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Yamamoto N, Xiang G, Tong W, Lv B, Guo Y, Wu Y, Peng Z, Yang Z. Over-expression of a plant-type phosphoenolpyruvate carboxylase derails Arabidopsis stamen formation. Gene 2024; 927:148749. [PMID: 38969247 DOI: 10.1016/j.gene.2024.148749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 06/26/2024] [Accepted: 07/02/2024] [Indexed: 07/07/2024]
Abstract
We examined whether plant-type phosphoenolpyruvate carboxylase (PEPC) is involved in flower organ formation or not by over-expression in Arabidopsis. A wheat PEPC isogene Tappc3A, belonging to the ppc3 group, was targeted due to its preferential expression pattern in pistils and stamens. Transgenic Arabidopsis over-expressing Tappc3A exhibited irregular stamen formation, i.e., a lesser number of stamens per flower and shorter filaments in T2 and T3 generations. Irregular stamens were frequently observed in homozygous T4 lines, but no morphological change was observed in other floral organs. High-degree gene co-expression of Tappc3 isogenes with wheat SEEDSTICKs but not with other homeotic transcription factor genes for flower formation implicates that Tappc3 is under control by the class D genes of the ABCDE model to flower development. In addition, the conservation of CArG box sequences on the Tappc3 promoters supported the developmentally programmed gene expression of ppc3 in wheat flowering organs. Thus, this study provides the first experimental evidence for the critical regulation of plant-type PEPC for flower formation.
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Affiliation(s)
- Naoki Yamamoto
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), College of Life Science, China West Normal University, Nanchong, China
| | - Guili Xiang
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), College of Life Science, China West Normal University, Nanchong, China
| | - Wurina Tong
- College of Environmental Science and Engineering, China West Normal University, Nanchong, China
| | - Bingbing Lv
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), College of Life Science, China West Normal University, Nanchong, China
| | - Yuhuan Guo
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), College of Life Science, China West Normal University, Nanchong, China
| | - Yichao Wu
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), College of Life Science, China West Normal University, Nanchong, China
| | - Zhengsong Peng
- School of Agricultural Science, Xichang College, Xichang, China
| | - Zaijun Yang
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), College of Life Science, China West Normal University, Nanchong, China.
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Zhang X, Bai L, Li M, Li Y, Hu R, Guo H. Pollen transcriptomic analysis provided insights into understanding the molecular mechanisms underlying grafting-induced improvement in potato fertility. FRONTIERS IN PLANT SCIENCE 2024; 15:1338106. [PMID: 38606064 PMCID: PMC11007164 DOI: 10.3389/fpls.2024.1338106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 02/05/2024] [Indexed: 04/13/2024]
Abstract
Introduction Heterologous grafting has been proven to be a valid approach to improving potato fertility, especially when grafting potatoes with other Solanaceae family plants. However, the mechanisms underlying grafting-induced improvement in potato fertility are still unknown. Methods In this study, a poor-fertility potato cultivar "Qingshu No. 9" (Q9) was grafted with a tomato cultivar "Zhongyan988" (ZY988) to study the effects of heterologous grafting in the former. The tuber yield was controlled by different grafting and cultivation approaches, and the correlation between tuber yield and pollen vigor was studied. Comparative transcriptomic analysis of the potential mechanisms of pollen in potato scion fertility changes. Result Grafting with the tomato rootstock effectively promoted the flower and fruit formation in the scion potato and improved its pollen viability by 15%-20%. In addition, a significant negative correlation was observed between the potato tuber yield and pollen viability, suggesting a potential impact on the metabolic regulatory network related to tuber formation. From the comparative transcriptomic analysis between the pollens from Q9 self-grafted plants and Q9-tomato grafting scion, 513 differentially expressed genes (DEGs) were identified. These DEGs were found to be related to gametophyte and pollen development, carbohydrate metabolism, and protein processing. Thus, these DEGs might be involved in improved fertility after reduced tuberization in plants subjected to heterologous grafting. Discussion Potato/tomato heterologous grafting significantly improved the pollen viability of scion potatoes and was associated with the absence of potato tubers. Heterologous grafting promotes the transcription of genes related to protein processing, carbohydrate metabolism, and pollen development in pollen cells, resulting in the production of fertile pollen. Our results provided initial clues to understanding the improvement of potato fertility using the heterologous grafting method, which might be a useful tool in assisted potato breeding.
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Affiliation(s)
- Xing Zhang
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Engineering Research Center of Tuber and Root Crop Bio-breeding and Healthy Seed Propagation, Yunnan Agricultural University, Kunming, Yunnan, China
- Tuber and Root Crops Research Institute, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Lei Bai
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Engineering Research Center of Tuber and Root Crop Bio-breeding and Healthy Seed Propagation, Yunnan Agricultural University, Kunming, Yunnan, China
- Tuber and Root Crops Research Institute, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Maoxing Li
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Engineering Research Center of Tuber and Root Crop Bio-breeding and Healthy Seed Propagation, Yunnan Agricultural University, Kunming, Yunnan, China
- Tuber and Root Crops Research Institute, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Youhan Li
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Engineering Research Center of Tuber and Root Crop Bio-breeding and Healthy Seed Propagation, Yunnan Agricultural University, Kunming, Yunnan, China
- Tuber and Root Crops Research Institute, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Ronghai Hu
- Technical Department, Yunnan BengLong Potato Planting Co., Ltd, Kunming, Yunnan, China
| | - Huachun Guo
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Engineering Research Center of Tuber and Root Crop Bio-breeding and Healthy Seed Propagation, Yunnan Agricultural University, Kunming, Yunnan, China
- Tuber and Root Crops Research Institute, Yunnan Agricultural University, Kunming, Yunnan, China
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Li R, Gao X, Wu Y, Wei C, Li MH, Liu DK, Liu ZJ. Identification and Analysis of PEPC Gene Family Reveals Functional Diversification in Orchidaceae and the Regulation of Bacterial-Type PEPC. Int J Mol Sci 2024; 25:2055. [PMID: 38396732 PMCID: PMC10888551 DOI: 10.3390/ijms25042055] [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: 12/05/2023] [Revised: 01/29/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Phosphoenolpyruvate carboxylase (PEPC) gene family plays a crucial role in both plant growth and response to abiotic stress. Approximately half of the Orchidaceae species are estimated to perform CAM pathway, and the availability of sequenced orchid genomes makes them ideal subjects for investigating the PEPC gene family in CAM plants. In this study, a total of 33 PEPC genes were identified across 15 orchids. Specifically, one PEPC gene was found in Cymbidium goeringii and Platanthera guangdongensis; two in Apostasia shenzhenica, Dendrobium chrysotoxum, D. huoshanense, Gastrodia elata, G. menghaiensis, Phalaenopsis aphrodite, Ph. equestris, and Pl. zijinensis; three in C. ensifolium, C. sinense, D. catenatum, D. nobile, and Vanilla planifolia. These PEPC genes were categorized into four subgroups, namely PEPC-i, PEPC-ii, and PEPC-iii (PTPC), and PEPC-iv (BTPC), supported by the comprehensive analyses of their physicochemical properties, motif, and gene structures. Remarkably, PEPC-iv contained a heretofore unreported orchid PEPC gene, identified as VpPEPC4. Differences in the number of PEPC homolog genes among these species were attributed to segmental duplication, whole-genome duplication (WGD), or gene loss events. Cis-elements identified in promoter regions were predominantly associated with light responsiveness, and circadian-related elements were observed in each PEPC-i and PEPC-ii gene. The expression levels of recruited BTPC, VpPEPC4, exhibited a lower expression level than other VpPEPCs in the tested tissues. The expression analyses and RT-qPCR results revealed diverse expression patterns in orchid PEPC genes. Duplicated genes exhibited distinct expression patterns, suggesting functional divergence. This study offered a comprehensive analysis to unveil the evolution and function of PEPC genes in Orchidaceae.
