein exist at the surface in living cells. This clustering is specific for the GPI-anchored form, as two transmembrane forms bearing the same ectodomain do not form oligomers. Depletion of membrane cholesterol causes the clustering of GPI-anchored proteins to break up, whereas treatment of cells with detergent substantially increases the size of the complexes. We find that in living cells these GPI-anchored proteins reside in microdomains consisting of at least 15 molecules, which are much smaller than those seen after detergent extraction.
Keywords:CD55 Antigens, CHO Cells, Cell Line, Cell Membrane, Cross-Linking Reagents, Detergents, Glycosylphosphatidylinositols, Growth Hormone, Molecular Cloning, Animals, Cricetinae, Rats
Publisher:Nature Publishing Group
Page Range:802-805
Date:20 August 1998
Official Publication:https://doi.org/10.1038/29570
PubMed:View item in PubMed

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