THE ERYTHROCYTE ANION TRANSPORTER (BAND-3)

Band 3 is the best characterized member of a multi-gene anion exchanger family. Multiple promoters within each gene produce a variety of tissue-specific transcripts. The cell-surface expression of band 3 in oocytes is promoted by glycophorin A, which might act as a molecular chaperone. Several band 3 variants have been characterized, including a transport-defective form found in ovalocytic erythrocytes that contains a nine-amino-acid deletion bordering the membrane domain. The roles of the various oligomeric forms of band 3 and interactions between band 3 subunits and between the cytosolic and membrane domains continue to draw the attention of many researchers. The recent production of two-dimensional crystalline arrays of band 3 provides hope that the vast amount of kinetic, biophysical and chemical information available on this transport system will soon be put on a firm structural footing.