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Du C, Liu M, Yan Y, Guo X, Cao X, Jiao Y, Zheng J, Ma Y, Xie Y, Li H, Yang C, Gao C, Zhao Q, Zhang Z. The U-box E3 ubiquitin ligase PUB35 negatively regulates ABA signaling through AFP1-mediated degradation of ABI5. THE PLANT CELL 2024; 36:3277-3297. [PMID: 38924024 PMCID: PMC11371175 DOI: 10.1093/plcell/koae194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 06/04/2024] [Accepted: 06/19/2024] [Indexed: 06/28/2024]
Abstract
Abscisic acid (ABA) signaling is crucial for plant responses to various abiotic stresses. The Arabidopsis (Arabidopsis thaliana) transcription factor ABA INSENSITIVE 5 (ABI5) is a central regulator of ABA signaling. ABI5 BINDING PROTEIN 1 (AFP1) interacts with ABI5 and facilitates its 26S-proteasome-mediated degradation, although the detailed mechanism has remained unclear. Here, we report that an ABA-responsive U-box E3 ubiquitin ligase, PLANT U-BOX 35 (PUB35), physically interacts with AFP1 and ABI5. PUB35 directly ubiquitinated ABI5 in a bacterially reconstituted ubiquitination system and promoted ABI5 protein degradation in vivo. ABI5 degradation was enhanced by AFP1 in response to ABA treatment. Phosphorylation of the T201 and T206 residues in ABI5 disrupted the ABI5-AFP1 interaction and affected the ABI5-PUB35 interaction and PUB35-mediated degradation of ABI5 in vivo. Genetic analysis of seed germination and seedling growth showed that pub35 mutants were hypersensitive to ABA as well as to salinity and osmotic stresses, whereas PUB35 overexpression lines were hyposensitive. Moreover, abi5 was epistatic to pub35, whereas the pub35-2 afp1-1 double mutant showed a similar ABA response to the two single mutants. Together, our results reveal a PUB35-AFP1 module involved in fine-tuning ABA signaling through ubiquitination and 26S-proteasome-mediated degradation of ABI5 during seed germination and seedling growth.
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Affiliation(s)
- Chang Du
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Meng Liu
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Yujie Yan
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Xiaoyu Guo
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Xiuping Cao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Yuzhe Jiao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Jiexuan Zheng
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Yanchun Ma
- College of Life Sciences, Liaocheng University, Liaocheng, 252000, Shandong, China
| | - Yuting Xie
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Hongbo Li
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Chengwei Yang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Caiji Gao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Qingzhen Zhao
- College of Life Sciences, Liaocheng University, Liaocheng, 252000, Shandong, China
| | - Zhonghui Zhang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China
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2
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Isono E, Li J, Pulido P, Siao W, Spoel SH, Wang Z, Zhuang X, Trujillo M. Protein degrons and degradation: Exploring substrate recognition and pathway selection in plants. THE PLANT CELL 2024; 36:3074-3098. [PMID: 38701343 PMCID: PMC11371205 DOI: 10.1093/plcell/koae141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/27/2024] [Accepted: 04/07/2024] [Indexed: 05/05/2024]
Abstract
Proteome composition is dynamic and influenced by many internal and external cues, including developmental signals, light availability, or environmental stresses. Protein degradation, in synergy with protein biosynthesis, allows cells to respond to various stimuli and adapt by reshaping the proteome. Protein degradation mediates the final and irreversible disassembly of proteins, which is important for protein quality control and to eliminate misfolded or damaged proteins, as well as entire organelles. Consequently, it contributes to cell resilience by buffering against protein or organellar damage caused by stresses. Moreover, protein degradation plays important roles in cell signaling, as well as transcriptional and translational events. The intricate task of recognizing specific proteins for degradation is achieved by specialized systems that are tailored to the substrate's physicochemical properties and subcellular localization. These systems recognize diverse substrate cues collectively referred to as "degrons," which can assume a range of configurations. They are molecular surfaces recognized by E3 ligases of the ubiquitin-proteasome system but can also be considered as general features recognized by other degradation systems, including autophagy or even organellar proteases. Here we provide an overview of the newest developments in the field, delving into the intricate processes of protein recognition and elucidating the pathways through which they are recruited for degradation.
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Affiliation(s)
- Erika Isono
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Jianming Li
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong
| | - Pablo Pulido
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049 Madrid, Spain
| | - Wei Siao
- Department of Biology, Aachen RWTH University, Institute of Molecular Plant Physiology, 52074 Aachen, Germany
| | - Steven H Spoel
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Zhishuo Wang
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Xiaohong Zhuang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Marco Trujillo
- Department of Biology, Aachen RWTH University, Institute of Molecular Plant Physiology, 52074 Aachen, Germany
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Man Y, Zhang Y, Chen L, Zhou J, Bu Y, Zhang X, Li X, Li Y, Jing Y, Lin J. The VAMP-associated protein VAP27-1 plays a crucial role in plant resistance to ER stress by modulating ER-PM contact architecture in Arabidopsis. PLANT COMMUNICATIONS 2024; 5:100929. [PMID: 38678366 PMCID: PMC11287176 DOI: 10.1016/j.xplc.2024.100929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 05/30/2023] [Accepted: 04/23/2024] [Indexed: 04/29/2024]
Abstract
The endoplasmic reticulum (ER) and the plasma membrane (PM) form ER-PM contact sites (EPCSs) that allow the ER and PM to exchange materials and information. Stress-induced disruption of protein folding triggers ER stress, and the cell initiates the unfolded protein response (UPR) to resist the stress. However, whether EPCSs play a role in ER stress in plants remains unclear. VESICLE-ASSOCIATED MEMBRANE PROTEIN (VAMP)-ASSOCIATED PROTEIN 27-1 (VAP27-1) functions in EPCS tethering and is encoded by a family of 10 genes (VAP27-1-10) in Arabidopsis thaliana. Here, we used CRISPR-Cas9-mediated genome editing to obtain a homozygous vap27-1 vap27-3 vap27-4 (vap27-1/3/4) triple mutant lacking three of the key VAP27 family members in Arabidopsis. The vap27-1/3/4 mutant exhibits defects in ER-PM connectivity and EPCS architecture, as well as excessive UPR signaling. We further showed that relocation of VAP27-1 to the PM mediates specific VAP27-1-related EPCS remodeling and expansion under ER stress. Moreover, the spatiotemporal dynamics of VAP27-1 at the PM increase ER-PM connectivity and enhance Arabidopsis resistance to ER stress. In addition, we revealed an important role for intracellular calcium homeostasis in the regulation of UPR signaling. Taken together, these results broaden our understanding of the molecular and cellular mechanisms of ER stress and UPR signaling in plants, providing additional clues for improving plant broad-spectrum resistance to different stresses.
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Affiliation(s)
- Yi Man
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, China
| | - Yue Zhang
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, China
| | - Linghui Chen
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, China
| | - Junhui Zhou
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, China
| | - Yufen Bu
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, China
| | - Xi Zhang
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, China
| | - Xiaojuan Li
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, China
| | - Yun Li
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, China
| | - Yanping Jing
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, China.
| | - Jinxing Lin
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, China.
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4
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Sun Y, Tian Z, Zuo D, Wang Q, Song G. GhUBC10-2 mediates GhGSTU17 degradation to regulate salt tolerance in cotton (Gossypium hirsutum). PLANT, CELL & ENVIRONMENT 2024; 47:1606-1624. [PMID: 38282268 DOI: 10.1111/pce.14839] [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: 06/27/2023] [Revised: 01/13/2024] [Accepted: 01/17/2024] [Indexed: 01/30/2024]
Abstract
Ubiquitin-conjugating enzyme (UBC) is a crucial component of the ubiquitin-proteasome system, which contributes to plant growth and development. While some UBCs have been identified as potential regulators of abiotic stress responses, the underlying mechanisms of this regulation remain poorly understood. Here, we report a cotton (Gossypium hirsutum) UBC gene, GhUBC10-2, which negatively regulates the salt stress response. We found that the gain of function of GhUBC10-2 in both Arabidopsis (Arabidopsis thaliana) and cotton leads to reduced salinity tolerance. Additionally, GhUBC10-2 interacts with glutathione S-transferase (GST) U17 (GhGSTU17), forming a heterodimeric complex that promotes GhGSTU17 degradation. Intriguingly, GhUBC10-2 can be self-polyubiquitinated, suggesting that it possesses E3-independent activity. Our findings provide new insights into the PTM of plant GST-mediated salt response pathways. Furthermore, we found that the WRKY transcription factor GhWRKY13 binds to the GhUBC10-2 promoter and suppresses its expression under salt conditions. Collectively, our study unveils a regulatory module encompassing GhWRKY13-GhUBC10-2-GhGSTU17, which orchestrates the modulation of reactive oxygen species homeostasis to enhance salt tolerance.
