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Eckardt NA, Avin-Wittenberg T, Bassham DC, Chen P, Chen Q, Fang J, Genschik P, Ghifari AS, Guercio AM, Gibbs DJ, Heese M, Jarvis RP, Michaeli S, Murcha MW, Mursalimov S, Noir S, Palayam M, Peixoto B, Rodriguez PL, Schaller A, Schnittger A, Serino G, Shabek N, Stintzi A, Theodoulou FL, Üstün S, van Wijk KJ, Wei N, Xie Q, Yu F, Zhang H. The lowdown on breakdown: Open questions in plant proteolysis. THE PLANT CELL 2024; 36:2931-2975. [PMID: 38980154 PMCID: PMC11371169 DOI: 10.1093/plcell/koae193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 05/16/2024] [Accepted: 06/19/2024] [Indexed: 07/10/2024]
Abstract
Proteolysis, including post-translational proteolytic processing as well as protein degradation and amino acid recycling, is an essential component of the growth and development of living organisms. In this article, experts in plant proteolysis pose and discuss compelling open questions in their areas of research. Topics covered include the role of proteolysis in the cell cycle, DNA damage response, mitochondrial function, the generation of N-terminal signals (degrons) that mark many proteins for degradation (N-terminal acetylation, the Arg/N-degron pathway, and the chloroplast N-degron pathway), developmental and metabolic signaling (photomorphogenesis, abscisic acid and strigolactone signaling, sugar metabolism, and postharvest regulation), plant responses to environmental signals (endoplasmic-reticulum-associated degradation, chloroplast-associated degradation, drought tolerance, and the growth-defense trade-off), and the functional diversification of peptidases. We hope these thought-provoking discussions help to stimulate further research.
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Affiliation(s)
| | - Tamar Avin-Wittenberg
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Diane C Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA
| | - Poyu Chen
- School of Biological Science and Technology, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Qian Chen
- Ministry of Agriculture and Rural Affairs Key Laboratory for Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Jun Fang
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford OX1 3RB, UK
| | - Pascal Genschik
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 12, rue du Général Zimmer, Strasbourg 67084, France
| | - Abi S Ghifari
- School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Angelica M Guercio
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA 95616, USA
| | - Daniel J Gibbs
- School of Biosciences, University of Birmingham, Edgbaston B1 2RU, UK
| | - Maren Heese
- Department of Developmental Biology, University of Hamburg, Ohnhorststr. 18, Hamburg 22609, Germany
| | - R Paul Jarvis
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford OX1 3RB, UK
| | - Simon Michaeli
- Department of Postharvest Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel
| | - Monika W Murcha
- School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Sergey Mursalimov
- Department of Postharvest Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel
| | - Sandra Noir
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 12, rue du Général Zimmer, Strasbourg 67084, France
| | - Malathy Palayam
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA 95616, USA
| | - Bruno Peixoto
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford OX1 3RB, UK
| | - Pedro L Rodriguez
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, Valencia ES-46022, Spain
| | - Andreas Schaller
- Department of Plant Physiology and Biochemistry, Institute of Biology, University of Hohenheim, Stuttgart 70599, Germany
| | - Arp Schnittger
- Department of Developmental Biology, University of Hamburg, Ohnhorststr. 18, Hamburg 22609, Germany
| | - Giovanna Serino
- Department of Biology and Biotechnology, Sapienza Universita’ di Roma, p.le A. Moro 5, Rome 00185, Italy
| | - Nitzan Shabek
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA 95616, USA
| | - Annick Stintzi
- Department of Plant Physiology and Biochemistry, Institute of Biology, University of Hohenheim, Stuttgart 70599, Germany
| | | | - Suayib Üstün
- Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Bochum 44780, Germany
| | - Klaas J van Wijk
- Section of Plant Biology, School of Integrative Plant Sciences (SIPS), Cornell University, Ithaca, NY 14853, USA
