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Liu F, Qu PY, Li JP, Yang LN, Geng YJ, Lu JY, Zhang Y, Li S. Arabidopsis protein S-acyl transferases positively mediate BR signaling through S-acylation of BSK1. Proc Natl Acad Sci U S A 2024; 121:e2322375121. [PMID: 38315835 PMCID: PMC10873554 DOI: 10.1073/pnas.2322375121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 01/05/2024] [Indexed: 02/07/2024] Open
Abstract
Protein S-acyl transferases (PATs) catalyze S-acylation, a reversible post-translational modification critical for membrane association, trafficking, and stability of substrate proteins. Many plant proteins are potentially S-acylated but few have corresponding PATs identified. By using genomic editing, confocal imaging, pharmacological, genetic, and biochemical assays, we demonstrate that three Arabidopsis class C PATs positively regulate BR signaling through S-acylation of BRASSINOSTEROID-SIGNALING KINASE1 (BSK1). PAT19, PAT20, and PAT22 associate with the plasma membrane (PM) and the trans-Golgi network/early endosome (TGN/EE). Functional loss of all three genes results in a plethora of defects, indicative of reduced BR signaling and rescued by enhanced BR signaling. PAT19, PAT20, and PAT22 interact with BSK1 and are critical for the S-acylation of BSK1, and for BR signaling. The PM abundance of BSK1 was reduced by functional loss of PAT19, PAT20, and PAT22 whereas abolished by its S-acylation-deficient point mutations, suggesting a key role of S-acylation in its PM targeting. Finally, an active BR analog induces vacuolar trafficking and degradation of PAT19, PAT20, or PAT22, suggesting that the S-acylation of BSK1 by the three PATs serves as a negative feedback module in BR signaling.
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Affiliation(s)
- Fei Liu
- Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin300071, China
| | - Peng-Yu Qu
- Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin300071, China
| | - Ji-Peng Li
- College of Life Sciences, Shandong Agricultural University, Tai’an271018, China
| | - Li-Na Yang
- College of Life Sciences, Shandong Agricultural University, Tai’an271018, China
| | - Yuan-Jun Geng
- College of Life Sciences, Shandong Agricultural University, Tai’an271018, China
| | - Jin-Yu Lu
- Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin300071, China
| | - Yan Zhang
- Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin300071, China
| | - Sha Li
- College of Life Sciences, Shandong Agricultural University, Tai’an271018, China
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2
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Wan W, Zhang S, Zhao M, OuYang X, Yu Y, Xiong X, Zhao N, Jiao J. Lysosomal trafficking regulator restricts intracellular growth of Coxiella burnetii by inhibiting the expansion of Coxiella-containing vacuole and upregulating nos2 expression. Front Cell Infect Microbiol 2024; 13:1336600. [PMID: 38282619 PMCID: PMC10812120 DOI: 10.3389/fcimb.2023.1336600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 12/26/2023] [Indexed: 01/30/2024] Open
Abstract
Coxiella burnetii is an obligate intracellular bacterium that causes Q fever, a zoonotic disease typically manifests as a severe flu-illness. After invading into the host cells, C. burnetii delivers effectors to regulate the vesicle trafficking and fusion events to form a large and mature Coxiella-containing vacuole (CCV), providing sufficient space and nutrition for its intracellular growth and proliferation. Lysosomal trafficking regulator (LYST) is a member of the Beige and Chediak-Higashi syndrome (BEACH) family, which regulates the transport of vesicles to lysosomes and regulates TLR signaling pathway, but the effect of LYST on C. burnetii infection is unclear. In this study, a series of experiments has been conducted to investigate the influence of LYST on intracellular growth of C. burnetii. Our results showed that lyst transcription was up-regulated in the host cells after C. burnetii infection, but there is no significant change in lyst expression level after infection with the Dot/Icm type IV secretion system (T4SS) mutant strain, while CCVs expansion and significantly increasing load of C. burnetii appeared in the host cells with a silenced lyst gene, suggesting LYST inhibits the intracellular proliferation of C. burnetii by reducing CCVs size. Then, the size of CCVs and the load of C. burnetii in the HeLa cells pretreated with E-64d were significantly decreased. In addition, the level of iNOS was decreased significantly in LYST knockout THP-1 cells, which was conducive to the intracellular replication of C. burnetii. This data is consistent with the phenotype of L-NMMA-treated THP-1 cells infected with C. burnetii. Our results revealed that the upregulation of lyst transcription after infection is due to effector secretion of C. burnetii and LYST inhibit the intracellular replication of C. burnetii by reducing the size of CCVs and inducing nos2 expression.
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Affiliation(s)
- Weiqiang Wan
- College of Life Sciences, Southwest Forestry University, Kunming, China
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Shan Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Mingliang Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Xuan OuYang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yonghui Yu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Xiaolu Xiong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Ning Zhao
- College of Life Sciences, Southwest Forestry University, Kunming, China
| | - Jun Jiao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
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3
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Liu M, Wang C, Ji Z, Lu J, Zhang L, Li C, Huang J, Yang G, Yan K, Zhang S, Zheng C, Wu C. Regulation of drought tolerance in Arabidopsis involves the PLATZ4-mediated transcriptional repression of plasma membrane aquaporin PIP2;8. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023. [PMID: 37025007 DOI: 10.1111/tpj.16235] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 06/19/2023]
Abstract
Plant A/T-rich protein and zinc-binding protein (PLATZ) transcription factors play important roles in plant growth, development and abiotic stress responses. However, how PLATZ influences plant drought tolerance remains poorly understood. The present study showed that PLATZ4 increased drought tolerance in Arabidopsis thaliana by causing stomatal closure. Transcriptional profiling analysis revealed that PLATZ4 affected the expression of a set of genes involved in water and ion transport, antioxidant metabolism, small peptides and abscisic acid (ABA) signaling. Among these genes, the direct binding of PLATZ4 to the A/T-rich sequences in the plasma membrane intrinsic protein 2;8 (PIP2;8) promoter was identified. PIP2;8 consistently reduced drought tolerance in Arabidopsis through inhibiting stomatal closure. PIP2;8 was localized in the plasma membrane, exhibited water channel activity in Xenopus laevis oocytes and acted epistatically to PLATZ4 in regulating the drought stress response in Arabidopsis. PLATZ4 increased ABA sensitivity through upregulating the expression of ABSCISIC ACID INSENSITIVE 3 (ABI3), ABI4 and ABI5. The transcripts of PLATZ4 were induced to high levels in vegetative seedlings under drought and ABA treatments within 6 and 3 h, respectively. Collectively, these findings reveal that PLATZ4 positively influences plant drought tolerance through regulating the expression of PIP2;8 and genes involved in ABA signaling.
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Affiliation(s)
- Miao Liu
- State Key Laboratory of Crop Biology, Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-Alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Chunyan Wang
- State Key Laboratory of Crop Biology, Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-Alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Zhen Ji
- State Key Laboratory of Crop Biology, Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-Alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Junyao Lu
- State Key Laboratory of Crop Biology, Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-Alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Lei Zhang
- State Key Laboratory of Crop Biology, Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-Alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Chunlong Li
- Hubei Hongshan Laboratory, Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jinguang Huang
- State Key Laboratory of Crop Biology, Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-Alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Guodong Yang
- State Key Laboratory of Crop Biology, Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-Alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Kang Yan
- State Key Laboratory of Crop Biology, Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-Alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Shizhong Zhang
- State Key Laboratory of Crop Biology, Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-Alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Chengchao Zheng
- State Key Laboratory of Crop Biology, Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-Alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Changai Wu
- State Key Laboratory of Crop Biology, Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-Alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
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4
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Sieńko K, Poormassalehgoo A, Yamada K, Goto-Yamada S. Microautophagy in Plants: Consideration of Its Molecular Mechanism. Cells 2020; 9:cells9040887. [PMID: 32260410 PMCID: PMC7226842 DOI: 10.3390/cells9040887] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 02/06/2023] Open
Abstract
Microautophagy is a type of autophagy. It is characterized by direct enclosing with the vacuolar/lysosomal membrane, which completes the isolation and uptake of cell components in the vacuole. Several publications present evidence that plants exhibit microautophagy. Plant microautophagy is involved in anthocyanin accumulation in the vacuole, eliminating damaged chloroplasts and degrading cellular components during starvation. However, information on the molecular mechanism of microautophagy is less available than that on the general macroautophagy, because the research focusing on microautophagy has not been widely reported. In yeast and animals, it is suggested that microautophagy can be classified into several types depending on morphology and the requirements of autophagy-related (ATG) genes. This review summarizes the studies on plant microautophagy and discusses possible techniques for a future study in this field while taking into account the information on microautophagy obtained from yeast and animals.