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Affiliation(s)
- Ruyi Li
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at Landscape Architecture and Arts, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (R.L.); (X.G.); (Y.W.); (C.W.); (M.-H.L.)
| | - Xuyong Gao
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at Landscape Architecture and Arts, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (R.L.); (X.G.); (Y.W.); (C.W.); (M.-H.L.)
| | - Yuwei Wu
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at Landscape Architecture and Arts, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (R.L.); (X.G.); (Y.W.); (C.W.); (M.-H.L.)
| | - Chunyi Wei
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at Landscape Architecture and Arts, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (R.L.); (X.G.); (Y.W.); (C.W.); (M.-H.L.)
| | - Ming-He Li
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at Landscape Architecture and Arts, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (R.L.); (X.G.); (Y.W.); (C.W.); (M.-H.L.)
- Fujian Colleges and Universities Engineering Research Institute of Conservation and Utilization of Natural Bioresources, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ding-Kun Liu
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at Landscape Architecture and Arts, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (R.L.); (X.G.); (Y.W.); (C.W.); (M.-H.L.)
- Fujian Colleges and Universities Engineering Research Institute of Conservation and Utilization of Natural Bioresources, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zhong-Jian Liu
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at Landscape Architecture and Arts, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (R.L.); (X.G.); (Y.W.); (C.W.); (M.-H.L.)
- Fujian Colleges and Universities Engineering Research Institute of Conservation and Utilization of Natural Bioresources, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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Liu J, Lim SL, Zhong JY, Lim BL. Bioenergetics of pollen tube growth in Arabidopsis thaliana revealed by ratiometric genetically encoded biosensors. Nat Commun 2022; 13:7822. [PMID: 36535933 PMCID: PMC9763403 DOI: 10.1038/s41467-022-35486-w] [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: 06/03/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
Pollen tube is the fastest-growing plant cell. Its polarized growth process consumes a tremendous amount of energy, which involves coordinated energy fluxes between plastids, the cytosol, and mitochondria. However, how the pollen tube obtains energy and what the biological roles of pollen plastids are in this process remain obscure. To investigate this energy-demanding process, we developed second-generation ratiometric biosensors for pyridine nucleotides which are pH insensitive between pH 7.0 to pH 8.5. By monitoring dynamic changes in ATP and NADPH concentrations and the NADH/NAD+ ratio at the subcellular level in Arabidopsis (Arabidopsis thaliana) pollen tubes, we delineate the energy metabolism that underpins pollen tube growth and illustrate how pollen plastids obtain ATP, NADPH, NADH, and acetyl-CoA for fatty acid biosynthesis. We also show that fermentation and pyruvate dehydrogenase bypass are not essential for pollen tube growth in Arabidopsis, in contrast to other plant species like tobacco and lily.
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Affiliation(s)
- Jinhong Liu
- grid.194645.b0000000121742757School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Shey-Li Lim
- grid.194645.b0000000121742757School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Jia Yi Zhong
- grid.194645.b0000000121742757School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Boon Leong Lim
- grid.194645.b0000000121742757School of Biological Sciences, University of Hong Kong, Hong Kong, China ,grid.194645.b0000000121742757HKU Shenzhen Institute of Research and Innovation, Shenzhen, China ,grid.10784.3a0000 0004 1937 0482State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
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Heyduk K, McAssey EV, Leebens‐Mack J. Differential timing of gene expression and recruitment in independent origins of CAM in the Agavoideae (Asparagaceae). THE NEW PHYTOLOGIST 2022; 235:2111-2126. [PMID: 35596719 PMCID: PMC9796715 DOI: 10.1111/nph.18267] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Crassulacean acid metabolism (CAM) photosynthesis has evolved repeatedly across the plant tree of life, however our understanding of the genetic convergence across independent origins remains hampered by the lack of comparative studies. Here, we explore gene expression profiles in eight species from the Agavoideae (Asparagaceae) encompassing three independent origins of CAM. Using comparative physiology and transcriptomics, we examined the variable modes of CAM in this subfamily and the changes in gene expression across time of day and between well watered and drought-stressed treatments. We further assessed gene expression and the molecular evolution of genes encoding phosphoenolpyruvate carboxylase (PPC), an enzyme required for primary carbon fixation in CAM. Most time-of-day expression profiles are largely conserved across all eight species and suggest that large perturbations to the central clock are not required for CAM evolution. By contrast, transcriptional response to drought is highly lineage specific. Yucca and Beschorneria have CAM-like expression of PPC2, a copy of PPC that has never been shown to be recruited for CAM in angiosperms. Together the physiological and transcriptomic comparison of closely related C3 and CAM species reveals similar gene expression profiles, with the notable exception of differential recruitment of carboxylase enzymes for CAM function.
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Affiliation(s)
- Karolina Heyduk
- School of Life SciencesUniversity of Hawaiʻi at MānoaHonoluluHI96822USA
- Department of Plant BiologyUniversity of GeorgiaAthensGA30602USA
- Department of Ecology and Evolutionary BiologyYale UniversityNew HavenCT06520USA
| | - Edward V. McAssey
- School of Life SciencesUniversity of Hawaiʻi at MānoaHonoluluHI96822USA
| | - Jim Leebens‐Mack
- Department of Plant BiologyUniversity of GeorgiaAthensGA30602USA
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6
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Kilburn R, Gerdis SA, She YM, Snedden WA, Plaxton WC. Autophosphorylation Inhibits RcCDPK1, a Dual-Specificity Kinase that Phosphorylates Bacterial-Type Phosphoenolpyruvate Carboxylase in Castor Oil Seeds. PLANT & CELL PHYSIOLOGY 2022; 63:683-698. [PMID: 35246690 DOI: 10.1093/pcp/pcac030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/01/2022] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) is a tightly regulated enzyme that plays a crucial anaplerotic role in central plant metabolism. Bacterial-type PEPC (BTPC) of developing castor oil seeds (COS) is highly expressed as a catalytic and regulatory subunit of a novel Class-2 PEPC heteromeric complex. Ricinus communis Ca2+-dependent protein kinase-1 (RcCDPK1) catalyzes in vivo inhibitory phosphorylation of COS BTPC at Ser451. Autokinase activity of recombinant RcCDPK1 was detected and 42 autophosphorylated Ser, Thr or Tyr residues were mapped via liquid chromatography-tandem mass spectrometry. Prior autophosphorylation markedly attenuated the ability of RcCDPK1 to transphosphorylate its BTPC substrate at Ser451. However, fully dephosphorylated RcCDPK1 rapidly autophosphorylated during the initial stages of a BTPC transphosphorylation assay. This suggests that Ca2+-dependent binding of dephospho-RcCDPK1 to BTPC may trigger a structural change that leads to rapid autophosphorylation and subsequent substrate transphosphorylation. Tyr30 was identified as an autophosphorylation site via LC-MS/MS and immunoblotting with a phosphosite-specific antibody. Tyr30 occurs at the junction of RcCDPK1's N-terminal variable (NTVD) and catalytic domains and is widely conserved in plant and protist CDPKs. Interestingly, a reduced rate and extent of BTPC transphosphorylation occurred with a RcCDPK1Y30F mutant. Prior research demonstrated that RcCDPK1's NTVD is essential for its Ca2+-dependent autophosphorylation or BTPC transphosphorylation activities but plays no role in target recognition. We propose that Tyr30 autophosphorylation facilitates a Ca2+-dependent interaction between the NTVD and Ca2+-activation domain that primes RcCDPK1 for transphosphorylating BTPC at Ser451. Our results provide insights into links between the post-translational control of COS anaplerosis, Ca2+-dependent signaling and the biological significance of RcCDPK1 autophosphorylation.
