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Özdemir M, Dennerlein S. The TOM complex from an evolutionary perspective and the functions of TOMM70. Biol Chem 2024; 0:hsz-2024-0043. [PMID: 39092472 DOI: 10.1515/hsz-2024-0043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 07/17/2024] [Indexed: 08/04/2024]
Abstract
In humans, up to 1,500 mitochondrial precursor proteins are synthesized at cytosolic ribosomes and must be imported into the organelle. This is not only essential for mitochondrial but also for many cytosolic functions. The majority of mitochondrial precursor proteins are imported over the translocase of the outer membrane (TOM). In recent years, high-resolution structure analyses from different organisms shed light on the composition and arrangement of the TOM complex. Although significant similarities have been found, differences were also observed, which have been favored during evolution and could reflect the manifold functions of TOM with cellular signaling and its response to altered metabolic situations. A key component within these regulatory mechanisms is TOMM70, which is involved in protein import, forms contacts to the ER and the nucleus, but is also involved in cellular defense mechanisms during infections.
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Affiliation(s)
- Metin Özdemir
- Institute for Cellular Biochemistry, University Medical Center Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Sven Dennerlein
- Institute for Cellular Biochemistry, University Medical Center Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany
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2
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Vacuolal and Peroxisomal Calcium Ion Transporters in Yeasts and Fungi: Key Role in the Translocation of Intermediates in the Biosynthesis of Fungal Metabolites. Genes (Basel) 2022; 13:genes13081450. [PMID: 36011361 PMCID: PMC9407949 DOI: 10.3390/genes13081450] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 11/25/2022] Open
Abstract
Highlights The intracellular calcium content plays a key role in the expression of genes involved in the biosynthesis and secretion of fungal metabolites. The cytosolic calcium concentration in fungi is maintained by influx through the cell membrane and by release from store organelles. Some MSF transporters, e.g., PenV of Penicillium chrysogenum and CefP of Acremonium chrysogenum belong to the TRP calcium ion channels. A few of the numerous calcium ion transporters existing in organelles of different filamentous fungi have been characterized at the functional and subcellular localization levels. The cytosolic calcium signal seems to be transduced by the calcitonin/calcineurin cascade controlling the expression of many fungal genes.
Abstract The intracellular calcium content in fungal cells is influenced by a large number of environmental and nutritional factors. Sharp changes in the cytosolic calcium level act as signals that are decoded by the cell gene expression machinery, resulting in several physiological responses, including differentiation and secondary metabolites biosynthesis. Expression of the three penicillin biosynthetic genes is regulated by calcium ions, but there is still little information on the role of this ion in the translocation of penicillin intermediates between different subcellular compartments. Using advanced information on the transport of calcium in organelles in yeast as a model, this article reviews the recent progress on the transport of calcium in vacuoles and peroxisomes and its relation to the translocation of biosynthetic intermediates in filamentous fungi. The Penicillium chrysogenum PenV vacuole transporter and the Acremonium chrysogenum CefP peroxisomal transporter belong to the transient receptor potential (TRP) class CSC of calcium ion channels. The PenV transporter plays an important role in providing precursors for the biosynthesis of the tripeptide δ-(-α-aminoadipyl-L-cysteinyl-D-valine), the first intermediate of penicillin biosynthesis in P. chrysogenum. Similarly, CefP exerts a key function in the conversion of isopenicillin N to penicillin N in peroxisomes of A. chrysogenum. These TRP transporters are different from other TRP ion channels of Giberella zeae that belong to the Yvc1 class of yeast TRPs. Recent advances in filamentous fungi indicate that the cytosolic calcium concentration signal is connected to the calcitonin/calcineurin signal transduction cascade that controls the expression of genes involved in the subcellular translocation of intermediates during fungal metabolite biosynthesis. These advances open new possibilities to enhance the expression of important biosynthetic genes in fungi.