| | - Ning Wei
- School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Qi Xie
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Feifei Yu
- College of Grassland Science and Technology, China Agricultural University, Beijing 100083, China
| | - Hongtao Zhang
- Plant Sciences and the Bioeconomy, Rothamsted Research, Harpenden AL5 2JQ, UK
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2
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Sharma I, Talakayala A, Tiwari M, Asinti S, Kirti PB. A synchronized symphony: Intersecting roles of ubiquitin proteasome system and autophagy in cellular degradation. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 212:108700. [PMID: 38781635 DOI: 10.1016/j.plaphy.2024.108700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 05/01/2024] [Indexed: 05/25/2024]
Abstract
Eukaryotic cells have evolved dynamic quality control pathways and recycling mechanisms for cellular homeostasis. We discuss here, the two major systems for quality control, the ubiquitin-proteasome system (UPS) and autophagy that regulate cellular protein and organelle turnover and ensure efficient nutrient management, cellular integrity and long-term wellbeing of the plant. Both the pathways rely on ubiquitination signal to identify the targets for proteasomal and autophagic degradation, yet they use distinct degradation machinery to process these cargoes. Nonetheless, both UPS and autophagy operate together as an interrelated quality control mechanism where they communicate with each other at multiple nodes to coordinate and/or compensate the recycling mechanism particularly under development and environmental cues. Here, we provide an update on the cellular machinery of autophagy and UPS, unravel the nodes of their crosstalk and particularly highlight the factors responsible for their differential deployment towards protein, macromolecular complexes and organelles.
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Affiliation(s)
- Isha Sharma
- International Crop Research Institute for Semi-Arid Tropics, Patancheru, Hyderabad, India, 502324.
| | - Ashwini Talakayala
- International Crop Research Institute for Semi-Arid Tropics, Patancheru, Hyderabad, India, 502324
| | - Manish Tiwari
- CSIR-National Botanical Research Institute, 435, Rana Pratap Marg, Lucknow, 226001, Uttar Pradesh, India
| | - Sarath Asinti
- Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, Uttar Pradesh, 211007, India
| | - P B Kirti
- Agri Biotech Foundation, Rajendranagar, 500030, Hyderabad, India
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3
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Xu S, Wang Q, Liu Y, Liu Z, Zhao R, Sheng X. Latrunculin B facilitates gravitropic curvature of Arabidopsis root by inhibiting cell elongation, especially the cells in the lower flanks of the transition and elongation zones. PLANT SIGNALING & BEHAVIOR 2021; 16:1876348. [PMID: 33576719 PMCID: PMC7971231 DOI: 10.1080/15592324.2021.1876348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 01/10/2021] [Accepted: 01/11/2021] [Indexed: 05/29/2023]
Abstract
Gravitropism plays a critical role in the growth and development of plants. Previous reports proposed that the disruption of the actin cytoskeleton resulted in enhanced gravitropism; however, the mechanism underlying these phenomena is still unclear. In the present study, real-time observation on the effect of Latrunculin B (Lat B), a depolymerizing agent of microfilament cytoskeleton, on gravitropism of the primary root of Arabidopsis was undertaken using a vertical stage microscope. The results indicated that Lat B treatment prevented the growth of root, and the growth rates of upper and lower flanks of the horizontally placed root were asymmetrically inhibited. The growth of the lower flank was influenced by Lat B more seriously, resulting in an increased differential growth rate between the upper and lower flanks of the root. Further analysis indicated that Lat B affected cell growth mainly in the transition and elongation zones. Briefly, the current data revealed that Lat B treatment inhibited cell elongation, especially the cells in the lower flanks of the transition and elongation zones, which finally manifested as the facilitation of gravitropic curvature of the primary root.
