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Abstract
Purpose of Review We provide an overview of the current knowledge on cytochrome P450-mediated metabolism organized as metabolons and factors that facilitate their stabilization. Essential parameters will be discussed including those that are commonly disregarded using the dhurrin metabolon from Sorghum bicolor as a case study. Recent Findings Sessile plants control their metabolism to prioritize their resources between growth and development, or defense. This requires fine-tuned complex dynamic regulation of the metabolic networks involved. Within the recent years, numerous studies point to the formation of dynamic metabolons playing a major role in controlling the metabolic fluxes within such networks. Summary We propose that P450s and their partners interact and associate dynamically with POR, which acts as a charging station possibly in concert with Cytb5. Solvent environment, lipid composition, and non-catalytic proteins guide metabolon formation and thereby activity, which have important implications for synthetic biology approaches aiming to produce high-value specialized metabolites in heterologous hosts.
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Affiliation(s)
- Jean-Etienne Bassard
- Plant Biochemistry Laboratory, Center for Synthetic Biology, VILLUM Research Center “Plant Plasticity,” Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen Denmark
| | - Birger Lindberg Møller
- Plant Biochemistry Laboratory, Center for Synthetic Biology, VILLUM Research Center “Plant Plasticity,” Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen Denmark
- Carlsberg Research Laboratory, Gamle Carlsberg Vej 10, DK-1799 Copenhagen V, Denmark
| | - Tomas Laursen
- Plant Biochemistry Laboratory, Center for Synthetic Biology, VILLUM Research Center “Plant Plasticity,” Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen Denmark
- Feedstocks Division, Joint BioEnergy Institute, Emeryville, CA 94608 USA
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102
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Brunkard JO, Zambryski PC. Plasmodesmata enable multicellularity: new insights into their evolution, biogenesis, and functions in development and immunity. CURRENT OPINION IN PLANT BIOLOGY 2017; 35:76-83. [PMID: 27889635 DOI: 10.1016/j.pbi.2016.11.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/04/2016] [Accepted: 11/08/2016] [Indexed: 05/19/2023]
Abstract
Plant cells are connected by plasmodesmata (PD), cytosolic bridges that allow molecules to freely move across the cell wall. Recently resolved relationships among land plants and their algal relatives reveal that land plants evolved PD independently from algae. Proteomic and genetic screens illuminate new dimensions of the structural and regulatory pathways that control PD biogenesis. Biochemical studies demonstrate that immunological signals induce systemic defenses by moving from diseased cells through PD; subsequently, PD transport is restricted to quarantine diseased cells. Here, we review our expanding knowledge of the roles of PD in plant development, physiology, and immunity.
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Affiliation(s)
- Jacob O Brunkard
- Plant Gene Expression Center, USDA Agricultural Research Service, 800 Buchanan Street, Albany, CA 94710, USA
| | - Patricia C Zambryski
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
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103
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Endoplasmic Reticulum - Plasma Membrane Crosstalk Mediated by the Extended Synaptotagmins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:83-93. [PMID: 28815523 DOI: 10.1007/978-981-10-4567-7_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The endoplasmic reticulum (ER) possesses multiplicity of functions including protein synthesis, membrane lipid biogenesis, and Ca2+ storage and has broad localization throughout the cell. While the ER and most other membranous organelles are highly interconnected via vesicular traffic that relies on membrane budding and fusion reactions, the ER forms direct contacts with virtually all other membranous organelles, including the plasma membrane (PM), without membrane fusion. Growing evidence suggests that these contacts play major roles in cellular physiology, including the regulation of Ca2+ homeostasis and signaling and control of cellular lipid homeostasis. Extended synaptotagmins (E-Syts) are evolutionarily conserved family of ER-anchored proteins that tether the ER to the PM in PM PI(4,5)P2-dependent and cytosolic Ca2+-regulated manner. In addition, E-Syts possess a cytosolically exposed lipid-harboring module that confers the ability to transfer/exchange glycerolipids between the ER and the PM at E-Syts-mediated ER-PM contacts. In this chapter, the functions of ER-PM contacts and their role in non-vesicular lipid transport with special emphasis on the crosstalk between the two bilayers mediated by E-Syts will be discussed.
