Seeing cellular sialidase transform sugars

Abstract

Cell-surface carbohydrates are synthesized in a step-wise fashion, yielding products with unique capping structures. A recent study has shown that carbohydrates at the cell surface can be further remodeled by an endogenous glycosidase to alter the carbohydrate structure, thus generating a new function.

Figure 1

Biosynthetic pathway of mucin-like O-glycans. Once mucin-type O-glycans are synthesized in the Golgi by glycosyltransferases (GTs), the corresponding mucin-like glycoproteins are transported to the plasma membrane. Gadhoum and Sackstein showed that CD15s (sLe^x) on mucin-type glycoproteins is further subjected to processing by an endogenous sialidase on the cell surface, thus forming CD15 (Le^x). Proteins are shown in light blue.