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Affiliation(s)
- Ryan Kilburn
- Department of Biology, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Suzanne A Gerdis
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON K1A OC6, Canada
| | - Yi-Min She
- Centre for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, Health Canada, Ottawa, ON K1A OK9, Canada
| | - Wayne A Snedden
- Department of Biology, Queen's University, Kingston, ON K7L 3N6, Canada
| | - William C Plaxton
- Department of Biology, Queen's University, Kingston, ON K7L 3N6, Canada
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7
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Shi F, Pang Z, Liu C, Zhou L, Tan C, Ren J, Ye X, Feng H, Liu Z. Whole-transcriptome analysis and construction of an anther development-related ceRNA network in Chinese cabbage (Brassica campestris L. ssp. pekinensis). Sci Rep 2022; 12:2667. [PMID: 35177672 PMCID: PMC8854722 DOI: 10.1038/s41598-022-06556-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 01/24/2022] [Indexed: 01/17/2023] Open
Abstract
Anther development is precisely regulated by a complex gene network, which is of great significance to plant breeding. However, the molecular mechanism of anther development in Chinese cabbage is unclear. Here, we identified microRNAs (miRNAs), mRNAs, long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) related to anther development in Chinese cabbage (Brassica campestris L. ssp. pekinensis) to construct competitive endogenous RNA (ceRNA) regulatory networks and provide valuable knowledge on anther development. Using whole-transcriptome sequencing, 9055, 585, 1344, and 165 differentially expressed mRNAs (DEmRNAs), miRNAs (DEmiRNAs), lncRNAs (DElncRNAs), and circRNAs (DEcircRNAs) were identified, respectively, in the anthers of Chinese cabbage compared with those in samples of the vegetative mass of four true leaves. An anther-related ceRNA regulatory network was constructed using miRNA targeting relationships, and 450 pairs of ceRNA relationships, including 97 DEmiRNA-DEmRNA, 281 DEmiRNA-DElncRNA, and 23 DEmiRNA-DEcircRNA interactions, were obtained. We identified important genes and their interactions with lncRNAs, circRNAs, and miRNAs involved in microsporogenesis, tapetum and callose layer development, pollen wall formation, and anther dehiscence. We analyzed the promoter activity of six predominant anther expression genes, which were expressed specifically in the anthers of Arabidopsis thaliana, indicating that they may play an important role in anther development of Chinese cabbage. This study lays the foundation for further research on the molecular mechanisms of anther growth and development in Chinese cabbage.
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Affiliation(s)
- Fengyan Shi
- Key Laboratory of Protected Horticulture (Shenyang Agricultural University), Ministry of Education, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Zhijin Pang
- Key Laboratory of Protected Horticulture (Shenyang Agricultural University), Ministry of Education, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Chuanhong Liu
- Key Laboratory of Protected Horticulture (Shenyang Agricultural University), Ministry of Education, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Li Zhou
- Integrated Technical Service Center, Bayuquan Customs, Yingkou, 115007, China
| | - Chong Tan
- Key Laboratory of Protected Horticulture (Shenyang Agricultural University), Ministry of Education, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Jie Ren
- Key Laboratory of Protected Horticulture (Shenyang Agricultural University), Ministry of Education, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Xueling Ye
- Key Laboratory of Protected Horticulture (Shenyang Agricultural University), Ministry of Education, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Hui Feng
- Key Laboratory of Protected Horticulture (Shenyang Agricultural University), Ministry of Education, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Zhiyong Liu
- Key Laboratory of Protected Horticulture (Shenyang Agricultural University), Ministry of Education, 120 Dongling Road, Shenhe District, Shenyang, 110866, China.
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Caburatan L, Park J. Differential Expression, Tissue-Specific Distribution, and Posttranslational Controls of Phosphoenolpyruvate Carboxylase. PLANTS (BASEL, SWITZERLAND) 2021; 10:1887. [PMID: 34579420 PMCID: PMC8468890 DOI: 10.3390/plants10091887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/02/2021] [Accepted: 09/08/2021] [Indexed: 11/17/2022]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) is a ubiquitous cytosolic enzyme, which is crucial for plant carbon metabolism. PEPC participates in photosynthesis by catalyzing the initial fixation of atmospheric CO2 and is abundant in both C4 and crassulacean acid metabolism leaves. PEPC is differentially expressed at different stages of plant development, mostly in leaves, but also in developing seeds. PEPC is known to show tissue-specific distribution in leaves and in other plant organs, such as roots, stems, and flowers. Plant PEPC undergoes reversible phosphorylation and monoubiquitination, which are posttranslational modifications playing important roles in regulatory processes and in protein localization. Phosphorylation activates the PEPC enzyme, making it more sensitive to glucose-6-phosphate and less sensitive to malate or aspartate. PEPC phosphorylation is known to be diurnally regulated and delicately changed in response to various environmental stimuli, in addition to light. PEPCs belong to a small gene family encoding several plant-type and distantly related bacterial-type PEPCs. This paper provides a minireview of the general information on PEPCs in both C4 and C3 plants.
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Affiliation(s)
- Lorrenne Caburatan
- Department of Fine Chemistry, Seoul National University of Science and Technology, Seoul 01811, Korea
| | - Joonho Park
- Department of Fine Chemistry, Seoul National University of Science and Technology, Seoul 01811, Korea
- Department of Nano Bio Engineering, Seoul National University of Science and Technology, Seoul 01811, Korea
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Cao J, Cheng G, Wang L, Maimaitijiang T, Lan H. Genome-Wide Identification and Analysis of the Phosphoenolpyruvate Carboxylase Gene Family in Suaeda aralocaspica, an Annual Halophyte With Single-Cellular C 4 Anatomy. FRONTIERS IN PLANT SCIENCE 2021; 12:665279. [PMID: 34527003 PMCID: PMC8435749 DOI: 10.3389/fpls.2021.665279] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 07/09/2021] [Indexed: 06/13/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) plays pivotal roles in the carbon fixation of photosynthesis and a variety of metabolic and stress pathways. Suaeda aralocaspica belongs to a single-cellular C4 species and carries out a photosynthetic pathway in an unusually elongated chlorenchyma cell, which is expected to have PEPCs with different characteristics. To identify the different isoforms of PEPC genes in S. aralocaspica and comparatively analyze their expression and regulation patterns as well as the biochemical and enzymatic properties in this study, we characterized a bacterial-type PEPC (BTPC; SaPEPC-4) in addition to the two plant-type PEPCs (PTPCs; SaPEPC-1 and SaPEPC-2) using a genome-wide identification. SaPEPC-4 presented a lower expression level in all test combinations with an unknown function; two SaPTPCs showed distinct subcellular localizations and different spatiotemporal expression patterns but positively responded to abiotic stresses. Compared to SaPEPC-2, the expression of SaPEPC-1 specifically in chlorenchyma cell tissues was much more active with the progression of development and under various stresses, particularly sensitive to light, implying the involvement of SaPEPC-1 in a C4 photosynthetic pathway. In contrast, SaPEPC-2 was more like a non-photosynthetic PEPC. The expression trends of two SaPTPCs in response to light, development, and abiotic stresses were also matched with the changes in PEPC activity in vivo (native) or in vitro (recombinant), and the biochemical properties of the two recombinant SaPTPCs were similar in response to various effectors while the catalytic efficiency, substrate affinity, and enzyme activity of SaPEPC-2 were higher than that of SaPEPC-1 in vitro. All the different properties between these two SaPTPCs might be involved in transcriptional (e.g., specific cis-elements), posttranscriptional [e.g., 5'-untranslated region (5'-UTR) secondary structure], or translational (e.g., PEPC phosphorylation/dephosphorylation) regulatory events. The comparative studies on the different isoforms of the PEPC gene family in S. aralocaspica may help to decipher their exact role in C4 photosynthesis, plant growth/development, and stress resistance.
