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Wang H, Meng L, Otaegi-Ugartemendia S, Condezo GN, Blanc-Mathieu R, Stokke R, Langvad MR, Brandt D, Kalinowski J, Dahle H, San Martín C, Ogata H, Sandaa RA. Haptophyte-infecting viruses change the genome condensing proteins of dinoflagellates. Commun Biol 2025; 8:510. [PMID: 40155463 PMCID: PMC11953307 DOI: 10.1038/s42003-025-07905-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 03/10/2025] [Indexed: 04/01/2025] Open
Abstract
Giant viruses are extraordinary members of the virosphere due to their structural complexity and high diversity in gene content. Haptophytes are ecologically important primary producers in the ocean, and all known viruses that infect haptophytes are giant viruses. However, little is known about the specifics of their infection cycles and the responses they trigger in their host cells. Our in-depth electron microscopic, phylogenomic and virion proteomic analyses of two haptophyte-infecting giant viruses, Haptolina ericina virus RF02 (HeV RF02) and Prymnesium kappa virus RF02 (PkV RF02), unravel their large capacity for host manipulation and arsenals that function during the infection cycle from virus entry to release. The virus infection induces significant morphological changes in the host cell that is manipulated to build a virus proliferation factory. Both viruses' genomes encode a putative nucleoprotein (dinoflagellate/viral nucleoprotein; DVNP), which was also found in the virion proteome of PkV RF02. Phylogenetic analysis suggests that DVNPs are widespread in marine giant metaviromes. Furthermore, the analysis shows that the dinoflagellate homologues were possibly acquired from viruses of the order Imitervirales. These findings enhance our understanding of how viruses impact the biology of microalgae, providing insights into evolutionary biology, ecosystem dynamics, and nutrient cycling in the ocean.
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Affiliation(s)
- Haina Wang
- Department of Biological Sciences, University of Bergen, Bergen, Norway.
| | - Lingjie Meng
- Institute for Chemical Research, Kyoto University, Uji, Japan
| | | | | | | | - Runar Stokke
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
| | | | - David Brandt
- Bielefeld University, CeBiTec, Bielefeld, Germany
| | | | - Håkon Dahle
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | | | - Hiroyuki Ogata
- Institute for Chemical Research, Kyoto University, Uji, Japan
| | - Ruth-Anne Sandaa
- Department of Biological Sciences, University of Bergen, Bergen, Norway.
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2
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Liu X, Guo N, Li S, Duan M, Wang G, Zong M, Han S, Wu Z, Liu F, Zhang J. Characterization of the Bax Inhibitor-1 Family in Cauliflower and Functional Analysis of BobBIL4. Int J Mol Sci 2024; 25:9562. [PMID: 39273509 PMCID: PMC11395134 DOI: 10.3390/ijms25179562] [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: 07/18/2024] [Revised: 08/22/2024] [Accepted: 08/26/2024] [Indexed: 09/15/2024] Open
Abstract
The Bax inhibitor-1 (BI-1) gene family, which is important for plant growth, development, and stress tolerance, remains largely unexplored in cauliflower. In this study, we identified and characterized cauliflower BI-1 family genes. Based on aligned homologous sequences and collinearity with Arabidopsis genes, we identified nine cauliflower BI-1 genes, which encode proteins that varied in length, molecular weight, isoelectric point, and predicted subcellular localization, including the Golgi apparatus, plasma membrane, and various compartments within the chloroplast. Phylogenetic analyses detected evolutionary conservation and divergence among these genes. Ten structural motifs were identified, with Motif 5 found to be crucial for inhibiting apoptosis. According to the cis-regulatory elements in their promoters, these genes likely influence hormone signaling and stress responses. Expression profiles among tissues highlighted the functional diversity of these genes, with particularly high expression levels observed in the silique and root. Focusing on BobBIL4, we investigated its role in brassinosteroid (BR)-mediated root development and salt stress tolerance. BobBIL4 expression levels increased in response to BR and salt treatments. The functional characterization of this gene in Arabidopsis revealed that it enhances root growth and salinity tolerance. These findings provide insights into BI-1 gene functions in cauliflower while also highlighting the potential utility of BobBIL4 for improving crop stress resistance.
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Affiliation(s)
- Xin Liu
- College of Life Science, Sichuan Agricultural University, No. 46, Xinkang Road, Ya’an 625014, China; (X.L.); (S.L.)
- State Key Laboratory of Vegetable Biobreeding, National Engineering Research Center for Vegetables, Beijing Key Laboratory of Vegetable Germplasms Improvement, Key Laboratory of Biology and Genetics Improvement of Horticultural Crops (North China), Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing 100097, China; (N.G.); (M.D.); (G.W.); (M.Z.); (S.H.); (Z.W.)
| | - Ning Guo
- State Key Laboratory of Vegetable Biobreeding, National Engineering Research Center for Vegetables, Beijing Key Laboratory of Vegetable Germplasms Improvement, Key Laboratory of Biology and Genetics Improvement of Horticultural Crops (North China), Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing 100097, China; (N.G.); (M.D.); (G.W.); (M.Z.); (S.H.); (Z.W.)
| | - Shasha Li
- College of Life Science, Sichuan Agricultural University, No. 46, Xinkang Road, Ya’an 625014, China; (X.L.); (S.L.)
