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Topitsch A, Schwede T, Pereira J. Outer membrane β-barrel structure prediction through the lens of AlphaFold2. Proteins 2024; 92:3-14. [PMID: 37465978 DOI: 10.1002/prot.26552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 06/26/2023] [Accepted: 07/01/2023] [Indexed: 07/20/2023]
Abstract
Most proteins found in the outer membrane of gram-negative bacteria share a common domain: the transmembrane β-barrel. These outer membrane β-barrels (OMBBs) occur in multiple sizes and different families with a wide range of functions evolved independently by amplification from a pool of homologous ancestral ββ-hairpins. This is part of the reason why predicting their three-dimensional (3D) structure, especially by homology modeling, is a major challenge. Recently, DeepMind's AlphaFold v2 (AF2) became the first structure prediction method to reach close-to-experimental atomic accuracy in CASP even for difficult targets. However, membrane proteins, especially OMBBs, were not abundant during their training, raising the question of how accurate the predictions are for these families. In this study, we assessed the performance of AF2 in the prediction of OMBBs and OMBB-like folds of various topologies using an in-house-developed tool for the analysis of OMBB 3D structures, and barrOs. In agreement with previous studies on other membrane protein classes, our results indicate that AF2 predicts transmembrane β-barrel structures at high accuracy independently of the use of templates, even for novel topologies absent from the training set. These results provide confidence on the models generated by AF2 and open the door to the structural elucidation of novel transmembrane β-barrel topologies identified in high-throughput OMBB annotation studies or designed de novo.
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Affiliation(s)
| | - Torsten Schwede
- Biozentrum, University of Basel, Basel, Switzerland
- SIB Swiss Institute of Bioinformatics, Basel, Switzerland
| | - Joana Pereira
- Biozentrum, University of Basel, Basel, Switzerland
- SIB Swiss Institute of Bioinformatics, Basel, Switzerland
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2
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Linnenbrügger L, Doering L, Lansing H, Fischer K, Eirich J, Finkemeier I, von Schaewen A. Alternative splicing of Arabidopsis G6PD5 recruits NADPH-producing OPPP reactions to the endoplasmic reticulum. FRONTIERS IN PLANT SCIENCE 2022; 13:909624. [PMID: 36119606 PMCID: PMC9478949 DOI: 10.3389/fpls.2022.909624] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
Glucose-6-phosphate dehydrogenase is the rate-limiting enzyme of the oxidative pentose-phosphate pathway (OPPP). The OPPP mainly provides NADPH and sugar-phosphate building blocks for anabolic pathways and is present in all eukaryotes. In plant cells, the irreversible part of the OPPP is found in several compartments. Among the isoforms catalyzing the first OPPP step in Arabidopsis, G6PD1 to G6PD4 target plastids (with G6PD1 being also directed to peroxisomes), whereas G6PD5 and G6PD6 operate in the cytosol. We noticed that alternative splice forms G6PD5.4 and G6PD5.5 encode N-terminally extended proteoforms. Compared to G6PD5.1, RT-PCR signals differed and fluorescent reporter fusions expressed in Arabidopsis protoplasts accumulated in distinct intracellular sites. Co-expression with organelle-specific markers revealed that the G6PD5.4 and G6PD5.5 proteoforms label different subdomains of the endoplasmic reticulum (ER), and analysis of C-terminal roGFP fusions showed that their catalytic domains face the cytosol. In g6pd5-1 g6pd6-2 mutant protoplasts lacking cytosolic G6PDH activity, the ER-bound proteoforms were both active and thus able to form homomers. Among the Arabidopsis 6-phosphogluconolactonases (catalyzing the second OPPP step), we noticed that isoform PGL2 carries a C-terminal CaaX motif that may be prenylated for membrane attachment. Reporter-PGL2 fusions co-localized with G6PD5.4 in ER subdomains, which was abolished by Cys-to-Ser exchange in the 256CSIL motif. Among the Arabidopsis 6-phosphogluconate dehydrogenases (catalyzing the third OPPP step), S-acylated peptides were detected for all three isoforms in a recent palmitoylome, with dual cytosolic/peroxisomal PGD2 displaying three sites. Co-expression of GFP-PGD2 diminished crowding of OFP-G6PD5.4 at the ER, independent of PGL2's presence. Upon pull-down of GFP-G6PD5.4, not only unlabeled PGD2 and PGL2 were enriched, but also enzymes that depend on NADPH provision at the ER, indicative of physical interaction with the OPPP enzymes. When membrane-bound G6PD5.5 and 5.4 variants were co-expressed with KCR1 (ketoacyl-CoA reductase, involved in fatty acid elongation), ATR1 (NADPH:cytochrome-P450 oxidoreductase), or pulled C4H/CYP73A5 (cinnamate 4-hydroxylase) as indirectly (via ATR) NADPH-dependent cytochrome P450 enzyme, co-localization in ER subdomains was observed. Thus, alternative splicing of G6PD5 can direct the NADPH-producing OPPP reactions to the cytosolic face of the ER, where they may operate as membrane-bound metabolon to support several important biosynthetic pathways of plant cells.
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Affiliation(s)
- Loreen Linnenbrügger
- Department of Biology, Molecular Physiology of Plants, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Lennart Doering
- Department of Biology, Molecular Physiology of Plants, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Hannes Lansing
- Department of Biology, Molecular Physiology of Plants, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Kerstin Fischer
- Department of Biology, Molecular Physiology of Plants, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Jürgen Eirich
- Department of Biology, Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Iris Finkemeier
- Department of Biology, Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Antje von Schaewen
- Department of Biology, Molecular Physiology of Plants, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
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3
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Rottet S, Förster B, Hee WY, Rourke LM, Price GD, Long BM. Engineered Accumulation of Bicarbonate in Plant Chloroplasts: Known Knowns and Known Unknowns. FRONTIERS IN PLANT SCIENCE 2021; 12:727118. [PMID: 34531888 PMCID: PMC8438413 DOI: 10.3389/fpls.2021.727118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 08/06/2021] [Indexed: 05/10/2023]
Abstract
Heterologous synthesis of a biophysical CO2-concentrating mechanism (CCM) in plant chloroplasts offers significant potential to improve the photosynthetic efficiency of C3 plants and could translate into substantial increases in crop yield. In organisms utilizing a biophysical CCM, this mechanism efficiently surrounds a high turnover rate Rubisco with elevated CO2 concentrations to maximize carboxylation rates. A critical feature of both native biophysical CCMs and one engineered into a C3 plant chloroplast is functional bicarbonate (HCO3 -) transporters and vectorial CO2-to-HCO3 - converters. Engineering strategies aim to locate these transporters and conversion systems to the C3 chloroplast, enabling elevation of HCO3 - concentrations within the chloroplast stroma. Several CCM components have been identified in proteobacteria, cyanobacteria, and microalgae as likely candidates for this approach, yet their successful functional expression in C3 plant chloroplasts remains elusive. Here, we discuss the challenges in expressing and regulating functional HCO3 - transporter, and CO2-to-HCO3 - converter candidates in chloroplast membranes as an essential step in engineering a biophysical CCM within plant chloroplasts. We highlight the broad technical and physiological concerns which must be considered in proposed engineering strategies, and present our current status of both knowledge and knowledge-gaps which will affect successful engineering outcomes.
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Affiliation(s)
- Sarah Rottet
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, Canberra, ACT, Australia
| | - Britta Förster
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Wei Yih Hee
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, Canberra, ACT, Australia
| | - Loraine M. Rourke
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, Canberra, ACT, Australia
| | - G. Dean Price
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, Canberra, ACT, Australia
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Benedict M. Long
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, Canberra, ACT, Australia
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, Australia
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4
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Abstract
All currently known architectures of outer-membrane beta barrels (OMBBs) have only one barrel. While the vast majority function as oligomers, with barrels from different chains packing against each other in the membrane, it was assumed that these multiple chains are needed to form multibarrel structures. And yet, here we show that multibarrel chains exist. Using state-of-the-art sequence and structure analysis tools, we report the discovery of more than 30 multibarrel architectures from gram-negative bacteria. The discovery of these architectures reveals another interesting chapter in OMBB evolution and has implications for protein engineering. The evolutionary advantages of multibarrels are yet to be discovered. Outer-membrane beta barrels (OMBBs) are found in the outer membrane of gram-negative bacteria and eukaryotic organelles. OMBBs fold as antiparallel β-sheets that close onto themselves, forming pores that traverse the membrane. Currently known structures include only one barrel, of 8 to 36 strands, per chain. The lack of multi-OMBB chains is surprising, as most OMBBs form oligomers, and some function only in this state. Using a combination of sensitive sequence comparison methods and coevolutionary analysis tools, we identify many proteins combining multiple beta barrels within a single chain; combinations that include eight-stranded barrels prevail. These multibarrels seem to be the result of independent, lineage-specific fusion and amplification events. The absence of multibarrels that are universally conserved in bacteria with an outer membrane, coupled with their frequent de novo genesis, suggests that their functions are not essential but rather beneficial in specific environments. Adjacent barrels of complementary function within the same chain may allow for functions beyond those of the individual barrels.
