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Matiolli CC, Soares RC, Alves HLS, Abreu IA. Turning the Knobs: The Impact of Post-translational Modifications on Carbon Metabolism. FRONTIERS IN PLANT SCIENCE 2022; 12:781508. [PMID: 35087551 PMCID: PMC8787203 DOI: 10.3389/fpls.2021.781508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
Plants rely on the carbon fixed by photosynthesis into sugars to grow and reproduce. However, plants often face non-ideal conditions caused by biotic and abiotic stresses. These constraints impose challenges to managing sugars, the most valuable plant asset. Hence, the precise management of sugars is crucial to avoid starvation under adverse conditions and sustain growth. This review explores the role of post-translational modifications (PTMs) in the modulation of carbon metabolism. PTMs consist of chemical modifications of proteins that change protein properties, including protein-protein interaction preferences, enzymatic activity, stability, and subcellular localization. We provide a holistic view of how PTMs tune resource distribution among different physiological processes to optimize plant fitness.
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Okuzaki A, Rühle T, Leister D, Schmitz-Linneweber C. The acidic domain of the chloroplast RNA-binding protein CP31A supports cold tolerance in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4904-4914. [PMID: 33872351 DOI: 10.1093/jxb/erab165] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
The processing of chloroplast RNA requires a large number of nuclear-encoded RNA-binding proteins (RBPs) that are imported post-translationally into the organelle. The chloroplast ribonucleoprotein 31A (CP31A) supports RNA editing at 13 sites and also supports the accumulation of multiple chloroplast mRNAs. In cp31a mutants it is the ndhF mRNA (coding for a subunit of the NDH complex) that is most strongly affected. CP31A becomes particularly important at low temperatures, where it is essential for chloroplast development in young tissue. Next to two RNA-recognition motifs (RRMs), CP31A has an N-terminal acidic domain that is phosphorylated at several sites. We investigated the function of the acidic domain in the role of CP31A in RNA metabolism and cold resistance. Using point mutagenesis, we demonstrate that the known phosphorylation sites within the acidic domain are irrelevant for any of the known functions of CP31A, both at normal and at low temperatures. Even when the entire acidic domain is removed, no effects on RNA editing were observed. By contrast, loss of the acidic domain reduced the ability of CP31A to stabilize the ndhF mRNA, which was associated with reduced NDH complex activity. Most importantly, acidic domain-less CP31A lines displayed bleached young tissue in the cold. Together, these data show that the different functions of CP31A can be assigned to different regions of the protein: the RRMs are sufficient to maintain RNA editing and to allow the accumulation of basal amounts of ndhF mRNA, while chloroplast development under cold conditions critically depends on the acidic domain.
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Affiliation(s)
- Ayako Okuzaki
- Molecular Genetics, Humboldt-University Berlin, Philippstr.13, Berlin, Germany
| | - Thilo Rühle
- Plant Molecular Biology, Department of Biology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Dario Leister
- Plant Molecular Biology, Department of Biology, Ludwig Maximilian University of Munich, Munich, Germany
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3
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PhosPhAt 4.0: An Updated Arabidopsis Database for Searching Phosphorylation Sites and Kinase-Target Interactions. Methods Mol Biol 2021; 2358:189-202. [PMID: 34270056 DOI: 10.1007/978-1-0716-1625-3_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The PhosPhAt 4.0 database contains information on Arabidopsis phosphorylation sites identified by mass spectrometry in large-scale experiments from different research groups. So far PhosPhAt 4.0 has been one of the most significant large-scale data resources for plant phosphorylation studies. Functionalities of the web application, besides display of phosphorylation sites, include phosphorylation site prediction and kinase-target relationships retrieval. Here, we present an overview and user instructions for the PhosPhAt 4.0 database, with strong emphasis on recent renewals regarding protein annotation by SUBA4.0 and Mapman4, and additional phosphorylation site information imported from other databases, such as UniProt. Here, we provide a user guide for the retrieval of phosphorylation motifs from the kinase-target database and how to visualize these results. The improvements incorporated into the PhosPhAt 4.0 database have produced much more functionality and user flexibility for phosphoproteomic analysis.