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104
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Griffing LR, Lin C, Perico C, White RR, Sparkes I. Plant ER geometry and dynamics: biophysical and cytoskeletal control during growth and biotic response. PROTOPLASMA 2017; 254:43-56. [PMID: 26862751 PMCID: PMC5216105 DOI: 10.1007/s00709-016-0945-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 01/13/2016] [Indexed: 05/20/2023]
Abstract
The endoplasmic reticulum (ER) is an intricate and dynamic network of membrane tubules and cisternae. In plant cells, the ER 'web' pervades the cortex and endoplasm and is continuous with adjacent cells as it passes through plasmodesmata. It is therefore the largest membranous organelle in plant cells. It performs essential functions including protein and lipid synthesis, and its morphology and movement are linked to cellular function. An emerging trend is that organelles can no longer be seen as discrete membrane-bound compartments, since they can physically interact and 'communicate' with one another. The ER may form a connecting central role in this process. This review tackles our current understanding and quantification of ER dynamics and how these change under a variety of biotic and developmental cues.
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Affiliation(s)
- Lawrence R Griffing
- Biology Department, Texas A&M University, 3258 TAMU, College Station, TX, 77843, USA
| | - Congping Lin
- Mathematics Research Institute, Harrison Building, University of Exeter, Exeter, EX4 4QF, UK
| | - Chiara Perico
- Biosciences, CLES, Exeter University, Geoffrey Pope Building, Stocker Rd, Exeter, EX4 4QD, UK
| | - Rhiannon R White
- Biosciences, CLES, Exeter University, Geoffrey Pope Building, Stocker Rd, Exeter, EX4 4QD, UK
| | - Imogen Sparkes
- Biosciences, CLES, Exeter University, Geoffrey Pope Building, Stocker Rd, Exeter, EX4 4QD, UK.
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105
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DeBlasio SL, Johnson RS, MacCoss MJ, Gray SM, Cilia M. Model System-Guided Protein Interaction Mapping for Virus Isolated from Phloem Tissue. J Proteome Res 2016; 15:4601-4611. [DOI: 10.1021/acs.jproteome.6b00715] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stacy L. DeBlasio
- Agricultural
Research Service, USDA, Ithaca, New York 14853, United States
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, United States
| | - Richard S. Johnson
- Department
of Genome Sciences, University of Washington, Seattle Washington 98109, United States
| | - Michael J. MacCoss
- Department
of Genome Sciences, University of Washington, Seattle Washington 98109, United States
| | - Stewart M. Gray
- Agricultural
Research Service, USDA, Ithaca, New York 14853, United States
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York 14853, United States
| | - Michelle Cilia
- Agricultural
Research Service, USDA, Ithaca, New York 14853, United States
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, United States
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York 14853, United States
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106
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Siao W, Wang P, Voigt B, Hussey PJ, Baluska F. Arabidopsis SYT1 maintains stability of cortical endoplasmic reticulum networks and VAP27-1-enriched endoplasmic reticulum-plasma membrane contact sites. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:6161-6171. [PMID: 27811083 PMCID: PMC5100027 DOI: 10.1093/jxb/erw381] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Arabidopsis synaptotagmin 1 (SYT1) is localized on the endoplasmic reticulum-plasma membrane (ER-PM) contact sites in leaf and root cells. The ER-PM localization of Arabidopsis SYT1 resembles that of the extended synaptotagmins (E-SYTs) in animal cells. In mammals, E-SYTs have been shown to regulate calcium signaling, lipid transfer, and endocytosis. Arabidopsis SYT1 was reported to be essential for maintaining cell integrity and virus movement. This study provides detailed insight into the subcellular localization of SYT1 and VAP27-1, another ER-PM-tethering protein. SYT1 and VAP27-1 were shown to be localized on distinct ER-PM contact sites. The VAP27-1-enriched ER-PM contact sites (V-EPCSs) were always in contact with the SYT1-enriched ER-PM contact sites (S-EPCSs). The V-EPCSs still existed in the leaf epidermal cells of the SYT1 null mutant; however, they were less stable than those in the wild type. The polygonal networks of cortical ER disassembled and the mobility of VAP27-1 protein on the ER-PM contact sites increased in leaf cells of the SYT1 null mutant. These results suggest that SYT1 is responsible for stabilizing the ER network and V-EPCSs.
