151
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Wang S, Ito T, Uehara M, Naito S, Takano J. UDP-D-galactose synthesis by UDP-glucose 4-epimerase 4 is required for organization of the trans-Golgi network/early endosome in Arabidopsis thaliana root epidermal cells. J Plant Res 2015; 128:863-873. [PMID: 26013532 DOI: 10.1007/s10265-015-0737-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 05/07/2015] [Indexed: 06/04/2023]
Abstract
Endomembrane organization is essential for cell physiology. We previously identified an Arabidopsis thaliana mutant in which a plasma membrane (PM) marker GFP-NIP5;1 and trans-Golgi network/early endosome (TGN/EE) markers were accumulated in intracellular aggregates in epidermal cells of the root elongation zone. The mutant was identified as an allele of UDP-glucose epimerase 4 (UGE4)/root hair defective 1/root epidermal bulgar 1, which was previously described as a mutant with swollen root epidermal cells and has an altered sugar composition in cell wall polysaccharides. Importantly, these defects including aggregate formation were restored by supplementation of D-galactose in the medium. These results suggested that UDP-D-galactose synthesis by UGE4 is important for endomembrane organization in addition to cell wall structure. Here, we further investigated the nature of the aggregates using various markers of endomembrane compartments and BOR1-GFP, which traffics from PM to vacuole in response to high-B supply. The markers of multi-vesicular bodies/late endosomes (MVB/LEs) and BOR1-GFP were strongly accumulated in the intracellular aggregates, while those of the endoplasmic reticulum (ER), the vacuolar membrane, and the Golgi were only slightly affected in the uge4 mutant. The abnormal localizations of these markers in the uge4 mutant differed from the effects of inhibitors of actin and microtubule polymerization, although they also affected endomembrane organization. Furthermore, electron microscopy analysis revealed accumulation of abnormal high-electron-density vesicles in elongating epidermal cells. The abnormal vesicles were often associated or interconnected with TGN/EEs and contained ADP-ribosylation factor 1, which is usually localized to the Golgi and the TGN/EEs. On the other hand, structures of the ER, Golgi apparatus, and MVB/LEs were apparently normal in uge4 cells. Together, our data indicate the importance of UDP-D-galactose synthesis by UGE4 for the organization and function of endomembranes, especially TGN/EEs, which are a sorting station of the secretory and vacuolar pathways.
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Affiliation(s)
- Sheliang Wang
- Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
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152
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Abstract
The movement of mature VLDL particles from the TGN to the plasma membrane (PM) is a complex physiological process that plays a critical role in hepatic lipid homeostasis. However, the molecular mechanisms regulating these intracellular transport events had not been studied until recently because of the lack of appropriate molecular assays and techniques. This unit provides a detailed description of cell-free approaches and techniques to study the TGN-to-PM transport of the mature VLDL at the molecular level. A major emphasis is placed on the preparation and purification of sub-cellular organelles because the success of in vitro assays for the vesicle formation and fusion depends on the quality of the isolated TGN, hepatic PM and hepatic cytosol. A number of critical factors that control the formation of mature VLDL-containing vesicle, the PG-VTV, from the TGN and their subsequent targeting to and fusion with the hepatic PM have been discussed.
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Affiliation(s)
- Shadab A Siddiqi
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida
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153
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Serth K, Schuster-Gossler K, Kremmer E, Hansen B, Marohn-Köhn B, Gossler A. O-fucosylation of DLL3 is required for its function during somitogenesis. PLoS One 2015; 10:e0123776. [PMID: 25856312 PMCID: PMC4391858 DOI: 10.1371/journal.pone.0123776] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 02/08/2015] [Indexed: 12/24/2022] Open
Abstract
Delta-like 3 (DLL3) is a member of the DSL family of Notch ligands in amniotes. In contrast to DLL1 and DLL4, the other Delta-like proteins in the mouse, DLL3 does not bind in trans to Notch and does not activate the receptor, but shows cis-interaction and cis-inhibitory properties on Notch signaling in vitro. Loss of the DSL protein DLL3 in the mouse results in severe somite patterning defects, which are virtually indistinguishable from the defects in mice that lack lunatic fringe (LFNG), a glycosyltransferase involved in modifying Notch signaling. Like LFNG, DLL3 is located within the trans-Golgi, however, its biochemical function is still unclear. Here, we show that i) both proteins interact, ii) epidermal growth factor like repeats 2 and 5 of DLL3 are O-fucosylated at consensus sites for POFUT1, and iii) further modified by FNG proteins in vitro. Embryos double homozygous for null mutations in Dll3 and Lfng are phenotypically indistinguishable from the single mutants supporting a potential common function. Mutation of the O-fucosylation sites in DLL3 does not disrupt the interaction of DLL3 with LFNG or full length Notch1or DLL1, and O-fucosylation-deficient DLL3 can still inhibit Notch in cis in vitro. However, in contrast to wild type DLL3, O-fucosylation-deficient DLL3 cannot compensate for the loss of endogenous DLL3 during somitogenesis in the embryo. Together our results suggest that the cis-inhibitory activity of DLL3 observed in cultured cells might not fully reflect its assumed essential physiological property, suggest that DLL3 and LFNG act together, and strongly supports that modification of DLL3 by O-linked fucose is essential for its function during somitogenesis.
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Affiliation(s)
- Katrin Serth
- Institut für Molekularbiologie OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, 30625, Hannover, Germany
| | - Karin Schuster-Gossler
- Institut für Molekularbiologie OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, 30625, Hannover, Germany
| | - Elisabeth Kremmer
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Molecular Immunology, Marchioninistrasse 25, 81377, Munich, Germany
| | - Birte Hansen
- Institut für Molekularbiologie OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, 30625, Hannover, Germany
| | - Britta Marohn-Köhn
- Institut für Molekularbiologie OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, 30625, Hannover, Germany
| | - Achim Gossler
- Institut für Molekularbiologie OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, 30625, Hannover, Germany
- * E-mail:
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154
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Reguera M, Bassil E, Tajima H, Wimmer M, Chanoca A, Otegui MS, Paris N, Blumwald E. pH Regulation by NHX-Type Antiporters Is Required for Receptor-Mediated Protein Trafficking to the Vacuole in Arabidopsis. Plant Cell 2015; 27:1200-17. [PMID: 25829439 PMCID: PMC4558692 DOI: 10.1105/tpc.114.135699] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/26/2015] [Accepted: 03/12/2015] [Indexed: 05/18/2023]
Abstract
Protein trafficking requires proper ion and pH homeostasis of the endomembrane system. The NHX-type Na(+)/H(+) antiporters NHX5 and NHX6 localize to the Golgi, trans-Golgi network, and prevacuolar compartments and are required for growth and trafficking to the vacuole. In the nhx5 nhx6 T-DNA insertional knockouts, the precursors of the 2S albumin and 12S globulin storage proteins accumulated and were missorted to the apoplast. Immunoelectron microscopy revealed the presence of vesicle clusters containing storage protein precursors and vacuolar sorting receptors (VSRs). Isolation and identification of complexes of VSRs with unprocessed 12S globulin by 2D blue-native PAGE/SDS-PAGE indicated that the nhx5 nhx6 knockouts showed compromised receptor-cargo association. In vivo interaction studies using bimolecular fluorescence complementation between VSR2;1, aleurain, and 12S globulin suggested that nhx5 nhx6 knockouts showed a significant reduction of VSR binding to both cargoes. In vivo pH measurements indicated that the lumens of VSR compartments containing aleurain, as well as the trans-Golgi network and prevacuolar compartments, were significantly more acidic in nhx5 nhx6 knockouts. This work demonstrates the importance of NHX5 and NHX6 in maintaining endomembrane luminal pH and supports the notion that proper vacuolar trafficking and proteolytic processing of storage proteins require endomembrane pH homeostasis.
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Affiliation(s)
- Maria Reguera
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Elias Bassil
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Hiromi Tajima
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Monika Wimmer
- Institute of Crop Science and Resource Conservation, Division of Plant Nutrition, University of Bonn, D-53115 Bonn, Germany
| | - Alexandra Chanoca
- Departments of Botany and Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Marisa S Otegui
- Departments of Botany and Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Nadine Paris
- Biochemistry and Plant Molecular Biology Laboratory, Unité Mixte de Recherche 5004, 34060 Montpellier, France
| | - Eduardo Blumwald
- Department of Plant Sciences, University of California, Davis, California 95616
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155
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Abstract
The small GTPase Arf-like protein 1 (Arl1) is well known for its role in intracellular vesicular transport at the trans-Golgi network (TGN). In this study, we used differential affinity chromatography combined with mass spectrometry to identify Arf-interacting protein 1b (arfaptin-1b) as an Arl1-interacting protein and characterized a novel function for arfaptin-1 (including the arfaptin-1a and 1b isoforms) in Arl1-mediated retrograde transport. Using a Shiga-toxin subunit B (STxB) transportation assay, we demonstrated that knockdown of arfaptin-1 accelerated the retrograde transport of STxB from the endosome to the Golgi apparatus, whereas Arl1 knockdown inhibited STxB transport compared with control cells. Arfaptin-1 overexpression, but not an Arl1 binding-defective mutant (arfaptin-1b-F317A), consistently inhibited STxB transport. Exogenous arfaptin-1 expression did not interfere with the localization of the Arl1-interacting proteins golgin-97 and golgin-245 to the TGN and vice versa. Moreover, we found that the N-terminal region of arfaptin-1 was involved in the regulation of retrograde transport. Our results show that arfaptin-1 acts as a negative regulator in Arl1-mediated retrograde transport and suggest that different functional complexes containing Arl1 form in distinct microdomains and are responsible for different functions.
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Affiliation(s)
- Lien-Hung Huang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - Wei-Chung Lee
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - Shu-Ting You
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chia-Chen Cheng
- Department of Cell and Molecular Biology, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - Chia-Jung Yu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
- Department of Cell and Molecular Biology, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
- Molecular Medicine Research Center, Chang Gung University, Tao-Yuan, Taiwan
- * E-mail:
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156
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von Schaewen A, Rips S, Jeong IS, Koiwa H. Arabidopsis thaliana KORRIGAN1 protein: N-glycan modification, localization, and function in cellulose biosynthesis and osmotic stress responses. Plant Signal Behav 2015; 10:e1024397. [PMID: 26039485 PMCID: PMC4622505 DOI: 10.1080/15592324.2015.1024397] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 02/25/2015] [Indexed: 05/18/2023]
Abstract
Plant cellulose biosynthesis is a complex process involving cellulose-synthase complexes (CSCs) and various auxiliary factors essential for proper orientation and crystallinity of cellulose microfibrils in the apoplast. Among them is KORRIGAN1 (KOR1), a type-II membrane protein with multiple N-glycans within its C-terminal cellulase domain. N-glycosylation of the cellulase domain was important for KOR1 targeting to and retention within the trans-Golgi network (TGN), and prevented accumulation of KOR1 at tonoplasts. The degree of successful TGN localization of KOR1 agreed well with in vivo-complementation efficacy of the rsw2-1 mutant, suggesting non-catalytic functions in the TGN. A dynamic interaction network involving microtubules, CSCs, KOR1, and currently unidentified glycoprotein component(s) likely determines stress-triggered re-organization of cellulose biosynthesis and resumption of cell-wall growth under stress.
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Affiliation(s)
- Antje von Schaewen
- Molekulare Physiologie der Pflanzen; Institut für Biologie & Biotechnologie der Pflanzen; Westfälische Wilhelms-Universität Münster; Münster, Germany
| | - Stephan Rips
- Molekulare Physiologie der Pflanzen; Institut für Biologie & Biotechnologie der Pflanzen; Westfälische Wilhelms-Universität Münster; Münster, Germany
| | - In Sil Jeong
- Vegetable and Fruit Improvement Center; Department of Horticultural Sciences; and Molecular and Environmental Plant Science Program; Texas A&M University; College Station, TX, USA
| | - Hisashi Koiwa
- Vegetable and Fruit Improvement Center; Department of Horticultural Sciences; and Molecular and Environmental Plant Science Program; Texas A&M University; College Station, TX, USA
- Correspondence to: Hisashi Koiwa;
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157
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Antignani V, Klocko AL, Bak G, Chandrasekaran SD, Dunivin T, Nielsen E. Recruitment of PLANT U-BOX13 and the PI4Kβ1/β2 phosphatidylinositol-4 kinases by the small GTPase RabA4B plays important roles during salicylic acid-mediated plant defense signaling in Arabidopsis. Plant Cell 2015; 27:243-61. [PMID: 25634989 PMCID: PMC4330583 DOI: 10.1105/tpc.114.134262] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 12/28/2014] [Accepted: 01/09/2015] [Indexed: 05/19/2023]
Abstract
Protection against microbial pathogens involves the activation of cellular immune responses in eukaryotes, and this cellular immunity likely involves changes in subcellular membrane trafficking. In eukaryotes, members of the Rab GTPase family of small monomeric regulatory GTPases play prominent roles in the regulation of membrane trafficking. We previously showed that RabA4B is recruited to vesicles that emerge from trans-Golgi network (TGN) compartments and regulates polarized membrane trafficking in plant cells. As part of this regulation, RabA4B recruits the closely related phosphatidylinositol 4-kinase (PI4K) PI4Kβ1 and PI4Kβ2 lipid kinases. Here, we identify a second Arabidopsis thaliana RabA4B-interacting protein, PLANT U-BOX13 (PUB13), which has recently been identified to play important roles in salicylic acid (SA)-mediated defense signaling. We show that PUB13 interacts with RabA4B through N-terminal domains and with phosphatidylinositol 4-phosphate (PI-4P) through a C-terminal armadillo domain. Furthermore, we demonstrate that a functional fluorescent PUB13 fusion protein (YFP-PUB13) localizes to TGN and Golgi compartments and that PUB13, PI4Kβ1, and PI4Kβ2 are negative regulators of SA-mediated induction of pathogenesis-related gene expression. Taken together, these results highlight a role for RabA4B and PI-4P in SA-dependent defense responses.