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Rödiger A, Galonska J, Bergner E, Agne B, Helm S, Alseekh S, Fernie AR, Thieme D, Hoehenwarter W, Hause G, Pfannschmidt T, Baginsky S. Working day and night: plastid casein kinase 2 catalyses phosphorylation of proteins with diverse functions in light- and dark-adapted plastids. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:546-558. [PMID: 32745315 DOI: 10.1111/tpj.14944] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 07/15/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
Casein kinase 2 is a ubiquitous protein kinase that has puzzled researchers for several decades because of its pleiotropic activity. Here, we set out to identify the in vivo targets of plastid casein kinase 2 (pCK2) in Arabidopsis thaliana. Survey phosphoproteome analyses were combined with targeted analyses with wild-type and pck2 knockdown mutants to identify potential pCK2 targets by their decreased phosphorylation state in the mutant. To validate potential substrates, we complemented the pck2 knockdown line with tandem affinity tag (TAP)-tagged pCK2 and found it to restore growth parameters, as well as many, but not all, putative pCK2-dependent phosphorylation events. We further performed a targeted analysis at the end-of-night to increase the specificity of target protein identification. This analysis confirmed light-independent phosphorylation of several pCK2 target proteins. Based on the aforementioned data, we define a set of in vivo pCK2-targets that span different chloroplast functions, such as metabolism, transcription, translation and photosynthesis. The pleiotropy of pCK2 functions is also manifested by altered state transition kinetics during short-term acclimation and significant alterations in the mutant metabolism, supporting its function in photosynthetic regulation. Thus, our data expand our understanding on chloroplast phosphorylation networks and provide insights into kinase networks in the regulation of chloroplast functions.
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Affiliation(s)
- Anja Rödiger
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Charles Tanford Proteinzentrum, Kurt-Mothes-Str. 3a, Halle (Saale), 06120, Germany
| | - Johann Galonska
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Charles Tanford Proteinzentrum, Kurt-Mothes-Str. 3a, Halle (Saale), 06120, Germany
| | - Elena Bergner
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Charles Tanford Proteinzentrum, Kurt-Mothes-Str. 3a, Halle (Saale), 06120, Germany
| | - Birgit Agne
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Charles Tanford Proteinzentrum, Kurt-Mothes-Str. 3a, Halle (Saale), 06120, Germany
| | - Stefan Helm
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Charles Tanford Proteinzentrum, Kurt-Mothes-Str. 3a, Halle (Saale), 06120, Germany
| | - Saleh Alseekh
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Wissenschaftspark Golm, Potsdam, 14476, Germany
| | - Alisdair R Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Wissenschaftspark Golm, Potsdam, 14476, Germany
| | - Domenika Thieme
- Leibniz-Institut für Pflanzenbiochemie, Weinbergweg 3, Halle (Saale), 06120, Germany
| | - Wolfgang Hoehenwarter
- Leibniz-Institut für Pflanzenbiochemie, Weinbergweg 3, Halle (Saale), 06120, Germany
| | - Gerd Hause
- Biocentre, Martin-Luther-University Halle-Wittenberg, Weinbergweg 22, Halle (Saale), 06120, Germany
| | | | - Sacha Baginsky
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Charles Tanford Proteinzentrum, Kurt-Mothes-Str. 3a, Halle (Saale), 06120, Germany
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5
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Patterson JA, Tetlow IJ, Emes MJ. Bioinformatic and in vitro Analyses of Arabidopsis Starch Synthase 2 Reveal Post-translational Regulatory Mechanisms. FRONTIERS IN PLANT SCIENCE 2018; 9:1338. [PMID: 30283470 PMCID: PMC6156364 DOI: 10.3389/fpls.2018.01338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 08/24/2018] [Indexed: 05/13/2023]
Abstract
