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Xu F, Wu Z, Tan C, Liao Y, Wang Z, Chen K, Pan A. Fourier Ptychographic Microscopy 10 Years on: A Review. Cells 2024; 13:324. [PMID: 38391937 PMCID: PMC10887115 DOI: 10.3390/cells13040324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/31/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024] Open
Abstract
Fourier ptychographic microscopy (FPM) emerged as a prominent imaging technique in 2013, attracting significant interest due to its remarkable features such as precise phase retrieval, expansive field of view (FOV), and superior resolution. Over the past decade, FPM has become an essential tool in microscopy, with applications in metrology, scientific research, biomedicine, and inspection. This achievement arises from its ability to effectively address the persistent challenge of achieving a trade-off between FOV and resolution in imaging systems. It has a wide range of applications, including label-free imaging, drug screening, and digital pathology. In this comprehensive review, we present a concise overview of the fundamental principles of FPM and compare it with similar imaging techniques. In addition, we present a study on achieving colorization of restored photographs and enhancing the speed of FPM. Subsequently, we showcase several FPM applications utilizing the previously described technologies, with a specific focus on digital pathology, drug screening, and three-dimensional imaging. We thoroughly examine the benefits and challenges associated with integrating deep learning and FPM. To summarize, we express our own viewpoints on the technological progress of FPM and explore prospective avenues for its future developments.
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Affiliation(s)
- Fannuo Xu
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China; (F.X.); (Z.W.); (C.T.); (Y.L.); (Z.W.); (K.C.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zipei Wu
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China; (F.X.); (Z.W.); (C.T.); (Y.L.); (Z.W.); (K.C.)
- School of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Chao Tan
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China; (F.X.); (Z.W.); (C.T.); (Y.L.); (Z.W.); (K.C.)
- School of Electronics and Information Engineering, Sichuan University, Chengdu 610065, China
| | - Yizheng Liao
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China; (F.X.); (Z.W.); (C.T.); (Y.L.); (Z.W.); (K.C.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiping Wang
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China; (F.X.); (Z.W.); (C.T.); (Y.L.); (Z.W.); (K.C.)
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Keru Chen
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China; (F.X.); (Z.W.); (C.T.); (Y.L.); (Z.W.); (K.C.)
- School of Automation Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - An Pan
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China; (F.X.); (Z.W.); (C.T.); (Y.L.); (Z.W.); (K.C.)
- University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Gallo R, Rai AK, McIntyre ABR, Meyer K, Pelkmans L. DYRK3 enables secretory trafficking by maintaining the liquid-like state of ER exit sites. Dev Cell 2023; 58:1880-1897.e11. [PMID: 37643612 DOI: 10.1016/j.devcel.2023.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 02/16/2023] [Accepted: 08/01/2023] [Indexed: 08/31/2023]
Abstract
The dual-specificity kinase DYRK3 controls the formation and dissolution of multiple biomolecular condensates, regulating processes including stress recovery and mitotic progression. Here, we report that DYRK3 functionally interacts with proteins associated with endoplasmic reticulum (ER) exit sites (ERESs) and that inhibition of DYRK3 perturbs the organization of the ERES-Golgi interface and secretory trafficking. DYRK3-mediated regulation of ERES depends on the N-terminal intrinsically disordered region (IDR) of the peripheral membrane protein SEC16A, which co-phase separates with ERES components to form liquid-like condensates on the surface of the ER. By modulating the liquid-like properties of ERES, we show that their physical state is essential for functional cargo trafficking through the early secretory pathway. Our findings support a mechanism whereby phosphorylation by DYRK3 and its reversal by serine-threonine phosphatases regulate the material properties of ERES to create a favorable physicochemical environment for directional membrane traffic in eukaryotic cells.
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Affiliation(s)
- Raffaella Gallo
- Department of Molecular Life Sciences, University of Zurich, 8046 Zurich, Switzerland
| | - Arpan Kumar Rai
- Department of Molecular Life Sciences, University of Zurich, 8046 Zurich, Switzerland.
| | - Alexa B R McIntyre
- Department of Molecular Life Sciences, University of Zurich, 8046 Zurich, Switzerland
| | - Katrina Meyer
- Department of Molecular Life Sciences, University of Zurich, 8046 Zurich, Switzerland
| | - Lucas Pelkmans
- Department of Molecular Life Sciences, University of Zurich, 8046 Zurich, Switzerland.
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3
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Gao L, Cao J, Gong S, Hao N, Du Y, Wang C, Wu T. The COPII subunit CsSEC23 mediates fruit glossiness in cucumber. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:524-540. [PMID: 37460197 DOI: 10.1111/tpj.16389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 07/07/2023] [Indexed: 07/28/2023]
Abstract
To improve our understanding of the mechanism underlying cucumber glossiness regulation, a novel cucumber mutant with a glossy peel (Csgp) was identified. MutMap, genotyping, and gene editing results demonstrated that CsSEC23, which is the core component of COPII vesicles, mediates the glossiness of cucumber fruit peel. CsSEC23 is functionally conserved and located in the Golgi and endoplasmic reticulum. CsSEC23 could interact with CsSEC31, but this interaction was absent in the Csgp mutant, which decreased the efficiency of COPII vesicle transportation. Genes related to wax and cutin transport were upregulated in the Csgp mutant, and the cuticle structure of the Csgp-mutant peel became thinner. Moreover, the wax and cutin contents were also changed due to CsSEC23 mutation. Taken together, the results obtained from this study revealed that CsSEC23 mediates cucumber glossiness, and this mediating might be affected by COPII vesicle transportation.
