Band 3 protein: structure, flexibility and function.
The electroneutral exchange of chloride and bicarbonate across the human erythrocyte membrane is facilitated by Band 3, a 911 amino acid glycoprotein. The 43 kDa amino-terminal cytosolic domain binds the cytoskeleton, haemoglobin and glycolytic enzymes. The 52 kDa carboxyl-terminal membrane domain mediates anion transport. The protein is a functional dimer, in which the two subunits probably interact with one another by an allosteric mechanism. It is proposed that the link between the mobile cytoplasmic and the membrane-spanning domains of the protein is flexible, based on recent biochemical, biophysical and structural data. This explains the long-standing puzzle that attachment to the cytoskeletal spectrin and actin does not appear to restrict the rotational movement of the Band 3 protein in the erythrocyte membrane. In the Band 3 isoform from the Southeast Asian Ovalocytes (SAO) this link is altered, resulting a tighter attachment of the cytoskeleton to the plasma membrane and a more rigid red blood cell.
Wang
D N
DN
European Molecular Biology Laboratory, Heidelberg, Germany.
D000494:Allosteric Regulation; D001457:Anion Exchange Protein 1, Erythrocyte / Q000737:chemistry* / Q000502:physiology*; D001210:Asia, Southeastern; D003599:Cytoskeleton / Q000737:chemistry; D004612:Elliptocytosis, Hereditary / Q000097:blood; D006801:Humans; D007091:Image Processing, Computer-Assisted; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000737:chemistry
D001457:Anion Exchange Protein 1, Erythrocyte; D046911:Macromolecular Substances; D008565:Membrane Proteins