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Zhang C, Chen L, Hou S. The emerging roles of clathrin-mediated endocytosis in plant development and stress responses. JOURNAL OF PLANT PHYSIOLOGY 2024; 295:154189. [PMID: 38432037 DOI: 10.1016/j.jplph.2024.154189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/22/2024] [Accepted: 02/01/2024] [Indexed: 03/05/2024]
Abstract
Clathrin-mediated endocytosis (CME) is a highly conserved pathway that plays a crucial role in the endocytosis of plasma membrane proteins in eukaryotic cells. The pathway is initiated when the adaptor protein complex 2 (AP2) and TPLATE complex (TPC) work together to recognize cargo proteins and recruit clathrin. This review provides a concise overview of the functions of each subunit of AP2 and TPC, and highlights the involvement of CME in various biological processes, such as pollen development, root development, nutrient transport, extracellular signal transduction, auxin polar transport, hyperosmotic stress, salinity stress, high ammonium stress, and disease resistance. Additionally, the review explores the regulation of CME by phytohormones, clathrin-mediated exocytosis (CMX), and AP2M phosphorylation. It also suggests potential future research directions for CME.
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Affiliation(s)
- Chi Zhang
- Key Laboratory of Gene Editing for Breeding, Gansu Province, Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Liang Chen
- Key Laboratory of Gene Editing for Breeding, Gansu Province, Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Suiwen Hou
- Key Laboratory of Gene Editing for Breeding, Gansu Province, Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
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2
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Yang L, Jiang L. The seven rice vacuolar sorting receptors localize to prevacuolar compartments. JOURNAL OF PLANT PHYSIOLOGY 2023; 291:154137. [PMID: 37984048 DOI: 10.1016/j.jplph.2023.154137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/24/2023] [Accepted: 11/06/2023] [Indexed: 11/22/2023]
Abstract
Vacuolar sorting is critically important in plants as it regulates the mobilization of proteins and plays a major role in important agricultural traits like yield and seed protein content. Vacuolar sorting receptors (VSRs) are integral membrane proteins that mediate protein trafficking from the Golgi apparatus to the vacuole via the intermediate membrane-bound prevacuolar compartment (PVC)/multivesicular body (MVB). VSR proteins, such as an 80 kD (BP-80) from pea, also serve as markers for PVC/MVB. Dissecting VSR-mediated protein trafficking pathways may provide ways to enhance agronomic traits and crop yield. Green fluorescence protein (GFP) fusions with the seven Arabidopsis (Arabidopsis thaliana) VSRs were previously shown to localize to PVCs in transgenic tobacco BY-2 cells. The Rice (Oryza sativa) genome contains seven VSRs (OsVSR1-7), but little is known about their subcellular localizations. Here we studied the subcellular localization of OsVSR1-7 b y using a reporter approach, in which GFP-OsVSR1-7 fusions containing the transmembrane domain (TMD) and cytoplasmic tail (CT) of individual OsVSR were expressed in the protoplasts of rice, transgenic tobacco BY-2 cells and transgenic rice plants. Immunofluorescent labelling studies and confocal laser scanning microscope observation demonstrated that the seven OsVSRs are localized to PVCs and form ring-like structures upon wortmannin treatment. Therefore, we have verified the subcellular localization of OsVSR1-7 in this study. The OsVSRs tagged with GFP can serve as PVCs/MVBs markers in rice for the future studies.
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Affiliation(s)
- Lei Yang
- The Engineering Research Institute of Agriculture and Forestry, Ludong University, Yantai, 264025, China; School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China.
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3
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Shao X, Xu H, Pimpl P. Nanobody-based VSR7 tracing shows clathrin-dependent TGN to Golgi recycling. Nat Commun 2023; 14:6926. [PMID: 37903761 PMCID: PMC10616157 DOI: 10.1038/s41467-023-42331-1] [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: 03/07/2023] [Accepted: 10/06/2023] [Indexed: 11/01/2023] Open
Abstract
Receptor-mediated transport of soluble proteins is nature's key to empowering eukaryotic cells to access a plethora of macromolecules, either by direct accumulation or as products from resulting biochemical pathways. The transport efficiency of these mechanisms results from the receptor's capability to capture, transport, and release ligands on the one hand and the cycling ability that allows for performing multiple rounds of ligand transport on the other. However, the plant VACUOLAR SORTING RECEPTOR (VSR) protein family is diverse, and their ligand-specificity and bidirectional trafficking routes and transport mechanisms remain highly controversial. Here we employ nanobody-epitope interaction-based molecular tools to assess the function of the VSR 7 in vivo. We demonstrate the specificity of the VSR7 for sequence-specific vacuolar sorting signals, and we trace its anterograde transport and retrograde recycling route. VSR7 localizes at the cis-Golgi apparatus at steady state conditions and transports ligands downstream to release them in the trans-Golgi network/early endosome (TGN/EE) before undergoing clathrin-dependent recycling from the TGN/EE back to the cis-Golgi.
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Affiliation(s)
- Xiaoyu Shao
- Harbin Institute of Technology, Harbin, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, Department of Biology, School of Life Sciences, Southern University of Science and Technology (SUSTech), Shenzhen, Guangdong, 518055, China
| | - Hao Xu
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, Department of Biology, School of Life Sciences, Southern University of Science and Technology (SUSTech), Shenzhen, Guangdong, 518055, China
| | - Peter Pimpl
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, Department of Biology, School of Life Sciences, Southern University of Science and Technology (SUSTech), Shenzhen, Guangdong, 518055, China.
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Zouhar J, Cao W, Shen J, Rojo E. Retrograde transport in plants: Circular economy in the endomembrane system. Eur J Cell Biol 2023; 102:151309. [PMID: 36933283 DOI: 10.1016/j.ejcb.2023.151309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/09/2023] [Accepted: 03/11/2023] [Indexed: 03/14/2023] Open
Abstract
The study of endomembrane trafficking is crucial for understanding how cells and whole organisms function. Moreover, there is a special interest in investigating endomembrane trafficking in plants, given its role in transport and accumulation of seed storage proteins and in secretion of cell wall material, arguably the two most essential commodities obtained from crops. The mechanisms of anterograde transport in the biosynthetic and endocytic pathways of plants have been thoroughly discussed in recent reviews, but, comparatively, retrograde trafficking pathways have received less attention. Retrograde trafficking is essential to recover membranes, retrieve proteins that have escaped from their intended localization, maintain homeostasis in maturing compartments, and recycle trafficking machinery for its reuse in anterograde transport reactions. Here, we review the current understanding on retrograde trafficking pathways in the endomembrane system of plants, discussing their integration with anterograde transport routes, describing conserved and plant-specific retrieval mechanisms at play, highlighting contentious issues and identifying open questions for future research.
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Affiliation(s)
- Jan Zouhar
- Central European Institute of Technology, Mendel University in Brno, CZ-61300 Brno, Czech Republic.
| | - Wenhan Cao
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, 311300 Hangzhou, China
| | - Jinbo Shen
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, 311300 Hangzhou, China.
| | - Enrique Rojo
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Cantoblanco, E-28049 Madrid, Spain.
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5
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Grones P, De Meyer A, Pleskot R, Mylle E, Kraus M, Vandorpe M, Yperman K, Eeckhout D, Dragwidge JM, Jiang Q, Nolf J, Pavie B, De Jaeger G, De Rybel B, Van Damme D. The endocytic TPLATE complex internalizes ubiquitinated plasma membrane cargo. NATURE PLANTS 2022; 8:1467-1483. [PMID: 36456802 PMCID: PMC7613989 DOI: 10.1038/s41477-022-01280-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 10/19/2022] [Indexed: 05/12/2023]
Abstract
Endocytosis controls the perception of stimuli by modulating protein abundance at the plasma membrane. In plants, clathrin-mediated endocytosis is the most prominent internalization pathway and relies on two multimeric adaptor complexes, the AP-2 and the TPLATE complex (TPC). Ubiquitination is a well-established modification triggering endocytosis of cargo proteins, but how this modification is recognized to initiate the endocytic event remains elusive. Here we show that TASH3, one of the large subunits of TPC, recognizes ubiquitinated cargo at the plasma membrane via its SH3 domain-containing appendage. TASH3 lacking this evolutionary specific appendage modification allows TPC formation but the plants show severely reduced endocytic densities, which correlates with reduced endocytic flux. Moreover, comparative plasma membrane proteomics identified differential accumulation of multiple ubiquitinated cargo proteins for which we confirm altered trafficking. Our findings position TPC as a key player for ubiquitinated cargo internalization, allowing future identification of target proteins under specific stress conditions.
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Affiliation(s)
- Peter Grones
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.
- Center for Plant Systems Biology, VIB, Ghent, Belgium.
| | - Andreas De Meyer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Roman Pleskot
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Evelien Mylle
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Michael Kraus
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Michael Vandorpe
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Klaas Yperman
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Dominique Eeckhout
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Jonathan Michael Dragwidge
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Qihang Jiang
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Jonah Nolf
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Benjamin Pavie
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- BioImaging Core, VIB, 9052 Ghent, Belgium
| | - Geert De Jaeger
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Bert De Rybel
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Daniël Van Damme
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.
- Center for Plant Systems Biology, VIB, Ghent, Belgium.
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6
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Liu C, Li Z, Tian D, Xu M, Pan J, Wu H, Wang C, Otegui MS. AP1/2β-mediated exocytosis of tapetum-specific transporters is required for pollen development in Arabidopsis thaliana. THE PLANT CELL 2022; 34:3961-3982. [PMID: 35766888 PMCID: PMC9516047 DOI: 10.1093/plcell/koac192] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 06/21/2022] [Indexed: 06/15/2023]
Abstract
AP-1 and AP-2 adaptor protein (AP) complexes mediate clathrin-dependent trafficking at the trans-Golgi network (TGN) and the plasma membrane, respectively. Whereas AP-1 is required for trafficking to plasma membrane and vacuoles, AP-2 mediates endocytosis. These AP complexes consist of four subunits (adaptins): two large subunits (β1 and γ for AP-1 and β2 and α for AP-2), a medium subunit μ, and a small subunit σ. In general, adaptins are unique to each AP complex, with the exception of β subunits that are shared by AP-1 and AP-2 in some invertebrates. Here, we show that the two putative Arabidopsis thaliana AP1/2β adaptins co-assemble with both AP-1 and AP-2 subunits and regulate exocytosis and endocytosis in root cells, consistent with their dual localization at the TGN and plasma membrane. Deletion of both β adaptins is lethal in plants. We identified a critical role of β adaptins in pollen wall formation and reproduction, involving the regulation of membrane trafficking in the tapetum and pollen germination. In tapetal cells, β adaptins localize almost exclusively to the TGN and mediate exocytosis of the plasma membrane transporters such as ATP-binding cassette (ABC)G9 and ABCG16. This study highlights the essential role of AP1/2β adaptins in plants and their specialized roles in specific cell types.