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Affiliation(s)
- Luyao Gao
- College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops (vegetables, tea, etc.), Ministry of Agriculture and Rural Affairs of China, Changsha, 410128, China
- Yuelushan Lab, Changsha, 410128, China
| | - Jiajian Cao
- College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops (vegetables, tea, etc.), Ministry of Agriculture and Rural Affairs of China, Changsha, 410128, China
- Yuelushan Lab, Changsha, 410128, China
- Whampoa Innovation Research Institute, Hunan Agricultural University, Changsha, 410128, China
| | - Siyu Gong
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, 150030, China
| | - Ning Hao
- College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Laboratory of Plant Nutrition and Fertilizers, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan
| | - Yalin Du
- College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops (vegetables, tea, etc.), Ministry of Agriculture and Rural Affairs of China, Changsha, 410128, China
- Yuelushan Lab, Changsha, 410128, China
- Whampoa Innovation Research Institute, Hunan Agricultural University, Changsha, 410128, China
| | - Chunhua Wang
- College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops (vegetables, tea, etc.), Ministry of Agriculture and Rural Affairs of China, Changsha, 410128, China
- Yuelushan Lab, Changsha, 410128, China
- Whampoa Innovation Research Institute, Hunan Agricultural University, Changsha, 410128, China
| | - Tao Wu
- College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops (vegetables, tea, etc.), Ministry of Agriculture and Rural Affairs of China, Changsha, 410128, China
- Yuelushan Lab, Changsha, 410128, China
- Whampoa Innovation Research Institute, Hunan Agricultural University, Changsha, 410128, China
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4
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Kasberg W, Luong P, Hanna MG, Minushkin K, Tsao A, Shankar R, Block S, Audhya A. The Sar1 GTPase is dispensable for COPII-dependent cargo export from the ER. Cell Rep 2023; 42:112635. [PMID: 37300835 PMCID: PMC10592460 DOI: 10.1016/j.celrep.2023.112635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 04/21/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Coat protein complex II (COPII) plays an integral role in the packaging of secretory cargoes within membrane-enclosed transport carriers that leave the endoplasmic reticulum (ER) from discrete subdomains. Lipid bilayer remodeling necessary for this process is driven initially by membrane penetration mediated by the Sar1 GTPase and further stabilized by assembly of a multilayered complex of several COPII proteins. However, the relative contributions of these distinct factors to transport carrier formation and protein trafficking remain unclear. Here, we demonstrate that anterograde cargo transport from the ER continues in the absence of Sar1, although the efficiency of this process is dramatically reduced. Specifically, secretory cargoes are retained nearly five times longer at ER subdomains when Sar1 is depleted, but they ultimately remain capable of being translocated to the perinuclear region of cells. Taken together, our findings highlight alternative mechanisms by which COPII promotes transport carrier biogenesis.
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Affiliation(s)
- William Kasberg
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Peter Luong
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Michael G Hanna
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Kayla Minushkin
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Annabelle Tsao
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Raakhee Shankar
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Samuel Block
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA.
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5
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Van der Verren SE, Zanetti G. The small GTPase Sar1, control centre of COPII trafficking. FEBS Lett 2023; 597:865-882. [PMID: 36737236 DOI: 10.1002/1873-3468.14595] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023]
Abstract
Sar1 is a small GTPase of the ARF family. Upon exchange of GDP for GTP, Sar1 associates with the endoplasmic reticulum (ER) membrane and recruits COPII components, orchestrating cargo concentration and membrane deformation. Many aspects of the role of Sar1 and regulation of its GTP cycle remain unclear, especially as complexity increases in higher organisms that secrete a wider range of cargoes. This review focusses on the regulation of GTP hydrolysis and its role in coat assembly, as well as the mechanism of Sar1-induced membrane deformation and scission. Finally, we highlight the additional specialisation in higher eukaryotes and the outstanding questions on how Sar1 functions are orchestrated.
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Affiliation(s)
| | - Giulia Zanetti
- Institute of Structural and Molecular Biology, Birkbeck College London, UK
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6
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De Matteis MA, Venditti R. ER exit sites take the strain. EMBO J 2022; 41:e112349. [PMID: 36121033 PMCID: PMC9627663 DOI: 10.15252/embj.2022112349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 09/07/2022] [Indexed: 11/09/2022] Open
Abstract
Cells are able to adapt their growth to external mechanical strain. A recent study by Phuyal et al (2022) has shown that these responses depend on the heterodimerization of two small GTPases.
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Affiliation(s)
| | - Rossella Venditti
- Telethon Institute of Genetics and MedicinePozzuoliItaly
- University of Naples “Federico II”NaplesItaly
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7
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A tango for coats and membranes: New insights into ER-to-Golgi traffic. Cell Rep 2022; 38:110258. [DOI: 10.1016/j.celrep.2021.110258] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/17/2021] [Accepted: 12/21/2021] [Indexed: 12/30/2022] Open
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8
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Abstract
Export from the ER is COPII-dependent. However, there is disagreement on the nature of the cargo-containing carriers that exit the ER. Two new studies from Shomron et al. (2021. J. Cell Biol.https://doi.org/10.1083/jcb.201907224) and Weigel et al. (2021. Cell. https://doi.org/10.1016/j.cell.2021.03.035) present a new model, where COPII helps to select secretory cargo but does not coat the carriers leaving the ER.
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Affiliation(s)
- Santosh Phuyal
- Institute of Pathophysiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Hesso Farhan
- Institute of Pathophysiology, Medical University of Innsbruck, Innsbruck, Austria.,Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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9
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Speckner K, Stadler L, Weiss M. Unscrambling exit site patterns on the endoplasmic reticulum as a quenched demixing process. Biophys J 2021; 120:2532-2542. [PMID: 33932435 DOI: 10.1016/j.bpj.2021.04.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/31/2021] [Accepted: 04/19/2021] [Indexed: 11/19/2022] Open
Abstract
The endoplasmic reticulum (ER) is a vital organelle in mammalian cells with a complex morphology. Consisting of sheet-like cisternae in the cell center, the peripheral ER forms a vast tubular network on which a dispersed pattern of a few hundred specialized domains (ER exit sites (ERESs)) is maintained. Molecular details of cargo sorting and vesicle formation at individual ERESs, fueling the early secretory pathway, have been studied in some detail. The emergence of spatially extended ERES patterns, however, has remained poorly understood. Here, we show that these patterns are determined by the underlying ER morphology, suggesting ERESs to emerge from a demixing process that is quenched by the ER network topology. In particular, we observed fewer but larger ERESs when transforming the ER network to more sheet-like morphologies. In contrast, little to no changes with respect to native ERES patterns were observed when fragmenting the ER, indicating that hampering the diffusion-mediated coarse graining of domains is key for native ERES patterns. Model simulations support the notion of effective diffusion barriers impeding the coarse graining and maturation of ERES patterns. We speculate that tuning a simple demixing mechanism by the ER topology allows for a robust but flexible adaption of ERES patterns, ensuring a properly working early secretory pathway in a variety of conditions.
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Affiliation(s)
| | - Lorenz Stadler
- Experimental Physics I, University of Bayreuth, Bayreuth, Germany
| | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, Bayreuth, Germany.