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Affiliation(s)
- Wei Siao
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany
| | - Pengwei Wang
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Boris Voigt
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany
| | - Patrick J Hussey
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Frantisek Baluska
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany
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107
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Ho CM, Paciorek T, Abrash E, Bergmann D. Modulators of Stomatal Lineage Signal Transduction Alter Membrane Contact Sites and Reveal Specialization among ERECTA Kinases. Dev Cell 2016; 38:345-57. [DOI: 10.1016/j.devcel.2016.07.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 05/18/2016] [Accepted: 07/21/2016] [Indexed: 11/29/2022]
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108
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Tremblay MG, Moss T. Loss of all 3 Extended Synaptotagmins does not affect normal mouse development, viability or fertility. Cell Cycle 2016; 15:2360-6. [PMID: 27399837 PMCID: PMC5004701 DOI: 10.1080/15384101.2016.1203494] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
The extended synaptotagmins, E-Syt1, 2 and 3, are multiple C2 domain membrane proteins that are tethered to the endoplasmic reticulum and interact in a calcium dependent manner with plasma membrane phospholipids to form endoplasmic reticulum - plasma membrane junctions. These junctions have been implicated in the exchange of phospholipids between the 2 organelles. The E-Syts have further been implicated in receptor signaling and endocytosis and can interact directly with fibroblast growth factor and other cell surface receptors. Despite these multiple functions, the search for a requirement in vivo has been elusive. Most recently, we found that the genes for E-Syt2 and 3 could be inactivated without effect on mouse development, viability, fertility or morphology. We have now created insertion and deletion mutations in the last of the mouse E-Syt genes. We show that E-Syt1 is specifically expressed throughout the embryonic skeleton during the early stages of chrondrogenesis in a pattern quite distinct from that of E-Syt2 or 3. Despite this, E-Syt1 is also not required for mouse development and propagation. We further show that even the combined inactivation of all 3 E-Syt genes has no effect on mouse viability or fertility in the laboratory. However, this inactivation induces an enhancement in the expression of the genes encoding Orp5/8, Orai1, STIM1 and TMEM110, endoplasmic reticulum - plasma membrane junction proteins that potentially could compensate for E-Syt loss. Given the multiple functions suggested for the E-Syts and their evolutionary conservation, our unexpected findings suggest that they may only provide a survival advantage under specific conditions that have as yet to be identified.
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Affiliation(s)
- Michel G Tremblay
- a Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Center , Quebec , QC , Canada.,b Department of Molecular Biology , Medical Biochemistry and Pathology, Faculty of Medicine, Laval University , Québec , QC , Canada
| | - Tom Moss
- a Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Center , Quebec , QC , Canada.,b Department of Molecular Biology , Medical Biochemistry and Pathology, Faculty of Medicine, Laval University , Québec , QC , Canada
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109
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Sclip A, Bacaj T, Giam LR, Südhof TC. Extended Synaptotagmin (ESyt) Triple Knock-Out Mice Are Viable and Fertile without Obvious Endoplasmic Reticulum Dysfunction. PLoS One 2016; 11:e0158295. [PMID: 27348751 PMCID: PMC4922586 DOI: 10.1371/journal.pone.0158295] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/13/2016] [Indexed: 01/15/2023] Open
Abstract
Extended synaptotagmins (ESyts) are endoplasmic reticulum (ER) proteins composed of an N-terminal transmembrane region, a central SMP-domain, and five (ESyt1) or three C-terminal cytoplasmic C2-domains (ESyt2 and ESyt3). ESyts bind phospholipids in a Ca2+-dependent manner via their C2-domains, are localized to ER-plasma membrane contact sites, and may catalyze lipid exchange between the plasma membrane and the ER via their SMP-domains. However, the overall function of ESyts has remained enigmatic. Here, we generated triple constitutive and conditional knock-out mice that lack all three ESyt isoforms; in addition, we produced knock-in mice that express mutant ESyt1 or ESyt2 carrying inactivating substitutions in the Ca2+-binding sites of their C2A-domains. Strikingly, all ESyt mutant mice, even those lacking all ESyts, were apparently normal and survived and bred in a manner indistinguishable from control mice. ESyt mutant mice displayed no major changes in brain morphology or synaptic protein composition, and exhibited no large alterations in stress responses. Thus, in mice ESyts do not perform an essential role in basic cellular functions, suggesting that these highly conserved proteins may perform a specialized role that may manifest only during specific, as yet untested challenges.