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5
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Yamada K, Goto-Yamada S, Nakazaki A, Kunieda T, Kuwata K, Nagano AJ, Nishimura M, Hara-Nishimura I. Endoplasmic reticulum-derived bodies enable a single-cell chemical defense in Brassicaceae plants. Commun Biol 2020; 3:21. [PMID: 31937912 PMCID: PMC6959254 DOI: 10.1038/s42003-019-0739-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/10/2019] [Indexed: 01/23/2023] Open
Abstract
Brassicaceae plants have a dual-cell type of chemical defense against herbivory. Here, we show a novel single-cell defense involving endoplasmic reticulum (ER)-derived organelles (ER bodies) and the vacuoles. We identify various glucosinolates as endogenous substrates of the ER-body β-glucosidases BGLU23 and BGLU21. Woodlice strongly prefer to eat seedlings of bglu23 bglu21 or a glucosinolate-deficient mutant over wild-type seedlings, confirming that the β-glucosidases have a role in chemical defense: production of toxic compounds upon organellar damage. Deficiency of the Brassicaceae-specific protein NAI2 prevents ER-body formation, which results in a loss of BGLU23 and a loss of resistance to woodlice. Hence, NAI2 that interacts with BGLU23 is essential for sequestering BGLU23 in ER bodies and preventing its degradation. Artificial expression of NAI2 and BGLU23 in non-Brassicaceae plants results in the formation of ER bodies, indicating that acquisition of NAI2 by Brassicaceae plants is a key step in developing their single-cell defense system. Kenji Yamada et al. describe a single-cell chemical defense strategy in Brassicaceae plants that requires formation of endoplasmic reticulum-derived organelles for the accumulation of β-glucosidases. They find that seedlings lacking a specific β-glucosidase lose their resistance to predation by woodlice.
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Affiliation(s)
- Kenji Yamada
- Malopolska Centre of Biotechnology, Jagiellonian University, 30-387, Krakow, Poland. .,Department of Cell Biology, National Institute for Basic Biology, Okazaki, 444-8585, Japan. .,Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan.
| | - Shino Goto-Yamada
- Malopolska Centre of Biotechnology, Jagiellonian University, 30-387, Krakow, Poland.,Department of Cell Biology, National Institute for Basic Biology, Okazaki, 444-8585, Japan.,Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Akiko Nakazaki
- Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Tadashi Kunieda
- Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan.,Faculty of Science and Engineering, Konan University, Kobe, 658-8501, Japan.,Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, 630-0192, Japan
| | - Keiko Kuwata
- Institute of Transformative Bio-Molecules, Nagoya University, Nagoya, 464-8601, Japan
| | - Atsushi J Nagano
- Faculty of Agriculture, Ryukoku University, Otsu, Shiga, 520-2194, Japan
| | - Mikio Nishimura
- Department of Cell Biology, National Institute for Basic Biology, Okazaki, 444-8585, Japan. .,Faculty of Science and Engineering, Konan University, Kobe, 658-8501, Japan.
| | - Ikuko Hara-Nishimura
- Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan. .,Faculty of Science and Engineering, Konan University, Kobe, 658-8501, Japan.
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6
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Goto-Yamada S, Oikawa K, Bizan J, Shigenobu S, Yamaguchi K, Mano S, Hayashi M, Ueda H, Hara-Nishimura I, Nishimura M, Yamada K. Sucrose Starvation Induces Microautophagy in Plant Root Cells. FRONTIERS IN PLANT SCIENCE 2019; 10:1604. [PMID: 31850051 PMCID: PMC6901504 DOI: 10.3389/fpls.2019.01604] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 11/14/2019] [Indexed: 05/26/2023]
Abstract
Autophagy is an essential system for degrading and recycling cellular components for survival during starvation conditions. Under sucrose starvation, application of a papain protease inhibitor E-64d to the Arabidopsis root and tobacco BY-2 cells induced the accumulation of vesicles, labeled with a fluorescent membrane marker FM4-64. The E-64d-induced vesicle accumulation was reduced in the mutant defective in autophagy-related genes ATG2, ATG5, and ATG7, suggesting autophagy is involved in the formation of these vesicles. To clarify the formation of these vesicles in detail, we monitored time-dependent changes of tonoplast, and vesicle accumulation in sucrose-starved cells. We found that these vesicles were derived from the tonoplast and produced by microautophagic process. The tonoplast proteins were excluded from the vesicles, suggesting that the vesicles are generated from specific membrane domains. Concanamycin A treatment in GFP-ATG8a transgenic plants showed that not all FM4-64-labeled vesicles, which were derived from the tonoplast, contained the ATG8a-containing structure. These results suggest that ATG8a may not always be necessary for microautophagy.
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Affiliation(s)
- Shino Goto-Yamada
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Kazusato Oikawa
- Department of Cell Biology, National Institute for Basic Biology, Okazaki, Japan
| | - Jakub Bizan
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Shuji Shigenobu
- NIBB Core Research Facilities, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
| | - Katsushi Yamaguchi
- NIBB Core Research Facilities, National Institute for Basic Biology, Okazaki, Japan
| | - Shoji Mano
- Department of Cell Biology, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
| | - Makoto Hayashi
- Department of Bioscience, Nagahama Institute of Bioscience and Technology, Nagahama, Japan
| | - Haruko Ueda
- Faculty of Science and Engineering, Konan University, Kobe, Japan
| | | | - Mikio Nishimura
- Faculty of Science and Engineering, Konan University, Kobe, Japan
| | - Kenji Yamada
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
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7
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QUIRKY regulates root epidermal cell patterning through stabilizing SCRAMBLED to control CAPRICE movement in Arabidopsis. Nat Commun 2019; 10:1744. [PMID: 30988311 PMCID: PMC6465271 DOI: 10.1038/s41467-019-09715-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 03/26/2019] [Indexed: 12/04/2022] Open
Abstract
SCM, a leucine-rich repeat receptor-like kinase, is required for root epidermal cells to appropriately interpret their location and generate the proper cell-type pattern during Arabidopsis root development. Here, via a screen for scm-like mutants we describe a new allele of the QKY gene. We find that QKY is required for the appropriate spatial expression of several epidermal cell fate regulators in a similar manner as SCM in roots, and that QKY and SCM are necessary for the efficient movement of CPC between epidermal cells. We also show that turnover of SCM is mediated by a vacuolar degradation pathway triggered by ubiquitination, and that QKY prevents this SCM ubiquitination through their physical interaction. These results suggest that QKY stabilizes SCM through interaction, and this complex facilitates CPC movement between the epidermal cells to help establish the cell-type pattern in the Arabidopsis root epidermis. SCM is a receptor-like kinase that ensures proper root patterning. Here, Song et al. find that SCM promotes the movement of CPC from non-hair cells to neighboring root epidermal cells and identify QKY as an additional facilitator of CPC mobility that acts by preventing vacuolar degradation of SCM.