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10
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Shomron O, Nevo-Yassaf I, Aviad T, Yaffe Y, Zahavi EE, Dukhovny A, Perlson E, Brodsky I, Yeheskel A, Pasmanik-Chor M, Mironov A, Beznoussenko GV, Mironov AA, Sklan EH, Patterson GH, Yonemura Y, Sannai M, Kaether C, Hirschberg K. COPII collar defines the boundary between ER and ER exit site and does not coat cargo containers. J Cell Biol 2021; 220:211990. [PMID: 33852719 PMCID: PMC8054201 DOI: 10.1083/jcb.201907224] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 01/14/2021] [Accepted: 03/11/2021] [Indexed: 12/13/2022] Open
Abstract
COPII and COPI mediate the formation of membrane vesicles translocating in opposite directions within the secretory pathway. Live-cell and electron microscopy revealed a novel mode of function for COPII during cargo export from the ER. COPII is recruited to membranes defining the boundary between the ER and ER exit sites, facilitating selective cargo concentration. Using direct observation of living cells, we monitored cargo selection processes, accumulation, and fission of COPII-free ERES membranes. CRISPR/Cas12a tagging, the RUSH system, and pharmaceutical and genetic perturbations of ER-Golgi transport demonstrated that the COPII coat remains bound to the ER–ERES boundary during protein export. Manipulation of the cargo-binding domain in COPII Sec24B prohibits cargo accumulation in ERES. These findings suggest a role for COPII in selecting and concentrating exported cargo rather than coating Golgi-bound carriers. These findings transform our understanding of coat proteins’ role in ER-to-Golgi transport.
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Affiliation(s)
- Olga Shomron
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Inbar Nevo-Yassaf
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Tamar Aviad
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Yakey Yaffe
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Eitan Erez Zahavi
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Anna Dukhovny
- Department of Clinical Immunology and Microbiology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Eran Perlson
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Ilya Brodsky
- Lomonosov Moscow State University, Andrey N. Belozersky Institute for Physico-Chemical Biology, Moscow, Russia
| | - Adva Yeheskel
- Bioinformatics Unit, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | - Metsada Pasmanik-Chor
- Bioinformatics Unit, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | - Anna Mironov
- Istituto Firc di Oncologia Molecolare, Fondazione Istituto Fondazione Italiana per la Ricerca sul Cancro di Oncologia Molecolare, Milan, Italy
| | - Galina V Beznoussenko
- Istituto Firc di Oncologia Molecolare, Fondazione Istituto Fondazione Italiana per la Ricerca sul Cancro di Oncologia Molecolare, Milan, Italy
| | - Alexander A Mironov
- Istituto Firc di Oncologia Molecolare, Fondazione Istituto Fondazione Italiana per la Ricerca sul Cancro di Oncologia Molecolare, Milan, Italy
| | - Ella H Sklan
- Department of Clinical Immunology and Microbiology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - George H Patterson
- Section on Biophotonics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Rockville, MD
| | - Yoji Yonemura
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | - Mara Sannai
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | | | - Koret Hirschberg
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
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11
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Weigel AV, Chang CL, Shtengel G, Xu CS, Hoffman DP, Freeman M, Iyer N, Aaron J, Khuon S, Bogovic J, Qiu W, Hess HF, Lippincott-Schwartz J. ER-to-Golgi protein delivery through an interwoven, tubular network extending from ER. Cell 2021; 184:2412-2429.e16. [PMID: 33852913 DOI: 10.1016/j.cell.2021.03.035] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 12/23/2020] [Accepted: 03/16/2021] [Indexed: 12/15/2022]
Abstract
Cellular versatility depends on accurate trafficking of diverse proteins to their organellar destinations. For the secretory pathway (followed by approximately 30% of all proteins), the physical nature of the vessel conducting the first portage (endoplasmic reticulum [ER] to Golgi apparatus) is unclear. We provide a dynamic 3D view of early secretory compartments in mammalian cells with isotropic resolution and precise protein localization using whole-cell, focused ion beam scanning electron microscopy with cryo-structured illumination microscopy and live-cell synchronized cargo release approaches. Rather than vesicles alone, the ER spawns an elaborate, interwoven tubular network of contiguous lipid bilayers (ER exit site) for protein export. This receptacle is capable of extending microns along microtubules while still connected to the ER by a thin neck. COPII localizes to this neck region and dynamically regulates cargo entry from the ER, while COPI acts more distally, escorting the detached, accelerating tubular entity on its way to joining the Golgi apparatus through microtubule-directed movement.
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Affiliation(s)
- Aubrey V Weigel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Chi-Lun Chang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Gleb Shtengel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - C Shan Xu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | | | - Melanie Freeman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Advanced Bioimaging Center, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Nirmala Iyer
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Jesse Aaron
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Satya Khuon
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - John Bogovic
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Wei Qiu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Harald F Hess
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
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12
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Abstract
The functions of coat protein complex II (COPII) coats in cargo packaging and the creation of vesicles at the endoplasmic reticulum are conserved in eukaryotic protein secretion. Standard COPII vesicles, however, cannot handle the secretion of metazoan-specific cargoes such as procollagens, apolipoproteins, and mucins. Metazoans have thus evolved modules centered on proteins like TANGO1 (transport and Golgi organization 1) to engage COPII coats and early secretory pathway membranes to engineer a novel mode of cargo export at the endoplasmic reticulum.
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Affiliation(s)
- I Raote
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain; ,
| | - V Malhotra
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain; , .,Universitat Pompeu Fabra (UPF), Barcelona 08002, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona 08010, Spain
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13
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Raote I, Chabanon M, Walani N, Arroyo M, Garcia-Parajo MF, Malhotra V, Campelo F. A physical mechanism of TANGO1-mediated bulky cargo export. eLife 2020; 9:e59426. [PMID: 33169667 PMCID: PMC7704110 DOI: 10.7554/elife.59426] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 11/09/2020] [Indexed: 01/08/2023] Open
Abstract
The endoplasmic reticulum (ER)-resident protein TANGO1 assembles into a ring around ER exit sites (ERES), and links procollagens in the ER lumen to COPII machinery, tethers, and ER-Golgi intermediate compartment (ERGIC) in the cytoplasm (Raote et al., 2018). Here, we present a theoretical approach to investigate the physical mechanisms of TANGO1 ring assembly and how COPII polymerization, membrane tension, and force facilitate the formation of a transport intermediate for procollagen export. Our results indicate that a TANGO1 ring, by acting as a linactant, stabilizes the open neck of a nascent COPII bud. Elongation of such a bud into a transport intermediate commensurate with bulky procollagens is then facilitated by two complementary mechanisms: (i) by relieving membrane tension, possibly by TANGO1-mediated fusion of retrograde ERGIC membranes and (ii) by force application. Altogether, our theoretical approach identifies key biophysical events in TANGO1-driven procollagen export.
