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Seidel T. The Plant V-ATPase. FRONTIERS IN PLANT SCIENCE 2022; 13:931777. [PMID: 35845650 PMCID: PMC9280200 DOI: 10.3389/fpls.2022.931777] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/03/2022] [Indexed: 05/25/2023]
Abstract
V-ATPase is the dominant proton pump in plant cells. It contributes to cytosolic pH homeostasis and energizes transport processes across endomembranes of the secretory pathway. Its localization in the trans Golgi network/early endosomes is essential for vesicle transport, for instance for the delivery of cell wall components. Furthermore, it is crucial for response to abiotic and biotic stresses. The V-ATPase's rather complex structure and multiple subunit isoforms enable high structural flexibility with respect to requirements for different organs, developmental stages, and organelles. This complexity further demands a sophisticated assembly machinery and transport routes in cells, a process that is still not fully understood. Regulation of V-ATPase is a target of phosphorylation and redox-modifications but also involves interactions with regulatory proteins like 14-3-3 proteins and the lipid environment. Regulation by reversible assembly, as reported for yeast and the mammalian enzyme, has not be proven in plants but seems to be absent in autotrophic cells. Addressing the regulation of V-ATPase is a promising approach to adjust its activity for improved stress resistance or higher crop yield.
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2
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Kabała K, Janicka-Russak M, Reda M, Migocka M. Transcriptional regulation of the V-ATPase subunit c and V-PPase isoforms in Cucumis sativus under heavy metal stress. PHYSIOLOGIA PLANTARUM 2014; 150:32-45. [PMID: 23718549 DOI: 10.1111/ppl.12064] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 04/11/2013] [Indexed: 05/11/2023]
Abstract
Two electrogenic proton pumps, vacuolar H(+) transporting ATPase (V-ATPase, EC 3.6.3.14) and vacuolar H(+) transporting inorganic pyrophosphatase (V-PPase, EC 3.6.1.1), co-exist in the vacuolar membrane of plant cells. In this work, all CsVHA and CsVHP genes encoding V-ATPase and V-PPase, respectively, were identified in the cucumber genome. Among them, three CsVHA-c genes for V-ATPase subunit c and two CsVHP1 genes for type I V-PPase were analyzed in detail. Individual isogenes were differentially regulated in plant tissues and during plant development as well as under changing environmental conditions. CsVHA-c1 and CsVHA-c2 showed similar tissue-specific expression patterns with the highest levels in stamens and old leaves. CsVHP1;1 was predominantly expressed in roots and female flowers. In contrast, both CsVHA-c3 and CsVHP1;2 remained in a rather constant ratio in all examined cucumber organs. Under heavy metal stress, the transcript amount of CsVHA-c1 and CsVHP1;1 showed a pronounced stress-dependent increase after copper and nickel treatment. CsVHA-c3 was upregulated by nickel only whereas CsVHA-c2 was induced by all metals with the most visible effect of copper. Additionally, CsVHP1;2 showed a tendency to be upregulated by copper and zinc. We propose that CsVHA-c1, CsVHA-c2 and CsVHP1;1 are essential elements of mechanisms involved in adaptation of cucumber plants to copper toxicity.
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Affiliation(s)
- Katarzyna Kabała
- Department of Plant Molecular Physiology, Institute of Experimental Biology, University of Wrocław, 50-328 , Wrocław, Poland
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3
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Hanitzsch M, Schnitzer D, Seidel T, Golldack D, Dietz KJ. Transcript level regulation of the vacuolar H+-ATPase subunit isoforms VHA-a, VHA-E and VHA-G inArabidopsis thaliana. Mol Membr Biol 2009; 24:507-18. [PMID: 17710654 DOI: 10.1080/09687680701447393] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The presence of isogenes encoding V-ATPase subunits seems to be a characteristic for plants. Twenty-eight genes encode for the 13 different subunits in Arabidopsis thaliana, 23 genes each are known in tomato (Solanum lycopersicum) and can be identified in rice (Oryza sativa), respectively. In Arabidopsis the four subunits VHA-B, -E, -G and -a are encoded by three isogenes each. The transcript levels of these subunits were analysed by in silico evaluation of transcript pattern derived from the NASC-array database and exemplarily confirmed by semiquantitative RT-PCR. A tissue specifity was observed for the isoforms of VHA-E and VHA-G, whereas expression of VHA-a isoforms appeared independent of the tissue. Inflicting environmental stresses upon plants resulted in differentiated expression patterns of VHA-isoforms. Whereas salinity had minor effect on the expression of V-ATPase genes in A. thaliana, heat and drought stress led to alterations in transcript amount and preference of isoforms. Correlation analysis identified two clusters of isoforms, which were co-regulated on the transcript level.