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8
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Palocci C, Valletta A, Chronopoulou L, Donati L, Bramosanti M, Brasili E, Baldan B, Pasqua G. Endocytic pathways involved in PLGA nanoparticle uptake by grapevine cells and role of cell wall and membrane in size selection. PLANT CELL REPORTS 2017; 36:1917-1928. [PMID: 28913707 DOI: 10.1007/s00299-017-2206-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 09/05/2017] [Indexed: 05/28/2023]
Abstract
PLGA NPs' cell uptake involves different endocytic pathways. Clathrin-independent endocytosis is the main internalization route. The cell wall plays a more prominent role than the plasma membrane in NPs' size selection. In the last years, many studies on absorption and cell uptake of nanoparticles by plants have been conducted, but the understanding of the internalization mechanisms is still largely unknown. In this study, polydispersed and monodispersed poly(lactic-co-glycolic) acid nanoparticles (PLGA NPs) were synthesized, and a strategy combining the use of transmission electron microscopy (TEM), confocal analysis, fluorescently labeled PLGA NPs, a probe for endocytic vesicles (FM4-64), and endocytosis inhibitors (i.e., wortmannin, ikarugamycin, and salicylic acid) was employed to shed light on PLGA NP cell uptake in grapevine cultured cells and to assess the role of the cell wall and plasma membrane in size selection of PLGA NPs. The ability of PLGA NPs to cross the cell wall and membrane was confirmed by TEM and fluorescence microscopy. A strong adhesion of PLGA NPs to the outer side of the cell wall was observed, presumably due to electrostatic interactions. Confocal microscopy and treatment with endocytosis inhibitors suggested the involvement of both clathrin-dependent and clathrin-independent endocytosis in cell uptake of PLGA NPs and the latter appeared to be the main internalization pathway. Experiments on grapevine protoplasts revealed that the cell wall plays a more prominent role than the plasma membrane in size selection of PLGA NPs. While the cell wall prevents the uptake of PLGA NPs with diameters over 50 nm, the plasma membrane can be crossed by PLGA NPs with a diameter of 500-600 nm.
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Affiliation(s)
- Cleofe Palocci
- Department of Chemistry, University of Rome La Sapienza, Piazzale A. Moro 5, 00185, Rome, Italy
| | - Alessio Valletta
- Department of Environmental Biology, University of Rome La Sapienza, Piazzale A. Moro 5, 00185, Rome, Italy.
| | - Laura Chronopoulou
- Department of Chemistry, University of Rome La Sapienza, Piazzale A. Moro 5, 00185, Rome, Italy
| | - Livia Donati
- Department of Environmental Biology, University of Rome La Sapienza, Piazzale A. Moro 5, 00185, Rome, Italy
| | - Marco Bramosanti
- Department of Chemistry, University of Rome La Sapienza, Piazzale A. Moro 5, 00185, Rome, Italy
| | - Elisa Brasili
- Department of Chemistry, University of Rome La Sapienza, Piazzale A. Moro 5, 00185, Rome, Italy
| | - Barbara Baldan
- Department of Biology, University of Padua, Via Ugo Bassi 58/B, 35131, Padua, Italy
| | - Gabriella Pasqua
- Department of Environmental Biology, University of Rome La Sapienza, Piazzale A. Moro 5, 00185, Rome, Italy
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9
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The relationship between vacuolation and initiation of PCD in rice (Oryza sativa) aleurone cells. Sci Rep 2017; 7:41245. [PMID: 28117452 PMCID: PMC5259747 DOI: 10.1038/srep41245] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 12/19/2016] [Indexed: 02/05/2023] Open
Abstract
Vacuole fusion is a necessary process for the establishment of a large central vacuole, which is the central location of various hydrolytic enzymes and other factors involved in death at the beginning of plant programmed cell death (PCD). In our report, the fusion of vacuoles has been presented in two ways: i) small vacuoles coalesce to form larger vacuoles through membrane fusion, and ii) larger vacuoles combine with small vacuoles when small vacuoles embed into larger vacuoles. Regardless of how fusion occurs, a large central vacuole is formed in rice (Oryza sativa) aleurone cells. Along with the development of vacuolation, the rupture of the large central vacuole leads to the loss of the intact plasma membrane and the degradation of the nucleus, resulting in cell death. Stabilizing or disrupting the structure of actin filaments (AFs) inhibits or promotes the fusion of vacuoles, which delays or induces PCD. In addition, the inhibitors of the vacuolar processing enzyme (VPE) and cathepsin B (CathB) block the occurrence of the large central vacuole and delay the progression of PCD in rice aleurone layers. Overall, our findings provide further evidence for the rupture of the large central vacuole triggering the PCD in aleruone layers.
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10
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Reguera M, Bassil E, Tajima H, Wimmer M, Chanoca A, Otegui MS, Paris N, Blumwald E. pH Regulation by NHX-Type Antiporters Is Required for Receptor-Mediated Protein Trafficking to the Vacuole in Arabidopsis. THE PLANT CELL 2015; 27:1200-17. [PMID: 25829439 PMCID: PMC4558692 DOI: 10.1105/tpc.114.135699] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/26/2015] [Accepted: 03/12/2015] [Indexed: 05/18/2023]
Abstract
Protein trafficking requires proper ion and pH homeostasis of the endomembrane system. The NHX-type Na(+)/H(+) antiporters NHX5 and NHX6 localize to the Golgi, trans-Golgi network, and prevacuolar compartments and are required for growth and trafficking to the vacuole. In the nhx5 nhx6 T-DNA insertional knockouts, the precursors of the 2S albumin and 12S globulin storage proteins accumulated and were missorted to the apoplast. Immunoelectron microscopy revealed the presence of vesicle clusters containing storage protein precursors and vacuolar sorting receptors (VSRs). Isolation and identification of complexes of VSRs with unprocessed 12S globulin by 2D blue-native PAGE/SDS-PAGE indicated that the nhx5 nhx6 knockouts showed compromised receptor-cargo association. In vivo interaction studies using bimolecular fluorescence complementation between VSR2;1, aleurain, and 12S globulin suggested that nhx5 nhx6 knockouts showed a significant reduction of VSR binding to both cargoes. In vivo pH measurements indicated that the lumens of VSR compartments containing aleurain, as well as the trans-Golgi network and prevacuolar compartments, were significantly more acidic in nhx5 nhx6 knockouts. This work demonstrates the importance of NHX5 and NHX6 in maintaining endomembrane luminal pH and supports the notion that proper vacuolar trafficking and proteolytic processing of storage proteins require endomembrane pH homeostasis.
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Affiliation(s)
- Maria Reguera
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Elias Bassil
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Hiromi Tajima
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Monika Wimmer
- Institute of Crop Science and Resource Conservation, Division of Plant Nutrition, University of Bonn, D-53115 Bonn, Germany
| | - Alexandra Chanoca
- Departments of Botany and Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Marisa S Otegui
- Departments of Botany and Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Nadine Paris
- Biochemistry and Plant Molecular Biology Laboratory, Unité Mixte de Recherche 5004, 34060 Montpellier, France
| | - Eduardo Blumwald
- Department of Plant Sciences, University of California, Davis, California 95616
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11
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Voitsekhovskaja OV, Schiermeyer A, Reumann S. Plant peroxisomes are degraded by starvation-induced and constitutive autophagy in tobacco BY-2 suspension-cultured cells. FRONTIERS IN PLANT SCIENCE 2014; 5:629. [PMID: 25477890 PMCID: PMC4235271 DOI: 10.3389/fpls.2014.00629] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 10/23/2014] [Indexed: 05/07/2023]
Abstract
Very recently, autophagy has been recognized as an important degradation pathway for quality control of peroxisomes in Arabidopsis plants. To further characterize the role of autophagy in plant peroxisome degradation, we generated stable transgenic suspension-cultured cell lines of heterotrophic Nicotiana tabacum L. cv. Bright Yellow 2 expressing a peroxisome-targeted version of enhanced yellow fluorescent protein. Indeed, this cell line model system proved advantageous for detailed cytological analyses of autophagy stages and for quantification of cellular peroxisome pools under different culturing conditions and upon inhibitor applications. Complementary biochemical, cytological, and pharmacological analyses provided convincing evidence for peroxisome degradation by bulk autophagy during carbohydrate starvation. This degradation was slowed down by the inhibitor of autophagy, 3-methyladenine (3-MA), but the 3-MA effect ceased at advanced stages of starvation, indicating that another degradation mechanism for peroxisomes might have taken over. 3-MA also caused an increase particularly in peroxisomal proteins and cellular peroxisome numbers when applied under nutrient-rich conditions in the logarithmic growth phase, suggesting a high turnover rate for peroxisomes by basal autophagy under non-stress conditions. Together, our data demonstrate that a great fraction of the peroxisome pool is subject to extensive autophagy-mediated turnover under both nutrient starvation and optimal growth conditions. Our analyses of the cellular pool size of peroxisomes provide a new tool for quantitative investigations of the role of plant peroxisomes in reactive oxygen species metabolism.