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10
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Koendjbiharie JG, van Kranenburg R, Kengen SWM. The PEP-pyruvate-oxaloacetate node: variation at the heart of metabolism. FEMS Microbiol Rev 2021; 45:fuaa061. [PMID: 33289792 PMCID: PMC8100219 DOI: 10.1093/femsre/fuaa061] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022] Open
Abstract
At the junction between the glycolysis and the tricarboxylic acid cycle-as well as various other metabolic pathways-lies the phosphoenolpyruvate (PEP)-pyruvate-oxaloacetate node (PPO-node). These three metabolites form the core of a network involving at least eleven different types of enzymes, each with numerous subtypes. Obviously, no single organism maintains each of these eleven enzymes; instead, different organisms possess different subsets in their PPO-node, which results in a remarkable degree of variation, despite connecting such deeply conserved metabolic pathways as the glycolysis and the tricarboxylic acid cycle. The PPO-node enzymes play a crucial role in cellular energetics, with most of them involved in (de)phosphorylation of nucleotide phosphates, while those responsible for malate conversion are important redox enzymes. Variations in PPO-node therefore reflect the different energetic niches that organisms can occupy. In this review, we give an overview of the biochemistry of these eleven PPO-node enzymes. We attempt to highlight the variation that exists, both in PPO-node compositions, as well as in the roles that the enzymes can have within those different settings, through various recent discoveries in both bacteria and archaea that reveal deviations from canonical functions.
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Affiliation(s)
- Jeroen G Koendjbiharie
- Laboratory of Microbiology, Wageningen University, Stippeneng4, 6708 WE Wageningen, The Netherlands
| | - Richard van Kranenburg
- Laboratory of Microbiology, Wageningen University, Stippeneng4, 6708 WE Wageningen, The Netherlands
- Corbion, Arkelsedijk 46, 4206 AC Gorinchem, The Netherlands
| | - Servé W M Kengen
- Laboratory of Microbiology, Wageningen University, Stippeneng4, 6708 WE Wageningen, The Netherlands
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11
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Prokaryotic Expression of Phospho enolpyruvate Carboxylase Fragments from Peanut and Analysis of Osmotic Stress Tolerance of Recombinant Strains. PLANTS 2021; 10:plants10020365. [PMID: 33672856 PMCID: PMC7917721 DOI: 10.3390/plants10020365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/07/2021] [Accepted: 02/08/2021] [Indexed: 02/08/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) is a ubiquitous cytosolic enzyme that catalyzes the irreversible β-carboxylation of phosphoenolpyruvate (PEP) in presence of HCO3− to produce oxaloacetate (OAA) during carbon fixation and photosynthesis. It is well accepted that PEPC genes are expressed in plants upon stress. PEPC also supports the biosynthesis of biocompatible osmolytes in many plant species under osmotic stress. There are five isoforms of PEPC found in peanut (Arachis hypogaea L.), namely, AhPEPC1, AhPEPC2, AhPEPC3, AhPEPC4, and AhPEPC5. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that the gene expression patterns of these AhPEPC genes were different in mature seeds, stems, roots, flowers, and leaves. The expression of all the plant type PEPC (PTPCs) (AhPEPC1, AhPEPC2, AhPEPC3, and AhPEPC4) was relatively high in roots, while the bacterial type PEPC (BTPC) (AhPEPC5) showed a remarkable expression level in flowers. Principal component analysis (PCA) result showed that AhPEPC3 and AhPEPC4 are correlated with each other, indicating comparatively associations with roots, and AhPEPC5 have a very close relationship with flowers. In order to investigate the function of these AhPEPCs, the fragments of these five AhPEPC cDNA were cloned and expressed in Escherichia coli (E. coli). The recombinant proteins contained a conserved domain with a histidine site, which is important for enzyme catalysis. Results showed that protein fragments of AhPEPC1, AhPEPC2, and AhPEPC5 had remarkable expression levels in E. coli. These three recombinant strains were more sensitive at pH 9.0, and recombinant strains carrying AhPEPC2 and AhPEPC5 fragments exhibited more growth than the control strain with the presence of PEG6000. Our findings showed that the expression of the AhPEPC fragments may enhance the resistance of transformed E. coli to osmotic stress.
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12
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O'Leary B, Plaxton WC. Multifaceted functions of post-translational enzyme modifications in the control of plant glycolysis. CURRENT OPINION IN PLANT BIOLOGY 2020; 55:28-37. [PMID: 32200227 DOI: 10.1016/j.pbi.2020.01.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 01/24/2020] [Accepted: 01/31/2020] [Indexed: 06/10/2023]
Abstract
Glycolysis is a central feature of metabolism and its regulation plays important roles during plant developmental and stress responses. Recent advances in proteomics and mass spectrometry have documented extensive and dynamic post-translational modifications (PTMs) of most glycolytic enzymes in diverse plant tissues. Protein PTMs represent fundamental regulatory events that integrate signalling and gene expression with cellular metabolic networks, and can regulate glycolytic enzyme activity, localization, protein:protein interactions, moonlighting functions, and turnover. Serine/threonine phosphorylation and redox PTMs of cysteine thiol groups appear to be the most prevalent forms of reversible covalent modification involved in plant glycolytic control. Additional PTMs including monoubiquitination also have important functions. However, the molecular functions and mechanisms of most glycolytic enzyme PTMs remain unknown, and represent important objectives for future studies.
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Affiliation(s)
- Brendan O'Leary
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Australia
| | - William C Plaxton
- Department of Biology, Queen's University, Kingston, Ontario K7L3N6, Canada.
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13
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Ting MKY, She YM, Plaxton WC. Transcript profiling indicates a widespread role for bacterial-type phosphoenolpyruvate carboxylase in malate-accumulating sink tissues. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:5857-5869. [PMID: 29240945 PMCID: PMC5854131 DOI: 10.1093/jxb/erx399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) is an important regulatory enzyme situated at a key branch point of central plant metabolism. Plant genomes encode several plant-type PEPC (PTPC) isozymes, along with a distantly related bacterial-type PEPC (BTPC). BTPC is expressed at high levels in developing castor oil seeds where it tightly interacts with co-expressed PTPC polypeptides to form unusual hetero-octameric Class-2 PEPC complexes that are desensitized to allosteric inhibition by L-malate. Analysis of RNA-Seq and microarray transcriptome datasets revealed two distinct patterns of tissue-specific BTPC expression in vascular plants. Species such as Arabidopsis thaliana, strawberry, rice, maize, and poplar mainly exhibited pollen- or floral-specific BTPC expression. By contrast, BTPC transcripts were relatively abundant in developing castor, cotton, and soybean seeds, cassava tubers, as well as immature tomato, cucumber, grape, and avocado fruit. Immunoreactive 118 kDa BTPC polypeptides were detected on immunoblots of cucumber and tomato fruit extracts. Co-immunoprecipitation established that as in castor, BTPCs physically interact with endogenous PTPCs to form Class-2 PEPC complexes in tomato and cucumber fruit. We hypothesize that Class-2 PEPCs simultaneously maintain rapid anaplerotic PEP carboxylation and respiratory CO2 refixation in diverse, biosynthetically active sinks that accumulate high malate levels.
