The diversity of carbohydrate structures both amazes and overwhelms us, as does the diversity of the enzymes that are responsible for their synthesis. Cells express only a limited subset of the glycosyltransferases and glycosidases that are available to them, and do so in tissue-specific and spatiallyspecific patterns. In this regard, how particular enzymatic components of the glycosylation apparatus become and remain segregated in specific subcellular organelles is a question that impacts on issues ranging from cell biology to pharmaceutical development. Clearly, amino acid sequences contained within and adjacent to the transmembrane domain are responsible, at least in part, for the selective retention of specific glycosyltransferases to the Golgi compartments. The specific amino acid residues that are required, and how they cooperate with cytosolic proteins to localize unique glycosyltransferases to defined membrane organelles continues to be an area of intense study [1—3]. Compounding this complexity of glycosyltransferase expression, are studies that show that some glycosyltransferases are localized on the plasma membrane in addition to their conventional Golgi location [4, 5]. This prompted the hypothesis that glycosyltransferases may function as cell adhesion molecules by binding their complementary