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Affiliation(s)
- Olga V. Voitsekhovskaja
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-Universität GöttingenGöttingen, Germany
- Komarov Botanical Institute, Russian Academy of Sciences, Laboratory of Plant Ecological PhysiologySaint Petersburg, Russia
| | - Andreas Schiermeyer
- Abteilung Pflanzenbiotechnologie, Fraunhofer-Institut für Molekularbiologie und Angewandte OekologieAachen, Germany
| | - Sigrun Reumann
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-Universität GöttingenGöttingen, Germany
- Institute for Mathematics and Natural Sciences, Faculty of Science and Technology, Centre for Organelle Research, University of StavangerStavanger, Norway
- Faculty of Mathematics, Informatics and Natural Sciences, Biocentre Klein Flottbek, University of HamburgHamburg, Germany
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12
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Merkulova EA, Guiboileau A, Naya L, Masclaux-Daubresse C, Yoshimoto K. Assessment and optimization of autophagy monitoring methods in Arabidopsis roots indicate direct fusion of autophagosomes with vacuoles. PLANT & CELL PHYSIOLOGY 2014; 55:715-26. [PMID: 24566535 DOI: 10.1093/pcp/pcu041] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Autophagy is a degradation pathway that recycles cell materials upon encountering stress conditions or during specific developmental processes. To better understand the physiological roles of autophagy, proper monitoring methods are very important. In mammals and yeast, monitoring of autophagy is often performed with a green fluorescent protein (GFP)-ATG8 fusion protein or with acidotropic dyes such as monodansylcadaverine (MDC) and LysoTracker Red (LTR). To evaluate these monitoring methods, here we examined these systems by inducing autophagy in Arabidopsis thaliana roots as a model for monitoring autophagy in planta. Under carbon- and nitrogen-starved conditions, the number and size of vesicles labeled by GFP-ATG8 was increased for several hours and then gradually decreased to a level higher than that observed before the start of the experiment. We also observed the disappearance of GFP-ATG8-labeled vesicles after treatment with wortmannin, a phosphatidylinositol 3-kinase inhibitor known as an autophagy inhibitor, showing that the GFP-ATG8 transgenic line constitutes an excellent method for monitoring autophagy. These data were compared with plants stained with MDC and LTR. There was no appreciable MDC/LTR staining of small organelles in the root under the induction of autophagy. Some vesicles were eventually observed in the root tip only, but co-localization experiments, as well as experiments with autophagy-deficient atg mutants, provided the evidence that these structures were located in the vacuole and were not manifestly autophagosomes and/or autolysosomes. Extreme caution should therefore be used when monitoring autophagy with the aid of MDC/LTR. Additionally, our observations strongly suggest that autophagosomes fuse directly to vacuoles in Arabidopsis roots.
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13
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Takagi J, Renna L, Takahashi H, Koumoto Y, Tamura K, Stefano G, Fukao Y, Kondo M, Nishimura M, Shimada T, Brandizzi F, Hara-Nishimura I. MAIGO5 functions in protein export from Golgi-associated endoplasmic reticulum exit sites in Arabidopsis. THE PLANT CELL 2013; 25:4658-75. [PMID: 24280388 PMCID: PMC3875742 DOI: 10.1105/tpc.113.118158] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 10/08/2013] [Accepted: 10/22/2013] [Indexed: 05/19/2023]
Abstract
Plant cells face unique challenges to efficiently export cargo from the endoplasmic reticulum (ER) to mobile Golgi stacks. Coat protein complex II (COPII) components, which include two heterodimers of Secretory23/24 (Sec23/24) and Sec13/31, facilitate selective cargo export from the ER; however, little is known about the mechanisms that regulate their recruitment to the ER membrane, especially in plants. Here, we report a protein transport mutant of Arabidopsis thaliana, named maigo5 (mag5), which abnormally accumulates precursor forms of storage proteins in seeds. mag5-1 has a deletion in the putative ortholog of the Saccharomyces cerevisiae and Homo sapiens Sec16, which encodes a critical component of ER exit sites (ERESs). mag mutants developed abnormal structures (MAG bodies) within the ER and exhibited compromised ER export. A functional MAG5/SEC16A-green fluorescent protein fusion localized at Golgi-associated cup-shaped ERESs and cycled on and off these sites at a slower rate than the COPII coat. MAG5/SEC16A interacted with SEC13 and SEC31; however, in the absence of MAG5/SEC16A, recruitment of the COPII coat to ERESs was accelerated. Our results identify a key component of ER export in plants by demonstrating that MAG5/SEC16A is required for protein export at ERESs that are associated with mobile Golgi stacks, where it regulates COPII coat turnover.
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Affiliation(s)
- Junpei Takagi
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Luciana Renna
- Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Hideyuki Takahashi
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yasuko Koumoto
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kentaro Tamura
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Giovanni Stefano
- Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Yoichiro Fukao
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Maki Kondo
- Department of Cell Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Mikio Nishimura
- Department of Cell Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Tomoo Shimada
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Federica Brandizzi
- Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Ikuko Hara-Nishimura
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
- Address correspondence to
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14
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Kunieda T, Shimada T, Kondo M, Nishimura M, Nishitani K, Hara-Nishimura I. Spatiotemporal secretion of PEROXIDASE36 is required for seed coat mucilage extrusion in Arabidopsis. THE PLANT CELL 2013; 25:1355-67. [PMID: 23572548 PMCID: PMC3663273 DOI: 10.1105/tpc.113.110072] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/13/2013] [Accepted: 03/21/2013] [Indexed: 05/21/2023]
Abstract
The epidermal cells of the Arabidopsis thaliana seed coat, which correspond to the second layer of the outer integument (oi2), contain large quantities of a pectic polysaccharide called mucilage within the apoplastic space beneath the outer periclinal cell wall. Immediately after seed imbibition, the mucilage is extruded and completely envelops the seed in a gel-like capsule. We found that a class III peroxidase family protein, PEROXIDASE36 (PER36), functions as a mucilage extrusion factor. Expression of PER36 occurred only in oi2 cells for a few days around the torpedo stage. A PER36-green fluorescent protein fusion was secreted into the outer cell wall in a polarized manner. per36 mutants were defective in mucilage extrusion after seed imbibition due to the failure of outer cell wall rupture, although the mutants exhibited normal monosaccharide composition of the mucilage. This abnormal phenotype of per36 was rescued by pectin solubilization, which promoted cell wall loosening. These results suggest that PER36 regulates the degradation of the outer cell wall. Taken together, this work indicates that polarized secretion of PER36 in a developmental stage-dependent manner plays a role in cell wall modification of oi2 cells.