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Affiliation(s)
- Chan Liu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Zhimin Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Dan Tian
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Mei Xu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jianwei Pan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Haijun Wu
- Authors for correspondence: (M.S.O.); (C.W.); (H.W.)
| | - Chao Wang
- Authors for correspondence: (M.S.O.); (C.W.); (H.W.)
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7
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Xu M, Yan X, Wang Y, Liu C, Yang Q, Tian D, Bednarek SY, Pan J, Wang C. ADAPTOR PROTEIN-1 complex-mediated post-Golgi trafficking is critical for pollen wall development in Arabidopsis. THE NEW PHYTOLOGIST 2022; 235:472-487. [PMID: 35451504 PMCID: PMC9545562 DOI: 10.1111/nph.18170] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 03/09/2022] [Indexed: 05/16/2023]
Abstract
Primexine deposition is essential for the formation of pollen wall patterns and is precisely regulated by the tapetum and microspores. While tapetum- and/or microspore-localized proteins are required for primexine biosynthesis, how their trafficking is established and controlled is poorly understood. In Arabidopsis thaliana, AP1σ1 and AP1σ2, two genes encoding the σ subunit of the trans-Golgi network/early endosome (TGN/EE)-localized ADAPTOR PROTEIN-1 complex (AP-1), are partially redundant for plant viability, and the loss of AP1σ1 function reduces male fertility due to defective primexine formation. Here, we investigated the role of AP-1 in pollen wall formation. The deposition of Acyl-CoA SYNTHETASE5 (ACOS5) and type III LIPID TRANSFER PROTEINs (LTPs) secreted from the anther tapetum, which are involved in exine formation, were impaired in ap1σ1 mutants. In addition, the microspore plasma membrane (PM) protein RUPTURED POLLEN GRAIN1 (RPG1), which regulates primexine deposition, accumulated abnormally at the TGN/EE in ap1σ1 mutants. We show that AP-1μ recognizes the YXXΦ motif of RPG1, thereby regulating its PM abundance through endocytic trafficking, and that loss of AP1σ1 decreases the levels of other AP-1 subunits at the TGN/EE. Our observations show that AP-1-mediated post-Golgi trafficking plays a vital role in pollen wall development by regulating protein transport in tapetal cells and microspores.
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Affiliation(s)
- Mei Xu
- Ministry of Education Key Laboratory of Cell Activities and Stress AdaptationsSchool of Life SciencesLanzhou UniversityLanzhou730000China
| | - Xu Yan
- Ministry of Education Key Laboratory of Cell Activities and Stress AdaptationsSchool of Life SciencesLanzhou UniversityLanzhou730000China
| | - Yutong Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress AdaptationsSchool of Life SciencesLanzhou UniversityLanzhou730000China
| | - Chan Liu
- Ministry of Education Key Laboratory of Cell Activities and Stress AdaptationsSchool of Life SciencesLanzhou UniversityLanzhou730000China
| | - Qian Yang
- Ministry of Education Key Laboratory of Cell Activities and Stress AdaptationsSchool of Life SciencesLanzhou UniversityLanzhou730000China
| | - Dan Tian
- Ministry of Education Key Laboratory of Cell Activities and Stress AdaptationsSchool of Life SciencesLanzhou UniversityLanzhou730000China
| | | | - Jianwei Pan
- Ministry of Education Key Laboratory of Cell Activities and Stress AdaptationsSchool of Life SciencesLanzhou UniversityLanzhou730000China
| | - Chao Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress AdaptationsSchool of Life SciencesLanzhou UniversityLanzhou730000China
- College of Life SciencesShaoxing UniversityShaoxingZhejiang312000China
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8
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González Solís A, Berryman E, Otegui MS. Plant endosomes as protein sorting hubs. FEBS Lett 2022; 596:2288-2304. [PMID: 35689494 DOI: 10.1002/1873-3468.14425] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/28/2022] [Accepted: 05/31/2022] [Indexed: 01/10/2023]
Abstract
Endocytosis, secretion, and endosomal trafficking are key cellular processes that control the composition of the plasma membrane. Through the coordination of these trafficking pathways, cells can adjust the composition, localization, and turnover of proteins and lipids in response to developmental or environmental cues. Upon being incorporated into vesicles and internalized through endocytosis, plant plasma membrane proteins are delivered to the trans-Golgi network (TGN). At the TGN, plasma membrane proteins are recycled back to the plasma membrane or transferred to multivesicular endosomes (MVEs), where they are further sorted into intralumenal vesicles for degradation in the vacuole. Both types of plant endosomes, TGN and MVEs, act as sorting organelles for multiple endocytic, recycling, and secretory pathways. Molecular assemblies such as retromer, ESCRT (endosomal sorting complex required for transport) machinery, small GTPases, adaptor proteins, and SNAREs associate with specific domains of endosomal membranes to mediate different sorting and membrane-budding events. In this review, we discuss the mechanisms underlying the recognition and sorting of proteins at endosomes, membrane remodeling and budding, and their implications for cellular trafficking and physiological responses in plants.
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Affiliation(s)
- Ariadna González Solís
- Department of Botany and Center for Quantitative Cell Imaging, University of Wisconsin-Madison, WI, USA
| | - Elizabeth Berryman
- Department of Botany and Center for Quantitative Cell Imaging, University of Wisconsin-Madison, WI, USA
| | - Marisa S Otegui
- Department of Botany and Center for Quantitative Cell Imaging, University of Wisconsin-Madison, WI, USA
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9
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Arora D, Damme DV. Motif-based endomembrane trafficking. PLANT PHYSIOLOGY 2021; 186:221-238. [PMID: 33605419 PMCID: PMC8154067 DOI: 10.1093/plphys/kiab077] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/17/2021] [Indexed: 05/08/2023]
Abstract
Endomembrane trafficking, which allows proteins and lipids to flow between the different endomembrane compartments, largely occurs by vesicle-mediated transport. Transmembrane proteins intended for transport are concentrated into a vesicle or carrier by undulation of a donor membrane. This is followed by vesicle scission, uncoating, and finally, fusion at the target membrane. Three major trafficking pathways operate inside eukaryotic cells: anterograde, retrograde, and endocytic. Each pathway involves a unique set of machinery and coat proteins that pack the transmembrane proteins, along with their associated lipids, into specific carriers. Adaptor and coatomer complexes are major facilitators that function in anterograde transport and in endocytosis. These complexes recognize the transmembrane cargoes destined for transport and recruit the coat proteins that help form the carriers. These complexes use either linear motifs or posttranslational modifications to recognize the cargoes, which are then packaged and delivered along the trafficking pathways. In this review, we focus on the different trafficking complexes that share a common evolutionary branch in Arabidopsis (Arabidopsis thaliana), and we discuss up-to-date knowledge about the cargo recognition motifs they use.
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Affiliation(s)
- Deepanksha Arora
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent 9052, Belgium
| | - Daniёl Van Damme
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent 9052, Belgium
- Author for communication:
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10
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Zhang X, Li H, Lu H, Hwang I. The trafficking machinery of lytic and protein storage vacuoles: how much is shared and how much is distinct? JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3504-3512. [PMID: 33587748 DOI: 10.1093/jxb/erab067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 02/10/2021] [Indexed: 05/10/2023]
Abstract
Plant cells contain two types of vacuoles, the lytic vacuole (LV) and protein storage vacuole (PSV). LVs are present in vegetative cells, whereas PSVs are found in seed cells. The physiological functions of the two types of vacuole differ. Newly synthesized proteins must be transported to these vacuoles via protein trafficking through the endomembrane system for them to function. Recently, significant advances have been made in elucidating the molecular mechanisms of protein trafficking to these organelles. Despite these advances, the relationship between the trafficking mechanisms to the LV and PSV remains unclear. Some aspects of the trafficking mechanisms are common to both types of vacuole, but certain aspects are specific to trafficking to either the LV or PSV. In this review, we summarize recent findings on the components involved in protein trafficking to both the LV and PSV and compare them to examine the extent of overlap in the trafficking mechanisms. In addition, we discuss the interconnection between the LV and PSV provided by the protein trafficking machinery and the implications for the identity of these organelles.
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Affiliation(s)
- Xiuxiu Zhang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Hui Li
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Hai Lu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Inhwan Hwang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Department of Life Sciences, Pohang University of Science and Technology, 37673 Pohang, South Korea
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11
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Konarska A, Łotocka B. Glandular trichomes of Robinia viscosa Vent. var. hartwigii (Koehne) Ashe (Faboideae, Fabaceae)-morphology, histochemistry and ultrastructure. PLANTA 2020; 252:102. [PMID: 33180181 PMCID: PMC7661392 DOI: 10.1007/s00425-020-03513-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 11/04/2020] [Indexed: 05/31/2023]
Abstract
MAIN CONCLUSION Permanent glandular trichomes of Robinia viscosa var. hartwigii produce viscous secretion containing several secondary metabolites, as lipids, mucilage, flavonoids, proteins and alkaloids. Robinia viscosa var. hartwigii (Hartweg's locust) is an ornamental tree with high apicultural value. It can be planted in urban greenery and in degraded areas. The shoots, leaves, and inflorescences of this plant are equipped with numerous persistent glandular trichomes producing sticky secretion. The distribution, origin, development, morphology, anatomy, and ultrastructure of glandular trichomes of Hartweg's locust flowers as well as the localisation and composition of their secretory products were investigated for the first time. To this end, light, scanning, and transmission electron microscopy combined with histochemical and fluorescence techniques were used. The massive glandular trichomes differing in the distribution, length, and stage of development were built of a multicellular and multiseriate stalk and a multicellular head. The secretory cells in the stalk and head had large nuclei with nucleoli, numerous chloroplasts with thylakoids and starch grains, mitochondria, endoplasmic reticulum profiles, Golgi apparatus, vesicles, and multivesicular bodies. Many vacuoles contained phenolic compounds dissolved or forming various condensed deposits. The secretion components were transported through symplast elements, and the granulocrine and eccrine modes of nectar secretion were observed. The secretion was accumulated in the subcuticular space at the trichome apex and released through a pore in the cuticle. Histochemical and fluorescence assays showed that the trichomes and secretion contained lipophilic and polyphenol compounds, polysaccharides, proteins, and alkaloids. We suggest that these metabolites may serve an important function in protection of plants against biotic stress conditions and may also be a source of phytopharmaceuticals in the future.