- State Key Laboratory of Vegetable Biobreeding, National Engineering Research Center for Vegetables, Beijing Key Laboratory of Vegetable Germplasms Improvement, Key Laboratory of Biology and Genetics Improvement of Horticultural Crops (North China), Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing 100097, China; (N.G.); (M.D.); (G.W.); (M.Z.); (S.H.); (Z.W.)
| | - Mengmeng Duan
- State Key Laboratory of Vegetable Biobreeding, National Engineering Research Center for Vegetables, Beijing Key Laboratory of Vegetable Germplasms Improvement, Key Laboratory of Biology and Genetics Improvement of Horticultural Crops (North China), Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing 100097, China; (N.G.); (M.D.); (G.W.); (M.Z.); (S.H.); (Z.W.)
| | - Guixiang Wang
- State Key Laboratory of Vegetable Biobreeding, National Engineering Research Center for Vegetables, Beijing Key Laboratory of Vegetable Germplasms Improvement, Key Laboratory of Biology and Genetics Improvement of Horticultural Crops (North China), Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing 100097, China; (N.G.); (M.D.); (G.W.); (M.Z.); (S.H.); (Z.W.)
| | - Mei Zong
- State Key Laboratory of Vegetable Biobreeding, National Engineering Research Center for Vegetables, Beijing Key Laboratory of Vegetable Germplasms Improvement, Key Laboratory of Biology and Genetics Improvement of Horticultural Crops (North China), Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing 100097, China; (N.G.); (M.D.); (G.W.); (M.Z.); (S.H.); (Z.W.)
| | - Shuo Han
- State Key Laboratory of Vegetable Biobreeding, National Engineering Research Center for Vegetables, Beijing Key Laboratory of Vegetable Germplasms Improvement, Key Laboratory of Biology and Genetics Improvement of Horticultural Crops (North China), Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing 100097, China; (N.G.); (M.D.); (G.W.); (M.Z.); (S.H.); (Z.W.)
| | - Zihan Wu
- State Key Laboratory of Vegetable Biobreeding, National Engineering Research Center for Vegetables, Beijing Key Laboratory of Vegetable Germplasms Improvement, Key Laboratory of Biology and Genetics Improvement of Horticultural Crops (North China), Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing 100097, China; (N.G.); (M.D.); (G.W.); (M.Z.); (S.H.); (Z.W.)
| | - Fan Liu
- State Key Laboratory of Vegetable Biobreeding, National Engineering Research Center for Vegetables, Beijing Key Laboratory of Vegetable Germplasms Improvement, Key Laboratory of Biology and Genetics Improvement of Horticultural Crops (North China), Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing 100097, China; (N.G.); (M.D.); (G.W.); (M.Z.); (S.H.); (Z.W.)
| | - Junjie Zhang
- College of Life Science, Sichuan Agricultural University, No. 46, Xinkang Road, Ya’an 625014, China; (X.L.); (S.L.)
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3
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Rehman S, Ahmad Z, Ramakrishnan M, Kalendar R, Zhuge Q. Regulation of plant epigenetic memory in response to cold and heat stress: towards climate resilient agriculture. Funct Integr Genomics 2023; 23:298. [PMID: 37700098 DOI: 10.1007/s10142-023-01219-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 08/18/2023] [Accepted: 08/23/2023] [Indexed: 09/14/2023]
Abstract
Plants have evolved to adapt and grow in hot and cold climatic conditions. Some also adapt to daily and seasonal temperature changes. Epigenetic modifications play an important role in regulating plant tolerance under such conditions. DNA methylation and post-translational modifications of histone proteins influence gene expression during plant developmental stages and under stress conditions, including cold and heat stress. While short-term modifications are common, some modifications may persist and result in stress memory that can be inherited by subsequent generations. Understanding the mechanisms of epigenomes responding to stress and the factors that trigger stress memory is crucial for developing climate-resilient agriculture, but such an integrated view is currently limited. This review focuses on the plant epigenetic stress memory during cold and heat stress. It also discusses the potential of machine learning to modify stress memory through epigenetics to develop climate-resilient crops.
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Affiliation(s)
- Shamsur Rehman
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics and Biotechnology, College of Biology and the Environment, Nanjing Forestry University, Ministry of Education, Nanjing, China
| | - Zishan Ahmad
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing, 210037, China
| | - Muthusamy Ramakrishnan
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing, 210037, China
| | - Ruslan Kalendar
- Helsinki Institute of Life Science HiLIFE, Biocenter 3, Viikinkaari 1, FI-00014 University of Helsinki, Helsinki, Finland.
- Center for Life Sciences, National Laboratory Astana, Nazarbayev University, Astana, Kazakhstan.
| | - Qiang Zhuge
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics and Biotechnology, College of Biology and the Environment, Nanjing Forestry University, Ministry of Education, Nanjing, China.
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4
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The Rice Malectin Regulates Plant Cell Death and Disease Resistance by Participating in Glycoprotein Quality Control. Int J Mol Sci 2022; 23:ijms23105819. [PMID: 35628631 PMCID: PMC9144812 DOI: 10.3390/ijms23105819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 11/16/2022] Open
Abstract
In animals, malectin is well known to play an essential role in endoplasmic reticulum quality control (ERQC) by interacting with ribophorin I, one unit of the oligosaccharyltransferase (OST) complex. However, the functions of malectin in plants remain largely unknown. Here, we demonstrate the rice OsMLD1 is an ER- and Golgi-associated malectin protein and physically interacts with rice homolog of ribophorin I (OsRpn1), and its disruption leads to spontaneous lesion mimic lesions, enhanced disease resistance, and prolonged ER stress. In addition, there are many more N-glycosites and N-glycoproteins identified from the mld1 mutant than wildtype. Furthermore, OsSERK1 and OsSERK2, which have more N-glycosites in mld1, were demonstrated to interact with OsMLD1. OsMLD1 can suppress OsSERK1- or OsSERK2-induced cell death. Thus, OsMLD1 may play a similar role to its mammalian homologs in glycoprotein quality control, thereby regulating cell death and immunity of rice, which uncovers the function of malectin in plants.