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Affiliation(s)
- Tadashi Kunieda
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Tomoo Shimada
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Maki Kondo
- Department of Cell Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Mikio Nishimura
- Department of Cell Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Kazuhiko Nishitani
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Ikuko Hara-Nishimura
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
- Address correspondence to
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15
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van der Hoorn RAL, Kaiser M. Probes for activity-based profiling of plant proteases. PHYSIOLOGIA PLANTARUM 2012; 145:18-27. [PMID: 21985675 DOI: 10.1111/j.1399-3054.2011.01528.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Proteases are key players in plant development and immunity. When and where these proteases act during these processes is difficult to predict from proteomic or transcriptomic data because proteases are tightly regulated by post-translational mechanisms such as processing, phosphorylation and the presence of cofactors or inhibitors. Protease activities can be displayed using activity-based probes that react with the catalytic site of proteases in a mechanism-dependent manner. Plant proteomes have been labeled with probes for caspases, vacuolar processing enzymes, papain-like cysteine proteases, the proteasome, subtilases, prolyloligopeptidases, serine carboxypeptidases and matrix metalloproteases. Here, we review these protease probes with a focus on the specificity determinants that reside in the probe and the detection methods dictated by the reporter tag.
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Affiliation(s)
- Renier A L van der Hoorn
- Plant Chemetics lab, Chemical Genomics Centre of the Max Planck Society, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
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16
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Ito E, Fujimoto M, Ebine K, Uemura T, Ueda T, Nakano A. Dynamic behavior of clathrin in Arabidopsis thaliana unveiled by live imaging. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 69:204-16. [PMID: 21910772 DOI: 10.1111/j.1365-313x.2011.04782.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Clathrin-coated vesicles (CCV) are necessary for selective transport events, including receptor-mediated endocytosis on the plasma membrane and cargo molecule sorting in the trans-Golgi network (TGN). Components involved in CCV formation include clathrin heavy and light chains and several adaptor proteins that are conserved among plants. Clathrin-dependent endocytosis has been shown to play an integral part in plant endocytosis. However, little information is known about clathrin dynamics in living plant cells. In this study, we have visualized clathrin in Arabidopsis thaliana by tagging clathrin light chain with green fluorescent protein (CLC-GFP). Quantitative evaluations of colocalization demonstrate that the majority of CLC-GFP is localized to the TGN, and a minor population is associated with multivesicular endosomes and the Golgi trans-cisternae. Live imaging further demonstrated the presence of highly dynamic clathrin-positive tubules and vesicles, which appeared to mediate interactions between the TGNs. CLC-GFP is also targeted to cell plates and the plasma membrane. Although CLC-GFP colocalizes with a dynamin isoform at the plasma membrane, these proteins exhibit distinct distributions at newly forming cell plates. This finding indicates independent functions of CLC (clathrin light chains) and dynamin during the formation of cell plates. We have also found that brefeldin A and wortmannin treatment causes distinctly different alterations in the dynamics and distribution of clathrin-coated domains at the plasma membrane. This could account for the different effects of these drugs on plant endocytosis.
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Affiliation(s)
- Emi Ito
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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17
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Oh-ye Y, Inoue Y, Moriyasu Y. Detecting autophagy in Arabidopsis roots by membrane-permeable cysteine protease inhibitor E-64d and endocytosis tracer FM4-64. PLANT SIGNALING & BEHAVIOR 2011; 6:1946-9. [PMID: 22105025 PMCID: PMC3337184 DOI: 10.4161/psb.6.12.18297] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Autophagy is the process by which cells degrade their own components in lysosomes or vacuoles. Autophagy in tobacco BY-2 cells cultured in sucrose-free medium takes place in formed, autolysosomes in the presence of a cysteine protease inhibitor. The autolysosomes in BY-2 cells are located in the endocytotic pathway and thus can be stained with fluorescent endocytosis marker FM4-64. In the present study, in order to detect autophagy in the root cells of Arabidopsis, we incubated root tips from Arabidopsis seedlings in culture medium containing the membrane-permeable cysteine protease inhibitor E-64d and FM4-64, and examined whether autolysosomes stained with FM4-64 are accumulated. The results suggest that autophagy accompanying the formation of autolysosomes also occurs in Arabidopsis root cells. Such autophagy appeared to occur constitutively in the root cells in nutrient-sufficient culture medium. Even in atg5 mutants in which an autophagy-related gene is disrupted, accumulation of the structures stained with FM4-64, which likely correspond to autolysosomes, was seen although at lower level than in wild type roots.
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Affiliation(s)
- Yuumi Oh-ye
- Graduate School of Science and Engineering; Saitama University; Saitama Japan
| | - Yuko Inoue
- Graduate School of Food and Nutritional Sciences; University of Shizuoka; Shizuoka, Japan
| | - Yuji Moriyasu
- Graduate School of Science and Engineering; Saitama University; Saitama Japan
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18
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Takatsuka C, Inoue Y, Higuchi T, Hillmer S, Robinson DG, Moriyasu Y. Autophagy in tobacco BY-2 cells cultured under sucrose starvation conditions: isolation of the autolysosome and its characterization. PLANT & CELL PHYSIOLOGY 2011; 52:2074-87. [PMID: 22039105 DOI: 10.1093/pcp/pcr137] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Tobacco culture cells carry out a large-scale degradation of intracellular proteins in order to survive under sucrose starvation conditions. We have previously suggested that this bulk degradation of cellular proteins is performed by autophagy, where autolysosomes formed de novo act as the major lytic compartments. The digestion process in autolysosomes can be retarded by addition of the cysteine protease inhibitor E-64c to the culture medium, resulting in the accumulation of autolysosomes. In the present study, we have investigated several properties of autolysosomes in tobacco cells. Electron microscopy showed that the autolysosomes contain osmiophilic particles, some of which resemble partially degraded mitochondria. It also revealed the presence of two kinds of autolysosome precursor structures; one resembled the isolation membrane and the other the autophagosome of mammalian cells. Immunofluorescence microscopy showed that autolysosomes contain acid phosphatase, in accordance with cytochemical enzyme analyses by light and electron microscopy in a previous study. Autolysosomes isolated by cell fractionation on Percoll gradients showed the localization of acid phosphatase, vacuolar H(+)-ATPase and cysteine protease. These results show that starvation-induced autophagy in tobacco cells follows a macroautophagic-type response similar to that described for other eukaryotes. However, our results indicate that, although the plant vacuole is often described as being equivalent to the lysosome of the animal cell, a new low pH lytic compartment-the autolysosome-also contributes to proteolytic degradation when tobacco cells are subjected to sucrose deprivation.
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Affiliation(s)
- Chihiro Takatsuka
- Graduate School of Science and Engineering, Saitama University, Saitama, Japan
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19
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Silva AT, Nguyen A, Ye C, Verchot J, Moon JH. Conjugated polymer nanoparticles for effective siRNA delivery to tobacco BY-2 protoplasts. BMC PLANT BIOLOGY 2010; 10:291. [PMID: 21192827 PMCID: PMC3023792 DOI: 10.1186/1471-2229-10-291] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 12/30/2010] [Indexed: 05/02/2023]
Abstract
BACKGROUND Post transcriptional gene silencing (PTGS) is a mechanism harnessed by plant biologists to knock down gene expression. siRNAs contribute to PTGS that are synthesized from mRNAs or viral RNAs and function to guide cellular endoribonucleases to target mRNAs for degradation. Plant biologists have employed electroporation to deliver artificial siRNAs to plant protoplasts to study gene expression mechanisms at the single cell level. One drawback of electroporation is the extensive loss of viable protoplasts that occurs as a result of the transfection technology. RESULTS We employed fluorescent conjugated polymer nanoparticles (CPNs) to deliver siRNAs and knockdown a target gene in plant protoplasts. CPNs are non toxic to protoplasts, having little impact on viability over a 72 h period. Microscopy and flow cytometry reveal that CPNs can penetrate protoplasts within 2 h of delivery. Cellular uptake of CPNs/siRNA complexes were easily monitored using epifluorescence microscopy. We also demonstrate that CPNs can deliver siRNAs targeting specific genes in the cellulose biosynthesis pathway (NtCesA-1a and NtCesA-1b). CONCLUSIONS While prior work showed that NtCesA-1 is a factor involved in cell wall synthesis in whole plants, we demonstrate that the same gene plays an essential role in cell wall regeneration in isolated protoplasts. Cell wall biosynthesis is central to cell elongation, plant growth and development. The experiments presented here shows that NtCesA is also a factor in cell viability. We show that CPNs are valuable vehicles for delivering siRNAs to plant protoplasts to study vital cellular pathways at the single cell level.