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He J, Rössner N, Hoang MTT, Alejandro S, Peiter E. Transport, functions, and interaction of calcium and manganese in plant organellar compartments. PLANT PHYSIOLOGY 2021; 187:1940-1972. [PMID: 35235665 PMCID: PMC8890496 DOI: 10.1093/plphys/kiab122] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/02/2021] [Indexed: 05/05/2023]
Abstract
Calcium (Ca2+) and manganese (Mn2+) are essential elements for plants and have similar ionic radii and binding coordination. They are assigned specific functions within organelles, but share many transport mechanisms to cross organellar membranes. Despite their points of interaction, those elements are usually investigated and reviewed separately. This review takes them out of this isolation. It highlights our current mechanistic understanding and points to open questions of their functions, their transport, and their interplay in the endoplasmic reticulum (ER), vesicular compartments (Golgi apparatus, trans-Golgi network, pre-vacuolar compartment), vacuoles, chloroplasts, mitochondria, and peroxisomes. Complex processes demanding these cations, such as Mn2+-dependent glycosylation or systemic Ca2+ signaling, are covered in some detail if they have not been reviewed recently or if recent findings add to current models. The function of Ca2+ as signaling agent released from organelles into the cytosol and within the organelles themselves is a recurrent theme of this review, again keeping the interference by Mn2+ in mind. The involvement of organellar channels [e.g. glutamate receptor-likes (GLR), cyclic nucleotide-gated channels (CNGC), mitochondrial conductivity units (MCU), and two-pore channel1 (TPC1)], transporters (e.g. natural resistance-associated macrophage proteins (NRAMP), Ca2+ exchangers (CAX), metal tolerance proteins (MTP), and bivalent cation transporters (BICAT)], and pumps [autoinhibited Ca2+-ATPases (ACA) and ER Ca2+-ATPases (ECA)] in the import and export of organellar Ca2+ and Mn2+ is scrutinized, whereby current controversial issues are pointed out. Mechanisms in animals and yeast are taken into account where they may provide a blueprint for processes in plants, in particular, with respect to tunable molecular mechanisms of Ca2+ versus Mn2+ selectivity.
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Affiliation(s)
- Jie He
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Nico Rössner
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Minh T T Hoang
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Santiago Alejandro
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Edgar Peiter
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
- Author for communication:
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4
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Pirayesh N, Giridhar M, Ben Khedher A, Vothknecht UC, Chigri F. Organellar calcium signaling in plants: An update. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:118948. [PMID: 33421535 DOI: 10.1016/j.bbamcr.2021.118948] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/13/2022]
Abstract
Calcium ion (Ca2+) is a versatile signaling transducer in all eukaryotic organisms. In plants, intracellular changes in free Ca2+ levels act as regulators in many growth and developmental processes. Ca2+ also mediates the cellular responses to environmental stimuli and thus plays an important role in providing stress tolerance to plants. Ca2+ signals are decoded by a tool kit of various families of Ca2+-binding proteins and their downstream targets, which mediate the transformation of the Ca2+ signal into appropriate cellular response. Early interest and research on Ca2+ signaling focused on its function in the cytosol, however it has become evident that this important regulatory pathway also exists in organelles such as nucleus, chloroplast, mitochondria, peroxisomes and the endomembrane system. In this review, we give an overview on the knowledge about organellar Ca2+ signaling with a focus on recent advances and developments.
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Affiliation(s)
- Niloufar Pirayesh
- Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
| | - Maya Giridhar
- Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
| | - Ahlem Ben Khedher
- Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
| | - Ute C Vothknecht
- Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany.
| | - Fatima Chigri
- Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany.
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Fraser MS, Dauphinee AN, Gunawardena AHLAN. Determining the effect of calcium on cell death rate and perforation formation during leaf development in the novel model system, the lace plant (Aponogeton madagascariensis). J Microsc 2019; 278:132-144. [PMID: 31875955 DOI: 10.1111/jmi.12859] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 12/30/2022]
Abstract
Programmed cell death (PCD) is the destruction of unwanted cells through an intracellularly mediated process. Perforation formation in the lace plant (Aponogeton madagascariensis) provides an excellent model for studying developmentally regulated PCD. Ca2+ fluxes have previously been identified as important signals for PCD in plants and mammals. The fundamental goal of this project was to determine the influence of Ca2+ on the rate of cell death and perforation formation during leaf development in the lace plant. This was investigated using the application of various known calcium modulators including lanthanum III chloride (LaCl3 ), ruthenium red and calcium ionophore A23187. Detached lace plant leaves at an early stage of development were treated with these modulators in both short- and long-term exposure assays and analysed using live cell imaging. Results from this study indicate that calcium plays a vital role in developmentally regulated PCD in the lace plant as application of the modulators significantly altered the rate of cell death and perforation formation during leaf development. In conclusion, this study exemplifies the suitability of the lace plant for live cell imaging and detached leaf experiments to study cell death and provides insight into the importance of Ca2+ in developmentally regulated PCD in planta.
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Affiliation(s)
| | - Adrian N Dauphinee
- Department of Biology, Dalhousie University, Halifax, Canada.,Current address: Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
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TOM70 Sustains Cell Bioenergetics by Promoting IP3R3-Mediated ER to Mitochondria Ca 2+ Transfer. Curr Biol 2018; 28:369-382.e6. [PMID: 29395920 DOI: 10.1016/j.cub.2017.12.047] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 11/22/2017] [Accepted: 12/20/2017] [Indexed: 01/09/2023]
Abstract
The mitochondrial translocase of the outer membrane (TOM) is a protein complex that is essential for the post-translational import of nuclear-encoded mitochondrial proteins. Among its subunits, TOM70 and TOM20 are only transiently associated with the core complex, suggesting their possible additional roles within the outer mitochondrial membrane (OMM). Here, by using different mammalian cell lines, we demonstrate that TOM70, but not TOM20, clusters in distinct OMM foci, frequently overlapping with sites in which the endoplasmic reticulum (ER) contacts mitochondria. Functionally, TOM70 depletion specifically impairs inositol trisphosphates (IP3)-linked ER to mitochondria Ca2+ transfer. This phenomenon is dependent on the capacity of TOM70 to interact with IP3-receptors and favor their functional recruitment close to mitochondria. Importantly, the reduced constitutive Ca2+ transfer to mitochondria, observed in TOM70-depleted cells, dampens mitochondrial respiration, affects cell bioenergetics, induces autophagy, and inhibits proliferation. Our data reveal a hitherto unexpected role for TOM70 in pro-survival ER-mitochondria communication, reinforcing the view that the ER-mitochondria signaling platform is a key regulator of cell fate.