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Affiliation(s)
- Shi Xu
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Qianqian Wang
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Yue Liu
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Zonghao Liu
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Ruoxin Zhao
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Xianyong Sheng
- College of Life Sciences, Capital Normal University, Beijing, China
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Pereksta D, King D, Saki F, Maroli A, Leonard E, Suseela V, May S, Castellanos Uribe M, Tharayil N, Van Hoewyk D. Proteasome Inhibition in Brassica napus Roots Increases Amino Acid Synthesis to Offset Reduced Proteolysis. PLANT & CELL PHYSIOLOGY 2020; 61:1028-1040. [PMID: 32311031 DOI: 10.1093/pcp/pcaa047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/10/2020] [Indexed: 06/11/2023]
Abstract
Cellular homeostasis is maintained by the proteasomal degradation of regulatory and misfolded proteins, which sustains the amino acid pool. Although proteasomes alleviate stress by removing damaged proteins, mounting evidence indicates that severe stress caused by salt, metal(oids), and some pathogens can impair the proteasome. However, the consequences of proteasome inhibition in plants are not well understood and even less is known about how its malfunctioning alters metabolic activities. Lethality causes by proteasome inhibition in non-photosynthetic organisms stem from amino acid depletion, and we hypothesized that plants respond to proteasome inhibition by increasing amino acid biosynthesis. To address these questions, the short-term effects of proteasome inhibition were monitored for 3, 8 and 48 h in the roots of Brassica napus treated with the proteasome inhibitor MG132. Proteasome inhibition did not affect the pool of free amino acids after 48 h, which was attributed to elevated de novo amino acid synthesis; these observations coincided with increased levels of sulfite reductase and nitrate reductase activities at earlier time points. However, elevated amino acid synthesis failed to fully restore protein synthesis. In addition, transcriptome analysis points to perturbed abscisic acid signaling and decreased sugar metabolism after 8 h of proteasome inhibition. Proteasome inhibition increased the levels of alternative oxidase but decreased aconitase activity, most sugars and tricarboxylic acid metabolites in root tissue after 48 h. These metabolic responses occurred before we observed an accumulation of reactive oxygen species. We discuss how the metabolic response to proteasome inhibition and abiotic stress partially overlap in plants.
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Affiliation(s)
- Dan Pereksta
- Biology Department, Coastal Carolina University, 107 Chanticleer Drive, Conway, SC 29526, USA
| | - Dillon King
- Biology Department, Coastal Carolina University, 107 Chanticleer Drive, Conway, SC 29526, USA
- Toxicology and Environmental Health. Duke University. 225 B Wing, Levine Science Research Center Durham, North Carolina 27708, USA
| | - Fahmida Saki
- Biology Department, Coastal Carolina University, 107 Chanticleer Drive, Conway, SC 29526, USA
- National Technical Institute for the Deaf 52 Lomb Memorial Dr, Rochester, NY 14623, USA
| | - Amith Maroli
- Department of Agriculture and Environmental Sciences, Clemson University, 105 Collins Street, Clemson, SC 29634, USA
| | - Elizabeth Leonard
- Department of Agriculture and Environmental Sciences, Clemson University, 105 Collins Street, Clemson, SC 29634, USA
| | - Vidya Suseela
- Department of Agriculture and Environmental Sciences, Clemson University, 105 Collins Street, Clemson, SC 29634, USA
| | - Sean May
- School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | | | - Nishanth Tharayil
- Department of Agriculture and Environmental Sciences, Clemson University, 105 Collins Street, Clemson, SC 29634, USA
| | - Doug Van Hoewyk
- Biology Department, Coastal Carolina University, 107 Chanticleer Drive, Conway, SC 29526, USA
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Han B, Xu H, Feng Y, Xu W, Cui Q, Liu A. Genomic Characterization and Expressional Profiles of Autophagy-Related Genes ( ATGs) in Oilseed Crop Castor Bean ( Ricinus communis L.). Int J Mol Sci 2020; 21:E562. [PMID: 31952322 PMCID: PMC7013546 DOI: 10.3390/ijms21020562] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/12/2020] [Accepted: 01/14/2020] [Indexed: 12/20/2022] Open
Abstract
Cellular autophagy is a widely-occurring conserved process for turning over damaged organelles or recycling cytoplasmic contents in cells. Although autophagy-related genes (ATGs) have been broadly identified from many plants, little is known about the potential function of autophagy in mediating plant growth and development, particularly in recycling cytoplasmic contents during seed development and germination. Castor bean (Ricinus communis) is one of the most important inedible oilseed crops. Its mature seed has a persistent and large endosperm with a hard and lignified seed coat, and is considered a model system for studying seed biology. Here, a total of 34 RcATG genes were identified in the castor bean genome and their sequence structures were characterized. The expressional profiles of these RcATGs were examined using RNA-seq and real-time PCR in a variety of tissues. In particular, we found that most RcATGs were significantly up-regulated in the later stage of seed coat development, tightly associated with the lignification of cell wall tissues. During seed germination, the expression patterns of most RcATGs were associated with the decomposition of storage oils. Furthermore, we observed by electron microscopy that the lipid droplets were directly swallowed by the vacuoles, suggesting that autophagy directly participates in mediating the decomposition of lipid droplets via the microlipophagy pathway in germinating castor bean seeds. This study provides novel insights into understanding the potential function of autophagy in mediating seed development and germination.