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Affiliation(s)
- Asitha T Silva
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, USA 74078
| | - Alien Nguyen
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Changming Ye
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, USA 74078
| | - Jeanmarie Verchot
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, USA 74078
| | - Joong Ho Moon
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
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20
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Kołodziejek I, van der Hoorn RAL. Mining the active proteome in plant science and biotechnology. Curr Opin Biotechnol 2010; 21:225-33. [DOI: 10.1016/j.copbio.2010.02.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Revised: 02/02/2010] [Accepted: 02/02/2010] [Indexed: 12/29/2022]
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21
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Aquea F, Johnston AJ, Cañon P, Grossniklaus U, Arce-Johnson P. TRAUCO, a Trithorax-group gene homologue, is required for early embryogenesis in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:1215-24. [PMID: 20118203 PMCID: PMC2826662 DOI: 10.1093/jxb/erp396] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 12/16/2009] [Accepted: 12/21/2009] [Indexed: 05/18/2023]
Abstract
Embryogenesis is a critical stage during the plant life cycle in which a unicellular zygote develops into a multicellular organism. Co-ordinated gene expression is thus necessary for proper embryo development. Polycomb and Trithorax group genes are members of evolutionarily conserved machinery that maintains the correct expression patterns of key developmental regulators by repressing and activating gene transcription. TRAUCO (TRO), a gene homologous to the Trithorax group of genes that can functionally complement a BRE2P yeast mutant, has been identified in Arabidopsis thaliana. It is demonstrated that TRO is a nuclear gene product expressed during embryogenesis, and loss of TRO function leads to impaired early embryo development. Embryos that arrested at the globular stage in the tro-1 mutant allele were fully rescued by a TRO expression clone, a demonstration that the tro-1 mutation is a true loss-of-function in TRO. Our data have established that TRO is the first trithorax-group gene homologue in plants that is required for early embryogenesis.
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Affiliation(s)
- Felipe Aquea
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, PO Box 114-D, Santiago, Chile
| | - Amal J. Johnston
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Department of Molecular Genetics. Corrensstrasse 3, D-06466 Gatersleben, Germany
- Institute of Plant Biology and Zürich-Basel Plant Science Center, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
| | - Paola Cañon
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, PO Box 114-D, Santiago, Chile
| | - Ueli Grossniklaus
- Institute of Plant Biology and Zürich-Basel Plant Science Center, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
| | - Patricio Arce-Johnson
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, PO Box 114-D, Santiago, Chile
- To whom correspondence should be addressed: E-mail:
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Abstract
Secretory and endocytic traffic through the post-Golgi endomembrane system regulates the abundance of plasma-membrane proteins such as receptors, transporters and ion channels, modulating the ability of a cell to communicate with its neighbours and to adapt to a changing environment. The major post-Golgi compartments are numerous and appear to be similar to their counterparts in animals. However, endosomes are rather ill defined morphologically but seem to be involved in specific trafficking pathways. Many plasma-membrane proteins cycle constitutively via endosomal compartments. The trans-Golgi network (TGN) appears to be an early endosome where secretory and endocytic traffic meet. Endocytosed proteins that are to be degraded are targeted to the vacuole via the multivesiculate prevacuolar compartment (PVC) whereas cycling proteins pass through recycling endosomes. The trafficking machinery involves the same classes of proteins as in other eukaryotes. However, there are modifications that match the specifics of post-Golgi traffic in plants. Although plants lack epithelia, some plasma-membrane proteins are located on specific faces of the cell which reflects polarized traffic and influences the physiological performance of the tissue. Plants also differentiate highly polarized tip-growing cells in which post-Golgi traffic is adapted to very high rates of targeted exocytosis, endocytosis and recycling.
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Affiliation(s)
- Sandra Richter
- ZMBP, Entwicklungsgenetik,Universität Tübingen, Auf der Morgenstelle 3, D-72076 Tübingen, Germany
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23
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Phan NQ, Kim SJ, Bassham DC. Overexpression of Arabidopsis sorting nexin AtSNX2b inhibits endocytic trafficking to the vacuole. MOLECULAR PLANT 2008; 1:961-976. [PMID: 19825596 DOI: 10.1093/mp/ssn057] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Sorting nexins are conserved proteins that function in vesicular trafficking and contain a characteristic phox homology (PX) domain. Here, we characterize the ubiquitously expressed Arabidopsis thaliana sorting nexin AtSNX2b. Sub-cellular fractionation studies indicate that AtSNX2b is peripherally associated with membranes. The AtSNX2b PX domain binds to phosphatidylinositol 3-phosphate in vitro and this association is required for the localization of GFP-AtSNX2b to punctate structures in vivo, identified as the trans-Golgi network, prevacuolar compartment and endosomes. Overexpression of GFP-tagged AtSNX2b produces enlarged GFP-labeled compartments that can also be labeled by the endocytic tracer FM4-64. Endocytic trafficking of FM4-64 to the vacuole is arrested in these GFP-AtSNX2b compartments, and similar FM4-64-accumulating compartments are seen upon overexpression of untagged AtSNX2b. This suggests that exit of membrane components from these enlarged or aggregated endosomes is inhibited. Vacuolar proteins containing an N-terminal propeptide, but not those with a C-terminal propeptide, are also present in these enlarged compartments. We hypothesize that AtSNX2b is involved in vesicular trafficking from endosomes to the vacuole.
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Affiliation(s)
- Nguyen Q Phan
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA
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24
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Onelli E, Prescianotto-Baschong C, Caccianiga M, Moscatelli A. Clathrin-dependent and independent endocytic pathways in tobacco protoplasts revealed by labelling with charged nanogold. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:3051-68. [PMID: 18603619 PMCID: PMC2504345 DOI: 10.1093/jxb/ern154] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 04/03/2008] [Accepted: 05/08/2008] [Indexed: 05/18/2023]
Abstract
Positively charged nanogold was used as a probe to trace the internalization of plasma membrane (PM) domains carrying negatively charged residues at an ultrastructural level. The probe revealed distinct endocytic pathways within tobacco protoplasts and allowed the morphology of the organelles involved in endocytosis to be characterized in great detail. Putative early endosomes with a tubulo-vesicular structure, similar to that observed in animal cells, are described and a new compartment, characterized by interconnected vesicles, was identified as a late endosome using the Arabidopsis anti-syntaxin family Syp-21 antibody. Endocytosis dissection using Brefeldin A (BFA), pulse chase, temperature- and energy-dependent experiments combined with quantitative analysis of nanogold particles in different compartments, suggested that recycling to the PM predominated with respect to degradation. Further experiments using ikarugamycin (IKA), an inhibitor of clathrin-dependent endocytosis, and negatively charged nanogold confirmed that distinct endocytic pathways coexist in tobacco protoplasts.
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25
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Sano T, Kutsuna N, Hasezawa S, Tanaka Y. Membrane trafficking in guard cells during stomatal movement: Application of an image processing technique. PLANT SIGNALING & BEHAVIOR 2008; 3:233-5. [PMID: 19704638 PMCID: PMC2634186 DOI: 10.4161/psb.3.4.5138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Accepted: 10/08/2007] [Indexed: 05/08/2023]
Abstract
Pairs of guard cells form small pores called stoma in the epidermis, and the reversible swelling and shrinking of these guard cells regulate the stomatal apertures. The well-documented changes in guard cell volume have been associated with their vacuolar structures. To investigate the contribution of the guard cell vacuoles to stomatal movement, the dynamics of these vacuolar structures were recently monitored during stomatal movement in vacuolar-membrane visualized Arabidopsis plants. Calculation of the vacuolar volume and surface area after reconstruction of three-dimensional images revealed a decrease in the vacuolar volume but an increase in the vacuolar surface area upon stomatal closure. These results implied the possible acceleration of membrane trafficking to the vacuole upon stomatal closure and membrane recycling from the vacuole to the plasma membrane upon stomatal opening. To clarify and quantify membrane trafficking during stomatal movement, we describe in this addendum our development of an improved image processing system.
