Structure-function relationships of band 3 variants.

This review describes many of the naturally occurring band 3 variants that have been reported in the literature to date; from the common band 3 Memphis, to the rare band 3 HT. Both the molecular basis of these variants, and their effect on the structure and/or function of band 3, are described. The blood group antigens that have recently been assigned to band 3, such as Diego, Wright, Waldner, Redelberger and Warrior, are mentioned. Band 3 variants that affect the morphology of the red cell (e.g. acanthocytosis in band 3 HT and stomatocytic ovalocytosis in band 3 SAO) are described, as are many of the band 3 mutations that cause instability, either at the mRNA or protein level, and hence hereditary spherocytosis (HS). Band 3 variants that affect the binding pocket of the anion transport inhibitor, 4,4'-diisothiocyanato-2,2'-dihydrostilbene disulphonic acid (H2DIDS), (e.g. Diego and band 3 HT) and band 3 variants that affect the rate of anion transport (e.g. band 3 HT and band 3 in red cells that lack glycophorin A (GPA)) are reviewed in greater detail. The association between band 3 and GPA is discussed; both with respect to the Wright antigens and with regards the structure/function of band 3 in the absence of GPA.