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Ruge H, Flosdorff S, Ebersberger I, Chigri F, Vothknecht UC. The calmodulin-like proteins AtCML4 and AtCML5 are single-pass membrane proteins targeted to the endomembrane system by an N-terminal signal anchor sequence. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3985-96. [PMID: 27029353 PMCID: PMC4915527 DOI: 10.1093/jxb/erw101] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Calmodulins (CaMs) are important mediators of Ca(2+) signals that are found ubiquitously in all eukaryotic organisms. Plants contain a unique family of calmodulin-like proteins (CMLs) that exhibit greater sequence variance compared to canonical CaMs. The Arabidopsis thaliana proteins AtCML4 and AtCML5 are members of CML subfamily VII and possess a CaM domain comprising the characteristic double pair of EF-hands, but they are distinguished from other members of this subfamily and from canonical CaMs by an N-terminal extension of their amino acid sequence. Transient expression of yellow fluorescent protein-tagged AtCML4 and AtCML5 under a 35S-promoter in Nicotiana benthamiana leaf cells revealed a spherical fluorescence pattern. This pattern was confirmed by transient expression in Arabidopsis protoplasts under the native promoter. Co-localization analyses with various endomembrane marker proteins suggest that AtCML4 and AtCML5 are localized to vesicular structures in the interphase between Golgi and the endosomal system. Further studies revealed AtCML5 to be a single-pass membrane protein that is targeted into the endomembrane system by an N-terminal signal anchor sequence. Self-assembly green fluorescent protein and protease protection assays support a topology with the CaM domain exposed to the cytosolic surface and not the lumen of the vesicles, indicating that AtCML5 could sense Ca(2+) signals in the cytosol. Phylogenetic analysis suggests that AtCML4 and AtCML5 are closely related paralogues originating from a duplication event within the Brassicaceae family. CML4/5-like proteins seem to be universally present in eudicots but are absent in some monocots. Together these results show that CML4/5-like proteins represent a flowering plant-specific subfamily of CMLs with a potential function in vesicle transport within the plant endomembrane system.
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Affiliation(s)
- Henning Ruge
- Department of Biology I, Faculty of Biology, LMU Munich, Großhaderner Straße 2-4, D-82152 Planegg, Germany
| | - Sandra Flosdorff
- Department of Biology I, Faculty of Biology, LMU Munich, Großhaderner Straße 2-4, D-82152 Planegg, Germany
| | - Ingo Ebersberger
- Department for Applied Bioinformatics, Institute for Cell Biology and Neuroscience, Goethe-University Frankfurt, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany
| | - Fatima Chigri
- Department of Biology I, Faculty of Biology, LMU Munich, Großhaderner Straße 2-4, D-82152 Planegg, Germany Center for Integrated Protein Science (Munich) at the Department of Biology I, Faculty of Biology, LMU Munich, D-81377 Munich, Germany
| | - Ute C Vothknecht
- Department of Biology I, Faculty of Biology, LMU Munich, Großhaderner Straße 2-4, D-82152 Planegg, Germany Center for Integrated Protein Science (Munich) at the Department of Biology I, Faculty of Biology, LMU Munich, D-81377 Munich, Germany
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8
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Murcha MW, Kmiec B, Kubiszewski-Jakubiak S, Teixeira PF, Glaser E, Whelan J. Protein import into plant mitochondria: signals, machinery, processing, and regulation. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:6301-35. [PMID: 25324401 DOI: 10.1093/jxb/eru399] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The majority of more than 1000 proteins present in mitochondria are imported from nuclear-encoded, cytosolically synthesized precursor proteins. This impressive feat of transport and sorting is achieved by the combined action of targeting signals on mitochondrial proteins and the mitochondrial protein import apparatus. The mitochondrial protein import apparatus is composed of a number of multi-subunit protein complexes that recognize, translocate, and assemble mitochondrial proteins into functional complexes. While the core subunits involved in mitochondrial protein import are well conserved across wide phylogenetic gaps, the accessory subunits of these complexes differ in identity and/or function when plants are compared with Saccharomyces cerevisiae (yeast), the model system for mitochondrial protein import. These differences include distinct protein import receptors in plants, different mechanistic operation of the intermembrane protein import system, the location and activity of peptidases, the function of inner-membrane translocases in linking the outer and inner membrane, and the association/regulation of mitochondrial protein import complexes with components of the respiratory chain. Additionally, plant mitochondria share proteins with plastids, i.e. dual-targeted proteins. Also, the developmental and cell-specific nature of mitochondrial biogenesis is an aspect not observed in single-celled systems that is readily apparent in studies in plants. This means that plants provide a valuable model system to study the various regulatory processes associated with protein import and mitochondrial biogenesis.
