title: Job Sharing in the Endomembrane System: Vacuolar Acidification Requires the Combined Activity of V-ATPase and V-PPase.
abstract: The presence of a large central vacuole is one of the hallmarks of a prototypical plant cell, and the multiple functions of this compartment require massive fluxes of molecules across its limiting membrane, the tonoplast. Transport is assumed to be energized by the membrane potential and the proton gradient established by the combined activity of two proton pumps, the vacuolar H(+)-pyrophosphatase (V-PPase) and the vacuolar H(+)-ATPase (V-ATPase). Exactly how labor is divided between these two enzymes has remained elusive. Here, we provide evidence using gain- and loss-of-function approaches that lack of the V-ATPase cannot be compensated for by increased V-PPase activity. Moreover, we show that increased V-ATPase activity during cold acclimation requires the presence of the V-PPase. Most importantly, we demonstrate that a mutant lacking both of these proton pumps is conditionally viable and retains significant vacuolar acidification, pointing to a so far undetected contribution of the trans-Golgi network/early endosome-localized V-ATPase to vacuolar pH.
authors.affiliation: Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Kriegel
authors.affiliation: Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Zaida
authors.initials: Z
authors.lastname: Andrés
authors.affiliation: Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Medzihradszky
authors.affiliation: Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Falco
authors.initials: F
authors.lastname: Krüger
authors.affiliation: Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Scholl
authors.affiliation: Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Delang
authors.affiliation: Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: M Görkem
authors.initials: MG
authors.lastname: Patir-Nebioglu
authors.affiliation: Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20742.
authors.forename: Gezahegn
authors.initials: G
authors.lastname: Gute
authors.affiliation: Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Haibing
authors.identifier: http://orcid.org/0000-0002-5418-6248
authors.initials: H
authors.lastname: Yang
authors.affiliation: Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20742.
authors.forename: Angus S
authors.identifier: http://orcid.org/0000-0001-5649-7413
authors.initials: AS
authors.lastname: Murphy
authors.affiliation: Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20742 Environmental Science and Technology, University of Maryland, College Park, Maryland 20742.
authors.forename: Wendy Ann
authors.identifier: http://orcid.org/0000-0003-0046-7324
authors.initials: WA
authors.lastname: Peer
authors.affiliation: Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Pfeiffer
authors.affiliation: Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Krebs
authors.affiliation: Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Jan U
authors.initials: JU
authors.lastname: Lohmann
authors.affiliation: Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany karin.schumacher@cos.uni-heidelberg.de.
authors.forename: Karin
authors.identifier: http://orcid.org/0000-0001-6484-8105
authors.initials: K
authors.lastname: Schumacher
mesh_terms: D000064:Acclimatization; D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D011992:Endosomes / Q000201:enzymology; D035264:Flowers / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D018745:Genome, Plant / Q000235:genetics*; D006863:Hydrogen-Ion Concentration; D043564:Inorganic Pyrophosphatase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018519:Meristem / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D016254:Mutagenesis, Insertional; D010641:Phenotype; D018517:Plant Roots / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D036226:Seedlings / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D017422:Sequence Analysis, DNA; D025262:Vacuolar Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014617:Vacuoles / Q000201:enzymology*; D021601:trans-Golgi Network / Q000201:enzymology
chemical_list: D029681:Arabidopsis Proteins; D025262:Vacuolar Proton-Translocating ATPases; C505048:AVP1 protein, Arabidopsis; D043564:Inorganic Pyrophosphatase