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Affiliation(s)
- Vincenzo Antignani
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Amy L Klocko
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Gwangbae Bak
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Suma D Chandrasekaran
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Taylor Dunivin
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Erik Nielsen
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
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158
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Penarete-Vargas DM, Boisson A, Urbach S, Chantelauze H, Peyrottes S, Fraisse L, Vial HJ. A chemical proteomics approach for the search of pharmacological targets of the antimalarial clinical candidate albitiazolium in Plasmodium falciparum using photocrosslinking and click chemistry. PLoS One 2014; 9:e113918. [PMID: 25470252 PMCID: PMC4254740 DOI: 10.1371/journal.pone.0113918] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 10/31/2014] [Indexed: 11/18/2022] Open
Abstract
Plasmodium falciparum is responsible for severe malaria which is one of the most prevalent and deadly infectious diseases in the world. The antimalarial therapeutic arsenal is hampered by the onset of resistance to all known pharmacological classes of compounds, so new drugs with novel mechanisms of action are critically needed. Albitiazolium is a clinical antimalarial candidate from a series of choline analogs designed to inhibit plasmodial phospholipid metabolism. Here we developed an original chemical proteomic approach to identify parasite proteins targeted by albitiazolium during their native interaction in living parasites. We designed a bifunctional albitiazolium-derived compound (photoactivable and clickable) to covalently crosslink drug-interacting parasite proteins in situ followed by their isolation via click chemistry reactions. Mass spectrometry analysis of drug-interacting proteins and subsequent clustering on gene ontology terms revealed parasite proteins involved in lipid metabolic activities and, interestingly, also in lipid binding, transport, and vesicular transport functions. In accordance with this, the albitiazolium-derivative was localized in the endoplasmic reticulum and trans-Golgi network of P. falciparum. Importantly, during competitive assays with albitiazolium, the binding of choline/ethanolamine phosphotransferase (the enzyme involved in the last step of phosphatidylcholine synthesis) was substantially displaced, thus confirming the efficiency of this strategy for searching albitiazolium targets.
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Affiliation(s)
- Diana Marcela Penarete-Vargas
- Dynamique des Interactions Membranaires Normales et Pathologiques, CNRS UMR 5235, Université Montpellier II, cc107, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
- * E-mail: (DMPV); (HJV)
| | - Anaïs Boisson
- Dynamique des Interactions Membranaires Normales et Pathologiques, CNRS UMR 5235, Université Montpellier II, cc107, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
| | - Serge Urbach
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, INSERM U661, Université Montpellier I, Université Montpellier II, F-34094 Montpellier, France
| | - Hervé Chantelauze
- Institut des Biomolécules Max Mousseron, CNRS UMR 5247, Université Montpellier II, cc1705, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
| | - Suzanne Peyrottes
- Institut des Biomolécules Max Mousseron, CNRS UMR 5247, Université Montpellier II, cc1705, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
| | - Laurent Fraisse
- Sanofi, Therapeutic Strategic Unit for Infectious Diseases, 195 route d’Espagne, BP 13669, 31036 Toulouse Cedex, France
| | - Henri J. Vial
- Dynamique des Interactions Membranaires Normales et Pathologiques, CNRS UMR 5235, Université Montpellier II, cc107, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
- * E-mail: (DMPV); (HJV)
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159
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Ivanov S, Harrison MJ. A set of fluorescent protein-based markers expressed from constitutive and arbuscular mycorrhiza-inducible promoters to label organelles, membranes and cytoskeletal elements in Medicago truncatula. Plant J 2014; 80:1151-63. [PMID: 25329881 DOI: 10.1111/tpj.12706] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 10/01/2014] [Accepted: 10/15/2014] [Indexed: 05/24/2023]
Abstract
Medicago truncatula is widely used for analyses of arbuscular mycorrhizal (AM) symbiosis and nodulation. To complement the genetic and genomic resources that exist for this species, we generated fluorescent protein fusions that label the nucleus, endoplasmic reticulum, Golgi apparatus, trans-Golgi network, plasma membrane, apoplast, late endosome/multivesicular bodies (MVB), transitory late endosome/ tonoplast, tonoplast, plastids, mitochondria, peroxisomes, autophagosomes, plasmodesmata, actin, microtubules, periarbuscular membrane (PAM) and periarbuscular apoplastic space (PAS) and expressed them from the constitutive AtUBQ10 promoter and the AM symbiosis-specific MtBCP1 promoter. All marker constructs showed the expected expression patterns and sub-cellular locations in M. truncatula root cells. As a demonstration of their utility, we used several markers to investigate AM symbiosis where root cells undergo major cellular alterations to accommodate their fungal endosymbiont. We demonstrate that changes in the position and size of the nuclei occur prior to hyphal entry into the cortical cells and do not require DELLA signaling. Changes in the cytoskeleton, tonoplast and plastids also occur in the colonized cells and in contrast to previous studies, we show that stromulated plastids are abundant in cells with developing and mature arbuscules, while lens-shaped plastids occur in cells with degenerating arbuscules. Arbuscule development and secretion of the PAM creates a periarbuscular apoplastic compartment which has been assumed to be continuous with apoplast of the cell. However, fluorescent markers secreted to the periarbuscular apoplast challenge this assumption. This marker resource will facilitate cell biology studies of AM symbiosis, as well as other aspects of legume biology.
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Affiliation(s)
- Sergey Ivanov
- Boyce Thompson Institute for Plant Research, Tower Road, Ithaca, NY, 14853, USA
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160
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Poulsen CP, Dilokpimol A, Mouille G, Burow M, Geshi N. Arabinogalactan glycosyltransferases target to a unique subcellular compartment that may function in unconventional secretion in plants. Traffic 2014; 15:1219-34. [PMID: 25074762 PMCID: PMC4285201 DOI: 10.1111/tra.12203] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 07/23/2014] [Accepted: 07/26/2014] [Indexed: 12/15/2022]
Abstract
We report that fluorescently tagged arabinogalactan glycosyltransferases target not only the Golgi apparatus but also uncharacterized smaller compartments when transiently expressed in Nicotiana benthamiana. Approximately 80% of AtGALT31A [Arabidopsis thaliana galactosyltransferase from family 31 (At1g32930)] was found in the small compartments, of which, 45 and 40% of AtGALT29A [Arabidopsis thaliana galactosyltransferase from family 29 (At1g08280)] and AtGlcAT14A [Arabidopsis thaliana glucuronosyltransferase from family 14 (At5g39990)] colocalized with AtGALT31A, respectively; in contrast, N-glycosylation enzymes rarely colocalized (3-18%), implicating a role of the small compartments in a part of arabinogalactan (O-glycan) biosynthesis rather than N-glycan processing. The dual localization of AtGALT31A was also observed for fluorescently tagged AtGALT31A stably expressed in an Arabidopsis atgalt31a mutant background. Further, site-directed mutagenesis of a phosphorylation site of AtGALT29A (Y144) increased the frequency of the protein being targeted to the AtGALT31A-localized small compartments, suggesting a role of Y144 in subcellular targeting. The AtGALT31A localized to the small compartments were colocalized with neither SYP61 (syntaxin of plants 61), a marker for trans-Golgi network (TGN), nor FM4-64-stained endosomes. However, 41% colocalized with EXO70E2 (Arabidopsis thaliana exocyst protein Exo70 homolog 2), a marker for exocyst-positive organelles, and least affected by Brefeldin A and Wortmannin. Taken together, AtGALT31A localized to small compartments that are distinct from the Golgi apparatus, the SYP61-localized TGN, FM4-64-stained endosomes and Wortmannin-vacuolated prevacuolar compartments, but may be part of an unconventional protein secretory pathway represented by EXO70E2 in plants.
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Affiliation(s)
- Christian Peter Poulsen
- Department of Plant and Environmental Sciences, Faculty of Science, University of CopenhagenThorvaldsensvej 40, Frederiksberg C, 1871, Denmark
| | - Adiphol Dilokpimol
- Department of Plant and Environmental Sciences, Faculty of Science, University of CopenhagenThorvaldsensvej 40, Frederiksberg C, 1871, Denmark
- Current address: Fungal Physiology, CBS-KNAW Fungal Biodiversity CenterUppsalalaan 8, Utrecht, 3584, CT, The Netherlands
| | - Grégory Mouille
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant SciencesVersailles, F-78026, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant SciencesVersailles, F-78026, France
| | - Meike Burow
- Department of Plant and Environmental Sciences, Faculty of Science, University of CopenhagenThorvaldsensvej 40, Frederiksberg C, 1871, Denmark
- Dynamo Center of Excellence, Faculty of Science, University of CopenhagenThorvaldsensvej 40, Frederiksberg C, 1871, Denmark
| | - Naomi Geshi
- Department of Plant and Environmental Sciences, Faculty of Science, University of CopenhagenThorvaldsensvej 40, Frederiksberg C, 1871, Denmark
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161
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Stephan O, Cottier S, Fahlén S, Montes-Rodriguez A, Sun J, Eklund DM, Klahre U, Kost B. RISAP is a TGN-associated RAC5 effector regulating membrane traffic during polar cell growth in tobacco. Plant Cell 2014; 26:4426-47. [PMID: 25387880 PMCID: PMC4277221 DOI: 10.1105/tpc.114.131078] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/26/2014] [Accepted: 10/15/2014] [Indexed: 05/08/2023]
Abstract
RAC/ROP GTPases coordinate actin dynamics and membrane traffic during polar plant cell expansion. In tobacco (Nicotiana tabacum), pollen tube tip growth is controlled by the RAC/ROP GTPase RAC5, which specifically accumulates at the apical plasma membrane. Here, we describe the functional characterization of RISAP, a RAC5 effector identified by yeast (Saccharomyces cerevisiae) two-hybrid screening. RISAP belongs to a family of putative myosin receptors containing a domain of unknown function 593 (DUF593) and binds via its DUF593 to the globular tail domain of a tobacco pollen tube myosin XI. It also interacts with F-actin and is associated with a subapical trans-Golgi network (TGN) compartment, whose cytoplasmic position at the pollen tube tip is maintained by the actin cytoskeleton. In this TGN compartment, apical secretion and endocytic membrane recycling pathways required for tip growth appear to converge. RISAP overexpression interferes with apical membrane traffic and blocks tip growth. RAC5 constitutively binds to the N terminus of RISAP and interacts in an activation-dependent manner with the C-terminal half of this protein. In pollen tubes, interaction between RAC5 and RISAP is detectable at the subapical TGN compartment. We present a model of RISAP regulation and function that integrates all these findings.