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Affiliation(s)
- Michael K Y Ting
- Department of Biology, Queen’s University, Kingston, Ontario, Canada
| | - Yi-Min She
- Centre for Biologics Evaluation Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada
| | - William C Plaxton
- Department of Biology, Queen’s University, Kingston, Ontario, Canada
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
- Correspondence:
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14
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Ying S, Hill AT, Pyc M, Anderson EM, Snedden WA, Mullen RT, She YM, Plaxton WC. Regulatory Phosphorylation of Bacterial-Type PEP Carboxylase by the Ca 2+-Dependent Protein Kinase RcCDPK1 in Developing Castor Oil Seeds. PLANT PHYSIOLOGY 2017; 174:1012-1027. [PMID: 28363991 PMCID: PMC5462042 DOI: 10.1104/pp.17.00288] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 03/30/2017] [Indexed: 05/04/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) is a tightly controlled cytosolic enzyme situated at a crucial branch point of central plant metabolism. In developing castor oil seeds (Ricinus communis) a novel, allosterically desensitized 910-kD Class-2 PEPC hetero-octameric complex, arises from a tight interaction between 107-kD plant-type PEPC and 118-kD bacterial-type (BTPC) subunits. The native Ca2+-dependent protein kinase (CDPK) responsible for in vivo inhibitory phosphorylation of Class-2 PEPC's BTPC subunit's at Ser-451 was highly purified from COS and identified as RcCDPK1 (XP_002526815) by mass spectrometry. Heterologously expressed RcCDPK1 catalyzed Ca2+-dependent, inhibitory phosphorylation of BTPC at Ser-451 while exhibiting: (i) a pair of Ca2+ binding sites with identical dissociation constants of 5.03 μM, (ii) a Ca2+-dependent electrophoretic mobility shift, and (iii) a marked Ca2+-independent hydrophobicity. Pull-down experiments established the Ca2+-dependent interaction of N-terminal GST-tagged RcCDPK1 with BTPC. RcCDPK1-Cherry localized to the cytosol and nucleus of tobacco bright yellow-2 cells, but colocalized with mitochondrial-surface associated BTPC-enhanced yellow fluorescent protein when both fusion proteins were coexpressed. Deletion analyses demonstrated that although its N-terminal variable domain plays an essential role in optimizing Ca2+-dependent RcCDPK1 autophosphorylation and BTPC transphosphorylation activity, it is not critical for in vitro or in vivo target recognition. Arabidopsis (Arabidopsis thaliana) CPK4 and soybean (Glycine max) CDPKβ are RcCDPK1 orthologs that effectively phosphorylated castor BTPC at Ser-451. Overall, the results highlight a potential link between cytosolic Ca2+ signaling and the posttranslational control of respiratory CO2 refixation and anaplerotic photosynthate partitioning in support of storage oil and protein biosynthesis in developing COS.
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Affiliation(s)
- Sheng Ying
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 (S.Y., A.T.H., W.A.S., W.C.P.)
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (M.P., A.M.A., R.T.M.)
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada K1A 0K9 (Y.-M.S.); and
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada K7L 3N6 (W.C.P.)
| | - Allyson T Hill
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 (S.Y., A.T.H., W.A.S., W.C.P.)
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (M.P., A.M.A., R.T.M.)
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada K1A 0K9 (Y.-M.S.); and
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada K7L 3N6 (W.C.P.)
| | - Michal Pyc
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 (S.Y., A.T.H., W.A.S., W.C.P.)
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (M.P., A.M.A., R.T.M.)
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada K1A 0K9 (Y.-M.S.); and
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada K7L 3N6 (W.C.P.)
| | - Erin M Anderson
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 (S.Y., A.T.H., W.A.S., W.C.P.)
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (M.P., A.M.A., R.T.M.)
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada K1A 0K9 (Y.-M.S.); and
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada K7L 3N6 (W.C.P.)
| | - Wayne A Snedden
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 (S.Y., A.T.H., W.A.S., W.C.P.)
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (M.P., A.M.A., R.T.M.)
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada K1A 0K9 (Y.-M.S.); and
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada K7L 3N6 (W.C.P.)
| | - Robert T Mullen
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 (S.Y., A.T.H., W.A.S., W.C.P.)
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (M.P., A.M.A., R.T.M.)
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada K1A 0K9 (Y.-M.S.); and
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada K7L 3N6 (W.C.P.)
| | - Yi-Min She
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 (S.Y., A.T.H., W.A.S., W.C.P.)
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (M.P., A.M.A., R.T.M.)
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada K1A 0K9 (Y.-M.S.); and
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada K7L 3N6 (W.C.P.)
| | - William C Plaxton
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 (S.Y., A.T.H., W.A.S., W.C.P.);
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (M.P., A.M.A., R.T.M.);
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada K1A 0K9 (Y.-M.S.); and
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada K7L 3N6 (W.C.P.)
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15
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O’Leary BM, Plaxton WC. Mechanisms and Functions of Post-translational Enzyme Modifications in the Organization and Control of Plant Respiratory Metabolism. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2017. [DOI: 10.1007/978-3-319-68703-2_13] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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16
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Ruiz-Ballesta I, Baena G, Gandullo J, Wang L, She YM, Plaxton WC, Echevarría C. New insights into the post-translational modification of multiple phosphoenolpyruvate carboxylase isoenzymes by phosphorylation and monoubiquitination during sorghum seed development and germination. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3523-36. [PMID: 27194739 PMCID: PMC4892742 DOI: 10.1093/jxb/erw186] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC; E.C. 4.1.1.31) was characterized in developing and germinating sorghum seeds, focusing on the transcript and polypeptide abundance of multiple plant-type phosphoenolpyruvate carboxylase (PTPC) genes, and the post-translational modification of each isoenzyme by phosphorylation versus monoubiquitination during germination. We observed high levels of SbPPC4 (Sb07g014960) transcripts during early development (stage I), and extensive transcript abundance of SbPPC2 (Sb02g021090) and SbPPC3 (Sb04g008720) throughout the entire life cycle of the seed. Although tandem mass spectrometry (MS) analysis of immunopurified PTPC indicated that four different PTPC isoenzymes were expressed in the developing and germinating seeds, SbPPC3 was the most abundant isozyme of the developing seed, and of the embryo and the aleurone layer of germinating seeds. In vivo phosphorylation of the different PTPC isoenzymes at their conserved N-terminal seryl phosphorylation site during germination was also established by MS/MS analysis. Furthermore, three of the four isoenzymes were partially monoubiquitinated, with MS/MS pinpointing SbPPC2 and SbPPC3 monoubiquitination at the conserved Lys-630 and Lys-624 residues, respectively. Our results demonstrate that monoubiquitination and phosphorylation simultaneously occur in vivo with different PTPC isozymes during seed germination. In addition, we show that PTPC monoubiquitination in germinating sorghum seeds always increases at stage II (emergence of the radicle), is maintained during the aerobic period of rapid cell division and reserve mobilization, and remains relatively constant until stage IV-V when coleoptiles initiate the formation of the photosynthetic tissues.
