The α-Subunit of the Colonic H+,K+-ATPase Assembles with β1-Na+,K+-ATPase in Kidney and Distal Colon

• Published in: The Journal of biological chemistry Vol. 273; no. 14; p. 7894
• Main Authors: Juan Codina, Juan T. Delmas-Mata, Thomas D. DuBose, Jr
• Format: Journal Article
• Language: English
• Published: American Society for Biochemistry and Molecular Biology 03.04.1998
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.14.7894

Previous experiments from our laboratory (Codina, J., Kone, B. C., Delmas-Mata, J. T., and DuBose, T. D., Jr. (1996) J. Biol. Chem . 271, 29759–29763) demonstrated that the α-subunit of the colonic H + ,K + -ATPase (HKα 2 ) requires coexpression with a β-subunit to support H + /K + transport in a heterologous expression system ( Xenopus laevis oocytes). In these studies, HKα 2 formed stable and functional α·β complexes when coexpressed with either the rat β 1 -subunit of the Na + ,K + -ATPase or the β-subunit of the gastric H + ,K + -ATPase, suggesting that different β-subunits may interact with HKα 2 . The present studies tested this hypothesis by development and application of a specific antibody against HKα 2 peptide. Subsequently, immunoprecipitation experiments were performed to determine if HKα 2 co-precipitates with the same β-subunit in organs known to express HKα 2 protein. The data demonstrate that HKα 2 assembles with β 1 -Na + ,K + -ATPase in the renal medulla and in distal colon.