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Affiliation(s)
- Yaru Sun
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Zailong Tian
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
- National Nanfan Research Institute (Sanya), Chinese Academy of Agricultural Sciences, Sanya, Hainan, China
| | - Dongyun Zuo
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Qiaolian Wang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Guoli Song
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
- National Nanfan Research Institute (Sanya), Chinese Academy of Agricultural Sciences, Sanya, Hainan, China
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China
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5
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Thibault E, Brandizzi F. Post-translational modifications: emerging directors of cell-fate decisions during endoplasmic reticulum stress in Arabidopsis thaliana. Biochem Soc Trans 2024; 52:831-848. [PMID: 38600022 PMCID: PMC11088923 DOI: 10.1042/bst20231025] [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: 01/19/2024] [Revised: 03/23/2024] [Accepted: 04/02/2024] [Indexed: 04/12/2024]
Abstract
Homeostasis of the endoplasmic reticulum (ER) is critical for growth, development, and stress responses. Perturbations causing an imbalance in ER proteostasis lead to a potentially lethal condition known as ER stress. In ER stress situations, cell-fate decisions either activate pro-life pathways that reestablish homeostasis or initiate pro-death pathways to prevent further damage to the organism. Understanding the mechanisms underpinning cell-fate decisions in ER stress is critical for crop development and has the potential to enable translation of conserved components to ER stress-related diseases in metazoans. Post-translational modifications (PTMs) of proteins are emerging as key players in cell-fate decisions in situations of imbalanced ER proteostasis. In this review, we address PTMs orchestrating cell-fate decisions in ER stress in plants and provide evidence-based perspectives for where future studies may focus to identify additional PTMs involved in ER stress management.
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Affiliation(s)
- Ethan Thibault
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, U.S.A
- Department of Plant Biology, Michigan State University, East Lansing, MI, U.S.A
| | - Federica Brandizzi
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, U.S.A
- Department of Plant Biology, Michigan State University, East Lansing, MI, U.S.A
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, U.S.A
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6
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Yu F, Xie Q. ER-associated ubiquitin-conjugating enzyme: a key regulator of grain yield and stress resistance in crops. TRENDS IN PLANT SCIENCE 2024; 29:286-289. [PMID: 38160067 DOI: 10.1016/j.tplants.2023.11.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 11/10/2023] [Accepted: 11/30/2023] [Indexed: 01/03/2024]
Abstract
Recent research reveals the critical roles of endoplasmic reticulum (ER)-associated protein degradation (ERAD)-related ubiquitin-conjugating enzyme AtUBC32 orthologs and their partnering E3 ligases, which play dual roles in enhancing both crop yield and stress resistance. These findings open avenues for breeding high-yield, stress-tolerant crops and inspire further exploration of the ERAD pathway in agricultural innovation.
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Affiliation(s)
- Feifei Yu
- College of Grassland Science and Technology, China Agricultural University, Beijing 100083, China.
| | - Qi Xie
- Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; State Key Laboratory of Crop Germplasm Innovation and Molecular Breeding, National Center of Technology Innovation for Maize, Syngenta Group China, Beijing 102206, China; University of Chinese Academy of Sciences, Beijing 100049, China
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7
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Sun J, Zheng H. In Vivo Analysis of ER-Associated Protein Degradation and Ubiquitination in Arabidopsis thaliana. Methods Mol Biol 2024; 2772:301-309. [PMID: 38411824 DOI: 10.1007/978-1-0716-3710-4_23] [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] [Indexed: 02/28/2024]
Abstract
The endoplasmic reticulum (ER) is the cellular site for the biosynthesis of proteins and lipids. The ER is highly dynamic, whose homeostasis is maintained by proper ER shaping, unfolded protein response (UPR), ER-associated degradation (ERAD), and selective autophagy of the ER (ER-phagy). In ERAD and ER-phagy, unfolded/misfolded proteins are degraded in the 26S proteasome and the vacuole, respectively. Both processes are vital for normal plant development and plant responses to environmental stresses. While it is known that ubiquitination of a protein initiates EARD, recent research indicated that ubiquitination of a protein also promotes the turnover of the protein through ER-phagy. In this chapter, we describe in detail two in vivo methods for investigating (1) the degradation efficiency and (2) ubiquitination level of an ER-associated protein in Arabidopsis thaliana.
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Affiliation(s)
- Jiaqi Sun
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Huanquan Zheng
- Department of Biology, McGill University, Montreal, Quebec, Canada.
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8
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Duan Z, Chen K, Yang T, You R, Chen B, Li J, Liu L. Mechanisms of Endoplasmic Reticulum Protein Homeostasis in Plants. Int J Mol Sci 2023; 24:17599. [PMID: 38139432 PMCID: PMC10743519 DOI: 10.3390/ijms242417599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 12/24/2023] Open
Abstract
Maintenance of proteome integrity is essential for cell function and survival in changing cellular and environmental conditions. The endoplasmic reticulum (ER) is the major site for the synthesis of secretory and membrane proteins. However, the accumulation of unfolded or misfolded proteins can perturb ER protein homeostasis, leading to ER stress and compromising cellular function. Eukaryotic organisms have evolved sophisticated and conserved protein quality control systems to ensure protein folding fidelity via the unfolded protein response (UPR) and to eliminate potentially harmful proteins via ER-associated degradation (ERAD) and ER-phagy. In this review, we summarize recent advances in our understanding of the mechanisms of ER protein homeostasis in plants and discuss the crosstalk between different quality control systems. Finally, we will address unanswered questions in this field.
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Affiliation(s)
- Zhihao Duan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Kai Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Tao Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Ronghui You
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Binzhao Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Jianming Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong
| | - Linchuan Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
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9
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Langin G, González-Fuente M, Üstün S. The Plant Ubiquitin-Proteasome System as a Target for Microbial Manipulation. ANNUAL REVIEW OF PHYTOPATHOLOGY 2023; 61:351-375. [PMID: 37253695 DOI: 10.1146/annurev-phyto-021622-110443] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The plant immune system perceives pathogens to trigger defense responses. In turn, pathogens secrete effector molecules to subvert these defense responses. The initiation and maintenance of defense responses involve not only de novo synthesis of regulatory proteins and enzymes but also their regulated degradation. The latter is achieved through protein degradation pathways such as the ubiquitin-proteasome system (UPS). The UPS regulates all stages of immunity, from the perception of the pathogen to the execution of the response, and, therefore, constitutes an ideal candidate for microbial manipulation of the host. Pathogen effector molecules interfere with the plant UPS through several mechanisms. This includes hijacking general UPS functions or perturbing its ability to degrade specific targets. In this review, we describe how the UPS regulates different immunity-related processes and how pathogens subvert this to promote disease.
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Affiliation(s)
- Gautier Langin
- Centre for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany;
- Faculty of Biology and Biotechnology, Ruhr-University Bochum, Bochum, Germany
| | | | - Suayib Üstün
- Faculty of Biology and Biotechnology, Ruhr-University Bochum, Bochum, Germany
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Guan Y, Chang G, Zhao J, Wang Q, Qin J, Tang M, Wang S, Ma L, Ma J, Sun G, Zhou Y, Huang J. Parallel evolution of two AIM24 protein subfamilies and their conserved functions in ER stress tolerance in land plants. PLANT COMMUNICATIONS 2023; 4:100513. [PMID: 36578211 DOI: 10.1016/j.xplc.2022.100513] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/25/2022] [Accepted: 12/23/2022] [Indexed: 05/11/2023]
Abstract
Despite decades of efforts in genome sequencing and functional characterization, some important protein families remain poorly understood. In this study, we report the classification, evolution, and functions of the largely uncharacterized AIM24 protein family in plants, including the identification of a novel subfamily. We show that two AIM24 subfamilies (AIM24-A and AIM24-B) are commonly distributed in major plant groups. These two subfamilies not only have modest sequence similarities and different gene structures but also are of independent bacterial ancestry. We performed comparative functional investigations on the two AIM24 subfamilies using three model plants: the moss Physcomitrium patens, the liverwort Marchantia polymorpha, and the flowering plant Arabidopsis thaliana. Intriguingly, despite their significant differences in sequence and gene structure, both AIM24 subfamilies are involved in ER stress tolerance and the unfolded protein response (UPR). In addition, transformation of the AIM24-A gene from P. patens into the AIM24-B null mutant of A. thaliana could at least partially rescue ER stress tolerance and the UPR. We also discuss the role of AIM24 genes in plant development and other cellular activities. This study provides a unique example of parallel evolution in molecular functions and can serve as a foundation for further investigation of the AIM24 family in plants.