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Affiliation(s)
- Ishier Raote
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
| | - Morgan Chabanon
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Politècnica de Catalunya-BarcelonaTechBarcelonaSpain
| | - Nikhil Walani
- Universitat Politècnica de Catalunya-BarcelonaTechBarcelonaSpain
| | - Marino Arroyo
- Universitat Politècnica de Catalunya-BarcelonaTechBarcelonaSpain
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Centre Internacional de Mètodes Numèrics en Enginyeria (CIMNE)BarcelonaSpain
| | - Maria F Garcia-Parajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and TechnologyBarcelonaSpain
- ICREABarcelonaSpain
| | - Vivek Malhotra
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
- ICREABarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Felix Campelo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and TechnologyBarcelonaSpain
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14
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Subramanian A, Capalbo A, Iyengar NR, Rizzo R, di Campli A, Di Martino R, Lo Monte M, Beccari AR, Yerudkar A, Del Vecchio C, Glielmo L, Turacchio G, Pirozzi M, Kim SG, Henklein P, Cancino J, Parashuraman S, Diviani D, Fanelli F, Sallese M, Luini A. Auto-regulation of Secretory Flux by Sensing and Responding to the Folded Cargo Protein Load in the Endoplasmic Reticulum. Cell 2020; 176:1461-1476.e23. [PMID: 30849374 DOI: 10.1016/j.cell.2019.01.035] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 08/30/2018] [Accepted: 01/23/2019] [Indexed: 11/19/2022]
Abstract
Maintaining the optimal performance of cell processes and organelles is the task of auto-regulatory systems. Here we describe an auto-regulatory device that helps to maintain homeostasis of the endoplasmic reticulum (ER) by adjusting the secretory flux to the cargo load. The cargo-recruiting subunit of the coatomer protein II (COPII) coat, Sec24, doubles as a sensor of folded cargo and, upon cargo binding, acts as a guanine nucleotide exchange factor to activate the signaling protein Gα12 at the ER exit sites (ERESs). This step, in turn, activates a complex signaling network that activates and coordinates the ER export machinery and attenuates proteins synthesis, thus preventing large fluctuations of folded and potentially active cargo that could be harmful to the cell or the organism. We call this mechanism AREX (autoregulation of ER export) and expect that its identification will aid our understanding of human physiology and diseases that develop from secretory dysfunction.
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Affiliation(s)
- Advait Subramanian
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy.
| | - Anita Capalbo
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Namrata Ravi Iyengar
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Riccardo Rizzo
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Antonella di Campli
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy; Department of Medical, Oral and Biotechnological Sciences and CeSI-MeT, Center for Research on Ageing and Translational Medicine, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Rosaria Di Martino
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Matteo Lo Monte
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Andrea R Beccari
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy; Dompé Farmaceutici SpA, Milan, Italy
| | - Amol Yerudkar
- Department of Engineering, Universitá degli Studi del Sannio, Benevento, Italy
| | - Carmen Del Vecchio
- Department of Engineering, Universitá degli Studi del Sannio, Benevento, Italy
| | - Luigi Glielmo
- Department of Engineering, Universitá degli Studi del Sannio, Benevento, Italy
| | - Gabriele Turacchio
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Marinella Pirozzi
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Sang Geon Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, South Korea
| | - Petra Henklein
- Institut fur Biochemie, Charite Universitätsmedizin, Berlin, Germany
| | - Jorge Cancino
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile
| | | | - Dario Diviani
- Université de Lausanne, Département de Pharmacologie et Toxicologie, Rue du Bugnon 27, 1011 Lausanne, Switzerland
| | - Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Michele Sallese
- Department of Medical, Oral and Biotechnological Sciences and CeSI-MeT, Center for Research on Ageing and Translational Medicine, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Alberto Luini
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy.
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15
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Giacomello E, Ronchi P, Pepperkok R. GM130 and p115 play a key role in the organisation of the early secretory pathway during skeletal muscle differentiation. J Cell Sci 2019; 132:jcs.222083. [DOI: 10.1242/jcs.222083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 12/20/2018] [Indexed: 12/24/2022] Open
Abstract
ABSTRACT
Skeletal muscle (SKM) differentiation is a highly regulated process leading to the formation of specialised cells with reorganised compartments and organelles, such as those of the early secretory pathway. During SKM differentiation the Golgi complex (GC) redistributes close to the nuclear envelope and in small distinct peripheral structures distributed throughout the myotube. Concurrently, GC elements closely associate with endoplasmic reticulum-exit sites (ERES). The mechanisms underlying this reorganisation and its relevance for SKM differentiation are poorly understood. Here, we show, by time-lapse imaging studies, that the changes in GC organisation involve GC fragmentation and redistribution of ERES with the formation of tightly associated GC–ERES units. We show that knockdown of GM130 (also known as GOLGA2) or p115 (also known as USO1), two regulators of the early secretory pathway, impairs GC and ERES reorganisation. This in turn results in inhibition of myotube fusion and M-cadherin (also known as CDH15) transport to the sarcolemma. Taken together, our data suggest that the correct reorganisation of the early secretory pathway components plays an important role in SKM differentiation and, thus, associated pathologies.
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Affiliation(s)
- Emiliana Giacomello
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, (EMBL), Meyerhofstraße 1, Heidelberg D-69117, Germany
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste 34149, Italy
| | - Paolo Ronchi
- Electron Microscopy Core Facility, Europen Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, Heidelberg D-69117, Germany
| | - Rainer Pepperkok
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, (EMBL), Meyerhofstraße 1, Heidelberg D-69117, Germany
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16
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Neumann A, Schindler M, Olofsson D, Wilhelmi I, Schürmann A, Heyd F. Genome-wide identification of alternative splicing events that regulate protein transport across the secretory pathway. J Cell Sci 2019; 132:jcs.230201. [DOI: 10.1242/jcs.230201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 03/09/2019] [Indexed: 01/05/2023] Open
Abstract
Alternative splicing (AS) strongly increases proteome diversity and functionality in eukaryotic cells. Protein secretion is a tightly-controlled process, especially in a tissue-specific and differentiation-dependent manner. While previous work has focussed on transcriptional and post-translational regulatory mechanisms, the impact of AS on the secretory pathway remains largely unexplored. Here we integrate a published screen for modulators of protein transport and RNA-Seq analyses to identify over 200 AS events as secretion regulators. We confirm that splicing events along all stages of the secretory pathway regulate the efficiency of membrane trafficking using Morpholinos and CRISPR/Cas9. We furthermore show that these events are highly tissue-specific and adapt the secretory pathway during T-cell activation and adipocyte differentiation. Our data substantially advance the understanding of AS functionality, add a new regulatory layer to a fundamental cell biological process and provide a resource of alternative isoforms that control the secretory pathway.
