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Ma X, Zhao X, Zhang H, Zhang Y, Sun S, Li Y, Long Z, Liu Y, Zhang X, Li R, Tan L, Jiang L, Zhu JK, Li L. MAG2 and MAL Regulate Vesicle Trafficking and Auxin Homeostasis With Functional Redundancy. FRONTIERS IN PLANT SCIENCE 2022; 13:849532. [PMID: 35371137 PMCID: PMC8966843 DOI: 10.3389/fpls.2022.849532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
Auxin is a central phytohormone and controls almost all aspects of plant development and stress response. Auxin homeostasis is coordinately regulated by biosynthesis, catabolism, transport, conjugation, and deposition. Endoplasmic reticulum (ER)-localized MAIGO2 (MAG2) complex mediates tethering of arriving vesicles to the ER membrane, and it is crucial for ER export trafficking. Despite important regulatory roles of MAG2 in vesicle trafficking, the mag2 mutant had mild developmental abnormalities. MAG2 has one homolog protein, MAG2-Like (MAL), and the mal-1 mutant also had slight developmental phenotypes. In order to investigate MAG2 and MAL regulatory function in plant development, we generated the mag2-1 mal-1 double mutant. As expected, the double mutant exhibited serious developmental defects and more alteration in stress response compared with single mutants and wild type. Proteomic analysis revealed that signaling, metabolism, and stress response in mag2-1 mal-1 were affected, especially membrane trafficking and auxin biosynthesis, signaling, and transport. Biochemical and cell biological analysis indicated that the mag2-1 mal-1 double mutant had more serious defects in vesicle transport than the mag2-1 and mal-1 single mutants. The auxin distribution and abundance of auxin transporters were altered significantly in the mag2-1 and mal-1 single mutants and mag2-1 mal-1 double mutant. Our findings suggest that MAG2 and MAL regulate plant development and auxin homeostasis by controlling membrane trafficking, with functional redundancy.
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Affiliation(s)
- Xiaohui Ma
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Xiaonan Zhao
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Hailong Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Yiming Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Shanwen Sun
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Ying Li
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Zhengbiao Long
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Yuqi Liu
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Xiaomeng Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Rongxia Li
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Li Tan
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lixi Jiang
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lixin Li
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
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Narasimhan M, Johnson A, Prizak R, Kaufmann WA, Tan S, Casillas-Pérez B, Friml J. Evolutionarily unique mechanistic framework of clathrin-mediated endocytosis in plants. eLife 2020; 9:52067. [PMID: 31971511 PMCID: PMC7012609 DOI: 10.7554/elife.52067] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/22/2020] [Indexed: 12/13/2022] Open
Abstract
In plants, clathrin mediated endocytosis (CME) represents the major route for cargo internalisation from the cell surface. It has been assumed to operate in an evolutionary conserved manner as in yeast and animals. Here we report characterisation of ultrastructure, dynamics and mechanisms of plant CME as allowed by our advancement in electron microscopy and quantitative live imaging techniques. Arabidopsis CME appears to follow the constant curvature model and the bona fide CME population generates vesicles of a predominantly hexagonal-basket type; larger and with faster kinetics than in other models. Contrary to the existing paradigm, actin is dispensable for CME events at the plasma membrane but plays a unique role in collecting endocytic vesicles, sorting of internalised cargos and directional endosome movement that itself actively promote CME events. Internalized vesicles display a strongly delayed and sequential uncoating. These unique features highlight the independent evolution of the plant CME mechanism during the autonomous rise of multicellularity in eukaryotes.
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Affiliation(s)
| | - Alexander Johnson
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Roshan Prizak
- Institute of Science and Technology Austria, Klosterneuburg, Austria.,Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | | | - Shutang Tan
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Jiří Friml
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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Blackburn JB, D'Souza Z, Lupashin VV. Maintaining order: COG complex controls Golgi trafficking, processing, and sorting. FEBS Lett 2019; 593:2466-2487. [PMID: 31381138 PMCID: PMC6771879 DOI: 10.1002/1873-3468.13570] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 12/31/2022]
Abstract
The conserved oligomeric Golgi (COG) complex, a multisubunit tethering complex of the CATCHR (complexes associated with tethering containing helical rods) family, controls membrane trafficking and ensures Golgi homeostasis by orchestrating retrograde vesicle targeting within the Golgi. In humans, COG defects lead to severe multisystemic diseases known as COG-congenital disorders of glycosylation (COG-CDG). The COG complex both physically and functionally interacts with all classes of molecules maintaining intra-Golgi trafficking, namely SNAREs, SNARE-interacting proteins, Rabs, coiled-coil tethers, and vesicular coats. Here, we review our current knowledge of COG-related trafficking and glycosylation defects in humans and model organisms, and analyze possible scenarios for the molecular mechanism of the COG orchestrated vesicle targeting.