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Affiliation(s)
- Yanlong Guan
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Guanxiao Chang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Jinjie Zhao
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Qia Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Jiali Qin
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Mengmeng Tang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Shuanghua Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Lan Ma
- Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Jianchao Ma
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Guiling Sun
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Yun Zhou
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Jinling Huang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China; Department of Biology, East Carolina University, Greenville, NC 27858, USA.
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11
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Li J, Zhang B, Duan P, Yan L, Yu H, Zhang L, Li N, Zheng L, Chai T, Xu R, Li Y. An endoplasmic reticulum-associated degradation-related E2-E3 enzyme pair controls grain size and weight through the brassinosteroid signaling pathway in rice. THE PLANT CELL 2023; 35:1076-1091. [PMID: 36519262 PMCID: PMC10015164 DOI: 10.1093/plcell/koac364] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 11/08/2022] [Accepted: 12/12/2022] [Indexed: 05/16/2023]
Abstract
Grain size is an important agronomic trait, but our knowledge about grain size determination in crops is still limited. Endoplasmic reticulum (ER)-associated degradation (ERAD) is a special ubiquitin proteasome system that is involved in degrading misfolded or incompletely folded proteins in the ER. Here, we report that SMALL GRAIN 3 (SMG3) and DECREASED GRAIN SIZE 1 (DGS1), an ERAD-related E2-E3 enzyme pair, regulate grain size and weight through the brassinosteroid (BR) signaling pathway in rice (Oryza sativa). SMG3 encodes a homolog of Arabidopsis (Arabidopsis thaliana) UBIQUITIN CONJUGATING ENZYME 32, which is a conserved ERAD-associated E2 ubiquitin conjugating enzyme. SMG3 interacts with another grain size regulator, DGS1. Loss of function of SMG3 or DGS1 results in small grains, while overexpression of SMG3 or DGS1 leads to long grains. Further analyses showed that DGS1 is an active E3 ubiquitin ligase and colocates with SMG3 in the ER. SMG3 and DGS1 are involved in BR signaling. DGS1 ubiquitinates the BR receptor BRASSINOSTEROID INSENSITIVE 1 (BRI1) and affects its accumulation. Genetic analysis suggests that SMG3, DGS1, and BRI1 act together to regulate grain size and weight. In summary, our findings identify an ERAD-related E2-E3 pair that regulates grain size and weight, which gives insight into the function of ERAD in grain size control and BR signaling.
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Affiliation(s)
- Jing Li
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Plant Cell and Chromosome Engineering, CAS Centre for Excellence in Molecular Plant Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Baolan Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, CAS Centre for Excellence in Molecular Plant Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Penggen Duan
- State Key Laboratory of Plant Cell and Chromosome Engineering, CAS Centre for Excellence in Molecular Plant Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Li Yan
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Plant Cell and Chromosome Engineering, CAS Centre for Excellence in Molecular Plant Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Haiyue Yu
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Plant Cell and Chromosome Engineering, CAS Centre for Excellence in Molecular Plant Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Limin Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, CAS Centre for Excellence in Molecular Plant Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Na Li
- State Key Laboratory of Plant Cell and Chromosome Engineering, CAS Centre for Excellence in Molecular Plant Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Leiying Zheng
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Tuanyao Chai
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ran Xu
- Hainan Yazhou Bay Seed Laboratory, Sanya Nanfan Research Institute of Hainan University, Sanya 572025, China
- College of Tropical Crops Hainan University, Hainan University, Haikou 570288, China
| | - Yunhai Li
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Plant Cell and Chromosome Engineering, CAS Centre for Excellence in Molecular Plant Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- The Innovative of Seed Design, Chinese Academy of Sciences, Sanya 572025, China
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12
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Pan W, Li W, Liu L, Zhang H. Antiviral strategies: What can we learn from natural reservoirs? JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:1849-1855. [PMID: 36103243 DOI: 10.1111/jipb.13362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 09/11/2022] [Indexed: 06/15/2023]
Abstract
Viruses cause many severe diseases in both plants and animals, urging us to explore new antiviral strategies. In their natural reservoirs, viruses live and replicate while causing mild or no symptoms. Some animals, such as bats, are the predicted natural reservoir of multiple viruses, indicating that they possess broad-spectrum antiviral capabilities. Mechanisms of host defenses against viruses are generally studied independently in plants and animals. In this article, we speculate that some antiviral strategies of natural reservoirs are conserved between kingdoms. To verify this hypothesis, we created null mutants of 10-formyltetrahydrofolate synthetase (AtTHFS), an Arabidopsis thaliana homologue of methylenetetrahydrofolate dehydrogenase, cyclohydrolase and formyltetrahydrofolate synthetase 1 (MTHFD1), which encodes a positive regulator of viral replication in bats. We found that disruption of AtTHFS enhanced plant resistance to three different types of plant viruses, including the tomato spotted wilt virus (TSWV), the cucumber mosaic virus (CMV) and the beet severe curly top virus (BSCTV). These results demonstrate a novel antiviral strategy for plant breeding. We further discuss the approaches used to identify and study natural reservoirs of plant viruses, especially those hosting many viruses, and highlight the possibility of discovering new antiviral strategies from them for plant molecular breeding and antiviral therapy.
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Affiliation(s)
- Wenbo Pan
- Peking University Institute of Advanced Agricultural Sciences, Weifang, 261325, China
| | - Weiwei Li
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Lijing Liu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Huawei Zhang
- Peking University Institute of Advanced Agricultural Sciences, Weifang, 261325, China
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13
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Coordinative regulation of ERAD and selective autophagy in plants. Essays Biochem 2022; 66:179-188. [PMID: 35612379 DOI: 10.1042/ebc20210099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/02/2022] [Accepted: 05/06/2022] [Indexed: 12/30/2022]
Abstract
Endoplasmic reticulum-associated degradation (ERAD) plays important roles in plant development, hormone signaling, and plant-environment stress interactions by promoting the clearance of certain proteins or soluble misfolded proteins through the ubiquitin-proteasome system. Selective autophagy is involved in the autophagic degradation of protein aggregates mediated by specific selective autophagy receptors. These two major degradation routes co-operate with each other to relieve the cytotoxicity caused by ER stress. In this review, we analyze ERAD and different types of autophagy, including nonselective macroautophagy and ubiquitin-dependent and ubiquitin-independent selective autophagy in plants, and specifically summarize the selective autophagy receptors characterized in plants. In addition to being a part of selective autophagy, ERAD components also serve as their cargos. Moreover, an ubiquitinated substrate can be delivered to two distinguishable degradation systems, while the underlying determinants remain elusive. These excellent findings suggest an interdependent but complicated relationship between ERAD and selective autophagy. According to this point, we propose several key issues that need to be addressed in the future.
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14
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Post-translational modification: a strategic response to high temperature in plants. ABIOTECH 2022; 3:49-64. [PMID: 36304199 PMCID: PMC9590526 DOI: 10.1007/s42994-021-00067-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 12/22/2021] [Indexed: 11/21/2022]
Abstract
With the increasing global warming, high-temperature stress is affecting plant growth and development with greater frequency. Therefore, an increasing number of studies examining the mechanism of temperature response contribute to a more optimal understanding of plant growth under environmental pressure. Post-translational modification (PTM) provides the rapid reconnection of transcriptional programs including transcription factors and signaling proteins. It is vital that plants quickly respond to changes in the environment in order to survive under stressful situations. Herein, we discuss several types of PTMs that occur in response to warm-temperature and high-temperature stress, including ubiquitination, SUMOylation, phosphorylation, histone methylation, and acetylation. This review provides a valuable resolution to this issue to enable increased crop productivity at high temperatures.