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Affiliation(s)
- Toshio Sano
- Graduate School of Frontier Sciences; University of Tokyo; Kashiwa, Japan
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Yamazaki M, Shimada T, Takahashi H, Tamura K, Kondo M, Nishimura M, Hara-Nishimura I. Arabidopsis VPS35, a retromer component, is required for vacuolar protein sorting and involved in plant growth and leaf senescence. PLANT & CELL PHYSIOLOGY 2008; 49:142-56. [PMID: 18222962 DOI: 10.1093/pcp/pcn006] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The retromer complex is responsible for retrograde transport, which is coordinated with anterograde transport in the secretory pathway including vacuolar protein sorting. Yeast VPS35 is a component of the retromer complex that is essential for recognition of specific cargo molecules. The physiological function of VPS35 has not been determined in vacuolar protein sorting in higher organisms. Arabidopsis thaliana has three VPS35 homologs designated VPS35a, VPS35b and VPS35c. We isolated four vps35 mutants (vps35a-1, vps35b-1, vps35b-2 and vps35c-1) and then generated four double mutants and one triple mutant. vps35a-1 vps35c-1 exhibited no unusual phenotypes. On the other hand, vps35b-1 vps35c-1 and the triple mutant (vps35a-1 vps35b-2 vps35c-1) exhibited severe phenotypes: dwarfism, early leaf senescence and fragmentation of protein storage vacuoles (PSVs). In addition, these mutants mis-sorted storage proteins by secreting them out of the cells and accumulated a higher level of vacuolar sorting receptor (VSR) than the wild type. VPS35 was localized in pre-vacuolar compartments (PVCs), some of which contained VSR. VPS35 was immunoprecipitated with VPS29/MAG1, another component of the retromer complex. Our findings suggest that VPS35, mainly VPS35b, is involved in sorting proteins to PSVs in seeds, possibly by recycling VSR from PVCs to the Golgi complex, and is also involved in plant growth and senescence in vegetative organs.
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Affiliation(s)
- Misako Yamazaki
- Graduate School of Science, Kyoto University, Kyoto 606-8502 Japan
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27
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Laxmi A, Pan J, Morsy M, Chen R. Light plays an essential role in intracellular distribution of auxin efflux carrier PIN2 in Arabidopsis thaliana. PLoS One 2008; 3:e1510. [PMID: 18231596 PMCID: PMC2200863 DOI: 10.1371/journal.pone.0001510] [Citation(s) in RCA: 184] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Accepted: 12/29/2007] [Indexed: 11/18/2022] Open
Abstract
Background Light plays a key role in multiple plant developmental processes. It has been shown that root development is modulated by shoot-localized light signaling and requires shoot-derived transport of the plant hormone, auxin. However, the mechanism by which light regulates root development is not largely understood. In plants, the endogenous auxin, indole-3-acetic acid, is directionally transported by plasma-membrane (PM)-localized auxin influx and efflux carriers in transporting cells. Remarkably, the auxin efflux carrier PIN proteins exhibit asymmetric PM localization, determining the polarity of auxin transport. Similar to PM-resident receptors and transporters in animal and yeast cells, PIN proteins undergo constitutive cycling between the PM and endosomal compartments. Auxin plays multiple roles in PIN protein intracellular trafficking, inhibiting PIN2 endocytosis at some concentrations and promoting PIN2 degradation at others. However, how PIN proteins are turned over in plant cells is yet to be addressed. Methodology and Principle Findings Using laser confocal scanning microscopy, and physiological and molecular genetic approaches, here, we show that in dark-grown seedlings, the PM localization of auxin efflux carrier PIN2 was largely reduced, and, in addition, PIN2 signal was detected in vacuolar compartments. This is in contrast to light-grown seedlings where PIN2 was predominantly PM-localized. In light-grown plants after shift to dark or to continuous red or far-red light, PIN2 also accumulated in vacuolar compartments. We show that PIN2 vacuolar targeting was derived from the PM via endocytic trafficking and inhibited by HY5-dependent light signaling. In addition, the ubiquitin 26S proteasome is involved in the process, since its inhibition by mutations in COP9 and a proteasome inhibitor MG132 impaired the process. Conclusions and Significance Collectively, our data indicate that light plays an essential role in PIN2 intracellular trafficking, promoting PM-localization in the presence of light and, on the other hand, vacuolar targeting for protein degradation in the absence of light. Based on these results, we postulate that light regulation of root development is mediated at least in part by changes in the intracellular distribution of auxin efflux carriers, PIN proteins, in response to the light environment.
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Affiliation(s)
- Ashverya Laxmi
- Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, Oklahoma, United States of America
| | - Jianwei Pan
- Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, Oklahoma, United States of America
| | - Mustafa Morsy
- Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, Oklahoma, United States of America
| | - Rujin Chen
- Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, Oklahoma, United States of America
- * To whom correspondence should be addressed. E-mail:
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28
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Chow CM, Neto H, Foucart C, Moore I. Rab-A2 and Rab-A3 GTPases define a trans-golgi endosomal membrane domain in Arabidopsis that contributes substantially to the cell plate. THE PLANT CELL 2008; 20:101-23. [PMID: 18239134 PMCID: PMC2254926 DOI: 10.1105/tpc.107.052001] [Citation(s) in RCA: 215] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 12/10/2007] [Accepted: 01/13/2008] [Indexed: 05/18/2023]
Abstract
The Ypt3/Rab11/Rab25 subfamily of Rab GTPases has expanded greatly in Arabidopsis thaliana, comprising 26 members in six provisional subclasses, Rab-A1 to Rab-A6. We show that the Rab-A2 and Rab-A3 subclasses define a novel post-Golgi membrane domain in Arabidopsis root tips. The Rab-A2/A3 compartment was distinct from but often close to Golgi stacks and prevacuolar compartments and partly overlapped the VHA-a1 trans-Golgi compartment. It was also sensitive to brefeldin A and accumulated FM4-64 before prevacuolar compartments did. Mutations in RAB-A2a that were predicted to stabilize the GDP- or GTP-bound state shifted the location of the protein to the Golgi or plasma membrane, respectively. In mitosis, KNOLLE accumulated principally in the Rab-A2/A3 compartment. During cytokinesis, Rab-A2 and Rab-A3 proteins localized precisely to the growing margins of the cell plate, but VHA-a1, GNOM, and prevacuolar markers were excluded. Inducible expression of dominant-inhibitory mutants of RAB-A2a resulted in enlarged, polynucleate, meristematic cells with cell wall stubs. The Rab-A2/A3 compartment, therefore, is a trans-Golgi compartment that communicates with the plasma membrane and early endosomal system and contributes substantially to the cell plate. Despite the unique features of plant cytokinesis, membrane traffic to the division plane exhibits surprising molecular similarity across eukaryotic kingdoms in its reliance on Ypt3/Rab11/Rab-A GTPases.