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Affiliation(s)
- Miriam Hanitzsch
- Plant Biochemistry and Physiology, Faculty of Biology-W5, Bielefeld University, Bielefeld, Germany
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Dettmer J, Liu TY, Schumacher K. Functional analysis of Arabidopsis V-ATPase subunit VHA-E isoforms. Eur J Cell Biol 2009; 89:152-6. [PMID: 19945769 DOI: 10.1016/j.ejcb.2009.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acidification of endomembrane compartments by the vacuolar H(+)-ATPase (V-ATPase) is an important mechanism to generate microenvironments suitable for various cellular functions. Differential assembly of subunit isoforms provides the potential to flexibly adapt the proton-pumping V-ATPase complex to changing physiological conditions and cell type-specific requirements. In Arabidopsis, the regulatory V-ATPase subunit E (VHA-E) is encoded by three genes with distinct expression patterns. We show here that VHA-E2, which belongs to a clade of pollen-specific VHA-E isoforms present in all higher plants, has a specialized but non-essential function during gametophyte development. Similarly, loss of the epidermis-specific isoform VHA-E3, which we show here to be transcriptionally regulated by the phytohormone jasmonic acid, does not cause obvious phenotypic changes. Furthermore, when expressed ubiquitously, VHA-E3, in contrast to VHA-E2, is able to complement loss of the essential subunit VHA-E1 indicating different degrees of functional specialization among the Arabidopsis VHA-E isoforms.
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Affiliation(s)
- Jan Dettmer
- ZMBP - Plant Physiology, Universität Tübingen, Auf der Morgenstelle 1, 72076 Tübingen, Germany
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Cloning and sequencing of V-ATPase subunit d from mung bean and its function in passive proton transport. J Bioenerg Biomembr 2009; 40:569-76. [PMID: 19194790 DOI: 10.1007/s10863-008-9193-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Accepted: 12/15/2008] [Indexed: 10/21/2022]
Abstract
We have previously shown that vacuolar H+-ATPase subcomplex V(o) from mung bean contains subunit d, however, its sequence and function were unknown. In the present study, we report the cloning and recombinant over expression of subunit d from mung bean in E. coli. To study the function of subunit d, two vacuolar H+-ATPase subcomplexes V(o) from mung bean were purified-one containing subunits a and c(c',c") and the other containing subunits a, c(c',c") and d. After reconstitution of the purified V(o) subcomplexes into liposomes, the proton translocation was studied. Our results show that the V(o) subcomplex in the absence of subunit d is a passive proton channel, while the V(o) subcomplex in the presence of the subunit d is not. Taken together, our data supports the conclusion that the subunit d of the plant vacuolar H(+)-ATPase from mung bean is positioned at the central stalk and involved in the proton translocation across the tonoplast membrane.
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Minami A, Fujiwara M, Furuto A, Fukao Y, Yamashita T, Kamo M, Kawamura Y, Uemura M. Alterations in detergent-resistant plasma membrane microdomains in Arabidopsis thaliana during cold acclimation. PLANT & CELL PHYSIOLOGY 2009; 50:341-59. [PMID: 19106119 DOI: 10.1093/pcp/pcn202] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Microdomains in the plasma membrane (PM) have been proposed to be involved in many important cellular events in plant cells. To understand the role of PM microdomains in plant cold acclimation, we isolated the microdomains as detergent-resistant plasma membrane fractions (DRMs) from Arabidopsis seedlings and compared lipid and protein compositions before and after cold acclimation. The DRM was enriched in sterols and glucocerebrosides, and the proportion of free sterols in the DRM increased after cold acclimation. The protein-to-lipid ratio in the DRM was greater than that in the total PM fraction. The protein amount recovered in DRMs decreased gradually during cold acclimation. Cold acclimation further resulted in quantitative changes in DRM protein profiles. Subsequent mass spectrometry and Western blot analyses revealed that P-type H(+)-ATPases, aquaporins and endocytosis-related proteins increased and, conversely, tubulins, actins and V-type H(+)-ATPase subunits decreased in DRMs during cold acclimation. Functional categorization of cold-responsive proteins in DRMs suggests that plant PM microdomains function as platforms of membrane transport, membrane trafficking and cytoskeleton interaction. These comprehensive changes in microdomains may be associated with cold acclimation of Arabidopsis.