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Affiliation(s)
- Alexander Neumann
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Takustrasse 6, 14195 Berlin, Germany
| | - Magdalena Schindler
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Takustrasse 6, 14195 Berlin, Germany
| | - Didrik Olofsson
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Takustrasse 6, 14195 Berlin, Germany
| | - Ilka Wilhelmi
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbrücke (DIfE), 14558 Nuthetal, Germany
| | - Annette Schürmann
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbrücke (DIfE), 14558 Nuthetal, Germany
| | - Florian Heyd
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Takustrasse 6, 14195 Berlin, Germany
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17
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Farrugia MA, Puglielli L. Nε-lysine acetylation in the endoplasmic reticulum - a novel cellular mechanism that regulates proteostasis and autophagy. J Cell Sci 2018; 131:131/22/jcs221747. [PMID: 30446507 DOI: 10.1242/jcs.221747] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Protein post-translational modifications (PTMs) take many shapes, have many effects and are necessary for cellular homeostasis. One of these PTMs, Nε-lysine acetylation, was thought to occur only in the mitochondria, cytosol and nucleus, but this paradigm was challenged in the past decade with the discovery of lysine acetylation in the lumen of the endoplasmic reticulum (ER). This process is governed by the ER acetylation machinery: the cytosol:ER-lumen acetyl-CoA transporter AT-1 (also known as SLC33A1), and the ER-resident lysine acetyltransferases ATase1 and ATase2 (also known as NAT8B and NAT8, respectively). This Review summarizes the more recent biochemical, cellular and mouse model studies that underscore the importance of the ER acetylation process in maintaining protein homeostasis and autophagy within the secretory pathway, and its impact on developmental and age-associated diseases.
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Affiliation(s)
- Mark A Farrugia
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA.,Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Luigi Puglielli
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA .,Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA.,Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705, USA.,Geriatric Research Education Clinical Center, VA Medical Center, Madison, WI 53705, USA
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18
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Stadler L, Speckner K, Weiss M. Diffusion of Exit Sites on the Endoplasmic Reticulum: A Random Walk on a Shivering Backbone. Biophys J 2018; 115:1552-1560. [PMID: 30274831 PMCID: PMC6260206 DOI: 10.1016/j.bpj.2018.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/03/2018] [Accepted: 09/05/2018] [Indexed: 12/14/2022] Open
Abstract
Major parts of the endoplasmic reticulum (ER) in eukaryotic cells are organized as a dynamic network of membrane tubules connected by three-way junctions. On this network, self-assembled membrane domains, called ER exit sites (ERES), provide platforms at which nascent cargo proteins are packaged into vesicular carriers for subsequent transport along the secretory pathway. Although ERES appear stationary and spatially confined on long timescales, we show here via single-particle tracking that they exhibit a microtubule-dependent and heterogeneous anomalous diffusion behavior on short and intermediate timescales. By quantifying key parameters of their random walk, we show that the subdiffusive motion of ERES is distinct from that of ER junctions, i.e., ERES are not tied to junctions but rather are mobile on ER tubules. We complement and corroborate our experimental findings with model simulations that also indicate that ERES are not actively moved by microtubules. Altogether, our study shows that ERES perform a random walk on the shivering ER backbone, indirectly powered by microtubular activity. Similar phenomena can be expected for other domains on subcellular structures, setting a caveat for the interpretation of domain-tracking data.
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Affiliation(s)
- Lorenz Stadler
- Experimental Physics I, University of Bayreuth, Bayreuth, Germany
| | | | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, Bayreuth, Germany.
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19
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Shibata H. Adaptor functions of the Ca 2+-binding protein ALG-2 in protein transport from the endoplasmic reticulum. Biosci Biotechnol Biochem 2018; 83:20-32. [PMID: 30259798 DOI: 10.1080/09168451.2018.1525274] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Apoptosis-linked gene 2 (ALG-2) is a Ca2+-binding protein with five repetitive EF-hand motifs, named penta-EF-hand (PEF) domain. It interacts with various target proteins and functions as a Ca2+-dependent adaptor in diverse cellular activities. In the cytoplasm, ALG-2 is predominantly localized to a specialized region of the endoplasmic reticulum (ER), called the ER exit site (ERES), through its interaction with Sec31A. Sec31A is an outer coat protein of coat protein complex II (COPII) and is recruited from the cytosol to the ERES to form COPII-coated transport vesicles. I will overview current knowledge of the physiological significance of ALG-2 in regulating ERES localization of Sec31A and the following adaptor functions of ALG-2, including bridging Sec31A and annexin A11 to stabilize Sec31A at the ERES, polymerizing the Trk-fused gene (TFG) product, and linking MAPK1-interacting and spindle stabilizing (MISS)-like (MISSL) and microtubule-associated protein 1B (MAP1B) to promote anterograde transport from the ER.
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Affiliation(s)
- Hideki Shibata
- a Department of Applied Biosciences, Graduate School of Bioagricultural Sciences , Nagoya University , Chikusa-ku , Nagoya , Japan
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20
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Shaheen A. Effect of the unfolded protein response on ER protein export: a potential new mechanism to relieve ER stress. Cell Stress Chaperones 2018; 23:797-806. [PMID: 29730847 PMCID: PMC6111102 DOI: 10.1007/s12192-018-0905-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 04/22/2018] [Accepted: 04/24/2018] [Indexed: 02/04/2023] Open
Abstract
The unfolded protein response (UPR) is an adaptive cellular response that aims to relieve endoplasmic reticulum (ER) stress via several mechanisms, including inhibition of protein synthesis and enhancement of protein folding and degradation. There is a controversy over the effect of the UPR on ER protein export. While some investigators suggested that ER export is inhibited during ER stress, others suggested the opposite. In this article, their conflicting studies are analyzed and compared in attempt to solve this controversy. The UPR appears indeed to enhance ER export, possibly via multiple mechanisms. However, another factor, which is the integrity of the folding machinery/environment inside ER, determines whether ER export will appear increased or decreased during experimentation. Also, different methods of stress induction appear to have different effects on ER export. Thus, improvement of ER export may represent a new mechanism by which the UPR alleviates ER stress. This may help researchers to understand how the UPR works inside cells and how to manipulate it to alter cell fate during stress, either to promote cell survival or death. This may open up new approaches for the treatment of ER stress-related diseases.