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Affiliation(s)
- Jessica B. Blackburn
- Department of Physiology and BiophysicsUniversity of Arkansas for Medical SciencesLittle RockARUSA
- Present address:
Division of Allergy, Pulmonary and Critical Care MedicineDepartment of MedicineVanderbilt University Medical CenterNashvilleTNUSA
| | - Zinia D'Souza
- Department of Physiology and BiophysicsUniversity of Arkansas for Medical SciencesLittle RockARUSA
| | - Vladimir V. Lupashin
- Department of Physiology and BiophysicsUniversity of Arkansas for Medical SciencesLittle RockARUSA
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Abstract
The Golgi apparatus is a central sorting station in the cell. It receives newly synthesized molecules from the endoplasmic reticulum and directs them to different subcellular destinations, such as the plasma membrane or the endocytic pathway. Importantly, in the last few years, it has emerged that the maintenance of Golgi structure is connected to the proper regulation of membrane trafficking. Rab proteins are small GTPases that are considered to be the master regulators of the intracellular membrane trafficking. Several of the over 60 human Rabs are involved in the regulation of transport pathways at the Golgi as well as in the maintenance of its architecture. This chapter will summarize the different roles of Rab GTPases at the Golgi, both as regulators of membrane transport, scaffold, and tethering proteins and in preserving the structure and function of this organelle.
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5
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Steinbuck MP, Winandy S. A Review of Notch Processing With New Insights Into Ligand-Independent Notch Signaling in T-Cells. Front Immunol 2018; 9:1230. [PMID: 29910816 PMCID: PMC5992298 DOI: 10.3389/fimmu.2018.01230] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/16/2018] [Indexed: 12/12/2022] Open
Abstract
The Notch receptor is an evolutionarily highly conserved transmembrane protein essential to a wide spectrum of cellular systems, and its deregulation has been linked to a vast number of developmental disorders and malignancies. Regulated Notch function is critical for the generation of T-cells, in which abnormal Notch signaling results in leukemia. Notch activation through trans-activation of the receptor by one of its ligands expressed on adjacent cells has been well defined. In this canonical ligand-dependent pathway, Notch receptor undergoes conformational changes upon ligand engagement, stimulated by a pulling-force on the extracellular fragment of Notch that results from endocytosis of the receptor-bound ligand into the ligand-expressing cell. These conformational changes in the receptor allow for two consecutive proteolytic cleavage events to occur, which release the intracellular region of the receptor into the cytoplasm. It can then travel to the nucleus, where it induces gene transcription. However, there is accumulating evidence that other pathways may induce Notch signaling. A ligand-independent mechanism of Notch activation has been described in which receptor processing is initiated via cell-internal signals. These signals result in the internalization of Notch into endosomal compartments, where chemical changes existing in this microenvironment result in the conformational modifications required for receptor processing. This review will present mechanisms underlying both canonical ligand-dependent and non-canonical ligand-independent Notch activation pathways and discuss the latter in the context of Notch signaling in T-cells.
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Affiliation(s)
- Martin Peter Steinbuck
- Immunology Training Program, Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, United States
| | - Susan Winandy
- Immunology Training Program, Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, United States
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Makaraci P, Kim K. trans-Golgi network-bound cargo traffic. Eur J Cell Biol 2018; 97:137-149. [PMID: 29398202 DOI: 10.1016/j.ejcb.2018.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/15/2017] [Accepted: 01/16/2018] [Indexed: 12/19/2022] Open
Abstract
Cargo following the retrograde trafficking are sorted at endosomes to be targeted the trans-Golgi network (TGN), a central receiving organelle. Though molecular requirements and their interaction networks have been somewhat established, the complete understanding of the intricate nature of their action mechanisms in every step of the retrograde traffic pathway remains unachieved. This review focuses on elucidating known functions of key regulators, including scission factors at the endosome and tethering/fusion mediators at the receiving dock, TGN, as well as a diverse range of cargo.