Starch synthase 2 (SS2) is an important enzyme in leaf starch synthesis, elongating intermediate-length glucan chains. Loss of SS2 results in a distorted starch granule phenotype and altered physiochemical properties, highlighting its importance in starch biosynthesis, however, the post-translational regulation of SS2 is poorly understood. In this study, a combination of bioinformatic and in vitro analysis of recombinant SS2 was used to identify and characterize SS2 post-translational regulatory mechanisms. The SS2 N-terminal region, comprising the first 185 amino acids of the mature protein sequence, was shown to be highly variable between species, and was predicted to be intrinsically disordered. Intrinsic disorder in proteins is often correlated with protein phosphorylation and protein-protein interactions. Recombinant Arabidopsis thaliana SS2 formed homodimers that required the N-terminal region, but N-terminal peptides could not form stable homodimers alone. Recombinant SS2 was shown to be phosphorylated by chloroplast protein kinases and recombinant casein kinase II at two N-terminal serine residues (S63, S65), but mutation of these phosphorylation sites (Ser>Ala) revealed that they are not required for homo-dimerization. Heteromeric enzyme complex (HEC) formation between SS2 and SBE2.2 was shown to be ATP-dependent. However, SS2 homo-dimerization and protein phosphorylation are not required for its interaction with SBE2.2, as truncation of the SS2 N-terminus did not disrupt ATP-dependent HEC assembly. SS2 phosphorylation had no affect on its catalytic activity. Intriguingly, the removal of the N-terminal region of SS2 resulted in a 47-fold increase in its activity. As N-terminal truncation disrupted dimerization, this suggests that SS2 is more active when monomeric, and that transitions between oligomeric state may be a mechanism for SS2 regulation.
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Affiliation(s)
| | | | - Michael J. Emes
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
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6
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Yu QB, Zhao TT, Ye LS, Cheng L, Wu YQ, Huang C, Yang ZN. pTAC10, an S1-domain-containing component of the transcriptionally active chromosome complex, is essential for plastid gene expression in Arabidopsis thaliana and is phosphorylated by chloroplast-targeted casein kinase II. PHOTOSYNTHESIS RESEARCH 2018; 137:69-83. [PMID: 29330702 DOI: 10.1007/s11120-018-0479-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 12/28/2017] [Indexed: 06/07/2023]
Abstract
In higher plant chloroplasts, the plastid-encoded RNA polymerase (PEP) consists of four catalytic subunits and numerous nuclear-encoded accessory proteins, including pTAC10, an S1-domain-containing protein. In this study, pTAC10 knockout lines were characterized. Two ptac10 mutants had an albino phenotype and severely impaired chloroplast development. The pTAC10 genomic sequence fused to a four-tandem MYC tag driven by its own promoter functionally complemented the ptac10-1 mutant phenotype. pTAC10 was present in both the chloroplast stroma and thylakoids. Two-dimensional blue native polyacrylamide gel electrophoresis (BN-PAGE), and immunoblotting assays showed that pTAC10:MYC co-migrates with one of the PEP core subunits, RpoB. A comprehensive investigation of the plastid gene expression profiles by quantitative RT-PCR revealed that, compared with wild-type plants, the abundance of PEP-dependent plastid transcripts is severely decreased in the ptac10-1 mutant, while the amount of plastid transcripts exclusively transcribed by NEP either barely changes or even increases. RNA blot analysis confirmed that PEP-dependent chloroplast transcripts, including psaB, psbA and rbcL, substantially decrease in the ptac10-1 mutant. Immunoblotting showed reduced accumulation of most chloroplast proteins in the ptac10 mutants. These data indicate the essential role of pTAC10 in plastid gene expression and plastid development. pTAC10 interacts with chloroplast-targeted casein kinase 2 (cpCK2) in vitro and in vivo and can be phosphorylated by Arabidopsis cpCK2 in vitro at sites Ser95, Ser396 and Ser434. RNA-EMSA assays showed that pTAC10 is able to bind to the psbA, atpE and accD transcripts, suggesting a non-specific RNA-binding activity of pTAC10. The RNA affinity of pTAC10 was enhanced by phosphorylation and decreased by the amino acid substitution Ser434-Ala of pTAC10. These data show that pTAC10 is essential for plastid gene expression in Arabidopsis and that it can be phosphorylated by cpCK2.