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5
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Speijer D. Zombie ideas about early endosymbiosis: Which entry mechanisms gave us the "endo" in different endosymbionts? Bioessays 2021; 43:e2100069. [PMID: 34008202 DOI: 10.1002/bies.202100069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/08/2021] [Accepted: 04/09/2021] [Indexed: 01/31/2023]
Abstract
Recently, a review regarding the mechanics and evolution of mitochondrial fission appeared in Nature. Surprisingly, it stated authoritatively that the mitochondrial outer membrane, in contrast with the inner membrane of bacterial descent, was acquired from the host, presumably during uptake. However, it has been known for quite some time that this membrane was also derived from the Gram-negative, alpha-proteobacterium related precursor of present-day mitochondria. The zombie idea of the host membrane still surrounding the endosymbiont is not only wrong, but more importantly, might hamper the proper conception of possible scenarios of eukaryogenesis. Why? Because it steers the imagination not only with regard to possible uptake mechanisms, but also regarding what went on before. Here I critically discuss both the evidence for the continuity of the bacterial outer membrane, the reasons for the persistence of the erroneous host membrane hypothesis and the wider implications of these misconceptions for the ideas regarding events occurring during the first steps towards the evolution of the eukaryotes and later major eukaryotic differentiations. I will also highlight some of the latest insights regarding different instances of endosymbiont evolution.
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Affiliation(s)
- Dave Speijer
- Department of Medical Biochemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
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6
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Eisenhut M. Manganese Homeostasis in Cyanobacteria. PLANTS 2019; 9:plants9010018. [PMID: 31877921 PMCID: PMC7020235 DOI: 10.3390/plants9010018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 12/24/2022]
Abstract
Manganese (Mn) is essential for life on earth. As a catalyst of the water oxidation reaction within photosystem II, the trace metal is responsible for the evolution of virtually all oxygen in the earth’s atmosphere. Mn acts furthermore as an activator or cofactor of numerous enzymes involved in reactive oxygen species scavenging or central and secondary metabolism. While the sufficient supply of oxygenic photosynthetic organisms with Mn is obvious for maintaining photosynthetic activity, the avoidance of cellular Mn overload is also critical. In this review, current knowledge about the Mn homeostasis network in the model cyanobacterium Synechocystis sp. PCC 6803 is presented, including transporters and regulators.
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Affiliation(s)
- Marion Eisenhut
- Biochemie der Pflanzen, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
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7
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Vigani G, Solti ÏDM, Thomine SB, Philippar K. Essential and Detrimental - an Update on Intracellular Iron Trafficking and Homeostasis. PLANT & CELL PHYSIOLOGY 2019; 60:1420-1439. [PMID: 31093670 DOI: 10.1093/pcp/pcz091] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/06/2019] [Indexed: 05/22/2023]
Abstract
Chloroplasts, mitochondria and vacuoles represent characteristic organelles of the plant cell, with a predominant function in cellular metabolism. Chloroplasts are the site of photosynthesis and therefore basic and essential for photoautotrophic growth of plants. Mitochondria produce energy during respiration and vacuoles act as internal waste and storage compartments. Moreover, chloroplasts and mitochondria are sites for the biosynthesis of various compounds of primary and secondary metabolism. For photosynthesis and energy generation, the internal membranes of chloroplasts and mitochondria are equipped with electron transport chains. To perform proper electron transfer and several biosynthetic functions, both organelles contain transition metals and here iron is by far the most abundant. Although iron is thus essential for plant growth and development, it becomes toxic when present in excess and/or in its free, ionic form. The harmful effect of the latter is caused by the generation of oxidative stress. As a consequence, iron transport and homeostasis have to be tightly controlled during plant growth and development. In addition to the corresponding transport and homeostasis proteins, the vacuole plays an important role as an intracellular iron storage and release compartment at certain developmental stages. In this review, we will summarize current knowledge on iron transport and homeostasis in chloroplasts, mitochondria and vacuoles. In addition, we aim to integrate the physiological impact of intracellular iron homeostasis on cellular and developmental processes.
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Affiliation(s)
- Gianpiero Vigani
- Plant Physiology Unit, Department of Life Sciences and Systems Biology, University of Turin, via Quarello 15/A, Turin I, Italy
| | - Ï Dï M Solti
- Department of Plant Physiology and Molecular Plant Biology, E�tv�s Lor�nd University, Budapest H, Hungary
| | - Sï Bastien Thomine
- Institut de Biologie Int�grative de la Cellule, CNRS, Avenue de la Terrasse, Gif-sur-Yvette, France
| | - Katrin Philippar
- Plant Biology, Center for Human- and Molecular Biology (ZHMB), Saarland University, Campus A2.4, Saarbr�cken D, Germany
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8
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Voith von Voithenberg L, Park J, Stübe R, Lux C, Lee Y, Philippar K. A Novel Prokaryote-Type ECF/ABC Transporter Module in Chloroplast Metal Homeostasis. FRONTIERS IN PLANT SCIENCE 2019; 10:1264. [PMID: 31736987 PMCID: PMC6828968 DOI: 10.3389/fpls.2019.01264] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 09/11/2019] [Indexed: 05/18/2023]
Abstract
During evolution, chloroplasts, which originated by endosymbiosis of a prokaryotic ancestor of today's cyanobacteria with a eukaryotic host cell, were established as the site for photosynthesis. Therefore, chloroplast organelles are loaded with transition metals including iron, copper, and manganese, which are essential for photosynthetic electron transport due to their redox capacity. Although transport, storage, and cofactor-assembly of metal ions in chloroplasts are tightly controlled and crucial throughout plant growth and development, knowledge on the molecular nature of chloroplast metal-transport proteins is still fragmentary. Here, we characterized the soluble, ATP-binding ABC-transporter subunits ABCI10 and ABCI11 in Arabidopsis thaliana, which show similarities to components of prokaryotic, multisubunit ABC transporters. Both ABCI10 and ABCI11 proteins appear to be strongly attached to chloroplast-intrinsic membranes, most likely inner envelopes for ABCI10 and possibly plastoglobuli for ABCI11. Loss of ABCI10 and ABCI11 gene products in Arabidopsis leads to extremely dwarfed, albino plants showing impaired chloroplast biogenesis and deregulated metal homeostasis. Further, we identified the membrane-intrinsic protein ABCI12 as potential interaction partner for ABCI10 in the inner envelope. Our results suggest that ABCI12 inserts into the chloroplast inner envelope membrane most likely with five predicted α-helical transmembrane domains and represents the membrane-intrinsic subunit of a prokaryotic-type, energy-coupling factor (ECF) ABC-transporter complex. In bacteria, these multisubunit ECF importers are widely distributed for the uptake of nickel and cobalt metal ions as well as for import of vitamins and several other metabolites. Therefore, we propose that ABCI10 (as the ATPase A-subunit) and ABCI12 (as the membrane-intrinsic, energy-coupling T-subunit) are part of a novel, chloroplast envelope-localized, AAT energy-coupling module of a prokaryotic-type ECF transporter, most likely involved in metal ion uptake.
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Affiliation(s)
| | - Jiyoung Park
- Department of Life Science, Pohang University of Science and Technology, Pohang, South Korea
| | - Roland Stübe
- Plant Biochemistry and Physiology, Department of Biology I, LMU München, Planegg-Martinsried, Germany
| | - Christopher Lux
- Plant Biology, Center for Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany
| | - Youngsook Lee
- Department of Life Science, Pohang University of Science and Technology, Pohang, South Korea
| | - Katrin Philippar
- Plant Biology, Center for Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany
- *Correspondence: Katrin Philippar,
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9
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Voith von Voithenberg L, Park J, Stübe R, Lux C, Lee Y, Philippar K. A Novel Prokaryote-Type ECF/ABC Transporter Module in Chloroplast Metal Homeostasis. FRONTIERS IN PLANT SCIENCE 2019; 10:1264. [PMID: 31736987 DOI: 10.3389/fpls201901264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 09/11/2019] [Indexed: 05/22/2023]
Abstract
During evolution, chloroplasts, which originated by endosymbiosis of a prokaryotic ancestor of today's cyanobacteria with a eukaryotic host cell, were established as the site for photosynthesis. Therefore, chloroplast organelles are loaded with transition metals including iron, copper, and manganese, which are essential for photosynthetic electron transport due to their redox capacity. Although transport, storage, and cofactor-assembly of metal ions in chloroplasts are tightly controlled and crucial throughout plant growth and development, knowledge on the molecular nature of chloroplast metal-transport proteins is still fragmentary. Here, we characterized the soluble, ATP-binding ABC-transporter subunits ABCI10 and ABCI11 in Arabidopsis thaliana, which show similarities to components of prokaryotic, multisubunit ABC transporters. Both ABCI10 and ABCI11 proteins appear to be strongly attached to chloroplast-intrinsic membranes, most likely inner envelopes for ABCI10 and possibly plastoglobuli for ABCI11. Loss of ABCI10 and ABCI11 gene products in Arabidopsis leads to extremely dwarfed, albino plants showing impaired chloroplast biogenesis and deregulated metal homeostasis. Further, we identified the membrane-intrinsic protein ABCI12 as potential interaction partner for ABCI10 in the inner envelope. Our results suggest that ABCI12 inserts into the chloroplast inner envelope membrane most likely with five predicted α-helical transmembrane domains and represents the membrane-intrinsic subunit of a prokaryotic-type, energy-coupling factor (ECF) ABC-transporter complex. In bacteria, these multisubunit ECF importers are widely distributed for the uptake of nickel and cobalt metal ions as well as for import of vitamins and several other metabolites. Therefore, we propose that ABCI10 (as the ATPase A-subunit) and ABCI12 (as the membrane-intrinsic, energy-coupling T-subunit) are part of a novel, chloroplast envelope-localized, AAT energy-coupling module of a prokaryotic-type ECF transporter, most likely involved in metal ion uptake.