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15
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Berger N, Demolombe V, Hem S, Rofidal V, Steinmann L, Krouk G, Crabos A, Nacry P, Verdoucq L, Santoni V. Root Membrane Ubiquitinome under Short-Term Osmotic Stress. Int J Mol Sci 2022; 23:ijms23041956. [PMID: 35216074 PMCID: PMC8879470 DOI: 10.3390/ijms23041956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/04/2022] [Accepted: 02/07/2022] [Indexed: 01/27/2023] Open
Abstract
Osmotic stress can be detrimental to plants, whose survival relies heavily on proteomic plasticity. Protein ubiquitination is a central post-translational modification in osmotic-mediated stress. In this study, we used the K-Ɛ-GG antibody enrichment method integrated with high-resolution mass spectrometry to compile a list of 719 ubiquitinated lysine (K-Ub) residues from 450 Arabidopsis root membrane proteins (58% of which are transmembrane proteins), thereby adding to the database of ubiquitinated substrates in plants. Although no ubiquitin (Ub) motifs could be identified, the presence of acidic residues close to K-Ub was revealed. Our ubiquitinome analysis pointed to a broad role of ubiquitination in the internalization and sorting of cargo proteins. Moreover, the simultaneous proteome and ubiquitinome quantification showed that ubiquitination is mostly not involved in membrane protein degradation in response to short osmotic treatment but that it is putatively involved in protein internalization, as described for the aquaporin PIP2;1. Our in silico analysis of ubiquitinated proteins shows that two E2 Ub-conjugating enzymes, UBC32 and UBC34, putatively target membrane proteins under osmotic stress. Finally, we revealed a positive role for UBC32 and UBC34 in primary root growth under osmotic stress.
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Affiliation(s)
- Nathalie Berger
- BPMP, CNRS, INRAE, Institut Agro, University Montpellier, 34060 Montpellier, France; (N.B.); (V.D.); (S.H.); (V.R.); (L.S.); (G.K.); (A.C.); (P.N.); (L.V.)
| | - Vincent Demolombe
- BPMP, CNRS, INRAE, Institut Agro, University Montpellier, 34060 Montpellier, France; (N.B.); (V.D.); (S.H.); (V.R.); (L.S.); (G.K.); (A.C.); (P.N.); (L.V.)
| | - Sonia Hem
- BPMP, CNRS, INRAE, Institut Agro, University Montpellier, 34060 Montpellier, France; (N.B.); (V.D.); (S.H.); (V.R.); (L.S.); (G.K.); (A.C.); (P.N.); (L.V.)
| | - Valérie Rofidal
- BPMP, CNRS, INRAE, Institut Agro, University Montpellier, 34060 Montpellier, France; (N.B.); (V.D.); (S.H.); (V.R.); (L.S.); (G.K.); (A.C.); (P.N.); (L.V.)
| | - Laura Steinmann
- BPMP, CNRS, INRAE, Institut Agro, University Montpellier, 34060 Montpellier, France; (N.B.); (V.D.); (S.H.); (V.R.); (L.S.); (G.K.); (A.C.); (P.N.); (L.V.)
- Center for Computational and Theoretical Biology, University of Würzburg, 97070 Würzburg, Germany
| | - Gabriel Krouk
- BPMP, CNRS, INRAE, Institut Agro, University Montpellier, 34060 Montpellier, France; (N.B.); (V.D.); (S.H.); (V.R.); (L.S.); (G.K.); (A.C.); (P.N.); (L.V.)
| | - Amandine Crabos
- BPMP, CNRS, INRAE, Institut Agro, University Montpellier, 34060 Montpellier, France; (N.B.); (V.D.); (S.H.); (V.R.); (L.S.); (G.K.); (A.C.); (P.N.); (L.V.)
| | - Philippe Nacry
- BPMP, CNRS, INRAE, Institut Agro, University Montpellier, 34060 Montpellier, France; (N.B.); (V.D.); (S.H.); (V.R.); (L.S.); (G.K.); (A.C.); (P.N.); (L.V.)
| | - Lionel Verdoucq
- BPMP, CNRS, INRAE, Institut Agro, University Montpellier, 34060 Montpellier, France; (N.B.); (V.D.); (S.H.); (V.R.); (L.S.); (G.K.); (A.C.); (P.N.); (L.V.)
| | - Véronique Santoni
- BPMP, CNRS, INRAE, Institut Agro, University Montpellier, 34060 Montpellier, France; (N.B.); (V.D.); (S.H.); (V.R.); (L.S.); (G.K.); (A.C.); (P.N.); (L.V.)
- Correspondence:
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16
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Huber M, Armbruster L, Etherington RD, De La Torre C, Hawkesford MJ, Sticht C, Gibbs DJ, Hell R, Wirtz M. Disruption of the N α-Acetyltransferase NatB Causes Sensitivity to Reductive Stress in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2022; 12:799954. [PMID: 35046984 PMCID: PMC8761761 DOI: 10.3389/fpls.2021.799954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 11/22/2021] [Indexed: 06/14/2023]
Abstract
In Arabidopsis thaliana, the evolutionary conserved N-terminal acetyltransferase (Nat) complexes NatA and NatB co-translationally acetylate 60% of the proteome. Both have recently been implicated in the regulation of plant stress responses. While NatA mediates drought tolerance, NatB is required for pathogen resistance and the adaptation to high salinity and high osmolarity. Salt and osmotic stress impair protein folding and result in the accumulation of misfolded proteins in the endoplasmic reticulum (ER). The ER-membrane resident E3 ubiquitin ligase DOA10 targets misfolded proteins for degradation during ER stress and is conserved among eukaryotes. In yeast, DOA10 recognizes conditional degradation signals (Ac/N-degrons) created by NatA and NatB. Assuming that this mechanism is preserved in plants, the lack of Ac/N-degrons required for efficient removal of misfolded proteins might explain the sensitivity of NatB mutants to protein harming conditions. In this study, we investigate the response of NatB mutants to dithiothreitol (DTT) and tunicamycin (TM)-induced ER stress. We report that NatB mutants are hypersensitive to DTT but not TM, suggesting that the DTT hypersensitivity is caused by an over-reduction of the cytosol rather than an accumulation of unfolded proteins in the ER. In line with this hypothesis, the cytosol of NatB depleted plants is constitutively over-reduced and a global transcriptome analysis reveals that their reductive stress response is permanently activated. Moreover, we demonstrate that doa10 mutants are susceptible to neither DTT nor TM, ruling out a substantial role of DOA10 in ER-associated protein degradation (ERAD) in plants. Contrary to previous findings in yeast, our data indicate that N-terminal acetylation (NTA) does not inhibit ER targeting of a substantial amount of proteins in plants. In summary, we provide further evidence that NatB-mediated imprinting of the proteome is vital for the response to protein harming stress and rule out DOA10 as the sole recognin for substrates in the plant ERAD pathway, leaving the role of DOA10 in plants ambiguous.
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Affiliation(s)
- Monika Huber
- Centre for Organismal Studies, Molecular Biology of Plants Group, Heidelberg University, Heidelberg, Germany
| | - Laura Armbruster
- Centre for Organismal Studies, Molecular Biology of Plants Group, Heidelberg University, Heidelberg, Germany
| | | | - Carolina De La Torre
- Institute of Clinical Chemistry, NGS Core Facility, Medical Faculty Mannheim of Heidelberg University, Heidelberg, Germany
| | | | - Carsten Sticht
- Institute of Clinical Chemistry, NGS Core Facility, Medical Faculty Mannheim of Heidelberg University, Heidelberg, Germany
| | - Daniel J. Gibbs
- School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Rüdiger Hell
- Centre for Organismal Studies, Molecular Biology of Plants Group, Heidelberg University, Heidelberg, Germany
| | - Markus Wirtz
- Centre for Organismal Studies, Molecular Biology of Plants Group, Heidelberg University, Heidelberg, Germany
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17
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Chen Q, Liu R, Wu Y, Wei S, Wang Q, Zheng Y, Xia R, Shang X, Yu F, Yang X, Liu L, Huang X, Wang Y, Xie Q. ERAD-related E2 and E3 enzymes modulate the drought response by regulating the stability of PIP2 aquaporins. THE PLANT CELL 2021; 33:2883-2898. [PMID: 34015125 PMCID: PMC8408458 DOI: 10.1093/plcell/koab141] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/12/2021] [Indexed: 05/20/2023]
Abstract
Endoplasmic reticulum-associated degradation (ERAD) is known to regulate plant responses to diverse stresses, yet its underlying molecular mechanisms and links to various stress signaling pathways are poorly understood. Here, we show that the ERAD component ubiquitin-conjugating enzyme UBC32 positively regulates drought tolerance in Arabidopsis thaliana by targeting the aquaporins PIP2;1 and PIP2;2 for degradation. Furthermore, we demonstrate that the RING-type ligase Rma1 acts together with UBC32 and that the E2 activity of UBC32 is essential for the ubiquitination of Rma1. This complex ubiquitinates a phosphorylated form of PIP2;1 at Lys276 to promote its degradation, thereby enhancing plant drought tolerance. Extending these molecular insights into crops, we show that overexpression of Arabidopsis UBC32 also improves drought tolerance in rice (Oryza sativa). Thus, beyond uncovering the molecular basis of an ERAD-regulated stress response, our study suggests multiple potential strategies for engineering crops with improved drought tolerance.
