The vacuolar-type H-ATPase in ovine rumen epithelium is regulated by metabolic signals.
In this study, the effect of metabolic inhibition (MI) by glucose substitution with 2-deoxyglucose (2-DOG) and/or application of antimycin A on ovine rumen epithelial cells (REC) vacuolar-type H(+)-ATPase (vH(+)-ATPase) activity was investigated. Using fluorescent spectroscopy, basal pH(i) of REC was measured to be 7.3 +/- 0.1 in HCO(3) (-)-free, glucose-containing NaCl medium. MI induced a strong pH(i) reduction (-0.44 +/- 0.04 pH units) with a more pronounced effect of 2-DOG compared to antimycin A (-0.30 +/- 0.03 versus -0.21 +/- 0.03 pH units). Treatment with foliomycin, a specific vH(+)-ATPase inhibitor, decreased REC pH(i) by 0.21 +/- 0.05 pH units. After MI induction, this effect was nearly abolished (-0.03 +/- 0.02 pH units). In addition, membrane-associated localization of vH(+)-ATPase B subunit disappeared. Metabolic control of vH(+)-ATPase involving regulation of its assembly state by elements of the glycolytic pathway could provide a means to adapt REC ATP consumption according to energy availability.
Kuzinski
Judith
J
Research Unit Nutritional Physiology Oskar Kellner, Research Institute for the Biology of Farm Animals (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
Zitnan
Rudolf
R
Warnke-Gurgel
Christina
C
Schweigel
Monika
M
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D015153:Blotting, Western; D001826:Body Fluids / Q000187:drug effects / Q000378:metabolism; D003847:Deoxyglucose / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000201:enzymology; D004848:Epithelium / Q000187:drug effects / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D012417:Rumen / Q000187:drug effects / Q000201:enzymology*; D012756:Sheep; D015398:Signal Transduction / Q000187:drug effects; D025262:Vacuolar Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*
D000968:Antimycin A; D000584:Amiloride; D003847:Deoxyglucose; D025262:Vacuolar Proton-Translocating ATPases