Observatorio de I+D+i UPM

Memorias de investigación
Research Publications in journals:
Luminal and cytosolic pH feedback on proton pump activity and ATP affinity of the V-type ATPase from Arabidopsis.
Year:2012
Research Areas
  • Plants and animal biology and ecology
Information
Abstract
Proton pumping of the vacuolar-type H(+)-ATPase into the lumen of the central plant organelle generates a proton gradient of often 1-2 pH units or more. Although structural aspects of the V-type ATPase have been studied in great detail, the question of whether and how the proton pump action is controlled by the proton concentration on both sides of the membrane is not understood. Applying the patch clamp technique to isolated vacuoles from Arabidopsis mesophyll cells in the whole-vacuole mode, we studied the response of the V-ATPase to protons, voltage, and ATP. Current-voltage relationships at different luminal pH values indicated decreasing coupling ratios with acidification. A detailed study of ATP-dependent H(+)-pump currents at a variety of different pH conditions showed a complex regulation of V-ATPase activity by both cytosolic and vacuolar pH. At cytosolic pH 7.5, vacuolar pH changes had relative little effects. Yet, at cytosolic pH 5.5, a 100-fold increase in vacuolar proton concentration resulted in a 70-fold increase of the affinity for ATP binding on the cytosolic side. Changes in pH on either side of the membrane seem to be transferred by the V-ATPase to the other side. A mathematical model was developed that indicates a feedback of proton concentration on peak H(+) current amplitude (v(max)) and ATP consumption (K(m)) of the V-ATPase. It proposes that for efficient V-ATPase function dissociation of transported protons from the pump protein might become higher with increasing pH. This feature results in an optimization of H(+) pumping by the V-ATPase according to existing H(+) concentrations.
International
Si
JCR
Si
Title
Journal of Biological Chemistry
ISBN
0021-9258
Impact factor JCR
5,328
Impact info
Datos JCR del ańo 2010
Volume
287
Journal number
From page
8986
To page
8993
Month
MARZO
Ranking
66/290 BIOCHEMISTRY & MOLECULAR BIOLOGY (SCI)
Participants
  • Autor: Florian Rienmüller (Universität Würzburg, Germany)
  • Autor: Ingo Dreyer . (UPM)
  • Autor: Gerald Schönknecht (Oklahoma State University, Stillwater, USA)
  • Autor: Alexander Schulz (Universität Würzburg, Germany)
  • Autor: Karin Schumacher (Universität Heidelberg, Germany)
  • Autor: Réka Nagy (Universität Zürich, Switzerland)
  • Autor: Enrico Martinoia (Universität Zürich, Switzerland)
  • Autor: Irene Marten (Universität Würzburg, Germany)
  • Autor: Rainer Hedrich (Universität Würzburg, Germany)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Redes Reguladoras del Desarrollo y Respuesta a Estrés en Plantas
  • Departamento: Biotecnología
S2i 2020 Observatorio de investigación @ UPM con la colaboración del Consejo Social UPM
Cofinanciación del MINECO en el marco del Programa INNCIDE 2011 (OTR-2011-0236)
Cofinanciación del MINECO en el marco del Programa INNPACTO (IPT-020000-2010-22)