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Toleco MR, Naake T, Zhang Y, Heazlewood JL, R. Fernie A. Plant Mitochondrial Carriers: Molecular Gatekeepers That Help to Regulate Plant Central Carbon Metabolism. PLANTS 2020; 9:plants9010117. [PMID: 31963509 PMCID: PMC7020223 DOI: 10.3390/plants9010117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/14/2020] [Accepted: 01/15/2020] [Indexed: 12/11/2022]
Abstract
The evolution of membrane-bound organelles among eukaryotes led to a highly compartmentalized metabolism. As a compartment of the central carbon metabolism, mitochondria must be connected to the cytosol by molecular gates that facilitate a myriad of cellular processes. Members of the mitochondrial carrier family function to mediate the transport of metabolites across the impermeable inner mitochondrial membrane and, thus, are potentially crucial for metabolic control and regulation. Here, we focus on members of this family that might impact intracellular central plant carbon metabolism. We summarize and review what is currently known about these transporters from in vitro transport assays and in planta physiological functions, whenever available. From the biochemical and molecular data, we hypothesize how these relevant transporters might play a role in the shuttling of organic acids in the various flux modes of the TCA cycle. Furthermore, we also review relevant mitochondrial carriers that may be vital in mitochondrial oxidative phosphorylation. Lastly, we survey novel experimental approaches that could possibly extend and/or complement the widely accepted proteoliposome reconstitution approach.
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Affiliation(s)
- M. Rey Toleco
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; (M.R.T.); (T.N.); (Y.Z.)
- School of BioSciences, the University of Melbourne, Victoria 3010, Australia;
| | - Thomas Naake
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; (M.R.T.); (T.N.); (Y.Z.)
| | - Youjun Zhang
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; (M.R.T.); (T.N.); (Y.Z.)
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | | | - Alisdair R. Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; (M.R.T.); (T.N.); (Y.Z.)
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
- Correspondence:
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Robles P, Micol JL, Quesada V. Arabidopsis MDA1, a nuclear-encoded protein, functions in chloroplast development and abiotic stress responses. PLoS One 2012; 7:e42924. [PMID: 22905186 PMCID: PMC3414458 DOI: 10.1371/journal.pone.0042924] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 07/13/2012] [Indexed: 11/17/2022] Open
Abstract
Most chloroplast and mitochondrial proteins are encoded by nuclear genes, whose functions remain largely unknown because mutant alleles are lacking. A reverse genetics screen for mutations affecting the mitochondrial transcription termination factor (mTERF) family in Arabidopsis thaliana allowed us to identify 75 lines carrying T-DNA insertions. Two of them were homozygous for insertions in the At4g14605 gene, which we dubbed MDA1 (MTERF DEFECTIVE IN Arabidopsis1). The mda1 mutants exhibited altered chloroplast morphology and plant growth, and reduced pigmentation of cotyledons, leaves, stems and sepals. The mda1 mutations enhanced salt and osmotic stress tolerance and altered sugar responses during seedling establishment, possibly as a result of reduced ABA sensitivity. Loss of MDA1 function caused up-regulation of the RpoTp/SCA3 nuclear gene encoding a plastid RNA polymerase and modified the steady-state levels of chloroplast gene transcripts. Double mutant analyses indicated that MDA1 and the previously described mTERF genes SOLDAT10 and RUG2 act in different pathways. Our findings reveal a new role for mTERF proteins in the response to abiotic stress, probably through perturbed ABA retrograde signalling resulting from a disruption in chloroplast homeostasis.
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Affiliation(s)
- Pedro Robles
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, Spain
| | - José Luis Micol
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, Spain
| | - Víctor Quesada
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, Spain
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Miura K, Sato A, Ohta M, Furukawa J. Increased tolerance to salt stress in the phosphate-accumulating Arabidopsis mutants siz1 and pho2. PLANTA 2011; 234:1191-9. [PMID: 21748325 DOI: 10.1007/s00425-011-1476-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 06/28/2011] [Indexed: 05/23/2023]
Abstract
High salinity is an environmental factor that inhibits plant growth and development, leading to large losses in crop yields. We report here that mutations in SIZ1 or PHO2, which cause more accumulation of phosphate compared with the wild type, enhance tolerance to salt stress. The siz1 and pho2 mutations reduce the uptake and accumulation of Na(+). These mutations are also able to suppress the Na(+) hypersensitivity of the sos3-1 mutant, and genetic analyses suggest that SIZ1 and SOS3 or PHO2 and SOS3 have an additive effect on the response to salt stress. Furthermore, the siz1 mutation cannot suppress the Li(+) hypersensitivity of the sos3-1 mutant. These results indicate that the phosphate-accumulating mutants siz1 and pho2 reduce the uptake and accumulation of Na(+), leading to enhanced salt tolerance, and that, genetically, SIZ1 and PHO2 are likely independent of SOS3-dependent salt signaling.
