Phorbol-ester is bound specifically to renal luminal membranes and stimulates the Na-H antiporter
Talor, Z.; Mejicano, G.C.
Research Communications in Chemical Pathology and Pharmacology 61(3): 335-343
1988
ISSN/ISBN: 0034-5164 PMID: 2847263 Document Number: 314632
We characterized binding of [3H]-phorbol-12,13-dibutyrate (an activator of protein kinase C) to highly purified rabbit cortical renal luminal membranes and measured its effect on the kinetics of the Na-H antiporter. There was 95% specific binding to luminal membranes and this binding was time, temperature and pH dependent with optimal binding at 4 degrees C and pH 7.4. Scatchard analysis of the binding revealed Kd of 0.8 microM and Bmax of 19.4 pmoles/mg protein. Phorbol-12,13-dibutyrate stimulated the Vmax of the Na-H antiporter by 16.5% +/- 4.7 at 10(-6) M and by 19.9% +/- 5.4 at 10(-5) M. The protein kinase C inhibitor H7(1) prevented the observed stimulation. Thus, there is a correlation between phorbol ester binding and phorbol ester stimulation of the Na-H antiporter. These data demonstrate that protein kinase C plays a role in the stimulation of the Na-H antiporter in renal luminal membranes.