Terminal glycosyltransferase activity: a selective role in cell adhesion

FOR DECADES, knowledge about blood group antigens has constituted the basis for sound transfusion practice. Although blood group serology may seem a research area largely restricted to the surface antigens on human red blood cells (and platelets), many of the known blood group antigens have a far broader tissue expression than generally acknowledged. The ABO blood group system, discovered in 1900 by Karl Landsteiner, is, for instance, also found on other cell types (mainly of epithelial origin) and evolves even earlier in these tissues than on erythrocytes. The specificity of many (histo-)blood group antigens relies on subtle differences in sugar components linked to membrane lipids and/or proteins. Hence, a great deal of biochemical insight in glycosyltransferase function (eg, optimal conditions for enzymatic activity, substrate requirements, and product formation) has been generated in relation to the carbohydrate antigens on erythrocytes. Although sugar determinants resulting from enzymatic transfer of L-fucose residues are of relatively minor importance for transfusion medicine, this review will show that recent discoveries in the adhesion field warrant a better understanding of the fucosyltransferase (FT) (sub)types and their tissue-restricted expression pattern with respect to inflammatory responses and lymphocyte traffic.