title: The cellular energization state affects peripheral stalk stability of plant vacuolar H+-ATPase and impairs vacuolar acidification.
abstract: The plant vacuolar H(+)-ATPase takes part in acidifying compartments of the endomembrane system including the secretory pathway and the vacuoles. The structural variability of the V-ATPase complex as well as its presence in different compartments and tissues involves multiple isoforms of V-ATPase subunits. Furthermore, a versatile regulation is essential to allow for organelle- and tissue-specific fine tuning. In this study, results from V-ATPase complex disassembly with a chaotropic reagent, immunodetection and in vivo fluorescence resonance energy transfer (FRET) analyses point to a regulatory mechanism in plants, which depends on energization and involves the stability of the peripheral stalks as well. Lowering of cellular ATP by feeding 2-deoxyglucose resulted in structural alterations within the V-ATPase, as monitored by changes in FRET efficiency between subunits VHA-E and VHA-C. Potassium iodide-mediated disassembly revealed a reduced stability of V-ATPase after 2-deoxyglucose treatment of the cells, but neither the complete V(1)-sector nor VHA-C was released from the membrane in response to 2-deoxyglucose treatment, precluding a reversible dissociation mechanism like in yeast. These data suggest the existence of a regulatory mechanism of plant V-ATPase by modification of the peripheral stator structure that is linked to the cellular energization state. This mechanism is distinct from reversible dissociation as reported for the yeast V-ATPase, but might represent an evolutionary precursor of reversible dissociation.
authors.affiliation: Department of Biochemistry and Physiology of Plants, Faculty of Biology-W5, Bielefeld University, D-33501 Bielefeld, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Schnitzer
authors.forename: Thorsten
authors.initials: T
authors.lastname: Seidel
authors.forename: Tim
authors.initials: T
authors.lastname: Sander
authors.forename: Dortje
authors.initials: D
authors.lastname: Golldack
authors.forename: Karl-Josef
authors.initials: KJ
authors.lastname: Dietz
mesh_terms: D000143:Acids / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D003847:Deoxyglucose / Q000494:pharmacology; D004734:Energy Metabolism / Q000187:drug effects; D004795:Enzyme Stability / Q000187:drug effects; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D058503:Mesophyll Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D025941:Protein Interaction Mapping; D055503:Protein Multimerization / Q000187:drug effects; D021122:Protein Subunits / Q000378:metabolism; D011523:Protoplasts / Q000187:drug effects / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism*; D014617:Vacuoles / Q000187:drug effects / Q000201:enzymology*
chemical_list: D000143:Acids; D007527:Isoenzymes; D021122:Protein Subunits; D000255:Adenosine Triphosphate; D003847:Deoxyglucose; D025262:Vacuolar Proton-Translocating ATPases