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Yang Y, Liu X, Zhang W, Qian Q, Zhou L, Liu S, Li Y, Hou X. Stress response proteins NRP1 and NRP2 are pro-survival factors that inhibit cell death during ER stress. PLANT PHYSIOLOGY 2021; 187:1414-1427. [PMID: 34618053 PMCID: PMC8566283 DOI: 10.1093/plphys/kiab335] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 06/24/2021] [Indexed: 05/12/2023]
Abstract
Environmental stresses cause an increased number of unfolded or misfolded proteins to accumulate in the endoplasmic reticulum (ER), resulting in ER stress. To restore ER homeostasis and survive, plants initiate an orchestrated signaling pathway known as the unfolded protein response (UPR). Asparagine-rich protein (NRP) 1 and NRP2, two homologous proteins harboring a Development and Cell Death domain, are associated with various stress responses in Arabidopsis (Arabidopsis thaliana), but the relevant molecular mechanism remains obscure. Here, we show that NRP1 and NRP2 act as key pro-survival factors during the ER stress response and that they inhibit cell death. Loss-of-function of NRP1 and NRP2 results in decreased tolerance to the ER stress inducer tunicamycin (TM), accelerating cell death. NRP2 is constitutively expressed while NRP1 is induced in plants under ER stress. In Arabidopsis, basic leucine zipper protein (bZIP) 28 and bZIP60 are important transcription factors in the UPR that activates the expression of many ER stress-related genes. Notably, under ER stress, bZIP60 activates NRP1 by directly binding to the UPRE-I element in the NRP1 promoter. These findings reveal a pro-survival strategy in plants wherein the bZIP60-NRPs cascade suppresses cell death signal transmission, improving survival under adverse conditions.
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Affiliation(s)
- Yuhua Yang
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Xu Liu
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Wenbin Zhang
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Qian Qian
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Limeng Zhou
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Shu Liu
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yuge Li
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Xingliang Hou
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou 510650, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
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6
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Cai J, Wei S, Lu Y, Wu Z, Qin Q, Jian J. Bax inhibitor-1 from orange spotted grouper, Epinephelus coioides involved in viral infection. FISH & SHELLFISH IMMUNOLOGY 2018; 78:91-99. [PMID: 29679759 DOI: 10.1016/j.fsi.2018.04.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/05/2018] [Accepted: 04/07/2018] [Indexed: 06/08/2023]
Abstract
Bax inhibitor-1 (BI-1) is a conserved anti-apoptotic protein that suppresses endoplasmic reticulum (ER) stress-induced cell death. However, the function of fish BI-1 is not quite clear. In the present study, a bi-1 homolog (Ecbi-1) from orange spotted grouper, Epinephelus coioides was identified and its roles in viral infection were investigated. EcBI-1 encoded 237 amino acids protein, contained six transmembrane regions and a conservative C-terminus motif. Ecbi-1 predominantly expressed in kidney and spleen of healthy grouper. After SGIV stimulation, Ecbi-1 transcript was significantly increased in vitro. Subcellular localization analysis revealed that EcBI-1 was localized throughout the cytoplasm and co-localized with ER. Furthermore, overexpression of EcBI-1 suppressed SGIV infection induced cell death, caspase-3 activity and viral genes transcription. And C-terminus motif was critical for regulation roles of EcBI-1 during SGIV infection. In addition, EcBI-1 could interact with EcBNIP3 in vitro. Together, our data firstly demonstrated that fish BI-1 play important roles in response to viral infection.
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Affiliation(s)
- Jia Cai
- College of Fishery, Guangdong Ocean University, Zhanjiang 524088, PR China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524088, PR China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang 524088, PR China
| | - Shina Wei
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, PR China
| | - Yishan Lu
- College of Fishery, Guangdong Ocean University, Zhanjiang 524088, PR China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524088, PR China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang 524088, PR China
| | - Zaohe Wu
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524088, PR China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang 524088, PR China
| | - Qiwei Qin
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, PR China.
| | - Jichang Jian
- College of Fishery, Guangdong Ocean University, Zhanjiang 524088, PR China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524088, PR China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang 524088, PR China.