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Affiliation(s)
- Agata Konarska
- Department of Botany and Plant Physiology, University of Life Sciences in Lublin, Akademicka 15, 20-950, Lublin, Poland.
| | - Barbara Łotocka
- Department of Botany, Warsaw, University of Life Sciences, Nowoursynowska 159, 02-776, Warsaw, Poland
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12
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Früholz S, Fäßler F, Kolukisaoglu Ü, Pimpl P. Nanobody-triggered lockdown of VSRs reveals ligand reloading in the Golgi. Nat Commun 2018; 9:643. [PMID: 29440677 PMCID: PMC5811495 DOI: 10.1038/s41467-018-02909-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 01/08/2018] [Indexed: 11/17/2022] Open
Abstract
Protein degradation in lytic compartments is crucial for eukaryotic cells. At the heart of this process, vacuolar sorting receptors (VSRs) bind soluble hydrolases in the secretory pathway and release them into the vacuolar route. Sorting efficiency is suggested to result from receptor recycling. However, how and to where plant VSRs recycle remains controversial. Here we present a nanobody-epitope interaction-based protein labeling and tracking approach to dissect their anterograde and retrograde transport routes in vivo. We simultaneously employ two different nanobody-epitope pairs: one for the location-specific post-translational fluorescence labeling of receptors and the other pair to trigger their compartment-specific lockdown via an endocytosed dual-epitope linker protein. We demonstrate VSR recycling from the TGN/EE, thereby identifying the cis-Golgi as the recycling target and show that recycled VSRs reload ligands. This is evidence that bidirectional VSR-mediated sorting of vacuolar proteins exists and occurs between the Golgi and the TGN/EE.
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Affiliation(s)
- Simone Früholz
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
| | - Florian Fäßler
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
| | - Üner Kolukisaoglu
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
| | - Peter Pimpl
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany.
- SUSTech-PKU Institute of Plant and Food Science (IPFS), Department of Biology, Southern University of Science and Technology (SUSTech), 1088 Xueyuan Rd, Shenzhen, 518055, China.
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Früholz S, Fäßler F, Kolukisaoglu Ü, Pimpl P. Nanobody-triggered lockdown of VSRs reveals ligand reloading in the Golgi. Nat Commun 2018. [PMID: 29440677 DOI: 10.1038/s41467-018-02909-2906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2023] Open
Abstract
Protein degradation in lytic compartments is crucial for eukaryotic cells. At the heart of this process, vacuolar sorting receptors (VSRs) bind soluble hydrolases in the secretory pathway and release them into the vacuolar route. Sorting efficiency is suggested to result from receptor recycling. However, how and to where plant VSRs recycle remains controversial. Here we present a nanobody-epitope interaction-based protein labeling and tracking approach to dissect their anterograde and retrograde transport routes in vivo. We simultaneously employ two different nanobody-epitope pairs: one for the location-specific post-translational fluorescence labeling of receptors and the other pair to trigger their compartment-specific lockdown via an endocytosed dual-epitope linker protein. We demonstrate VSR recycling from the TGN/EE, thereby identifying the cis-Golgi as the recycling target and show that recycled VSRs reload ligands. This is evidence that bidirectional VSR-mediated sorting of vacuolar proteins exists and occurs between the Golgi and the TGN/EE.
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Affiliation(s)
- Simone Früholz
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
| | - Florian Fäßler
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
| | - Üner Kolukisaoglu
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
| | - Peter Pimpl
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany.
- SUSTech-PKU Institute of Plant and Food Science (IPFS), Department of Biology, Southern University of Science and Technology (SUSTech), 1088 Xueyuan Rd, Shenzhen, 518055, China.
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Interchromosomal Transfer of Immune Regulation During Infection of Barley with the Powdery Mildew Pathogen. G3-GENES GENOMES GENETICS 2017; 7:3317-3329. [PMID: 28790145 PMCID: PMC5633382 DOI: 10.1534/g3.117.300125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Powdery mildew pathogens colonize over 9500 plant species, causing critical yield loss. The Ascomycete fungus, Blumeria graminis f. sp. hordei (Bgh), causes powdery mildew disease in barley (Hordeum vulgare L.). Successful infection begins with penetration of host epidermal cells, culminating in haustorial feeding structures, facilitating delivery of fungal effectors to the plant and exchange of nutrients from host to pathogen. We used expression Quantitative Trait Locus (eQTL) analysis to dissect the temporal control of immunity-associated gene expression in a doubled haploid barley population challenged with Bgh. Two highly significant regions possessing trans eQTL were identified near the telomeric ends of chromosomes (Chr) 2HL and 1HS. Within these regions reside diverse resistance loci derived from barley landrace H. laevigatum (MlLa) and H. vulgare cv. Algerian (Mla1), which associate with the altered expression of 961 and 3296 genes during fungal penetration of the host and haustorial development, respectively. Regulatory control of transcript levels for 299 of the 961 genes is reprioritized from MlLa on 2HL to Mla1 on 1HS as infection progresses, with 292 of the 299 alternating the allele responsible for higher expression, including Adaptin Protein-2 subunit μ AP2M and Vesicle Associated Membrane Protein VAMP72 subfamily members VAMP721/722. AP2M mediates effector-triggered immunity (ETI) via endocytosis of plasma membrane receptor components. VAMP721/722 and SNAP33 form a Soluble N-ethylmaleimide-sensitive factor Attachment Protein REceptor (SNARE) complex with SYP121 (PEN1), which is engaged in pathogen associated molecular pattern (PAMP)-triggered immunity via exocytosis. We postulate that genes regulated by alternate chromosomal positions are repurposed as part of a conserved immune complex to respond to different pathogen attack scenarios.
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15
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Barlow LD, Dacks JB. Seeing the endomembrane system for the trees: Evolutionary analysis highlights the importance of plants as models for eukaryotic membrane-trafficking. Semin Cell Dev Biol 2017; 80:142-152. [PMID: 28939036 DOI: 10.1016/j.semcdb.2017.09.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 08/22/2017] [Accepted: 09/19/2017] [Indexed: 12/12/2022]
Abstract
Plant cells show many signs of a unique evolutionary history. This is seen in the system of intracellular organelles and vesicle transport pathways plants use to traffic molecular cargo. Bioinformatic and cell biological work in this area is beginning to tackle the question of how plant cells have evolved, and what this tells us about the evolution of other eukaryotes. Key protein families with membrane trafficking function, including Rabs, SNAREs, vesicle coat proteins, and ArfGAPs, show patterns of evolution that indicate both specialization and conservation in plants. These changes are accompanied by changes at the level of organelles and trafficking pathways between them. Major specializations include losses of several ancient Rabs, novel functions of many proteins, and apparent modification of trafficking in endocytosis and cytokinesis. Nevertheless, plants show extensive conservation of ancestral membrane trafficking genes, and conservation of their ancestral function in most duplicates. Moreover, plants have retained several ancient membrane trafficking genes lost in the evolution of animals and fungi. Considering this, plants such as Arabidopsis are highly valuable for investigating not only plant-specific aspects of membrane trafficking, but also general eukaryotic mechanisms.
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Affiliation(s)
- L D Barlow
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta,5-31 Medical Sciences Building, Edmonton, Alberta, T6G 2H7, Canada
| | - J B Dacks
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta,5-31 Medical Sciences Building, Edmonton, Alberta, T6G 2H7, Canada.
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Konopka-Postupolska D, Clark G. Annexins as Overlooked Regulators of Membrane Trafficking in Plant Cells. Int J Mol Sci 2017; 18:E863. [PMID: 28422051 PMCID: PMC5412444 DOI: 10.3390/ijms18040863] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 04/03/2017] [Accepted: 04/06/2017] [Indexed: 12/11/2022] Open
Abstract
Annexins are an evolutionary conserved superfamily of proteins able to bind membrane phospholipids in a calcium-dependent manner. Their physiological roles are still being intensively examined and it seems that, despite their general structural similarity, individual proteins are specialized toward specific functions. However, due to their general ability to coordinate membranes in a calcium-sensitive fashion they are thought to participate in membrane flow. In this review, we present a summary of the current understanding of cellular transport in plant cells and consider the possible roles of annexins in different stages of vesicular transport.
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Affiliation(s)
- Dorota Konopka-Postupolska
- Plant Biochemistry Department, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland.
| | - Greg Clark
- Molecular, Cell, and Developmental Biology, University of Texas, Austin, TX 78712, USA.
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17
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Johnson A, Vert G. Single Event Resolution of Plant Plasma Membrane Protein Endocytosis by TIRF Microscopy. FRONTIERS IN PLANT SCIENCE 2017; 8:612. [PMID: 28484480 PMCID: PMC5401915 DOI: 10.3389/fpls.2017.00612] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 04/04/2017] [Indexed: 05/02/2023]
Abstract
Endocytosis is a key process in the internalization of extracellular materials and plasma membrane proteins, such as receptors and transporters, thereby controlling many aspects of cell signaling and cellular homeostasis. Endocytosis in plants has an essential role not only for basic cellular functions but also for growth and development, nutrient delivery, toxin avoidance, and pathogen defense. The precise mechanisms of endocytosis in plants remain quite elusive. The lack of direct visualization and examination of single events of endocytosis has greatly hampered our ability to precisely monitor the cell surface lifetime and the recruitment profile of proteins driving endocytosis or endocytosed cargos in plants. Here, we discuss the necessity to systematically implement total internal reflection fluorescence microcopy (TIRF) in the Plant Cell Biology community and present reliable protocols for high spatial and temporal imaging of endocytosis in plants using clathrin-mediated endocytosis as a test case, since it represents the major route for internalization of cell-surface proteins in plants. We developed a robust method to directly visualize cell surface proteins using TIRF microscopy combined to a high throughput, automated and unbiased analysis pipeline to determine the temporal recruitment profile of proteins to single sites of endocytosis, using the departure of clathrin as a physiological reference for scission. Using this 'departure assay', we assessed the recruitment of two different AP-2 subunits, alpha and mu, to the sites of endocytosis and found that AP2A1 was recruited in concert with clathrin, while AP2M was not. This validated approach therefore offers a powerful solution to better characterize the plant endocytic machinery and the dynamics of one's favorite cargo protein.