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Affiliation(s)
| | - Jiyoung Park
- Department of Life Science, Pohang University of Science and Technology, Pohang, South Korea
| | - Roland Stübe
- Plant Biochemistry and Physiology, Department of Biology I, LMU München, Planegg-Martinsried, Germany
| | - Christopher Lux
- Plant Biology, Center for Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany
| | - Youngsook Lee
- Department of Life Science, Pohang University of Science and Technology, Pohang, South Korea
| | - Katrin Philippar
- Plant Biology, Center for Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany
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10
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Pereira J, Lupas AN. The Origin of Mitochondria-Specific Outer Membrane β-Barrels from an Ancestral Bacterial Fragment. Genome Biol Evol 2018; 10:2759-2765. [PMID: 30265295 PMCID: PMC6193526 DOI: 10.1093/gbe/evy216] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2018] [Indexed: 12/26/2022] Open
Abstract
Outer membrane β-barrels (OMBBs) are toroidal arrays of antiparallel β-strands that span the outer membrane of Gram-negative bacteria and eukaryotic organelles. Although homologous, most families of bacterial OMBBs evolved through the independent amplification of an ancestral ββ-hairpin. In mitochondria, one family (SAM50) has a clear bacterial ancestry; the origin of the other family, consisting of 19-stranded OMBBs found only in mitochondria (MOMBBs), is substantially unclear. In a large-scale comparison of mitochondrial and bacterial OMBBs, we find evidence that the common ancestor of all MOMBBs emerged by the amplification of a double ββ-hairpin of bacterial origin, probably at the time of the Last Eukaryotic Common Ancestor. Thus, MOMBBs are indeed descended from bacterial OMBBs, but their fold formed independently in the proto-mitochondria, possibly in response to the need for a general-purpose polypeptide importer. This occurred by a process of amplification, despite the final fold having a prime number of strands.
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Affiliation(s)
- Joana Pereira
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, Tübingen, Germany
| | - Andrei N Lupas
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, Tübingen, Germany
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11
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Könnel A, Bugaeva W, Gügel IL, Philippar K. BANFF: bending of bilayer membranes by amphiphilic α-helices is necessary for form and function of organelles 1. Biochem Cell Biol 2018; 97:243-256. [PMID: 30208283 DOI: 10.1139/bcb-2018-0150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
By binding to and inserting into the lipid bilayer, amphiphilic α-helices of proteins are involved in the curvature of biological membranes in all organisms. In particular, they are involved in establishing the complex membrane architecture of intracellular organelles like the endoplasmatic reticulum, Golgi apparatus, mitochondria, and chloroplasts. Thus, amphiphilic α-helices are essential for maintenance of cellular metabolism and fitness of organisms. Here we focus on the structure and function of membrane-intrinsic proteins, which are involved in membrane curvature by amphiphilic α-helices, in mitochondria and chloroplasts of the eukaryotic model organisms yeast and Arabidopsis thaliana. Further, we propose a model for transport of fatty acids and lipid compounds across the envelope of chloroplasts in which amphiphilic α-helices might play a role.
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Affiliation(s)
- Anne Könnel
- a Center for Human- and Molecular Biology (ZHMB) - Plant Biology, Saarland University, Campus A 2.4, 66123 Saarbrücken, Germany
| | - Wassilina Bugaeva
- a Center for Human- and Molecular Biology (ZHMB) - Plant Biology, Saarland University, Campus A 2.4, 66123 Saarbrücken, Germany
| | - Irene L Gügel
- b Department of Biology I - Botany, Ludwig-Maximilians University München, Großhaderner-Str. 2, 82152 Planegg-Martinsried, Germany
| | - Katrin Philippar
- a Center for Human- and Molecular Biology (ZHMB) - Plant Biology, Saarland University, Campus A 2.4, 66123 Saarbrücken, Germany
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12
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Becker T, Wagner R. Mitochondrial Outer Membrane Channels: Emerging Diversity in Transport Processes. Bioessays 2018; 40:e1800013. [DOI: 10.1002/bies.201800013] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 03/29/2018] [Indexed: 01/06/2023]
Affiliation(s)
- Thomas Becker
- Faculty of MedicineInstitute of Biochemistry and Molecular Biology, ZBMZUniversity of FreiburgFreiburgD‐79104Germany
- BIOSS Centre for Biological Signalling StudiesUniversity of FreiburgFreiburgD‐79104Germany
| | - Richard Wagner
- Biophysics, Life Sciences & ChemistryJacobs University BremenBremenD‐28759Germany
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13
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Chang J, Chen Y, Xu Z, Wang Z, Zeng Q, Fan H. Switchable Control of Antibiotic Activity: A Shape-Shifting “Tail” Strategy. Bioconjug Chem 2017; 29:74-82. [DOI: 10.1021/acs.bioconjchem.7b00599] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Jinming Chang
- Key
Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, P.R. China
| | - Yi Chen
- Key
Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, P.R. China
- Department
of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Zhou Xu
- Key
Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, P.R. China
| | - Zhonghui Wang
- Key
Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, P.R. China
| | - Qi Zeng
- Key
Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, P.R. China
| | - Haojun Fan
- Key
Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, P.R. China
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14
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Zang X, Geng X, Liu K, Wang F, Liu Z, Zhang L, Zhao Y, Tian X, Hu Z, Yao Y, Ni Z, Xin M, Sun Q, Peng H. Ectopic expression of TaOEP16-2-5B, a wheat plastid outer envelope protein gene, enhances heat and drought stress tolerance in transgenic Arabidopsis plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 258:1-11. [PMID: 28330552 DOI: 10.1016/j.plantsci.2017.01.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 12/15/2016] [Accepted: 01/18/2017] [Indexed: 05/11/2023]
Abstract
Abiotic stresses, such as heat and drought, are major environmental factors restricting crop productivity and quality worldwide. A plastid outer envelope protein gene, TaOEP16-2, was identified from our previous transcriptome analysis [1,2]. In this study, the isolation and functional characterization of the TaOEP16-2 gene was reported. Three homoeologous sequences of TaOEP16-2 were isolated from hexaploid wheat, which were localized on the chromosomes 5A, 5B and 5D, respectively. These three homoeologues exhibited different expression patterns under heat stress conditions, TaOEP16-2-5B was the dominant one, and TaOEP16-2-5B was selected for further analysis. Compared with wild type (WT) plants, transgenic Arabidopsis plants overexpressing the TaOEP16-2-5B gene exhibited enhanced tolerance to heat stress, which was supported by improved survival rate, strengthened cell membrane stability and increased sucrose content. It was also found that TaOEP16-2 was induced by drought stress and involved in drought stress tolerance. TaOEP16-2-5B has the same function in ABA-controlled seed germination as AtOEP16-2. Our results suggest that TaOEP16-2-5B plays an important role in heat and drought stress tolerance, and could be utilized in transgenic breeding of wheat and other crop plants.
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Affiliation(s)
- Xinshan Zang
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Xiaoli Geng
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Kelu Liu
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Fei Wang
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhenshan Liu
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Liyuan Zhang
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yue Zhao
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Xuejun Tian
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhaorong Hu
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yingyin Yao
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhongfu Ni
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Mingming Xin
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Qixin Sun
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Huiru Peng
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China.
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Solti Á, Kovács K, Müller B, Vázquez S, Hamar É, Pham HD, Tóth B, Abadía J, Fodor F. Does a voltage-sensitive outer envelope transport mechanism contributes to the chloroplast iron uptake? PLANTA 2016; 244:1303-1313. [PMID: 27541495 DOI: 10.1007/s00425-016-2586-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 08/10/2016] [Indexed: 05/22/2023]
Abstract
Based on the effects of inorganic salts on chloroplast Fe uptake, the presence of a voltage-dependent step is proposed to play a role in Fe uptake through the outer envelope. Although iron (Fe) plays a crucial role in chloroplast physiology, only few pieces of information are available on the mechanisms of chloroplast Fe acquisition. Here, the effect of inorganic salts on the Fe uptake of intact chloroplasts was tested, assessing Fe and transition metal uptake using bathophenantroline-based spectrophotometric detection and plasma emission-coupled mass spectrometry, respectively. The microenvironment of Fe was studied by Mössbauer spectroscopy. Transition metal cations (Cd2+, Zn2+, and Mn2+) enhanced, whereas oxoanions (NO3-, SO42-, and BO33-) reduced the chloroplast Fe uptake. The effect was insensitive to diuron (DCMU), an inhibitor of chloroplast inner envelope-associated Fe uptake. The inorganic salts affected neither Fe forms in the uptake assay buffer nor those incorporated into the chloroplasts. The significantly lower Zn and Mn uptake compared to that of Fe indicates that different mechanisms/transporters are involved in their acquisition. The enhancing effect of transition metals on chloroplast Fe uptake is likely related to outer envelope-associated processes, since divalent metal cations are known to inhibit Fe2+ transport across the inner envelope. Thus, a voltage-dependent step is proposed to play a role in Fe uptake through the chloroplast outer envelope on the basis of the contrasting effects of transition metal cations and oxoaninons.