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Affiliation(s)
- Bing Han
- Department of Economic Plants and Biotechnology, and Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China; (B.H.); (W.X.)
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Hui Xu
- College of Life Sciences, Yunnan University, Kunming 650091, China; (H.X.); (Y.F.)
| | - Yingting Feng
- College of Life Sciences, Yunnan University, Kunming 650091, China; (H.X.); (Y.F.)
| | - Wei Xu
- Department of Economic Plants and Biotechnology, and Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China; (B.H.); (W.X.)
| | - Qinghua Cui
- College of Life Sciences, Yunnan University, Kunming 650091, China; (H.X.); (Y.F.)
| | - Aizhong Liu
- Key Laboratory for Forest Resources Conservation and Utilization in Southwest Mountains of China, College of Forestry, Southwest Forestry University, Kunming 650201, China
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Mendoza F, Berry C, Prestigiacomo L, Van Hoewyk D. Proteasome inhibition rapidly exacerbates photoinhibition and impedes recovery during high light stress in Chlamydomonas reinhardtii. BMC PLANT BIOLOGY 2020; 20:22. [PMID: 31931713 PMCID: PMC6958727 DOI: 10.1186/s12870-020-2236-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 12/31/2019] [Indexed: 05/23/2023]
Abstract
BACKGROUND Proteasomes remove regulatory proteins in eukaryotic cells, and control a variety of plant processes. Proteasomes are localized to the cytosol and nuclear, but their role in plant biology has recently been extended to chloroplasts, where it regulates TOC complex. This is turn controls the import of nuclear-encoded chloroplastic proteins, which remodels the chloroplast proteome and facilitates proper developmental transitions. Proteasomal regulation of the TOC complex also alleviates stressors that generate reactive oxygen species. These recent advances motivated us to determine if proteasome inhibition rapidly alters photosynthetic processes stemming from photoinhibition induced by high light. RESULTS The short-term effects of proteasome inhibition on photosystem II during light stress was measured in Chlamydomonas reinhardtii, which allowed the dual monitoring of both chlorophyll fluorescence and cell viability. After 48 h at low light, proteasome inhibition did not affect viability or photochemistiry, but decreased cell concentration and increased cell volume. Two hours of high light stress impaired the efficiency of photosystem II in proteasome-inhibited cells, as determined by a decrease in Fv/Fm and the electron transport rate. Elevated photoinhibition in proteasome inhibited cells was not caused by a decrease in cell viability or chlorophyll content. Recovery from photoinhibition was attenuated in MG132-treated cells, and suppressed growth of a reestablished culture. Proteasome inhibition decreased de novo protein synthesis, which possibly constrained the ability to remodel the plastid proteome, and thus hampering the ability to adjust to high light stress. CONCLUSION The proteasome is implicated in protecting photosystem II from photoinhibition. In addition to high light stress, other stressors- including metals, drought, and salt- are also known to generate reactive oxygen species localized to the chloroplast. Therefore, proteasome maintenance in plants may help protect photosynthesis during abiotic stress, which could increase crop yield during adverse conditions.
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Affiliation(s)
- Felipe Mendoza
- Coastal Carolina University, 113 Chanticleer Dr, Conway, SC, 29528, USA
| | - Carson Berry
- Coastal Carolina University, 113 Chanticleer Dr, Conway, SC, 29528, USA
| | | | - Doug Van Hoewyk
- Coastal Carolina University, 113 Chanticleer Dr, Conway, SC, 29528, USA.