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Affiliation(s)
- Octavian Stephan
- Cell Biology and Erlangen Center of Plant Science (ECROPS), University of Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Stephanie Cottier
- Centre of Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Sara Fahlén
- Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
| | - Adriana Montes-Rodriguez
- Cell Biology and Erlangen Center of Plant Science (ECROPS), University of Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Jia Sun
- Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
| | - D Magnus Eklund
- Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
| | - Ulrich Klahre
- Centre of Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Benedikt Kost
- Cell Biology and Erlangen Center of Plant Science (ECROPS), University of Erlangen-Nuremberg, 91058 Erlangen, Germany
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162
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Serrano I, Gu Y, Qi D, Dubiella U, Innes RW. The Arabidopsis EDR1 protein kinase negatively regulates the ATL1 E3 ubiquitin ligase to suppress cell death. Plant Cell 2014; 26:4532-46. [PMID: 25398498 PMCID: PMC4277226 DOI: 10.1105/tpc.114.131540] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 10/18/2014] [Accepted: 10/27/2014] [Indexed: 05/19/2023]
Abstract
Loss-of-function mutations in the Arabidopsis thaliana ENHANCED DISEASE RESISTANCE1 (EDR1) gene confer enhanced programmed cell death under a variety of abiotic and biotic stress conditions. All edr1 mutant phenotypes can be suppressed by missense mutations in the KEEP ON GOING gene, which encodes a trans-Golgi network/early endosome (TGN/EE)-localized E3 ubiquitin ligase. Here, we report that EDR1 interacts with a second E3 ubiquitin ligase, ARABIDOPSIS TOXICOS EN LEVADURA1 (ATL1), and negatively regulates its activity. Overexpression of ATL1 in transgenic Arabidopsis induced severe growth inhibition and patches of cell death, while transient overexpression in Nicotiana benthamiana leaves induced cell death and tissue collapse. The E3 ligase activity of ATL1 was required for both of these processes. Importantly, we found that ATL1 interacts with EDR1 on TGN/EE vesicles and that EDR1 suppresses ATL1-mediated cell death in N. benthamiana and Arabidopsis. Lastly, knockdown of ATL1 expression suppressed cell death phenotypes associated with the edr1 mutant and made Arabidopsis hypersusceptible to powdery mildew infection. Taken together, our data indicate that ATL1 is a positive regulator of programmed cell death and EDR1 negatively regulates ATL1 activity at the TGN/EE and thus controls stress responses initiated by ATL1-mediated ubiquitination events.
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Affiliation(s)
- Irene Serrano
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Yangnan Gu
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Dong Qi
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Ullrich Dubiella
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Roger W Innes
- Department of Biology, Indiana University, Bloomington, Indiana 47405
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163
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Martínez-Martínez N, Martínez-Alonso E, Ballesta J, Martínez-Menárguez JA. Phospholipase D2 is involved in the formation of Golgi tubules and ArfGAP1 recruitment. PLoS One 2014; 9:e111685. [PMID: 25354038 PMCID: PMC4213061 DOI: 10.1371/journal.pone.0111685] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 10/03/2014] [Indexed: 11/19/2022] Open
Abstract
Lipids and lipid-modifying enzymes play a key role in the biogenesis, maintenance and fission of transport carriers in the secretory and endocytic pathways. In the present study we demonstrate that phosphatidic acid generated by phospholipase D2 (PLD2) is involved in the formation of Golgi tubules. The main evidence to support this is: 1) inhibitors of phosphatidic acid formation and PLD2 depletion inhibit the formation of tubules containing resident enzymes and regulators of intra-Golgi transport in a low temperature (15°C) model of Golgi tubulation but do not affect brefeldin A-induced tubules, 2) inhibition of PLD2 enzymatic activity and PLD2 depletion in cells cultured under physiological conditions (37°C) induce the formation of tubules specifically containing Golgi matrix proteins, and, 3) over-expression of PLD2 induces the formation of a tubular network. In addition, it was found that the generation of this lipid by the isoenzyme is necessary for ArfGAP1 recruitment to Golgi membranes. These results suggest that both proteins are involved in the molecular mechanisms which drive the formation of different types of Golgi tubules.
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Affiliation(s)
- Narcisa Martínez-Martínez
- Department of Cell Biology and Histology, Medical School, IMIB-Arrixaca, University of Murcia, Murcia, Spain
| | - Emma Martínez-Alonso
- Department of Cell Biology and Histology, Medical School, IMIB-Arrixaca, University of Murcia, Murcia, Spain
| | - José Ballesta
- Department of Cell Biology and Histology, Medical School, IMIB-Arrixaca, University of Murcia, Murcia, Spain
| | - José A. Martínez-Menárguez
- Department of Cell Biology and Histology, Medical School, IMIB-Arrixaca, University of Murcia, Murcia, Spain
- * E-mail:
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164
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Bashline L, Li S, Gu Y. The trafficking of the cellulose synthase complex in higher plants. Ann Bot 2014; 114:1059-67. [PMID: 24651373 PMCID: PMC4195546 DOI: 10.1093/aob/mcu040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 02/14/2014] [Indexed: 05/17/2023]
Abstract
BACKGROUND Cellulose is an important constituent of plant cell walls in a biological context, and is also a material commonly utilized by mankind in the pulp and paper, timber, textile and biofuel industries. The biosynthesis of cellulose in higher plants is a function of the cellulose synthase complex (CSC). The CSC, a large transmembrane complex containing multiple cellulose synthase proteins, is believed to be assembled in the Golgi apparatus, but is thought only to synthesize cellulose when it is localized at the plasma membrane, where CSCs synthesize and extrude cellulose directly into the plant cell wall. Therefore, the delivery and endocytosis of CSCs to and from the plasma membrane are important aspects for the regulation of cellulose biosynthesis. SCOPE Recent progress in the visualization of CSC dynamics in living plant cells has begun to reveal some of the routes and factors involved in CSC trafficking. This review highlights the most recent major findings related to CSC trafficking, provides novel perspectives on how CSC trafficking can influence the cell wall, and proposes potential avenues for future exploration.
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Affiliation(s)
- Logan Bashline
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Shundai Li
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Ying Gu
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
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165
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Wang X, Cai Y, Wang H, Zeng Y, Zhuang X, Li B, Jiang L. Trans-Golgi network-located AP1 gamma adaptins mediate dileucine motif-directed vacuolar targeting in Arabidopsis. Plant Cell 2014; 26:4102-18. [PMID: 25351491 PMCID: PMC4247576 DOI: 10.1105/tpc.114.129759] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/17/2014] [Accepted: 09/29/2014] [Indexed: 05/18/2023]
Abstract
Membrane proteins on the tonoplast are indispensible for vacuolar functions in plants. However, how these proteins are transported to the vacuole and how they become separated from plasma membrane proteins remain largely unknown. In this study, we used Arabidopsis thaliana vacuolar ion transporter1 (VIT1) as a reporter to study the mechanisms of tonoplast targeting. We showed that VIT1 reached the tonoplast through a pathway involving the endoplasmic reticulum (ER), Golgi, trans-Golgi network (TGN), prevacuolar compartment, and tonoplast. VIT1 contains a putative N-terminal dihydrophobic type ER export signal, and its N terminus has a conserved dileucine motif (EKQTLL), which is responsible for tonoplast targeting. In vitro peptide binding assays with synthetic VIT1 N terminus identified adaptor protein complex-1 (AP1) subunits that interacted with the dileucine motif. A deficiency of AP1 gamma adaptins in Arabidopsis cells caused relocation of tonoplast proteins containing the dileucine motif, such as VIT1 and inositol transporter1, to the plasma membrane. The dileucine motif also effectively rerouted the plasma membrane protein SCAMP1 to the tonoplast. Together with subcellular localization studies showing that AP1 gamma adaptins localize to the TGN, we propose that the AP1 complex on the TGN mediates tonoplast targeting of membrane proteins with the dileucine motif.
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Affiliation(s)
- Xiangfeng Wang
- 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
| | - Yi Cai
- 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
| | - Hao Wang
- 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
| | - Yonglun Zeng
- 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
| | - Xiaohong Zhuang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Baiying Li
- 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 CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China
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166
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Larson ER, Domozych DS, Tierney ML. SNARE VTI13 plays a unique role in endosomal trafficking pathways associated with the vacuole and is essential for cell wall organization and root hair growth in arabidopsis. Ann Bot 2014; 114:1147-59. [PMID: 24737717 PMCID: PMC4195547 DOI: 10.1093/aob/mcu041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
BACKGROUND AND AIMS Root hairs are responsible for water and nutrient uptake from the soil and their growth is responsive to biotic and abiotic changes in their environment. Root hair expansion is a polarized process requiring secretory and endosomal pathways that deliver and recycle plasma membrane and cell wall material to the growing root hair tip. In this paper, the role of VTI13 (AT3G29100), a member of the VTI vesicular soluble NSF attachment receptor (SNARE) gene family in Arabidopsis thaliana, in root hair growth is described. METHODS Genetic analysis and complementation of the vti13 root hair phenotypes of Arabidopsis thaliana were first used to assess the role of VTI13 in root hair growth. Transgenic lines expressing a green fluorescent protein (GFP)-VTI13 construct were used to characterize the intracellular localization of VTI13 in root hairs using confocal microscopy and immunotransmission electron microscopy. KEY RESULTS VTI13 was characterized and genetic analysis used to show that its function is required for root hair growth. Expression of a GFP-VTI13 fusion in the vti13 mutant background was shown to complement the vti13 root hair phenotype. GFP-VTI13 localized to both the vacuole membrane and a mobile endosomal compartment. The function of VTI13 was also required for the localization of SYP41 to the trans-Golgi network. Immunohistochemical analysis indicated that cell wall organization is altered in vti13 root hairs and root epidermal cells. CONCLUSIONS These results show that VTI13 plays a unique role in endosomal trafficking pathways associated with the vacuole within root hairs and is essential for the maintenance of cell wall organization and root hair growth in arabidopsis.
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Affiliation(s)
- Emily R Larson
- Cellular, Molecular and Biomedical Science Program Institute of Molecular Cell and Systems Biology, University of Glasgow College of Medical, Veterinary & Life Sciences, Glasgow G12 8QQ, UK
| | - David S Domozych
- Department of Biology, Skidmore College, Saratoga Springs, NY, USA
| | - Mary L Tierney
- Cellular, Molecular and Biomedical Science Program Department of Plant Biology, University of Vermont, Burlington, VT, USA
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167
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McDonold CM, Fromme JC. Four GTPases differentially regulate the Sec7 Arf-GEF to direct traffic at the trans-golgi network. Dev Cell 2014; 30:759-67. [PMID: 25220393 DOI: 10.1016/j.devcel.2014.07.016] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/06/2014] [Accepted: 07/07/2014] [Indexed: 11/16/2022]
Abstract
Traffic through the Golgi complex is controlled by small GTPases of the Arf and Rab families. Guanine nucleotide exchange factor (GEF) proteins activate these GTPases to control Golgi function, yet the full assortment of signals regulating these GEFs is unknown. The Golgi Arf-GEF Sec7 and the homologous BIG1/2 proteins are effectors of the Arf1 and Arl1 GTPases. We demonstrate that Sec7 is also an effector of two Rab GTPases, Ypt1 (Rab1) and Ypt31/32 (Rab11), signifying unprecedented signaling crosstalk between GTPase pathways. The molecular basis for the role of Ypt31/32 and Rab11 in vesicle formation has remained elusive. We find that Arf1, Arl1, and Ypt1 primarily affect the membrane localization of Sec7, whereas Ypt31/32 exerts a dramatic stimulatory effect on the nucleotide exchange activity of Sec7. The convergence of multiple signaling pathways on a master regulator reveals a mechanism for balancing incoming and outgoing traffic at the Golgi.
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Affiliation(s)
- Caitlin M McDonold
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - J Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
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168
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Rips S, Bentley N, Jeong IS, Welch JL, von Schaewen A, Koiwa H. Multiple N-glycans cooperate in the subcellular targeting and functioning of Arabidopsis KORRIGAN1. Plant Cell 2014; 26:3792-808. [PMID: 25238750 PMCID: PMC4213159 DOI: 10.1105/tpc.114.129718] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/14/2014] [Accepted: 09/09/2014] [Indexed: 05/18/2023]
Abstract
Arabidopsis thaliana KORRIGAN1 (KOR1) is an integral membrane endo-β1,4-glucanase in the trans-Golgi network and plasma membrane that is essential for cellulose biosynthesis. The extracellular domain of KOR1 contains eight N-glycosylation sites, N1 to N8, of which only N3 to N7 are highly conserved. Genetic evidence indicated that cellular defects in attachment and maturation of these N-glycans affect KOR1 function in vivo, whereas the manner by which N-glycans modulate KOR1 function remained obscure. Site-directed mutagenesis analysis of green fluorescent protein (GFP)-KOR1 expressed from its native regulatory sequences established that all eight N-glycosylation sites (N1 to N8) are used in the wild type, whereas stt3a-2 cells could only inefficiently add N-glycans to less conserved sites. GFP-KOR1 variants with a single N-glycan at nonconserved sites were less effective than those with one at a highly conserved site in rescuing the root growth phenotype of rsw2-1 (kor1 allele). When functionally compromised, GFP-KOR1 tended to accumulate at the tonoplast. GFP-KOR1Δall (without any N-glycan) exhibited partial complementation of rsw2-1; however, root growth of this line was still negatively affected by the absence of complex-type N-glycan modifications in the host plants. These results suggest that one or several additional factor(s) carrying complex N-glycans cooperate(s) with KOR1 in trans to grant proper targeting/functioning in plant cells.