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Affiliation(s)
- Monika W Murcha
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia
| | - Beata Kmiec
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, SE-10691 Stockholm, Sweden
| | - Szymon Kubiszewski-Jakubiak
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia
| | - Pedro F Teixeira
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, SE-10691 Stockholm, Sweden
| | - Elzbieta Glaser
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, SE-10691 Stockholm, Sweden
| | - James Whelan
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria, 3086, Australia
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Ng S, De Clercq I, Van Aken O, Law SR, Ivanova A, Willems P, Giraud E, Van Breusegem F, Whelan J. Anterograde and retrograde regulation of nuclear genes encoding mitochondrial proteins during growth, development, and stress. MOLECULAR PLANT 2014; 7:1075-93. [PMID: 24711293 DOI: 10.1093/mp/ssu037] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Mitochondrial biogenesis and function in plants require the expression of over 1000 nuclear genes encoding mitochondrial proteins (NGEMPs). The expression of these genes is regulated by tissue-specific, developmental, internal, and external stimuli that result in a dynamic organelle involved in both metabolic and a variety of signaling processes. Although the metabolic and biosynthetic machinery of mitochondria is relatively well understood, the factors that regulate these processes and the various signaling pathways involved are only beginning to be identified at a molecular level. The molecular components of anterograde (nuclear to mitochondrial) and retrograde (mitochondrial to nuclear) signaling pathways that regulate the expression of NGEMPs interact with chloroplast-, growth-, and stress-signaling pathways in the cell at a variety of levels, with common components involved in transmission and execution of these signals. This positions mitochondria as important hubs for signaling in the cell, not only in direct signaling of mitochondrial function per se, but also in sensing and/or integrating a variety of other internal and external signals. This integrates and optimizes growth with energy metabolism and stress responses, which is required in both photosynthetic and non-photosynthetic cells.
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Affiliation(s)
- Sophia Ng
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Australia Joint Research Laboratory in Genomics and Nutriomics, College of Life Sciences, Zhejiang University, Hangzhou, 310058, P.R. China
| | - Inge De Clercq
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium
| | - Olivier Van Aken
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Australia
| | - Simon R Law
- Department of Botany, ARC Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora 3086, Victoria, Australia
| | - Aneta Ivanova
- Department of Botany, ARC Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora 3086, Victoria, Australia
| | - Patrick Willems
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium Department of Medical Protein Research and Department of Biochemistry, 9000 Ghent, Belgium
| | - Estelle Giraud
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Australia Present address: Illumina, ANZ, 1 International Court, Scoresby Victoria 3179, Australia
| | - Frank Van Breusegem
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium
| | - James Whelan
- Department of Botany, ARC Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora 3086, Victoria, Australia
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Harbauer AB, Zahedi RP, Sickmann A, Pfanner N, Meisinger C. The protein import machinery of mitochondria-a regulatory hub in metabolism, stress, and disease. Cell Metab 2014; 19:357-72. [PMID: 24561263 DOI: 10.1016/j.cmet.2014.01.010] [Citation(s) in RCA: 282] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mitochondria fulfill central functions in bioenergetics, metabolism, and apoptosis. They import more than 1,000 different proteins from the cytosol. It had been assumed that the protein import machinery is constitutively active and not subject to detailed regulation. However, recent studies indicate that mitochondrial protein import is regulated at multiple levels connected to cellular metabolism, signaling, stress, and pathogenesis of diseases. Here, we discuss the molecular mechanisms of import regulation and their implications for mitochondrial homeostasis. The protein import activity can function as a sensor of mitochondrial fitness and provides a direct means of regulating biogenesis, composition, and turnover of the organelle.
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Affiliation(s)
- Angelika B Harbauer
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; Trinationales Graduiertenkolleg 1478, Universität Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Universität Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany
| | - René P Zahedi
- Leibniz-Institute for Analytical Sciences-ISAS-e.V., 44139 Dortmund, Germany
| | - Albert Sickmann
- Leibniz-Institute for Analytical Sciences-ISAS-e.V., 44139 Dortmund, Germany; Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Nikolaus Pfanner
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany.
| | - Chris Meisinger
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany.
