1
|
Espinoza‐Corral R, Schwenkert S, Schneider A. Characterization of the preferred cation cofactors of chloroplast protein kinases in Arabidopsis thaliana. FEBS Open Bio 2023; 13:511-518. [PMID: 36683405 PMCID: PMC9989932 DOI: 10.1002/2211-5463.13563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/09/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
Chloroplasts sense a variety of stimuli triggering several acclimation responses. One prominent response is the mechanism of state transitions, which enables rapid adaption to changes in illumination. Here, we investigated the link between divalent cations (calcium, magnesium, and manganese) and protein kinase activity in Arabidopsis chloroplasts. Our results show that manganese ions are the strongest activator of kinase activity in chloroplasts followed by magnesium ions, whereas calcium ions are not able to induce kinase activity. Additionally, the phosphorylation of specific protein bands is strongly reduced in chloroplasts of a cmt1 mutant, which is impaired in manganese import into chloroplasts, as compared to the wild-type. These findings provide insights for the future characterization of chloroplast protein kinase activity and potential target proteins.
Collapse
Affiliation(s)
| | - Serena Schwenkert
- Plant Molecular Biology, Faculty of BiologyLudwig Maximilians University MunichPlaneggGermany
| | - Anja Schneider
- Plant Molecular Biology, Faculty of BiologyLudwig Maximilians University MunichPlaneggGermany
| |
Collapse
|
2
|
Pseudophosphorylation of Arabidopsis jasmonate biosynthesis enzyme lipoxygenase 2 via mutation of Ser 600 inhibits enzyme activity. J Biol Chem 2023; 299:102898. [PMID: 36639029 PMCID: PMC9947334 DOI: 10.1016/j.jbc.2023.102898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/07/2023] [Accepted: 01/09/2023] [Indexed: 01/12/2023] Open
Abstract
Jasmonates are oxylipin phytohormones critical for plant resistance against necrotrophic pathogens and chewing herbivores. An early step in their biosynthesis is catalyzed by non-heme iron lipoxygenases (LOX; EC 1.13.11.12). In Arabidopsis thaliana, phosphorylation of Ser600 of AtLOX2 was previously reported, but whether phosphorylation regulates AtLOX2 activity is unclear. Here, we characterize the kinetic properties of recombinant WT AtLOX2 (AtLOX2WT). AtLOX2WT displays positive cooperativity with α-linolenic acid (α-LeA, jasmonate precursor), linoleic acid (LA), and arachidonic acid (AA) as substrates. Enzyme velocity with endogenous substrates α-LeA and LA increased with pH. For α-LeA, this increase was accompanied by a decrease in substrate affinity at alkaline pH; thus, the catalytic efficiency for α-LeA was not affected over the pH range tested. Analysis of Ser600 phosphovariants demonstrated that pseudophosphorylation inhibits enzyme activity. AtLOX2 activity was not detected in phosphomimics Atlox2S600D and Atlox2S600M when α-LeA or AA were used as substrates. In contrast, phosphonull mutant Atlox2S600A exhibited strong activity with all three substrates, α-LeA, LA, and AA. Structural comparison between the AtLOX2 AlphaFold model and a complex between 8R-LOX and a 20C polyunsaturated fatty acid suggests a close proximity between AtLOX2 Ser600 and the carboxylic acid head group of the polyunsaturated fatty acid. This analysis indicates that Ser600 is located at a critical position within the AtLOX2 structure and highlights how Ser600 phosphorylation could affect AtLOX2 catalytic activity. Overall, we propose that AtLOX2 Ser600 phosphorylation represents a key mechanism for the regulation of AtLOX2 activity and, thus, the jasmonate biosynthesis pathway and plant resistance.
Collapse
|
3
|
Spät P, Barske T, Maček B, Hagemann M. Alterations in the CO 2 availability induce alterations in the phosphoproteome of the cyanobacterium Synechocystis sp. PCC 6803. THE NEW PHYTOLOGIST 2021; 231:1123-1137. [PMID: 34058021 DOI: 10.1111/nph.17423] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 04/16/2021] [Indexed: 06/12/2023]
Abstract
Cyanobacteria are the only prokaryotes that perform plant-like oxygenic photosynthesis. They evolved an inorganic carbon-concentrating mechanism to adapt to low CO2 conditions. Quantitative phosphoproteomics was applied to analyze regulatory features during the acclimation to low CO2 conditions in the model cyanobacterium Synechocystis sp. PCC 6803. Overall, more than 2500 proteins were quantified, equivalent to c. 70% of the Synechocystis theoretical proteome. Proteins with changing abundances correlated largely with mRNA expression levels. Functional annotation of the noncorrelating proteins revealed an enrichment of key metabolic processes fundamental for maintaining cellular homeostasis. Furthermore, 105 phosphoproteins harboring over 200 site-specific phosphorylation events were identified. Subunits of the bicarbonate transporter BCT1 and the redox switch protein CP12 were among phosphoproteins with reduced phosphorylation levels at lower CO2 , whereas the serine/threonine protein kinase SpkC revealed increased phosphorylation levels. The corresponding ΔspkC mutant was characterized and showed decreased ability to acclimate to low CO2 conditions. Possible phosphorylation targets of SpkC including a BCT1 subunit were identified by phosphoproteomics. Collectively, our study highlights the importance of posttranscriptional regulation of protein abundances as well as posttranslational regulation by protein phosphorylation for the successful acclimation towards low CO2 conditions in Synechocystis and possibly among cyanobacteria.