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Affiliation(s)
- Alaa Shaheen
- Kafr El-Sharakwa Medical Center, Aga, Dakahlia, Egypt.
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21
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Aridor M. COPII gets in shape: Lessons derived from morphological aspects of early secretion. Traffic 2018; 19:823-839. [DOI: 10.1111/tra.12603] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/26/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Meir Aridor
- Department of Cell Biology; University of Pittsburgh School of Medicine; Pittsburgh Pennsylvania
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22
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Hanna MG, Peotter JL, Frankel EB, Audhya A. Membrane Transport at an Organelle Interface in the Early Secretory Pathway: Take Your Coat Off and Stay a While: Evolution of the metazoan early secretory pathway. Bioessays 2018; 40:e1800004. [PMID: 29741780 PMCID: PMC6166410 DOI: 10.1002/bies.201800004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 04/09/2018] [Indexed: 01/25/2023]
Abstract
Most metazoan organisms have evolved a mildly acidified and calcium diminished sorting hub in the early secretory pathway commonly referred to as the Endoplasmic Reticulum-Golgi intermediate compartment (ERGIC). These membranous vesicular-tubular clusters are found tightly juxtaposed to ER subdomains that are competent for the production of COPII-coated transport carriers. In contrast to many unicellular systems, metazoan COPII carriers largely transit just a few hundred nanometers to the ERGIC, prior to COPI-dependent transport on to the cis-Golgi. The mechanisms underlying formation and maintenance of ERGIC membranes are poorly defined. However, recent evidence suggests an important role for Trk-fused gene (TFG) in regulating the integrity of the ER/ERGIC interface. Moreover, in the absence of cytoskeletal elements to scaffold tracks on which COPII carriers might move, TFG appears to promote anterograde cargo transport by locally tethering COPII carriers adjacent to ERGIC membranes. This action, regulated in part by the intrinsically disordered domain of TFG, provides sufficient time for COPII coat disassembly prior to heterotypic membrane fusion and cargo delivery to the ERGIC.
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Affiliation(s)
- Michael G. Hanna
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health 440 Henry Mall, Madison, WI 53706, USA,
| | - Jennifer L. Peotter
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health 440 Henry Mall, Madison, WI 53706, USA,
| | - E. B. Frankel
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health 440 Henry Mall, Madison, WI 53706, USA,
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health 440 Henry Mall, Madison, WI 53706, USA,
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23
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Vagne Q, Sens P. Stochastic Model of Vesicular Sorting in Cellular Organelles. PHYSICAL REVIEW LETTERS 2018; 120:058102. [PMID: 29481197 DOI: 10.1103/physrevlett.120.058102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Indexed: 06/08/2023]
Abstract
The proper sorting of membrane components by regulated exchange between cellular organelles is crucial to intracellular organization. This process relies on the budding and fusion of transport vesicles, and should be strongly influenced by stochastic fluctuations, considering the relatively small size of many organelles. We identify the perfect sorting of two membrane components initially mixed in a single compartment as a first passage process, and we show that the mean sorting time exhibits two distinct regimes as a function of the ratio of vesicle fusion to budding rates. Low ratio values lead to fast sorting but result in a broad size distribution of sorted compartments dominated by small entities. High ratio values result in two well-defined sorted compartments but sorting is exponentially slow. Our results suggest an optimal balance between vesicle budding and fusion for the rapid and efficient sorting of membrane components and highlight the importance of stochastic effects for the steady-state organization of intracellular compartments.
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Affiliation(s)
- Quentin Vagne
- Institut Curie, PSL Research University, CNRS, UMR 168, 26 rue d'Ulm, F-75005 Paris, France
| | - Pierre Sens
- Institut Curie, PSL Research University, CNRS, UMR 168, 26 rue d'Ulm, F-75005 Paris, France
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24
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Sun J, Yu S, Zhang X, Capac C, Aligbe O, Daudelin T, Bonder EM, Gao N. A Wntless-SEC12 complex on the ER membrane regulates early Wnt secretory vesicle assembly and mature ligand export. J Cell Sci 2017; 130:2159-2171. [PMID: 28515233 DOI: 10.1242/jcs.200634] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 05/11/2017] [Indexed: 01/02/2023] Open
Abstract
Wntless (Wls) transports Wnt molecules for secretion; however, the cellular mechanism underlying the initial assembly of Wnt secretory vesicles is still not fully defined. Here, we performed proteomic and mutagenic analyses of mammalian Wls, and report a mechanism for formation of early Wnt secretory vesicles on ER membrane. Wls forms a complex with SEC12 (also known as PREB), an ER membrane-localized guanine nucleotide-exchange factor (GEF) activator of the SAR1 (the SAR1A isoform) small GTPase. Compared to palmitoylation-deficient Wnt molecules, binding of mature Wnt to Wls increases Wls-SEC12 interaction and promotes association of Wls with SAR1, the key activator of the COPII machinery. Incorporation of Wls into this exporting ER compartment is affected by Wnt ligand binding and SEC12 binding to Wls, as well as the structural integrity and, potentially, the folding of the cytosolic tail of Wls. In contrast, Wls-SEC12 binding is stable, with the interacting interface biochemically mapped to cytosolic segments of individual proteins. Mutant Wls that fails to communicate with the COPII machinery cannot effectively support Wnt secretion. These data suggest that formation of early Wnt secretory vesicles is carefully regulated to ensure proper export of functional ligands.