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Affiliation(s)
- Isabel Ruiz-Ballesta
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Avda Reina Mercedes nº 6, 41012 Sevilla, Spain
| | - Guillermo Baena
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Avda Reina Mercedes nº 6, 41012 Sevilla, Spain
| | - Jacinto Gandullo
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Avda Reina Mercedes nº 6, 41012 Sevilla, Spain
| | - Liqun Wang
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, 3888 Chenhua Road, Shanghai 201602, China State Key Laboratory of Crop Genetics and Germplasm Enhancement, Soybean Research Institute, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Yi-Min She
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, 3888 Chenhua Road, Shanghai 201602, China
| | | | - Cristina Echevarría
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Avda Reina Mercedes nº 6, 41012 Sevilla, Spain
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17
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Xie X, Kang H, Liu W, Wang GL. Comprehensive Profiling of the Rice Ubiquitome Reveals the Significance of Lysine Ubiquitination in Young Leaves. J Proteome Res 2015; 14:2017-25. [DOI: 10.1021/pr5009724] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xin Xie
- State
Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute
of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Department
of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Houxiang Kang
- State
Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute
of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wende Liu
- State
Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute
of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Guo-Liang Wang
- State
Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute
of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Department
of Plant Pathology, The Ohio State University, Columbus, Ohio 43210, United States
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18
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Shi J, Yi K, Liu Y, Xie L, Zhou Z, Chen Y, Hu Z, Zheng T, Liu R, Chen Y, Chen J. Phosphoenolpyruvate Carboxylase in Arabidopsis Leaves Plays a Crucial Role in Carbon and Nitrogen Metabolism. PLANT PHYSIOLOGY 2015; 167:671-81. [PMID: 25588735 PMCID: PMC4348777 DOI: 10.1104/pp.114.254474] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 01/12/2015] [Indexed: 05/20/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) is a crucial enzyme that catalyzes an irreversible primary metabolic reaction in plants.Previous studies have used transgenic plants expressing ectopic PEPC forms with diminished feedback inhibition to examine the role of PEPC in carbon and nitrogen metabolism. To date, the in vivo role of PEPC in carbon and nitrogen metabolism has not been analyzed in plants. In this study, we examined the role of PEPC in plants, demonstrating that PPC1 and PPC2 were highly expressed genes encoding PEPC in Arabidopsis (Arabidopsis thaliana) leaves and that PPC1 and PPC2 accounted for approximately 93% of total PEPC activity in the leaves. A double mutant, ppc1/ppc2, was constructed that exhibited a severe growth-arrest phenotype. The ppc1/ppc2 mutant accumulated more starch and sucrose than wild-type plants when seedlings were grown under normal conditions. Physiological and metabolic analysis revealed that decreased PEPC activity in the ppc1/ppc2 mutant greatly reduced the synthesis of malate and citrate and severely suppressed ammonium assimilation. Furthermore, nitrate levels in the ppc1/ppc2 mutant were significantly lower than those in wild-type plants due to the suppression of ammonium assimilation. Interestingly, starch and sucrose accumulation could be prevented and nitrate levels could be maintained by supplying the ppc1/ppc2 mutant with exogenous malate and glutamate, suggesting that low nitrogen status resulted in the alteration of carbon metabolism and prompted the accumulation of starch and sucrose in the ppc1/ppc2 mutant. Our results demonstrate that PEPC in leaves plays a crucial role in modulating the balance of carbon and nitrogen metabolism in Arabidopsis.
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19
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Sako K, Yanagawa Y, Kanai T, Sato T, Seki M, Fujiwara M, Fukao Y, Yamaguchi J. Proteomic Analysis of the 26S Proteasome Reveals Its Direct Interaction with Transit Peptides of Plastid Protein Precursors for Their Degradation. J Proteome Res 2014; 13:3223-30. [DOI: 10.1021/pr401245g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Kaori Sako
- Plant
Genomic Network Research Team, RIKEN Center for Sustainable Resource Science, 1-7-22
Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Yuki Yanagawa
- Plant-Microbe
Interaction Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan
| | - Tomoyuki Kanai
- Faculty
of Advanced Life Science and Graduate School of Life Science, Hokkaido University,
Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Takeo Sato
- Faculty
of Advanced Life Science and Graduate School of Life Science, Hokkaido University,
Kita-ku N10-W8, Sapporo 060-0810, Japan
| | - Motoaki Seki
- Plant
Genomic Network Research Team, RIKEN Center for Sustainable Resource Science, 1-7-22
Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Masayuki Fujiwara
- Plant
Global Educational Project, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | - Yoichiro Fukao
- Plant
Global Educational Project, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | - Junji Yamaguchi
- Faculty
of Advanced Life Science and Graduate School of Life Science, Hokkaido University,
Kita-ku N10-W8, Sapporo 060-0810, Japan
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20
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Phosphorylation of bacterial-type phosphoenolpyruvate carboxylase by a Ca2+-dependent protein kinase suggests a link between Ca2+ signalling and anaplerotic pathway control in developing castor oil seeds. Biochem J 2014; 458:109-18. [PMID: 24266766 DOI: 10.1042/bj20131191] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of the present study was to characterize the native protein kinase [BTPC (bacterial-type phosphoenolpyruvate carboxylase)-K (BTPC Ser451 kinase)] that in vivo phosphorylates Ser451 of the BTPC subunits of an unusual Class-2 PEP (phosphoenolpyruvate) carboxylase hetero-octameric complex of developing COS (castor oil seeds). COS BTPC-K was highly purified by PEG fractionation and hydrophobic size-exclusion anion-exchange and affinity chromatographies. BTPC-K phosphorylated BTPC strictly at Ser451 (Km=1.0 μM; pH optimum=7.3), a conserved target residue occurring within an intrinsically disordered region, as well as the protein histone III-S (Km=1.7 μM), but not a COS plant-type PEP carboxylase or sucrose synthase or α-casein. Its activity was Ca2+- (K0.5=2.7 μM) and ATP- (Km=6.6 μM) dependent, and markedly inhibited by trifluoperazine, 3-phosphoglycerate and PEP, but insensitive to calmodulin or 14-3-3 proteins. BTPC-K exhibited a native molecular mass of ~63 kDa and was soluble rather than membrane-bound. Inactivation and reactivation occurred upon BTPC-K's incubation with GSSG and then DTT respectively. Ser451 phosphorylation by BTPC-K inhibited BTPC activity by ~50% when assayed under suboptimal conditions (pH 7.3, 1 mM PEP and 10 mM L-malate). Our collective results indicate a possible link between cytosolic Ca2+ signalling and anaplerotic flux control in developing COS.
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21
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Shane MW, Fedosejevs ET, Plaxton WC. Reciprocal control of anaplerotic phosphoenolpyruvate carboxylase by in vivo monoubiquitination and phosphorylation in developing proteoid roots of phosphate-deficient harsh hakea. PLANT PHYSIOLOGY 2013; 161:1634-44. [PMID: 23407057 PMCID: PMC3613444 DOI: 10.1104/pp.112.213496] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 02/12/2013] [Indexed: 05/08/2023]
Abstract
Accumulating evidence indicates important functions for phosphoenolpyruvate (PEP) carboxylase (PEPC) in inorganic phosphate (Pi)-starved plants. This includes controlling the production of organic acid anions (malate, citrate) that are excreted in copious amounts by proteoid roots of nonmycorrhizal species such as harsh hakea (Hakea prostrata). This, in turn, enhances the bioavailability of mineral-bound Pi by solubilizing Al(3+), Fe(3+), and Ca(2+) phosphates in the rhizosphere. Harsh hakea thrives in the nutrient-impoverished, ancient soils of southwestern Australia. Proteoid roots from Pi-starved harsh hakea were analyzed over 20 d of development to correlate changes in malate and citrate exudation with PEPC activity, posttranslational modifications (inhibitory monoubiquitination versus activatory phosphorylation), and kinetic/allosteric properties. Immature proteoid roots contained an equivalent ratio of monoubiquitinated 110-kD and phosphorylated 107-kD PEPC polypeptides (p110 and p107, respectively). PEPC purification, immunoblotting, and mass spectrometry indicated that p110 and p107 are subunits of a 430-kD heterotetramer and that they both originate from the same plant-type PEPC gene. Incubation with a deubiquitinating enzyme converted the p110:p107 PEPC heterotetramer of immature proteoid roots into a p107 homotetramer while significantly increasing the enzyme's activity under suboptimal but physiologically relevant assay conditions. Proteoid root maturation was paralleled by PEPC activation (e.g. reduced Km [PEP] coupled with elevated I50 [malate and Asp] values) via in vivo deubiquitination of p110 to p107, and subsequent phosphorylation of the deubiquitinated subunits. This novel mechanism of posttranslational control is hypothesized to contribute to the massive synthesis and excretion of organic acid anions that dominates the carbon metabolism of the mature proteoid roots.
