グリオーマ細胞糖脂質抗原のcrypticity機構の解析とその生物学的意義に関する検討
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概要
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We have already reported the cell density regulation of crypticity of gangliosides in human glioma cells. In the present study, we studied the mechanisms of the crypticity and discussed the biological significance of the ganglioside crypticity phenomenon. The glioma cell line used was A172, which contains GM2 ganglioside as its sole ganglioside. A higher antibody reactivity was obtained in FACS analysis by treating the confluent cells with saponin for membrane permeabilization. This indicated that the cryptic gangliosides also existed on the surface of the plasma membrane. Immunoelectronmicroscopic studies revealed that many micro invaginations and pits were aligned along the plasma membrane, and GM2 gangliosides were distributed in these structures. Inhibition of caveolae formation with filipin almost fully exposed cryptic GM2 gangliosides of confluent cells. Western blotting revealed 'caveolin', which is caveolae specific protein, in A172 cells. These results revealed that these invaginations of the plasma membrane were actually the caveolae and that the mechanism of crypticity of gangliosides was regulated by these microdomains. Recently, many functions have been ascribed to caveolae, where such proteins as glycosylphosphatidylinositol (GPI)-anchored proteins and low molecular G protein are concentrated, such as transcytosis, potocytosis, and transmembrane signal transduction. Crosslinking SDS-PAGE analysis showed GM2 ganglioside in the caveolae associated with particular proteins. These proteins may possibly play significant roles in cell-to-cell interactions, or signal transduction.
- 札幌医科大学の論文
- 1998-12-01