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Affiliation(s)
- Ádám Solti
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Faculty of Sciences, Eötvös Loránd University, Pázmány P. Sétány 1/C, Budapest, 1117, Hungary.
| | - Krisztina Kovács
- Laboratory of Nuclear Chemistry, Department of Analytical Chemistry, Institute of Chemistry, Faculty of Sciences, Eötvös Loránd University, Pázmány P. Sétány 1/A, Budapest, 1117, Hungary
| | - Brigitta Müller
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Faculty of Sciences, Eötvös Loránd University, Pázmány P. Sétány 1/C, Budapest, 1117, Hungary
| | - Saúl Vázquez
- Department of Plant Nutrition, Aula Dei Experimental Station, Spanish Council for Scientific Research (CSIC), P.O. Box 13034, 50080, Saragossa, Spain
- Faculty of Science, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire, LE12 5RD, UK
| | - Éva Hamar
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Faculty of Sciences, Eötvös Loránd University, Pázmány P. Sétány 1/C, Budapest, 1117, Hungary
| | - Hong Diep Pham
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Faculty of Sciences, Eötvös Loránd University, Pázmány P. Sétány 1/C, Budapest, 1117, Hungary
| | - Brigitta Tóth
- Department of Agricultural Botany, Crop Physiology and Biotechnology, Institute of Crop Sciences, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Böszörményi út 138, Debrecen, 4032, Hungary
| | - Javier Abadía
- Department of Plant Nutrition, Aula Dei Experimental Station, Spanish Council for Scientific Research (CSIC), P.O. Box 13034, 50080, Saragossa, Spain
| | - Ferenc Fodor
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Faculty of Sciences, Eötvös Loránd University, Pázmány P. Sétány 1/C, Budapest, 1117, Hungary
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16
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Harsman A, Schock A, Hemmis B, Wahl V, Jeshen I, Bartsch P, Schlereth A, Pertl-Obermeyer H, Goetze TA, Soll J, Philippar K, Wagner R. OEP40, a Regulated Glucose-permeable β-Barrel Solute Channel in the Chloroplast Outer Envelope Membrane. J Biol Chem 2016; 291:17848-60. [PMID: 27339897 DOI: 10.1074/jbc.m115.712398] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 12/20/2022] Open
Abstract
Chloroplasts and mitochondria are unique endosymbiotic cellular organelles surrounded by two membranes. Essential metabolic networking between these compartments and their hosting cells requires the exchange of a large number of biochemical pathway intermediates in a directed and coordinated fashion across their inner and outer envelope membranes. Here, we describe the identification and functional characterization of a highly specific, regulated solute channel in the outer envelope of chloroplasts, named OEP40. Loss of OEP40 function in Arabidopsis thaliana results in early flowering under cold temperature. The reconstituted recombinant OEP40 protein forms a high conductance β-barrel ion channel with subconductant states in planar lipid bilayers. The OEP40 channel is slightly cation-selective PK+/PCl- ≈ 4:1 and rectifying (i⃗/i⃖ ≅ 2) with a slope conductance of Ḡmax ≅ 690 picosiemens. The OEP40 channel has a restriction zone diameter of ≅1.4 nm and is permeable for glucose, glucose 1-phosphate and glucose 6-phosphate, but not for maltose. Moreover, channel properties are regulated by trehalose 6-phosphate, which cannot permeate. Altogether, our results indicate that OEP40 is a "glucose-gate" in the outer envelope membrane of chloroplasts, facilitating selective metabolite exchange between chloroplasts and the surrounding cell.
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Affiliation(s)
- Anke Harsman
- From the Institute of Biophysics, Department of Biology, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück
| | - Annette Schock
- the Chair of Plant Biochemistry and Physiology, Department Biology I-Botany, Ludwig-Maximilians-University München, Grosshadernerstrasse 2-4, D-82152 Planegg-Martinsried, the Munich Centre for Integrated Protein Science, Ludwig-Maximilians-University München, D-81377 München, and
| | - Birgit Hemmis
- From the Institute of Biophysics, Department of Biology, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück
| | - Vanessa Wahl
- the Department of Metabolic Networks, Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Ingrid Jeshen
- the Chair of Plant Biochemistry and Physiology, Department Biology I-Botany, Ludwig-Maximilians-University München, Grosshadernerstrasse 2-4, D-82152 Planegg-Martinsried, the Munich Centre for Integrated Protein Science, Ludwig-Maximilians-University München, D-81377 München, and
| | - Philipp Bartsch
- From the Institute of Biophysics, Department of Biology, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück
| | - Armin Schlereth
- the Department of Metabolic Networks, Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Heidi Pertl-Obermeyer
- the Chair of Plant Biochemistry and Physiology, Department Biology I-Botany, Ludwig-Maximilians-University München, Grosshadernerstrasse 2-4, D-82152 Planegg-Martinsried, the Munich Centre for Integrated Protein Science, Ludwig-Maximilians-University München, D-81377 München, and
| | - Tom Alexander Goetze
- the Chair of Plant Biochemistry and Physiology, Department Biology I-Botany, Ludwig-Maximilians-University München, Grosshadernerstrasse 2-4, D-82152 Planegg-Martinsried, the Munich Centre for Integrated Protein Science, Ludwig-Maximilians-University München, D-81377 München, and
| | - Jürgen Soll
- the Chair of Plant Biochemistry and Physiology, Department Biology I-Botany, Ludwig-Maximilians-University München, Grosshadernerstrasse 2-4, D-82152 Planegg-Martinsried, the Munich Centre for Integrated Protein Science, Ludwig-Maximilians-University München, D-81377 München, and
| | - Katrin Philippar
- the Chair of Plant Biochemistry and Physiology, Department Biology I-Botany, Ludwig-Maximilians-University München, Grosshadernerstrasse 2-4, D-82152 Planegg-Martinsried, the Munich Centre for Integrated Protein Science, Ludwig-Maximilians-University München, D-81377 München, and
| | - Richard Wagner
- From the Institute of Biophysics, Department of Biology, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück,
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Carraretto L, Teardo E, Checchetto V, Finazzi G, Uozumi N, Szabo I. Ion Channels in Plant Bioenergetic Organelles, Chloroplasts and Mitochondria: From Molecular Identification to Function. MOLECULAR PLANT 2016; 9:371-395. [PMID: 26751960 DOI: 10.1016/j.molp.2015.12.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/22/2015] [Accepted: 12/01/2015] [Indexed: 06/05/2023]
Abstract
Recent technical advances in electrophysiological measurements, organelle-targeted fluorescence imaging, and organelle proteomics have pushed the research of ion transport a step forward in the case of the plant bioenergetic organelles, chloroplasts and mitochondria, leading to the molecular identification and functional characterization of several ion transport systems in recent years. Here we focus on channels that mediate relatively high-rate ion and water flux and summarize the current knowledge in this field, focusing on targeting mechanisms, proteomics, electrophysiology, and physiological function. In addition, since chloroplasts evolved from a cyanobacterial ancestor, we give an overview of the information available about cyanobacterial ion channels and discuss the evolutionary origin of chloroplast channels. The recent molecular identification of some of these ion channels allowed their physiological functions to be studied using genetically modified Arabidopsis plants and cyanobacteria. The view is emerging that alteration of chloroplast and mitochondrial ion homeostasis leads to organelle dysfunction, which in turn significantly affects the energy metabolism of the whole organism. Clear-cut identification of genes encoding for channels in these organelles, however, remains a major challenge in this rapidly developing field. Multiple strategies including bioinformatics, cell biology, electrophysiology, use of organelle-targeted ion-sensitive probes, genetics, and identification of signals eliciting specific ion fluxes across organelle membranes should provide a better understanding of the physiological role of organellar channels and their contribution to signaling pathways in plants in the future.
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Affiliation(s)
- Luca Carraretto
- Department of Biology, University of Padova, Padova 35121, Italy
| | - Enrico Teardo
- Department of Biology, University of Padova, Padova 35121, Italy; CNR Institute of Neuroscience, University of Padova, Padova 35121, Italy
| | | | - Giovanni Finazzi
- UMR 5168 Laboratoire de Physiologie Cellulaire Végétale (LPCV) CNRS/ UJF / INRA / CEA, Institut de Recherches en Technologies et Sciences pour le Vivant (iRTSV), CEA Grenoble, 38054 Grenoble, France.
| | - Nobuyuki Uozumi
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aobayama 6-6-07, Sendai 980-8579, Japan.
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padova 35121, Italy; CNR Institute of Neuroscience, University of Padova, Padova 35121, Italy.
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18
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Klasek L, Inoue K. Dual Protein Localization to the Envelope and Thylakoid Membranes Within the Chloroplast. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 323:231-63. [PMID: 26944623 DOI: 10.1016/bs.ircmb.2015.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The chloroplast houses various metabolic processes essential for plant viability. This organelle originated from an ancestral cyanobacterium via endosymbiosis and maintains the three membranes of its progenitor. Among them, the outer envelope membrane functions mainly in communication with cytoplasmic components while the inner envelope membrane houses selective transport of various metabolites and the biosynthesis of several compounds, including membrane lipids. These two envelope membranes also play essential roles in import of nuclear-encoded proteins and in organelle division. The third membrane, the internal membrane system known as the thylakoid, houses photosynthetic electron transport and chemiosmotic phosphorylation. The inner envelope and thylakoid membranes share similar lipid composition. Specific targeting pathways determine their defined proteomes and, thus, their distinct functions. Nonetheless, several proteins have been shown to exist in both the envelope and thylakoid membranes. These proteins include those that play roles in protein transport, tetrapyrrole biosynthesis, membrane dynamics, or transport of nucleotides or inorganic phosphate. In this review, we summarize the current knowledge about proteins localized to both the envelope and thylakoid membranes in the chloroplast, discussing their roles in each membrane and potential mechanisms of their dual localization. Addressing the unanswered questions about these dual-localized proteins should help advance our understanding of chloroplast development, protein transport, and metabolic regulation.
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Affiliation(s)
- Laura Klasek
- Department of Plant Sciences, University of California at Davis, Davis, CA, United States of America
| | - Kentaro Inoue
- Department of Plant Sciences, University of California at Davis, Davis, CA, United States of America.