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Araújo WL, Nunes-Nesi A, Fernie AR. On the role of plant mitochondrial metabolism and its impact on photosynthesis in both optimal and sub-optimal growth conditions. PHOTOSYNTHESIS RESEARCH 2014; 119:141-156. [PMID: 23456269 DOI: 10.1007/s11120-013-9807-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 02/18/2013] [Indexed: 06/01/2023]
Abstract
Given that the pathways of photosynthesis and respiration catalyze partially opposing processes, it follows that their relative activities must be carefully regulated within plant cells. Recent evidence has shown that the components of the mitochondrial electron transport chain are essential for the proper maintenance of intracellular redox gradients, to allow considerable rates of photorespiration and in turn efficient photosynthesis. Thus considerable advances have been made in understanding the interaction between respiration and photosynthesis during the last decades and the potential mechanisms linking mitochondrial function and photosynthetic efficiency will be reviewed. Despite the fact that manipulation of various steps of mitochondrial metabolism has been demonstrated to alter photosynthesis under optimal growth conditions, it is likely that these changes will, by and large, not be maintained under sub-optimal situations. Therefore producing plants to meet this aim remains a critical challenge. It is clear, however, that although there have been a range of studies analysing changes in respiratory and photosynthetic rates in response to light, temperature and CO2, our knowledge of the environmental impact on these processes and its linkage still remains fragmented. We will also discuss the metabolic changes associated to plant respiration and photosynthesis as important components of the survival strategy as they considerably extend the period that a plant can withstand to a stress situation.
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Affiliation(s)
- Wagner L Araújo
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, 36570-000, Brazil
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12
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Novel role of calmodulin in regulating protein transport to mitochondria in a unicellular eukaryote. Mol Cell Biol 2013; 33:4579-93. [PMID: 24043313 DOI: 10.1128/mcb.00829-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Lower eukaryotes like the kinetoplastid parasites are good models to study evolution of cellular pathways during steps to eukaryogenesis. In this study, a kinetoplastid parasite, Leishmania donovani, was used to understand the process of mitochondrial translocation of a nucleus-encoded mitochondrial protein, the mitochondrial tryparedoxin peroxidase (mTXNPx). We report the presence of an N-terminal cleavable mitochondrial targeting signal (MTS) validated through deletion and grafting experiments. We also establish a novel finding of calmodulin (CaM) binding to the MTS of mTXNPx through specific residues. Mutation of CaM binding residues, keeping intact the residues involved in mitochondrial targeting and biochemical inhibition of CaM activity both in vitro and in vivo, prevented mitochondrial translocation. Through reconstituted import assays, we demonstrate obstruction of mitochondrial translocation either in the absence of CaM or Ca(2+) or in the presence of CaM inhibitors. We also demonstrate the prevention of temperature-driven mTXNPx aggregation in the presence of CaM. These findings establish the idea that CaM is required for the transport of the protein to mitochondria through maintenance of translocation competence posttranslation.
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Abstract
SIGNIFICANCE For a plant to grow and develop, energy and appropriate building blocks are a fundamental requirement. Mitochondrial respiration is a vital source for both. The delicate redox processes that make up respiration are affected by the plant's changing environment. Therefore, mitochondrial regulation is critically important to maintain cellular homeostasis. This involves sensing signals from changes in mitochondrial physiology, transducing this information, and mounting tailored responses, by either adjusting mitochondrial and cellular functions directly or reprogramming gene expression. RECENT ADVANCES Retrograde (RTG) signaling, by which mitochondrial signals control nuclear gene expression, has been a field of very active research in recent years. Nevertheless, no mitochondrial RTG-signaling pathway is yet understood in plants. This review summarizes recent advances toward elucidating redox processes and other bioenergetic factors as a part of RTG signaling of plant mitochondria. CRITICAL ISSUES Novel insights into mitochondrial physiology and redox-regulation provide a framework of upstream signaling. On the other end, downstream responses to modified mitochondrial function have become available, including transcriptomic data and mitochondrial phenotypes, revealing processes in the plant that are under mitochondrial control. FUTURE DIRECTIONS Drawing parallels to chloroplast signaling and mitochondrial signaling in animal systems allows to bridge gaps in the current understanding and to deduce promising directions for future research. It is proposed that targeted usage of new technical approaches, such as quantitative in vivo imaging, will provide novel leverage to the dissection of plant mitochondrial signaling.
