Figure 3

Factors that impinge on oligosaccharide biosynthesis and result in altered cell surface glycan display. (a) Endogenous regulation, in concert with external signaling events, can result in different forms (illustrated by 1 and 2) of cell-surface oligosaccharide expression. (b) Disease states are often characterized by specific, and in some cases multiple, changes in glycosylation that can be attributed to abnormalities in the metabolic pathways involved in oligosaccharide biosynthesis. (c) External inputs, such as exogenously delivered metabolites, in addition to the previously mentioned signaling events, can modulate cell-surface glycan composition.