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Affiliation(s)
- Jiaxin Sun
- Department of Biological Sciences, Rutgers University, Newark, NJ, USA
| | - Shiyan Yu
- Department of Biological Sciences, Rutgers University, Newark, NJ, USA
| | - Xiao Zhang
- Department of Biological Sciences, Rutgers University, Newark, NJ, USA
| | - Catherine Capac
- Department of Biological Sciences, Rutgers University, Newark, NJ, USA
| | | | - Timothy Daudelin
- Department of Biological Sciences, Rutgers University, Newark, NJ, USA
| | - Edward M Bonder
- Department of Biological Sciences, Rutgers University, Newark, NJ, USA
| | - Nan Gao
- Department of Biological Sciences, Rutgers University, Newark, NJ, USA .,Rutgers Cancer Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
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25
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Amodio G, Margarucci L, Moltedo O, Casapullo A, Remondelli P. Identification of Cysteine Ubiquitylation Sites on the Sec23A Protein of the COPII Complex Required for Vesicle Formation from the ER. Open Biochem J 2017; 11:36-46. [PMID: 28553408 PMCID: PMC5427705 DOI: 10.2174/1874091x01711010036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 02/09/2017] [Accepted: 03/17/2017] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND COPII is a multiprotein complex that surrounds carrier vesicles budding from the Endoplasmic Reticulum and allows the recruitment of secretory proteins. The Sec23a protein plays a crucial role in the regulation of the dynamics of COPII formation ensuring the proper function of the secretory pathway. OBJECTIVE Since few evidences suggest that ubiquitylation could have a role in the COPII regulation, the present study was aimed to establish whether the Sec23a component of the vesicular envelope COPII could be ubiquitylated. METHOD Sec23a ubiquitylation was revealed by co-immunoprecipitation experiments. Recombinant Sec23a was gel-purified and analyzed by mass spectrometry subjected to trypsin proteolysis. Signature peptides were identified by the presence of Gly-Gly remnants from the C-terminus of the ubiquitin attached to the amino acid residues of the substrate. Recombinant Sec23a proteins bearing mutations in the ubiquitylation sites were used to evaluate the effect of ubiquitylation in the formation of COPII. RESULTS We identified two cysteine ubiquitylation sites showed at position 432 and 449 of the Sec23a protein sequence. Interestingly, we revealed that the amino acid residues of Sec23a joined to ubiquitin were cysteine instead of the conventional lysine residues. This unconventional ubiquitylation consists of the addition of one single ubiquitin moiety that is not required for Sec23a degradation. Immunofluorescence results showed that Sec23a ubiquitylation might influence COPII formation by modulating Sec23a interaction with the ER membrane. Presumably, this regulation could occur throughout continual ubiquitylation/de-ubiquityliation cycles. CONCLUSION Our results suggest a novel regulatory mechanism for the Sec23a function that could be crucial in several pathophysiological events known to alter COPII recycling.
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Affiliation(s)
- Giuseppina Amodio
- Dipartimento di Medicina, Chirurgia e Odontoiatria "Scuola Medica Salernitana", Università degli Studi di Salerno, 84084 Baronissi-Salerno, Italy
| | - Luigi Margarucci
- Dipartimento di Farmacia, Università degli Studi di Salerno, 84034 Fisciano-Salerno, Italy
| | - Ornella Moltedo
- Dipartimento di Farmacia, Università degli Studi di Salerno, 84034 Fisciano-Salerno, Italy
| | - Agostino Casapullo
- Dipartimento di Farmacia, Università degli Studi di Salerno, 84034 Fisciano-Salerno, Italy
| | - Paolo Remondelli
- Dipartimento di Medicina, Chirurgia e Odontoiatria "Scuola Medica Salernitana", Università degli Studi di Salerno, 84084 Baronissi-Salerno, Italy
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26
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Abstract
Protein secretion mediated by the secretory transport pathway is an important cellular process in eukaryotic cells. In the conventional secretory transport pathway, newly synthesized proteins pass through several endomembrane compartments en route to their specific destinations. Transport of secretory proteins between different compartments is shuttled by small, membrane-enclosed vesicles. To ensure the fidelity of transport, eukaryotic cells employ elaborate molecular machineries to accurately sort newly synthesized proteins into specific transport vesicles and precisely deliver these transport vesicles to distinct acceptor compartments. In this review, we summarize the molecular machineries that regulate each step of vesicular transport in the secretory transport pathway in yeast and animal cells.
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Affiliation(s)
- Yusong Guo
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
| | - Feng Yang
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xiao Tang
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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27
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Abstract
Transport of newly synthesized proteins from the endoplasmic reticulum (ER) to the Golgi complex is highly selective. As a general rule, such transport is limited to soluble and membrane-associated secretory proteins that have reached properly folded and assembled conformations. To secure the efficiency, fidelity, and control of this crucial transport step, cells use a combination of mechanisms. The mechanisms are based on selective retention of proteins in the ER to prevent uptake into transport vesicles, on selective capture of proteins in COPII carrier vesicles, on inclusion of proteins in these vesicles by default as part of fluid and membrane bulk flow, and on selective retrieval of proteins from post-ER compartments by retrograde vesicle transport.
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Affiliation(s)
- Charles Barlowe
- Biochemistry Department, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755;
| | - Ari Helenius
- Institute of Biochemistry, ETH Zurich, Zurich CH-8093, Switzerland
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28
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McCaughey J, Miller VJ, Stevenson NL, Brown AK, Budnik A, Heesom KJ, Alibhai D, Stephens DJ. TFG Promotes Organization of Transitional ER and Efficient Collagen Secretion. Cell Rep 2016; 15:1648-59. [PMID: 27184855 PMCID: PMC4885023 DOI: 10.1016/j.celrep.2016.04.062] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/16/2016] [Accepted: 04/15/2016] [Indexed: 12/30/2022] Open
Abstract
Collagen is the most abundant protein in the animal kingdom. It is of fundamental importance during development for cell differentiation and tissue morphogenesis as well as in pathological processes such as fibrosis and cancer cell migration. However, our understanding of the mechanisms of procollagen secretion remains limited. Here, we show that TFG organizes transitional ER (tER) and ER exit sites (ERESs) into larger structures. Depletion of TFG results in dispersion of tER elements that remain associated with individual ER-Golgi intermediate compartments (ERGICs) as largely functional ERESs. We show that TFG is not required for the transport and packaging of small soluble cargoes but is necessary for the export of procollagen from the ER. Our work therefore suggests a key relationship between the structure and function of ERESs and a central role for TFG in optimizing COPII assembly for procollagen export.
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Affiliation(s)
- Janine McCaughey
- Cell Biology Laboratories, School of Biochemistry, Faculty of Biomedical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK; Institut für Biophysik, Leibniz Universität Hannover, Herrenhäuserstraβe 2, 30419 Hannover, Germany
| | - Victoria J Miller
- Cell Biology Laboratories, School of Biochemistry, Faculty of Biomedical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Nicola L Stevenson
- Cell Biology Laboratories, School of Biochemistry, Faculty of Biomedical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Anna K Brown
- Cell Biology Laboratories, School of Biochemistry, Faculty of Biomedical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Annika Budnik
- Cell Biology Laboratories, School of Biochemistry, Faculty of Biomedical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Kate J Heesom
- Proteomics Facility, Faculty of Biomedical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Dominic Alibhai
- Wolfson Bioimaging Facility, Faculty of Biomedical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - David J Stephens
- Cell Biology Laboratories, School of Biochemistry, Faculty of Biomedical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK.