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Affiliation(s)
- Pelin Makaraci
- Department of Biology, Missouri State University, 901 S National Ave., Springfield, MO 65807, USA
| | - Kyoungtae Kim
- Department of Biology, Missouri State University, 901 S National Ave., Springfield, MO 65807, USA.
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Bärlocher K, Welin A, Hilbi H. Formation of the Legionella Replicative Compartment at the Crossroads of Retrograde Trafficking. Front Cell Infect Microbiol 2017; 7:482. [PMID: 29226112 PMCID: PMC5706426 DOI: 10.3389/fcimb.2017.00482] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/06/2017] [Indexed: 12/13/2022] Open
Abstract
Retrograde trafficking from the endosomal system through the Golgi apparatus back to the endoplasmic reticulum is an essential pathway in eukaryotic cells, serving to maintain organelle identity and to recycle empty cargo receptors delivered by the secretory pathway. Intracellular replication of several bacterial pathogens, including Legionella pneumophila, is restricted by the retrograde trafficking pathway. L. pneumophila employs the Icm/Dot type IV secretion system (T4SS) to form the replication-permissive Legionella-containing vacuole (LCV), which is decorated with multiple components of the retrograde trafficking machinery as well as retrograde cargo receptors. The L. pneumophila effector protein RidL is secreted by the T4SS and interferes with retrograde trafficking. Here, we review recent evidence that the LCV interacts with the retrograde trafficking pathway, discuss the possible sites of action and function of RidL in the retrograde route, and put forth the hypothesis that the LCV is an acceptor compartment of retrograde transport vesicles.
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Affiliation(s)
- Kevin Bärlocher
- Institute of Medical Microbiology, University of Zürich, Zurich, Switzerland
| | - Amanda Welin
- Institute of Medical Microbiology, University of Zürich, Zurich, Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zürich, Zurich, Switzerland
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8
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Brandizzi F. Transport from the endoplasmic reticulum to the Golgi in plants: Where are we now? Semin Cell Dev Biol 2017; 80:94-105. [PMID: 28688928 DOI: 10.1016/j.semcdb.2017.06.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/11/2017] [Accepted: 06/27/2017] [Indexed: 11/26/2022]
Abstract
The biogenesis of about one third of the cellular proteome is initiated in the endoplasmic reticulum (ER), which exports proteins to the Golgi apparatus for sorting to their final destination. Notwithstanding the close proximity of the ER with other secretory membranes (e.g., endosomes, plasma membrane), the ER is also important for the homeostasis of non-secretory organelles such as mitochondria, peroxisomes, and chloroplasts. While how the plant ER interacts with most of the non-secretory membranes is largely unknown, the knowledge on the mechanisms for ER-to-Golgi transport is relatively more advanced. Indeed, over the last fifteen years or so, a large number of exciting results have contributed to draw parallels with non-plant species but also to highlight the complexity of the plant ER-Golgi interface, which bears unique features. This review reports and discusses results on plant ER-to-Golgi traffic, focusing mainly on research on COPII-mediated transport in the model species Arabidopsis thaliana.
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Affiliation(s)
- Federica Brandizzi
- MSU-DOE Plant Research Lab and Plant Biology Department, Michigan State University, East Lansing, MI 48824, USA; Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA; Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA.
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Misrouting of v-ATPase subunit V0a1 dysregulates lysosomal acidification in a neurodegenerative lysosomal storage disease model. Nat Commun 2017; 8:14612. [PMID: 28266544 PMCID: PMC5344305 DOI: 10.1038/ncomms14612] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 01/15/2017] [Indexed: 12/13/2022] Open
Abstract
Defective lysosomal acidification contributes to virtually all lysosomal storage disorders (LSDs) and to common neurodegenerative diseases like Alzheimer's and Parkinson's. Despite its fundamental importance, the mechanism(s) underlying this defect remains unclear. The v-ATPase, a multisubunit protein complex composed of cytosolic V1-sector and lysosomal membrane-anchored V0-sector, regulates lysosomal acidification. Mutations in the CLN1 gene, encoding PPT1, cause a devastating neurodegenerative LSD, INCL. Here we report that in Cln1−/− mice, which mimic INCL, reduced v-ATPase activity correlates with elevated lysosomal pH. Moreover, v-ATPase subunit a1 of the V0 sector (V0a1) requires palmitoylation for interacting with adaptor protein-2 (AP-2) and AP-3, respectively, for trafficking to the lysosomal membrane. Notably, treatment of Cln1−/− mice with a thioesterase (Ppt1)-mimetic, NtBuHA, ameliorated this defect. Our findings reveal an unanticipated role of Cln1 in regulating lysosomal targeting of V0a1 and suggest that varying factors adversely affecting v-ATPase function dysregulate lysosomal acidification in other LSDs and common neurodegenerative diseases. Lysosomal acidification defects have been implicated in various neurodegenerative disorders. Bagh et al. show that the V0a1 subunit of v-ATPase requires palmitoylation for correct sorting and trafficking to the lysosome membrane, and that such a process is impaired in a mouse model of a devastating neurodegenerative lysosomal storage disease, INCL.