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Affiliation(s)
- Michael W Shane
- School of Plant Biology, Faculty of Science, University of Western Australia, Crawley, Western Australia 6009, Australia.
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22
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A comprehensive analysis of interaction and localization of Arabidopsis SKP1-like (ASK) and F-box (FBX) proteins. PLoS One 2012; 7:e50009. [PMID: 23166809 PMCID: PMC3499479 DOI: 10.1371/journal.pone.0050009] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 10/15/2012] [Indexed: 11/20/2022] Open
Abstract
F-Box (FBX) proteins are encoded by a multigene family present in major lineages of eukaryotes. A number of FBX proteins are shown to be subunits of SCF complex, a type of E3 ligases composed of SKP1, CULLIN, FBX and RBX1 proteins. The Arabidopsis SKP-LIKE (ASK) proteins are also members of a family and some of them interact with FBX proteins directly. To clarify how FBX and ASK proteins combine, we carried out a large-scale interaction analysis between FBX and ASK proteins using yeast two-hybrid assay (Y2H) in Arabidopsis thaliana. FBX proteins randomly chosen from those proteins that interacted with more than one ASK protein were further analyzed for their subcellular localization and in vivo interaction with ASK proteins. Furthermore, the expression profiles of FBX and ASK genes were compared. This work reveals that FBX proteins had a preference for interacting with ASK proteins depending on the domains they contain such as the FBX-associated (FBA) domain, the Kelch domain and leucine rich repeat (LRR). In addition, it was found that a single FBX protein could form multiple SCF complexes by interacting with several ASK proteins in many cases. Furthermore, it was suggested that the variation of SCF complexes were especially abundant in tissues related to male gametophyte and seed development. More than half of the FBX proteins studied did not interact with any of the ASK proteins, implying the necessity for certain regulations for their interaction in vivo and/or distinct roles from subunits of the SCF complex.
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Park J, Khuu N, Howard ASM, Mullen RT, Plaxton WC. Bacterial- and plant-type phosphoenolpyruvate carboxylase isozymes from developing castor oil seeds interact in vivo and associate with the surface of mitochondria. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 71:251-62. [PMID: 22404138 DOI: 10.1111/j.1365-313x.2012.04985.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) from developing castor oil seeds (COS) exists as two distinct oligomeric isoforms. The typical class-1 PEPC homotetramer consists of 107-kDa plant-type PEPC (PTPC) subunits, whereas the allosterically desensitized 910-kDa class-2 PEPC hetero-octamer arises from the association of class-1 PEPC with 118-kDa bacterial-type PEPC (BTPC) subunits. The in vivo interaction and subcellular location of COS BTPC and PTPC were assessed by imaging fluorescent protein (FP)-tagged PEPCs in tobacco suspension-cultured cells. The BTPC-FP mainly localized to cytoplasmic punctate/globular structures, identified as mitochondria by co-immunostaining of endogenous cytochrome oxidase. Inhibition of respiration with KCN resulted in proportional decreases and increases in mitochondrial versus cytosolic BTPC-FP, respectively. The FP-PTPC and NLS-FP-PTPC (containing an appended nuclear localization signal, NLS) localized to the cytosol and nucleus, respectively, but both co-localized with mitochondrial-associated BTPC when co-expressed with BTPC-FP. Transmission electron microscopy of immunogold-labeled developing COS revealed that BTPC and PTPC are localized at the mitochondrial (outer) envelope, as well as the cytosol. Moreover, thermolysin-sensitive BTPC and PTPC polypeptides were detected on immunoblots of purified COS mitochondria. Overall, our results demonstrate that: (i) COS BTPC and PTPC interact in vivo as a class-2 PEPC complex that associates with the surface of mitochondria, (ii) BTPC's unique and divergent intrinsically disordered region mediates its interaction with PTPC, whereas (iii) the PTPC-containing class-1 PEPC is entirely cytosolic. We hypothesize that mitochondrial-associated class-2 PEPC facilitates rapid refixation of respiratory CO(2) while sustaining a large anaplerotic flux to replenish tricarboxylic acid cycle C-skeletons withdrawn for biosynthesis.
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Affiliation(s)
- Joonho Park
- Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada
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Molecular and structural analysis of C4-specific PEPC isoform from Pennisetum glaucum plays a role in stress adaptation. Gene 2012; 500:224-31. [DOI: 10.1016/j.gene.2012.03.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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The bacterial-type phosphoenolpyruvate carboxylase isozyme from developing castor oil seeds is subject to in vivo regulatory phosphorylation at serine-451. FEBS Lett 2012; 586:1049-54. [PMID: 22569262 DOI: 10.1016/j.febslet.2012.02.054] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 02/08/2012] [Accepted: 02/26/2012] [Indexed: 11/22/2022]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) is a tightly controlled anaplerotic enzyme situated at a pivotal branch point of plant carbohydrate-metabolism. In developing castor oil seeds (COS) a novel allosterically-densensitized 910-kDa Class-2 PEPC hetero-octameric complex arises from a tight interaction between 107-kDa plant-type PEPC and 118-kDa bacterial-type PEPC (BTPC) subunits. Mass spectrometry and immunoblotting with anti-phosphoSer451 specific antibodies established that COS BTPC is in vivo phosphorylated at Ser451, a highly conserved target residue that occurs within an intrinsically disordered region. This phosphorylation was enhanced during COS development or in response to depodding. Kinetic characterization of a phosphomimetic (S451D) mutant indicated that Ser451 phosphorylation inhibits the catalytic activity of BTPC subunits within the Class-2 PEPC complex.
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Komatsu S, Hiraga S, Yanagawa Y. Proteomics techniques for the development of flood tolerant crops. J Proteome Res 2012; 11:68-78. [PMID: 22029422 DOI: 10.1021/pr2008863] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Proteomics is a useful analytical approach for investigating crop responses to stress. Recent remarkable advances in proteomic techniques allow for the identification of a wider range of proteins than was previously possible. The application of proteomic techniques to clarify the molecular mechanisms underlying crop responses to flooding stress may facilitate the development of flood tolerant crops. Flooding is an environmental stress found worldwide and may increase in frequency due to changes in global climate. Waterlogging resulting from flooding causes significant reductions in the growth and yield of several crops. Transient flooding displaces gases in soil pores and often causes hypoxia in plants grown on land with poor drainage. Changes in protein expression and post-translational modification of proteins occur as plants activate their defense system in response to flooding stress. In this review, we discuss the contributions that proteomic studies have made toward increasing our understanding of the well-organized cellular response to flooding in soybean and other crops. The biological relevance of the proteins identified using proteomic techniques in regard to crop stress tolerance will be discussed as well.
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Affiliation(s)
- Setsuko Komatsu
- National Institute of Crop Science, Tsukuba, Ibaraki, 305-8518, Japan.