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14
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Chigri F, Flosdorff S, Pilz S, Kölle E, Dolze E, Gietl C, Vothknecht UC. The Arabidopsis calmodulin-like proteins AtCML30 and AtCML3 are targeted to mitochondria and peroxisomes, respectively. PLANT MOLECULAR BIOLOGY 2012; 78:211-22. [PMID: 22116655 DOI: 10.1007/s11103-011-9856-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 11/08/2011] [Indexed: 05/24/2023]
Abstract
Calmodulin (CaM) is a ubiquitous sensor/transducer of calcium signals in eukaryotic organisms. While CaM mediated calcium regulation of cytosolic processes is well established, there is growing evidence for the inclusion of organelles such as chloroplasts, mitochondria and peroxisomes into the calcium/calmodulin regulation network. A number of CaM-binding proteins have been identified in these organelles and processes such as protein import into chloroplasts and mitochondria have been shown to be governed by CaM regulation. What have been missing to date are the mediators of this regulation since no CaM or calmodulin-like protein (CML) has been identified in any of these organelles. Here we show that two Arabidopsis CMLs, AtCML3 and AtCML30, are localized in peroxisomes and mitochondria, respectively. AtCML3 is targeted via an unusual C-terminal PTS1-like tripeptide while AtCML30 utilizes an N-terminal, non-cleavable transit peptide. Both proteins possess the typical structure of CaMs, with two pairs of EF-hand motifs separated by a short linker domain. They furthermore display common characteristics, such as calcium-dependent alteration of gel mobility and calcium-dependent exposure of a hydrophobic surface. This indicates that they can function in a similar manner as canonical CaMs. The presence of close homologues to AtCML3 and AtCML30 in other plants further indicates that organellar targeting of these CMLs is not a specific feature of Arabidopsis. The identification of peroxisomal and mitochondrial CMLs is an important step in the understanding how these organelles are integrated into the cellular calcium/calmodulin signaling pathways.
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Affiliation(s)
- Fatima Chigri
- Department of Biology of the LMU Munich, Center for Integrated Protein Science (Munich), 82152 Martinsried, Germany
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Stael S, Wurzinger B, Mair A, Mehlmer N, Vothknecht UC, Teige M. Plant organellar calcium signalling: an emerging field. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1525-42. [PMID: 22200666 PMCID: PMC3966264 DOI: 10.1093/jxb/err394] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
This review provides a comprehensive overview of the established and emerging roles that organelles play in calcium signalling. The function of calcium as a secondary messenger in signal transduction networks is well documented in all eukaryotic organisms, but so far existing reviews have hardly addressed the role of organelles in calcium signalling, except for the nucleus. Therefore, a brief overview on the main calcium stores in plants-the vacuole, the endoplasmic reticulum, and the apoplast-is provided and knowledge on the regulation of calcium concentrations in different cellular compartments is summarized. The main focus of the review will be the calcium handling properties of chloroplasts, mitochondria, and peroxisomes. Recently, it became clear that these organelles not only undergo calcium regulation themselves, but are able to influence the Ca(2+) signalling pathways of the cytoplasm and the entire cell. Furthermore, the relevance of recent discoveries in the animal field for the regulation of organellar calcium signals will be discussed and conclusions will be drawn regarding potential homologous mechanisms in plant cells. Finally, a short overview on bacterial calcium signalling is included to provide some ideas on the question where this typically eukaryotic signalling mechanism could have originated from during evolution.
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Affiliation(s)
- Simon Stael
- Department of Biochemistry and Cell Biology, MFPL, University of Vienna, Dr Bohrgasse 9, A-1030 Vienna, Austria
| | - Bernhard Wurzinger
- Department of Biochemistry and Cell Biology, MFPL, University of Vienna, Dr Bohrgasse 9, A-1030 Vienna, Austria
| | - Andrea Mair
- Department of Biochemistry and Cell Biology, MFPL, University of Vienna, Dr Bohrgasse 9, A-1030 Vienna, Austria
| | - Norbert Mehlmer
- Department of Biology I, Botany, LMU Munich, Großhaderner Str. 2, D-82152 Planegg-Martinsried, Germany
| | - Ute C. Vothknecht
- Department of Biology I, Botany, LMU Munich, Großhaderner Str. 2, D-82152 Planegg-Martinsried, Germany
- Center for Integrated Protein Science (Munich) at the Department of Biology of the LMU Munich, D-81377 Munich, Germany
| | - Markus Teige
- Department of Biochemistry and Cell Biology, MFPL, University of Vienna, Dr Bohrgasse 9, A-1030 Vienna, Austria
- To whom correspondence should be addressed.