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Meléndez-Hernández MG, Barrios MLL, Orozco E, Luna-Arias JP. The vacuolar ATPase from Entamoeba histolytica: molecular cloning of the gene encoding for the B subunit and subcellular localization of the protein. BMC Microbiol 2008; 8:235. [PMID: 19108705 PMCID: PMC2629482 DOI: 10.1186/1471-2180-8-235] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 12/23/2008] [Indexed: 11/10/2022] Open
Abstract
Background Entamoeba histolytica is a professional phagocytic cell where the vacuolar ATPase plays a key role. This enzyme is a multisubunit complex that regulates pH in many subcellular compartments, even in those that are not measurably acidic. It participates in a wide variety of cellular processes such as endocytosis, intracellular transport and membrane fusion. The presence of a vacuolar type H+-ATPase in E. histolytica trophozoites has been inferred previously from inhibition assays of its activity, the isolation of the Ehvma1 and Ehvma3 genes, and by proteomic analysis of purified phagosomes. Results We report the isolation and characterization of the Ehvma2 gene, which encodes for the subunit B of the vacuolar ATPase. This polypeptide is a 55.3 kDa highly conserved protein with 34 to 80% identity to orthologous proteins from other species. Particularly, in silico studies showed that EhV-ATPase subunit B displays 78% identity and 90% similarity to its Dictyostelium ortholog. A 462 bp DNA fragment of the Ehvma2 gene was expressed in bacteria and recombinant polypeptide was used to raise mouse polyclonal antibodies. EhV-ATPase subunit B antibodies detected a 55 kDa band in whole cell extracts and in an enriched fraction of DNA-containing organelles named EhkOs. The V-ATPase subunit B was located by immunofluorescence and confocal microscopy in many vesicles, in phagosomes, plasma membrane and in EhkOs. We also identified the genes encoding for the majority of the V-ATPase subunits in the E. histolytica genome, and proposed a putative model for this proton pump. Conclusion We have isolated the Ehvma2 gene which encodes for the V-ATPase subunit B from the E. histolytica clone A. This gene has a 154 bp intron and encodes for a highly conserved polypeptide. Specific antibodies localized EhV-ATPase subunit B in many vesicles, phagosomes, plasma membrane and in EhkOs. Most of the orthologous genes encoding for the EhV-ATPase subunits were found in the E. histolytica genome, indicating the conserved nature of V-ATPase in this parasite.
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Kawamura Y. Improved mathematical model for estimating H+ influx and H+ efflux in plant vacuolar vesicles acidified by ATPase or pyrophosphatase. Anal Biochem 2007; 369:137-48. [PMID: 17719554 DOI: 10.1016/j.ab.2007.06.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2007] [Revised: 05/28/2007] [Accepted: 06/20/2007] [Indexed: 11/30/2022]
Abstract
To adapt to environmental changes, plant cells very likely possess a biochemical system, using vacuoles, for maintaining cytoplasmic pH homeostasis. A simple approach is to estimate the active H(+) influx and H(+) efflux of isolated vacuolar vesicles, although there is no good mathematical model to describe H(+) flux. To establish a new quantitative model, vacuolar vesicles were isolated from hypocotyls of mung bean (Vigna radiata L.), and pyrophosphate (PPi)- or ATP-dependent acidification was monitored using acridine orange. The change of pH inside the vesicles (pH(in)) was calculated using a pH calibration curve relating fluorescence quenching with DeltapH. After formation of a steady state DeltapH, passive H(+) efflux was monitored after terminating pumping with ethylenediaminetetraacetate, and the relative H(+) permeability coefficient (p(H+)) was calculated. The H(+) efflux simulated using the p(H+) corresponded to the H(+) efflux determined experimentally. H(+) influx was then calculated by subtracting the predicted H(+) efflux from the experimental net H(+) influx. H(+) influx into vesicles driven by H(+)-PPase or H(+)-ATPase decreased exponentially as the intravesicular pH(in) decreased, suggesting modulation of pumping by DeltapH, pH(in), or both. Finally, the PPi- or ATP-dependent H(+) accumulation determined experimentally was closely simulated by the predicted H(+) influx and H(+) efflux. The ability to predict H(+) flux under different conditions provides a powerful tool for studying pH homeostasis.
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Affiliation(s)
- Yukio Kawamura
- Department of Cell Biology & Molecular Genetics, University of Maryland, HJ Patterson Hall, College Park, MD 20742-5815, USA.