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Affiliation(s)
- Qing-Bo Yu
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Tuan-Tuan Zhao
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Lin-Shan Ye
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Ling Cheng
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Ying-Qian Wu
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Chao Huang
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Zhong-Nan Yang
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 200234, China.
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7
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White-Gloria C, Johnson JJ, Marritt K, Kataya A, Vahab A, Moorhead GB. Protein Kinases and Phosphatases of the Plastid and Their Potential Role in Starch Metabolism. FRONTIERS IN PLANT SCIENCE 2018; 9:1032. [PMID: 30065742 PMCID: PMC6056723 DOI: 10.3389/fpls.2018.01032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/25/2018] [Indexed: 05/03/2023]
Abstract
Phospho-proteomic studies have confirmed that phosphorylation is a common mechanism to regulate protein function in the chloroplast, including the enzymes of starch metabolism. In addition to the photosynthetic machinery protein kinases (STN7 and STN8) and their cognate protein phosphatases PPH1 (TAP38) and PBCP, multiple other protein kinases and phosphatases have now been localized to the chloroplast. Here, we build a framework for understanding protein kinases and phosphatases, their regulation, and potential roles in starch metabolism. We also catalog mapped phosphorylation sites on proteins of chloroplast starch metabolism to illustrate the potential and mostly unknown roles of protein phosphorylation in the regulation of starch biology.
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Affiliation(s)
- Chris White-Gloria
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Jayde J. Johnson
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Kayla Marritt
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Amr Kataya
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
- Department of Chemistry and Biosciences, University of Stavanger, Stavanger, Norway
| | - Ahmad Vahab
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Greg B. Moorhead
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
- *Correspondence: Greg B. Moorhead,
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8
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Schönberg A, Rödiger A, Mehwald W, Galonska J, Christ G, Helm S, Thieme D, Majovsky P, Hoehenwarter W, Baginsky S. Identification of STN7/STN8 kinase targets reveals connections between electron transport, metabolism and gene expression. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 90:1176-1186. [PMID: 28295753 DOI: 10.1111/tpj.13536] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/03/2017] [Accepted: 03/06/2017] [Indexed: 05/18/2023]
Abstract
The thylakoid-associated kinases STN7 and STN8 are involved in short- and long-term acclimation of photosynthetic electron transport to changing light conditions. Here we report the identification of STN7/STN8 in vivo targets that connect photosynthetic electron transport with metabolism and gene expression. Comparative phosphoproteomics with the stn7 and stn8 single and double mutants identified two proteases, one RNA-binding protein, a ribosomal protein, the large subunit of Rubisco and a ferredoxin-NADP reductase as targets for the thylakoid-associated kinases. Phosphorylation of three of the above proteins can be partially complemented by STN8 in the stn7 single mutant, albeit at lower efficiency, while phosphorylation of the remaining three proteins strictly depends on STN7. The properties of the STN7-dependent phosphorylation site are similar to those of phosphorylated light-harvesting complex proteins entailing glycine or another small hydrophobic amino acid in the -1 position. Our analysis uncovers the STN7/STN8 kinases as mediators between photosynthetic electron transport, its immediate downstream sinks and long-term adaptation processes affecting metabolite accumulation and gene expression.