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7
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Gaguancela OA, Zúñiga LP, Arias AV, Halterman D, Flores FJ, Johansen IE, Wang A, Yamaji Y, Verchot J. The IRE1/bZIP60 Pathway and Bax Inhibitor 1 Suppress Systemic Accumulation of Potyviruses and Potexviruses in Arabidopsis and Nicotiana benthamiana Plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:750-766. [PMID: 27578623 DOI: 10.1094/mpmi-07-16-0147-r] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The inositol requiring enzyme (IRE1) is an endoplasmic reticulum (ER) stress sensor. When activated, it splices the bZIP60 mRNA, producing a truncated transcription factor that upregulates genes involved in the unfolded protein response. Bax inhibitor 1 (BI-1) is another ER stress sensor that regulates cell death in response to environmental assaults. The potyvirus 6K2 and potexvirus TGB3 proteins are known to reside in the ER, serving, respectively, as anchors for the viral replicase and movement protein complex. This study used green fluorescent protein (GFP)-tagged Turnip mosaic virus (TuMV), Plantago asiatica mosaic virus (PlAMV), Potato virus Y (PVY), and Potato virus X (PVX) to determine that the IRE1/bZIP60 pathway and BI-1 machinery are induced early in virus infection in Arabidopsis thaliana, Nicotiana benthamiana, and Solanum tuberosum. Agrodelivery of only the potyvirus 6K2 or TGB3 genes into plant cells activated bZIP60 and BI-1 expression in Arabidopsis thaliana, N. benthamiana, and S. tuberosum. Homozygous ire1a-2, ire1b-4, and ire1a-2/ire1b-4 mutant Arabidopsis plants were inoculated with TuMV-GFP or PlAMV-GFP. PlAMV accumulates to a higher level in ire1a-2 or ire1a-2/ire1b-4 mutant plants than in ire1b-4 or wild-type plants. TuMV-GFP accumulates to a higher level in ire1a-2, ire1b-4, or ire1a-2/ire1b-4 compared with wild-type plants, suggesting that both isoforms contribute to TuMV-GFP infection. Gene silencing was used to knock down bZIP60 and BI-1 expression in N. benthamiana. PVX-GFP and PVY-GFP accumulation was significantly elevated in these silenced plants compared with control plants. This study demonstrates that two ER stress pathways, namely IRE1/bZIP60 and the BI-1 pathway, limit systemic accumulation of potyvirus and potexvirus infection. Silencing BI-1 expression also resulted in systemic necrosis. These data suggest that ER stress-activated pathways, led by IRE1 and BI-1, respond to invading potyvirus and potexviruses to restrict virus infection and enable physiological changes enabling plants to tolerate virus assault.
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Affiliation(s)
- Omar Arias Gaguancela
- 1 Department of Entomology & Plant Pathology, Oklahoma State University, Stillwater, OK 74078, U.S.A
| | - Lizbeth Peña Zúñiga
- 1 Department of Entomology & Plant Pathology, Oklahoma State University, Stillwater, OK 74078, U.S.A
| | - Alexis Vela Arias
- 2 Departamento de Ciencias de la Vida y la Agricultura, Universidad de las Fuerzas Armadas-ESPE, Av. General Rumiñahui s/n, Sangolquí, Pichincha, Ecuador
| | - Dennis Halterman
- 3 Agricultural Research Service, Vegetable Crops Research Unit, U.S. Department of Agriculture ARS, Madison, WI, U.S.A
| | - Francisco Javier Flores
- 2 Departamento de Ciencias de la Vida y la Agricultura, Universidad de las Fuerzas Armadas-ESPE, Av. General Rumiñahui s/n, Sangolquí, Pichincha, Ecuador
| | - Ida Elisabeth Johansen
- 4 Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Aiming Wang
- 5 Southern Crop Protection and Food Research Centre, AAFC, 1391 Sandford Street, London, Ontario N5V 4T3, Canada; and
| | - Yasuyuki Yamaji
- 6 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Jeanmarie Verchot
- 1 Department of Entomology & Plant Pathology, Oklahoma State University, Stillwater, OK 74078, U.S.A
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8
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Yang X, Srivastava R, Howell SH, Bassham DC. Activation of autophagy by unfolded proteins during endoplasmic reticulum stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:83-95. [PMID: 26616142 DOI: 10.1111/tpj.13091] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 11/18/2015] [Accepted: 11/20/2015] [Indexed: 05/20/2023]
Abstract
Endoplasmic reticulum stress is defined as the accumulation of unfolded proteins in the endoplasmic reticulum, and is caused by conditions such as heat or agents that cause endoplasmic reticulum stress, including tunicamycin and dithiothreitol. Autophagy, a major pathway for degradation of macromolecules in the vacuole, is activated by these stress agents in a manner dependent on inositol-requiring enzyme 1b (IRE1b), and delivers endoplasmic reticulum fragments to the vacuole for degradation. In this study, we examined the mechanism for activation of autophagy during endoplasmic reticulum stress in Arabidopsis thaliana. The chemical chaperones sodium 4-phenylbutyrate and tauroursodeoxycholic acid were found to reduce tunicamycin- or dithiothreitol-induced autophagy, but not autophagy caused by unrelated stresses. Similarly, over-expression of BINDING IMMUNOGLOBULIN PROTEIN (BIP), encoding a heat shock protein 70 (HSP70) molecular chaperone, reduced autophagy. Autophagy activated by heat stress was also found to be partially dependent on IRE1b and to be inhibited by sodium 4-phenylbutyrate, suggesting that heat-induced autophagy is due to accumulation of unfolded proteins in the endoplasmic reticulum. Expression in Arabidopsis of the misfolded protein mimics zeolin or a mutated form of carboxypeptidase Y (CPY*) also induced autophagy in an IRE1b-dependent manner. Moreover, zeolin and CPY* partially co-localized with the autophagic body marker GFP-ATG8e, indicating delivery to the vacuole by autophagy. We conclude that accumulation of unfolded proteins in the endoplasmic reticulum is a trigger for autophagy under conditions that cause endoplasmic reticulum stress.