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Schumacher K. Endomembrane proton pumps: connecting membrane and vesicle transport. CURRENT OPINION IN PLANT BIOLOGY 2006; 9:595-600. [PMID: 17008121 DOI: 10.1016/j.pbi.2006.09.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Accepted: 09/15/2006] [Indexed: 05/12/2023]
Abstract
pH-homeostasis in the endomembrane system requires the activity of proton-pumps. In animals, the progressive acidification of compartments along the endocytic and secretory pathways is critical for protein sorting and vesicle trafficking, and is achieved by the activity of the vacuolar H(+)-ATPase (V-ATPase). Plants have an additional endomembrane pump, the vacuolar H(+)-pyrophosphatase (V-PPase), and previous research was largely focused on the respective functions of the two pumps in secondary active transport across the tonoplast. Recent approaches, including reverse genetics, have not only provided evidence that both enzymes play unique and essential roles but have also highlighted the important functions of the two proton pumps in endocytic and secretory trafficking.
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Affiliation(s)
- Karin Schumacher
- ZMBP-Plant Physiology, Universität Tübingen, Auf der Morgenstelle 1, 72076 Tübingen, Germany.
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Bageshwar UK, Taneja-Bageshwar S, Moharram HM, Binzel ML. Two isoforms of the A subunit of the vacuolar H(+)-ATPase in Lycopersicon esculentum: highly similar proteins but divergent patterns of tissue localization. PLANTA 2005; 220:632-643. [PMID: 15449061 DOI: 10.1007/s00425-004-1377-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2004] [Accepted: 08/07/2004] [Indexed: 05/24/2023]
Abstract
The plant vacuolar H(+)-translocating ATPase (V-ATPase, EC 3.6.1.34) generates a H+ electro-chemical gradient across the tonoplast membrane. We isolated two full-length cDNA clones (VHA-A1 and VHA-A2) from tomato (Lycopersicon esculentum Mill. cv. Large Cherry Red) coding for two isoforms of the V-ATPase catalytic subunit (V-ATPases A1 and A2). The cDNA clones encoding the two isoforms share 90% identity at the nucleotide level and 96% identity at the amino acid level. The 5'- and 3'-untranslated regions, however, are highly diverse. Both V-ATPase A1 and A2 isoforms encode polypeptides of 623 amino acids, with calculated molecular masses of 68,570 and 68,715, respectively. The expression of VHA-A1 and accumulation of V-ATPase A1 polypeptide were ubiquitous in all tissues examined. In response to salinity, the abundances of both transcript (VHA-A1) and protein (V-ATPase A1) of the A1 isoform in leaves were nearly doubled. In contrast to the A1 isoform, VHA-A2 transcript and V-ATPase A2 polypeptide were only detected in abundance in roots, and in minor quantities in mature fruit. In roots, accumulation of transcripts and polypeptides did not change in response to salinity for either isoform. Subcellular localization indicated that the highest levels of both V-ATPase A1 and A2 isoforms were in the tonoplast. However, significant quantities of both isoforms were detected in membranes associated with endoplasmic reticulum and/or Golgi. Immunoprecipitation of dissociated V1 domains using isoform-specific antibodies showed that V1 domains consist of either V-ATPase A1 or A2 catalytic subunit isoforms.
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Affiliation(s)
- Umesh K Bageshwar
- Institute of Plant Genomics and Biotechnology/Department of Horticulture, Texas A & M University, College Station, TX 77843, USA
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11
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Strompen G, Dettmer J, Stierhof YD, Schumacher K, Jürgens G, Mayer U. Arabidopsis vacuolar H-ATPase subunit E isoform 1 is required for Golgi organization and vacuole function in embryogenesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 41:125-132. [PMID: 15610355 DOI: 10.1111/j.1365-313x.2004.02283.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Vacuolar H(+)-ATPases play an important role in maintaining the pH of endomembrane compartments in eukaryotic cells. The functional relevance of this homeostasis for multicellular development has not been studied in plants. Here, we analyze the biological consequences resulting from the lack of subunit E isoform 1 (VHA-E1) encoded by the Arabidopsis TUFF gene. tuff mutant embryos are lethal, displaying variably enlarged cells with multiple nuclei, large vacuoles containing inclusions, abnormal organization of Golgi stacks, and cell wall defects. Rescue of embryo lethality by cell cycle-regulated expression of VHA-E1 results in abnormal seedlings with non-functional meristems and defective cell differentiation. VHA-E1 is the predominant isoform in embryogenesis whereas VHA-E3 is expressed mainly in the endosperm and surrounding maternal tissues during seed development, and VHA-E2 is pollen-specific. VHA-E1 protein accumulates at endomembrane compartments including vacuoles and endosomes, but appears absent from the plasma membrane. Our results suggest an essential role for VHA-E1 in maintaining a functional secretory system during somatic development but not in the haploid gametophytes.