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18
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Occhialini A, Gouzerh G, Di Sansebastiano GP, Neuhaus JM. Dimerization of the Vacuolar Receptors AtRMR1 and -2 from Arabidopsis thaliana Contributes to Their Localization in the trans-Golgi Network. Int J Mol Sci 2016; 17:E1661. [PMID: 27706038 PMCID: PMC5085694 DOI: 10.3390/ijms17101661] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/23/2016] [Accepted: 09/23/2016] [Indexed: 01/03/2023] Open
Abstract
In Arabidopsis thaliana, different types of vacuolar receptors were discovered. The AtVSR (Vacuolar Sorting Receptor) receptors are well known to be involved in the traffic to lytic vacuole (LV), while few evidences demonstrate the involvement of the receptors from AtRMR family (Receptor Membrane RING-H2) in the traffic to the protein storage vacuole (PSV). In this study we focused on the localization of two members of AtRMR family, AtRMR1 and -2, and on the possible interaction between these two receptors in the plant secretory pathway. Our experiments with agroinfiltrated Nicotiana benthamiana leaves demonstrated that AtRMR1 was localized in the endoplasmic reticulum (ER), while AtRMR2 was targeted to the trans-Golgi network (TGN) due to the presence of a cytosolic 23-amino acid sequence linker. The fusion of this linker to an equivalent position in AtRMR1 targeted this receptor to the TGN, instead of the ER. By using a Bimolecular Fluorescent Complementation (BiFC) technique and experiments of co-localization, we demonstrated that AtRMR2 can make homodimers, and can also interact with AtRMR1 forming heterodimers that locate to the TGN. Such interaction studies strongly suggest that the transmembrane domain and the few amino acids surrounding it, including the sequence linker, are essential for dimerization. These results suggest a new model of AtRMR trafficking and dimerization in the plant secretory pathway.
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Affiliation(s)
- Alessandro Occhialini
- Plant Biology and Crop Science, Rothamsted Research, Harpenden, AL5 2JQ Herts, UK.
- Laboratory of Cell and Molecular Biology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2009 Neuchâtel, Switzerland.
| | - Guillaume Gouzerh
- Laboratory of Cell and Molecular Biology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2009 Neuchâtel, Switzerland.
| | - Gian-Pietro Di Sansebastiano
- DISTEBA, Department of Biological and Environmental Sciences and Technologies, University of Salento, Campus Ecotekne, 73100 Lecce, Italy.
| | - Jean-Marc Neuhaus
- Laboratory of Cell and Molecular Biology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2009 Neuchâtel, Switzerland.
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Yoshinari A, Fujimoto M, Ueda T, Inada N, Naito S, Takano J. DRP1-Dependent Endocytosis is Essential for Polar Localization and Boron-Induced Degradation of the Borate Transporter BOR1 in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2016; 57:1985-2000. [PMID: 27449211 DOI: 10.1093/pcp/pcw121] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 06/30/2016] [Indexed: 05/20/2023]
Abstract
Boron (B) is essential for plants but toxic in excess. The borate efflux transporter BOR1 is expressed in various root cells and localized to the inner/stele-side domain of the plasma membrane (PM) under low-B conditions. BOR1 is rapidly degraded through endocytosis upon sufficient B supply. The polar localization and degradation of BOR1 are considered important for efficient B translocation and avoidance of B toxicity, respectively. In this study, we first analyzed the subcellular localization of BOR1 in roots, cotyledons and hypocotyls, and revealed a polar localization in various cell types. We also found that the inner polarity of BOR1 is established after completion of cytokinesis in the root meristem. Moreover, variable-angle epifluorescence microscopy visualized BOR1-green fluorescent protein (GFP) as particles in the PM with significant lateral movements but in restricted areas. Importantly, a portion of BOR1-GFP particles co-localized with DYNAMIN-RELATED PROTEIN 1A (DRP1A), which is involved in scission of the clathrin-coated vesicles, and they disappeared together from the PM. To examine the contribution of DRP1A-mediated endocytosis to BOR1 localization and degradation, we developed an inducible expression system of the DRP1A K47A variant. The DRP1A variant prolonged the residence time of clathrin on the PM and inhibited endocytosis of membrane lipids. The dominant-negative DRP1A blocked endocytosis of BOR1 and disturbed its polar localization and B-induced degradation. Our results provided insight into the endocytic mechanisms that modulate the subcellular localization and abundance of a mineral transporter for nutrient homeostasis in plant cells.
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Affiliation(s)
- Akira Yoshinari
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, 599-8531 Japan Graduate School of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo, 060-8589 Japan
| | - Masaru Fujimoto
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657 Japan
| | - Takashi Ueda
- National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, 444-8585 Japan Japan Science and Technology Agency (JST), PRESTO, Honcho 4-1-8, Kawaguchi, 332-0012 Japan
| | - Noriko Inada
- Graduate School of Biological Sciences, Nara Institute of Sciences and Technology, Takayama 8916-5, Ikoma, Nara, 630-0192 Japan
| | - Satoshi Naito
- Research Faculty of Agriculture, Hokkaido University, Kita-10, Nishi-7, Kita-ku, Sapporo, 060-0810 Japan
| | - Junpei Takano
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, 599-8531 Japan
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Robinson DG, Neuhaus JM. Receptor-mediated sorting of soluble vacuolar proteins: myths, facts, and a new model. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:4435-49. [PMID: 27262127 DOI: 10.1093/jxb/erw222] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
To prevent their being released to the cell exterior, acid hydrolases are recognized by receptors at some point in the secretory pathway and diverted towards the lytic compartment of the cell (lysosome or vacuole). In animal cells, the receptor is called the mannosyl 6-phosphate receptor (MPR) and it binds hydrolase ligands in the trans-Golgi network (TGN). These ligands are then sequestered into clathrin-coated vesicles (CCVs) because of motifs in the cytosolic tail of the MPR which interact first with monomeric adaptors (Golgi-localized, Gamma-ear-containing, ARF-binding proteins, GGAs) and then with tetrameric (adaptin) adaptor complexes. The CCVs then fuse with an early endosome, whose more acidic lumen causes the ligands to dissociate. The MPRs are then recycled back to the TGN via retromer-coated carriers. Plants have vacuolar sorting receptors (VSRs) which were originally identified in CCVs isolated from pea (Pisum sativum L.) cotyledons. It was therefore assumed that VSRs would have an analogous function in plants to MPRs in animals. Although this dogma has enjoyed wide support over the last 20 years there are many inconsistencies. Recently, results have been published which are quite contrary to it. It now emerges that VSRs and their ligands can interact very early in the secretory pathway, and dissociate in the TGN, which, in contrast to its mammalian counterpart, has a pH of 5.5. Multivesicular endosomes in plants lack proton pump complexes and consequently have an almost neutral internal pH, which discounts them as organelles of pH-dependent receptor-ligand dissociation. These data force a critical re-evaluation of the role of CCVs at the TGN, especially considering that vacuolar cargo ligands have never been identified in them. We propose that one population of TGN-derived CCVs participate in retrograde transport of VSRs from the TGN. We also present a new model to explain how secretory and vacuolar cargo proteins are effectively separated after entering the late Golgi/TGN compartments.
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Affiliation(s)
- David G Robinson
- Centre for Organismal Studies (COS), University of Heidelberg, Germany
| | - Jean-Marc Neuhaus
- Institute of Biology, Laboratory of Cell and Molecular Biology, University of Neuchatel, Switzerland
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21
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Paiva EAS. How do secretory products cross the plant cell wall to be released? A new hypothesis involving cyclic mechanical actions of the protoplast. ANNALS OF BOTANY 2016; 117:533-40. [PMID: 26929201 PMCID: PMC4817504 DOI: 10.1093/aob/mcw012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 11/13/2015] [Accepted: 12/18/2015] [Indexed: 05/23/2023]
Abstract
BACKGROUND In plants, the products of secretory activity leave the protoplast and cross the plasma membrane by means of transporters, fusion with membranous vesicles or, less commonly, as result of disintegration of the cell. These mechanisms do not address an intriguing question: How do secretory products cross the cell wall? Furthermore, how do these substances reach the external surface of the plant body? Such diverse substances as oils, polysaccharides or nectar are forced to cross the cell wall and, in fact, do so. How are chemical materials that are repelled by the cell wall or that are sufficiently viscous to not cross passively released from plant cells? SCOPE AND CONCLUSIONS I propose a cell-cycle model developed based on observations of different secreting systems, some unpublished results and an extensive literature review, aiming to understand the processes involved in both the secretory process and the release of secretion products. In the absence of facilitated diffusion, a mechanical action of the protoplast is necessary to ensure that some substances can cross the cell wall. The mechanical action of the protoplast, in the form of successive cycles of contraction and expansion, causes the material accumulated in the periplasmic space to cross the cell wall and the cuticle. This action is particularly relevant for the release of lipids, resins and highly viscous hydrophilic secretions. The proposed cell-cycle model and the statements regarding exudate release will also apply to secretory glands not elaborated upon here. Continuous secretion of several days, as observed in extrafloral nectaries, salt glands and some mucilage-producing glands, is only possible because the process is cyclical.
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Affiliation(s)
- Elder Antônio Sousa Paiva
- Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, CP 486, Brazil
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22
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Isayenkov SV, Sekan AS, Sorochinsky BV, Blume YB. Molecular aspects of endosomal cellular transport. CYTOL GENET+ 2015. [DOI: 10.3103/s009545271503007x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Zouhar J, Sauer M. Helping hands for budding prospects: ENTH/ANTH/VHS accessory proteins in endocytosis, vacuolar transport, and secretion. THE PLANT CELL 2014; 26:4232-44. [PMID: 25415979 PMCID: PMC4277227 DOI: 10.1105/tpc.114.131680] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/31/2014] [Accepted: 11/13/2014] [Indexed: 05/18/2023]
Abstract
Coated vesicles provide a major mechanism for the transport of proteins through the endomembrane system of plants. Transport between the endoplasmic reticulum and the Golgi involves vesicles with COPI and COPII coats, whereas clathrin is the predominant coat in endocytosis and post-Golgi trafficking. Sorting of cargo, coat assembly, budding, and fission are all complex and tightly regulated processes that involve many proteins. The mechanisms and responsible factors are largely conserved in eukaryotes, and increasing organismal complexity tends to be associated with a greater numbers of individual family members. Among the key factors is the class of ENTH/ANTH/VHS domain-containing proteins, which link membrane subdomains, clathrin, and other adapter proteins involved in early steps of clathrin coated vesicle formation. More than 30 Arabidopsis thaliana proteins contain this domain, but their generally low sequence conservation has made functional classification difficult. Reports from the last two years have greatly expanded our knowledge of these proteins and suggest that ENTH/ANTH/VHS domain proteins are involved in various instances of clathrin-related endomembrane trafficking in plants. This review aims to summarize these new findings and discuss the broader context of clathrin-dependent plant vesicular transport.