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19
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López-Millán AF, Duy D, Philippar K. Chloroplast Iron Transport Proteins - Function and Impact on Plant Physiology. FRONTIERS IN PLANT SCIENCE 2016; 7:178. [PMID: 27014281 DOI: 10.3389/fpls201600178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 02/02/2016] [Indexed: 05/22/2023]
Abstract
Chloroplasts originated about three billion years ago by endosymbiosis of an ancestor of today's cyanobacteria with a mitochondria-containing host cell. During evolution chloroplasts of higher plants established as the site for photosynthesis and thus became the basis for all life dependent on oxygen and carbohydrate supply. To fulfill this task, plastid organelles are loaded with the transition metals iron, copper, and manganese, which due to their redox properties are essential for photosynthetic electron transport. In consequence, chloroplasts for example represent the iron-richest system in plant cells. However, improvement of oxygenic photosynthesis in turn required adaptation of metal transport and homeostasis since metal-catalyzed generation of reactive oxygen species (ROS) causes oxidative damage. This is most acute in chloroplasts, where radicals and transition metals are side by side and ROS-production is a usual feature of photosynthetic electron transport. Thus, on the one hand when bound by proteins, chloroplast-intrinsic metals are a prerequisite for photoautotrophic life, but on the other hand become toxic when present in their highly reactive, radical generating, free ionic forms. In consequence, transport, storage and cofactor-assembly of metal ions in plastids have to be tightly controlled and are crucial throughout plant growth and development. In the recent years, proteins for iron transport have been isolated from chloroplast envelope membranes. Here, we discuss their putative functions and impact on cellular metal homeostasis as well as photosynthetic performance and plant metabolism. We further consider the potential of proteomic analyses to identify new players in the field.
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Affiliation(s)
- Ana F López-Millán
- Department of Pediatrics, Children's Nutrition Research Center, Baylor College of Medicine, United States Department of Agriculture/Agricultural Research Service, Houston TX, USA
| | - Daniela Duy
- Plastid Fatty Acid and Iron Transport - Plant Biochemistry and Physiology, Department Biology I, Ludwig-Maximilians-University of Munich Munich, Germany
| | - Katrin Philippar
- Plastid Fatty Acid and Iron Transport - Plant Biochemistry and Physiology, Department Biology I, Ludwig-Maximilians-University of Munich Munich, Germany
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20
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López-Millán AF, Duy D, Philippar K. Chloroplast Iron Transport Proteins - Function and Impact on Plant Physiology. FRONTIERS IN PLANT SCIENCE 2016; 7:178. [PMID: 27014281 PMCID: PMC4780311 DOI: 10.3389/fpls.2016.00178] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 02/02/2016] [Indexed: 05/08/2023]
Abstract
Chloroplasts originated about three billion years ago by endosymbiosis of an ancestor of today's cyanobacteria with a mitochondria-containing host cell. During evolution chloroplasts of higher plants established as the site for photosynthesis and thus became the basis for all life dependent on oxygen and carbohydrate supply. To fulfill this task, plastid organelles are loaded with the transition metals iron, copper, and manganese, which due to their redox properties are essential for photosynthetic electron transport. In consequence, chloroplasts for example represent the iron-richest system in plant cells. However, improvement of oxygenic photosynthesis in turn required adaptation of metal transport and homeostasis since metal-catalyzed generation of reactive oxygen species (ROS) causes oxidative damage. This is most acute in chloroplasts, where radicals and transition metals are side by side and ROS-production is a usual feature of photosynthetic electron transport. Thus, on the one hand when bound by proteins, chloroplast-intrinsic metals are a prerequisite for photoautotrophic life, but on the other hand become toxic when present in their highly reactive, radical generating, free ionic forms. In consequence, transport, storage and cofactor-assembly of metal ions in plastids have to be tightly controlled and are crucial throughout plant growth and development. In the recent years, proteins for iron transport have been isolated from chloroplast envelope membranes. Here, we discuss their putative functions and impact on cellular metal homeostasis as well as photosynthetic performance and plant metabolism. We further consider the potential of proteomic analyses to identify new players in the field.
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Affiliation(s)
- Ana F. López-Millán
- Department of Pediatrics, Children’s Nutrition Research Center, Baylor College of Medicine, United States Department of Agriculture/Agricultural Research Service, HoustonTX, USA
| | - Daniela Duy
- Plastid Fatty Acid and Iron Transport – Plant Biochemistry and Physiology, Department Biology I, Ludwig-Maximilians-University of MunichMunich, Germany
| | - Katrin Philippar
- Plastid Fatty Acid and Iron Transport – Plant Biochemistry and Physiology, Department Biology I, Ludwig-Maximilians-University of MunichMunich, Germany
- *Correspondence: Katrin Philippar,
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21
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Pottosin I, Dobrovinskaya O. Ion Channels in Native Chloroplast Membranes: Challenges and Potential for Direct Patch-Clamp Studies. Front Physiol 2015; 6:396. [PMID: 26733887 PMCID: PMC4686732 DOI: 10.3389/fphys.2015.00396] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/04/2015] [Indexed: 11/29/2022] Open
Abstract
Photosynthesis without any doubt depends on the activity of the chloroplast ion channels. The thylakoid ion channels participate in the fine partitioning of the light-generated proton-motive force (p.m.f.). By regulating, therefore, luminal pH, they affect the linear electron flow and non-photochemical quenching. Stromal ion homeostasis and signaling, on the other hand, depend on the activity of both thylakoid and envelope ion channels. Experimentally, intact chloroplasts and swollen thylakoids were proven to be suitable for direct measurements of the ion channels activity via conventional patch-clamp technique; yet, such studies became infrequent, although their potential is far from being exhausted. In this paper we wish to summarize existing challenges for direct patch-clamping of native chloroplast membranes as well as present available results on the activity of thylakoid Cl− (ClC?) and divalent cation-permeable channels, along with their tentative roles in the p.m.f. partitioning, volume regulation, and stromal Ca2+ and Mg2+ dynamics. Patch-clamping of the intact envelope revealed both large-conductance porin-like channels, likely located in the outer envelope membrane and smaller conductance channels, more compatible with the inner envelope location. Possible equivalent model for the sandwich-like arrangement of the two envelope membranes within the patch electrode will be discussed, along with peculiar properties of the fast-activated cation channel in the context of the stromal pH control.
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Affiliation(s)
- Igor Pottosin
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima Colima, Mexico
| | - Oxana Dobrovinskaya
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima Colima, Mexico
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22
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Butler CA, Dashper SG, Khan HS, Zhang L, Reynolds EC. The interplay between iron, haem and manganese in Porphyromonas gingivalis. J Oral Biosci 2015. [DOI: 10.1016/j.job.2014.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Barnett JP, Scanlan DJ, Blindauer CA. Identification of major zinc-binding proteins from a marine cyanobacterium: insight into metal uptake in oligotrophic environments. Metallomics 2014; 6:1254-68. [DOI: 10.1039/c4mt00048j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The open ocean cyanobacteriumSynechococcussp. WH8102 thrives at extremely low zinc concentrations. Metalloproteomics experiments have identified an outer-membrane bound porin with zinc-binding ability that is upregulated at low zinc levels, suggesting a role for porins in highly efficient zinc uptake.
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24
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Checchetto V, Teardo E, Carraretto L, Formentin E, Bergantino E, Giacometti GM, Szabo I. Regulation of photosynthesis by ion channels in cyanobacteria and higher plants. Biophys Chem 2013; 182:51-7. [PMID: 23891570 DOI: 10.1016/j.bpc.2013.06.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/10/2013] [Accepted: 06/10/2013] [Indexed: 11/25/2022]
Abstract
Photosynthesis converts light energy into chemical energy, and supplies ATP and NADPH for CO2 fixation into carbohydrates and for the synthesis of several compounds which are essential for autotrophic growth. Oxygenic photosynthesis takes place in thylakoid membranes of chloroplasts and photosynthetic prokaryote cyanobacteria. An ancestral photoautotrophic prokaryote related to cyanobacteria has been proposed to give rise to chloroplasts of plants and algae through an endosymbiotic event. Indeed, photosynthetic complexes involved in the electron transport coupled to H(+) translocation and ATP synthesis are similar in higher plants and cyanobacteria. Furthermore, some of the protein and solute/ion conducting machineries also share common structure and function. Electrophysiological and biochemical evidence support the existence of ion channels in the thylakoid membrane in both types of organisms. By allowing specific ion fluxes across thylakoid membranes, ion channels have been hypothesized to either directly or indirectly regulate photosynthesis, by modulating the proton motive force. Recent molecular identification of some of the thylakoid-located channels allowed to obtain genetic proof in favor of such hypothesis. Furthermore, some ion channels of the envelope membrane in chloroplasts have also been shown to impact on this light-driven process. Here we give an overview of thylakoid/chloroplast located ion channels of higher plants and of cyanobacterium Synechocystis sp. PCC 6803. We focus on channels shown to be implicated in the regulation of photosynthesis and discuss the possible mechanisms of action.
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Affiliation(s)
- Vanessa Checchetto
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
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25
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Abstract
Plasmodium and Toxoplasma are genera of apicomplexan parasites that infect millions of people each year. The former causes malaria, and the latter causes neurotropic infections associated with a weakened or developing immune system. These parasites harbor a peculiar organelle, the apicoplast. The apicoplast is the product of an ancient endosymbiosis between a heterotrophic and a photosynthetic protist. We explore the cellular and molecular mechanisms that enabled a stable union of two previously independent organisms. These include the exchange of metabolites, transfer of genes, transport of proteins, and overall coordination of biogenesis and proliferation. These mechanisms are still active today and can be exploited to treat parasite infection. They were shaped by the dramatic changes that occurred in the evolution of the phylum Apicomplexa--including the gain and loss of photosynthesis, adaptation to symbiosis and parasitism, and the explosion of animal diversity-that ultimately provided an aquatic alga access to every biotope on this planet.