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Affiliation(s)
- Stephan Rips
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Nolan Bentley
- Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Molecular and Environmental Plant Science Program, Texas A&M University, College Station, Texas 77843-2133
| | - In Sil Jeong
- Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Molecular and Environmental Plant Science Program, Texas A&M University, College Station, Texas 77843-2133
| | - Justin L Welch
- Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Molecular and Environmental Plant Science Program, Texas A&M University, College Station, Texas 77843-2133
| | - Antje von Schaewen
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Hisashi Koiwa
- Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Molecular and Environmental Plant Science Program, Texas A&M University, College Station, Texas 77843-2133
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169
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Korobko EV, Kiselev SL, Korobko IV. Characterization of Rabaptin-5 γ isoform. Biochemistry (Mosc) 2014; 79:856-64. [PMID: 25385014 DOI: 10.1134/s000629791409003x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Rab GTPases are key regulators of intracellular membrane traffic acting through their effector molecules. Rabaptin-5 is a Rab5 effector in early endosome fusion and connects Rab5- and Rab4-positive membrane compartments owing to its ability to interact with Rab4 GTPase. Recent studies showed that Rabaptin-5 transcript is subjected to extensive alternative splicing, thus resulting in expression of Rabaptin-5 isoforms mostly bearing short deletions in the polypeptide chain. As interactions of a Rab GTPase with different effectors lead to different responses, functional characterization of Rabaptin-5 isoforms becomes an attractive issue. Indeed, it was shown that Rab GTPase effector properties of Rabaptin-5 and its α and δ isoforms are different. This work focused on another Rabaptin-5 isoform, Rabaptin-5γ. Despite its ability to interact with Rab5, endogenously produced Rabaptin-5γ was absent from early endosomes. Rather, it was found to be tightly associated with trans-Golgi network and partially localized to a Rab4-positive membrane compartment. The revealed intracellular localization of Rabaptin-5γ indicates that it is not involved in Rab5-driven events; rather, it functions in other membrane transport steps. Our study signifies the role of alternative splicing in determination of functional activities of Rab effector molecules.
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Affiliation(s)
- E V Korobko
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
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170
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Toyooka K, Sato M, Kutsuna N, Higaki T, Sawaki F, Wakazaki M, Goto Y, Hasezawa S, Nagata N, Matsuoka K. Wide-range high-resolution transmission electron microscopy reveals morphological and distributional changes of endomembrane compartments during log to stationary transition of growth phase in tobacco BY-2 cells. Plant Cell Physiol 2014; 55:1544-55. [PMID: 24929423 DOI: 10.1093/pcp/pcu084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Rapid growth of plant cells by cell division and expansion requires an endomembrane trafficking system. The endomembrane compartments, such as the Golgi stacks, endosome and vesicles, are important in the synthesis and trafficking of cell wall materials during cell elongation. However, changes in the morphology, distribution and number of these compartments during the different stages of cell proliferation and differentiation have not yet been clarified. In this study, we examined these changes at the ultrastructural level in tobacco Bright yellow 2 (BY-2) cells during the log and stationary phases of growth. We analyzed images of the BY-2 cells prepared by the high-pressure freezing/freeze substitution technique with the aid of an auto-acquisition transmission electron microscope system. We quantified the distribution of secretory and endosomal compartments in longitudinal sections of whole cells by using wide-range gigapixel-class images obtained by merging thousands of transmission electron micrographs. During the log phase, all Golgi stacks were composed of several thick cisternae. Approximately 20 vesicle clusters (VCs), including the trans-Golgi network and secretory vesicle cluster, were observed throughout the cell. In the stationary-phase cells, Golgi stacks were thin with small cisternae, and only a few VCs were observed. Nearly the same number of multivesicular body and small high-density vesicles were observed in both the stationary and log phases. Results from electron microscopy and live fluorescence imaging indicate that the morphology and distribution of secretory-related compartments dramatically change when cells transition from log to stationary phases of growth.
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Affiliation(s)
- Kiminori Toyooka
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045 Japan
| | - Mayuko Sato
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045 Japan
| | - Natsumaro Kutsuna
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba, 277-8562 Japan
| | - Takumi Higaki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba, 277-8562 Japan
| | - Fumie Sawaki
- Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, 112-8681 Japan
| | - Mayumi Wakazaki
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045 Japan
| | - Yumi Goto
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045 Japan
| | - Seiichiro Hasezawa
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba, 277-8562 Japan
| | - Noriko Nagata
- Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, 112-8681 Japan
| | - Ken Matsuoka
- Laboratory of Plant Nutrition, Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka, 812-8581 Japan
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171
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Tafesse FG, Guimaraes CP, Maruyama T, Carette JE, Lory S, Brummelkamp TR, Ploegh HL. GPR107, a G-protein-coupled receptor essential for intoxication by Pseudomonas aeruginosa exotoxin A, localizes to the Golgi and is cleaved by furin. J Biol Chem 2014; 289:24005-18. [PMID: 25031321 PMCID: PMC4148833 DOI: 10.1074/jbc.m114.589275] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 07/08/2014] [Indexed: 12/25/2022] Open
Abstract
A number of toxins, including exotoxin A (PE) of Pseudomonas aeruginosa, kill cells by inhibiting protein synthesis. PE kills by ADP-ribosylation of the translation elongation factor 2, but many of the host factors required for entry, membrane translocation, and intracellular transport remain to be elucidated. A genome-wide genetic screen in human KBM7 cells was performed to uncover host factors used by PE, several of which were confirmed by CRISPR/Cas9-gene editing in a different cell type. Several proteins not previously implicated in the PE intoxication pathway were identified, including GPR107, an orphan G-protein-coupled receptor. GPR107 localizes to the trans-Golgi network and is essential for retrograde transport. It is cleaved by the endoprotease furin, and a disulfide bond connects the two cleaved fragments. Compromising this association affects the function of GPR107. The N-terminal region of GPR107 is critical for its biological function. GPR107 might be one of the long-sought receptors that associates with G-proteins to regulate intracellular vesicular transport.
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Affiliation(s)
- Fikadu G Tafesse
- From the Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142
| | - Carla P Guimaraes
- From the Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142
| | - Takeshi Maruyama
- From the Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142
| | - Jan E Carette
- the Stanford School of Medicine, Stanford, California 94305
| | - Stephen Lory
- the Harvard Medical School, Boston, Massachusetts 02115, and
| | - Thijn R Brummelkamp
- the Netherlands Cancer Institute, Postbus 90203, 1006 BE Amsterdam, The Netherlands
| | - Hidde L Ploegh
- From the Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142,
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172
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Naramoto S, Otegui MS, Kutsuna N, de Rycke R, Dainobu T, Karampelias M, Fujimoto M, Feraru E, Miki D, Fukuda H, Nakano A, Friml J. Insights into the localization and function of the membrane trafficking regulator GNOM ARF-GEF at the Golgi apparatus in Arabidopsis. Plant Cell 2014; 26:3062-76. [PMID: 25012191 PMCID: PMC4145132 DOI: 10.1105/tpc.114.125880] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 05/28/2014] [Accepted: 06/04/2014] [Indexed: 05/19/2023]
Abstract
GNOM is one of the most characterized membrane trafficking regulators in plants, with crucial roles in development. GNOM encodes an ARF-guanine nucleotide exchange factor (ARF-GEF) that activates small GTPases of the ARF (ADP ribosylation factor) class to mediate vesicle budding at endomembranes. The crucial role of GNOM in recycling of PIN auxin transporters and other proteins to the plasma membrane was identified in studies using the ARF-GEF inhibitor brefeldin A (BFA). GNOM, the most prominent regulator of recycling in plants, has been proposed to act and localize at so far elusive recycling endosomes. Here, we report the GNOM localization in context of its cellular function in Arabidopsis thaliana. State-of-the-art imaging, pharmacological interference, and ultrastructure analysis show that GNOM predominantly localizes to Golgi apparatus. Super-resolution confocal live imaging microscopy identified GNOM and its closest homolog GNOM-like 1 at distinct subdomains on Golgi cisternae. Short-term BFA treatment stabilizes GNOM at the Golgi apparatus, whereas prolonged exposures results in GNOM translocation to trans-Golgi network (TGN)/early endosomes (EEs). Malformed TGN/EE in gnom mutants suggests a role for GNOM in maintaining TGN/EE function. Our results redefine the subcellular action of GNOM and reevaluate the identity and function of recycling endosomes in plants.
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Affiliation(s)
- Satoshi Naramoto
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium Molecular Membrane Biology laboratory, RIKEN Advanced Science Institute, Wako, Saitama 351-0198, Japan Department of Life Science, International Christian University, Mitaka-shi, Tokyo 181-8585, Japan
| | - Marisa S Otegui
- Department of Botany and Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Natsumaro Kutsuna
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | - Riet de Rycke
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Tomoko Dainobu
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Michael Karampelias
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Masaru Fujimoto
- Laboratory of Plant Molecular Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Elena Feraru
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Daisuke Miki
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Hiroo Fukuda
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Akihiko Nakano
- Molecular Membrane Biology laboratory, RIKEN Advanced Science Institute, Wako, Saitama 351-0198, Japan Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan Live Cell Molecular Imaging Research Team, Extreme Photonics Research Group, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
| | - Jiří Friml
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
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173
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Wang S, Ma Z, Xu X, Wang Z, Sun L, Zhou Y, Lin X, Hong W, Wang T. A role of Rab29 in the integrity of the trans-Golgi network and retrograde trafficking of mannose-6-phosphate receptor. PLoS One 2014; 9:e96242. [PMID: 24788816 PMCID: PMC4008501 DOI: 10.1371/journal.pone.0096242] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 04/07/2014] [Indexed: 11/18/2022] Open
Abstract
Rab29 (also referred as Rab7L1) is a novel Rab protein, and is recently demonstrated to regulate phagocytosis and traffic from the Golgi to the lysosome. However, its roles in membrane trafficking have not been investigated extensively. Our results in this study revealed that Rab29 is associated with the trans-Golgi network (TGN), and is essential for maintaining the integrity of the TGN, because inhibition of the activity of Rab29 or depletion of Rab29 resulted in fragmentation of the TGN marked by TGN46. Expression of the dominant negative form Rab29T21N or shRNA-Rab29 also altered the distribution of mannose-6-phosphate receptor (M6PR), and interrupted the retrograde trafficking of M6PR through monitoring the endocytosis of CD8-tagged calcium dependent M6PR (cdM6PR) or calcium independent M6PR (ciM6PR), but without significant effects on the anterograde trafficking of vesicular stomatitis virus G protein (VSV-G). Our results suggest that Rab29 is essential for the integrity of the TGN and participates in the retrograde trafficking of M6PRs.
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Affiliation(s)
- Shicong Wang
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, Fujian, China
| | - Zexu Ma
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, Fujian, China
| | - Xiaohui Xu
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, Fujian, China
| | - Zhen Wang
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, Fujian, China
| | - Lixiang Sun
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, Fujian, China
| | - Yunhe Zhou
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, Fujian, China
| | - Xiaosi Lin
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, Fujian, China
| | - Wanjin Hong
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, Fujian, China
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Singapore, Singapore
| | - Tuanlao Wang
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, Fujian, China
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174
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Abstract
The retrograde trafficking from endosomes to the trans-Golgi network (TGN) is one of the major endocytic pathways to divert proteins and lipids away from lysosomal degradation. Retrograde transported cargos enter the TGN via two itineraries from either the early endosome/recycling endosome or the late endosome and involve various machinery components such as retromer, sorting nexins, clathrin, small GTPases, tethering factors and SNAREs. Recently, the pathway has been recognized for its role in signal transduction, physiology and pathogenesis of human diseases.
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Affiliation(s)
- Lei Lu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
| | - Wanjin Hong
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore; School of Pharmaceutical Sciences, Xiamen University, Xiamen, People's Republic of China
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175
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Shirakawa M, Ueda H, Koumoto Y, Fuji K, Nishiyama C, Kohchi T, Hara-Nishimura I, Shimada T. CONTINUOUS VASCULAR RING (COV1) is a trans-Golgi network-localized membrane protein required for Golgi morphology and vacuolar protein sorting. Plant Cell Physiol 2014; 55:764-72. [PMID: 24363287 DOI: 10.1093/pcp/pct195] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The trans-Golgi network (TGN) is a tubular-vesicular organelle that matures from the trans cisternae of the Golgi apparatus. In plants, the TGN functions as a central hub for three trafficking pathways: the secretory pathway, the vacuolar trafficking pathway and the endocytic pathway. Here, we describe a novel TGN-localized membrane protein, CONTINUOUS VASCULAR RING (COV1), that is crucial for TGN function in Arabidopsis. The COV1 gene was originally identified from the stem vascular patterning mutant of Arabidopsis thaliana. However, the molecular function of COV1 was not identified. Fluorescently tagged COV1 proteins co-localized with the TGN marker proteins, SYNTAXIN OF PLANTS 4 (SYP4) and vacuolar-type H(+)-ATPase subunit a1 (VHA-a1). Consistently, COV1-localized compartments were sensitive to concanamycin A, a specific inhibitor of VHA. Intriguingly, cov1 mutants exhibited abnormal Golgi morphologies, including a reduction in the number of Golgi cisternae and a reduced association between the TGN and the Golgi apparatus. A deficiency in COV1 also resulted in a defect in vacuolar protein sorting, which was characterized by the abnormal accumulation of storage protein precursors in seeds. Moreover, we found that the development of an idioblast, the myrosin cell, was abnormally increased in cov1 leaves. Our results demonstrate that the novel TGN-localized protein COV1 is required for Golgi morphology, vacuolar trafficking and myrosin cell development.