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Traffic Through the Trans-Golgi Network and the Endosomal System Requires Collaboration Between Exomer and Clathrin Adaptors in Fission Yeast. Genetics 2016; 205:673-690. [PMID: 27974503 DOI: 10.1534/genetics.116.193458] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 12/09/2016] [Indexed: 11/18/2022] Open
Abstract
Despite its biological and medical relevance, traffic from the Golgi to the plasma membrane (PM) is one of the least understood steps of secretion. Exomer is a protein complex that mediates the trafficking of certain cargoes from the trans-Golgi network/early endosomes to the PM in budding yeast. Here, we show that in Schizosaccharomyces pombe the Cfr1 and Bch1 proteins constitute the simplest form of an exomer. Cfr1 co-immunoprecipitates with Assembly Polypeptide adaptor 1 (AP-1), AP-2, and Golgi-localized, gamma-adaptin ear domain homology, ARF-binding (GGA) subunits, and cfr1+ interacts genetically with AP-1 and GGA genes. Exomer-defective cells exhibit multiple mild defects, including alterations in the morphology of Golgi stacks and the distribution of the synaptobrevin-like Syb1 protein, carboxypeptidase missorting, and stress sensitivity. S. pombe apm1Δ cells exhibit a defect in trafficking through the early endosomes that is severely aggravated in the absence of exomer. apm1Δ cfr1Δ cells exhibit a dramatic disorganization of intracellular compartments, including massive accumulation of electron-dense tubulovesicular structures. While the trans-Golgi network/early endosomes are severely disorganized in the apm1Δ cfr1Δ strain, gga21Δ gga22Δ cfr1Δ cells exhibit a significant disturbance of the prevacuolar/vacuolar compartments. Our findings show that exomer collaborates with clathrin adaptors in trafficking through diverse cellular compartments, and that this collaboration is important to maintain their integrity. These results indicate that the effect of eliminating exomer is more pervasive than that described to date, and suggest that exomer complexes might participate in diverse steps of vesicle transport in other organisms.
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Patak J, Zhang-James Y, Faraone SV. Endosomal system genetics and autism spectrum disorders: A literature review. Neurosci Biobehav Rev 2016; 65:95-112. [PMID: 27048963 PMCID: PMC4866511 DOI: 10.1016/j.neubiorev.2016.03.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/25/2016] [Accepted: 03/27/2016] [Indexed: 01/01/2023]
Abstract
Autism spectrum disorders (ASDs) are a group of debilitating neurodevelopmental disorders thought to have genetic etiology, due to their high heritability. The endosomal system has become increasingly implicated in ASD pathophysiology. In an attempt to summarize the association between endosomal system genes and ASDs we performed a systematic review of the literature. We searched PubMed for relevant articles. Simons Foundation Autism Research Initiative (SFARI) gene database was used to exclude articles regarding genes with less than minimal evidence for association with ASDs. Our search retained 55 articles reviewed in two categories: genes that regulate and genes that are regulated by the endosomal system. Our review shows that the endosomal system is a novel pathway implicated in ASDs as well as other neuropsychiatric disorders. It plays a central role in aspects of cellular physiology on which neurons and glial cells are particularly reliant, due to their unique metabolic and functional demands. The system shows potential for biomarkers and pharmacological intervention and thus more research into this pathway is warranted.
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Affiliation(s)
- Jameson Patak
- Dept. of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, United States.
| | - Yanli Zhang-James
- Dept of Psychiatry, Upstate Medical University, Syracuse, NY, United States.
| | - Stephen V Faraone
- Dept. of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, United States; Dept of Psychiatry, Upstate Medical University, Syracuse, NY, United States; K.G. Jebsen Centre for Neuropsychiatric Disorders, Department of Biomedicine, University of Bergen, Bergen, Norway.
