9-O-acetyl GD3 in lymphoid and erythroid cells

Abstract

Sialic acids are electronegatively charged sugars that contribute to the enormous structural diversity of complex carbohydrates, which are major constituents of mostly proteins and lipids of cell membranes and secreted macromolecules. They are usually positioned at the outer end of these molecules and thus are well suited for interacting with other cells, pathogens, or molecules in the cell environment. Sialic acids are 9-carbon-containing monosaccharides, and the structural diversity of glycan chains is further increased by the various modifications of sialic acids [1]. Amongst 50 known derivatives of sialic acids, 7-, 8-, and 9-O-acetylated derivatives (O-AcSA) are important constituents of the cell membrane and are known to influence many physiological and pathological processes [1, 2], including cell-cell adhesion, signaling, differentiation, and metastasis [3-6]. However, as O-acetyl esters from positions C-7 and C-8 spontaneously migrate to C-9, even under physiologic conditions, O-acetylation at C-9 is considered the most common biologically occurring modification [7]. The appearance of O-acetylated sialic acids on glycoproteins or glycolipids is cell-type specific and developmentally regulated, their synthesis and turnover being a highly orchestrated phenomenon. O-acetylation can have a significant role in cell physiology and can alter the functional effects of important molecular determinants in various disease conditions. In this chapter, we deal with the O-acetylation of glycosphingolipids (GSLs), specifically GD3 in both erythroid and lymphoid cells. © 2011 Springer Science+Business Media, LLC.