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Affiliation(s)
- Anna Schönberg
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Anja Rödiger
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Wiebke Mehwald
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Johann Galonska
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Gideon Christ
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Stefan Helm
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Domenika Thieme
- Proteomeanalytik, Leibniz Institute of Plant Biochemistry, Halle (Saale), Germany
| | - Petra Majovsky
- Proteomeanalytik, Leibniz Institute of Plant Biochemistry, Halle (Saale), Germany
| | | | - Sacha Baginsky
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
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9
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Richter AS, Hochheuser C, Fufezan C, Heinze L, Kuhnert F, Grimm B. Phosphorylation of GENOMES UNCOUPLED 4 Alters Stimulation of Mg Chelatase Activity in Angiosperms. PLANT PHYSIOLOGY 2016; 172:1578-1595. [PMID: 27688621 PMCID: PMC5100749 DOI: 10.1104/pp.16.01036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/27/2016] [Indexed: 05/07/2023]
Abstract
GENOMES UNCOUPLED 4 (GUN4) is a positive regulator of light-dependent chlorophyll biosynthesis. GUN4 activates Mg chelatase (MgCh) that catalyzes the insertion of an Mg2+ ion into protoporphyrin IX. We show that Arabidopsis (Arabidopsis thaliana) GUN4 is phosphorylated at Ser 264 (S264), the penultimate amino acid residue at the C terminus. While GUN4 is preferentially phosphorylated in darkness, phosphorylation is reduced upon accumulation of Mg porphyrins. Expression of a phosphomimicking GUN4(S264D) results in an incomplete complementation of the white gun4-2 null mutant and a chlorotic phenotype comparable to gun4 knockdown mutants. Phosphorylated GUN4 has a reduced stimulatory effect on MgCh in vitro and in vivo but retains its protein stability and tetrapyrrole binding capacity. Analysis of GUN4 found in oxygenic photosynthetic organisms reveals the evolution of a C-terminal extension, which harbors the phosphorylation site of GUN4 expressed in angiosperms. Homologs of GUN4 from Synechocystis and Chlamydomonas lack the conserved phosphorylation site found in a C-terminal extension of angiosperm GUN4. Biochemical studies proved the importance of the C-terminal extension for MgCh stimulation and inactivation of GUN4 by phosphorylation in angiosperms. An additional mechanism regulating MgCh activity is proposed. In conjunction with the dark repression of 5-aminolevulinic acid synthesis, GUN4 phosphorylation minimizes the flow of intermediates into the Mg branch of the tetrapyrrole metabolic pathway for chlorophyll biosynthesis.
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Affiliation(s)
- Andreas Sven Richter
- Plant Physiology, Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany (A.S.R., C.H., L.H., F.K., B.G.); and
- Computational Biology, Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany (C.F.)
| | - Caroline Hochheuser
- Plant Physiology, Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany (A.S.R., C.H., L.H., F.K., B.G.); and
- Computational Biology, Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany (C.F.)
| | - Christian Fufezan
- Plant Physiology, Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany (A.S.R., C.H., L.H., F.K., B.G.); and
- Computational Biology, Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany (C.F.)
| | - Laura Heinze
- Plant Physiology, Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany (A.S.R., C.H., L.H., F.K., B.G.); and
- Computational Biology, Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany (C.F.)
| | - Franziska Kuhnert
- Plant Physiology, Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany (A.S.R., C.H., L.H., F.K., B.G.); and
- Computational Biology, Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany (C.F.)
| | - Bernhard Grimm
- Plant Physiology, Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany (A.S.R., C.H., L.H., F.K., B.G.); and
- Computational Biology, Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany (C.F.)
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10
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Lohscheider JN, Friso G, van Wijk KJ. Phosphorylation of plastoglobular proteins in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3975-84. [PMID: 26962209 PMCID: PMC4915526 DOI: 10.1093/jxb/erw091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Plastoglobules (PGs) are plastid lipid-protein particles with a small specialized proteome and metabolome. Among the 30 core PG proteins are six proteins of the ancient ABC1 atypical kinase (ABC1K) family and their locations in an Arabidopsis mRNA-based co-expression network suggested central regulatory roles. To identify candidate ABC1K targets and a possible ABC1K hierarchical phosphorylation network within the chloroplast PG proteome, we searched Arabidopsis phosphoproteomics data from publicly available sources. Evaluation of underlying spectra and/or associated information was challenging for a variety of reasons, but supported pSer sites and a few pThr sites in nine PG proteins, including five FIBRILLINS. PG phosphorylation motifs are discussed in the context of possible responsible kinases. The challenges of collection and evaluation of published Arabidopsis phosphorylation data are discussed, illustrating the importance of deposition of all mass spectrometry data in well-organized repositories such as PRIDE and ProteomeXchange. This study provides a starting point for experimental testing of phosho-sites in PG proteins and also suggests that phosphoproteomics studies specifically designed toward the PG proteome and its ABC1K are needed to understand phosphorylation networks in these specialized particles.
