Band 3 glycoprotein and glycophorin A from erythrocytes of children with congenital disorder of glycosylation type-Ia are underglycosylated.
Band 3 and PAS-1 (a dimer of glycophorin A) from erythrocyte membranes of three children with congenital disorder of glycosylation, type Ia (CDG-Ia), aged 1 month, 3 years and 10 years respectively, were examined by a new technique that allowed determination of carbohydrate molar composition of glycoproteins separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. In CDG children a single N-glycan of band 3 glycoprotein was hypoglycosylated and its mannose content was normal or elevated. Glycophorin A which is the major carrier of erythrocyte sialic acid, was deficient in N-acetylgalactosamine, and sialic acid residues. This finding indicated a partial unglycosylation of O-glycans in glycophorin A. In keeping with the results of PAS-1 analysis, total sialic acid in erythrocyte membranes from CDG children was reduced to 40-56% of normal values. A possible molecular mechanism of hypo- and unglycosylation of band 3 and glycophorin A, respectively, in CDG is discussed.
Zdebska
E
E
Department of Biochemistry, Institute of Hematology and Blood Transfusion, ul. Chocimska 5, 00-957 Warsaw, Poland.
Musielak
M
M
Jaeken
J
J
Kościelak
J
J
D001457:Anion Exchange Protein 1, Erythrocyte / Q000737:chemistry*; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D018981:Congenital Disorders of Glycosylation / Q000097:blood* / Q000145:classification / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D004910:Erythrocyte Membrane / Q000737:chemistry; D006021:Glycophorins / Q000737:chemistry*; D006031:Glycosylation; D006801:Humans; D007223:Infant; D008969:Molecular Sequence Data; D019158:N-Acetylneuraminic Acid / Q000032:analysis; D020543:Proteome; D012967:Sodium Dodecyl Sulfate
D001457:Anion Exchange Protein 1, Erythrocyte; D002241:Carbohydrates; D006021:Glycophorins; D020543:Proteome; D012967:Sodium Dodecyl Sulfate; D019158:N-Acetylneuraminic Acid