Effects of plasma glycosyltransferase on the ABO(H) blood group antigens of human von Willebrand factor
Von Willebrand factor (VWF) is one of the plasma protein carrying ABO(H) blood group antigens, but the combining process of these antigens is not clear. In the present study, we examined whether plasma glycosyltransferase affects the blood group antigens on VWF. VWF expressing H-antigen (H-VWF) from blood group O and bovine serum albumin conjugated with H-antigen (H-BSA) were incubated with recombinant α1-3-N-acetylgalactosaminyltransferase (rA-transferase) and A-plasma with or without an additional UDP-GalNAc. Transformed antigens were detected by western blotting and ELISA, using an anti-A antibody. Both H-VWF and H-BSA acquired the A-antigen after incubation with rA-transferase and UDP-GalNAc. Incubation with A-plasma very weakly converted the H-antigen on BSA and VWF to A-antigen only in the presence of supplemented UDP-GalNAc. This conversion was enhanced on desialylation of H-VWF. These results indicate that sugar chains of plasma VWF can be modified by the external glycosyltransferase, but that plasma glycosyltransferase has no effect on the blood group antigens of VWF due to its low activity and the lack of donor sugars. Further, sialic acid residues of VWF may exert a protective effect against post-translational glycosylation. Our results clearly exclude the possibility that blood group antigens of VWF are constructed extracellularly in plasma.
Keywordsvon Willebrand factor ABO blood group Plasma Glycosyltransferase Sugar nucleotide
This work was supported by Grant-in-Aid for Scientific Research (C) (Grant number 25461463 to TM) from the Japan Society for the Promotion of Science.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- 17.O’Donnell J, Boulton FE, Manning RA, Laffan MA. Amount of H antigen expressed on circulating von Willebrand factor is modified by ABO blood group genotype and is a major determinant of plasma von Willebrand factor antigen levels. Arterioscler Thromb Vasc Biol. 2002;22:335–41.CrossRefPubMedGoogle Scholar
- 27.Whitehead JS, Bella A Jr, Kim YS. An N-acetylgalactosaminyltransferase from human blood group A plasma I. Purification and agarose binding properties. J Biol Chem. 1974;249:3442–7.Google Scholar
- 29.Matsumoto M, Kawaguchi S, Ishizashi H, Yagi H, Iida J, Sakaki T, et al. Platelets treated with ticlopidine are less reactive to unusually large von Willebrand factor multimers than are those treated with aspirin under high shear stress. Pathophysiol Haemost Thromb. 2005;34(1):35–40.CrossRefPubMedGoogle Scholar