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Affiliation(s)
- Jens N Lohscheider
- Section of Plant Biology, School of Integrated Plant Science (SIPS), Cornell University, Ithaca, NY 14853, USA
| | - Giulia Friso
- Section of Plant Biology, School of Integrated Plant Science (SIPS), Cornell University, Ithaca, NY 14853, USA
| | - Klaas J van Wijk
- Section of Plant Biology, School of Integrated Plant Science (SIPS), Cornell University, Ithaca, NY 14853, USA
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11
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Richter AS, Gartmann H, Fechler M, Rödiger A, Baginsky S, Grimm B. Identification of four plastid-localized protein kinases. FEBS Lett 2016; 590:1749-56. [PMID: 27214872 DOI: 10.1002/1873-3468.12223] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 05/17/2016] [Accepted: 05/18/2016] [Indexed: 12/16/2023]
Abstract
In chloroplasts, protein phosphorylation regulates important processes, including metabolism, photosynthesis, gene expression, and signaling. Because the hitherto known plastid protein kinases represent only a fraction of existing kinases, we aimed at the identification of novel plastid-localized protein kinases that potentially phosphorylate enzymes of the tetrapyrrole biosynthesis (TBS) pathway. We screened publicly available databases for proteins annotated as putative protein kinase family proteins with predicted chloroplast localization. Additionally, we analyzed chloroplast fractions which were separated by sucrose density gradient centrifugation by mass spectrometry. We identified four new candidates for protein kinases, which were confirmed to be plastid localized by expression of GFP-fusion proteins in tobacco leaves. A phosphorylation assay with the purified kinases confirmed the protein kinase activity for two of them.
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Affiliation(s)
- Andreas S Richter
- Humboldt Universität zu Berlin, Institute of Biology/Plant Physiology, Berlin, Germany
| | - Hans Gartmann
- Humboldt Universität zu Berlin, Institute of Biology/Plant Physiology, Berlin, Germany
| | - Mona Fechler
- Humboldt Universität zu Berlin, Institute of Biology/Plant Physiology, Berlin, Germany
| | - Anja Rödiger
- Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Sacha Baginsky
- Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Bernhard Grimm
- Humboldt Universität zu Berlin, Institute of Biology/Plant Physiology, Berlin, Germany
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12
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Baginsky S. Protein phosphorylation in chloroplasts - a survey of phosphorylation targets. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3873-82. [PMID: 26969742 DOI: 10.1093/jxb/erw098] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The development of new software tools, improved mass spectrometry equipment, a suite of optimized scan types, and better-quality phosphopeptide affinity capture have paved the way for an explosion of mass spectrometry data on phosphopeptides. Because phosphoproteomics achieves good sensitivity, most studies use complete cell extracts for phosphopeptide enrichment and identification without prior enrichment of proteins or subcellular compartments. As a consequence, the phosphoproteome of cell organelles often comes as a by-product from large-scale studies and is commonly assembled from these in meta-analyses. This review aims at providing some guidance on the limitations of meta-analyses that combine data from analyses with different scopes, reports on the current status of knowledge on chloroplast phosphorylation targets, provides initial insights into phosphorylation site conservation in different plant species, and highlights emerging information on the integration of gene expression with metabolism and photosynthesis by means of protein phosphorylation.