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Downregulation of Thromboxane A 2 Receptor Occurs Mainly via Nuclear Factor-KappaB Signaling Pathway in Rat Renal Artery. Adv Pharmacol Sci 2017; 2017:6507048. [PMID: 28775740 PMCID: PMC5523459 DOI: 10.1155/2017/6507048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 04/05/2017] [Accepted: 06/11/2017] [Indexed: 11/17/2022] Open
Abstract
Thromboxane A2 (TXA2) acts on TXA2 receptors (TP) to regulate renal artery blood flow and subsequently contributes to the pathogenesis of renal ischemia. The present study was designed to examine if nuclear factor-kappaB (NF-κB) signaling pathway is involved in the downregulation of TP receptors in rat renal artery. Rat renal artery segments were organ cultured for 6 or 24 h. Downregulation of TP receptors was monitored using myograph (contractile function), real-time PCR (receptor mRNA), and immunohistochemistry (receptor protein). Specific inhibitors (MG-132 and BMS345541) for NF-κB signaling pathway were used to dissect the underlying molecular mechanisms involved. Compared to fresh (noncultured) segments, organ culture of the renal artery segments for 24 h induced a significant rightward shift of U46619 (TP receptor agonist) contractile response curves (pEC50: 6.89 ± 0.06 versus 6.48 ± 0.04, P < 0.001). This decreased contractile response to U46619 was paralleled with decreased TP receptor mRNA and protein expressions in the renal artery smooth muscle cells. Specific inhibitors (MG-132 and BMS345541) for NF-κB signaling pathway significantly abolished the decreased TP protein expression and receptor-mediated contractions. In conclusion, downregulation of TP receptors in the renal artery smooth muscle cells occurs mainly via the NF-κB signaling pathway.
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Yan Q, Wang J, Fu ZQ, Chen W. Endocytosis of AtRGS1 Is Regulated by the Autophagy Pathway after D-Glucose Stimulation. FRONTIERS IN PLANT SCIENCE 2017; 8:1229. [PMID: 28747924 PMCID: PMC5506085 DOI: 10.3389/fpls.2017.01229] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 06/29/2017] [Indexed: 05/21/2023]
Abstract
Sugar, as a signal molecule, has significant functions in signal transduction in which the seven-transmembrane regulator of G-protein signaling (RGS1) protein participates. D-Glucose causes endocytosis of the AtRGS1, leading to the physical uncoupling of AtRGS1 from AtGPA1 and thus a release of the GAP activity and concomitant sustained activation of G-protein signaling. Autophagy involves in massive degradation and recycling of cytoplasmic components to survive environmental stresses. The function of autophagy in AtRGS1 endocytosis during D-glucose stimulation has not been elucidated. In this study, we investigate the relationship between autophagy and AtRGS1 in response to D-glucose. Our findings demonstrated that AtRGS1 mediated the activation of autophagy by affecting the activities of the five functional groups of protein complexes and promoted the formation of autophagosomes under D-glucose application. When the autophagy pathway was interrupted, AtRGS1 recovery increased and endocytosis of ATRGS1 was inhibited, indicating that autophagy pathway plays an important role in regulating the endocytosis and recovery of AtRGS1 after D-glucose stimulation.
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Affiliation(s)
- Quanquan Yan
- Ministry of Education Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal UniversityGuangzhou, China
| | - Jingchun Wang
- Ministry of Education Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal UniversityGuangzhou, China
| | - Zheng Qing Fu
- Department of Biological Sciences, University of South Carolina, ColumbiaSC, United States
| | - Wenli Chen
- Ministry of Education Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal UniversityGuangzhou, China
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Sabetta W, Vannini C, Sgobba A, Marsoni M, Paradiso A, Ortolani F, Bracale M, Viggiano L, Blanco E, de Pinto MC. Cyclic AMP deficiency negatively affects cell growth and enhances stress-related responses in tobacco Bright Yellow-2 cells. PLANT MOLECULAR BIOLOGY 2016; 90:467-83. [PMID: 26786166 DOI: 10.1007/s11103-016-0431-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 01/05/2016] [Indexed: 05/24/2023]
Abstract
Cyclic adenosine 3',5'-monophosphate (cAMP) is a recognized second messenger; however, knowledge of cAMP involvement in plant physiological processes originates primarily from pharmacological studies. To obtain direct evidence for cAMP function in plants, tobacco Bright Yellow-2 (BY-2) cells were transformed with the cAMP sponge, which is a genetically encoded tool that reduces cAMP availability. BY-2 cells expressing the cAMP sponge (cAS cells), showed low levels of free cAMP and exhibited growth inhibition that was not proportional to the cAMP sponge transcript level. Growth inhibition in cAS cells was closely related to the precocious inhibition of mitosis due to a delay in cell cycle progression. The cAMP deficiency also enhanced antioxidant systems. Remarkable changes occurred in the cAS proteomic profile compared with that of wild-type (WT) cells. Proteins involved in translation, cytoskeletal organization, and cell proliferation were down-regulated, whereas stress-related proteins were up-regulated in cAS cells. These results support the hypothesis that BY-2 cells sense cAMP deficiency as a stress condition. Finally, many proteasome subunits were differentially expressed in cAS cells compared with WT cells, indicating that cAMP signaling broadly affects protein degradation via the ubiquitin/proteasome pathway.