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O’Leary B, Fedosejevs ET, Hill AT, Bettridge J, Park J, Rao SK, Leach CA, Plaxton WC. Tissue-specific expression and post-translational modifications of plant- and bacterial-type phosphoenolpyruvate carboxylase isozymes of the castor oil plant, Ricinus communis L. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:5485-95. [PMID: 21841182 PMCID: PMC3223045 DOI: 10.1093/jxb/err225] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
This study employs transcript profiling together with immunoblotting and co-immunopurification to assess the tissue-specific expression, protein:protein interactions, and post-translational modifications (PTMs) of plant- and bacterial-type phosphoenolpyruvate carboxylase (PEPC) isozymes (PTPC and BTPC, respectively) in the castor plant, Ricinus communis. Previous studies established that the Class-1 PEPC (PTPC homotetramer) of castor oil seeds (COS) is activated by phosphorylation at Ser-11 and inhibited by monoubiquitination at Lys-628 during endosperm development and germination, respectively. Elimination of photosynthate supply to developing COS by depodding caused the PTPC of the endosperm and cotyledon to be dephosphorylated, and then subsequently monoubiquitinated in vivo. PTPC monoubiquitination rather than phosphorylation is widespread throughout the castor plant and appears to be the predominant PTM of Class-1 PEPC that occurs in planta. The distinctive developmental patterns of PTPC phosphorylation versus monoubiquitination indicates that these two PTMs are mutually exclusive. By contrast, the BTPC: (i) is abundant in the inner integument, cotyledon, and endosperm of developing COS, but occurs at low levels in roots and cotyledons of germinated COS, (ii) shows a unique developmental pattern in leaves such that it is present in leaf buds and young expanding leaves, but undetectable in fully expanded leaves, and (iii) tightly interacts with co-expressed PTPC to form the novel and allosterically-desensitized Class-2 PEPC heteromeric complex. BTPC and thus Class-2 PEPC up-regulation appears to be a distinctive feature of rapidly growing and/or biosynthetically active tissues that require a large anaplerotic flux from phosphoenolpyruvate to replenish tricarboxylic acid cycle C-skeletons being withdrawn for anabolism.
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Affiliation(s)
- Brendan O’Leary
- Department of Biology, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Eric T. Fedosejevs
- Department of Biology, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Allyson T. Hill
- Department of Biology, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - James Bettridge
- Department of Biology, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Joonho Park
- Department of Biology, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Srinath K. Rao
- Department of Biology, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Craig A. Leach
- Progenra Inc., 271A Great Valley Parkway, Malvern, Pennsylvania 19355, USA
| | - William C. Plaxton
- Department of Biology, Queen’s University, Kingston, Ontario K7L 3N6, Canada
- Department of Biochemistry, Queen’s University, Kingston, Ontario K7L 3N6, Canada
- To whom correspondence should be addressed. E-mail:
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The remarkable diversity of plant PEPC (phosphoenolpyruvate carboxylase): recent insights into the physiological functions and post-translational controls of non-photosynthetic PEPCs. Biochem J 2011; 436:15-34. [DOI: 10.1042/bj20110078] [Citation(s) in RCA: 224] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PEPC [PEP (phosphoenolpyruvate) carboxylase] is a tightly controlled enzyme located at the core of plant C-metabolism that catalyses the irreversible β-carboxylation of PEP to form oxaloacetate and Pi. The critical role of PEPC in assimilating atmospheric CO2 during C4 and Crassulacean acid metabolism photosynthesis has been studied extensively. PEPC also fulfils a broad spectrum of non-photosynthetic functions, particularly the anaplerotic replenishment of tricarboxylic acid cycle intermediates consumed during biosynthesis and nitrogen assimilation. An impressive array of strategies has evolved to co-ordinate in vivo PEPC activity with cellular demands for C4–C6 carboxylic acids. To achieve its diverse roles and complex regulation, PEPC belongs to a small multigene family encoding several closely related PTPCs (plant-type PEPCs), along with a distantly related BTPC (bacterial-type PEPC). PTPC genes encode ~110-kDa polypeptides containing conserved serine-phosphorylation and lysine-mono-ubiquitination sites, and typically exist as homotetrameric Class-1 PEPCs. In contrast, BTPC genes encode larger ~117-kDa polypeptides owing to a unique intrinsically disordered domain that mediates BTPC's tight interaction with co-expressed PTPC subunits. This association results in the formation of unusual ~900-kDa Class-2 PEPC hetero-octameric complexes that are desensitized to allosteric effectors. BTPC is a catalytic and regulatory subunit of Class-2 PEPC that is subject to multi-site regulatory phosphorylation in vivo. The interaction between divergent PEPC polypeptides within Class-2 PEPCs adds another layer of complexity to the evolution, physiological functions and metabolic control of this essential CO2-fixing plant enzyme. The present review summarizes exciting developments concerning the functions, post-translational controls and subcellular location of plant PTPC and BTPC isoenzymes.
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O'Leary B, Rao S, Plaxton W. Phosphorylation of bacterial-type phosphoenolpyruvate carboxylase at Ser425 provides a further tier of enzyme control in developing castor oil seeds. Biochem J 2011; 433:65-74. [PMID: 20950272 PMCID: PMC3010082 DOI: 10.1042/bj20101361] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 10/12/2010] [Accepted: 10/15/2010] [Indexed: 11/17/2022]
Abstract
PEPC [PEP (phosphoenolpyruvate) carboxylase] is a tightly controlled anaplerotic enzyme situated at a pivotal branch point of plant carbohydrate metabolism. Two distinct oligomeric PEPC classes were discovered in developing COS (castor oil seeds). Class-1 PEPC is a typical homotetramer of 107 kDa PTPC (plant-type PEPC) subunits, whereas the novel 910-kDa Class-2 PEPC hetero-octamer arises from a tight interaction between Class-1 PEPC and 118 kDa BTPC (bacterial-type PEPC) subunits. Mass spectrometric analysis of immunopurified COS BTPC indicated that it is subject to in vivo proline-directed phosphorylation at Ser425. We show that immunoblots probed with phosphorylation site-specific antibodies demonstrated that Ser425 phosphorylation is promoted during COS development, becoming maximal at stage IX (maturation phase) or in response to depodding. Kinetic analyses of a recombinant, chimaeric Class-2 PEPC containing phosphomimetic BTPC mutant subunits (S425D) indicated that Ser425 phosphorylation results in significant BTPC inhibition by: (i) increasing its Km(PEP) 3-fold, (ii) reducing its I50 (L-malate and L-aspartate) values by 4.5- and 2.5-fold respectively, while (iii) decreasing its activity within the physiological pH range. The developmental pattern and kinetic influence of Ser425 BTPC phosphorylation is very distinct from the in vivo phosphorylation/activation of COS Class-1 PEPC's PTPC subunits at Ser11. Collectively, the results establish that BTPC's phospho-Ser425 content depends upon COS developmental and physiological status and that Ser425 phosphorylation attenuates the catalytic activity of BTPC subunits within a Class-2 PEPC complex. To the best of our knowledge, this study provides the first evidence for protein phosphorylation as a mechanism for the in vivo control of vascular plant BTPC activity.
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Key Words
- oil seed metabolism
- phosphoenolpyruvate carboxylase (pepc)
- phosphorylation site-specific antibodies
- protein phosphorylation
- ricinus communis (castor oil plant)
- site-directed mutagenesis
- atppc, plant-type phosphoenolpyruvate carboxylase isozyme from arabidopsis thaliana
- btpc, bacterial-type phosphoenolpyruvate carboxylase
- cos, castor (ricinus communis) oil seed(s)
- i50, inhibitor concentration producing 50% inhibition of enzyme activity
- pep, phosphoenolpyruvate
- pepc, pep carboxylase
- pp2a, protein phosphatase type-2a
- pp2ac, catalytic subunit of pp2a
- ptpc, plant-type pepc
- rcppc, btpc from ricinus communis
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Affiliation(s)
- Brendan O'Leary
- *Department of Biology, Queen's University, Kingston, ON, Canada K7L 3N6
| | - Srinath K. Rao
- *Department of Biology, Queen's University, Kingston, ON, Canada K7L 3N6
| | - William C. Plaxton
- *Department of Biology, Queen's University, Kingston, ON, Canada K7L 3N6
- †Department of Biochemistry, Queen's University, Kingston, ON, Canada K7L 3N6
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