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Affiliation(s)
- Alessandra Sclip
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305–5453, United States of America
- Howard Hughes Medical Institute, Stanford University Medical School, 265 Campus Drive, Stanford, CA, United States of America
| | - Taulant Bacaj
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305–5453, United States of America
| | - Louise R. Giam
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305–5453, United States of America
| | - Thomas C. Südhof
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305–5453, United States of America
- Howard Hughes Medical Institute, Stanford University Medical School, 265 Campus Drive, Stanford, CA, United States of America
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110
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Pérez-Sancho J, Tilsner J, Samuels AL, Botella MA, Bayer EM, Rosado A. Stitching Organelles: Organization and Function of Specialized Membrane Contact Sites in Plants. Trends Cell Biol 2016; 26:705-717. [PMID: 27318776 DOI: 10.1016/j.tcb.2016.05.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/17/2016] [Accepted: 05/20/2016] [Indexed: 01/05/2023]
Abstract
The coordination of multiple metabolic activities in plants relies on an interorganelle communication network established through membrane contact sites (MCS). The MCS are maintained in transient or durable configurations by tethering structures which keep the two membranes in close proximity, and create chemical microdomains that allow localized and targeted exchange of small molecules and possibly proteins. The past few years have witnessed a dramatic increase in our understanding of the structural and molecular organization of plant interorganelle MCS, and their crucial roles in plant specialized functions including stress responses, cell to cell communication, and lipid transport. In this review we summarize recent advances in understanding the molecular components, structural organization, and functions of different plant-specific MCS architectures.
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Affiliation(s)
- Jessica Pérez-Sancho
- Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, 29071 Malaga, Spain; Department of Botany, Faculty of Science, University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Jens Tilsner
- Biomedical Sciences Research Complex, University of St Andrews, BMS Building, North Haugh, St Andrews, Fife KY16 9ST, UK; Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - A Lacey Samuels
- Department of Botany, Faculty of Science, University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Miguel A Botella
- Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, 29071 Malaga, Spain
| | - Emmanuelle M Bayer
- Laboratory of Membrane Biogenesis (LBM), Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche 5200, University of Bordeaux, 71 Avenue Edouard Bourlaux, 33883 Villenave d'Ornon CEDEX, France
| | - Abel Rosado
- Department of Botany, Faculty of Science, University of British Columbia, Vancouver V6T 1Z4, Canada.
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111
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Kim H, Kwon H, Kim S, Kim MK, Botella MA, Yun HS, Kwon C. Synaptotagmin 1 Negatively Controls the Two Distinct Immune Secretory Pathways to Powdery Mildew Fungi in Arabidopsis. PLANT & CELL PHYSIOLOGY 2016; 57:1133-41. [PMID: 27016097 DOI: 10.1093/pcp/pcw061] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/18/2016] [Indexed: 05/23/2023]
Abstract
PEN1, one of the plasma membrane (PM) syntaxins, comprises an immune exocytic pathway by forming the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex with SNAP33 and VAMP721/722 in plants. Although this secretory pathway is also involved in plant growth and development, how plants control their exocytic activity is as yet poorly understood. Since constitutive PEN1 cycling between the PM and endocytosed vesicles is critical for its immune activity, we studied here the relationship of PEN1 to synaptotagmin 1 (SYT1) that is known to regulate endocytosis at the PM. Interestingly, syt1 plants showed enhanced disease resistance to the Arabidopsis-adapted Golovinomyces orontii fungus, and elevated protein but not transcript levels of PEN1 Calcium-dependent promotion of PEN1-SYT1 interaction suggests that SYT1 controls defense activities of the PEN1-associated secretory pathway by post-translationally modulating PEN1. Increased PEN1-SYT1 interaction and inhibited PEN1 SNARE complex induction by G. orontii additionally suggest that the adaption of phytopathogens to host plants might partly result from effective suppression of the PEN1-related secretory pathway. Further genetic analyses revealed that SYT1 also regulates the atypical peroxisomal myrosinase PEN2-associated secretory pathway.
