Altered band 3 structure and function in glycophorin A- and B-deficient (MkMk) red blood cells.
The anion transport activity of the human erythrocyte anion transporter (band 3; AE1) has been examined in both normal and glycophorin A (GPA)-deficient (MkMk) human red blood cells (RBCs). The sulfate transport activity of MkMk cells (from two ethnically diverse sources) was approximately 60% that of normal erythrocytes under the transport assay conditions used. However, MkMk and normal RBCs contained similar amounts of band 3. The reduction in sulfate transport activity was shown to be caused by an increase in the apparent Km for sulfate in MkMk RBCs, suggesting the band 3 in the MkMk RBCs has a lowered binding affinity for sulfate anions. The size of the N-glycan chain on band 3 of the MkMk cells was larger than that on band 3 from normal RBCs. In contrast, the size of the N-glycan chain on the glucose transporter (GLUT1) from MkMk cells was smaller than that on GLUT1 from normal cells. The possible role of GPA in the biosynthesis and anion transport activity of band 3 in normal RBCs is discussed.
Bruce
L J
LJ
Department of Biochemistry, School of Medical Sciences, University of Bristol, UK.
Groves
J D
JD
Okubo
Y
Y
Thilaganathan
B
B
Tanner
M J
MJ
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000378:metabolism / Q000494:pharmacology; D001457:Anion Exchange Protein 1, Erythrocyte / Q000737:chemistry / Q000378:metabolism*; D001692:Biological Transport; D004910:Erythrocyte Membrane / Q000378:metabolism*; D051272:Glucose Transporter Type 1; D006021:Glycophorins / Q000172:deficiency*; D006801:Humans; D066298:In Vitro Techniques; D008951:MNSs Blood-Group System; D009004:Monosaccharide Transport Proteins / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry; D013431:Sulfates / Q000378:metabolism
D001457:Anion Exchange Protein 1, Erythrocyte; D051272:Glucose Transporter Type 1; D006021:Glycophorins; D008951:MNSs Blood-Group System; D009004:Monosaccharide Transport Proteins; D011134:Polysaccharides; C495677:SLC2A1 protein, human; D013431:Sulfates; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid