Temporal synthesis of band 3 oligomers during terminal maturation of mouse erythroblasts. Dimers and tetramers exist in the membrane as preformed stable species

Band 3, the anion transport protein of the erythrocyte membrane, exists in the membrane as a mixture of dimers (B3D) and tetramers (B3T). The dimers are not linked to the skeleton and constitute the free mobile band 3 fraction. The tetramers are linked to the skeleton by their interaction with ankyrin. In this report we have examined the temporal synthesis and assembly of band 3 oligomers into the plasma membrane during red cell maturation. The oligomeric state of newly synthesized band 3 in early and late erythroblasts was analyzed by size-exclusion high-pressure liquid chroma-tography of band 3 extracts derived by mild extraction of plasma membranes with the nonionic detergent C12E8 (oc-taethylene glycol n-dodecyl monoether). This analysis re-vealed that at the early erythroblast stage, the newly synthe-sized band 3 is present predominantly as tetramers, wherea