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Affiliation(s)
- Xiaochen Yang
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, 50011, USA
- Interdepartmental Plant Biology Program, Iowa State University, Ames, IA, 50011, USA
| | - Renu Srivastava
- Plant Sciences Institute, Iowa State University, Ames, IA, 50011, USA
| | - Stephen H Howell
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, 50011, USA
- Interdepartmental Plant Biology Program, Iowa State University, Ames, IA, 50011, USA
- Plant Sciences Institute, Iowa State University, Ames, IA, 50011, USA
| | - Diane C Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, 50011, USA
- Interdepartmental Plant Biology Program, Iowa State University, Ames, IA, 50011, USA
- Plant Sciences Institute, Iowa State University, Ames, IA, 50011, USA
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9
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Kim Y, Wang M, Bai Y, Zeng Z, Guo F, Han N, Bian H, Wang J, Pan J, Zhu M. Bcl-2 suppresses activation of VPEs by inhibiting cytosolic Ca²⁺ level with elevated K⁺ efflux in NaCl-induced PCD in rice. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 80:168-75. [PMID: 24787501 DOI: 10.1016/j.plaphy.2014.04.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 04/05/2014] [Indexed: 05/21/2023]
Abstract
Bcl-2 is one of the most important antiapoptotic members in mammals and prevents many forms of apoptosis in a variety of cell types. Our previous study revealed that overexpression of Bcl-2 significantly suppressed H2O2/NaCl-induced programmed cell death via inhibiting the transcriptional activation of OsVPE2 and OsVPE3 in transgenic rice. However, Ca(2+) and K(+) homeostasis of this process remains largely unknown. In the present study, we investigate whether nonselective cation channels (NSCC) blockers affect Bcl-2 function in rice under salt stress and how Bcl-2 affects ion homeostasis in salt stress-induced PCD. The results showed that overexpression of Bcl-2 significantly decreased transient elevations in the cytosolic Ca(2+) levels, inhibited NaCl-induced K(+) efflux but not H(+) efflux across the plasma membrane, and further suppressed the expression levels of OsVPE2 and OsVPE3, leading to the inhibition of salt-induced PCD and increase of tolerance to salt stress in transgenic rice. During the NaCl-induced PCD, the effects of a NSCC blocker La(3+) on ion homeostasis and VPEs expression in wild-type were similar to the effects of Bcl-2 overexpression in transgenic line. However, a synergistic effect of Bcl-2 and La(3+) was not obviously detectable. Our results suggested that Bcl-2 played an important role in suppression of NaCl-induced PCD by disruption of ion homeostasis, providing an insight into the mechanistic study of plant VPEs, cytosolic Ca(2+) level and K(+) efflux.
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Affiliation(s)
- Yongho Kim
- Institute of Genetics, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Mingqiang Wang
- Institute of Genetics, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yu Bai
- Institute of Genetics, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhanghui Zeng
- Institute of Genetics, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Fu Guo
- Institute of Genetics, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Ning Han
- Institute of Genetics, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hongwu Bian
- Institute of Genetics, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
| | - Junhui Wang
- Institute of Genetics, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jianwei Pan
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Muyuan Zhu
- Institute of Genetics, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
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Rodriguez-López J, Martínez-Centeno C, Padmanaban A, Guillén G, Olivares JE, Stefano G, Lledías F, Ramos F, Ghabrial SA, Brandizzi F, Rocha-Sosa M, Díaz-Camino C, Sanchez F. Nodulin 22, a novel small heat-shock protein of the endoplasmic reticulum, is linked to the unfolded protein response in common bean. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:18-29. [PMID: 24073881 PMCID: PMC4028047 DOI: 10.1094/mpmi-07-13-0200-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The importance of plant small heat shock proteins (sHsp) in multiple cellular processes has been evidenced by their unusual abundance and diversity; however, little is known about their biological role. Here, we characterized the in vitro chaperone activity and subcellular localization of nodulin 22 of Phaseolus vulgaris (PvNod22; common bean) and explored its cellular function through a virus-induced gene silencing-based reverse genetics approach. We established that PvNod22 facilitated the refolding of a model substrate in vitro, suggesting that it acts as a molecular chaperone in the cell. Through microscopy analyses of PvNod22, we determined its localization in the endoplasmic reticulum (ER). Furthermore, we found that silencing of PvNod22 resulted in necrotic lesions in the aerial organs of P. vulgaris plants cultivated under optimal conditions and that downregulation of PvNod22 activated the ER-unfolded protein response (UPR) and cell death. We also established that PvNod22 expression in wild-type bean plants was modulated by abiotic stress but not by chemicals that trigger the UPR, indicating PvNod22 is not under UPR control. Our results suggest that the ability of PvNod22 to suppress protein aggregation contributes to the maintenance of ER homeostasis, thus preventing the induction of cell death via UPR in response to oxidative stress during plant-microbe interactions.