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Affiliation(s)
- Makoto Shirakawa
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
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176
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Ding WG, Xie Y, Toyoda F, Matsuura H. Improved functional expression of human cardiac kv1.5 channels and trafficking-defective mutants by low temperature treatment. PLoS One 2014; 9:e92923. [PMID: 24663680 PMCID: PMC3963980 DOI: 10.1371/journal.pone.0092923] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 02/26/2014] [Indexed: 11/18/2022] Open
Abstract
We herein investigated the effect of low temperature exposure on the expression, degradation, localization and activity of human Kv1.5 (hKv1.5). In hKv1.5-expressing CHO cells, the currents were significantly increased when cultured at a reduced temperature (28°C) compared to those observed at 37°C. Western blot analysis indicated that the protein levels (both immature and mature proteins) of hKv1.5 were significantly elevated under the hypothermic condition. Treatment with a proteasome inhibitor, MG132, significantly increased the immature, but not the mature, hKv1.5 protein at 37°C, however, there were no changes in either the immature or mature hKv1.5 proteins at low temperature following MG132 exposure. These observations suggest that the enhancement of the mature hKv1.5 protein at reduced temperature may not result from the inhibition of proteolysis. Moreover, the hKv1.5 fluorescence signal in the cells increased significantly on the cell surface at 28°C versus those cultured at 37°C. Importantly, the low temperature treatment markedly shifted the subcellular distribution of the mature hKv1.5, which showed considerable overlap with the trans-Golgi component. Experiments using tunicamycin, an inhibitor of N-glycosylation, indicated that the N-glycosylation of hKv1.5 is more effective at 28°C than at 37°C. Finally, the hypothermic treatment also rescued the protein expression and currents of trafficking-defective hKv1.5 mutants. These results indicate that low temperature exposure stabilizes the protein in the cellular organelles or on the plasma membrane, and modulates its maturation and trafficking, thus enhancing the currents of hKv1.5 and its trafficking defect mutants.
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Affiliation(s)
- Wei-Guang Ding
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
- * E-mail:
| | - Yu Xie
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Futoshi Toyoda
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Hiroshi Matsuura
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
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177
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Robinson DG, Pimpl P. Clathrin and post-Golgi trafficking: a very complicated issue. Trends Plant Sci 2014; 19:134-9. [PMID: 24263003 DOI: 10.1016/j.tplants.2013.10.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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178
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Fan X, Yang C, Klisch D, Ferguson A, Bhaellero RP, Niu X, Wilson ZA. ECHIDNA protein impacts on male fertility in Arabidopsis by mediating trans-Golgi network secretory trafficking during anther and pollen development. Plant Physiol 2014; 164:1338-49. [PMID: 24424320 PMCID: PMC3938624 DOI: 10.1104/pp.113.227769] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 01/14/2014] [Indexed: 05/18/2023]
Abstract
The trans-Golgi network (TGN) plays a central role in cellular secretion and has been implicated in sorting cargo destined for the plasma membrane. Previously, the Arabidopsis (Arabidopsis thaliana) echidna (ech) mutant was shown to exhibit a dwarf phenotype due to impaired cell expansion. However, ech also has a previously uncharacterized phenotype of reduced male fertility. This semisterility is due to decreased anther size and reduced amounts of pollen but also to decreased pollen viability, impaired anther opening, and pollen tube growth. An ECH translational fusion (ECHPro:ECH-yellow fluorescent protein) revealed developmentally regulated tissue-specific expression, with expression in the tapetum during early anther development and microspore release and subsequent expression in the pollen, pollen tube, and stylar tissues. Pollen viability and production, along with germination and pollen tube growth, were all impaired. The ech anther endothecium secondary wall thickening also appeared reduced and disorganized, resulting in incomplete anther opening. This did not appear to be due to anther secondary thickening regulatory genes but perhaps to altered secretion of wall materials through the TGN as a consequence of the absence of the ECH protein. ECH expression is critical for a variety of aspects of male reproduction, including the production of functional pollen grains, their effective release, germination, and tube formation. These stages of pollen development are fundamentally influenced by TGN trafficking of hormones and wall components. Overall, this suggests that the fertility defect is multifaceted, with the TGN trafficking playing a significant role in the process of both pollen formation and subsequent fertilization.
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179
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McFarlane HE, Watanabe Y, Yang W, Huang Y, Ohlrogge J, Samuels AL. Golgi- and trans-Golgi network-mediated vesicle trafficking is required for wax secretion from epidermal cells. Plant Physiol 2014; 164:1250-60. [PMID: 24468625 PMCID: PMC3938617 DOI: 10.1104/pp.113.234583] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 01/16/2014] [Indexed: 05/18/2023]
Abstract
Lipid secretion from epidermal cells to the plant surface is essential to create the protective plant cuticle. Cuticular waxes are unusual secretory products, consisting of a variety of highly hydrophobic compounds including saturated very-long-chain alkanes, ketones, and alcohols. These compounds are synthesized in the endoplasmic reticulum (ER) but must be trafficked to the plasma membrane for export by ATP-binding cassette transporters. To test the hypothesis that wax components are trafficked via the endomembrane system and packaged in Golgi-derived secretory vesicles, Arabidopsis (Arabidopsis thaliana) stem wax secretion was assayed in a series of vesicle-trafficking mutants, including gnom like1-1 (gnl1-1), transport particle protein subunit120-4, and echidna (ech). Wax secretion was dependent upon GNL1 and ECH. Independent of secretion phenotypes, mutants with altered ER morphology also had decreased wax biosynthesis phenotypes, implying that the biosynthetic capacity of the ER is closely related to its structure. These results provide genetic evidence that wax export requires GNL1- and ECH-dependent endomembrane vesicle trafficking to deliver cargo to plasma membrane-localized ATP-binding cassette transporters.
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180
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Young E, Zheng ZY, Wilkins AD, Jeong HT, Li M, Lichtarge O, Chang EC. Regulation of Ras localization and cell transformation by evolutionarily conserved palmitoyltransferases. Mol Cell Biol 2014; 34:374-85. [PMID: 24248599 PMCID: PMC3911504 DOI: 10.1128/mcb.01248-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 10/16/2013] [Accepted: 11/09/2013] [Indexed: 01/06/2023] Open
Abstract
Ras can act on the plasma membrane (PM) to mediate extracellular signaling and tumorigenesis. To identify key components controlling Ras PM localization, we performed an unbiased screen to seek Schizosaccharomyces pombe mutants with reduced PM Ras. Five mutants were found with mutations affecting the same gene, S. pombe erf2 (sp-erf2), encoding sp-Erf2, a palmitoyltransferase, with various activities. sp-Erf2 localizes to the trans-Golgi compartment, a process which is mediated by its third transmembrane domain and the Erf4 cofactor. In fission yeast, the human ortholog zDHHC9 rescues the phenotypes of sp-erf2 null cells. In contrast, expressing zDHHC14, another sp-Erf2-like human protein, did not rescue Ras1 mislocalization in these cells. Importantly, ZDHHC9 is widely overexpressed in cancers. Overexpressing ZDHHC9 promotes, while repressing it diminishes, Ras PM localization and transformation of mammalian cells. These data strongly demonstrate that sp-Erf2/zDHHC9 palmitoylates Ras proteins in a highly selective manner in the trans-Golgi compartment to facilitate PM targeting via the trans-Golgi network, a role that is most certainly critical for Ras-driven tumorigenesis.
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Affiliation(s)
- Evelin Young
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Ze-Yi Zheng
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Angela D. Wilkins
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- CIBR Center for Computational and Integrative Biomedical Research, Baylor College of Medicine, Houston, Texas, USA
| | - Hee-Tae Jeong
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Min Li
- Department of Oncology, Nanjing Hospital of Traditional Chinese Medicine, Nanjing, Jiangsu, China
| | - Olivier Lichtarge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- CIBR Center for Computational and Integrative Biomedical Research, Baylor College of Medicine, Houston, Texas, USA
| | - Eric C. Chang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
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181
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Johns HL, Gonzalez-Lopez C, Sayers CL, Hollinshead M, Elliott G. Rab6 dependent post-Golgi trafficking of HSV1 envelope proteins to sites of virus envelopment. Traffic 2014; 15:157-78. [PMID: 24152084 PMCID: PMC4345966 DOI: 10.1111/tra.12134] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 10/17/2013] [Accepted: 10/23/2013] [Indexed: 12/19/2022]
Abstract
Herpes simplex virus 1 (HSV1) is an enveloped virus that uses undefined transport carriers for trafficking of its glycoproteins to envelopment sites. Screening of an siRNA library against 60 Rab GTPases revealed Rab6 as the principal Rab involved in HSV1 infection, with its depletion preventing Golgi-to-plasma membrane transport of HSV1 glycoproteins in a pathway used by several integral membrane proteins but not the luminal secreted protein Gaussia luciferase. Knockdown of Rab6 reduced virus yield to 1% and inhibited capsid envelopment, revealing glycoprotein exocytosis as a prerequisite for morphogenesis. Rab6-dependent virus production did not require the effectors myosin-II, bicaudal-D, dynactin-1 or rabkinesin-6, but was facilitated by ERC1, a factor involved in linking microtubules to the cell cortex. Tubulation and exocytosis of Rab6-positive, glycoprotein-containing membranes from the Golgi was substantially augmented by infection, resulting in enhanced and targeted delivery to cell tips. This reveals HSV1 morphogenesis as one of the first biological processes shown to be dependent on the exocytic activity of Rab6.
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Affiliation(s)
- Helen L Johns
- Section of Virology, Faculty of Medicine, Imperial College LondonLondon, W2 1PG, UK
| | | | - Charlotte L Sayers
- Section of Virology, Faculty of Medicine, Imperial College LondonLondon, W2 1PG, UK
| | - Michael Hollinshead
- Section of Virology, Faculty of Medicine, Imperial College LondonLondon, W2 1PG, UK
| | - Gillian Elliott
- Section of Virology, Faculty of Medicine, Imperial College LondonLondon, W2 1PG, UK
- Current address: Department of Microbial & Cellular Sciences, Faculty of Health & Medical Sciences, University of SurreyGuildford, GU2 7XH, UK
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182
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Abstract
A detailed understanding of endomembrane processes and their biological roles is vital for a complete picture of plant growth and development; however their highly dynamic nature has complicated comprehensive and rigorous studies so far. Recent pioneering efforts have demonstrated that isolation of vesicles in their native state, paired with a quantitative identification of their cargo, offers a viable and practicable approach for the dissection of endomembrane trafficking pathways. The protocol presented in this chapter describes in detail the isolation of the SYP61 trans-Golgi network vesicles from Arabidopsis. With minor alterations, in a few key parameters, it can be adopted to yield a universal procedure for the broad spectrum of plant vesicles.
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Affiliation(s)
- Eunsook Park
- Department of Plant sciences, University of California Davis, Asmundson Hall, One Shields Avenue, Davis, CA, 95616, USA
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183
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Knip M, Hiemstra S, Sietsma A, Castelein M, de Pater S, Hooykaas P. DAYSLEEPER: a nuclear and vesicular-localized protein that is expressed in proliferating tissues. BMC Plant Biol 2013; 13:211. [PMID: 24330683 PMCID: PMC4029315 DOI: 10.1186/1471-2229-13-211] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 11/27/2013] [Indexed: 05/08/2023]
Abstract
BACKGROUND DAYSLEEPER is a domesticated transposase that is essential for development in Arabidopsis thaliana [Nature, 436:282-284, 2005]. It is derived from a hAT-superfamily transposon and contains many of the features found in the coding sequence of these elements [Nature, 436:282-284, 2005, Genetics, 158:949-957, 2001]. This work sheds light on the expression of this gene and localization of its product in protoplasts and in planta. Using deletion constructs, important domains in the protein were identified. RESULTS DAYSLEEPER is predominantly expressed in meristems, developing flowers and siliques. The protein is mainly localized in the nucleus, but can also be seen in discrete foci in the cytoplasm. Using several vesicular markers, we found that these foci belong to vesicular structures of the trans-golgi network, multivesicular bodies (MVB's) and late endosomes. The central region as well as both the N- and the C-terminus are essential to DAYSLEEPER function, since versions of DAYSLEEPER deleted for these regions are not able to complement the daysleeper phenotype. Like hAT-transposases, we show that DAYSLEEPER has a functionally conserved dimerization domain [J Biol Chem, 282:7563-7575, 2007]. CONCLUSIONS DAYSLEEPER has retained the global structure of hAT transposases and it seems that most of these conserved features are essential to DAYSLEEPER's cellular function. Although structurally similar, DAYSLEEPER seems to have broadened its range of action beyond the nucleus in comparison to transposases.