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Affiliation(s)
- Wilma Sabetta
- Istituto di Bioscienze e Biorisorse, CNR, Via G. Amendola 165/A, 70126, Bari, Italy
| | - Candida Vannini
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Via H. J. Dunant 3, 21100, Varese, Italy
| | - Alessandra Sgobba
- Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro", via E. Orabona 4, 70125, Bari, Italy
| | - Milena Marsoni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Via H. J. Dunant 3, 21100, Varese, Italy
| | - Annalisa Paradiso
- Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro", via E. Orabona 4, 70125, Bari, Italy
| | - Francesca Ortolani
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Via H. J. Dunant 3, 21100, Varese, Italy
| | - Marcella Bracale
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Via H. J. Dunant 3, 21100, Varese, Italy
| | - Luigi Viggiano
- Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro", via E. Orabona 4, 70125, Bari, Italy
| | - Emanuela Blanco
- Istituto di Bioscienze e Biorisorse, CNR, Via G. Amendola 165/A, 70126, Bari, Italy
| | - Maria Concetta de Pinto
- Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro", via E. Orabona 4, 70125, Bari, Italy.
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10
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Wang X, Zhang S, Gao Y, Lü W, Sheng X. Different heavy metals have various effects on Picea wilsonii pollen germination and tube growth. PLANT SIGNALING & BEHAVIOR 2015; 10:e989015. [PMID: 25830714 PMCID: PMC4622978 DOI: 10.4161/15592324.2014.989015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 09/15/2014] [Accepted: 09/16/2014] [Indexed: 06/04/2023]
Abstract
Heavy metal pollution has became one of the realistic matters of globality. Previous reports indicated that heavy metals could significantly inhibit pollen germination and tube growth. In the present study, comparative studies on the effects of different heavy metals (As, Hg, Cd, Cr and Cu) on in-vitro picea wilsonii pollen germination and tube growth were carried out. Microscopic evaluation revealed that different heavy metals had various degree of toxicity on P. wilsonii pollen tube development. As showed the most toxic effects on pollen germination, which was followed by Hg and Cd, while Cr and Cu showed relatively lower toxicity. Besides, pollen tubes showed varying shapes in response to different heavy metal stress. Pollen tubes treated with Cd, Hg and As were usually characterized by irregularly increasing diameters and swelling tips with distinct cytoplasimic vacuolation. On the other hand, except for the slightly increased diameters, no obvious abnormal shape were observed in tubes treated with Cr or Cu. Lyso-Tracker Green staining indicated that only Cd-treated pollen tubes showed numerous vacuole-like acidic organelles, though cytoplasmic vacuolization were also observed in pollen tubes treated with Hg and A. In brief, our data indicated that different heavy metals have various effects on Picea wilsonii pollen germination and tube growth, and that in-vitro pollen culture might be used as a competent system for biomonitoring of air pollution.