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Affiliation(s)
- Hyeran Kim
- Max-Planck-Institut für Züchtungsforschung, Department of Plant Microbe Interactions, Carl-von-Linné-Weg 10, D-50829 Köln, Germany Center for Genome Engineering, Institute for Basic Science, Daejeon 305-811, Korea These authors contributed equally to this work.
| | - Hyeokjin Kwon
- Department of Molecular Biology, Dankook University, Yongin 448-701, Korea These authors contributed equally to this work
| | - Soohong Kim
- Department of Molecular Biology, Dankook University, Yongin 448-701, Korea
| | - Mi Kyung Kim
- Department of Molecular Biology, Dankook University, Yongin 448-701, Korea
| | - Miguel A Botella
- Departamento de Biologia Molecular y Bioquimica, Universidad de Malaga, 29071 Malaga, Spain
| | - Hye Sup Yun
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
| | - Chian Kwon
- Department of Molecular Biology, Dankook University, Yongin 448-701, Korea
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112
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Wang P, Richardson C, Hawkins TJ, Sparkes I, Hawes C, Hussey PJ. Plant VAP27 proteins: domain characterization, intracellular localization and role in plant development. THE NEW PHYTOLOGIST 2016; 210:1311-26. [PMID: 27159525 DOI: 10.1111/nph.13857] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 12/14/2015] [Indexed: 05/24/2023]
Abstract
The endoplasmic reticulum (ER) is connected to the plasma membrane (PM) through the plant-specific NETWORKED protein, NET3C, and phylogenetically conserved vesicle-associated membrane protein-associated proteins (VAPs). Ten VAP homologues (VAP27-1 to 27-10) can be identified in the Arabidopsis genome and can be divided into three clades. Representative members from each clade were tagged with fluorescent protein and expressed in Nicotiana benthamiana. Proteins from clades I and III localized to the ER as well as to ER/PM contact sites (EPCSs), whereas proteins from clade II were found only at the PM. Some of the VAP27-labelled EPCSs localized to plasmodesmata, and we show that the mobility of VAP27 at EPCSs is influenced by the cell wall. EPCSs closely associate with the cytoskeleton, but their structure is unaffected when the cytoskeleton is removed. VAP27-labelled EPCSs are found in most cell types in Arabidopsis, with the exception of cells in early trichome development. Arabidopsis plants expressing VAP27-GFP fusions exhibit pleiotropic phenotypes, including defects in root hair morphogenesis. A similar effect is also observed in plants expressing VAP27 RNAi. Taken together, these data indicate that VAP27 proteins used at EPCSs are essential for normal ER-cytoskeleton interaction and for plant development.
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Affiliation(s)
- Pengwei Wang
- School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Christine Richardson
- School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Timothy J Hawkins
- School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Imogen Sparkes
- College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Chris Hawes
- Department of Biological and Biomedical Sciences, Oxford Brookes University, Gipsy Lane, Oxford, OX3 0BP, UK
| | - Patrick J Hussey
- School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK
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113
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Gallo A, Vannier C, Galli T. Endoplasmic Reticulum-Plasma Membrane Associations:Structures and Functions. Annu Rev Cell Dev Biol 2016; 32:279-301. [PMID: 27298092 DOI: 10.1146/annurev-cellbio-111315-125024] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Inside eukaryotic cells, membrane contact sites (MCSs), regions where two membrane-bound organelles are apposed at less than 30 nm, generate regions of important lipid and calcium exchange. This review principally focuses on the structure and the function of MCSs between the endoplasmic reticulum (ER) and the plasma membrane (PM). Here we describe how tethering structures form and maintain these junctions and, in some instances, participate in their function. We then discuss recent insights into the mechanisms by which specific classes of proteins mediate nonvesicular lipid exchange between the ER and PM and how such phenomena, already known to be crucial for maintaining organelle identity, are also emerging as regulators of cell growth and development.