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Affiliation(s)
- Giel G van Dooren
- Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia;
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Solti A, Kovács K, Basa B, Vértes A, Sárvári E, Fodor F. Uptake and incorporation of iron in sugar beet chloroplasts. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2012; 52:91-7. [PMID: 22305071 DOI: 10.1016/j.plaphy.2011.11.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 11/29/2011] [Indexed: 05/24/2023]
Abstract
Chloroplasts contain 80-90% of iron taken up by plant cells. Though some iron transport-related envelope proteins were identified recently, the mechanism of iron uptake into chloroplasts remained unresolved. To shed more light on the process of chloroplast iron uptake, trials were performed with isolated intact chloroplasts of sugar beet (Beta vulgaris). Iron uptake was followed by measuring the iron content of chloroplasts in the form of ferrous-bathophenantroline-disulphonate complex after solubilising the chloroplasts in reducing environment. Ferric citrate was preferred to ferrous citrate as substrate for chloroplasts. Strong dependency of ferric citrate uptake on photosynthetic electron transport activity suggests that ferric chelate reductase uses NADPH, and is localised in the inner envelope membrane. The K(m) for iron uptake from ferric-citrate pool was 14.65 ± 3.13 μM Fe((III))-citrate. The relatively fast incorporation of (57)Fe isotope into Fe-S clusters/heme, detected by Mössbauer spectroscopy, showed the efficiency of the biosynthetic machinery of these cofactors in isolated chloroplasts. The negative correlation between the chloroplast iron concentration and the rate of iron uptake refers to a strong feedback regulation of the uptake.
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Affiliation(s)
- Adám Solti
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Eötvös Loránd University, Pázmány P. lane 1/C, Budapest 1117, Hungary
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Pudelski B, Schock A, Hoth S, Radchuk R, Weber H, Hofmann J, Sonnewald U, Soll J, Philippar K. The plastid outer envelope protein OEP16 affects metabolic fluxes during ABA-controlled seed development and germination. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1919-36. [PMID: 22155670 PMCID: PMC3295387 DOI: 10.1093/jxb/err375] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 10/15/2011] [Accepted: 10/21/2011] [Indexed: 05/20/2023]
Abstract
Previously, the OEP16.1 channel pore in the outer envelope membrane of mature pea (Pisum sativum) chloroplasts in vitro has been characterized to be selective for amino acids. Isolation of OEP16.2, a second OEP16 isoform from pea, in the current study allowed membrane localization and gene expression of OEP16 to be followed throughout seed development and germination of Arabidopsis thaliana and P. sativum. Thereby it can be shown on the transcript and protein level that the isoforms OEP16.1 and OEP16.2 in both plant species are alternating: whereas OEP16.1 is prominent in early embryo development and first leaves of the growing plantlet, OEP16.2 dominates in late seed development stages, which are associated with dormancy and desiccation, as well as early germination events. Further, OEP16.2 expression in seeds is under control of the phytohormone abscisic acid (ABA), leading to an ABA-hypersensitive phenotype of germinating oep16 knockout mutants. In consequence, the loss of OEP16 causes metabolic imbalance, in particular that of amino acids during seed development and early germination. It is thus concluded that in vivo OEP16 most probably functions in shuttling amino acids across the outer envelope of seed plastids.
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Affiliation(s)
- Birgit Pudelski
- Biochemie und Physiologie der Pflanzen, Department Biologie I, Botanik, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
- Munich Centre for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, D-81377 München, Germany
| | - Annette Schock
- Biochemie und Physiologie der Pflanzen, Department Biologie I, Botanik, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
- Munich Centre for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, D-81377 München, Germany
| | - Stefan Hoth
- Molekulare Pflanzenphysiologie, Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany
- Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität Hamburg, Ohnhorststrabe 18, D-22609 Hamburg, Germany
| | - Ruslana Radchuk
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany
| | - Hans Weber
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany
| | - Jörg Hofmann
- Biochemie, Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany
| | - Uwe Sonnewald
- Biochemie, Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany
| | - Jürgen Soll
- Biochemie und Physiologie der Pflanzen, Department Biologie I, Botanik, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
- Munich Centre for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, D-81377 München, Germany
| | - Katrin Philippar
- Biochemie und Physiologie der Pflanzen, Department Biologie I, Botanik, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
- Munich Centre for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, D-81377 München, Germany
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Arabidopsis calcium-binding mitochondrial carrier proteins as potential facilitators of mitochondrial ATP-import and plastid SAM-import. FEBS Lett 2011; 585:3935-40. [PMID: 22062157 DOI: 10.1016/j.febslet.2011.10.039] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 10/06/2011] [Accepted: 10/23/2011] [Indexed: 11/20/2022]
Abstract
Chloroplasts and mitochondria are central to crucial cellular processes in plants and contribute to a whole range of metabolic pathways. The use of calcium ions as a secondary messenger in and around organelles is increasingly appreciated as an important mediator of plant cell signaling, enabling plants to develop or to acclimatize to changing environmental conditions. Here, we have studied the four calcium-dependent mitochondrial carriers that are encoded in the Arabidopsis genome. An unknown substrate carrier, which was previously found to localize to chloroplasts, is proposed to present a calcium-dependent S-adenosyl methionine carrier. For three predicted ATP/phosphate carriers, we present experimental evidence that they can function as mitochondrial ATP-importers.
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Inoue K. Emerging roles of the chloroplast outer envelope membrane. TRENDS IN PLANT SCIENCE 2011; 16:550-7. [PMID: 21775189 DOI: 10.1016/j.tplants.2011.06.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 06/11/2011] [Accepted: 06/15/2011] [Indexed: 05/25/2023]
Abstract
The chloroplast is essential for the viability of plants. It is enclosed by a double-membrane envelope that originated from the outer and plasma membranes of a cyanobacterial endosymbiont. Chloroplast biogenesis depends on binary fission and import of nuclear-encoded proteins. Our understanding of the mechanisms and evolutionary origins of these processes has been greatly advanced by recent genetic and biochemical studies on envelope-localized multiprotein machines. Furthermore, the latest studies on outer envelope proteins have provided molecular insights into organelle movement and membrane lipid remodeling, activities that are vital for plant survival under diverse environmental conditions. Ongoing and future research on the chloroplast outer envelope should add to our knowledge of organelle biology and the evolution of eukaryotic cells.
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Affiliation(s)
- Kentaro Inoue
- Department of Plant Sciences, University of California, Davis, CA 95616, USA.
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Bacterial outer membrane channel for divalent metal ion acquisition. Proc Natl Acad Sci U S A 2011; 108:15390-5. [PMID: 21880957 DOI: 10.1073/pnas.1110137108] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The prevailing model of bacterial membrane function predicts that the outer membrane is permeable to most small solutes because of pores with limited selectivity based primarily on size. Here, we identified mnoP in the Gram-negative bacterium Bradyrhizobium japonicum as a gene coregulated with the inner membrane Mn(2+) transporter gene mntH. MnoP is an outer membrane protein expressed specifically under manganese limitation. MnoP acts as a channel to facilitate the tranlocation of Mn(2+), but not Co(2+) or Cu(2+), into reconstituted proteoliposomes. An mnoP mutant is defective in high-affinity Mn(2+) transport into cells and has a severe growth phenotype under manganese limitation. We suggest that the outer membrane is a barrier to divalent metal ions that requires a selective channel to meet the nutritional needs of the cell.
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Andrade IDS, Vianez-Júnior JL, Goulart CL, Homblé F, Ruysschaert JM, Almeida von Krüger WM, Bisch PM, de Souza W, Mohana-Borges R, Motta MCM. Characterization of a porin channel in the endosymbiont of the trypanosomatid protozoan Crithidia deanei. MICROBIOLOGY-SGM 2011; 157:2818-2830. [PMID: 21757490 DOI: 10.1099/mic.0.049247-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Crithidia deanei is a trypanosomatid protozoan that harbours a symbiotic bacterium. The partners maintain a mutualistic relationship, thus constituting an excellent model for studying metabolic exchanges between the host and the symbiont, the origin of organelles and cellular evolution. According to molecular analysis, symbionts of different trypanosomatid species share high identity and descend from a common ancestor, a β-proteobacterium of the genus Bordetella. The endosymbiont is surrounded by two membranes, like Gram-negative bacteria, but its envelope presents special features, since phosphatidylcholine is a major membrane component and the peptidoglycan layer is highly reduced, as described in other obligate intracellular bacteria. Like the process that generated mitochondria and plastids, the endosymbiosis in trypanosomatids depends on pathways that facilitate the intensive metabolic exchanges between the bacterium and the host protozoan. A search of the annotated symbiont genome database identified one sequence with identity to porin-encoding genes of the genus Bordetella. Considering that the symbiont outer membrane has a great accessibility to cytoplasm host factors, it was important to characterize this single porin-like protein using biochemical, molecular, computational and ultrastructural approaches. Antiserum against the recombinant porin-like molecule revealed that it is mainly located in the symbiont envelope. Secondary structure analysis and comparative modelling predicted the protein 3D structure as an 18-domain β-barrel, which is consistent with porin channels. Electrophysiological measurements showed that the porin displays a slight preference for cations over anions. Taken together, the data presented herein suggest that the C. deanei endosymbiont porin is phylogenetically and structurally similar to those described in Gram-negative bacteria, representing a diffusion channel that might contribute to the exchange of nutrients and metabolic precursors between the symbiont and its host cell.
