Localization of a Band 3-related protein in the mitochondria-rich cells of amphibian skin epithelium.

Based on immunoblotting procedure, the isolated epithelium of amphibian skin was found to contain a 180 kDa protein which cross-reacts with a polyclonal antiserum raised against human erythrocyte Band 3. Immunoperoxidase and immunofluorescence staining techniques indicated that the Band 3-related protein was localized in the mitochondria-rich cells (MRC) of this epithelium, with characteristic apical labelling pattern. Our findings show that the putative apical anion exchanger of the MRC is immunologically related to the band 3 multigenic family, which catalyzes Cl(-)-HCO3- transmembranous exchange. It thus suggests a molecular basis for the role played by these cells in the transepithelial Cl- pathway and acid-base regulation.