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Machettira AB, Groß LE, Tillmann B, Weis BL, Englich G, Sommer MS, Königer M, Schleiff E. Protein-induced modulation of chloroplast membrane morphology. FRONTIERS IN PLANT SCIENCE 2012; 2:118. [PMID: 22639631 PMCID: PMC3355639 DOI: 10.3389/fpls.2011.00118] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 12/29/2011] [Indexed: 05/24/2023]
Abstract
Organelles are surrounded by membranes with a distinct lipid and protein composition. While it is well established that lipids affect protein functioning and vice versa, it has been only recently suggested that elevated membrane protein concentrations may affect the shape and organization of membranes. We therefore analyzed the effects of high chloroplast envelope protein concentrations on membrane structures using an in vivo approach with protoplasts. Transient expression of outer envelope proteins or protein domains such as CHUP1-TM-GFP, outer envelope protein of 7 kDa-GFP, or outer envelope protein of 24 kDa-GFP at high levels led to the formation of punctate, circular, and tubular membrane protrusions. Expression of inner membrane proteins such as translocase of inner chloroplast membrane 20, isoform II (Tic20-II)-GFP led to membrane protrusions including invaginations. Using increasing amounts of DNA for transfection, we could show that the frequency, size, and intensity of these protrusions increased with protein concentration. The membrane deformations were absent after cycloheximide treatment. Co-expression of CHUP1-TM-Cherry and Tic20-II-GFP led to membrane protrusions of various shapes and sizes including some stromule-like structures, for which several functions have been proposed. Interestingly, some structures seemed to contain both proteins, while others seem to contain one protein exclusively, indicating that outer and inner envelope dynamics might be regulated independently. While it was more difficult to investigate the effects of high expression levels of membrane proteins on mitochondrial membrane shapes using confocal imaging, it was striking that the expression of the outer membrane protein Tom20 led to more elongate mitochondria. We discuss that the effect of protein concentrations on membrane structure is possibly caused by an imbalance in the lipid to protein ratio and may be involved in a signaling pathway regulating membrane biogenesis. Finally, the observed phenomenon provides a valuable experimental approach to investigate the relationship between lipid synthesis and membrane protein expression in future studies.
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Affiliation(s)
- Anu B. Machettira
- Molecular Cell Biology of Plants, Johann-Wolfgang-Goethe University FrankfurtFrankfurt am Main, Germany
| | - Lucia E. Groß
- Molecular Cell Biology of Plants, Johann-Wolfgang-Goethe University FrankfurtFrankfurt am Main, Germany
| | - Bodo Tillmann
- Molecular Cell Biology of Plants, Johann-Wolfgang-Goethe University FrankfurtFrankfurt am Main, Germany
| | - Benjamin L. Weis
- Molecular Cell Biology of Plants, Johann-Wolfgang-Goethe University FrankfurtFrankfurt am Main, Germany
| | - Gisela Englich
- Molecular Cell Biology of Plants, Johann-Wolfgang-Goethe University FrankfurtFrankfurt am Main, Germany
| | - Maik S. Sommer
- Molecular Cell Biology of Plants, Johann-Wolfgang-Goethe University FrankfurtFrankfurt am Main, Germany
| | - Martina Königer
- Department of Biological Sciences, Wellesley CollegeWellesley, MA, USA
| | - Enrico Schleiff
- Molecular Cell Biology of Plants, Johann-Wolfgang-Goethe University FrankfurtFrankfurt am Main, Germany
- Cluster of Excellence “Macromolecular Complexes”, Johann-Wolfgang-Goethe University FrankfurtFrankfurt am Main, Germany
- Department of Biosciences, Center of Membrane Proteomics, Johann-Wolfgang-Goethe University FrankfurtFrankfurt am Main, Germany
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Wang WQ, Cheng HY, Møller IM, Song SQ. The role of recovery of mitochondrial structure and function in desiccation tolerance of pea seeds. PHYSIOLOGIA PLANTARUM 2012; 144:20-34. [PMID: 21910735 DOI: 10.1111/j.1399-3054.2011.01518.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Mitochondrial repair is of fundamental importance for seed germination. When mature orthodox seeds are imbibed and germinated, they lose their desiccation tolerance in parallel. To gain a better understanding of this process, we studied the recovery of mitochondrial structure and function in pea (Pisum sativum cv. Jizhuang) seeds with different tolerance to desiccation. Mitochondria were isolated and purified from the embryo axes of control and imbibed-dehydrated pea seeds after (re-)imbibition for various times. Recovery of mitochondrial structure and function occurred both in control and imbibed-dehydrated seed embryo axes, but at different rates and to different maximum levels. The integrity of the outer mitochondrial membrane reached 96% in all treatments. However, only the seeds imbibed for 12 h and then dehydrated recovered the integrity of the inner mitochondrial membrane (IMM) and State 3 (respiratory state in which substrate and ADP are present) respiration (with NADH and succinate as substrate) to the control level after re-imbibition. With increasing imbibition time, the degree to which each parameter recovered decreased in parallel with the decrease in desiccation tolerance. The tolerance of imbibed seeds to desiccation increased and decreased when imbibed in CaCl(2) and methylviologen solution, respectively, and the recovery of the IMM integrity similarly improved and weakened in these two treatments, respectively. Survival of seeds after imbibition-dehydration linearly increased with the increase in ability to recover the integrity of IMM and State 3 respiration, which indicates that recovery of mitochondrial structure and function during germination has an important role in seed desiccation tolerance.