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Affiliation(s)
- Qian Chen
- State Key Laboratory of Agrobiotechnology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing 100193, China
- 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
| | - Ruijun Liu
- 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
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaorong Wu
- 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
| | - Shaowei Wei
- 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
| | - Qian Wang
- 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
| | - Yunna Zheng
- State Key Laboratory of Agrobiotechnology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Ran Xia
- 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
| | - Xiaoling Shang
- 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
| | - Feifei Yu
- 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
| | - Xiaoyuan Yang
- 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
| | - Lijing Liu
- School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China
| | - Xiahe Huang
- 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
| | - Yingchun Wang
- 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
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, 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
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Author for correspondence:
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18
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Liu R, Xia R, Xie Q, Wu Y. Endoplasmic reticulum-related E3 ubiquitin ligases: Key regulators of plant growth and stress responses. PLANT COMMUNICATIONS 2021; 2:100186. [PMID: 34027397 PMCID: PMC8132179 DOI: 10.1016/j.xplc.2021.100186] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/23/2021] [Accepted: 04/15/2021] [Indexed: 05/28/2023]
Abstract
Accumulating evidence has revealed that the ubiquitin proteasome system plays fundamental roles in the regulation of diverse cellular activities in eukaryotes. The ubiquitin protein ligases (E3s) are central to the proteasome system because of their ability to determine its substrate specificity. Several studies have demonstrated the essential role of a group of ER (endoplasmic reticulum)-localized E3s in the positive or negative regulation of cell homeostasis. Most ER-related E3s are conserved between plants and mammals, and a few plant-specific components have been reported. In this review, we summarize the functions of ER-related E3s in plant growth, ER-associated protein degradation and ER-phagy, abiotic and biotic stress responses, and hormone signaling. Furthermore, we highlight several questions that remain to be addressed and suggest directions for further research on ER-related E3 ubiquitin ligases.
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Affiliation(s)
- Ruijun Liu
- 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
| | - Ran Xia
- 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
| | - 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
| | - Yaorong Wu
- 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
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19
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Sun JL, Li JY, Wang MJ, Song ZT, Liu JX. Protein Quality Control in Plant Organelles: Current Progress and Future Perspectives. MOLECULAR PLANT 2021; 14:95-114. [PMID: 33137518 DOI: 10.1016/j.molp.2020.10.011] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 10/09/2020] [Accepted: 10/28/2020] [Indexed: 05/20/2023]
Abstract
The endoplasmic reticulum, chloroplasts, and mitochondria are major plant organelles for protein synthesis, photosynthesis, metabolism, and energy production. Protein homeostasis in these organelles, maintained by a balance between protein synthesis and degradation, is essential for cell functions during plant growth, development, and stress resistance. Nucleus-encoded chloroplast- and mitochondrion-targeted proteins and ER-resident proteins are imported from the cytosol and undergo modification and maturation within their respective organelles. Protein folding is an error-prone process that is influenced by both developmental signals and environmental cues; a number of mechanisms have evolved to ensure efficient import and proper folding and maturation of proteins in plant organelles. Misfolded or damaged proteins with nonnative conformations are subject to degradation via complementary or competing pathways: intraorganelle proteases, the organelle-associated ubiquitin-proteasome system, and the selective autophagy of partial or entire organelles. When proteins in nonnative conformations accumulate, the organelle-specific unfolded protein response operates to restore protein homeostasis by reducing protein folding demand, increasing protein folding capacity, and enhancing components involved in proteasome-associated protein degradation and autophagy. This review summarizes recent progress on the understanding of protein quality control in the ER, chloroplasts, and mitochondria in plants, with a focus on common mechanisms shared by these organelles during protein homeostasis.
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Affiliation(s)
- Jing-Liang Sun
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310027, China
| | - Jin-Yu Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310027, China
| | - Mei-Jing Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310027, China
| | - Ze-Ting Song
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310027, China
| | - Jian-Xiang Liu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310027, China.
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20
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The UBC27-AIRP3 ubiquitination complex modulates ABA signaling by promoting the degradation of ABI1 in Arabidopsis. Proc Natl Acad Sci U S A 2020; 117:27694-27702. [PMID: 33077597 DOI: 10.1073/pnas.2007366117] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Abscisic acid (ABA) is the key phytohormone in plant drought tolerance and stress adaptation. The clade A protein phosphatase 2Cs (PP2Cs) like ABI1 (ABA-INSENSITIVE 1) work as coreceptors of ABA and regulate multiple ABA responses. Ubiquitination of ABI1 has been proven to play important regulatory roles in ABA signaling. However, the specific ubiquitin conjugating enzyme (E2) involved is unknown. Here, we report that UBC27 is an active E2 that positively regulates ABA signaling and drought tolerance. UBC27 forms the E2-E3 pair with the drought regulator RING E3 ligase AIRP3. Both UBC27 and AIRP3 interact with ABI1 and affect the ubiquitination and degradation of ABI1. ABA activates the expression of UBC27, inhibits the proteasome degradation of UBC27, and enhances the interaction between UBC27 and ABI1 to increase its activity. These findings uncover a regulatory mechanism in ABA signaling and drought response and provide a further understanding of the plant ubiquitination system and ABA signaling pathway.
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21
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Schmidt CC, Vasic V, Stein A. Doa10 is a membrane protein retrotranslocase in ER-associated protein degradation. eLife 2020; 9:56945. [PMID: 32588820 PMCID: PMC7319771 DOI: 10.7554/elife.56945] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 05/28/2020] [Indexed: 12/17/2022] Open
Abstract
In endoplasmic reticulum-associated protein degradation (ERAD), membrane proteins are ubiquitinated, extracted from the membrane, and degraded by the proteasome. The cytosolic ATPase Cdc48 drives extraction by pulling on polyubiquitinated substrates. How hydrophobic transmembrane (TM) segments are moved from the phospholipid bilayer into cytosol, often together with hydrophilic and folded ER luminal protein parts, is not known. Using a reconstituted system with purified proteins from Saccharomyces cerevisiae, we show that the ubiquitin ligase Doa10 (Teb-4/MARCH6 in animals) is a retrotranslocase that facilitates membrane protein extraction. A substrate’s TM segment interacts with the membrane-embedded domain of Doa10 and then passively moves into the aqueous phase. Luminal substrate segments cross the membrane in an unfolded state. Their unfolding occurs on the luminal side of the membrane by cytoplasmic Cdc48 action. Our results reveal how a membrane-bound retrotranslocase cooperates with the Cdc48 ATPase in membrane protein extraction. The inside of a cell contains many different compartments called organelles, which are separated by membranes. Each organelle is composed of a unique set of proteins and performs specific roles in the cell. The endoplasmic reticulum, or ER for short, is an organelle where many proteins are produced. Most of these proteins are then released from the cell or sorted to other organelles. The ER has a strict quality control system that ensures any faulty proteins are quickly marked for the cell to destroy. However, the destruction process itself does not happen in the ER, so faulty proteins first need to leave this organelle. This is achieved by a group of proteins known as endoplasmic reticulum-associated protein degradation machinery (or ERAD for short). To extract a faulty protein from the ER, proteins of the ER and outside the ER cooperate. First, an ERAD protein called Doa10 attaches a small protein tag called ubiquitin to the faulty proteins to mark them for destruction. Then, outside of the ER, a protein called Cdc48 ‘grabs’ the ubiquitin tag and pulls. But that is only part of the story. Many of the proteins made by the ER have tethers that anchor them firmly to the membrane, making them much harder to remove. To get a better idea of how the extraction works, Schmidt et al. rebuilt the ERAD machinery in a test tube. This involved purifying proteins from yeast and inserting them into artificial membranes, allowing closer study of each part of the process. This revealed that attaching ubiquitin tags to faulty proteins is only one part of Doa10's role; it also participates in the extraction itself. Part of Doa10 resides within the membrane, and this ‘membrane-spanning domain’ can interact with faulty proteins, loosening their membrane anchors. At the same time, Cdc48 pulls from the outside. This pulling force causes the faulty proteins to unfold, allowing them to pass through the membrane. Given these findings, the next step is to find out exactly how Doa10 works by looking at its three-dimensional structure. This could have implications not only for the study of ERAD, but of similar quality control processes in other organelles too. A build-up of faulty proteins can cause diseases like neurodegeneration, so understanding how cells remove faulty proteins could help future medical research.