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11
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Deletion of the human cytomegalovirus US17 gene increases the ratio of genomes per infectious unit and alters regulation of immune and endoplasmic reticulum stress response genes at early and late times after infection. J Virol 2013; 88:2168-82. [PMID: 24335296 DOI: 10.1128/jvi.02704-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Human cytomegalovirus (HCMV) employs numerous strategies to combat, subvert, or co-opt host immunity. One evolutionary strategy for this involves capture of a host gene and then its successive duplication and divergence, forming a family of genes, many of which have immunomodulatory activities. The HCMV US12 family consists of 10 tandemly arranged sequence-related genes in the unique short (US) region of the HCMV genome (US12 to US21). Each gene encodes a protein possessing seven predicted transmembrane domains, patches of sequence similarity with cellular G-protein-coupled receptors, and the Bax inhibitor 1 family of antiapoptotic proteins. We show that one member, US17, plays an important role during virion maturation. Microarray analysis of cells infected with a recombinant HCMV isolate with a US17 deletion (the ΔUS17 mutant virus) revealed blunted host innate and interferon responses at early times after infection (12 h postinfection [hpi]), a pattern opposite that previously seen in the absence of the immunomodulatory tegument protein pp65 (pUL83). Although the ΔUS17 mutant virus produced numbers of infectious particles in fibroblasts equal to the numbers produced by the parental virus, it produced >3-fold more genome-containing noninfectious viral particles and delivered increased amounts of pp65 to newly infected cells. These results suggest that US17 has evolved to control virion composition, to elicit an appropriately balanced host immune response. At later time points (96 hpi), ΔUS17 mutant-infected cells displayed aberrant expression of several host endoplasmic reticulum stress response genes and chaperones, some of which are important for the final stages of virion assembly and egress. Our results suggest that US17 modulates host pathways to enable production of virions that elicit an appropriately balanced host immune response.
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12
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Hoepflinger MC, Reitsamer J, Geretschlaeger AM, Mehlmer N, Tenhaken R. The effect of translationally controlled tumour protein (TCTP) on programmed cell death in plants. BMC PLANT BIOLOGY 2013; 13:135. [PMID: 24040826 PMCID: PMC3847524 DOI: 10.1186/1471-2229-13-135] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 09/12/2013] [Indexed: 05/25/2023]
Abstract
BACKGROUND Translationally controlled tumour protein (TCTP), a well known protein of the animal kingdom, was shown to be a Ca(2+)-binding protein with important functions in many different cellular processes (e.g. protection against stress and apoptosis, cell growth, cell cycle progression, and microtubule organization). However, only little is known about TCTP in plants. Transcript and protein levels of plant TCTPs were shown to be altered by various stress conditions (e.g. cold, salt, draught, aluminium, and pathogen infection), and Arabidopsis thaliana TCTP (AtTCTP) was described as an important regulator of growth. The aim of this study was to further characterize plant TCTP relating to one of its major functions in animals: the protection against cell death. RESULTS We used two different activators of programmed cell death (PCD) in plants: the mammalian pro-apoptotic protein BAX and tunicamycin, an inhibitor of glycosylation and trigger of unfolded protein response (UPR). Over-expression of AtTCTP significantly decreased cell death in tobacco leaf discs in both studies. A (45)Ca overlay assay showed AtTCTP to be a Ca(2+)-binding protein and localization experiments revealed cytosolic distribution of AtTCTP-GFP in Arabidopsis seedlings. CONCLUSIONS Our study showed cytoprotective effects of plant TCTP for the first time. Furthermore, we showed the ability of AtTCTP to bind to Ca(2+) and its cytosolic distribution within the cell. If these results are combined, two putative modes of action can be assumed: 1) AtTCTP acts as Ca(2+) sequester, preventing PCD by reducing cytosolic Ca(2+) levels as described for animals. 2) AtTCTP could directly or indirectly interact with other cytosolic or membrane-bound proteins of the cell death machinery, thereby inhibiting cell death progression. As no homologous proteins of the anti-apoptotic machinery of animals were found in plants, and functional homologues still remain to be elucidated, future work will provide more insight.
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Affiliation(s)
- Marion Christine Hoepflinger
- Department of Cell Biology, Division of Plant Physiology, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria
| | - Johannes Reitsamer
- Department of Cell Biology, Division of Plant Physiology, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria
| | - Anja Maria Geretschlaeger
- Department of Cell Biology, Division of Plant Physiology, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria
| | - Norbert Mehlmer
- Department of Biology I, Botany, LMU Munich, 82152 Martinsried, Germany
| | - Raimund Tenhaken
- Department of Cell Biology, Division of Plant Physiology, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria
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13
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Du ZQ, Lan JF, Weng YD, Zhao XF, Wang JX. BAX inhibitor-1 silencing suppresses white spot syndrome virus replication in red swamp crayfish, Procambarus clarkii. FISH & SHELLFISH IMMUNOLOGY 2013; 35:46-53. [PMID: 23583724 DOI: 10.1016/j.fsi.2013.03.376] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 03/27/2013] [Accepted: 03/28/2013] [Indexed: 06/02/2023]
Abstract
BAX inhibitor-1 (BI-1) was originally described as an anti-apoptotic protein in both animal and plant cells. BI-1 overexpression suppresses ER stress-induced apoptosis in animal cells. Inhibition of BI-1 activity could induce the cell death in mammals and plants. However, the function of BI-1 in crustacean immunity was unclear. In this paper, the full-length cDNA of a BI-1 protein in red swamp crayfish, Procambarus clarkii (PcBI-1) was cloned and its expression profiles in normal and infected crayfish were analyzed. The results showed that PcBI-1 was expressed in hemocytes, heart, hepatopancreas, gills, stomach, and intestines of the crayfish and was upregulated after challenged with Vibrio anguillarum and with white spot syndrome virus (WSSV). To determine the function of PcBI-1 in the innate immunity of the crayfish, the RNA interference against PcBI-1 was performed and the results indicated the hemocyte programmed cell death rate was increased significantly and WSSV replication was declined after PcBI-1 knocked down. Altogether, PcBI-1 plays an anti-apoptotic role, wherein high PcBI-1 expression suppresses programmed cell death, which is beneficial for WSSW replication in crayfish.