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12
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Schroeter S, Beckmann S, Schmitt HD. Coat/Tether Interactions-Exception or Rule? Front Cell Dev Biol 2016; 4:44. [PMID: 27243008 PMCID: PMC4868844 DOI: 10.3389/fcell.2016.00044] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 04/25/2016] [Indexed: 12/02/2022] Open
Abstract
Coat complexes are important for cargo selection and vesicle formation. Recent evidence suggests that they may also be involved in vesicle targeting. Tethering factors, which form an initial bridge between vesicles and the target membrane, may bind to coat complexes. In this review, we ask whether these coat/tether interactions share some common mechanisms, or whether they are special adaptations to the needs of very specific transport steps. We compare recent findings in two multisubunit tethering complexes, the Dsl1 complex and the HOPS complex, and put them into context with the TRAPP I complex as a prominent example for coat/tether interactions. We explore where coat/tether interactions are found, compare their function and structure, and comment on a possible evolution from a common ancestor of coats and tethers.
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Affiliation(s)
- Saskia Schroeter
- Neurobiology, Max Planck Institute for Biophysical Chemistry Göttingen, Germany
| | - Sabrina Beckmann
- Neurobiology, Max Planck Institute for Biophysical Chemistry Göttingen, Germany
| | - Hans Dieter Schmitt
- Neurobiology, Max Planck Institute for Biophysical Chemistry Göttingen, Germany
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13
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Helm JR, Bentley M, Thorsen KD, Wang T, Foltz L, Oorschot V, Klumperman J, Hay JC. Apoptosis-linked gene-2 (ALG-2)/Sec31 interactions regulate endoplasmic reticulum (ER)-to-Golgi transport: a potential effector pathway for luminal calcium. J Biol Chem 2014; 289:23609-28. [PMID: 25006245 DOI: 10.1074/jbc.m114.561829] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Luminal calcium released from secretory organelles has been suggested to play a regulatory role in vesicle transport at several steps in the secretory pathway; however, its functional roles and effector pathways have not been elucidated. Here we demonstrate for the first time that specific luminal calcium depletion leads to a significant decrease in endoplasmic reticulum (ER)-to-Golgi transport rates in intact cells. Ultrastructural analysis revealed that luminal calcium depletion is accompanied by increased accumulation of intermediate compartment proteins in COPII buds and clusters of unfused COPII vesicles at ER exit sites. Furthermore, we present several lines of evidence suggesting that luminal calcium affected transport at least in part through calcium-dependent interactions between apoptosis-linked gene-2 (ALG-2) and the Sec31A proline-rich region: 1) targeted disruption of ALG-2/Sec31A interactions caused severe defects in ER-to-Golgi transport in intact cells; 2) effects of luminal calcium and ALG-2/Sec31A interactions on transport mutually required each other; and 3) Sec31A function in transport required luminal calcium. Morphological phenotypes of disrupted ALG-2/Sec31A interactions were characterized. We found that ALG-2/Sec31A interactions were not required for the localization of Sec31A to ER exit sites per se but appeared to acutely regulate the stability and trafficking of the cargo receptor p24 and the distribution of the vesicle tether protein p115. These results represent the first outline of a mechanism that connects luminal calcium to specific protein interactions regulating vesicle trafficking machinery.
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Affiliation(s)
- Jared R Helm
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
| | - Marvin Bentley
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
| | - Kevin D Thorsen
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
| | - Ting Wang
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
| | - Lauren Foltz
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
| | - Viola Oorschot
- the Cell Microscopy Center, Department of Cell Biology, University Medical Center Utrecht, AZU Room H02.313, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Judith Klumperman
- the Cell Microscopy Center, Department of Cell Biology, University Medical Center Utrecht, AZU Room H02.313, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Jesse C Hay
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
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Karim S, Aronsson H. The puzzle of chloroplast vesicle transport - involvement of GTPases. FRONTIERS IN PLANT SCIENCE 2014; 5:472. [PMID: 25295043 PMCID: PMC4171996 DOI: 10.3389/fpls.2014.00472] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Accepted: 08/28/2014] [Indexed: 05/04/2023]
Abstract
In the cytosol of plant cells vesicle transport occurs via secretory pathways among the endoplasmic reticulum network, Golgi bodies, secretory granules, endosome, and plasma membrane. Three systems transfer lipids, proteins and other important molecules through aqueous spaces to membrane-enclosed compartments, via vesicles that bud from donor membranes, being coated and uncoated before tethered and fused with acceptor membranes. In addition, molecular, biochemical and ultrastructural evidence indicates presence of a vesicle transport system in chloroplasts. Little is known about the protein components of this system. However, as chloroplasts harbor the photosynthetic apparatus that ultimately supports most organisms on the planet, close attention to their pathways is warranted. This may also reveal novel diversification and/or distinct solutions to the problems posed by the targeted intra-cellular trafficking of important molecules. To date two homologs to well-known yeast cytosolic vesicle transport proteins, CPSAR1 and CPRabA5e (CP, chloroplast localized), have been shown to have roles in chloroplast vesicle transport, both being GTPases. Bioinformatic data indicate that several homologs of cytosolic vesicle transport system components are putatively chloroplast-localized and in addition other proteins have been implicated to participate in chloroplast vesicle transport, including vesicle-inducing protein in plastids 1, thylakoid formation 1, snowy cotyledon 2/cotyledon chloroplast biogenesis factor, curvature thylakoid 1 proteins, and a dynamin like GTPase FZO-like protein. Several putative potential cargo proteins have also been identified, including building blocks of the photosynthetic apparatus. Here we discuss details of the largely unknown putative chloroplast vesicle transport system, focusing on GTPase-related components.