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Affiliation(s)
- Claudia C Schmidt
- Research Group Membrane Protein Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Vedran Vasic
- Research Group Membrane Protein Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Alexander Stein
- Research Group Membrane Protein Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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22
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Feng H, Wang S, Dong D, Zhou R, Wang H. Arabidopsis Ubiquitin-Conjugating Enzymes UBC7, UBC13, and UBC14 Are Required in Plant Responses to Multiple Stress Conditions. PLANTS 2020; 9:plants9060723. [PMID: 32521733 PMCID: PMC7355981 DOI: 10.3390/plants9060723] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 01/24/2023]
Abstract
Protein ubiquitination plays important roles in plants, including stress responses. The ubiquitin (Ub) E2 enzymes are required in the transfer of Ub to a substrate and are also important in determining the Ub-chain linkage specificity. However, for many of the 37 E2 genes in Arabidopsis thaliana, there is currently little or no understanding of their functions. In this study, we investigated three members of an E2 subfamily. The single, double, and triple mutants of UBC7, UBC13, and UBC14 did not show any phenotypic changes under normal conditions, but were more sensitive than the wild-type (WT) plants to multiple stress conditions, suggesting that the three genes are not critical for normal growth, but required in plant stress responses. The severity of the phenotypes increased from single to triple mutants, suggesting that the functions of the three genes are not completely redundant. The three E2s are closely related to the yeast Ubc7 and its homologs in animals and human, which are an important component of the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway. The stress sensitivity phenotypes of the mutants and shared evolutionary root with the Ubc7 homologs in yeast and metazoans suggest that UBC7, UBC13, and UBC14 may function in the plant ERAD pathway.
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Affiliation(s)
- Hui Feng
- College of Agriculture, Guangxi University, Nanning 530005, China; (H.F.); (D.D.)
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada;
| | - Sheng Wang
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada;
| | - Dengfeng Dong
- College of Agriculture, Guangxi University, Nanning 530005, China; (H.F.); (D.D.)
| | - Ruiyang Zhou
- College of Agriculture, Guangxi University, Nanning 530005, China; (H.F.); (D.D.)
- Correspondence: (R.Z.); (H.W.)
| | - Hong Wang
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada;
- Correspondence: (R.Z.); (H.W.)
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23
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Liu W, Tang X, Qi X, Fu X, Ghimire S, Ma R, Li S, Zhang N, Si H. The Ubiquitin Conjugating Enzyme: An Important Ubiquitin Transfer Platform in Ubiquitin-Proteasome System. Int J Mol Sci 2020; 21:E2894. [PMID: 32326224 PMCID: PMC7215765 DOI: 10.3390/ijms21082894] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 11/24/2022] Open
Abstract
Owing to a sessile lifestyle in nature, plants are routinely faced with diverse hostile environments such as various abiotic and biotic stresses, which lead to accumulation of free radicals in cells, cell damage, protein denaturation, etc., causing adverse effects to cells. During the evolution process, plants formed defense systems composed of numerous complex gene regulatory networks and signal transduction pathways to regulate and maintain the cell homeostasis. Among them, ubiquitin-proteasome pathway (UPP) is the most versatile cellular signal system as well as a powerful mechanism for regulating many aspects of the cell physiology because it removes most of the abnormal and short-lived peptides and proteins. In this system, the ubiquitin-conjugating enzyme (E2) plays a critical role in transporting ubiquitin from the ubiquitin-activating enzyme (E1) to the ubiquitin-ligase enzyme (E3) and substrate. Nevertheless, the comprehensive study regarding the role of E2 enzymes in plants remains unexplored. In this review, the ubiquitination process and the regulatory role that E2 enzymes play in plants are primarily discussed, with the focus particularly put on E2's regulation of biological functions of the cell.
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Affiliation(s)
- Weigang Liu
- College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China; (W.L.); (S.G.); (R.M.); (S.L.)
- Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; (X.T.); (X.Q.); (X.F.)
| | - Xun Tang
- Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; (X.T.); (X.Q.); (X.F.)
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China;
| | - Xuehong Qi
- Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; (X.T.); (X.Q.); (X.F.)
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China;
| | - Xue Fu
- Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; (X.T.); (X.Q.); (X.F.)
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China;
| | - Shantwana Ghimire
- College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China; (W.L.); (S.G.); (R.M.); (S.L.)
- Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; (X.T.); (X.Q.); (X.F.)
| | - Rui Ma
- College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China; (W.L.); (S.G.); (R.M.); (S.L.)
| | - Shigui Li
- College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China; (W.L.); (S.G.); (R.M.); (S.L.)
| | - Ning Zhang
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China;
| | - Huaijun Si
- College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China; (W.L.); (S.G.); (R.M.); (S.L.)
- Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; (X.T.); (X.Q.); (X.F.)
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China;
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24
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Chen Q, Yu F, Xie Q. Insights into endoplasmic reticulum-associated degradation in plants. THE NEW PHYTOLOGIST 2020; 226:345-350. [PMID: 31838748 DOI: 10.1111/nph.16369] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 11/22/2019] [Indexed: 06/10/2023]
Abstract
Secretory and transmembrane protein synthesis and initial modification are essential processes in protein maturation, and these processes are important for maintaining protein homeostasis in the endoplasmic reticulum (ER). ER homeostasis can be disrupted by the accumulation of misfolded proteins, resulting in ER stress, due to specific intra- or extracellular stresses. Processes including the unfolded protein response (UPR), ER-associated degradation (ERAD) and autophagy are thought to play important roles in restoring ER homeostasis. Here, we focus on summarizing and analysing recent advances in our understanding of the role of ERAD in plant physiological processes, especially in plant adaption to biotic and abiotic stresses, and also identify several issues that still need to be resolved in this field.
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Affiliation(s)
- Qian Chen
- 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
- State Key Laboratory of Agrobiotechnology and Ministry of Agriculture Key Laboratory of Plant Pathology, China Agricultural University, Beijing, 100193, China
| | - Feifei Yu
- 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
| | - 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
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25
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PAWH1 and PAWH2 are plant-specific components of an Arabidopsis endoplasmic reticulum-associated degradation complex. Nat Commun 2019; 10:3492. [PMID: 31375683 PMCID: PMC6677890 DOI: 10.1038/s41467-019-11480-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Accepted: 07/16/2019] [Indexed: 01/23/2023] Open
Abstract
Endoplasmic reticulum-associated degradation (ERAD) is a unique mechanism to degrade misfolded proteins via complexes containing several highly-conserved ER-anchored ubiquitin ligases such as HMG-CoA reductase degradation1 (Hrd1). Arabidopsis has a similar Hrd1-containing ERAD machinery; however, our knowledge of this complex is limited. Here we report two closely-related Arabidopsis proteins, Protein Associated With Hrd1-1 (PAWH1) and PAWH2, which share a conserved domain with yeast Altered Inheritance of Mitochondria24. PAWH1 and PAWH2 localize to the ER membrane and associate with Hrd1 via EMS-mutagenized Bri1 Suppressor7 (EBS7), a plant-specific component of the Hrd1 complex. Simultaneously elimination of two PAWHs constitutively activates the unfolded protein response and compromises stress tolerance. Importantly, the pawh1 pawh2 double mutation reduces the protein abundance of EBS7 and Hrd1 and inhibits degradation of several ERAD substrates. Our study not only discovers additional plant-specific components of the Arabidopsis Hrd1 complex but also reveals a distinct mechanism for regulating the Hrd1 stability.