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Affiliation(s)
- Marijn Knip
- Department of Molecular and Developmental Genetics, Institute of Biology, Leiden University, Sylviusweg 72, Leiden 2333 BE, The Netherlands
- Current address: Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C 1871, Denmark
| | - Steven Hiemstra
- Department of Molecular and Developmental Genetics, Institute of Biology, Leiden University, Sylviusweg 72, Leiden 2333 BE, The Netherlands
- Current address: Department of Toxicology, Leiden/Amsterdam Center for Drug Research, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Afke Sietsma
- Department of Molecular and Developmental Genetics, Institute of Biology, Leiden University, Sylviusweg 72, Leiden 2333 BE, The Netherlands
- Current address: Department of Ecology and Physiology of Plants, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1087, Amsterdam 1081 HV, The Netherlands
| | - Marina Castelein
- Department of Molecular and Developmental Genetics, Institute of Biology, Leiden University, Sylviusweg 72, Leiden 2333 BE, The Netherlands
| | - Sylvia de Pater
- Department of Molecular and Developmental Genetics, Institute of Biology, Leiden University, Sylviusweg 72, Leiden 2333 BE, The Netherlands
| | - Paul Hooykaas
- Department of Molecular and Developmental Genetics, Institute of Biology, Leiden University, Sylviusweg 72, Leiden 2333 BE, The Netherlands
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184
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Ishii Y, Nakahara T, Kataoka M, Kusumoto-Matsuo R, Mori S, Takeuchi T, Kukimoto I. Identification of TRAPPC8 as a host factor required for human papillomavirus cell entry. PLoS One 2013; 8:e80297. [PMID: 24244674 PMCID: PMC3828182 DOI: 10.1371/journal.pone.0080297] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 10/01/2013] [Indexed: 11/19/2022] Open
Abstract
Human papillomavirus (HPV) is a non-enveloped virus composed of a circular DNA genome and two capsid proteins, L1 and L2. Multiple interactions between its capsid proteins and host cellular proteins are required for infectious HPV entry, including cell attachment and internalization, intracellular trafficking and viral genome transfer into the nucleus. Using two variants of HPV type 51, the Ma and Nu strains, we have previously reported that MaL2 is required for efficient pseudovirus (PsV) transduction. However, the cellular factors that confer this L2 dependency have not yet been identified. Here we report that the transport protein particle complex subunit 8 (TRAPPC8) specifically interacts with MaL2. TRAPPC8 knockdown in HeLa cells yielded reduced levels of reporter gene expression when inoculated with HPV51Ma, HPV16, and HPV31 PsVs. TRAPPC8 knockdown in HaCaT cells also showed reduced susceptibility to infection with authentic HPV31 virions, indicating that TRAPPC8 plays a crucial role in native HPV infection. Immunofluorescence microscopy revealed that the central region of TRAPPC8 was exposed on the cell surface and colocalized with inoculated PsVs. The entry of Ma, Nu, and L2-lacking PsVs into cells was equally impaired in TRAPPC8 knockdown HeLa cells, suggesting that TRAPPC8-dependent endocytosis plays an important role in HPV entry that is independent of L2 interaction. Finally, expression of GFP-fused L2 that can also interact with TRAPPC8 induced dispersal of the Golgi stack structure in HeLa cells, a phenotype also observed by TRAPPC8 knockdown. These results suggest that during viral intracellular trafficking, binding of L2 to TRAPPC8 inhibits its function resulting in Golgi destabilization, a process that may assist HPV genome escape from the trans-Golgi network.
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Affiliation(s)
- Yoshiyuki Ishii
- Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tomomi Nakahara
- Virology Division, National Cancer Center Research Institute, Tokyo, Japan
| | - Michiyo Kataoka
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Rika Kusumoto-Matsuo
- Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Seiichiro Mori
- Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Takamasa Takeuchi
- Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Iwao Kukimoto
- Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
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185
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Kinouchi K, Ichihara A, Sano M, Sun-Wada GH, Wada Y, Ochi H, Fukuda T, Bokuda K, Kurosawa H, Yoshida N, Takeda S, Fukuda K, Itoh H. The role of individual domains and the significance of shedding of ATP6AP2/(pro)renin receptor in vacuolar H(+)-ATPase biogenesis. PLoS One 2013; 8:e78603. [PMID: 24223829 PMCID: PMC3817224 DOI: 10.1371/journal.pone.0078603] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 09/13/2013] [Indexed: 12/16/2022] Open
Abstract
The ATPase 6 accessory protein 2 (ATP6AP2)/(pro)renin receptor (PRR) is essential for the biogenesis of active vacuolar H+-ATPase (V-ATPase). Genetic deletion of ATP6AP2/PRR causes V-ATPase dysfunction and compromises vesicular acidification. Here, we characterized the domains of ATP6AP2/PRR involved in active V-ATPase biogenesis. Three forms of ATP6AP2/PRR were found intracellularly: full-length protein and the N- and C-terminal fragments of furin cleavage products, with the N-terminal fragment secreted extracellularly. Genetic deletion of ATP6AP2/PRR did not affect the protein stability of V-ATPase subunits. The extracellular domain (ECD) and transmembrane domain (TM) of ATP6AP2/PRR were indispensable for the biogenesis of active V-ATPase. A deletion mutant of ATP6AP2/PRR, which lacks exon 4-encoded amino acids inside the ECD (Δ4M) and causes X-linked mental retardation Hedera type (MRXSH) and X-linked parkinsonism with spasticity (XPDS) in humans, was defective as a V-ATPase-associated protein. Prorenin had no effect on the biogenesis of active V-ATPase. The cleavage of ATP6AP2/PRR by furin seemed also dispensable for the biogenesis of active V-ATPase. We conclude that the N-terminal ECD of ATP6AP2/PRR, which is also involved in binding to prorenin or renin, is required for the biogenesis of active V-ATPase. The V-ATPase assembly occurs prior to its delivery to the trans-Golgi network and hence shedding of ATP6AP2/PRR would not affect the biogenesis of active V-ATPase.
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Affiliation(s)
- Kenichiro Kinouchi
- Division of Endocrinology, Metabolism, and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Atsuhiro Ichihara
- Department of Endocrinology and Hypertension, Tokyo Women’s Medical University, Tokyo, Japan
- * E-mail:
| | - Motoaki Sano
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Ge-Hong Sun-Wada
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women’s College, Kyoto, Japan
| | - Yoh Wada
- Division of Biological Sciences, Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Hiroki Ochi
- Division of Endocrinology, Metabolism, and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Toru Fukuda
- Division of Endocrinology, Metabolism, and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Kanako Bokuda
- Division of Endocrinology, Metabolism, and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Hideaki Kurosawa
- Division of Endocrinology, Metabolism, and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Naohiro Yoshida
- Department of Endocrinology and Hypertension, Tokyo Women’s Medical University, Tokyo, Japan
| | - Shu Takeda
- Division of Endocrinology, Metabolism, and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Keiichi Fukuda
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Hiroshi Itoh
- Division of Endocrinology, Metabolism, and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
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186
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McFarlane HE, Watanabe Y, Gendre D, Carruthers K, Levesque-Tremblay G, Haughn GW, Bhalerao RP, Samuels L. Cell wall polysaccharides are mislocalized to the Vacuole in echidna mutants. Plant Cell Physiol 2013; 54:1867-1880. [PMID: 24058145 DOI: 10.1093/pcp/pct129] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
During cell wall biosynthesis, the Golgi apparatus is the platform for cell wall matrix biosynthesis and the site of packaging, of both matrix polysaccharides and proteins, into secretory vesicles with the correct targeting information. The objective of this study was to dissect the post-Golgi trafficking of cell wall polysaccharides using echidna as a vesicle traffic mutant of Arabidopsis thaliana and the pectin-secreting cells of the seed coat as a model system. ECHIDNA encodes a trans-Golgi network (TGN)-localized protein, which was previously shown to be required for proper structure and function of the secretory pathway. In echidna mutants, some cell wall matrix polysaccharides accumulate inside cells, rather than being secreted to the apoplast. In this study, live cell imaging of fluorescent protein markers as well as transmission electron microscopy (TEM)/immunoTEM of cryofixed seed coat cells were used to examine the consequences of TGN disorganization in echidna mutants under conditions of high polysaccharide production and secretion. While in wild-type seed coat cells, pectin is secreted to the apical surface, in echidna, polysaccharides accumulate in post-Golgi vesicles, the central lytic vacuole and endoplasmic reticulum-derived bodies. In contrast, proteins were partially mistargeted to internal multilamellar membranes in echidna. These results suggest that while secretion of both cell wall polysaccharides and proteins at the TGN requires ECHIDNA, different vesicle trafficking components may mediate downstream events in their secretion from the TGN.
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Affiliation(s)
- Heather E McFarlane
- Department of Botany, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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187
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Huang MD, Chen TLL, Huang AH. Abundant type III lipid transfer proteins in Arabidopsis tapetum are secreted to the locule and become a constituent of the pollen exine. Plant Physiol 2013; 163:1218-29. [PMID: 24096413 PMCID: PMC3813645 DOI: 10.1104/pp.113.225706] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Accepted: 09/30/2013] [Indexed: 05/17/2023]
Abstract
Lipid transfer proteins (LTPs) are small secretory proteins in plants with defined lipid-binding structures for possible lipid exocytosis. Special groups of LTPs unique to the anther tapetum are abundant, but their functions are unclear. We studied a special group of LTPs, type III LTPs, in Arabidopsis (Arabidopsis thaliana). Their transcripts were restricted to the anther tapetum, with levels peaking at the developmental stage of maximal pollen-wall exine synthesis. We constructed an LTP-Green Fluorescent Protein (LTP-GFP) plasmid, transformed it into wild-type plants, and monitored LTP-GFP in developing anthers with confocal laser scanning microscopy. LTP-GFP appeared in the tapetum and was secreted via the endoplasmic reticulum-trans-Golgi network machinery into the locule. It then moved to the microspore surface and remained as a component of exine. Immuno-transmission electron microscopy of native LTP in anthers confirmed the LTP-GFP observations. The in vivo association of LTP-GFP and exine in anthers was not observed with non-type III or structurally modified type III LTPs or in transformed exine-defective mutant plants. RNA interference knockdown of individual type III LTPs produced no observable mutant phenotypes. RNA interference knockdown of two type III LTPs produced microscopy-observable morphologic changes in the intine underneath the exine (presumably as a consequence of changes in the exine not observed by transmission electron microscopy) and pollen susceptible to dehydration damage. Overall, we reveal a novel transfer pathway of LTPs in which LTPs bound or nonbound to exine precursors are secreted from the tapetum to become microspore exine constituents; this pathway explains the need for plentiful LTPs to incorporate into the abundant exine.
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188
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Wang JG, Li S, Zhao XY, Zhou LZ, Huang GQ, Feng C, Zhang Y. HAPLESS13, the Arabidopsis μ1 adaptin, is essential for protein sorting at the trans-Golgi network/early endosome. Plant Physiol 2013; 162:1897-910. [PMID: 23766365 PMCID: PMC3729769 DOI: 10.1104/pp.113.221051] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 06/11/2013] [Indexed: 05/20/2023]
Abstract
In plant cells, secretory and endocytic routes intersect at the trans-Golgi network (TGN)/early endosome (EE), where cargos are further sorted correctly and in a timely manner. Cargo sorting is essential for plant survival and therefore necessitates complex molecular machinery. Adaptor proteins (APs) play key roles in this process by recruiting coat proteins and selecting cargos for different vesicle carriers. The µ1 subunit of AP-1 in Arabidopsis (Arabidopsis thaliana) was recently identified at the TGN/EE and shown to be essential for cytokinesis. However, little was known about other cellular activities affected by mutations in AP-1 or the developmental consequences of such mutations. We report here that HAPLESS13 (HAP13), the Arabidopsis µ1 adaptin, is essential for protein sorting at the TGN/EE. Functional loss of HAP13 displayed pleiotropic developmental defects, some of which were suggestive of disrupted auxin signaling. Consistent with this, the asymmetric localization of PIN-FORMED2 (PIN2), an auxin transporter, was compromised in the mutant. In addition, cell morphogenesis was disrupted. We further demonstrate that HAP13 is critical for brefeldin A-sensitive but wortmannin-insensitive post-Golgi trafficking. Our results show that HAP13 is a key link in the sophisticated trafficking network in plant cells.