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Affiliation(s)
- Kenji Miura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8572, Japan.
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Bahaji A, Ovecka M, Bárány I, Risueño MC, Muñoz FJ, Baroja-Fernández E, Montero M, Li J, Hidalgo M, Sesma MT, Ezquer I, Testillano PS, Pozueta-Romero J. Dual targeting to mitochondria and plastids of AtBT1 and ZmBT1, two members of the mitochondrial carrier family. PLANT & CELL PHYSIOLOGY 2011; 52:597-609. [PMID: 21330298 DOI: 10.1093/pcp/pcr019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Zea mays and Arabidopsis thaliana Brittle 1 (ZmBT1 and AtBT1, respectively) are members of the mitochondrial carrier family. Although they are presumed to be exclusively localized in the envelope membranes of plastids, confocal fluorescence microscopy analyses of potato, Arabidopsis and maize plants stably expressing green fluorescent protein (GFP) fusions of ZmBT1 and AtBT1 revealed that the two proteins have dual localization to plastids and mitochondria. The patterns of GFP fluorescence distribution observed in plants stably expressing GFP fusions of ZmBT1 and AtBT1 N-terminal extensions were fully congruent with that of plants expressing a plastidial marker fused to GFP. Furthermore, the patterns of GFP fluorescence distribution and motility observed in plants expressing the mature proteins fused to GFP were identical to those observed in plants expressing a mitochondrial marker fused to GFP. Electron microscopic immunocytochemical analyses of maize endosperms using anti-ZmBT1 antibodies further confirmed that ZmBT1 occurs in both plastids and mitochondria. The overall data showed that (i) ZmBT1 and AtBT1 are dually targeted to mitochondria and plastids; (ii) AtBT1 and ZmBT1 N-terminal extensions comprise targeting sequences exclusively recognized by the plastidial compartment; and (iii) targeting sequences to mitochondria are localized within the mature part of the BT1 proteins.
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Affiliation(s)
- Abdellatif Bahaji
- Instituto de Agrobiotecnología, Universidad Pública de Navarra/Consejo Superior de Investigaciones Científicas/Gobierno de Navarra, Mutiloako Etorbidea Zenbaki Gabe, 31192 Mutiloabeti, Nafarroa, Spain
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Abstract
Due to the presence of plastids, eukaryotic photosynthetic cells represent the most highly compartmentalized eukaryotic cells. This high degree of compartmentation requires the transport of solutes across intracellular membrane systems by specific membrane transporters. In this review, we summarize the recent progress on functionally characterized intracellular plant membrane transporters and we link transporter functions to Arabidopsis gene identifiers and to the transporter classification system. In addition, we outline challenges in further elucidating the plant membrane permeome and we provide an outline of novel approaches for the functional characterization of membrane transporters.
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Affiliation(s)
- Nicole Linka
- Institute of Plant Biochemistry, Heinrich-Heine Universität Düsseldorf, Geb. 26.03.01, Universitätsstrasse 1, Düsseldorf, Germany
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Meinke D, Sweeney C, Muralla R. Integrating the genetic and physical maps of Arabidopsis thaliana: identification of mapped alleles of cloned essential (EMB) genes. PLoS One 2009; 4:e7386. [PMID: 19812694 PMCID: PMC2754112 DOI: 10.1371/journal.pone.0007386] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Accepted: 09/15/2009] [Indexed: 12/23/2022] Open
Abstract
The classical genetic map of Arabidopsis includes more than 130 genes with an embryo-defective (emb) mutant phenotype. Many of these essential genes remain to be cloned. Hundreds of additional EMB genes have been cloned and catalogued (www.seedgenes.org) but not mapped. To facilitate EMB gene identification and assess the current level of saturation, we updated the classical map, compared the physical and genetic locations of mapped loci, and performed allelism tests between mapped (but not cloned) and cloned (but not mapped) emb mutants with similar chromosome locations. Two hundred pairwise combinations of genes located on chromosomes 1 and 5 were tested and more than 1100 total crosses were screened. Sixteen of 51 mapped emb mutants examined were found to be disrupted in a known EMB gene. Alleles of a wide range of published EMB genes (YDA, GLA1, TIL1, AtASP38, AtDEK1, EMB506, DG1, OEP80) were discovered. Two EMS mutants isolated 30 years ago, T-DNA mutants with complex insertion sites, and a mutant with an atypical, embryo-specific phenotype were resolved. The frequency of allelism encountered was consistent with past estimates of 500 to 1000 EMB loci. New EMB genes identified among mapped T-DNA insertion mutants included CHC1, which is required for chromatin remodeling, and SHS1/AtBT1, which encodes a plastidial nucleotide transporter similar to the maize Brittle1 protein required for normal endosperm development. Two classical genetic markers (PY, ALB1) were identified based on similar map locations of known genes required for thiamine (THIC) and chlorophyll (PDE166) biosynthesis. The alignment of genetic and physical maps presented here should facilitate the continued analysis of essential genes in Arabidopsis and further characterization of a broad spectrum of mutant phenotypes in a model plant.