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26
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Zhang R, Chen H, Duan M, Zhu F, Wen J, Dong J, Wang T. Medicago falcata MfSTMIR, an E3 ligase of endoplasmic reticulum-associated degradation, is involved in salt stress response. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:680-696. [PMID: 30712282 PMCID: PMC6849540 DOI: 10.1111/tpj.14265] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 05/28/2023]
Abstract
Recent studies on E3 of endoplasmic reticulum (ER)-associated degradation (ERAD) in plants have revealed homologs in yeast and animals. However, it remains unknown whether the plant ERAD system contains a plant-specific E3 ligase. Here, we report that MfSTMIR, which encodes an ER-membrane-localized RING E3 ligase that is highly conserved in leguminous plants, plays essential roles in the response of ER and salt stress in Medicago. MfSTMIR expression was induced by salt and tunicamycin (Tm). mtstmir loss-of-function mutants displayed impaired induction of the ER stress-responsive genes BiP1/2 and BiP3 under Tm treatment and sensitivity to salt stress. MfSTMIR promoted the degradation of a known ERAD substrate, CPY*. MfSTMIR interacted with the ERAD-associated ubiquitin-conjugating enzyme MtUBC32 and Sec61-translocon subunit MtSec61γ. MfSTMIR did not affect MtSec61γ protein stability. Our results suggest that the plant-specific E3 ligase MfSTMIR participates in the ERAD pathway by interacting with MtUBC32 and MtSec61γ to relieve ER stress during salt stress.
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Affiliation(s)
- Rongxue Zhang
- State Key Laboratory of AgrobiotechnologyCollege of Biological SciencesChina Agricultural UniversityBeijing100193China
- Crop Research Institute of Tianjin Academy of Agricultural SciencesTianjin300384China
| | - Hong Chen
- State Key Laboratory of AgrobiotechnologyCollege of Biological SciencesChina Agricultural UniversityBeijing100193China
| | - Mei Duan
- State Key Laboratory of AgrobiotechnologyCollege of Biological SciencesChina Agricultural UniversityBeijing100193China
| | - Fugui Zhu
- State Key Laboratory of AgrobiotechnologyCollege of Biological SciencesChina Agricultural UniversityBeijing100193China
| | - Jiangqi Wen
- Plant Biology DivisionSamuel Roberts Noble Research InstituteArdmoreOklahoma73401USA
| | - Jiangli Dong
- State Key Laboratory of AgrobiotechnologyCollege of Biological SciencesChina Agricultural UniversityBeijing100193China
| | - Tao Wang
- State Key Laboratory of AgrobiotechnologyCollege of Biological SciencesChina Agricultural UniversityBeijing100193China
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27
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Ahn MY, Oh TR, Seo DH, Kim JH, Cho NH, Kim WT. Arabidopsis group XIV ubiquitin-conjugating enzymes AtUBC32, AtUBC33, and AtUBC34 play negative roles in drought stress response. JOURNAL OF PLANT PHYSIOLOGY 2018; 230:73-79. [PMID: 30193177 DOI: 10.1016/j.jplph.2018.08.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/27/2018] [Accepted: 08/27/2018] [Indexed: 05/06/2023]
Abstract
AtUBC32, AtUBC33, and AtUBC34 comprise Arabidopsis group XIV E2 ubiquitin-conjugating enzymes. Yeast two-hybrid, in vitro pull-down, and bimolecular fluorescence complementation assays revealed that group XIV E2s are interacting partners of the U-box-type E3 ligase PUB19, a negative regulator of drought stress response. These three AtUBCs are co-localized with PUB19 to the punctae-like structures, most of which reside on the endoplasmic reticulum membrane of tobacco leaf cells. Suppression of AtUBC32, AtUBC33, and AtUBC34 resulted in increased abscisic acid-mediated stomatal closure and tolerance to drought stress. These results indicate that Arabidopsis group XIV E2s play negative roles in drought stress response.
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Affiliation(s)
- Min Yong Ahn
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Tae Rin Oh
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Dong Hye Seo
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Jong Hum Kim
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Na Hyun Cho
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Woo Taek Kim
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea.
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28
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Tan X, He X, Fan Z. Upregulation of HRD1 promotes cell migration and invasion in colon cancer. Mol Cell Biochem 2018; 454:1-9. [PMID: 30306455 DOI: 10.1007/s11010-018-3447-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/01/2018] [Indexed: 12/21/2022]
Abstract
3-Hydroxy-3-methylglutaryl reductase degradation (HRD1) is an E3 ubiquitin ligase that functions by promoting degradation of misfolded proteins in processes such as embryogenesis and rheumatoid arthritis. However, little is known about the role of HRD1 in cancer. The aim of the present study was to investigate the expression pattern and functions of HRD1 in human colon cancer (CC). We found that HRD1 expression was increased significantly in human CC tissues, and its overexpression was associated with TNM stage, tumor differentiation, tumor invasive depth, and distant metastasis. Knockdown of HRD1 using small hairpin (sh) RNA plasmid significantly inhibited CC cell migration and invasion. Furthermore, the silencing of HRD1 decreased the expression of MMP-2 and MMP-9, which is critical for CC cell migration and invasion. Taken together, these results revealed that HRD1 is overexpressed in CC and promotes migration and invasion of CC cells. Inhibition of HRD1 may be considered as an effective anti-CC strategy.
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Affiliation(s)
- Xueming Tan
- Department of Digestive Endoscopy Center, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou St., Nanjing, 210029, Jiangsu, People's Republic of China.,Department of Digestive Endoscopy Center, Zhongda Hospital Southest University, Nanjing, 210009, Jiangsu, People's Republic of China
| | - Xiaolu He
- Department of Apheresis, Nanjing Red Cross Blood Center, Nanjing, 210003, Jiangsu, People's Republic of China
| | - Zhining Fan
- Department of Digestive Endoscopy Center, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou St., Nanjing, 210029, Jiangsu, People's Republic of China.
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29
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Park JH, Kang CH, Nawkar GM, Lee ES, Paeng SK, Chae HB, Chi YH, Kim WY, Yun DJ, Lee SY. EMR, a cytosolic-abundant ring finger E3 ligase, mediates ER-associated protein degradation in Arabidopsis. THE NEW PHYTOLOGIST 2018; 220:163-177. [PMID: 29932218 DOI: 10.1111/nph.15279] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 05/18/2018] [Indexed: 05/16/2023]
Abstract
Investigation of the endoplasmic reticulum-associated degradation (ERAD) system in plants led to the identification of ERAD-mediating RING finger protein (EMR) as a plant-specific ERAD E3 ligase from Arabidopsis. EMR was significantly up-regulated under endoplasmic reticulum (ER) stress conditions. The EMR protein purified from bacteria displayed high E3 ligase activity, and tobacco leaf-produced EMR mediated mildew resistance locus O-12 (MLO12) degradation in a proteasome-dependent manner. Subcellular localization and coimmunoprecipitation analyses showed that EMR forms a complex with ubiquitin-conjugating enzyme 32 (UBC32) as a cytosolic interaction partner. Mutation of EMR and RNA interference (RNAi) increased the tolerance of plants to ER stress. EMR RNAi in the bri1-5 background led to partial recovery of the brassinosteroid (BR)-insensitive phenotypes as compared with the original mutant plants and increased ER stress tolerance. The presented results suggest that EMR is involved in the plant ERAD system that affects BR signaling under ER stress conditions as a novel Arabidopsis ring finger E3 ligase mainly present in cytosol while the previously identified ERAD E3 components are typically membrane-bound proteins.
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Affiliation(s)
- Joung Hun Park
- Division of Applied Life Sciences (BK21+) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Chang Ho Kang
- Division of Applied Life Sciences (BK21+) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Ganesh M Nawkar
- Division of Applied Life Sciences (BK21+) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Eun Seon Lee
- Division of Applied Life Sciences (BK21+) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Seol Ki Paeng
- Division of Applied Life Sciences (BK21+) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Ho Byoung Chae
- Division of Applied Life Sciences (BK21+) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Yong Hun Chi
- Division of Applied Life Sciences (BK21+) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Woe Yeon Kim
- Division of Applied Life Sciences (BK21+) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Dae-Jin Yun
- Department of Biomedical Science and Engineering, Konkuk University, Seoul, 05029, Korea
| | - Sang Yeol Lee
- Division of Applied Life Sciences (BK21+) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
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30
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Abstract
The endoplasmic reticulum (ER) is the site of maturation for roughly one-third of all cellular proteins. ER-resident molecular chaperones and folding catalysts promote folding and assembly in a diverse set of newly synthesized proteins. Because these processes are error-prone, all eukaryotic cells have a quality-control system in place that constantly monitors the proteins and decides their fate. Proteins with potentially harmful nonnative conformations are subjected to assisted folding or degraded. Persistent folding-defective proteins are distinguished from folding intermediates and targeted for degradation by a specific process involving clearance from the ER. Although the basic principles of these processes appear conserved from yeast to animals and plants, there are distinct differences in the ER-associated degradation of misfolded glycoproteins. The general importance of ER quality-control events is underscored by their involvement in the biogenesis of diverse cell surface receptors and their crucial maintenance of protein homeostasis under diverse stress conditions.
