Recent Advances in the Study of Glycosphingolipids

Glycosphingolipids (GSLs) are present in all mammalian cell plasma membranes and intracellular membrane structures. They are especially concentrated in plasma membrane lipid domains that are specialized for cell signaling. Plasma membranes show typical structures called rafts and caveola domain structures, with large amounts of sphingolipids, cholesterol, and sphingomyelin in the cell membranes. Plasma membranes have two faces, many kinds of receptors for intercellular signal transducers such as GPI-anchored proteins on the exoplasmic faces of the rafts/caveolae and src family kinases on the cytosolic face. Thus they play a role in transmembrane signal transduction, following the phosphorylation of some substrates and gene expression. On the other hand, their functions have become clear through the study of gene-manipulated mice. For further advances, a visual method to display diversity of biological functions is necessary. For this purpose, the use of high-performance microscopes and live cell imaging technologies are useful for more detailed understanding.