Collapse
Affiliation(s)
- Philipp Spät
- Department of Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, D-72076, Germany
- Department of Quantitative Proteomics, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, D-72076, Germany
| | - Thomas Barske
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, D-18059, Germany
| | - Boris Maček
- Department of Quantitative Proteomics, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, D-72076, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, D-18059, Germany
- Department Life, Light and Matter, Interdisciplinary Faculty, University of Rostock, Rostock, D-18059, Germany
| |
Collapse
|
4
|
Espinoza-Corral R, Schwenkert S, Lundquist PK. Molecular changes of Arabidopsis thaliana plastoglobules facilitate thylakoid membrane remodeling under high light stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:1571-1587. [PMID: 33783866 DOI: 10.1111/tpj.15253] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/14/2021] [Accepted: 03/18/2021] [Indexed: 05/21/2023]
Abstract
Plants require rapid responses to adapt to environmental stresses. This includes dramatic changes in the size and number of plastoglobule lipid droplets within chloroplasts. Although the morphological changes of plastoglobules are well documented, little is known about the corresponding molecular changes. To address this gap, we have compared the quantitative proteome, oligomeric state, prenyl-lipid content and kinase activities of Arabidopsis thaliana plastoglobules under unstressed and 5-day light-stressed conditions. Our results show a specific recruitment of proteins related to leaf senescence and jasmonic acid biosynthesis under light stress, and identify nearly half of the plastoglobule proteins in high native molecular weight masses. Additionally, a specific increase in plastoglobule carotenoid abundance under the light stress was consistent with enhanced thylakoid disassembly and leaf senescence, supporting a specific role for plastoglobules in senescence and thylakoid remodeling as an intermediate storage site for photosynthetic pigments. In vitro kinase assays of isolated plastoglobules demonstrated kinase activity towards multiple target proteins, which was more pronounced in the plastoglobules of unstressed than light-stressed leaf tissue, and which was diminished in plastoglobules of the abc1k1/abc1k3 double-mutant. These results strongly suggest that plastoglobule-localized ABC1 kinases hold endogenous kinase activity, as these were the only known or putative kinases identified in the isolated plastoglobules by deep bottom-up proteomics. Collectively, our study reveals targeted changes to the protein and prenyl-lipid composition of plastoglobules under light stress that present strategies by which plastoglobules appear to facilitate stress adaptation within chloroplasts.
Collapse
Affiliation(s)
- Roberto Espinoza-Corral
- Department of Biochemistry and Molecular Biology, Plant Resilience Institute, Michigan State University, East Lansing, MI, USA
| | - Serena Schwenkert
- Department I, Plant Biochemistry, Ludwig Maximilians University Munich, Großhadernerstr. 2-4, Planegg-Martinsried, 82152, Germany
| | - Peter K Lundquist
- Department of Biochemistry and Molecular Biology, Plant Resilience Institute, Michigan State University, East Lansing, MI, USA
| |
Collapse
|
5
|
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.
Collapse
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,
| |
Collapse
|
6
|
van Wijk KJ, Kessler F. Plastoglobuli: Plastid Microcompartments with Integrated Functions in Metabolism, Plastid Developmental Transitions, and Environmental Adaptation. ANNUAL REVIEW OF PLANT BIOLOGY 2017; 68:253-289. [PMID: 28125283 DOI: 10.1146/annurev-arplant-043015-111737] [Citation(s) in RCA: 170] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plastoglobuli (PGs) are plastid lipoprotein particles surrounded by a membrane lipid monolayer. PGs contain small specialized proteomes and metabolomes. They are present in different plastid types (e.g., chloroplasts, chromoplasts, and elaioplasts) and are dynamic in size and shape in response to abiotic stress or developmental transitions. PGs in chromoplasts are highly enriched in carotenoid esters and enzymes involved in carotenoid metabolism. PGs in chloroplasts are associated with thylakoids and contain ∼30 core proteins (including six ABC1 kinases) as well as additional proteins recruited under specific conditions. Systems analysis has suggested that chloroplast PGs function in metabolism of prenyl lipids (e.g., tocopherols, plastoquinone, and phylloquinone); redox and photosynthetic regulation; plastid biogenesis; and senescence, including recycling of phytol, remobilization of thylakoid lipids, and metabolism of jasmonate. These functionalities contribute to chloroplast PGs' role in responses to stresses such as high light and nitrogen starvation. PGs are thus lipid microcompartments with multiple functions integrated into plastid metabolism, developmental transitions, and environmental adaptation. This review provides an in-depth overview of PG experimental observations, summarizes the present understanding of PG features and functions, and provides a conceptual framework for PG research and the realization of opportunities for crop improvement.
Collapse
Affiliation(s)
- Klaas J van Wijk
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853;
| | - Felix Kessler
- Laboratory of Plant Physiology, University of Neuchâtel, 2000 Neuchâtel, Switzerland;
| |
Collapse
|