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Affiliation(s)
- Jan Zouhar
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, 28223 Madrid, Spain
| | - Michael Sauer
- Institute for Bichemistry and Biology, University of Potsdam, 10627 Potsdam, Germany
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24
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Kang H, Hwang I. Vacuolar Sorting Receptor-Mediated Trafficking of Soluble Vacuolar Proteins in Plant Cells. PLANTS 2014; 3:392-408. [PMID: 27135510 PMCID: PMC4844349 DOI: 10.3390/plants3030392] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 08/18/2014] [Accepted: 08/18/2014] [Indexed: 01/13/2023]
Abstract
Vacuoles are one of the most prominent organelles in plant cells, and they play various important roles, such as degradation of waste materials, storage of ions and metabolites, and maintaining turgor. During the past two decades, numerous advances have been made in understanding how proteins are specifically delivered to the vacuole. One of the most crucial steps in this process is specific sorting of soluble vacuolar proteins. Vacuolar sorting receptors (VSRs), which are type I membrane proteins, are involved in the sorting and packaging of soluble vacuolar proteins into transport vesicles with the help of various accessory proteins. To date, large amounts of data have led to the development of two different models describing VSR-mediated vacuolar trafficking that are radically different in multiple ways, particularly regarding the location of cargo binding to, and release from, the VSR and the types of carriers utilized. In this review, we summarize current literature aimed at elucidating VSR-mediated vacuolar trafficking and compare the two models with respect to the sorting signals of vacuolar proteins, as well as the molecular machinery involved in VSR-mediated vacuolar trafficking and its action mechanisms.
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Affiliation(s)
- Hyangju Kang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Inhwan Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea.
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea.
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25
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Paul P, Simm S, Mirus O, Scharf KD, Fragkostefanakis S, Schleiff E. The complexity of vesicle transport factors in plants examined by orthology search. PLoS One 2014; 9:e97745. [PMID: 24844592 PMCID: PMC4028247 DOI: 10.1371/journal.pone.0097745] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 04/24/2014] [Indexed: 11/18/2022] Open
Abstract
Vesicle transport is a central process to ensure protein and lipid distribution in eukaryotic cells. The current knowledge on the molecular components and mechanisms of this process is majorly based on studies in Saccharomyces cerevisiae and Arabidopsis thaliana, which revealed 240 different proteinaceous factors either experimentally proven or predicted to be involved in vesicle transport. In here, we performed an orthologue search using two different algorithms to identify the components of the secretory pathway in yeast and 14 plant genomes by using the 'core-set' of 240 factors as bait. We identified 4021 orthologues and (co-)orthologues in the discussed plant species accounting for components of COP-II, COP-I, Clathrin Coated Vesicles, Retromers and ESCRTs, Rab GTPases, Tethering factors and SNAREs. In plants, we observed a significantly higher number of (co-)orthologues than yeast, while only 8 tethering factors from yeast seem to be absent in the analyzed plant genomes. To link the identified (co-)orthologues to vesicle transport, the domain architecture of the proteins from yeast, genetic model plant A. thaliana and agriculturally relevant crop Solanum lycopersicum has been inspected. For the orthologous groups containing (co-)orthologues from yeast, A. thaliana and S. lycopersicum, we observed the same domain architecture for 79% (416/527) of the (co-)orthologues, which documents a very high conservation of this process. Further, publically available tissue-specific expression profiles for a subset of (co-)orthologues found in A. thaliana and S. lycopersicum suggest that some (co-)orthologues are involved in tissue-specific functions. Inspection of localization of the (co-)orthologues based on available proteome data or localization predictions lead to the assignment of plastid- as well as mitochondrial localized (co-)orthologues of vesicle transport factors and the relevance of this is discussed.
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Affiliation(s)
- Puneet Paul
- Department of Biosciences Molecular Cell Biology of Plants
| | - Stefan Simm
- Department of Biosciences Molecular Cell Biology of Plants
| | - Oliver Mirus
- Department of Biosciences Molecular Cell Biology of Plants
| | | | | | - Enrico Schleiff
- Department of Biosciences Molecular Cell Biology of Plants
- Cluster of Excellence Frankfurt
- Center of Membrane Proteomics; Goethe University Frankfurt, Frankfurt/Main, Germany
- * E-mail:
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26
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Ganguly A, Park M, Kesawat MS, Cho HT. Functional Analysis of the Hydrophilic Loop in Intracellular Trafficking of Arabidopsis PIN-FORMED Proteins. THE PLANT CELL 2014; 26:1570-1585. [PMID: 24692422 PMCID: PMC4036572 DOI: 10.1105/tpc.113.118422] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 03/03/2014] [Accepted: 03/18/2014] [Indexed: 05/18/2023]
Abstract
Different PIN-FORMED proteins (PINs) contribute to intercellular and intracellular auxin transport, depending on their distinctive subcellular localizations. Arabidopsis thaliana PINs with a long hydrophilic loop (HL) (PIN1 to PIN4 and PIN7; long PINs) localize predominantly to the plasma membrane (PM), whereas short PINs (PIN5 and PIN8) localize predominantly to internal compartments. However, the subcellular localization of the short PINs has been observed mostly for PINs ectopically expressed in different cell types, and the role of the HL in PIN trafficking remains unclear. Here, we tested whether a long PIN-HL can provide its original molecular cues to a short PIN by transplanting the HL. The transplanted long PIN2-HL was sufficient for phosphorylation and PM trafficking of the chimeric PIN5:PIN2-HL but failed to provide the characteristic polarity of PIN2. Unlike previous observations, PIN5 showed clear PM localization in diverse cell types where PIN5 is natively or ectopically expressed and even polar PM localization in one cell type. Furthermore, in the root epidermis, the subcellular localization of PIN5 switched from PM to internal compartments according to the developmental stage. Our results suggest that the long PIN-HL is partially modular for the trafficking behavior of PINs and that the intracellular trafficking of PIN is plastic depending on cell type and developmental stage.
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Affiliation(s)
- Anindya Ganguly
- Department of Biological Sciences and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-742, Korea
| | - Minho Park
- Department of Biological Sciences and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-742, Korea
| | - Mahipal Singh Kesawat
- Department of Biological Sciences and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-742, Korea
| | - Hyung-Taeg Cho
- Department of Biological Sciences and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-742, Korea
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27
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Robinson DG, Pimpl P. Clathrin and post-Golgi trafficking: a very complicated issue. TRENDS IN PLANT SCIENCE 2014; 19:134-9. [PMID: 24263003 DOI: 10.1016/j.tplants.2013.10.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 10/18/2013] [Accepted: 10/21/2013] [Indexed: 05/21/2023]
Abstract
Clathrin-coated vesicles (CCVs) are formed at the plasma membrane and act as vectors for endocytosis. They also assemble at the trans-Golgi network (TGN), but their exact function at this organelle is unclear. Recent studies have examined the effects on vacuolar and secretory protein transport of knockout mutations of the adaptor protein 1 (AP1) μ-adaptin subunit AP1M, but these investigations do not clarify the situation. These mutations lead to the abrogation of multiple trafficking pathways at the TGN and cannot be used as evidence in favour of CCVs being agents for receptor-mediated export of vacuolar proteins out of the TGN. This transport process could just as easily occur through the maturation of the TGN into intermediate compartments that subsequently fuse with the vacuole.
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Affiliation(s)
- David G Robinson
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany.
| | - Peter Pimpl
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany
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28
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Gershlick DC, de Marcos Lousa C, Foresti O, Lee AJ, Pereira EA, daSilva LL, Bottanelli F, Denecke J. Golgi-dependent transport of vacuolar sorting receptors is regulated by COPII, AP1, and AP4 protein complexes in tobacco. THE PLANT CELL 2014; 26:1308-29. [PMID: 24642936 PMCID: PMC4001386 DOI: 10.1105/tpc.113.122226] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/10/2014] [Accepted: 02/18/2014] [Indexed: 05/02/2023]
Abstract
The cycling of vacuolar sorting receptors (VSRs) between early and late secretory pathway compartments is regulated by signals in the cytosolic tail, but the exact pathway is controversial. Here, we show that receptor targeting in tobacco (Nicotiana tabacum) initially involves a canonical coat protein complex II-dependent endoplasmic reticulum-to-Golgi bulk flow route and that VSR-ligand interactions in the cis-Golgi play an important role in vacuolar sorting. We also show that a conserved Glu is required but not sufficient for rate-limiting YXX-mediated receptor trafficking. Protein-protein interaction studies show that the VSR tail interacts with the μ-subunits of plant or mammalian clathrin adaptor complex AP1 and plant AP4 but not that of plant and mammalian AP2. Mutants causing a detour of full-length receptors via the cell surface invariantly cause the secretion of VSR ligands. Therefore, we propose that cycling via the plasma membrane is unlikely to play a role in biosynthetic vacuolar sorting under normal physiological conditions and that the conserved Ile-Met motif is mainly used to recover mistargeted receptors. This occurs via a fundamentally different pathway from the prevacuolar compartment that does not mediate recycling. The role of clathrin and clathrin-independent pathways in vacuolar targeting is discussed.