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Affiliation(s)
- Sacha Baginsky
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Weinbergweg 22, 06120 Halle (Saale), Germany
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Kim SY, Bender KW, Walker BJ, Zielinski RE, Spalding MH, Ort DR, Huber SC. The Plastid Casein Kinase 2 Phosphorylates Rubisco Activase at the Thr-78 Site but Is Not Essential for Regulation of Rubisco Activation State. FRONTIERS IN PLANT SCIENCE 2016; 7:404. [PMID: 27064346 PMCID: PMC4814456 DOI: 10.3389/fpls.2016.00404] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 03/16/2016] [Indexed: 05/05/2023]
Abstract
Rubisco activase (RCA) is essential for the activation of Rubisco, the carboxylating enzyme of photosynthesis. In Arabidopsis, RCA is composed of a large RCAα and small RCAβ isoform that are formed by alternative splicing of a single gene (At2g39730). The activity of Rubisco is controlled in response to changes in irradiance by regulation of RCA activity, which is known to involve a redox-sensitive disulfide bond located in the carboxy-terminal extension of the RCAα subunit. Additionally, phosphorylation of RCA threonine-78 (Thr-78) has been reported to occur in the dark suggesting that phosphorylation may also be associated with dark-inactivation of RCA and deactivation of Rubisco. In the present study, we developed site-specific antibodies to monitor phosphorylation of RCA at the Thr-78 site and used non-reducing SDS-PAGE to monitor the redox status of the RCAα subunit. By immunoblotting, phosphorylation of both RCA isoforms occurred at low light and in the dark and feeding peroxide or DTT to leaf segments indicated that redox status of the chloroplast stroma was a critical factor controlling RCA phosphorylation. Use of a knockout mutant identified the plastid-targeted casein kinase 2 (cpCK2α) as the major protein kinase involved in RCA phosphorylation. Studies with recombinant cpCK2α and synthetic peptide substrates identified acidic residues at the -1, +2, and +3 positions surrounding Thr-78 as strong positive recognition elements. The cpck2 knockout mutant had strongly reduced phosphorylation at the Thr-78 site but was similar to wild type plants in terms of induction kinetics of photosynthesis following transfer from darkness or low light to high light, suggesting that if phosphorylation of RCA Thr-78 plays a direct role it would be redundant to redox regulation for control of Rubisco activation state under normal conditions.
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Affiliation(s)
- Sang Y. Kim
- Global Change and Photosynthesis Research Unit, United States Department of Agriculture – Agricultural Research Service, UrbanaIL, USA
- Plant Biology, University of Illinois at Champaign–Urbana, UrbanaIL, USA
| | - Kyle W. Bender
- Plant Biology, University of Illinois at Champaign–Urbana, UrbanaIL, USA
| | - Berkley J. Walker
- Global Change and Photosynthesis Research Unit, United States Department of Agriculture – Agricultural Research Service, UrbanaIL, USA
- Carl R. Woese Institute for Genomic Biology, UrbanaIL, USA
| | | | - Martin H. Spalding
- Genetics, Development and Cell Biology, Iowa State University, AmesIA, USA
| | - Donald R. Ort
- Global Change and Photosynthesis Research Unit, United States Department of Agriculture – Agricultural Research Service, UrbanaIL, USA
- Plant Biology, University of Illinois at Champaign–Urbana, UrbanaIL, USA
- Carl R. Woese Institute for Genomic Biology, UrbanaIL, USA
| | - Steven C. Huber
- Global Change and Photosynthesis Research Unit, United States Department of Agriculture – Agricultural Research Service, UrbanaIL, USA
- Plant Biology, University of Illinois at Champaign–Urbana, UrbanaIL, USA
- *Correspondence: Steven C. Huber,
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Urbischek M, Nick von Braun S, Brylok T, Gügel IL, Richter A, Koskela M, Grimm B, Mulo P, Bölter B, Soll J, Ankele E, Schwenkert S. The extreme Albino3 (Alb3) C terminus is required for Alb3 stability and function in Arabidopsis thaliana. PLANTA 2015; 242:733-746. [PMID: 26105652 DOI: 10.1007/s00425-015-2352-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 06/11/2015] [Indexed: 05/28/2023]
Abstract
The extreme Alb3 C terminus is important for Alb3 stability in a light dependent manner, but is dispensable for LHCP insertion or D1 synthesis. YidC/Oxa1/Alb3 dependent insertion of membrane proteins is evolutionary conserved among bacteria, mitochondria and chloroplasts. Chloroplasts are challenged by the need to coordinate membrane integration of nuclear encoded, post-translationally targeted proteins into the thylakoids as well as of proteins translated on plastid ribosomes. The pathway facilitating post-translational targeting of the light-harvesting chlorophyll a/b binding proteins involves the chloroplast signal recognition particle, cpSRP54 and cpSRP43, as well as its membrane receptor FtsY and the translocase Alb3. Interaction of cpSRP43 with Alb3 is mediated by the positively charged, stromal exposed C terminus of Alb3. In this study, we utilized an Alb3 T-DNA insertion mutant in Arabidopsis thaliana lacking the last 75 amino acids to elucidate the function of this domain (alb3∆C). However, the truncated Alb3 protein (Alb3∆C) proved to be unstable under standard growth conditions, resulting in a reduction of Alb3∆C to 20 % of wild-type levels. In contrast, accumulation of Alb3∆C was comparable to wild type under low light growth conditions. Alb3∆C mutants grown under low light conditions were only slightly paler than wild type, accumulated almost wild-type levels of light harvesting proteins and were not affected in D1 synthesis, therefore showing that the extreme Alb3 C terminus is dispensable for both, co- and post-translational, protein insertion into the thylakoid membrane. However, reduction of Alb3∆C levels as observed under standard growth conditions resulted not only in a severely diminished accumulation of all thylakoid complexes but also in a strong defect in D1 synthesis and membrane insertion.