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189
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Matsudaira T, Uchida Y, Tanabe K, Kon S, Watanabe T, Taguchi T, Arai H. SMAP2 regulates retrograde transport from recycling endosomes to the Golgi. PLoS One 2013; 8:e69145. [PMID: 23861959 PMCID: PMC3704519 DOI: 10.1371/journal.pone.0069145] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 06/03/2013] [Indexed: 02/04/2023] Open
Abstract
Retrograde transport is where proteins and lipids are transported back from the plasma membrane (PM) and endosomes to the Golgi, and crucial for a diverse range of cellular functions. Recycling endosomes (REs) serve as a sorting station for the retrograde transport and we recently identified evection-2, an RE protein with a pleckstrin homology (PH) domain, as an essential factor of this pathway. How evection-2 regulates retrograde transport from REs to the Golgi is not well understood. Here, we report that evection-2 binds to SMAP2, an Arf GTPase-activating protein. Endogenous SMAP2 localized mostly in REs and to a lesser extent, the trans-Golgi network (TGN). SMAP2 binds evection-2, and the RE localization of SMAP2 was abolished in cells depleted of evection-2. Knockdown of SMAP2, like that of evection-2, impaired the retrograde transport of cholera toxin B subunit (CTxB) from REs. These findings suggest that evection-2 recruits SMAP2 to REs, thereby regulating the retrograde transport of CTxB from REs to the Golgi.
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Affiliation(s)
- Tatsuyuki Matsudaira
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Yasunori Uchida
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Kenji Tanabe
- Medical Research Institute, Tokyo Women’s Medical University, Tokyo, Japan
| | - Shunsuke Kon
- Department of Molecular Immunology, Institute of Development, Aging and Cancer, Tohoku University, Sendai-shi, Miyagi, Japan
| | - Toshio Watanabe
- Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women’s University, Nara-shi, Nara, Japan
| | - Tomohiko Taguchi
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
- Pathological Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
- * E-mail: (TT) (HA)
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
- Pathological Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
- * E-mail: (TT) (HA)
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190
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Bohl CR, Abrahamyan LG, Wood C. Human Ubc9 is involved in intracellular HIV-1 Env stability after trafficking out of the trans-Golgi network in a Gag dependent manner. PLoS One 2013; 8:e69359. [PMID: 23861967 PMCID: PMC3704627 DOI: 10.1371/journal.pone.0069359] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 06/07/2013] [Indexed: 01/03/2023] Open
Abstract
The cellular E2 Sumo conjugase, Ubc9 interacts with HIV-1 Gag, and is important for the assembly of infectious HIV-1 virions. In the previous study we demonstrated that in the absence of Ubc9, a defect in virion assembly was associated with decreased levels of mature intracellular Envelope (Env) that affected Env incorporation into virions and virion infectivity. We have further characterized the effect of Ubc9 knockdown on HIV Env processing and assembly. We found that gp160 stability in the endoplasmic reticulum (ER) and its trafficking to the trans-Golgi network (TGN) were unaffected, indicating that the decreased intracellular mature Env levels in Ubc9-depleted cells were due to a selective degradation of mature Env gp120 after cleavage from gp160 and trafficked out of the TGN. Decreased levels of Gag and mature Env were found to be associated with the plasma membrane and lipid rafts, which suggest that these viral proteins were not trafficked correctly to the assembly site. Intracellular gp120 were partially rescued when treated with a combination of lysosome inhibitors. Taken together our results suggest that in the absence of Ubc9, gp120 is preferentially degraded in the lysosomes likely before trafficking to assembly sites leading to the production of defective virions. This study provides further insight in the processing and packaging of the HIV-1 gp120 into mature HIV-1 virions.
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Affiliation(s)
- Christopher R. Bohl
- Nebraska Center for Virology and the School of Biological Sciences, University of Nebraska, Lincoln, Lincoln, Nebraska, United States of America
| | - Levon G. Abrahamyan
- Nebraska Center for Virology and the School of Biological Sciences, University of Nebraska, Lincoln, Lincoln, Nebraska, United States of America
| | - Charles Wood
- Nebraska Center for Virology and the School of Biological Sciences, University of Nebraska, Lincoln, Lincoln, Nebraska, United States of America
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191
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Gendre D, McFarlane HE, Johnson E, Mouille G, Sjödin A, Oh J, Levesque-Tremblay G, Watanabe Y, Samuels L, Bhalerao RP. Trans-Golgi network localized ECHIDNA/Ypt interacting protein complex is required for the secretion of cell wall polysaccharides in Arabidopsis. Plant Cell 2013; 25:2633-46. [PMID: 23832588 PMCID: PMC3753388 DOI: 10.1105/tpc.113.112482] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The secretion of cell wall polysaccharides through the trans-Golgi network (TGN) is required for plant cell elongation. However, the components mediating the post-Golgi secretion of pectin and hemicellulose, the two major cell wall polysaccharides, are largely unknown. We identified evolutionarily conserved YPT/RAB GTPase Interacting Protein 4a (YIP4a) and YIP4b (formerly YIP2), which form a TGN-localized complex with ECHIDNA (ECH) in Arabidopsis thaliana. The localization of YIP4 and ECH proteins at the TGN is interdependent and influences the localization of VHA-a1 and SYP61, which are key components of the TGN. YIP4a and YIP4b act redundantly, and the yip4a yip4b double mutants have a cell elongation defect. Genetic, biochemical, and cell biological analyses demonstrate that the ECH/YIP4 complex plays a key role in TGN-mediated secretion of pectin and hemicellulose to the cell wall in dark-grown hypocotyls and in secretory cells of the seed coat. In keeping with these observations, Fourier transform infrared microspectroscopy analysis revealed that the ech and yip4a yip4b mutants exhibit changes in their cell wall composition. Overall, our results reveal a TGN subdomain defined by ECH/YIP4 that is required for the secretion of pectin and hemicellulose and distinguishes the role of the TGN in secretion from its roles in endocytic and vacuolar trafficking.
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Affiliation(s)
- Delphine Gendre
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83 Umea, Sweden
| | - Heather E. McFarlane
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Errin Johnson
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83 Umea, Sweden
| | - Gregory Mouille
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique–AgroParisTech, Institut National de la Recherche Agronomique Centre de Versailles-Grignon, 78026 Versailles cedex, France
| | - Andreas Sjödin
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83 Umea, Sweden
| | - Jaesung Oh
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83 Umea, Sweden
| | | | - Yoichiro Watanabe
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Lacey Samuels
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Rishikesh P. Bhalerao
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83 Umea, Sweden
- Address correspondence to
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192
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Dooley R, Angibaud E, Yusef YR, Thomas W, Harvey BJ. Aldosterone-induced ENaC and basal Na+/K+-ATPase trafficking via protein kinase D1-phosphatidylinositol 4-kinaseIIIβ trans Golgi signalling in M1 cortical collecting duct cells. Mol Cell Endocrinol 2013; 372:86-95. [PMID: 23541637 DOI: 10.1016/j.mce.2013.03.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 02/11/2013] [Accepted: 03/15/2013] [Indexed: 01/06/2023]
Abstract
Aldosterone regulates Na(+) transport in the distal nephron through multiple mechanisms that include the transcriptional control of epithelial sodium channel (ENaC) and Na(+)/K(+)-ATPase subunits. Aldosterone also induces the rapid phosphorylation of Protein Kinase D1 (PKD1). PKD isoforms regulate protein trafficking, by the control of vesicle fission from the trans Golgi network (TGN) through activation of phosphatidylinositol 4-kinaseIIIβ (PI4KIIIβ). We report rapid ENaCγ translocation to the plasma membrane after 30 min aldosterone treatment in polarized M1 cortical collecting duct cells, which was significantly impaired in PKD1 shRNA-mediated knockdown cells. In PKD1-deficient cells, the ouabain-sensitive current was significantly reduced and Na(+)/K(+)-ATPase α and β subunits showed aberrant localization. PKD1 and PI4KIIIβ localize to the TGN, and aldosterone induced an interaction between PKD1 and PI4KIIIβ following aldosterone treatment. This study reveals a novel mechanism for rapid regulation of ENaC and the Na(+)/K(+)-ATPase, via directed trafficking through PKD1-PI4KIIIβ signalling at the level of the TGN.
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Affiliation(s)
- Ruth Dooley
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland.
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193
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Bian S, Navaratnam D, Santos-Sacchi J. Real time measures of prestin charge and fluorescence during plasma membrane trafficking reveal sub-tetrameric activity. PLoS One 2013; 8:e66078. [PMID: 23762468 PMCID: PMC3677934 DOI: 10.1371/journal.pone.0066078] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 05/01/2013] [Indexed: 11/18/2022] Open
Abstract
Prestin (SLC26a5) is the outer hair cell integral membrane motor protein that drives cochlear amplification, and has been described as an obligate tetramer. We studied in real time the delivery of YFP-prestin to the plasma membrane of cells from a tetracycline-inducible cell line. Following the release of temperature block to reinstate trans Golgi network delivery of the integral membrane protein, we measured nonlinear capacitance (NLC) and membrane fluorescence during voltage clamp. Prestin was delivered exponentially to the plasma membrane with a time constant of less than 10 minutes, with both electrical and fluorescence methods showing high temporal correlation. However, based on disparity between estimates of prestin density derived from either fluorescence or NLC, we conclude that sub-tetrameric forms of prestin contribute to our electrical and fluorescence measures. Thus, in agreement with previous observations we find that functional prestin is not an obligate tetramer.
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Affiliation(s)
- Shumin Bian
- Department of Surgery (Otolaryngology), Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Dhasakumar Navaratnam
- Department of Surgery (Otolaryngology), Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Joseph Santos-Sacchi
- Department of Surgery (Otolaryngology), Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- * E-mail:
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194
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Modi S, Nizak C, Surana S, Halder S, Krishnan Y. Two DNA nanomachines map pH changes along intersecting endocytic pathways inside the same cell. Nat Nanotechnol 2013; 8:459-67. [PMID: 23708428 DOI: 10.1038/nnano.2013.92] [Citation(s) in RCA: 251] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 04/22/2013] [Indexed: 05/18/2023]
Abstract
DNA is a versatile scaffold for molecular sensing in living cells, and various cellular applications of DNA nanodevices have been demonstrated. However, the simultaneous use of different DNA nanodevices within the same living cell remains a challenge. Here, we show that two distinct DNA nanomachines can be used simultaneously to map pH gradients along two different but intersecting cellular entry pathways. The two nanomachines, which are molecularly programmed to enter cells via different pathways, can map pH changes within well-defined subcellular environments along both pathways inside the same cell. We applied these nanomachines to probe the pH of early endosomes and the trans-Golgi network, in real time. When delivered either sequentially or simultaneously, both nanomachines localized into and independently captured the pH of the organelles for which they were designed. The successful functioning of DNA nanodevices within living systems has important implications for sensing and therapies in a diverse range of contexts.
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Affiliation(s)
- Souvik Modi
- National Centre for Biological Sciences, TIFR, GKVK, Bellary Road, Bangalore 560065, India
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195
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Sauer M, Delgadillo MO, Zouhar J, Reynolds GD, Pennington JG, Jiang L, Liljegren SJ, Stierhof YD, De Jaeger G, Otegui MS, Bednarek SY, Rojo E. MTV1 and MTV4 encode plant-specific ENTH and ARF GAP proteins that mediate clathrin-dependent trafficking of vacuolar cargo from the trans-Golgi network. Plant Cell 2013; 25:2217-35. [PMID: 23771894 PMCID: PMC3723622 DOI: 10.1105/tpc.113.111724] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/14/2013] [Accepted: 05/30/2013] [Indexed: 05/18/2023]
Abstract
Many soluble proteins transit through the trans-Golgi network (TGN) and the prevacuolar compartment (PVC) en route to the vacuole, but our mechanistic understanding of this vectorial trafficking step in plants is limited. In particular, it is unknown whether clathrin-coated vesicles (CCVs) participate in this transport step. Through a screen for modified transport to the vacuole (mtv) mutants that secrete the vacuolar protein VAC2, we identified MTV1, which encodes an epsin N-terminal homology protein, and MTV4, which encodes the ADP ribosylation factor GTPase-activating protein nevershed/AGD5. MTV1 and NEV/AGD5 have overlapping expression patterns and interact genetically to transport vacuolar cargo and promote plant growth, but they have no apparent roles in protein secretion or endocytosis. MTV1 and NEV/AGD5 colocalize with clathrin at the TGN and are incorporated into CCVs. Importantly, mtv1 nev/agd5 double mutants show altered subcellular distribution of CCV cargo exported from the TGN. Moreover, MTV1 binds clathrin in vitro, and NEV/AGD5 associates in vivo with clathrin, directly linking these proteins to CCV formation. These results indicate that MTV1 and NEV/AGD5 are key effectors for CCV-mediated trafficking of vacuolar proteins from the TGN to the PVC in plants.