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Affiliation(s)
- David C. Gershlick
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Carine de Marcos Lousa
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | - Andrew J. Lee
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | | | | | - Jurgen Denecke
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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29
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Robinson DG, Pimpl P. Receptor-mediated transport of vacuolar proteins: a critical analysis and a new model. PROTOPLASMA 2014; 251:247-64. [PMID: 24019013 DOI: 10.1007/s00709-013-0542-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 08/20/2013] [Indexed: 05/20/2023]
Abstract
In this article we challenge the widely accepted view that receptors for soluble vacuolar proteins (VSRs) bind to their ligands at the trans-Golgi network (TGN) and transport this cargo via clathrin-coated vesicles (CCV) to a multivesicular prevacuolar compartment. This notion, which we term the "classical model" for vacuolar protein sorting, further assumes that low pH in the prevacuolar compartment causes VSR-ligand dissociation, resulting in a retromer-mediated retrieval of the VSRs to the TGN. We have carefully evaluated the literature with respect to morphology and function of the compartments involved, localization of key components of the sorting machinery, and conclude that there is little direct evidence in its favour. Firstly, unlike mammalian cells where the sorting receptor for lysosomal hydrolases recognizes its ligand in the TGN, the available data suggests that in plants VSRs interact with vacuolar cargo ligands already in the endoplasmic reticulum. Secondly, the evidence supporting the packaging of VSR-ligand complexes into CCV at the TGN is not conclusive. Thirdly, the prevacuolar compartment appears to have a pH unsuitable for VSR-ligand dissociation and lacks the retromer core and the sorting nexins needed for VSR recycling. We present an alternative model for protein sorting in the TGN that draws attention to the much overlooked role of Ca(2+) in VSR-ligand interactions and which may possibly also be a factor in the sequestration of secretory proteins.
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Affiliation(s)
- David G Robinson
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
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30
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Hu G, Suo Y, Huang J. A crucial role of the RGS domain in trans-Golgi network export of AtRGS1 in the protein secretory pathway. MOLECULAR PLANT 2013; 6:1933-1944. [PMID: 23793400 DOI: 10.1093/mp/sst109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The secretory pathway is responsible for the transport of newly synthesized transmembrane proteins from the endoplasmic reticulum to their destinations via the Golgi/trans-Golgi network (TGN). Cargo proteins at each station are actively sorted by specific sorting signals on the cargo and the corresponding coat complexes. Here, we used the Arabidopsis regulator of G-protein signaling (AtRGS1), which contains an N-terminal potentially sensing glucose seven-transmembrane domain and a C-terminal RGS domain, as a model to uncover sorting motifs required for its cell surface expression. Expression of wild-type and truncated or mutated AtRGS1 fluorescent fusion proteins identified two cysteine residues in the extracellular N-terminus that are essential for endoplasmic reticulum exit and/or correct folding of AtRGS1. The linker between the seven-transmembrane and RGS domains contains an endoplasmic reticulum export signal, whereas the C-terminus is dispensable for the plasma membrane expression of AtRGS1. Interestingly, deletion of the RGS domain results in Golgi/TGN localization of the truncated AtRGS1. Further analysis using site-directed mutagenesis showed that a tyrosine-based motif embedded in the RGS domain is essential for Golgi/TGN export of AtRGS1. These results reveal a new role for the RGS domain in regulating AtRGS1 trafficking from the Golgi/TGN to the plasma membrane and explain the interaction between the seven-transmembrane and RGS domains.
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Affiliation(s)
- Guangzhen Hu
- National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Feng Lin Road, Shanghai 200032, China
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31
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Fan L, Hao H, Xue Y, Zhang L, Song K, Ding Z, Botella MA, Wang H, Lin J. Dynamic analysis of Arabidopsis AP2 σ subunit reveals a key role in clathrin-mediated endocytosis and plant development. Development 2013; 140:3826-37. [DOI: 10.1242/dev.095711] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Clathrin-mediated endocytosis, which depends on the AP2 complex, plays an essential role in many cellular and developmental processes in mammalian cells. However, the function of the AP2 complex in plants remains largely unexplored. Here, we show in Arabidopsis that the AP2 σ subunit mutant (ap2 σ) displays various developmental defects that are similar to those of mutants defective in auxin transport and/or signaling, including single, trumpet-shaped and triple cotyledons, impaired vascular pattern, reduced vegetative growth, defective silique development and drastically reduced fertility. We demonstrate that AP2 σ is closely associated and physically interacts with the clathrin light chain (CLC) in vivo using fluorescence cross-correlation spectroscopy (FCCS), protein proximity analyses and co-immunoprecipitation assays. Using variable-angle total internal reflection fluorescence microscopy (VA-TIRFM), we show that AP2 σ-mCherry spots colocalize with CLC-EGFP at the plasma membrane, and that AP2 σ-mCherry fluorescence appears and disappears before CLC-EGFP fluorescence. The density and turnover rate of the CLC-EGFP spots are significantly reduced in the ap2 σ mutant. The internalization and recycling of the endocytic tracer FM4-64 and the auxin efflux carrier protein PIN1 are also significantly reduced in the ap2 σ mutant. Further, the polar localization of PIN1-GFP is significantly disrupted during embryogenesis in the ap2 σ mutant. Taken together, our results support an essential role of AP2 σ in the assembly of a functional AP2 complex in plants, which is required for clathrin-mediated endocytosis, polar auxin transport and plant growth regulation.
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Affiliation(s)
- Lusheng Fan
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huaiqing Hao
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yiqun Xue
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liang Zhang
- College of Life Science, Henan Normal University, Xinxiang 453007, China
| | - Kai Song
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhaojun Ding
- School of Life Sciences, Shandong University, Jinan 250100, China
| | - Miguel A. Botella
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, 29071 Malaga, Spain
| | - Haiyang Wang
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA
| | - Jinxing Lin
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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32
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Bashline L, Li S, Anderson CT, Lei L, Gu Y. The endocytosis of cellulose synthase in Arabidopsis is dependent on μ2, a clathrin-mediated endocytosis adaptin. PLANT PHYSIOLOGY 2013; 163:150-60. [PMID: 23843604 PMCID: PMC3762637 DOI: 10.1104/pp.113.221234] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 07/08/2013] [Indexed: 05/18/2023]
Abstract
Clathrin-mediated endocytosis (CME) is the best-characterized type of endocytosis in eukaryotic cells. Plants appear to possess all of the molecular components necessary to carry out CME; however, functional characterization of the components is still in its infancy. A yeast two-hybrid screen identified μ2 as a putative interaction partner of CELLULOSE SYNTHASE6 (CESA6). Arabidopsis (Arabidopsis thaliana) μ2 is homologous to the medium subunit 2 of the mammalian ADAPTOR PROTEIN COMPLEX2 (AP2). In mammals, the AP2 complex acts as the central hub of CME by docking to the plasma membrane while concomitantly recruiting cargo proteins, clathrin triskelia, and accessory proteins to the sites of endocytosis. We confirmed that μ2 interacts with multiple CESA proteins through the μ-homology domain of μ2, which is involved in specific interactions with endocytic cargo proteins in mammals. Consistent with its role in mediating the endocytosis of cargos at the plasma membrane, μ2-YELLOW FLUORESCENT PROTEIN localized to transient foci at the plasma membrane, and loss of μ2 resulted in defects in bulk endocytosis. Furthermore, loss of μ2 led to increased accumulation of YELLOW FLUORESCENT PROTEIN-CESA6 particles at the plasma membrane. Our results suggest that CESA represents a new class of CME cargo proteins and that plant cells might regulate cellulose synthesis by controlling the abundance of active CESA complexes at the plasma membrane through CME.
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33
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Di Rubbo S, Irani NG, Kim SY, Xu ZY, Gadeyne A, Dejonghe W, Vanhoutte I, Persiau G, Eeckhout D, Simon S, Song K, Kleine-Vehn J, Friml J, De Jaeger G, Van Damme D, Hwang I, Russinova E. The clathrin adaptor complex AP-2 mediates endocytosis of brassinosteroid insensitive1 in Arabidopsis. THE PLANT CELL 2013; 25:2986-97. [PMID: 23975899 PMCID: PMC3784593 DOI: 10.1105/tpc.113.114058] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 07/22/2013] [Accepted: 08/06/2013] [Indexed: 05/18/2023]
Abstract
Clathrin-mediated endocytosis (CME) regulates many aspects of plant development, including hormone signaling and responses to environmental stresses. Despite the importance of this process, the machinery that regulates CME in plants is largely unknown. In mammals, the heterotetrameric adaptor protein complex-2 (AP-2) is required for the formation of clathrin-coated vesicles at the plasma membrane (PM). Although the existence of AP-2 has been predicted in Arabidopsis thaliana, the biochemistry and functionality of the complex is still uncharacterized. Here, we identified all the subunits of the Arabidopsis AP-2 by tandem affinity purification and found that one of the large AP-2 subunits, AP2A1, localized at the PM and interacted with clathrin. Furthermore, endocytosis of the leucine-rich repeat receptor kinase, brassinosteroid insensitive1 (BRI1), was shown to depend on AP-2. Knockdown of the two Arabidopsis AP2A genes or overexpression of a dominant-negative version of the medium AP-2 subunit, AP2M, impaired BRI1 endocytosis and enhanced the brassinosteroid signaling. Our data reveal that the CME machinery in Arabidopsis is evolutionarily conserved and that AP-2 functions in receptor-mediated endocytosis.
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Affiliation(s)
- Simone Di Rubbo
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Niloufer G. Irani
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Soo Youn Kim
- Division of Molecules and Life Sciences and Center for Plant Intracellular Trafficking, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Zheng-Yi Xu
- Division of Molecules and Life Sciences and Center for Plant Intracellular Trafficking, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Astrid Gadeyne
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Wim Dejonghe
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Isabelle Vanhoutte
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Geert Persiau
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Dominique Eeckhout
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Sibu Simon
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Kyungyoung Song
- Division of Molecules and Life Sciences and Center for Plant Intracellular Trafficking, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Jürgen Kleine-Vehn
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Jiří Friml
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Geert De Jaeger
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Daniël Van Damme
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Inhwan Hwang
- Division of Molecules and Life Sciences and Center for Plant Intracellular Trafficking, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Eugenia Russinova
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Address correspondence to
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34
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Xiang L, Van den Ende W. Trafficking of plant vacuolar invertases: from a membrane-anchored to a soluble status. Understanding sorting information in their complex N-terminal motifs. PLANT & CELL PHYSIOLOGY 2013; 54:1263-1277. [PMID: 23737500 DOI: 10.1093/pcp/pct075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Vacuolar invertases (VIs) are highly expressed in young tissues and organs. They may have a substantial regulatory influence on whole-plant metabolism as well as on photosynthetic efficiency. Therefore, they are emerging as potentially interesting biotechnological targets to increase plant biomass production, especially under stress. On the one hand, VIs are well known as soluble and extractable proteins. On the other hand, they contain complex N-terminal propeptide (NTPP) regions with a basic region (BR) and a transmembrane domain (TMD). Here we analyzed in depth the Arabidopsis thaliana VI2 (AtVI2) NTPP by mutagenesis. It was found that correct sorting to the lytic vacuole (LV) depends on the presence of intact dileucine (SSDALLPIS), BR (RRRR) and TMD motifs. AtVI2 remains inserted into membranes on its way to the LV, and the classical sorting pathway (endoplasmic reticulum→Golgi→LV) is followed. However, our data suggest that VIs might follow an alternative, adaptor protein 3 (AP3)-dependent route as well. Membrane-anchored transport and a direct recognition of the dileucine motif in the NTPP of VIs might have evolved as a simple and more efficient sorting mechanism as compared with the vacuolar sorting receptor 1/binding protein of 80 kDa (VSR1/BP80)-dependent sorting mechanism followed by those proteins that travel to the vacuole as soluble proteins.
