Effect of gangliosides on the distribution of a glycosyl phosphatidylinositol-anchored protein in plasma membrane from CHO-K1 Cells

CRESPO P. M; ZURITA A. R.; DANIOTTI J.L

JOURNAL OF BIOLOGICAL CHEMISTRY

Año: 2002 vol. 277 p. 44731 - 44739

0021-9258

Glycosylphosphatidylinositol (GPI)-anchored proteins are mainly clustered in sphingolipid-cholesterol microdomains of the plasma membrane. The distribution of a GPI-anchored fusion protein (GPI-YFP) in the plasma membrane of CHO-K1 cells with different glycolipid compositions was investigated. Cells depleted of glycosphingolipids by inhibiting glucosylceramide synthase activity, or cell lines expressing different gangliosides due to stable transfection of appropriate ganglioside glycosyltransferases, or exposed to exogenous GM1, were transfected with GPI-YFP cDNA. The distribution of GPI-YFP fusion protein expressed at the plasma membrane was studied using the membrane-impermeable crosslinking agent bis(sulphosuccinimidyl)suberate (BS3). Results indicate that GPI-YFP form clusters at the surface of cell expressing GM3, or cells depleted of glycolipids, or transfected cells expressing mainly GD3 and GT3, or GM1 and GD1a, or mostly GM2, or highly expressing GM1. However, no significant changes in membrane microdomains of GPI-YFP were detected in the different glycolipid environment provided by the membranes of the cell lines under study. On the other hand, wild type CHO-K1 cells exposed to 100 mM of GM1 before crosslinking with BS3 showed a dramatic reduction in the amount of GPI-YFP clusters. These finding clearly indicate that manipulating the glycolipid content of cellular membrane, just by changing the ganglioside biosynthetic activity of the cell, did not significantly affect the association of GPI-YFP on the cell surface of CHO-K1 cells. The effect of exogenous GM1 gangliosides on GPI-YFP plasma membrane distribution might be a consequence of ganglioside level reached in plasma membrane and/or the effect of particular ganglioside species (micelles) that leads to membrane architecture and/or dynamic modifications.