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Affiliation(s)
| | - Henrik Aronsson
- *Correspondence: Henrik Aronsson, Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 405 30 Gothenburg, Sweden e-mail:
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15
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Yu S, Liang Y. A trapper keeper for TRAPP, its structures and functions. Cell Mol Life Sci 2012; 69:3933-44. [PMID: 22669257 PMCID: PMC11114727 DOI: 10.1007/s00018-012-1024-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/20/2012] [Accepted: 05/02/2012] [Indexed: 12/22/2022]
Abstract
During biosynthesis many membrane and secreted proteins are transported from the endoplasmic reticulum, through the Golgi and on to the plasma membrane in small transport vesicles. These transport vesicles have to undergo budding, movement, tethering, docking, and fusion at each organelle of the biosynthetic pathway. The transport protein particle (TRAPP) complex was initially identified as the tethering factor for endoplasmic reticulum (ER)-derived COPII vesicles, but the functions of TRAPP may extend to other areas of biology. Three forms of TRAPP complexes have been discovered to date, and recent advances in research have provided new insights on the structures and functions of TRAPP. Here we provide a comprehensive review of the recent findings in TRAPP biology.
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Affiliation(s)
- Sidney Yu
- School of Biomedical Sciences and Epithelial Cell Biology Research Center, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, People's Republic of China,
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TRAPPC9 mediates the interaction between p150 and COPII vesicles at the target membrane. PLoS One 2012; 7:e29995. [PMID: 22279557 PMCID: PMC3261171 DOI: 10.1371/journal.pone.0029995] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 12/07/2011] [Indexed: 11/19/2022] Open
Abstract
Background The transport of endoplasmic reticulum (ER)-derived COPII vesicles toward the ER-Golgi intermediate compartment (ERGIC) requires cytoplasmic dynein and is dependent on microtubules. p150Glued, a subunit of dynactin, has been implicated in the transport of COPII vesicles via its interaction with COPII coat components Sec23 and Sec24. However, whether and how COPII vesicle tether, TRAPP (Transport protein particle), plays a role in the interaction between COPII vesicles and microtubules is currently unknown. Principle Findings We address the functional relationship between COPII tether TRAPP and dynactin. Overexpressed TRAPP subunits interfered with microtubule architecture by competing p150Glued away from the MTOC. TRAPP subunit TRAPPC9 bound directly to p150Glued via the same carboxyl terminal domain of p150Glued that binds Sec23 and Sec24. TRAPPC9 also inhibited the interaction between p150Glued and Sec23/Sec24 both in vitro and in vivo, suggesting that TRAPPC9 serves to uncouple p150Glued from the COPII coat, and to relay the vesicle-dynactin interaction at the target membrane. Conclusions These findings provide a new perspective on the function of TRAPP as an adaptor between the ERGIC membrane and dynactin. By preserving the connection between dynactin and the tethered and/or fused vesicles, TRAPP allows nascent ERGIC to continue the movement along the microtubules as they mature into the cis-Golgi.
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Abstract
When a coated transport vesicle docks with its target membrane, the coat proteins and docking machinery must be released before the membranes can fuse. A recent paper shows how this disassembly is triggered at precisely the right time.
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Affiliation(s)
- Elizabeth Conibear
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada, V5Z 4H4.
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