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Affiliation(s)
- Xiaoxia Wang
- College of Life Sciences; Capital Normal University; Beijing, China
| | - Shasha Zhang
- College of Life Sciences; Capital Normal University; Beijing, China
| | - Yuan Gao
- College of Life Sciences; Capital Normal University; Beijing, China
| | - Wengeng Lü
- College of Life Sciences; Capital Normal University; Beijing, China
| | - Xianyong Sheng
- College of Life Sciences; Capital Normal University; Beijing, China
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11
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Cadmium stress disrupts the endomembrane organelles and endocytosis during Picea wilsonii pollen germination and tube growth. PLoS One 2014; 9:e94721. [PMID: 24722362 PMCID: PMC3983259 DOI: 10.1371/journal.pone.0094721] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 03/19/2014] [Indexed: 11/19/2022] Open
Abstract
As one of the most severe pollutants, cadmium has been reported to be harmful to plant cells, but the effects of cadmium on gymnosperm pollen germination and tube growth and the mechanism of this involvement are still unclear. Here, we report that cadmium not only strongly inhibited P. wilsonii pollen germination and tube growth, but also significantly altered tube morphology in a dose-dependent manner. Time-lapse images obtained with a laser scanning confocal microscope revealed that endocytosis was dramatically inhibited by cadmium stress. Further investigation with ER-Tracker dye indicated that cadmium stress reduced the number of the Golgi apparatus, and induced dilation of ER. Additionally, Lyso-Tracker staining showed that cadmium distinctly promoted the formation of acidic organelles in pollen tubes, likely derived from the dilated ER. Taken together, our studies indicated that P. wilsonii pollens were highly susceptible to cadmium stress, and that cadmium stress strongly inhibited pollen germination and tube growth by disrupting the endomembrane organelles, inhibiting endo/exocytosis, and forming acidic vacuoles, resulting in swollen tube tips and irregularly broadened tube diameters. These findings provide a new insight into the effects of cadmium toxicity on the tip growth of pollen tubes.
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Xie YH, Wang SW, Zhang Y, Edvinsson L, Xu CB. Nuclear Factor-kappaB-Mediated Endothelin Receptor Up-Regulation Increases Renal Artery Contractility in Rats. Basic Clin Pharmacol Toxicol 2013; 113:401-10. [PMID: 24034179 DOI: 10.1111/bcpt.12123] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 08/06/2013] [Indexed: 01/21/2023]
Abstract
Increased renal artery contractility leads to renal vasospasm and ischaemia as well as kidney damage. This study was designed to examine the hypothesis that organ culture of renal arteries induces transcriptional up-regulation of endothelin type A (ETA ) and type B2 (ETB2 ) receptors in the smooth muscle cells via activation of nuclear factor-kappaB (NF-κB) and subsequently increases renal artery contractility. Rat renal artery segments were organ-cultured for 6 or 24 hr to increase endothelin receptor-mediated contraction. To dissect molecular mechanisms involved in this process, inhibitors for NF-κB signalling pathway (MG-132 and BMS345541), transcription (actinomycin D) and translation (cycloheximide) were used during organ culture. Endothelin receptors were studied using a sensitive myograph (functional contractility), real-time PCR (mRNA analysis) and immunohistochemistry (protein localization). Compared with fresh segments, contractile responses to endothelin-1 (non-selective endothelin receptor agonist) and sarafotoxin 6c (selective ETB receptor agonist) were significantly increased in the segments after 24 hr of organ culture; ETB2 receptor-mediated maximal contraction increased from 2.7 ± 0.5 to 135.3 ± 5.1 (p < 0.001), and potency (pEC50 ) of ETA receptor agonist increased from 8.20 ± 0.04 to 8.72 ± 0.07 (p < 0.001). This was in parallel with increased corresponding mRNA and protein expression for ETA and ETB2 receptors. BMS345541, MG-132, actinomycin D or cyclohexamide, respectively, suppressed the up-regulation of ETA and ETB2 receptors. Immunostaining performed with specific antibody showed that IκB was phosphorylated during organ culture. In conclusion, activation of NF-κB mediates up-regulation of ETA and ETB2 receptors and subsequently increases renal artery contractility, which may contribute to renal vasospasm and ischaemia as well as kidney damage.