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Affiliation(s)
- Li Xiang
- Biology Department, Laboratory for Molecular Plant Biology, KU Leuven, Kasteelpark Arenberg 31, Box 2434, B-3001 Heverlee, Belgium
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35
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Arabidopsis μ-adaptin subunit AP1M of adaptor protein complex 1 mediates late secretory and vacuolar traffic and is required for growth. Proc Natl Acad Sci U S A 2013; 110:10318-23. [PMID: 23733933 DOI: 10.1073/pnas.1300460110] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Adaptor protein (AP) complexes are the predominant coat proteins of membrane vesicles in post-Golgi trafficking of mammalian cells. Each AP complex contains a specific medium subunit, μ-adaptin, that selects cargo proteins bearing sequence-specific sorting motifs. Much less is known about the AP complexes and their μ subunits in plants. Because of uncertain homology, the μ-adaptins of Arabidopsis have been designated muA through muD [Happel et al. (2004) Plant J 37(5):678-693]. Furthermore, only muD has been assigned to a specific AP complex, AP-3, involved in Golgi-vacuolar trafficking [Niihama et al. (2009) Plant Cell Physiol 50(12):2057-2068, Zwiewka et al. (2011) Cell Res 21(12):1711-1722, and Wolfenstetter et al. (2012) Plant Cell 24(1):215-232]. In contrast, the μ subunit of neither the post-Golgi trafficking AP-1 complex nor the endocytic AP-2 complex has been identified. Here, we report the functional analysis of redundant AP-1 μ-adaptins AP1M1 (also known as muB1) and AP1M2 (also known as muB2). Coimmunoprecipitation revealed that both AP1M2 and its less strongly expressed isoform AP1M1 are complexed with the large subunit γ-adaptin of AP-1. In addition, AP1M2 was localized at or near the trans-Golgi network. Knockout mutations of AP1M2 impaired pollen function and arrested plant growth whereas the ap1m1 ap1m2 double mutant was nearly pollen-lethal. At the cellular level, the absence of AP1M2 entailed inhibition of multiple trafficking pathways from the trans-Golgi network to the vacuole and to the plasma membrane in interphase and to the plane of cell division in cytokinesis. Thus, AP-1 is crucial in post-Golgi trafficking in plant cells and required for cell division and plant growth.
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36
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Teh OK, Shimono Y, Shirakawa M, Fukao Y, Tamura K, Shimada T, Hara-Nishimura I. The AP-1 µ Adaptin is Required for KNOLLE Localization at the Cell Plate to Mediate Cytokinesis in Arabidopsis. ACTA ACUST UNITED AC 2013; 54:838-47. [DOI: 10.1093/pcp/pct048] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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37
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Xiang L, Etxeberria E, den Ende W. Vacuolar protein sorting mechanisms in plants. FEBS J 2013; 280:979-93. [DOI: 10.1111/febs.12092] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 11/08/2012] [Accepted: 12/11/2012] [Indexed: 01/12/2023]
Affiliation(s)
- Li Xiang
- Laboratory of Molecular Plant Biology KU Leuven Belgium
| | - Ed Etxeberria
- Horticulture Department Citrus Research and Education Center University of Florida Lake Alfred FL USA
| | - Wim den Ende
- Laboratory of Molecular Plant Biology KU Leuven Belgium
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38
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Tian M, Xie Q. Non-26S proteasome proteolytic role of ubiquitin in plant endocytosis and endosomal trafficking(F). JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:54-63. [PMID: 23137267 DOI: 10.1111/jipb.12007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The 76 amino acid protein ubiquitin (Ub) is highly conserved in all eukaryotic species. It plays important roles in many cellular processes by covalently attaching to the target proteins. The best known function of Ub is marking substrate proteins for degradation by the 26S proteasome. In fact, other consequences of ubiquitination have been discovered in yeast and mammals, such as membrane trafficking, DNA repair, chromatin modification, and protein kinase activation. The common mechanism underlying these processes is that Ub serves as a signal to sort proteins to the vacuoles or lysosomes for degradation as opposed to 26S proteasome-dependent degradation. To date, several reports have indicated that a similar function of Ub also exists in plants. This review focuses on a summary and analysis of the recent research progress on Ub acting as a signal to mediate endocytosis and endosomal trafficking in plants.
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Affiliation(s)
- Miaomiao Tian
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
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39
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Beck M, Heard W, Mbengue M, Robatzek S. The INs and OUTs of pattern recognition receptors at the cell surface. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:367-74. [PMID: 22664220 DOI: 10.1016/j.pbi.2012.05.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 05/08/2012] [Accepted: 05/08/2012] [Indexed: 05/22/2023]
Abstract
Pattern recognition receptors (PRRs) enable plants to sense non-self molecules displayed by microbes to mount proper defense responses or establish symbiosis. In recent years the importance of PRR subcellular trafficking to plant immunity has become apparent. PRRs traffic through the endoplasmatic reticulum (ER) and the Golgi apparatus to the plasma membrane, where they recognize their cognate ligands. At the plasma membrane, PRRs can be recycled or internalized via endocytic pathways. By using genetic and biochemical tools in combination with bioimaging, the trafficking pathways and their role in PRR perception of microbial molecules are now being revealed.
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Affiliation(s)
- Martina Beck
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
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40
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Robinson DG, Pimpl P, Scheuring D, Stierhof YD, Sturm S, Viotti C. Trying to make sense of retromer. TRENDS IN PLANT SCIENCE 2012; 17:431-9. [PMID: 22502774 DOI: 10.1016/j.tplants.2012.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/13/2012] [Accepted: 03/15/2012] [Indexed: 05/08/2023]
Abstract
Retromer is a cytosolic protein complex which binds to post-Golgi organelles involved in the trafficking of proteins to the lytic compartment of the cell. In non-plant organisms, retromer mediates the recycling of acid hydrolase receptors from early endosomal (EE) compartments. In plants, retromer components are required for the targeting of vacuolar storage proteins, and for the recycling of endocytosed PIN proteins. However, there are contradictory reports as to the localization of the sorting nexins and the core subunit of retromer. There is also uncertainty as to the identity of the organelles from which vacuolar sorting receptors (VSRs) and endocytosed plasma membrane (PM) proteins are recycled. In this review we try to resolve some of these conflicting observations.
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Affiliation(s)
- David G Robinson
- Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, D-69120 Heidelberg, Germany.
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41
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Law AHY, Chow CM, Jiang L. Secretory carrier membrane proteins. PROTOPLASMA 2012; 249:269-83. [PMID: 21633931 DOI: 10.1007/s00709-011-0295-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Accepted: 05/22/2011] [Indexed: 05/24/2023]
Abstract
Secretory carrier membrane proteins (SCAMPs) are a family of integral membrane proteins that play roles in mediating exocytosis in animal cells. However, relatively little is known about the subcellular localization, trafficking, and function of SCAMPs in plants. Several recent studies in plant cells indicate that plant SCAMPs share many similarities with their mammalian homologs although there are differences. In this review, we will first summarize and compare animal and plant SCAMPs in terms of their subcellular localization, trafficking, and possible functions. We will then present a phylogenetic analysis of plant and animal SCAMPs. Finally, we will present expression analysis on selective Arabidopsis SCAMPs in the hope of pointing to directions for functional characterization of plant SCAMPs in the future.
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Affiliation(s)
- Angus Ho Yin Law
- School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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Luu DT, Martinière A, Sorieul M, Runions J, Maurel C. Fluorescence recovery after photobleaching reveals high cycling dynamics of plasma membrane aquaporins in Arabidopsis roots under salt stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 69:894-905. [PMID: 22050464 DOI: 10.1111/j.1365-313x.2011.04841.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The constitutive cycling of plant plasma membrane (PM) proteins is an essential component of their function and regulation under resting or stress conditions. Transgenic Arabidopsis plants that express GFP fusions with AtPIP1;2 and AtPIP2;1, two prototypic PM aquaporins, were used to develop a fluorescence recovery after photobleaching (FRAP) approach. This technique was used to discriminate between PM and endosomal pools of the aquaporin constructs, and to estimate their cycling between intracellular compartments and the cell surface. The membrane trafficking inhibitors tyrphostin A23, naphthalene-1-acetic acid and brefeldin A blocked the latter process. By contrast, a salt treatment (100 mm NaCl for 30 min) markedly enhanced the cycling of the aquaporin constructs and modified their pharmacological inhibition profile. Two distinct models for PM aquaporin cycling in resting or salt-stressed root cells are discussed.
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Affiliation(s)
- Doan-Trung Luu
- Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier 2, Montpellier Cedex 2, France.
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43
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Novel N-benzoyl-2-hydroxybenzamide disrupts unique parasite secretory pathway. Antimicrob Agents Chemother 2012; 56:2666-82. [PMID: 22354304 DOI: 10.1128/aac.06450-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Toxoplasma gondii is a protozoan parasite that can damage the human brain and eyes. There are no curative medicines. Herein, we describe our discovery of N-benzoyl-2-hydroxybenzamides as a class of compounds effective in the low nanomolar range against T. gondii in vitro and in vivo. Our lead compound, QQ-437, displays robust activity against the parasite and could be useful as a new scaffold for development of novel and improved inhibitors of T. gondii. Our genome-wide investigations reveal a specific mechanism of resistance to N-benzoyl-2-hydroxybenzamides mediated by adaptin-3β, a large protein from the secretory protein complex. N-Benzoyl-2-hydroxybenzamide-resistant clones have alterations of their secretory pathway, which traffics proteins to micronemes, rhoptries, dense granules, and acidocalcisomes/plant-like vacuole (PLVs). N-Benzoyl-2-hydroxybenzamide treatment also alters micronemes, rhoptries, the contents of dense granules, and, most markedly, acidocalcisomes/PLVs. Furthermore, QQ-437 is active against chloroquine-resistant Plasmodium falciparum. Our studies reveal a novel class of compounds that disrupts a unique secretory pathway of T. gondii, with the potential to be used as scaffolds in the search for improved compounds to treat the devastating diseases caused by apicomplexan parasites.