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Affiliation(s)
- Manuela Urbischek
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse. 2-4, 82152, Planegg-Martinsried, Germany
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Rohe A, Platzer C, Masch A, Greiner S, Henze C, Ihling C, Erdmann F, Schutkowski M, Sippl W, Schmidt M. Identification of peptidic substrates for the human kinase Myt1 using peptide microarrays. Bioorg Med Chem 2015; 23:4936-4942. [DOI: 10.1016/j.bmc.2015.05.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 01/25/2023]
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Regulation and function of tetrapyrrole biosynthesis in plants and algae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:968-85. [PMID: 25979235 DOI: 10.1016/j.bbabio.2015.05.007] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/21/2015] [Accepted: 05/07/2015] [Indexed: 12/20/2022]
Abstract
Tetrapyrroles are macrocyclic molecules with various structural variants and multiple functions in Prokaryotes and Eukaryotes. Present knowledge about the metabolism of tetrapyrroles reflects the complex evolution of the pathway in different kingdoms of organisms, the complexity of structural and enzymatic variations of enzymatic steps, as well as a wide range of regulatory mechanisms, which ensure adequate synthesis of tetrapyrrole end-products at any time of development and environmental condition. This review intends to highlight new findings of research on tetrapyrrole biosynthesis in plants and algae. In the course of the heme and chlorophyll synthesis in these photosynthetic organisms, glutamate, one of the central and abundant metabolites, is converted into highly photoreactive tetrapyrrole intermediates. Thereby, several mechanisms of posttranslational control are thought to be essential for a tight regulation of each enzymatic step. Finally, we wish to discuss the potential role of tetrapyrroles in retrograde signaling and point out perspectives of the formation of macromolecular protein complexes in tetrapyrrole biosynthesis as an efficient mechanism to ensure a fine-tuned metabolic flow in the pathway. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Vilela B, Pagès M, Riera M. Emerging roles of protein kinase CK2 in abscisic acid signaling. FRONTIERS IN PLANT SCIENCE 2015; 6:966. [PMID: 26579189 PMCID: PMC4630567 DOI: 10.3389/fpls.2015.00966] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 10/22/2015] [Indexed: 05/02/2023]
Abstract
The phytohormone abscisic acid (ABA) regulates many aspects of plant growth and development as well as responses to multiple stresses. Post-translational modifications such as phosphorylation or ubiquitination have pivotal roles in the regulation of ABA signaling. In addition to the positive regulator sucrose non-fermenting-1 related protein kinase 2 (SnRK2), the relevance of the role of other protein kinases, such as CK2, has been recently highlighted. We have recently established that CK2 phosphorylates the maize ortholog of open stomata 1 OST1, ZmOST1, suggesting a role of CK2 phosphorylation in the control of ZmOST1 protein degradation (Vilela et al., 2015). CK2 is a pleiotropic enzyme involved in multiple developmental and stress-responsive pathways. This review summarizes recent advances that taken together suggest a prominent role of protein kinase CK2 in ABA signaling and related processes.
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