The H,K-ATPase beta-subunit can act as a surrogate for the beta-subunit of Na,K-pumps

Na,K-ATPase and H,K-ATPase are the only members of the P-type ATPases in which a glycosylated beta-subunit is part of the purified active enzyme. In this study, we have followed the synthesis and the posttranslational processing of the beta-subunit of H,K-ATPase (beta HK) in Xenopus oocytes injected...

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Bibliographic Details
Published in:The Journal of biological chemistry 1991-10, Vol.266 (29), p.19131-19134
Main Authors: HORISBERGER, J.-D, JAUNIN, P, REUBEN, M. A, LASATER, L. S, CHOW, D. C, FORTE, J. G, SACHS, G, ROSSIER, B. C, GEERING, K
Format: Article
Language:English
Subjects:
Adenosine Triphosphatases - metabolism
Analytical, structural and metabolic biochemistry
Animals
beta subunit
Biological and medical sciences
Electrophoresis, Polyacrylamide Gel
Enzymes and enzyme inhibitors
Fundamental and applied biological sciences. Psychology
Glycosylation
H super(+)/K super(+)-transporting ATPase
H(+)-K(+)-Exchanging ATPase
Hexosaminidases - metabolism
Hydrolases
Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase
membrane proteins
Na super(+)/K super(+)-transporting ATPase
Ouabain - metabolism
Precipitin Tests
Protein Processing, Post-Translational
rabbits
RNA - metabolism
RNA, Complementary
Rubidium - metabolism
Sodium-Potassium-Exchanging ATPase - metabolism
utilization
Xenopus laevis
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Summary:Na,K-ATPase and H,K-ATPase are the only members of the P-type ATPases in which a glycosylated beta-subunit is part of the purified active enzyme. In this study, we have followed the synthesis and the posttranslational processing of the beta-subunit of H,K-ATPase (beta HK) in Xenopus oocytes injected with beta HK cRNA and have tested whether it can act as a surrogate for the beta-subunit of Na,K-ATPase (beta NaK) to support the functional expression of Na,K-pumps. In Xenopus oocytes, beta HK is processed from an Endo H-sensitive 51-kDa coreglycosylated form to an Endo H-resistant 71-kDa fully glycosylated form. Similar to beta NaK, beta HK can stabilize and increase the trypsin resistance of alpha-subunits of Na,K-ATPase (alpha NaK). Finally, expression of beta HK together with alpha NaK leads to an increased number of ouabain binding sites at the plasma membrane accompanied by an increased Rb+ uptake and Na,K-pump current. Our data suggest that beta HK, similar to beta NaK, can assemble to alpha NaK, support the structural maturation and the intracellular transport of catalytic alpha NaK, and ultimately form active alpha NaK-beta HK complexes with Na,K-pump transport properties.
ISSN:0021-9258
1083-351X
DOI:10.1016/s0021-9258(18)54968-1