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Affiliation(s)
- Wei-Qing Wang
- Group of Seed Physiology and Biotechnology, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
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Duke SO, Dayan FE. Modes of action of microbially-produced phytotoxins. Toxins (Basel) 2011; 3:1038-1064. [PMID: 22069756 PMCID: PMC3202864 DOI: 10.3390/toxins3081038] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 08/15/2011] [Accepted: 08/17/2011] [Indexed: 01/17/2023] Open
Abstract
Some of the most potent phytotoxins are synthesized by microbes. A few of these share molecular target sites with some synthetic herbicides, but many microbial toxins have unique target sites with potential for exploitation by the herbicide industry. Compounds from both non-pathogenic and pathogenic microbes are discussed. Microbial phytotoxins with modes of action the same as those of commercial herbicides and those with novel modes of action of action are covered. Examples of the compounds discussed are tentoxin, AAL-toxin, auscaulitoxin aglycone, hydantocidin, thaxtomin, and tabtoxin.
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Affiliation(s)
- Stephen O. Duke
- United States Department of Agriculture, Agricultural Research Service, Natural Products Utilization Research Unit, P. O. Box 8048, MS 38677, USA;
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Protein import into chloroplasts: the Tic complex and its regulation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:740-7. [PMID: 20100520 DOI: 10.1016/j.bbamcr.2010.01.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 01/11/2010] [Accepted: 01/13/2010] [Indexed: 11/24/2022]
Abstract
Chloroplasts like mitochondria were derived from an endosymbiontic event. Due to the massive gene transfer to the nucleus during endosymbiosis, only a limited number of chloroplastic proteins are still encoded for in the plastid genome. Most of the nuclear-encoded plastidic proteins are post-translationally translocated back to the chloroplast via the general import pathway through distinct outer and inner envelope membrane protein complexes, the Toc and Tic translocons (Translocon at the outer/inner envelope membrane of chloroplasts). Eight Tic subunits have been described so far, including two potential channel proteins (Tic110 and Tic20), the "motor complex" (Tic40 associated with the stromal chaperone Hsp93) and the "redox regulon" (Tic62, Tic55, and Tic32) involved in regulation of protein import via the metabolic redox status of the chloroplast. Regulation can additionally occur via thioredoxins (Tic110 and Tic55) or via the calcium/calmodulin network (Tic110 and Tic32). In this review we present the current knowledge about the Tic complex focusing on its regulation and addressing some still open questions.
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Bussemer J, Vothknecht UC, Chigri F. Calcium regulation in endosymbiotic organelles of plants. PLANT SIGNALING & BEHAVIOR 2009; 4:805-8. [PMID: 19847100 PMCID: PMC2802815 DOI: 10.4161/psb.4.9.9234] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2009] [Accepted: 08/06/2009] [Indexed: 05/28/2023]
Abstract
In plant cells calcium-dependent signaling pathways are involved in a large array of biological processes in response to hormones, biotic/abiotic stress signals and a variety of developmental cues. This is generally achieved through binding of calcium to diverse calcium-sensing proteins, which subsequently control downstream events by activating or inhibiting biochemical reactions. Regulation by calcium is considered as a eukaryotic trait and has not been described for prokaryotes. Nevertheless, there is increasing evidence indicating that organelles of prokaryotic origin, such as chloroplasts and mitochondria, are integrated into the calcium-signaling network of the cell. An important transducer of calcium in these organelles appears to be calmodulin. In this review we want to give an overview over present data showing that endosymbiotic organelles harbour calcium-dependent biological processes with a focus on calmodulin-regulation.
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Bussemer J, Chigri F, Vothknecht UC. Arabidopsis ATPase family gene 1-like protein 1 is a calmodulin-binding AAA+-ATPase with a dual localization in chloroplasts and mitochondria. FEBS J 2009; 276:3870-80. [PMID: 19523112 DOI: 10.1111/j.1742-4658.2009.07102.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Members of the AAA(+)-ATPase superfamily (ATPases associated with various cellular activities) are found in all kingdoms of life and they are involved in very diverse cellular processes, including protein degradation, membrane fusion or cell division. The Arabidopsis genome encodes approximately 140 different proteins that are putative members of this superfamily, although the exact function of most of these proteins remains unknown. Using affinity chromatography on calmodulin-agarose with chloroplast proteins, we purified a 50 kDa protein encoded by AT4G30490 with similarity to the ATPase family gene 1 protein from yeast. Structural analysis showed that the protein possesses a single AAA-domain characteristic for members of the AAA(+)-ATPase superfamily and that this contains all features specific to proteins of the ATPase family gene 1-like subfamily. In vitro pull-down as well as cross-linking assays corroborate calcium-dependent binding of the protein to calmodulin. The calmodulin binding domain could be located to a region of 20 amino acids within the AAA-domain in close proximity to the Walker A motif. Our analysis further showed that the protein is localized in both mitochondria and chloroplasts, further supporting the incorporation of both endosymbiotic organelles into the calcium-signaling network of the cell. Localization of the same calmodulin-binding protein into mitochondria and chloroplasts could be a means to provide a coordinated regulation of processes in both organelles by calcium signals.
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Affiliation(s)
- Johanna Bussemer
- Department of Biology I, LMU Munich, Planegg-Martinsried, Germany
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