ANION-EXCHANGER-2 (AE2) BINDS TO ERYTHROCYTE ANKYRIN AND IS COLOCALIZED WITH ANKYRIN ALONG THE BASOLATERAL PLASMA-MEMBRANE OF HUMAN GASTRICPARIETAL-CELLS

The hydrochloric acid secreting parietal cells of the human stomach mu cosa have been shown to express anion exchanger 2 (AE2). AE2 is restri cted to the basolateral membrane domain and is responsible for the bas olateral uptake of Cl- and release of HCO3-. It is unknown which mecha nism is responsible for the basolateral positioning of AE2 in parietal cells. We raised the question whether AE2 might be immobilized at the cell surface by linkage via ankyrin to the spectrin/actin-based membr ane cytoskeleton. In the present study we communicate two observations that support this hypothesis, namely that in parietal cells ankyrin i s localized with AE2 along the basolateral cell surface and, secondly, that purified erythrocyte ankyrin binds to the in vitro-translated cy toplasmic domain of AE2. We conclude from these observations that AE2 in parietal cells might be linked via ankyrin to the basolateral membr ane cytoskeleton and that this type of linkage might play a role in im mobilizing AE2 in a non-random fashion along the basolateral membrane domain.