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Affiliation(s)
- Georg Strompen
- ZMBP, Entwicklungsgenetik, Universität Tübingen, Auf der Morgenstelle 3, D-72076 Tübingen, Germany
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12
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Li Z, Zhang X. Electron-microscopic structure of the V-ATPase from mung bean. PLANTA 2004; 219:948-954. [PMID: 15185079 DOI: 10.1007/s00425-004-1298-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2003] [Accepted: 04/22/2004] [Indexed: 05/24/2023]
Abstract
The vacuolar H(+)-ATPase from mung bean (Vigna radiata L. cv. Wilczek) was purified to homogeneity. The purified complex contained all the reported subunits from mung bean, but also included a 40-kDa subunit, corresponding to the membrane-associated subunit d, which has not previously been observed. The structure of the V-ATPase from mung bean was studied by electron microscopy of negatively stained samples. An analysis of over 6,000 single-particle images obtained by electron microscopy of the purified complex revealed that the complex, similar to other V-ATPases, is organized into two major domains V1 and Vo with overall dimensions of 25 nm x 13.7 nm and a stalk region connecting the V1 and Vo domains. Several individual areas of protein density were observed in the stalk region, indicating its complexity. The projections clearly showed that the complex contained one central stalk and at least two peripheral stalks. Subcomplexes containing subunits A, B and E, dissociated from the tonoplast membrane by KI, were purified. The structure of the subcomplex was also studied by electron microscopy followed by single-molecule analysis of 13,000 projections. Our preliminary results reveal an area of high protein density at the bottom of the subcomplex immediately below the cavity formed by the A and B subunits, indicating the position of subunit E.
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Affiliation(s)
- Zhuo Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101 Beijing, China
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Sun-Wada GH, Wada Y, Futai M. Vacuolar H+ pumping ATPases in luminal acidic organelles and extracellular compartments: common rotational mechanism and diverse physiological roles. J Bioenerg Biomembr 2004; 35:347-58. [PMID: 14635780 DOI: 10.1023/a:1025780932403] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cytoplasmic organelles with an acidic luminal pH include vacuoles, coated vesicles, lysosomes, the Golgi apparatus, and synaptic vesicles. Acidic compartments are also known outside specialized cells such as osteoclasts. The unique acidic pH is formed by V-ATPase (Vacuolar type ATPase), other ion transporters, and the buffering action of proteins inside the organelles. V-ATPase hydrolyzes ATP and transports protons inside an organelle or extracellular compartment. We have summarized recent progress on mouse V-ATPases and their varying localizations together with their mechanism emphasizing similarities with F-type ATPases.
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Affiliation(s)
- Ge-Hong Sun-Wada
- Division of Biological Sciences and Nanoscience, and Nanotechnology Center, Japan Science and Technology Cooperation, Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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Padmanaban S, Lin X, Perera I, Kawamura Y, Sze H. Differential expression of vacuolar H+-ATPase subunit c genes in tissues active in membrane trafficking and their roles in plant growth as revealed by RNAi. PLANT PHYSIOLOGY 2004; 134:1514-26. [PMID: 15051861 PMCID: PMC419827 DOI: 10.1104/pp.103.034025] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2003] [Revised: 12/24/2003] [Accepted: 12/26/2003] [Indexed: 05/18/2023]
Abstract
Acidification of intracellular compartments by the vacuolar-type H(+)-ATPases (VHA) is known to energize ion and metabolite transport, though cellular processes influenced by this activity are poorly understood. At least 26 VHA genes encode 12 subunits of the V(1)V(o)-ATPase complex in Arabidopsis, and how the expression, assembly, and activity of the pump are integrated into signaling networks that govern growth and adaptation are largely unknown. The role of multiple VHA-c genes encoding the 16-kD subunit of the membrane V(o) sector was investigated. Expression of VHA-c1, monitored by promoter-driven beta-glucuronidase (GUS) activity was responsive to light or dark in an organ-specific manner. VHA-c1 expression in expanding cotyledons, hypocotyls of etiolated seedlings, and elongation zone of roots supported a role for V-ATPase in cell enlargement. Mutants reduced in VHA-c1 transcript using dsRNA-mediated interference showed reduction in root growth relative to wild-type seedlings. In contrast, VHA-c3 promoter::GUS expression was undetectable in most organs of seedlings, but strong in the root cap. Interestingly, dsRNA-mediated mutants of vha-c3 also showed reduced root length and decreased tolerance to moderate salt stress. The results suggest that V-ATPase functions in the root cap influenced root growth. Expression of VHA-c1 and VHA-c3 in tissues with active membrane flow, including root cap, vascular strands, and floral style would support a model for participation of the V(o) sector and V(1)V(o)-ATPase in membrane trafficking and fusion. Two VHA-c genes are thus differentially expressed to support growth in expanding cells and to supply increased demand for V-ATPase in cells with active exocytosis.