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Affiliation(s)
- Cheung-Ming Chow
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
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29
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Yamada K, Fukao Y, Hayashi M, Fukazawa M, Suzuki I, Nishimura M. Cytosolic HSP90 regulates the heat shock response that is responsible for heat acclimation in Arabidopsis thaliana. J Biol Chem 2007; 282:37794-804. [PMID: 17965410 DOI: 10.1074/jbc.m707168200] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plant survival requires the ability to acclimate to heat. When plants are subjected to heat shock, the expression of various genes is induced, and the plants become tolerant of higher temperatures. We found that transient treatment with geldanamycin and radicicol, two heat shock protein 90 (HSP90) inhibitors, induced heat-inducible genes and heat acclimation in Arabidopsis thaliana seedlings. Heat shock reduced the activity of exogenously expressed glucocorticoid receptor (GR). Since GR activity depends on HSP90, this suggests that heat shock reduces cytosolic HSP90 activity in vivo. Microarray analysis revealed that many of the genes that are up-regulated by both heat shock and HSP90 inhibitors are involved in protein folding and degradation, suggesting that the activation of a protein maintenance system is a crucial part of this response. Most of these genes have heat shock response element-like motifs in their promoters, which suggests that heat shock transcription factor (HSF) is involved in the response to HSP90 inhibition. Several HSF genes are expressed constitutively in A. thaliana, including AtHsfA1d. Recombinant AtHsfA1d protein recognizes the heat shock response element motif and interacts with A. thaliana cytosolic HSP90, HSP90.2. Overexpression of a dominant negative form of HSP90.2 induced the heat-inducible gene. Thus, it appears that in the absence of heat shock, cytosolic HSP90 negatively regulates heat-inducible genes by actively suppressing HSF function. Upon heat shock, cytosolic HSP90 is transiently inactivated, which may lead to HSF activation.
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Affiliation(s)
- Kenji Yamada
- Department of Cell Biology, National Institute for Basic Biology, Aichi, Japan
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30
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Fuji K, Shimada T, Takahashi H, Tamura K, Koumoto Y, Utsumi S, Nishizawa K, Maruyama N, Hara-Nishimura I. Arabidopsis vacuolar sorting mutants (green fluorescent seed) can be identified efficiently by secretion of vacuole-targeted green fluorescent protein in their seeds. THE PLANT CELL 2007; 19:597-609. [PMID: 17293568 PMCID: PMC1867321 DOI: 10.1105/tpc.106.045997] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Two Arabidopsis thaliana genes have been shown to function in vacuolar sorting of seed storage proteins: a vacuolar sorting receptor, VSR1/ATELP1, and a retromer component, MAIGO1 (MAG1)/VPS29. Here, we show an efficient and simple method for isolating vacuolar sorting mutants of Arabidopsis. The method was based on two findings in this study. First, VSR1 functioned as a sorting receptor for beta-conglycinin by recognizing the vacuolar targeting signal. Second, when green fluorescent protein (GFP) fusion with the signal (GFP-CT24) was expressed in vsr1, mag1/vps29, and wild-type seeds, both vsr1and mag1/vps29 gave strongly fluorescent seeds but the wild type did not, suggesting that a defect in vacuolar sorting provided fluorescent seeds by the secretion of GFP-CT24 out of the cells. We mutagenized transformant seeds expressing GFP-CT24. From approximately 3,000,000 lines of M2 seeds, we obtained >100 fluorescent seeds and designated them green fluorescent seed (gfs) mutants. We report 10 gfs mutants, all of which caused missorting of storage proteins. We mapped gfs1 to VSR1, gfs2 to KAM2/GRV2, gfs10 to the At4g35870 gene encoding a novel membrane protein, and the others to different loci. This method should provide valuable insights into the complex molecular mechanisms underlying vacuolar sorting of storage proteins.
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Affiliation(s)
- Kentaro Fuji
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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31
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Hause G, Samaj J, Menzel D, Baluska F. Fine Structural Analysis of Brefeldin A-Induced Compartment Formation After High-Pressure Freeze Fixation of Maize Root Epidermis: Compound Exocytosis Resembling Cell Plate Formation during Cytokinesis. PLANT SIGNALING & BEHAVIOR 2006; 1:134-9. [PMID: 19521493 PMCID: PMC2635009 DOI: 10.4161/psb.1.3.2996] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Accepted: 05/09/2006] [Indexed: 05/23/2023]
Abstract
Formation of large perinuclear brefeldin A (BFA)-induced compartments is a characteristic feature of root apex cells, but it does not occur in shoot apex cells. BFA-induced compartments have been studied mostly using low resolution fluorescence microscopy techniques. Here, we have employed a high-resolution ultrastructural method based on ultra rapid freeze fixation of samples in order to study the formation of BFA-induced compartments in intact maize root epidermis cells in detail. This approach reveals five novel findings. Firstly, plant TGN/PGN elements are not tubular networks, as generally assumed, but rather vesicular compartments. Secondly, TGN/PGN vesicles interact with one another extensively via stalk-like connections and even fuse together via bridge-like structures. Thirdly, BFA-induced compartments are formed via extensive homotypic fusions of the TGN/PGN vesicles. Fourthly, multivesicular bodies (MVBs) are present within the BFA-induced compartments. Fifthly, mitochondria and small vacuoles accummulate abundantly around the large perinuclear BFA-induced compartments.
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Affiliation(s)
- G Hause
- Microscopy Unit; Biocenter; Martin-Luther-University Halle-Wittenberg; Halle, Germany
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32
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Dhonukshe P, Baluska F, Schlicht M, Hlavacka A, Samaj J, Friml J, Gadella TWJ. Endocytosis of Cell Surface Material Mediates Cell Plate Formation during Plant Cytokinesis. Dev Cell 2006; 10:137-50. [PMID: 16399085 DOI: 10.1016/j.devcel.2005.11.015] [Citation(s) in RCA: 222] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Revised: 09/15/2005] [Accepted: 11/14/2005] [Indexed: 01/12/2023]
Abstract
Dividing plant cells perform a remarkable task of building a new cell wall within the cytoplasm in a few minutes. A long-standing paradigm claims that this primordial cell wall, known as the cell plate, is generated by delivery of newly synthesized material from Golgi apparatus-originated secretory vesicles. Here, we show that, in diverse plant species, cell surface material, including plasma membrane proteins, cell wall components, and exogenously applied endocytic tracers, is rapidly delivered to the forming cell plate. Importantly, this occurs even when de novo protein synthesis is blocked. In addition, cytokinesis-specific syntaxin KNOLLE as well as plasma membrane (PM) resident proteins localize to endosomes that fuse to initiate the cell plate. The rate of endocytosis is strongly enhanced during cell plate formation, and its genetic or pharmacological inhibition leads to cytokinesis defects. Our results reveal that endocytic delivery of cell surface material significantly contributes to cell plate formation during plant cytokinesis.
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Affiliation(s)
- Pankaj Dhonukshe
- Section of Molecular Cytology and Center for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 316, 1098 SM Amsterdam, The Netherlands.
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Gao XQ, Li CG, Wei PC, Zhang XY, Chen J, Wang XC. The dynamic changes of tonoplasts in guard cells are important for stomatal movement in Vicia faba. PLANT PHYSIOLOGY 2005; 139:1207-16. [PMID: 16244153 PMCID: PMC1283759 DOI: 10.1104/pp.105.067520] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Revised: 08/26/2005] [Accepted: 08/26/2005] [Indexed: 05/04/2023]
Abstract
Stomatal movement is important for plants to exchange gas with environment. The regulation of stomatal movement allows optimizing photosynthesis and transpiration. Changes in vacuolar volume in guard cells are known to participate in this regulation. However, little has been known about the mechanism underlying the regulation of rapid changes in guard cell vacuolar volume. Here, we report that dynamic changes in the complex vacuolar membrane system play a role in the rapid changes of vacuolar volume in Vicia faba guard cells. The guard cells contained a great number of small vacuoles and various vacuolar membrane structures when stomata closed. The small vacuoles and complex membrane systems fused with each other or with the bigger vacuoles to generate large vacuoles during stomatal opening. Conversely, the large vacuoles split into smaller vacuoles and generated many complex membrane structures in the closing stomata. Vacuole fusion inhibitor, (2s,3s)-trans-epoxy-succinyl-l-leucylamido-3-methylbutane ethyl ester, inhibited stomatal opening significantly. Furthermore, an Arabidopsis (Arabidopsis thaliana) mutation of the SGR3 gene, which has a defect in vacuolar fusion, also led to retardation of stomatal opening. All these results suggest that the dynamic changes of the tonoplast are essential for enhancing stomatal movement.
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Affiliation(s)
- Xin-Qi Gao
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100094, People's Republic of China
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