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Affiliation(s)
- Alessandra Gallo
- Membrane Traffic in Health & Disease Group (INSERM ERL U950), F-75013 Paris, France;
| | - Christian Vannier
- Membrane Traffic in Health & Disease Group (INSERM ERL U950), F-75013 Paris, France;
| | - Thierry Galli
- Membrane Traffic in Health & Disease Group (INSERM ERL U950), F-75013 Paris, France;
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114
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Control of plasma membrane lipid homeostasis by the extended synaptotagmins. Nat Cell Biol 2016; 18:504-15. [PMID: 27065097 PMCID: PMC4848133 DOI: 10.1038/ncb3339] [Citation(s) in RCA: 172] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 03/11/2016] [Indexed: 02/08/2023]
Abstract
Acute metabolic changes of plasma membrane (PM) lipids, such as those mediating signaling reactions, are rapidly compensated by homeostatic responses whose molecular basis is poorly understood. Here we show that the Extended-Synaptotagmins (E-Syts), ER proteins which function as PI(4,5)P2 and Ca2+-regulated tethers to the PM, participate in these responses. E-Syts transfer glycerolipids between bilayers in vitro and such transfer requires Ca2+ and their SMP domain, a lipid-harboring module. Genome edited cells lacking E-Syts do not exhibit abnormalities in the major glycerolipids at rest, but display enhanced and sustained accumulation of PM diacylglycerol (DAG) upon PI(4,5)P2 hydrolysis by PLC activation, which can be rescued by expression of E-Syt1, but not by mutant E-Syt1 lacking the SMP domain. The formation of E-Syts-dependent ER-PM tethers in response to stimuli that cleave PI(4,5)P2 and elevate Ca2+ may help reverse accumulation of DAG in the PM by transferring it to the ER for metabolic recycling.
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115
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Yuan C, Lazarowitz SG, Citovsky V. Identification of a Functional Plasmodesmal Localization Signal in a Plant Viral Cell-To-Cell-Movement Protein. mBio 2016; 7:e02052-15. [PMID: 26787834 PMCID: PMC4725018 DOI: 10.1128/mbio.02052-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 12/07/2015] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Our fundamental knowledge of the protein-sorting pathways required for plant cell-to-cell trafficking and communication via the intercellular connections termed plasmodesmata has been severely limited by the paucity of plasmodesmal targeting sequences that have been identified to date. To address this limitation, we have identified the plasmodesmal localization signal (PLS) in the Tobacco mosaic virus (TMV) cell-to-cell-movement protein (MP), which has emerged as the paradigm for dissecting the molecular details of cell-to-cell transport through plasmodesmata. We report here the identification of a bona fide functional TMV MP PLS, which encompasses amino acid residues between positions 1 and 50, with residues Val-4 and Phe-14 potentially representing critical sites for PLS function that most likely affect protein conformation or protein interactions. We then demonstrated that this PLS is both necessary and sufficient for protein targeting to plasmodesmata. Importantly, as TMV MP traffics to plasmodesmata by a mechanism that is distinct from those of the three plant cell proteins in which PLSs have been reported, our findings provide important new insights to expand our understanding of protein-sorting pathways to plasmodesmata. IMPORTANCE The science of virology began with the discovery of Tobacco mosaic virus (TMV). Since then, TMV has served as an experimental and conceptual model for studies of viruses and dissection of virus-host interactions. Indeed, the TMV cell-to-cell-movement protein (MP) has emerged as the paradigm for dissecting the molecular details of cell-to-cell transport through the plant intercellular connections termed plasmodesmata. However, one of the most fundamental and key functional features of TMV MP, its putative plasmodesmal localization signal (PLS), has not been identified. Here, we fill this gap in our knowledge and identify the TMV MP PLS.