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Affiliation(s)
- Iamara da Silva Andrade
- Instituto Nacional de Ciência e Tecnologia em Bioimagens e Biologia Estrutural, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, Brazil.,Laboratório de Genômica Estrutural, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil.,Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil
| | - João Lídio Vianez-Júnior
- Laboratório de Física Biológica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil
| | - Carolina Lage Goulart
- Laboratoire de Structure et Fonction des Membranes Biologiques (SFMB), Université Libre de Bruxelles, Campus Plaine (CP 206/2), B-1050 Bruxelles, Belgium.,Unidade Multidisciplinar de Genômica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Bioimagens e Biologia Estrutural, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, Brazil
| | - Fabrice Homblé
- Laboratoire de Structure et Fonction des Membranes Biologiques (SFMB), Université Libre de Bruxelles, Campus Plaine (CP 206/2), B-1050 Bruxelles, Belgium
| | - Jean-Marie Ruysschaert
- Laboratoire de Structure et Fonction des Membranes Biologiques (SFMB), Université Libre de Bruxelles, Campus Plaine (CP 206/2), B-1050 Bruxelles, Belgium
| | - Wanda Maria Almeida von Krüger
- Unidade Multidisciplinar de Genômica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Bioimagens e Biologia Estrutural, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, Brazil
| | - Paulo Mascarello Bisch
- Unidade Multidisciplinar de Genômica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil.,Laboratório de Física Biológica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Bioimagens e Biologia Estrutural, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, Brazil
| | - Wanderley de Souza
- Instituto Nacional de Metrologia, Normalização e Qualidade Industrial, Inmetro, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Bioimagens e Biologia Estrutural, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, Brazil.,Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil
| | - Ronaldo Mohana-Borges
- Instituto Nacional de Ciência e Tecnologia em Bioimagens e Biologia Estrutural, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, Brazil.,Laboratório de Genômica Estrutural, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil
| | - Maria Cristina Machado Motta
- Instituto Nacional de Ciência e Tecnologia em Bioimagens e Biologia Estrutural, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, Brazil.,Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil
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32
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Spetea C, Schoefs B. Solute transporters in plant thylakoid membranes: Key players during photosynthesis and light stress. Commun Integr Biol 2011; 3:122-9. [PMID: 20585503 DOI: 10.4161/cib.3.2.10909] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Accepted: 12/09/2009] [Indexed: 11/19/2022] Open
Abstract
Plants utilize sunlight to drive photosynthetic energy conversion in the chloroplast thylakoid membrane. Here are located four major photosynthetic complexes, about which we have great knowledge in terms of structure and function. However, much less we know about auxiliary proteins, such as transporters, ensuring an optimum function and turnover of these complexes. The most prominent thylakoid transporter is the proton-translocating ATP-synthase. Recently, four additional transporters have been identified in the thylakoid membrane of Arabidopsis thaliana, namely one copper-transporting P-ATPase, one chloride channel, one phosphate transporter, and one ATP/ADP carrier. Here, we review the current knowledge on the function and physiological role of these transporters during photosynthesis and light stress in plants. Subsequently, we make a survey on the outlook of thylakoid activities awaiting identification of responsible proteins. Such knowledge is necessary to understand the thylakoid network of transporters, and to design strategies for bioengineering crop plants in the future.
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Breuers FKH, Bräutigam A, Weber APM. The Plastid Outer Envelope - A Highly Dynamic Interface between Plastid and Cytoplasm. FRONTIERS IN PLANT SCIENCE 2011; 2:97. [PMID: 22629266 PMCID: PMC3355566 DOI: 10.3389/fpls.2011.00097] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 11/29/2011] [Indexed: 05/09/2023]
Abstract
Plastids are the defining organelles of all photosynthetic eukaryotes. They are the site of photosynthesis and of a large number of other essential metabolic pathways, such as fatty acid and amino acid biosyntheses, sulfur and nitrogen assimilation, and aromatic and terpenoid compound production, to mention only a few examples. The metabolism of plastids is heavily intertwined and connected with that of the surrounding cytosol, thus causing massive traffic of metabolic precursors, intermediates, and products. Two layers of biological membranes that are called the inner (IE) and the outer (OE) plastid envelope membranes bound the plastids of Archaeplastida. While the IE is generally accepted as the osmo-regulatory barrier between cytosol and stroma, the OE was considered to represent an unspecific molecular sieve, permeable for molecules of up to 10 kDa. However, after the discovery of small substrate specific pores in the OE, this view has come under scrutiny. In addition to controlling metabolic fluxes between plastid and cytosol, the OE is also crucial for protein import into the chloroplast. It contains the receptors and translocation channel of the TOC complex that is required for the canonical post-translational import of nuclear-encoded, plastid-targeted proteins. Further, the OE is a metabolically active compartment of the chloroplast, being involved in, e.g., fatty acid metabolism and membrane lipid production. Also, recent findings hint on the OE as a defense platform against several biotic and abiotic stress conditions, such as cold acclimation, freezing tolerance, and phosphate deprivation. Moreover, dynamic non-covalent interactions between the OE and the endomembrane system are thought to play important roles in lipid and non-canonical protein trafficking between plastid and endoplasmic reticulum. While proteomics and bioinformatics has provided us with comprehensive but still incomplete information on proteins localized in the plastid IE, the stroma, and the thylakoids, our knowledge of the protein composition of the plastid OE is far from complete. In this article, we report on the recent progress in discovering novel OE proteins to draw a conclusive picture of the OE. A "parts list" of the plastid OE will be presented, using data generated by proteomics of plastids isolated from various plant sources.
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Affiliation(s)
| | - Andrea Bräutigam
- Institut für Biochemie der Pflanzen, Heinrich-Heine Universität DüsseldorfDüsseldorf, Germany
| | - Andreas P. M. Weber
- Institut für Biochemie der Pflanzen, Heinrich-Heine Universität DüsseldorfDüsseldorf, Germany
- *Correspondence: Andreas P. M. Weber, Institut für Biochemie der Pflanzen, Heinrich-Heine Universität Düsseldorf, Universitätstrasse 1, D-40225 Düsseldorf, Germany. e-mail:
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Weber APM, Linka N. Connecting the plastid: transporters of the plastid envelope and their role in linking plastidial with cytosolic metabolism. ANNUAL REVIEW OF PLANT BIOLOGY 2011; 62:53-77. [PMID: 21526967 DOI: 10.1146/annurev-arplant-042110-103903] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Plastids have a multitude of functions in eukaryotic cells, ranging from photosynthesis to storage, and a role in essential biosynthetic pathways. All plastids are of either primary or higher-order endosymbiotic origin. That is, either a photosynthetic cyanobacterium was integrated into a mitochondriate eukaryotic host cell (primary endosymbiosis) or a plastid-bearing eukaryotic cell merged with another eukaryotic cell (secondary or higher-order endosymbioses), thereby passing on the plastid between various eukaryotic lineages. For all of these endosymbioses to become functional, it was essential to establish metabolic connections between organelle and host cell. Here, we review the present understanding of metabolite exchange between plastids and the surrounding cytosol in the context of the endosymbiotic origin of plastids in various eukaryotic lineages. We show that only a small number of transporters that can be traced down to the primary endosymbiotic event are conserved between plastids of diverse origins.
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Affiliation(s)
- Andreas P M Weber
- Institute of Plant Biochemistry, Heinrich-Heine Universität Düsseldorf, 40225 Düsseldorf, Germany.
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35
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Facchinelli F, Weber APM. The metabolite transporters of the plastid envelope: an update. FRONTIERS IN PLANT SCIENCE 2011; 2:50. [PMID: 22645538 PMCID: PMC3355759 DOI: 10.3389/fpls.2011.00050] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Accepted: 08/23/2011] [Indexed: 05/19/2023]
Abstract
The engulfment of a photoautotrophic cyanobacterium by a primitive mitochondria-bearing eukaryote traces back to more than 1.2 billion years ago. This single endosymbiotic event not only provided the early petroalgae with the metabolic capacity to perform oxygenic photosynthesis, but also introduced a plethora of other metabolic routes ranging from fatty acids and amino acids biosynthesis, nitrogen and sulfur assimilation to secondary compounds synthesis. This implicated the integration and coordination of the newly acquired metabolic entity with the host metabolism. The interface between the host cytosol and the plastidic stroma became of crucial importance in sorting precursors and products between the plastid and other cellular compartments. The plastid envelope membranes fulfill different tasks: they perform important metabolic functions, as they are involved in the synthesis of carotenoids, chlorophylls, and galactolipids. In addition, since most genes of cyanobacterial origin have been transferred to the nucleus, plastidial proteins encoded by nuclear genes are post-translationally transported across the envelopes through the TIC-TOC import machinery. Most importantly, chloroplasts supply the photoautotrophic cell with photosynthates in form of reduced carbon. The innermost bilayer of the plastidic envelope represents the permeability barrier for the metabolites involved in the carbon cycle and is literally stuffed with transporter proteins facilitating their transfer. The intracellular metabolite transporters consist of polytopic proteins containing membrane spans usually in the number of four or more α-helices. Phylogenetic analyses revealed that connecting the plastid with the host metabolism was mainly a process driven by the host cell. In Arabidopsis, 58% of the metabolite transporters are of host origin, whereas only 12% are attributable to the cyanobacterial endosymbiont. This review focuses on the metabolite transporters of the inner envelope membrane of plastids, in particular the electrochemical potential-driven class of transporters. Recent advances in elucidating the plastidial complement of metabolite transporters are provided, with an update on phylogenetic relationship of selected proteins.