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Affiliation(s)
- Zhi-Qiang Du
- The Key Laboratory of Plant Cell Engineering and Germplasm Innovation of Ministry of Education/Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, China
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14
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Ye CM, Chen S, Payton M, Dickman MB, Verchot J. TGBp3 triggers the unfolded protein response and SKP1-dependent programmed cell death. MOLECULAR PLANT PATHOLOGY 2013; 14:241-55. [PMID: 23458484 PMCID: PMC6638746 DOI: 10.1111/mpp.12000] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The Potato virus X (PVX) triple gene block protein 3 (TGBp3), an 8-kDa membrane binding protein, aids virus movement and induces the unfolded protein response (UPR) during PVX infection. TGBp3 was expressed from the Tobacco mosaic virus (TMV) genome (TMV-p3), and we noted the up-regulation of SKP1 and several endoplasmic reticulum (ER)-resident chaperones, including the ER luminal binding protein (BiP), protein disulphide isomerase (PDI), calreticulin (CRT) and calmodulin (CAM). Local lesions were seen on leaves inoculated with TMV-p3, but not TMV or PVX. Such lesions were the result of TGBp3-elicited programmed cell death (PCD), as shown by an increase in reactive oxygen species, DNA fragmentation and induction of SKP1 expression. UPR-related gene expression occurred within 8 h of TMV-p3 inoculation and declined before the onset of PCD. TGBp3-mediated cell death was suppressed in plants that overexpressed BiP, indicating that UPR induction by TGBp3 is a pro-survival mechanism. Anti-apoptotic genes Bcl-xl, CED-9 and Op-IAP were expressed in transgenic plants and suppressed N gene-mediated resistance to TMV, but failed to alleviate TGBp3-induced PCD. However, TGBp3-mediated cell death was reduced in SKP1-silenced Nicotiana benthamiana plants. The combined data suggest that TGBp3 triggers the UPR and elicits PCD in plants.
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Affiliation(s)
- Chang-Ming Ye
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
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15
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Ye CM, Chen S, Payton M, Dickman MB, Verchot J. TGBp3 triggers the unfolded protein response and SKP1-dependent programmed cell death. MOLECULAR PLANT PATHOLOGY 2013. [PMID: 23458484 DOI: 10.1111/mpp.12000 [epub ahead of print]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The Potato virus X (PVX) triple gene block protein 3 (TGBp3), an 8-kDa membrane binding protein, aids virus movement and induces the unfolded protein response (UPR) during PVX infection. TGBp3 was expressed from the Tobacco mosaic virus (TMV) genome (TMV-p3), and we noted the up-regulation of SKP1 and several endoplasmic reticulum (ER)-resident chaperones, including the ER luminal binding protein (BiP), protein disulphide isomerase (PDI), calreticulin (CRT) and calmodulin (CAM). Local lesions were seen on leaves inoculated with TMV-p3, but not TMV or PVX. Such lesions were the result of TGBp3-elicited programmed cell death (PCD), as shown by an increase in reactive oxygen species, DNA fragmentation and induction of SKP1 expression. UPR-related gene expression occurred within 8 h of TMV-p3 inoculation and declined before the onset of PCD. TGBp3-mediated cell death was suppressed in plants that overexpressed BiP, indicating that UPR induction by TGBp3 is a pro-survival mechanism. Anti-apoptotic genes Bcl-xl, CED-9 and Op-IAP were expressed in transgenic plants and suppressed N gene-mediated resistance to TMV, but failed to alleviate TGBp3-induced PCD. However, TGBp3-mediated cell death was reduced in SKP1-silenced Nicotiana benthamiana plants. The combined data suggest that TGBp3 triggers the UPR and elicits PCD in plants.
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Affiliation(s)
- Chang-Ming Ye
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
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16
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Nagano M, Takahara K, Fujimoto M, Tsutsumi N, Uchimiya H, Kawai-Yamada M. Arabidopsis sphingolipid fatty acid 2-hydroxylases (AtFAH1 and AtFAH2) are functionally differentiated in fatty acid 2-hydroxylation and stress responses. PLANT PHYSIOLOGY 2012; 159:1138-48. [PMID: 22635113 PMCID: PMC3387700 DOI: 10.1104/pp.112.199547] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 05/17/2012] [Indexed: 05/18/2023]
Abstract
2-Hydroxy fatty acids (2-HFAs) are predominantly present in sphingolipids and have important physicochemical and physiological functions in eukaryotic cells. Recent studies from our group demonstrated that sphingolipid fatty acid 2-hydroxylase (FAH) is required for the function of Arabidopsis (Arabidopsis thaliana) Bax inhibitor-1 (AtBI-1), which is an endoplasmic reticulum membrane-localized cell death suppressor. However, little is known about the function of two Arabidopsis FAH homologs (AtFAH1 and AtFAH2), and it remains unclear whether 2-HFAs participate in cell death regulation. In this study, we found that both AtFAH1 and AtFAH2 had FAH activity, and the interaction with Arabidopsis cytochrome b₅ was needed for the sufficient activity. 2-HFA analysis of AtFAH1 knockdown lines and atfah2 mutant showed that AtFAH1 mainly 2-hydroxylated very-long-chain fatty acid (VLCFA), whereas AtFAH2 selectively 2-hydroxylated palmitic acid in Arabidopsis. In addition, 2-HFAs were related to resistance to oxidative stress, and AtFAH1 or 2-hydroxy VLCFA showed particularly strong responses to oxidative stress. Furthermore, AtFAH1 interacted with AtBI-1 via cytochrome b₅ more preferentially than AtFAH2. Our results suggest that AtFAH1 and AtFAH2 are functionally different FAHs, and that AtFAH1 or 2-hydroxy VLCFA is a key factor in AtBI-1-mediated cell death suppression.