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Affiliation(s)
- Yan-Hua Xie
- Institute of Materia Medica, School of Pharmacy, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Si-Wang Wang
- Institute of Materia Medica, School of Pharmacy, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yaping Zhang
- Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, Shaanxi, China
| | - Lars Edvinsson
- Division of Experimental Vascular Research, Institute of Clinical Science in Lund, Lund University, Lund, Sweden
| | - Cang-Bao Xu
- Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, Shaanxi, China.,Division of Experimental Vascular Research, Institute of Clinical Science in Lund, Lund University, Lund, Sweden
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Dong J, Chen W. The role of autophagy in chloroplast degradation and chlorophagy in immune defenses during Pst DC3000 (AvrRps4) infection. PLoS One 2013; 8:e73091. [PMID: 24023671 PMCID: PMC3758262 DOI: 10.1371/journal.pone.0073091] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 07/19/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Chlorosis of leaf tissue normally observed during pathogen infection may result from the degradation of chloroplasts. There is a growing evidence to suggest that the chloroplast plays a significant role during pathogen infection. Although most degradation of the organelles and cellular structures in plants is mediated by autophagy, its role in chloroplast catabolism during pathogen infection is largely unknown. RESULTS In this study, we investigated the function of autophagy in chloroplast degradation during avirulent Pst DC3000 (AvrRps4) infection. We examined the expression of defensive marker genes and suppression of bacterial growth using the electrolyte leakage assay in normal light (N) and low light (L) growing environments of wild-type and atg5-1 plants during pathogen treatment. Stroma-targeted GFP proteins (CT-GFP) were observed with LysoTracker Red (LTR) staining of autophagosome-like structures in the vacuole. The results showed that Arabidopsis expressed a significant number of small GFP-labeled bodies when infected with avirulent Pst DC3000 (AvrRps4). While barely detectable, there were small GFP-labeled bodies in plants with the CT-GFP expressing atg5-1 mutation. The results showed that chloroplast degradation depends on autophagy and this may play an important role in inhibiting pathogen growth. CONCLUSION Autophagy plays a role in chloroplast degradation in Arabidopsis during avirulent Pst DC3000 (AvrRps4) infection. Autophagy dependent chloroplast degradation may be the primary source of reactive oxygen species (ROS) as well as the pathogen-response signaling molecules that induce the defense response.
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Affiliation(s)
- Junjian Dong
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China
- College of Life Science, Guangdong Key Laboratory of Biotechnology for Plant Development, South China Normal University, Guangzhou, Guangdong, China
| | - Wenli Chen
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China
- College of Life Science, Guangdong Key Laboratory of Biotechnology for Plant Development, South China Normal University, Guangzhou, Guangdong, China
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Saturated fatty acid palmitate-induced insulin resistance is accompanied with myotube loss and the impaired expression of health benefit myokine genes in C2C12 myotubes. Lipids Health Dis 2013; 12:104. [PMID: 23866690 PMCID: PMC3723881 DOI: 10.1186/1476-511x-12-104] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 07/02/2013] [Indexed: 02/05/2023] Open
Abstract
Background Excessive circular fatty acid, particlarly saturated fatty acid, can result in insulin resistance in skeletal muscle, but other adverse effects of fatty acid accumulation in myocytes remain unclear. Methods Differentiated C2C12 myotubes were used. The effects of palmitate on cell viability, glucose uptake, gene expression and myotube loss were evaluated by MTT assay, 2NBDG uptake, qRT-PCR, Western Blot and crystal staining-based myotube counting, respectively. In some expreiments, oleate was administrated, or the inhibitors of signaling pathways were applied. Results Palmitate-induced cellular insulin resistance was clarified by the reduced Akt phosphorylation, glucose uptake and Glut4 expression. Palmitate-caused myotube loss was clearly observed under microscope and proved by myotube counting and expression analysis of myotube marker genes. Moreover, palmitate-induced transcriptional suppression of three health benefit myokine genes (FNDC5, CTRP15 and FGF21) was found, and the different involvement of p38 and PI3K in the transcription of these genes was noticed. Conclusions Palmitate-induced insulin resistance accompanys myotube loss and the impaired expression of FNDC5, CTRP15 and FGF21genes in C2C12 myotubes. These results provide novel evidence indicating the negative role of high concentration of palmitate in myotubes.
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