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Affiliation(s)
- Senthilkumar Padmanaban
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742, USA
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15
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Drobny M, Schnölzer M, Fiedler S, Lüttge U, Fischer-Schliebs E, Christian AL, Ratajczak R. Phenotypic subunit composition of the tobacco (Nicotiana tabacum L.) vacuolar-type H(+)-translocating ATPase. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1564:243-55. [PMID: 12101019 DOI: 10.1016/s0005-2736(02)00459-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The model plant tobacco (Nicotiana tabacum L.) was chosen for a survey of the subunit composition of the V-ATPase at the protein level. V-ATPase was purified from tobacco leaf cell tonoplasts by solubilization with the nonionic detergent Triton X-100 and immunoprecipitation. In the purified fraction 12 proteins were present. By matrix-assisted laser-desorption ionization mass spectrometry (MALDI-MS) and amino acid sequencing 11 of these polypeptides could be identified as subunits A, B, C, D, F, G, c, d and three different isoforms of subunit E. The polypeptide which could not be identified by MALDI analysis might represent subunit H. The data presented here, for the first time, enable an unequivocal identification of V-ATPase subunits after gel electrophoresis and open the possibility to assign changes in polypeptide composition to variations in respective V-ATPase subunits occurring as a response to environmental conditions or during plant development.
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Affiliation(s)
- Martina Drobny
- Darmstadt University of Technology, Institute of Botany, Schnittspahnstrasse 3-5, D-64287, Darmstadt, Germany
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16
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Sun-Wada GH, Imai-Senga Y, Yamamoto A, Murata Y, Hirata T, Wada Y, Futai M. A proton pump ATPase with testis-specific E1-subunit isoform required for acrosome acidification. J Biol Chem 2002; 277:18098-105. [PMID: 11872743 DOI: 10.1074/jbc.m111567200] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The vacuolar-type H(+)-ATPases (V-ATPases) are a family of multimeric proton pumps involved in a wide variety of physiological processes. We have identified two novel mouse genes, Atp6e1 and Atp6e2, encoding testis-specific (E1) and ubiquitous (E2) V-ATPase subunit E isoforms, respectively. The E1 transcript appears about 3 weeks after birth, corresponding to the start of meiosis, and is expressed specifically in round spermatids in seminiferous tubules. Immunohistochemistry with isoform-specific antibodies revealed that the V-ATPase with E1 and a2 isoforms is located specifically in developing acrosomes of spermatids and acrosomes in mature sperm. In contrast, the E2 isoform was expressed in all tissues examined and present in the perinuclear compartments of spermatocytes. The E1 isoform exhibits 70% identity with the E2, and both isoforms functionally complemented a null mutation of the yeast counterpart VMA4, indicating that they are bona fide V-ATPase subunits. The chimeric enzymes showed slightly lower K(m)(ATP) than yeast V-ATPase. Consistent with the temperature-sensitive growth of Deltavma4-expressing E1 isoform, vacuolar membrane vesicles exhibited temperature-sensitive coupling between ATP hydrolysis and proton transport. These results suggest that E1 isoform is essential for energy coupling involved in acidification of acrosome.
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Affiliation(s)
- Ge-Hong Sun-Wada
- Division of Biological Sciences, Institute of Scientific and Industrial Research, Osaka University, Core Research for Evolutional Science and Technology (CREST) of the Japan Science and Technology Corp., Osaka 567-0047, Japan
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Magnotta SM, Gogarten JP. Multi site polyadenylation and transcriptional response to stress of a vacuolar type H+-ATPase subunit A gene in Arabidopsis thaliana. BMC PLANT BIOLOGY 2002; 2:3. [PMID: 11985780 PMCID: PMC103671 DOI: 10.1186/1471-2229-2-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2002] [Accepted: 04/02/2002] [Indexed: 05/21/2023]
Abstract
BACKGROUND Vacuolar type H+-ATPases play a critical role in the maintenance of vacuolar homeostasis in plant cells. V-ATPases are also involved in plants' defense against environmental stress. This research examined the expression and regulation of the catalytic subunit of the vacuolar type H+-ATPase in Arabidopsis thaliana and the effect of environmental stress on multiple transcripts generated by this gene. RESULTS Evidence suggests that subunit A of the vacuolar type H+-ATPase is encoded by a single gene in Arabidopsis thaliana. Genome blot analysis showed no indication of a second subunit A gene being present. The single gene identified was shown by whole RNA blot analysis to be transcribed in all organs of the plant. Subunit A was shown by sequencing the 3' end of multiple cDNA clones to exhibit multi site polyadenylation. Four different poly (A) tail attachment sites were revealed. Experiments were performed to determine the response of transcript levels for subunit A to environmental stress. A PCR based strategy was devised to amplify the four different transcripts from the subunit A gene. CONCLUSIONS Amplification of cDNA generated from seedlings exposed to cold, salt stress, and etiolation showed that transcript levels for subunit A of the vacuolar type H+-ATPase in Arabidopsis were responsive to stress conditions. Cold and salt stress resulted in a 2-4 fold increase in all four subunit A transcripts evaluated. Etiolation resulted in a slight increase in transcript levels. All four transcripts appeared to behave identically with respect to stress conditions tested with no significant differential regulation.
