TU Darmstadt / ULB / TUbiblio

Inhibition of the yeast V-type ATPase by cytosolic ADP.

Kettner, C. and Obermeyer, G. and Bertl, A. (2003):
Inhibition of the yeast V-type ATPase by cytosolic ADP.
In: FEBS letters, pp. 119-124, 535, (1-3), ISSN 0014-5793,
[Online-Edition: http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T3...],
[Article]

Abstract

The activity of the vacuolar H(+)-ATPase has been characterized in isolated vacuoles of the yeast Saccharomyces cerevisiae by means of the patch-clamp technique. With cytosolic calcium at virtually zero (<10(-9) M), Mg-ATP induced a transient, bafilomycin A(1)-sensitive current corresponding to the flow of positive charges from the cytoplasmic surface to the vacuolar lumen. The Mg-ATP-dependent current reached its maximum amplitude (30+/-8 mA m(-2) with 5 mM Mg-ATP, n=34) within 15-20 s and declined slowly over a period of about 15-20 min even in the continuous presence of Mg-ATP. This decline of pumping activity was independent of the cytosolic KCl concentration, suggesting an inhibitory mechanism different from the high salt-induced dissociation of V(0) and V(1) reported for the V-ATPase of plants and fungi. Cytosolic ADP was found to modulate the pump activity since Mg-ATP-induced pump current was smaller if monitored in the presence of 5 mM ADP and addition of 5 mM ADP in the presence of 5 mM Mg-ATP reduced the pump current by more than 50%. Furthermore, reduction of the cytosolic ADP concentration by the ATP-regenerating system creatine phosphate/creatine kinase partially relieved the endogenous inhibition of the V-ATPase, confirming that interaction of cytosolic ADP with the V-ATPase is the reason for the transient nature of the pump current in yeast vacuoles.

Item Type: Article
Erschienen: 2003
Creators: Kettner, C. and Obermeyer, G. and Bertl, A.
Title: Inhibition of the yeast V-type ATPase by cytosolic ADP.
Language: English
Abstract:

The activity of the vacuolar H(+)-ATPase has been characterized in isolated vacuoles of the yeast Saccharomyces cerevisiae by means of the patch-clamp technique. With cytosolic calcium at virtually zero (<10(-9) M), Mg-ATP induced a transient, bafilomycin A(1)-sensitive current corresponding to the flow of positive charges from the cytoplasmic surface to the vacuolar lumen. The Mg-ATP-dependent current reached its maximum amplitude (30+/-8 mA m(-2) with 5 mM Mg-ATP, n=34) within 15-20 s and declined slowly over a period of about 15-20 min even in the continuous presence of Mg-ATP. This decline of pumping activity was independent of the cytosolic KCl concentration, suggesting an inhibitory mechanism different from the high salt-induced dissociation of V(0) and V(1) reported for the V-ATPase of plants and fungi. Cytosolic ADP was found to modulate the pump activity since Mg-ATP-induced pump current was smaller if monitored in the presence of 5 mM ADP and addition of 5 mM ADP in the presence of 5 mM Mg-ATP reduced the pump current by more than 50%. Furthermore, reduction of the cytosolic ADP concentration by the ATP-regenerating system creatine phosphate/creatine kinase partially relieved the endogenous inhibition of the V-ATPase, confirming that interaction of cytosolic ADP with the V-ATPase is the reason for the transient nature of the pump current in yeast vacuoles.

Journal or Publication Title: FEBS letters
Volume: 535
Number: 1-3
Divisions: 10 Department of Biology
?? fb10_botanik ??
10 Department of Biology > Yeast Membrane Biology
Date Deposited: 29 Nov 2010 15:25
Official URL: http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T3...
Identification Number: doi:10.1016/S0014-5793(02)03886-3
Export:
Suche nach Titel in: TUfind oder in Google

Optionen (nur für Redakteure)

View Item View Item