Publication Date:
2016-03-26
Description:
In eukaryotes, P-type adenosine triphosphatases (ATPases) generate the plasma membrane potential and drive secondary transport systems; however, despite their importance, their regulation remains poorly understood. We monitored at the single-molecule level the activity of the prototypic proton-pumping P-type ATPase Arabidopsis thaliana isoform 2 (AHA2). Our measurements, combined with a physical nonequilibrium model of vesicle acidification, revealed that pumping is stochastically interrupted by long-lived (~100 seconds) inactive or leaky states. Allosteric regulation by pH gradients modulated the switch between these states but not the pumping or leakage rates. The autoinhibitory regulatory domain of AHA2 reduced the intrinsic pumping rates but increased the dwell time in the active pumping state. We anticipate that similar functional dynamics underlie the operation and regulation of many other active transporters.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Veshaguri, Salome -- Christensen, Sune M -- Kemmer, Gerdi C -- Ghale, Garima -- Moller, Mads P -- Lohr, Christina -- Christensen, Andreas L -- Justesen, Bo H -- Jorgensen, Ida L -- Schiller, Jurgen -- Hatzakis, Nikos S -- Grabe, Michael -- Pomorski, Thomas Gunther -- Stamou, Dimitrios -- R21-GM100224/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2016 Mar 25;351(6280):1469-73. doi: 10.1126/science.aad6429.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Bionanotecnology and Nanomedicine Laboratory, University of Copenhagen, Copenhagen, Denmark. Department of Chemistry, University of Copenhagen, Copenhagen, Denmark. Nano-Science Center, University of Copenhagen, Copenhagen, Denmark. Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark. ; Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg Denmark. ; Institute of Medical Physics and Biophysics, Faculty of Medicine, University of Leipzig, Leipzig, Germany. ; Cardiovascular Research Institute, Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27013734" target="_blank"〉PubMed〈/a〉
Keywords:
Allosteric Regulation
;
Arabidopsis Proteins/antagonists & inhibitors/chemistry/*metabolism
;
Hydrogen-Ion Concentration
;
Ion Transport
;
Membrane Potentials/drug effects/physiology
;
Molecular Imaging
;
Protein Structure, Tertiary
;
Proton-Translocating ATPases/antagonists & inhibitors/chemistry/*metabolism
;
*Protons
;
Valinomycin/pharmacology
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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