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Affiliation(s)
- Scot M Magnotta
- Department of Biology, University of Hartford, West Hartford, CT, USA
| | - Johann Peter Gogarten
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
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Ikeda M, Hinohara M, Umami K, Taguro Y, Okada Y, Wada Y, Nakanishi Y, Maeshima M. Expression of V-ATPase proteolipid subunit of Acetabularia acetabulum in a VMA3-deficient strain of Saccharomyces cerevisiae and its complementation study. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:6097-104. [PMID: 11733003 DOI: 10.1046/j.0014-2956.2001.ejb.2556.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The function of the translation products of six different cDNAs for Acetabularia V-ATPase proteolipid subunit (AACEVAPD1 to AACEVAPD6) was examined using a Saccharomyces cerevisiae VMA3-deficient strain that lacked its own gene for one of the proteolipid subunits of V-ATPase. Expression of the cDNAs in the strain revealed that four cDNAs from the six complemented the proton transport activity into the vacuole, visualized by fluorescence microscopy. The vacuolar-membrane-enriched fractions from the four transformants showed cross-reactivity with antibodies against the subunits a and A of S. cerevisiae V-ATPase. Two translation products from the other two cDNAs were demonstrated not to be localized in vacuolar membranes, and thus could not complement the function of the VMA3-deficient strain. As the primary structures deduced from the former four cDNAs are similar but clearly different from those of the latter two, the latter two translation products may not be able to substitute for theVMA3 gene product.
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Affiliation(s)
- M Ikeda
- Department of Nutritional Science, Faculty of Health and Welfare Science, Okayama Prefectural University, Soja, Japan
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Dietz KJ, Tavakoli N, Kluge C, Mimura T, Sharma SS, Harris GC, Chardonnens AN, Golldack D. Significance of the V-type ATPase for the adaptation to stressful growth conditions and its regulation on the molecular and biochemical level. JOURNAL OF EXPERIMENTAL BOTANY 2001; 52:1969-80. [PMID: 11559732 DOI: 10.1093/jexbot/52.363.1969] [Citation(s) in RCA: 190] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Two electrogenic H(+)-pumps, the vacuolar type H(+)-ATPase (V-ATPase) and the vacuolar pyrophosphatase, coexist at membranes of the secretory pathway of plants. The V-ATPase is the dominant H(+)-pump at endomembranes of most plant cells, both in terms of protein amount and, frequently, also in activity. The V-ATPase is indispensable for plant growth under normal conditions due to its role in energizing secondary transport, maintenance of solute homeostasis and, possibly, in facilitating vesicle fusion. Under stress conditions such as salinity, drought, cold, acid stress, anoxia, and excess heavy metals in the soil, survival of the cells depends strongly on maintaining or adjusting the activity of the V-ATPase. Regulation of gene expression and activity are involved in adapting the V-ATPase on long- and short-term bases. The mechanisms known to regulate the V-ATPase are summarized in this paper with an emphasis on their implications for growth and development under stress.
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Affiliation(s)
- K J Dietz
- Department of Physiology and Biochemistry of Plants, Faculty of Biology, University of Bielefeld, D-33501 Bielefeld, Germany.
