Stimulation of Na+/K+ ATPase activity and Na+ coupled glucose transport by β-catenin.

Autor: Sopjani M; Department of Physiology, University of Tübingen, Germany., Alesutan I, Wilmes J, Dërmaku-Sopjani M, Lam RS, Koutsouki E, Jakupi M, Föller M, Lang F
Jazyk: angličtina
Zdroj: Biochemical and biophysical research communications [Biochem Biophys Res Commun] 2010 Nov 19; Vol. 402 (3), pp. 467-70. Date of Electronic Publication: 2010 Oct 14.
DOI: 10.1016/j.bbrc.2010.10.049
Abstrakt: β-Catenin is a multifunctional protein stimulating as oncogenic transcription factor several genes important for cell proliferation. β-Catenin-regulated genes include the serum- and glucocorticoid-inducible kinase SGK1, which is known to stimulate a variety of transport systems. The present study explored the possibility that β-catenin influences membrane transport. To this end, β-catenin was expressed in Xenopus oocytes with or without SGLT1 and electrogenic transport determined by dual electrode voltage clamp. As a result, expression of β-catenin significantly enhanced the ouabain-sensitive current of the endogeneous Na(+)/K(+)-ATPase. Inhibition of vesicle trafficking by brefeldin A revealed that the stimulatory effect of β-catenin on the endogenous Na(+)/K(+)-ATPase was not due to enhanced stability of the pump protein in the cell membrane. Expression of β-catenin further enhanced glucose-induced current (Ig) in SGLT1-expressing oocytes. In the absence of SGLT1 Ig was negligible irrespective of β-catenin expression. The stimulating effect of β-catenin on both Na(+)/K(+) ATPase and SGLT1 activity was observed even in the presence of actinomycin D, an inhibitor of transcription. The experiments disclose a completely novel function of β-catenin, i.e. the regulation of transport.
(Copyright © 2010 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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