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Mittler R, Finka A, Goloubinoff P. How do plants feel the heat? Trends Biochem Sci 2012; 37:118-25. [DOI: 10.1016/j.tibs.2011.11.007] [Citation(s) in RCA: 534] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 11/08/2011] [Accepted: 11/21/2011] [Indexed: 10/14/2022]
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18
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Cebulski J, Malouin J, Pinches N, Cascio V, Austriaco N. Yeast Bax inhibitor, Bxi1p, is an ER-localized protein that links the unfolded protein response and programmed cell death in Saccharomyces cerevisiae. PLoS One 2011; 6:e20882. [PMID: 21673967 PMCID: PMC3108976 DOI: 10.1371/journal.pone.0020882] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 05/11/2011] [Indexed: 12/27/2022] Open
Abstract
Bax inhibitor-1 (BI-1) is an anti-apoptotic gene whose expression is upregulated in a wide range of human cancers. Studies in both mammalian and plant cells suggest that the BI-1 protein resides in the endoplasmic reticulum and is involved in the unfolded protein response (UPR) that is triggered by ER stress. It is thought to act via a mechanism involving altered calcium dynamics. In this paper, we provide evidence that the Saccharomyces cerevisiae protein encoded by the open reading frame, YNL305C, is a bona fide homolog for BI-1. First, we confirm that yeast cells from two different strain backgrounds lacking YNL305C, which we have renamed BXI1, are more sensitive to heat-shock induced cell death than wildtype controls even though they have indistinguishable growth rates at 30°C. They are also more susceptible both to ethanol-induced and to glucose-induced programmed cell death. Significantly, we show that Bxi1p-GFP colocalizes with the ER localized protein Sec63p-RFP. We have also discovered that Δbxi1 cells are not only more sensitive to drugs that induce ER stress, but also have a decreased unfolded protein response as measured with a UPRE-lacZ reporter. Finally, we have discovered that deleting BXI1 diminishes the calcium signaling response in response to the accumulation of unfolded proteins in the ER as measured by a calcineurin-dependent CDRE-lacZ reporter. In toto, our data suggests that the Bxi1p, like its metazoan homologs, is an ER-localized protein that links the unfolded protein response and programmed cell death.
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Affiliation(s)
- James Cebulski
- Department of Biology, Providence College, Providence, Rhode Island, United States of America
| | - Joshua Malouin
- Department of Biology, Providence College, Providence, Rhode Island, United States of America
| | - Nathan Pinches
- Department of Biology, Providence College, Providence, Rhode Island, United States of America
| | - Vincent Cascio
- Department of Biology, Providence College, Providence, Rhode Island, United States of America
| | - Nicanor Austriaco
- Department of Biology, Providence College, Providence, Rhode Island, United States of America
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Rong J, Chen L, Toth JI, Tcherpakov M, Petroski MD, Reed JC. Bifunctional apoptosis regulator (BAR), an endoplasmic reticulum (ER)-associated E3 ubiquitin ligase, modulates BI-1 protein stability and function in ER Stress. J Biol Chem 2011; 286:1453-63. [PMID: 21068390 PMCID: PMC3020754 DOI: 10.1074/jbc.m110.175232] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 10/18/2010] [Indexed: 01/03/2023] Open
Abstract
Accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes ER stress and activates inositol-requiring protein-1 (IRE1), among other ER-associated signaling proteins of the unfolded protein response (UPR) in mammalian cells. IRE1 signaling becomes attenuated under prolonged ER stress. The mechanisms by which this occurs are not well understood. An ER resident protein, Bax inhibitor-1 (BI-1), interacts with IRE1 and directly inhibits IRE1 activity. However, little is known about regulation of the BI-1 protein. We show here that bifunctional apoptosis regulator (BAR) functions as an ER-associated RING-type E3 ligase, interacts with BI-1, and promotes proteasomal degradation of BI-1. Overexpression of BAR reduced BI-1 protein levels in a RING-dependent manner. Conversely, knockdown of endogenous BAR increased BI-1 protein levels and enhanced inhibition of IRE1 signaling during ER stress. We also found that the levels of endogenous BAR were reduced under prolonged ER stress. Our findings suggest that post-translational regulation of the BI-1 protein by E3 ligase BAR contributes to the dynamic control of IRE1 signaling during ER stress.
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Affiliation(s)
- Juan Rong
- From the Sanford-Burnham Medical Research Institute, Program on Apoptosis and Cell Death Research, La Jolla, California 92037
| | - Lili Chen
- From the Sanford-Burnham Medical Research Institute, Program on Apoptosis and Cell Death Research, La Jolla, California 92037
| | - Julia I. Toth
- From the Sanford-Burnham Medical Research Institute, Program on Apoptosis and Cell Death Research, La Jolla, California 92037
| | - Marianna Tcherpakov
- From the Sanford-Burnham Medical Research Institute, Program on Apoptosis and Cell Death Research, La Jolla, California 92037
| | - Matthew D. Petroski
- From the Sanford-Burnham Medical Research Institute, Program on Apoptosis and Cell Death Research, La Jolla, California 92037
| | - John C. Reed
- From the Sanford-Burnham Medical Research Institute, Program on Apoptosis and Cell Death Research, La Jolla, California 92037
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