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Kawamura Y, Arakawa K, Maeshima M, Yoshida S. ATP analogue binding to the A subunit induces conformational changes in the E subunit that involves a disulfide bond formation in plant V-ATPase. ACTA ACUST UNITED AC 2001; 268:2801-9. [PMID: 11358495 DOI: 10.1046/j.1432-1327.2001.02139.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Vacuolar H+-ATPase (V-ATPase) consists of a catalytic head, a stalk part and a membrane domain. We indirectly investigated the interaction between the A subunit (catalytic head) and the E subunit (stalk part) using an ATP analogue, adenosine 5'-[beta,gamma-imino]triphosphate (AMP-PNP), which holds the enzyme in the substrate-binding state. AMP-PNP treatment caused a mobility shift of the E subunit with a faster migration in SDS/polyacrylamide gel electrophoresis without a reductant, while ATP treatment did not. A mobility shift of the E subunit has been detected in several plants. As polypeptides with intramolecular disulfide bonds migrate faster than those without disulfide bonds, the mobility shift may be due to the formation of an intramolecular disulfide bond by two cysteine residues conserved among several plant species. The mobility shift may be involved in the binding of AMP-PNP to the ATP-binding site, which exists in the A and B subunits, as it was inhibited by the addition of ATP. Pretreatment with 2'-3'-O-(4-benzoylbenzoyl)-ATP (Bz-ATP), which modifies the ATP-binding site of the B subunit under UV illumination, did not inhibit the mobility shift of the E subunit caused by AMP-PNP treatment. The response of V-ATPase following the AMP-PNP binding may cause a conformational change in the E subunit into a form that is susceptible to oxidation of cysteine residues. This is the first demonstration of interaction between the A and E subunits in the substrate-binding state of a plant V-ATPase.
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Affiliation(s)
- Y Kawamura
- Cryobiosystem Research Center, Iwate University, Iwate, Japan
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Maeshima M. TONOPLAST TRANSPORTERS: Organization and Function. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:469-497. [PMID: 11337406 DOI: 10.1146/annurev.arplant.52.1.469] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Regulation of the contents and volume of vacuoles in plant cells depends on the coordinated activities of transporters and channels located in the tonoplast (vacuolar membrane). The three major components of the tonoplast are two proton pumps, the vacuolar H+-ATPase (V-ATPase) and H+-pyrophosphatase (V-PPase), and aquaporins. The tertiary structure of the V-ATPase complex and properties of its subunits have been characterized by biochemical and genetic techniques. These studies and a comparison with the F-type ATPase have enabled estimation of the dynamics of V-ATPase activity during catalysis. V-PPase, a simple proton pump, has been identified and cloned from various plant species and other organisms, such as algae and phototrophic bacteria, and functional motifs of the enzyme have been determined. Aquaporin, serving as the water channel, is the most abundant protein in the tonoplast in most plants. A common molecular architecture of aquaporins in mammals and plants has been determined by two-dimensional crystallographic analysis. Furthermore, recent molecular biological studies have revealed several other types of tonoplast transporters, such as the Ca2+-ATPase, Ca2+/H+ antiporter and Na+/H+ antiporter. Many other transporters and channels in the tonoplast remain to be identified; their activities have already been detected. This review presents an overview of the field and discusses recent findings on the tonoplast protein components that have been identified and their physiological consequences.
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Affiliation(s)
- Masayoshi Maeshima
- Laboratory of Biochemistry, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan; e-mail:
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Golldack D, Dietz KJ. Salt-induced expression of the vacuolar H+-ATPase in the common ice plant is developmentally controlled and tissue specific. PLANT PHYSIOLOGY 2001; 125:1643-54. [PMID: 11299346 PMCID: PMC88822 DOI: 10.1104/pp.125.4.1643] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2000] [Revised: 09/14/2000] [Accepted: 11/20/2000] [Indexed: 05/18/2023]
Abstract
For salinity stress tolerance in plants, the vacuolar type H+-ATPase (V-ATPase) is of prime importance in energizing sodium sequestration into the central vacuole and it is known to respond to salt stress with increased expression and enzyme activity. In this work we provide information that the expressional response to salinity of the V-ATPase is regulated tissue and cell specifically under developmental control in the facultative halophyte common ice plant (Mesembryanthemum crystallinum). By transcript analysis of subunit E of the V-ATPase, amounts did not change in response to salinity stress in juvenile plants that are not salt-tolerant. In a converse manner, in halotolerant mature plants the transcript levels increased in leaves, but not in roots when salt stressed for 72 h. By in situ hybridizations and immunocytological protein analysis, subunit E was shown to be synthesized in all cell types. During salt stress, signal intensity declined in root cortex cells and in the cells of the root vascular cylinder. In salt-stressed leaves of mature plants, the strongest signals were localized surrounding the vasculature. Within control cells and with highest abundance in mesophyll cells of salt-treated leaves, accumulation of subunit E protein was observed in the cytoplasm, indicating its presence not only in the tonoplast, but also in other endoplasmic compartments.
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Affiliation(s)
- D Golldack
- Department of Physiology and Biochemistry of Plants, Faculty of Biology, University of Bielefeld, D-33501 Bielefeld, Germany
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Metzler DE, Metzler CM, Sauke DJ. Electron Transport, Oxidative Phosphorylation, and Hydroxylation. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50021-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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