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Affiliation(s)
- Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria;
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31
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Shin Y, Vavra U, Veit C, Strasser R. The glycan-dependent ERAD machinery degrades topologically diverse misfolded proteins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:246-259. [PMID: 29396984 PMCID: PMC5900737 DOI: 10.1111/tpj.13851] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 12/21/2017] [Accepted: 01/17/2018] [Indexed: 05/18/2023]
Abstract
Many soluble and integral membrane proteins fold in the endoplasmic reticulum (ER) with the help of chaperones and folding factors. Despite these efforts, protein folding is intrinsically error prone and amino acid changes, alterations in post-translational modifications or cellular stress can cause protein misfolding. Folding-defective non-native proteins are cleared from the ER and typically undergo ER-associated degradation (ERAD). Here, we investigated whether different misfolded glycoproteins require the same set of ERAD factors and are directed to HRD1 complex-mediated degradation in plants. We generated a series of glycoprotein ERAD substrates harboring a misfolded domain from Arabidopsis STRUBBELIG or the BRASSINOSTEROID INSENSITVE 1 receptor fused to different membrane anchoring regions. We show that single pass and multispanning ERAD substrates are subjected to glycan-dependent degradation by the HRD1 complex. However, the presence of a powerful ER exit signal in the multispanning ERAD substrates causes competition with ER quality control and targeting of misfolded glycoproteins to the vacuole. Our results demonstrate that the same machinery is used for degradation of topologically different misfolded glycoproteins in the ER of plants.
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Affiliation(s)
- Yun‐Ji Shin
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life SciencesMuthgasse 18ViennaA‐1190Austria
| | - Ulrike Vavra
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life SciencesMuthgasse 18ViennaA‐1190Austria
| | - Christiane Veit
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life SciencesMuthgasse 18ViennaA‐1190Austria
| | - Richard Strasser
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life SciencesMuthgasse 18ViennaA‐1190Austria
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32
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Schulz J, Avci D, Queisser MA, Gutschmidt A, Dreher LS, Fenech EJ, Volkmar N, Hayashi Y, Hoppe T, Christianson JC. Conserved cytoplasmic domains promote Hrd1 ubiquitin ligase complex formation for ER-associated degradation (ERAD). J Cell Sci 2017; 130:3322-3335. [PMID: 28827405 DOI: 10.1242/jcs.206847] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/16/2017] [Indexed: 12/20/2022] Open
Abstract
The mammalian ubiquitin ligase Hrd1 is the central component of a complex facilitating degradation of misfolded proteins during the ubiquitin-proteasome-dependent process of ER-associated degradation (ERAD). Hrd1 associates with cofactors to execute ERAD, but their roles and how they assemble with Hrd1 are not well understood. Here, we identify crucial cofactor interaction domains within Hrd1 and report a previously unrecognised evolutionarily conserved segment within the intrinsically disordered cytoplasmic domain of Hrd1 (termed the HAF-H domain), which engages complementary segments in the cofactors FAM8A1 and Herp (also known as HERPUD1). This domain is required by Hrd1 to interact with both FAM8A1 and Herp, as well as to assemble higher-order Hrd1 complexes. FAM8A1 enhances binding of Herp to Hrd1, an interaction that is required for ERAD. Our findings support a model of Hrd1 complex formation, where the Hrd1 cytoplasmic domain and FAM8A1 have a central role in the assembly and activity of this ERAD machinery.
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Affiliation(s)
- Jasmin Schulz
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Dönem Avci
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Markus A Queisser
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Aljona Gutschmidt
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - Lena-Sophie Dreher
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - Emma J Fenech
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Norbert Volkmar
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Yuki Hayashi
- Department of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
| | - Thorsten Hoppe
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - John C Christianson
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, UK
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Wang X, Komatsu S. Proteomic Analysis of Calcium Effects on Soybean Root Tip under Flooding and Drought Stresses. PLANT & CELL PHYSIOLOGY 2017; 58:1405-1420. [PMID: 28586431 DOI: 10.1093/pcp/pcx078] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/18/2017] [Indexed: 06/07/2023]
Abstract
Flooding and drought are disadvantageous environmental conditions that induce cytosolic calcium in soybean. To explore the effects of flooding- and drought-induced increases in calcium, a gel-free/label-free proteomic analysis was performed. Cytosolic calcium was decreased by blocking calcium channels in the endoplasmic reticulum (ER) and plasma membrane under both stresses. Calnexin, protein disulfide isomerase, heat shock proteins and thioredoxin were predominantly affected as the ER proteins in response to calcium, and ER-associated degradation-related proteins of HCP-like superfamily protein were up-regulated under stress exposure and then down-regulated. Glycolysis, fermentation, the tricarboxylic acid cycle and amino acid metabolism were mainly induced as the types of cellular metabolism in response to calcium under both stresses. Pyruvate decarboxylase was increased and decreased under flooding and drought, respectively, and was further decreased by the reduction of cytosolic calcium; however, it was recovered by exogenous calcium under both stresses. Furthermore, pyruvate decarboxylase activity was increased under flooding, but decreased under drought. These results suggest that calcium is involved in protein folding in the ER, and ER-associated degradation might alleviate ER stress during the early stage of both stresses. Furthermore, calcium appears to modify energy metabolism, and pyruvate decarboxylase may be a key enzyme in this process under flooding and drought.
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Affiliation(s)
- Xin Wang
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan
- National Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba 305-8518, Japan
| | - Setsuko Komatsu
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan
- National Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba 305-8518, Japan
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Chen Q, Liu R, Wang Q, Xie Q. ERAD Tuning of the HRD1 Complex Component AtOS9 Is Modulated by an ER-Bound E2, UBC32. MOLECULAR PLANT 2017; 10:891-894. [PMID: 28040559 DOI: 10.1016/j.molp.2016.12.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 12/08/2016] [Accepted: 12/20/2016] [Indexed: 06/06/2023]
Affiliation(s)
- Qian Chen
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, P. R. China; The Faculty of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Ruijun Liu
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, P. R. China; The Faculty of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qian Wang
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, P. R. China; The Faculty of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qi Xie
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, P. R. China; The Faculty of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
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Plant Virus Infection and the Ubiquitin Proteasome Machinery: Arms Race along the Endoplasmic Reticulum. Viruses 2016; 8:v8110314. [PMID: 27869775 PMCID: PMC5127028 DOI: 10.3390/v8110314] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 09/29/2016] [Accepted: 11/08/2016] [Indexed: 12/24/2022] Open
Abstract
The endoplasmic reticulum (ER) is central to plant virus replication, translation, maturation, and egress. Ubiquitin modification of ER associated cellular and viral proteins, alongside the actions of the 26S proteasome, are vital for the regulation of infection. Viruses can arrogate ER associated ubiquitination as well as cytosolic ubiquitin ligases with the purpose of directing the ubiquitin proteasome system (UPS) to new targets. Such targets include necessary modification of viral proteins which may stabilize certain complexes, or modification of Argonaute to suppress gene silencing. The UPS machinery also contributes to the regulation of effector triggered immunity pattern recognition receptor immunity. Combining the results of unrelated studies, many positive strand RNA plant viruses appear to interact with cytosolic Ub-ligases to provide novel avenues for controlling the deleterious consequences of disease. Viral interactions with the UPS serve to regulate virus infection in a manner that promotes replication and movement, but also modulates the levels of RNA accumulation to ensure successful biotrophic interactions. In other instances, the UPS plays a central role in cellular immunity. These opposing roles are made evident by contrasting studies where knockout mutations in the UPS can either hamper viruses or lead to more aggressive diseases. Understanding how viruses manipulate ER associated post-translational machineries to better manage virus–host interactions will provide new targets for crop improvement.
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