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Affiliation(s)
- Fabio Facchinelli
- Institut für Biochemie der Pflanzen, Heinrich-Heine Universität Düsseldorf Düsseldorf, Germany
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36
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Radchuk R, Conrad U, Saalbach I, Giersberg M, Emery RJN, Küster H, Nunes-Nesi A, Fernie AR, Weschke W, Weber H. Abscisic acid deficiency of developing pea embryos achieved by immunomodulation attenuates developmental phase transition and storage metabolism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 64:715-30. [PMID: 21105920 DOI: 10.1111/j.1365-313x.2010.04376.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The transition of pea embryos from pre-storage to maturation is partially controlled by abscisic acid (ABA). Immunomodulation in pea embryos specifically reduces free ABA levels during transition stages. Such seeds are, therefore, suitable models for studying ABA deficiency by global transcript and metabolite analysis. Compared with the wild type, anti-ABA seeds are smaller, contain fewer globulins and show lower dry matter accumulation and delayed differentiation. Free sugars are decreased, indicating lower uptake and/or elevated mobilisation. Lower levels of trans-zeatins suggest that ABA reduction influences rates of cytokinin synthesis and/or its level of accumulation. Abscisic acid deficiency leads to a general downregulation of gene expression related to transcription and translation. At the transcriptional level, anti-ABA embryos reveal a wide-range repression of carbohydrate oxidation, downregulated sucrose mobilisation, glycolysis and the tricarboxylic acid cycle/Krebs cycle (TCA cycle). Genes related to starch, amino acid and storage protein biosynthesis are downregulated, indicating a general decrease in metabolic fluxes. We conclude that during embryo differentiation ABA triggers broad upregulation of gene activity and genetic reprogramming, involving regulated protein degradation via the ubiquitin/proteasome system. Abscisic acid deficiency affects gene expression associated with transport processes and stimulation of membrane energisation. Our study identified mediators and downstream signalling elements of ABA during embryo differentiation, such as the transcription factor FUSCA3, SnRK1 kinase and Ca(2+) signalling processes. This suggests that ABA interacts with SnRK1 complexes, thus connecting SnRK1, sugar and stress signalling with ABA. Certain protein kinases/phosphatases known to negatively respond to ABA are upregulated in the modulated line, whilst those which respond positively are downregulated, pointing to a highly coordinated response of the gene network to ABA levels.
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Affiliation(s)
- Ruslana Radchuk
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), D-06466 Gatersleben, Germany
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37
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Tegeder M, Rentsch D. Uptake and partitioning of amino acids and peptides. MOLECULAR PLANT 2010; 3:997-1011. [PMID: 21081651 DOI: 10.1093/mp/ssq047] [Citation(s) in RCA: 176] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Plant growth, productivity, and seed yield depend on the efficient uptake, metabolism, and allocation of nutrients. Nitrogen is an essential macronutrient needed in high amounts. Plants have evolved efficient and selective transport systems for nitrogen uptake and transport within the plant to sustain development, growth, and finally reproduction. This review summarizes current knowledge on membrane proteins involved in transport of amino acids and peptides. A special emphasis was put on their function in planta. We focus on uptake of the organic nitrogen by the root, source-sink partitioning, and import into floral tissues and seeds.
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Affiliation(s)
- Mechthild Tegeder
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA.
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38
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Pudelski B, Kraus S, Soll J, Philippar K. The plant PRAT proteins - preprotein and amino acid transport in mitochondria and chloroplasts. PLANT BIOLOGY (STUTTGART, GERMANY) 2010; 12 Suppl 1:42-55. [PMID: 20712620 DOI: 10.1111/j.1438-8677.2010.00357.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The membrane proteins of the plant preprotein and amino acid transporter (PRAT) superfamily all share common structural elements, such as four membrane-spanning alpha-helices. Interestingly they display diverse localisation to outer and inner membranes of chloroplasts and mitochondria. Furthermore, they fulfil different functions in preprotein translocation as well as amino acid transport across these membranes. This review summarises current knowledge on precursor protein import and amino acid transport in plastids and mitochondria and provides an overview of the distinct tasks and features of members of the PRAT superfamily in the model plant Arabidopsis thaliana.
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Affiliation(s)
- B Pudelski
- Biochemie und Physiologie der Pflanzen, Department Biologie I, Botanik, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
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Nowack ECM, Vogel H, Groth M, Grossman AR, Melkonian M, Glockner G. Endosymbiotic Gene Transfer and Transcriptional Regulation of Transferred Genes in Paulinella chromatophora. Mol Biol Evol 2010; 28:407-22. [DOI: 10.1093/molbev/msq209] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Peixoto PM, Ryu SY, Kinnally KW. Mitochondrial ion channels as therapeutic targets. FEBS Lett 2010; 584:2142-52. [PMID: 20178788 PMCID: PMC2872129 DOI: 10.1016/j.febslet.2010.02.046] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 02/12/2010] [Accepted: 02/16/2010] [Indexed: 12/31/2022]
Abstract
The study of mitochondrial ion channels changed our perception of these double-wrapped organelles from being just the power house of a cell to the guardian of a cell's fate. Mitochondria communicate with the cell through these special channels. Most of the time, the message is encoded by ion flow across the mitochondrial outer and inner membranes. Potassium, sodium, calcium, protons, nucleotides, and proteins traverse the mitochondrial membranes in an exquisitely regulated manner to control a myriad of processes, from respiration and mitochondrial morphology to cell proliferation and cell death. This review is an update on both well established and putative mitochondrial channels regarding their composition, function, regulation, and therapeutic potential.
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Affiliation(s)
| | - Shin-Young Ryu
- New York University College of Dentistry, New York, NY, 10002
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41
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Remmert M, Biegert A, Linke D, Lupas AN, Söding J. Evolution of outer membrane beta-barrels from an ancestral beta beta hairpin. Mol Biol Evol 2010; 27:1348-58. [PMID: 20106904 DOI: 10.1093/molbev/msq017] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Outer membrane beta-barrels (OMBBs) are the major class of outer membrane proteins from Gram-negative bacteria, mitochondria, and plastids. Their transmembrane domains consist of 8-24 beta-strands forming a closed, barrel-shaped beta-sheet around a central pore. Despite their obvious structural regularity, evidence for an origin by duplication or for a common ancestry has not been found. We use three complementary approaches to show that all OMBBs from Gram-negative bacteria evolved from a single, ancestral beta beta hairpin. First, we link almost all families of known single-chain bacterial OMBBs with each other through transitive profile searches. Second, we identify a clear repeat signature in the sequences of many OMBBs in which the repeating sequence unit coincides with the structural beta beta hairpin repeat. Third, we show that the observed sequence similarity between OMBB hairpins cannot be explained by structural or membrane constraints on their sequences. The third approach addresses a longstanding problem in protein evolution: how to distinguish between a very remotely homologous relationship and the opposing scenario of "sequence convergence." The origin of a diverse group of proteins from a single hairpin module supports the hypothesis that, around the time of transition from the RNA to the protein world, proteins arose by amplification and recombination of short peptide modules that had previously evolved as cofactors of RNAs.
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Affiliation(s)
- M Remmert
- Department of Biochemistry, Gene Center Munich and Center for Integrated Protein Science (CIPSM), Ludwig-Maximilians-Universtät München, Munich, Germany
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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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Liguori L, Blesneac I, Madern D, Vivaudou M, Lenormand JL. Single-step production of functional OEP24 proteoliposomes. Protein Expr Purif 2010; 69:106-11. [DOI: 10.1016/j.pep.2009.07.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 07/07/2009] [Accepted: 07/07/2009] [Indexed: 10/20/2022]
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Bodył A, Mackiewicz P, Stiller JW. Early steps in plastid evolution: current ideas and controversies. Bioessays 2009; 31:1219-32. [DOI: 10.1002/bies.200900073] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gross J, Bhattacharya D. Mitochondrial and plastid evolution in eukaryotes: an outsiders' perspective. Nat Rev Genet 2009; 10:495-505. [PMID: 19506574 DOI: 10.1038/nrg2610] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The eukaryotic organelles mitochondrion and plastid originated from eubacterial endosymbionts. Here we propose that, in both cases, prokaryote-to-organelle conversion was driven by the internalization of host-encoded factors progressing from the outer membrane of the endosymbionts towards the intermembrane space, inner membrane and finally the organelle interior. This was made possible by an outside-to-inside establishment in the endosymbionts of host-controlled protein-sorting components, which enabled the gradual integration of organelle functions into the nuclear genome. Such a convergent trajectory for mitochondrion and plastid establishment suggests a novel paradigm for organelle evolution that affects theories of eukaryogenesis.
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Affiliation(s)
- Jeferson Gross
- Department of Biology, Roy J. Carver Center for Comparative Genomics, University of Iowa, 446 Biology Building, Iowa City, Iowa 52242, USA
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Nowack EC, Melkonian M, Glöckner G. Chromatophore Genome Sequence of Paulinella Sheds Light on Acquisition of Photosynthesis by Eukaryotes. Curr Biol 2008; 18:410-8. [DOI: 10.1016/j.cub.2008.02.051] [Citation(s) in RCA: 168] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 02/14/2008] [Accepted: 02/15/2008] [Indexed: 01/25/2023]
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