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Affiliation(s)
- David Meinke
- Department of Botany, Oklahoma State University, Stillwater, Oklahoma, United States of America.
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Comparot-Moss S, Denyer K. The evolution of the starch biosynthetic pathway in cereals and other grasses. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:2481-92. [PMID: 19505928 DOI: 10.1093/jxb/erp141] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
In most species, the precursor for starch synthesis, ADPglucose, is made exclusively in the plastids by the enzyme ADPglucose pyrophosphorylase (AGPase). However, in the endosperm of grasses, including the economically important cereals, ADPglucose is also made in the cytosol via a cytosolic form of AGPase. Cytosolic ADPglucose is imported into plastids for starch synthesis via an ADPglucose/ADP antiporter (ADPglucose transporter) in the plastid envelope. The genes encoding the two subunits of cytosolic AGPase and the ADPglucose transporter are unique to grasses. In this review, the evolutionary origins of this unique endosperm pathway of ADPglucose synthesis and its functional significance are discussed. It is proposed that the genes encoding the pathway originated from a whole-genome-duplication event in an early ancestor of the grasses.
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Abstract
Plants, restricted by their environment, need to integrate a wide variety of stimuli with their metabolic activity, growth and development. Sugars, generated by photosynthetic carbon fixation, are central in coordinating metabolic fluxes in response to the changing environment and in providing cells and tissues with the necessary energy for continued growth and survival. A complex network of metabolic and hormone signaling pathways are intimately linked to diverse sugar responses. A combination of genetic, cellular and systems analyses have uncovered nuclear HXK1 (hexokinase1) as a pivotal and conserved glucose sensor, directly mediating transcription regulation, while the KIN10/11 energy sensor protein kinases function as master regulators of transcription networks under sugar and energy deprivation conditions. The involvement of disaccharide signals in the regulation of specific cellular processes and the potential role of cell surface receptors in mediating sugar signals add to the complexity. This chapter gives an overview of our current insight in the sugar sensing and signaling network and describes some of the molecular mechanisms involved.
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Affiliation(s)
- Matthew Ramon
- Department of Molecular Biology, Massachusetts General Hospital, Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Filip Rolland
- Department of Biology, Institute of Botany and Microbiology, K.U. Leuven, Kasteelpark Arenberg 31, 3001, Heverlee, Belgium
| | - Jen Sheen
- Department of Molecular Biology, Massachusetts General Hospital, Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
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Kirchberger S, Tjaden J, Neuhaus HE. Characterization of the Arabidopsis Brittle1 transport protein and impact of reduced activity on plant metabolism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 56:51-63. [PMID: 18564385 DOI: 10.1111/j.1365-313x.2008.03583.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The Arabidopsis genome contains a gene (Atbt1) encoding a highly hydrophobic membrane protein of the mitochondrial carrier family, with six predicted transmembrane domains, and showing substantial structural similarity to Brittle1 proteins from maize and potato. We demonstrate that AtBT1 transports AMP, ADP and ATP (but not ADP-glucose), shows a unidirectional mode of transport, and locates to the plastidial membrane and not to the ER as previously proposed. Analysis using an Atbt1 promoter-GUS construct revealed substantial gene expression in rapidly growing root tips and maturating or germinating pollen. Survival of homozygous Atbt1::T-DNA mutants is very limited, and those that do survive produce non-fertile seeds. These observations indicate that no other carrier protein or metabolic mechanism can compensate for the loss of this transporter. Atbt1 RNAi dosage mutants show substantially retarded growth, adenylate levels similar to those of wild-type plants, increased glutamine contents and unchanged starch levels. Interestingly, the growth retardation of Atbt1 RNAi mutant plants was circumvented by adenosine feeding, and was accompanied by increased adenylate levels. Further observations showed the presence of a functional nucleotide salvage pathway in Atbt1 RNAi mutants. In summary, our data indicate that AtBT1 is a plastidial nucleotide uniport carrier protein that is strictly required to export newly synthesized adenylates into the cytosol.
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MESH Headings
- Adenosine/metabolism
- Adenosine Monophosphate/metabolism
- Arabidopsis/genetics
- Arabidopsis/metabolism
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Biological Transport, Active
- DNA, Bacterial/genetics
- DNA, Complementary/genetics
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Gene Expression Profiling
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Plant
- Genes, Plant
- Genes, Reporter
- Mutagenesis, Insertional
- Nucleotide Transport Proteins/genetics
- Nucleotide Transport Proteins/metabolism
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/metabolism
- Plastids/genetics
- Plastids/metabolism
- Promoter Regions, Genetic
- RNA Interference
- RNA, Plant/genetics
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Simon Kirchberger
- Universität Kaiserslautern, Pflanzenphysiologie, Biologie, Erwin-Schrödinger-Strasse, D-67663 Kaiserslautern, Germany
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