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Affiliation(s)
- Michael Sauer
- Departamento Molecular de Plantas, Centro Nacional de Biotecnología (Consejo Superior de Investigaciones Cientificas), 28049 Madrid, Spain
| | - M. Otilia Delgadillo
- Departamento Molecular de Plantas, Centro Nacional de Biotecnología (Consejo Superior de Investigaciones Cientificas), 28049 Madrid, Spain
| | - Jan Zouhar
- Departamento Molecular de Plantas, Centro Nacional de Biotecnología (Consejo Superior de Investigaciones Cientificas), 28049 Madrid, Spain
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica, 28223 Madrid, Spain
| | | | | | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Sarah J. Liljegren
- Department of Biology, University of Mississippi, Oxford, Mississippi 38677-1848
| | - York-Dieter Stierhof
- Zentrum für Molekularbiologie der Pflanzen, University of Tübingen, 72076 Tuebingen, Germany
| | - Geert De Jaeger
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Marisa S. Otegui
- Department of Botany, University of Madison, Madison, Wisconsin 53706
| | | | - Enrique Rojo
- Departamento Molecular de Plantas, Centro Nacional de Biotecnología (Consejo Superior de Investigaciones Cientificas), 28049 Madrid, Spain
- Address correspondence to
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196
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Qi X, Zheng H. Rab-A1c GTPase defines a population of the trans-Golgi network that is sensitive to endosidin1 during cytokinesis in Arabidopsis. Mol Plant 2013; 6:847-59. [PMID: 23075992 DOI: 10.1093/mp/sss116] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
In plant cells, Rab-A proteins have been implicated to play important roles in membrane trafficking from the trans-Golgi network (TGN) to the plasma membrane/cell wall and to the newly formed cell plate in cytokinesis. But how different Rab-A proteins may work in the TGN is not well studied. We show here that RAB-A1c defines a population of TGN that is partially overlapped with the VHA-a1 marked-TGN. Interestingly, the morphology of RAB-A1c defined-TGN is sensitive to endosidin 1 (ES1), but not to wortmannin. In mitotic cells, RAB-A1c is relocated to the cell plate. We revealed that this process could be interrupted by ES1, but not by wortmannin. In addition, root growth and cytokinesis in root mitotic cells of rab-a1a/b/c triple mutant seedlings are hypersensitive to lower concentrations of ES1. ES1 is known to selectively block the transport of several plasma membrane auxin transporters, including PIN2 and AUX1 at the TGN. Together with the known facts that members of Rab-A1 proteins are involved in auxin-mediated responses in root growth and that mutations in TRAPPII, a protein complex that acts upstream of RAB-A1c, also selectively impair the transport of PIN2 and AUX1 at the TGN, we propose that the Rab-A1-mediated trafficking pathways around the TGN, but not Rab-A1s directly, are the target of ES1.
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Affiliation(s)
- Xingyun Qi
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, Quebec H3A 1B1, Canada
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Holst B, Madsen KL, Jansen AM, Jin C, Rickhag M, Lund VK, Jensen M, Bhatia V, Sørensen G, Madsen AN, Xue Z, Møller SK, Woldbye D, Qvortrup K, Huganir R, Stamou D, Kjærulff O, Gether U. PICK1 deficiency impairs secretory vesicle biogenesis and leads to growth retardation and decreased glucose tolerance. PLoS Biol 2013; 11:e1001542. [PMID: 23630454 PMCID: PMC3635866 DOI: 10.1371/journal.pbio.1001542] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 03/12/2013] [Indexed: 01/02/2023] Open
Abstract
Two lipid membrane sculpting BAR domain proteins, PICK1 and ICA69, play a key role early in the biogenesis of peptide hormone secretory vesicles and are critical for normal growth and metabolic homeostasis. Secretory vesicles in endocrine cells store hormones such as growth hormone (GH) and insulin before their release into the bloodstream. The molecular mechanisms governing budding of immature secretory vesicles from the trans-Golgi network (TGN) and their subsequent maturation remain unclear. Here, we identify the lipid binding BAR (Bin/amphiphysin/Rvs) domain protein PICK1 (protein interacting with C kinase 1) as a key component early in the biogenesis of secretory vesicles in GH-producing cells. Both PICK1-deficient Drosophila and mice displayed somatic growth retardation. Growth retardation was rescued in flies by reintroducing PICK1 in neurosecretory cells producing somatotropic peptides. PICK1-deficient mice were characterized by decreased body weight and length, increased fat accumulation, impaired GH secretion, and decreased storage of GH in the pituitary. Decreased GH storage was supported by electron microscopy showing prominent reduction in secretory vesicle number. Evidence was also obtained for impaired insulin secretion associated with decreased glucose tolerance. PICK1 localized in cells to immature secretory vesicles, and the PICK1 BAR domain was shown by live imaging to associate with vesicles budding from the TGN and to possess membrane-sculpting properties in vitro. In mouse pituitary, PICK1 co-localized with the BAR domain protein ICA69, and PICK1 deficiency abolished ICA69 protein expression. In the Drosophila brain, PICK1 and ICA69 co-immunoprecipitated and showed mutually dependent expression. Finally, both in a Drosophila model of type 2 diabetes and in high-fat-diet-induced obese mice, we observed up-regulation of PICK1 mRNA expression. Our findings suggest that PICK1, together with ICA69, is critical during budding of immature secretory vesicles from the TGN and thus for vesicular storage of GH and possibly other hormones. The data link two BAR domain proteins to membrane remodeling processes in the secretory pathway of peptidergic endocrine cells and support an important role of PICK1/ICA69 in maintenance of metabolic homeostasis. Regulated secretion of peptide hormones, such as growth hormone (GH) and insulin, represents a fundamental process in controlling physiological homeostasis. In endocrine cells, hormone-containing vesicles bud from the Golgi apparatus to enable storage and regulated release into the blood stream. Here we show that two proteins with a lipid membrane-shaping BAR domain, PICK1 and ICA69, work together in the pituitary gland and the pancreas to facilitate the budding of early secretory vesicle from the Golgi apparatus. The physiological significance of our findings was borne out by showing that mice and Drosophila flies lacking the PICK1 encoding gene have marked growth retardation. PICK1-deficient mice showed increased fat accumulation, reduced body weight and length, as well as reduced glucose clearance from the blood stream. Consistent with these findings, we observed a severe reduction in GH storage in the pituitary and impaired secretion of both insulin and GH in response to physiological stimuli. Finally, we found that PICK1 expression levels were raised in a fly model of type 2 diabetes and in high-fat-diet-induced obese mice. These results indicate that alteration of PICK1 expression might play a role in pathophysiological processes of metabolic diseases and/or in a protective compensatory mechanism.
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Affiliation(s)
- Birgitte Holst
- Laboratory for Molecular Pharmacology, Novo Nordisk Foundation Center for Basic Metabolic Research, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (BH); (OK); (UG)
| | - Kenneth L. Madsen
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Molecular Neuropharmacology Laboratory, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Anna M. Jansen
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Molecular Neuropharmacology Laboratory, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Chunyu Jin
- Laboratory for Molecular Pharmacology, Novo Nordisk Foundation Center for Basic Metabolic Research, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Mattias Rickhag
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Molecular Neuropharmacology Laboratory, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Viktor K. Lund
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Morten Jensen
- Laboratory for Molecular Pharmacology, Novo Nordisk Foundation Center for Basic Metabolic Research, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Vikram Bhatia
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- BioNano Laboratory, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Gunnar Sørensen
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Molecular Neuropharmacology Laboratory, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Andreas N. Madsen
- Laboratory for Molecular Pharmacology, Novo Nordisk Foundation Center for Basic Metabolic Research, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Zhichao Xue
- Laboratory for Molecular Pharmacology, Novo Nordisk Foundation Center for Basic Metabolic Research, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Siri K. Møller
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Molecular Neuropharmacology Laboratory, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - David Woldbye
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Klaus Qvortrup
- Core Facility for Integrated Microscopy, Department of Biomedical Science, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Richard Huganir
- Department of Neuroscience, The Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Dimitrios Stamou
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- BioNano Laboratory, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Ole Kjærulff
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (BH); (OK); (UG)
| | - Ulrik Gether
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Molecular Neuropharmacology Laboratory, The Faculty of Health Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (BH); (OK); (UG)
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198
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Morvan J, Gehart H, Ricci R. [Arfaptine-1 controls secretory granule biogenesis]. Med Sci (Paris) 2013; 29:247-9. [PMID: 23544374 DOI: 10.1051/medsci/2013293006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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199
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Yang H, Richter GL, Wang X, Młodzińska E, Carraro N, Ma G, Jenness M, Chao DY, Peer WA, Murphy AS. Sterols and sphingolipids differentially function in trafficking of the Arabidopsis ABCB19 auxin transporter. Plant J 2013; 74:37-47. [PMID: 23279701 DOI: 10.1111/tpj.12103] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/06/2012] [Accepted: 12/12/2012] [Indexed: 05/21/2023]
Abstract
The Arabidopsis ATP-binding cassette B19 (ABCB19, P-glycoprotein19) transporter functions coordinately with ABCB1 and PIN1 to motivate long-distance transport of the phytohormone auxin from the shoot to root apex. ABCB19 exhibits a predominantly apolar plasma membrane (PM) localization and stabilizes PIN1 when the two proteins co-occur. Biochemical evidence associates ABCB19 and PIN1 with sterol- and sphingolipid-enriched PM fractions. Mutants deficient in structural sterols and sphingolipids exhibit similarity to abcb19 mutants. Sphingolipid-defective tsc10a mutants and, to a lesser extent, sterol-deficient cvp1 mutants phenocopy abcb19 mutants. Live imaging studies show that sterols function in trafficking of ABCB19 from the trans-Golgi network to the PM. Pharmacological or genetic sphingolipid depletion has an even greater impact on ABCB19 PM targeting and interferes with ABCB19 trafficking from the Golgi. Our results also show that sphingolipids function in trafficking associated with compartments marked by the VTI12 syntaxin, and that ABCB19 mediates PIN1 stability in sphingolipid-containing membranes. The TWD1/FKBP42 co-chaperone immunophilin is required for exit of ABCB19 from the ER, but ABCB19 interactions with sterols, sphingolipids and PIN1 are spatially distinct from FKBP42 activity at the ER. The accessibility of this system to direct live imaging and biochemical analysis makes it ideal for the modeling and analysis of sterol and sphingolipid regulation of ABCB/P-glycoprotein transporters.
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Affiliation(s)
- Haibing Yang
- Department of Horticulture, Purdue University, 625 Agriculture Mall Drive, West Lafayette, IN 47907-2010, USA
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200
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Choi SW, Tamaki T, Ebine K, Uemura T, Ueda T, Nakano A. RABA members act in distinct steps of subcellular trafficking of the FLAGELLIN SENSING2 receptor. Plant Cell 2013; 25:1174-87. [PMID: 23532067 PMCID: PMC3634684 DOI: 10.1105/tpc.112.108803] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 02/26/2013] [Accepted: 03/14/2013] [Indexed: 05/18/2023]
Abstract
Cell surface proteins play critical roles in the perception of environmental stimuli at the plasma membrane (PM) and ensuing signal transduction. Intracellular localization of such proteins must be strictly regulated, which requires elaborate integration of exocytic and endocytic trafficking pathways. Subcellular localization of Arabidopsis thaliana FLAGELLIN SENSING2 (FLS2), a receptor that recognizes bacterial flagellin, also depends on membrane trafficking. However, our understanding about the mechanisms involved is still limited. In this study, we visualized ligand-induced endocytosis of FLS2 using green fluorescent protein (GFP)-tagged FLS2 expressed in Nicotiana benthamiana. Upon treatment with the flg22 peptide, internalized FLS2-GFP from the PM was transported to a compartment with properties intermediate between the trans-Golgi network (TGN) and the multivesicular endosome. This compartment gradually discarded the TGN characteristics as it continued along the trafficking pathway. We further found that FLS2 endocytosis involves distinct RABA/RAB11 subgroups at different steps. Moreover, we demonstrated that transport of de novo-synthesized FLS2 to the PM also involves a distinct RABA/RAB11 subgroup. Our results demonstrate the complex regulatory system for properly localizing FLS2 and functional differentiation in RABA members in endo- and exocytosis.
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Affiliation(s)
- Seung-won Choi
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takayuki Tamaki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kazuo Ebine
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tomohiro Uemura
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takashi Ueda
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
- Japan Science and Technology Agency, PRESTO, Saitama 332-0012, Japan
| | - Akihiko Nakano
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
- Molecular Membrane Biology Laboratory, RIKEN Advanced Science Institute, Wako, Saitama 351-0198, Japan
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