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Chen X, Irani NG, Friml J. Clathrin-mediated endocytosis: the gateway into plant cells. CURRENT OPINION IN PLANT BIOLOGY 2011; 14:674-82. [PMID: 21945181 DOI: 10.1016/j.pbi.2011.08.006] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 08/22/2011] [Accepted: 08/31/2011] [Indexed: 05/18/2023]
Abstract
Endocytosis in plants has an essential role not only for basic cellular functions but also for growth and development, hormonal signaling and communication with the environment including nutrient delivery, toxin avoidance, and pathogen defense. The major endocytic mechanism in plants depends on the coat protein clathrin. It starts by clathrin-coated vesicle formation at the plasma membrane, where specific cargoes are recognized and packaged for internalization. Recently, genetic, biochemical and advanced microscopy studies provided initial insights into mechanisms and roles of clathrin-mediated endocytosis in plants. Here we summarize the present state of knowledge and compare mechanisms of clathrin-mediated endocytosis in plants with animal and yeast paradigms as well as review plant-specific regulations and roles of this process.
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Affiliation(s)
- Xu Chen
- Department of Plant Systems Biology, VIB, Technologiepark, Gent, Belgium
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Lee HY, Bowen CH, Popescu GV, Kang HG, Kato N, Ma S, Dinesh-Kumar S, Snyder M, Popescu SC. Arabidopsis RTNLB1 and RTNLB2 Reticulon-like proteins regulate intracellular trafficking and activity of the FLS2 immune receptor. THE PLANT CELL 2011; 23:3374-91. [PMID: 21949153 PMCID: PMC3203430 DOI: 10.1105/tpc.111.089656] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 08/26/2011] [Accepted: 09/12/2011] [Indexed: 05/18/2023]
Abstract
Receptors localized at the plasma membrane are critical for the recognition of pathogens. The molecular determinants that regulate receptor transport to the plasma membrane are poorly understood. In a screen for proteins that interact with the FLAGELIN-SENSITIVE2 (FLS2) receptor using Arabidopsis thaliana protein microarrays, we identified the reticulon-like protein RTNLB1. We showed that FLS2 interacts in vivo with both RTNLB1 and its homolog RTNLB2 and that a Ser-rich region in the N-terminal tail of RTNLB1 is critical for the interaction with FLS2. Transgenic plants that lack RTNLB1 and RTNLB2 (rtnlb1 rtnlb2) or overexpress RTNLB1 (RTNLB1ox) exhibit reduced activation of FLS2-dependent signaling and increased susceptibility to pathogens. In both rtnlb1 rtnlb2 and RTNLB1ox, FLS2 accumulation at the plasma membrane was significantly affected compared with the wild type. Transient overexpression of RTNLB1 led to FLS2 retention in the endoplasmic reticulum (ER) and affected FLS2 glycosylation but not FLS2 stability. Removal of the critical N-terminal Ser-rich region or either of the two Tyr-dependent sorting motifs from RTNLB1 causes partial reversion of the negative effects of excess RTNLB1 on FLS2 transport out of the ER and accumulation at the membrane. The results are consistent with a model whereby RTNLB1 and RTNLB2 regulate the transport of newly synthesized FLS2 to the plasma membrane.
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Affiliation(s)
- Hyoung Yool Lee
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853
| | | | - George Viorel Popescu
- National Institute for Laser, Plasma, and Radiation Physics, Magurele 077125 Bucharest, Romania
| | - Hong-Gu Kang
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853
| | - Naohiro Kato
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Shisong Ma
- College of Biological Sciences, University of California, Davis, California 95616
| | | | - Michael Snyder
- Department of Genetics, Stanford University, Stanford, California 94305
| | - Sorina Claudia Popescu
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853
- Address correspondence to
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Rae AL, Casu RE, Perroux JM, Jackson MA, Grof CPL. A soluble acid invertase is directed to the vacuole by a signal anchor mechanism. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:983-9. [PMID: 21156329 DOI: 10.1016/j.jplph.2010.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 11/18/2010] [Accepted: 11/18/2010] [Indexed: 05/07/2023]
Abstract
Enzyme activities in the vacuole have an important impact on the net concentration of sucrose. In sugarcane (Saccharum hybrid), immunolabelling demonstrated that a soluble acid invertase (β-fructofuranosidase; EC 3.2.1.26) is present in the vacuole of storage parenchyma cells during sucrose accumulation. Examination of sequences from sugarcane, barley and rice showed that the N-terminus of the invertase sequence contains a signal anchor and a tyrosine motif, characteristic of single-pass membrane proteins destined for lysosomal compartments. The N-terminal peptide from the barley invertase was shown to be capable of directing the green fluorescent protein to the vacuole in sugarcane cells. The results suggest that soluble acid invertase is sorted to the vacuole in a membrane-bound form.
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Affiliation(s)
- Anne L Rae
- CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, St. Lucia, Queensland 4067, Australia.
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Kim SJ, Bassham DC. TNO1 is involved in salt tolerance and vacuolar trafficking in Arabidopsis. PLANT PHYSIOLOGY 2011; 156:514-26. [PMID: 21521696 PMCID: PMC3177255 DOI: 10.1104/pp.110.168963] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 04/26/2011] [Indexed: 05/19/2023]
Abstract
The Arabidopsis (Arabidopsis thaliana) soluble N-ethylmaleimide-sensitive factor attachment protein receptor SYP41 is involved in vesicle fusion at the trans-Golgi network (TGN) and interacts with AtVPS45, SYP61, and VTI12. These proteins are involved in diverse cellular processes, including vacuole biogenesis and stress tolerance. A previously uncharacterized protein, named TNO1 (for TGN-localized SYP41-interacting protein), was identified by coimmunoprecipitation as a SYP41-interacting protein. TNO1 was found to localize to the TGN by immunofluorescence microscopy. A tno1 mutant showed increased sensitivity to high concentrations of NaCl, KCl, and LiCl and also to mannitol-induced osmotic stress. Localization of SYP61, which is involved in the salt stress response, was disrupted in the tno1 mutant. Vacuolar proteins were partially secreted to the apoplast in the tno1 mutant, suggesting that TNO1 is required for efficient protein trafficking to the vacuole. The tno1 mutant had delayed formation of the brefeldin A (BFA) compartment in cotyledons upon application of BFA, suggesting less efficient membrane fusion processes in the mutant. Unlike most TGN proteins, TNO1 does not relocate to the BFA compartment upon BFA treatment. These data demonstrate that TNO1 is involved in vacuolar trafficking and salt tolerance, potentially via roles in vesicle fusion and in maintaining TGN structure or identity.
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Affiliation(s)
| | - Diane C. Bassham
- Department of Genetics, Development, and Cell Biology (S.-J.K., D.C.B.), Plant Sciences Institute (D.C.B.), and Interdepartmental Genetics Program (S.-J.K., D.C.B.), Iowa State University, Ames, Iowa 50011
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Park M, Jürgens G. Membrane traffic and fusion at post-Golgi compartments. FRONTIERS IN PLANT SCIENCE 2011; 2:111. [PMID: 22645561 PMCID: PMC3355779 DOI: 10.3389/fpls.2011.00111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 12/19/2011] [Indexed: 05/18/2023]
Abstract
Complete sequencing of the Arabidopsis genome a decade ago has facilitated the functional analysis of various biological processes including membrane traffic by which many proteins are delivered to their sites of action and turnover. In particular, membrane traffic between post-Golgi compartments plays an important role in cell signaling, taking care of receptor-ligand interaction and inactivation, which requires secretion, endocytosis, and recycling or targeting to the vacuole for degradation. Here, we discuss recent studies that address the identity of post-Golgi compartments, the machinery involved in traffic and fusion or functionally characterized cargo proteins that are delivered to or pass through post-Golgi compartments. We also provide an outlook on future challenges in this area of research.
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Affiliation(s)
- Misoon Park
- Entwicklungsgenetik, Zentrum für Molekularbiologie der Pflanzen, University of TübingenTübingen, Germany
| | - Gerd Jürgens
- Entwicklungsgenetik, Zentrum für Molekularbiologie der Pflanzen, University of TübingenTübingen, Germany
- *Correspondence: Gerd Jürgens, Entwicklungsgenetik, Zentrum für Molekularbiologie der Pflanzen, University of Tübingen, Auf der Morgenstelle 3, 72076 Tübingen, Germany. e-mail:
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Foresti O, Gershlick DC, Bottanelli F, Hummel E, Hawes C, Denecke J. A recycling-defective vacuolar sorting receptor reveals an intermediate compartment situated between prevacuoles and vacuoles in tobacco. THE PLANT CELL 2010; 22:3992-4008. [PMID: 21177482 PMCID: PMC3027165 DOI: 10.1105/tpc.110.078436] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 10/04/2010] [Accepted: 11/11/2010] [Indexed: 05/18/2023]
Abstract
Plant vacuolar sorting receptors (VSRs) display cytosolic Tyr motifs (YMPL) for clathrin-mediated anterograde transport to the prevacuolar compartment. Here, we show that the same motif is also required for VSR recycling. A Y612A point mutation in Arabidopsis thaliana VSR2 leads to a quantitative shift in VSR2 steady state levels from the prevacuolar compartment to the trans-Golgi network when expressed in Nicotiana tabacum. By contrast, the L615A mutant VSR2 leaks strongly to vacuoles and accumulates in a previously undiscovered compartment. The latter is shown to be distinct from the Golgi stacks, the trans-Golgi network, and the prevacuolar compartment but is characterized by high concentrations of soluble vacuolar cargo and the rab5 GTPase Rha1(RabF2a). The results suggest that the prevacuolar compartment matures by gradual receptor depletion, leading to the formation of a late prevacuolar compartment situated between the prevacuolar compartment and the vacuole.
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Affiliation(s)
- Ombretta Foresti
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - David C. Gershlick
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Francesca Bottanelli
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Eric Hummel
- School of Life Sciences, Oxford Brookes, Oxford OX3 0BP, United Kingdom
| | - Chris Hawes
- School of Life Sciences, Oxford Brookes, Oxford OX3 0BP, United Kingdom
| | - Jürgen Denecke
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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