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Affiliation(s)
- Cheng Yuan
- Department of Biochemistry and Cell Biology, State University of New York at Stony Brook, Stony Brook, New York, USA
| | - Sondra G Lazarowitz
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, USA
| | - Vitaly Citovsky
- Department of Biochemistry and Cell Biology, State University of New York at Stony Brook, Stony Brook, New York, USA
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Kriechbaumer V, Botchway SW, Slade SE, Knox K, Frigerio L, Oparka K, Hawes C. Reticulomics: Protein-Protein Interaction Studies with Two Plasmodesmata-Localized Reticulon Family Proteins Identify Binding Partners Enriched at Plasmodesmata, Endoplasmic Reticulum, and the Plasma Membrane. PLANT PHYSIOLOGY 2015; 169:1933-45. [PMID: 26353761 PMCID: PMC4634090 DOI: 10.1104/pp.15.01153] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 09/08/2015] [Indexed: 05/19/2023]
Abstract
The endoplasmic reticulum (ER) is a ubiquitous organelle that plays roles in secretory protein production, folding, quality control, and lipid biosynthesis. The cortical ER in plants is pleomorphic and structured as a tubular network capable of morphing into flat cisternae, mainly at three-way junctions, and back to tubules. Plant reticulon family proteins (RTNLB) tubulate the ER by dimerization and oligomerization, creating localized ER membrane tensions that result in membrane curvature. Some RTNLB ER-shaping proteins are present in the plasmodesmata (PD) proteome and may contribute to the formation of the desmotubule, the axial ER-derived structure that traverses primary PD. Here, we investigate the binding partners of two PD-resident reticulon proteins, RTNLB3 and RTNLB6, that are located in primary PD at cytokinesis in tobacco (Nicotiana tabacum). Coimmunoprecipitation of green fluorescent protein-tagged RTNLB3 and RTNLB6 followed by mass spectrometry detected a high percentage of known PD-localized proteins as well as plasma membrane proteins with putative membrane-anchoring roles. Förster resonance energy transfer by fluorescence lifetime imaging microscopy assays revealed a highly significant interaction of the detected PD proteins with the bait RTNLB proteins. Our data suggest that RTNLB proteins, in addition to a role in ER modeling, may play important roles in linking the cortical ER to the plasma membrane.
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Affiliation(s)
- Verena Kriechbaumer
- Plant Cell Biology, Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom (V.K., C.H.);Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0QX, United Kingdom (S.W.B.);Warwickshire Private Hospital (WPH) Proteomics Facility Research Technology Platform (S.E.S.) and School of Life Sciences (S.E.S., L.F.), University of Warwick, Coventry CV4 7AL, United Kingdom; andInstitute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom (K.K., K.O.)
| | - Stanley W Botchway
- Plant Cell Biology, Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom (V.K., C.H.);Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0QX, United Kingdom (S.W.B.);Warwickshire Private Hospital (WPH) Proteomics Facility Research Technology Platform (S.E.S.) and School of Life Sciences (S.E.S., L.F.), University of Warwick, Coventry CV4 7AL, United Kingdom; andInstitute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom (K.K., K.O.)
| | - Susan E Slade
- Plant Cell Biology, Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom (V.K., C.H.);Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0QX, United Kingdom (S.W.B.);Warwickshire Private Hospital (WPH) Proteomics Facility Research Technology Platform (S.E.S.) and School of Life Sciences (S.E.S., L.F.), University of Warwick, Coventry CV4 7AL, United Kingdom; andInstitute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom (K.K., K.O.)
| | - Kirsten Knox
- Plant Cell Biology, Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom (V.K., C.H.);Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0QX, United Kingdom (S.W.B.);Warwickshire Private Hospital (WPH) Proteomics Facility Research Technology Platform (S.E.S.) and School of Life Sciences (S.E.S., L.F.), University of Warwick, Coventry CV4 7AL, United Kingdom; andInstitute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom (K.K., K.O.)
| | - Lorenzo Frigerio
- Plant Cell Biology, Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom (V.K., C.H.);Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0QX, United Kingdom (S.W.B.);Warwickshire Private Hospital (WPH) Proteomics Facility Research Technology Platform (S.E.S.) and School of Life Sciences (S.E.S., L.F.), University of Warwick, Coventry CV4 7AL, United Kingdom; andInstitute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom (K.K., K.O.)
| | - Karl Oparka
- Plant Cell Biology, Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom (V.K., C.H.);Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0QX, United Kingdom (S.W.B.);Warwickshire Private Hospital (WPH) Proteomics Facility Research Technology Platform (S.E.S.) and School of Life Sciences (S.E.S., L.F.), University of Warwick, Coventry CV4 7AL, United Kingdom; andInstitute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom (K.K., K.O.)
| | - Chris Hawes
- Plant Cell Biology, Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom (V.K., C.H.);Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0QX, United Kingdom (S.W.B.);Warwickshire Private Hospital (WPH) Proteomics Facility Research Technology Platform (S.E.S.) and School of Life Sciences (S.E.S., L.F.), University of Warwick, Coventry CV4 7AL, United Kingdom; andInstitute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom (K.K., K.O.)
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