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Verissimo F, Halavatyi A, Pepperkok R, Weiss M. A microtubule-independent role of p150glued in secretory cargo concentration at endoplasmic reticulum exit sites. J Cell Sci 2015; 128:4160-70. [PMID: 26459637 DOI: 10.1242/jcs.172395] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 10/05/2015] [Indexed: 01/08/2023] Open
Abstract
Newly synthesized proteins are sorted into COPII-coated transport carriers at the endoplasmic reticulum (ER). Assembly of the COPII coat complex, which occurs at ER exit sites (ERES), is initiated by membrane association and GTP loading of SAR1, followed by the recruitment of the SEC23-SEC24 and SEC13-SEC31 subcomplexes. Both of these two subcomplexes stimulate GTP hydrolysis and coat disassembly. This inherent disassembly capacity of COPII complexes needs to be regulated to allow sufficient time for cargo sorting and transport carrier formation. By performing fluorescence recovery after photobleaching (FRAP) and mathematical modeling, we show that p150(glued) (also known as DCTN1), a component of the dynactin complex, stabilizes the COPII pre-budding complex on ER membranes in a microtubule-independent manner. Concentration of the secretory marker ts-O45-G at ERES is reduced in the presence of a C-terminal p150(glued) fragment that prevents binding of endogenous p150(glued) to SEC23. A similar cargo reduction is observed upon p150(glued) knockdown. Taken together, our data suggest that cargo concentration at ERES is regulated by p150(glued) to coordinate protein sorting and transport carrier formation with the subsequent long-range transport towards the Golgi complex along microtubules.
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Affiliation(s)
- Fatima Verissimo
- Cell Biology and Biophysics Unit, EMBL, Meyerhofstraße 1, Heidelberg D-69117, Germany
| | - Aliaksandr Halavatyi
- Cell Biology and Biophysics Unit, EMBL, Meyerhofstraße 1, Heidelberg D-69117, Germany
| | - Rainer Pepperkok
- Cell Biology and Biophysics Unit, EMBL, Meyerhofstraße 1, Heidelberg D-69117, Germany
| | - Matthias Weiss
- Experimental Physics I, Universitaetsstr. 30, University of Bayreuth, Bayreuth D-95440, Germany
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Farhan H. Systems biology of the secretory pathway: what have we learned so far? Biol Cell 2015; 107:205-17. [PMID: 25756903 DOI: 10.1111/boc.201400065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 03/04/2015] [Indexed: 12/26/2022]
Abstract
Several RNAi screens were performed in search for regulators of the secretory pathway. These screens were performed in different organisms and cell lines and relied on different readouts. Therefore, they have only little overlap among their hits, leading to the question of what we have learned from this approach so far and how these screens contributed towards an integrative understanding of the endomembrane system. The aim of this review is to revisit these screens and discuss their strengths and weaknesses as well as potential reasons for their failure to overlap with each other. As with secretory trafficking, RNAi screens were also performed on other cellular processes such as cell migration and autophagy, both of which were shown to be intimately linked to secretion. Another aim of this review is to compare the outcome of the RNAi screens on secretion, autophagy and cell migration and ask whether the functional genomic approaches have uncovered potential mechanistic insights into the links between these processes.
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Affiliation(s)
- Hesso Farhan
- Department of Biology, University of Konstanz, Konstanz, Germany.,Biotechnology Institute Thurgau, Kreuzlingen, Switzerland
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31
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Hoffmann J, Fickentscher R, Weiss M. Influence of organelle geometry on the apparent binding kinetics of peripheral membrane proteins. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:022721. [PMID: 25768545 DOI: 10.1103/physreve.91.022721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Indexed: 06/04/2023]
Abstract
Information processing in living cells frequently involves an exchange of peripheral membrane proteins between the cytosol and organelle membranes. The typical time scale τ of these association-dissociation cycles is commonly quantified in vivo via fluorescence recovery after photobleaching (FRAP). Contrary to common assumptions, we show here that τ values determined by FRAP depend on the size and number of target structures. Hence, FRAP times alone are insufficient to draw conclusions about the proteins' binding kinetics. In contrast, extracting primary molecular association and dissociation rates from FRAP approaches provides a size-independent and therefore robust measure for the proteins' binding kinetics. We support our theoretical considerations with experiments on the small GTPase Arf-1 that transiently associates with Golgi membranes: While Arf-1 recovery times in untreated cells and in cells with disrupted microtubules are significantly different, the molecular kinetic rates are shown to be the same in both cases.
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Affiliation(s)
- Julia Hoffmann
- Experimental Physics I, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Rolf Fickentscher
- Experimental Physics I, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
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Tillmann KD, Reiterer V, Baschieri F, Hoffmann J, Millarte V, Hauser MA, Mazza A, Atias N, Legler DF, Sharan R, Weiss M, Farhan H. Regulation of Sec16 levels and dynamics links proliferation and secretion. J Cell Sci 2014; 128:670-82. [PMID: 25526736 DOI: 10.1242/jcs.157115] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We currently lack a broader mechanistic understanding of the integration of the early secretory pathway with other homeostatic processes such as cell growth. Here, we explore the possibility that Sec16A, a major constituent of endoplasmic reticulum exit sites (ERES), acts as an integrator of growth factor signaling. Surprisingly, we find that Sec16A is a short-lived protein that is regulated by growth factors in a manner dependent on Egr family transcription factors. We hypothesize that Sec16A acts as a central node in a coherent feed-forward loop that detects persistent growth factor stimuli to increase ERES number. Consistent with this notion, Sec16A is also regulated by short-term growth factor treatment that leads to increased turnover of Sec16A at ERES. Finally, we demonstrate that Sec16A depletion reduces proliferation, whereas its overexpression increases proliferation. Together with our finding that growth factors regulate Sec16A levels and its dynamics on ERES, we propose that this protein acts as an integrator linking growth factor signaling and secretion. This provides a mechanistic basis for the previously proposed link between secretion and proliferation.
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Affiliation(s)
- Kerstin D Tillmann
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Unterseestrasse 47, CH-8280 Kreuzlingen, Switzerland University of Konstanz, Universitätsstrasse 10, Konstanz 78464, Germany
| | - Veronika Reiterer
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Unterseestrasse 47, CH-8280 Kreuzlingen, Switzerland
| | - Francesco Baschieri
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Unterseestrasse 47, CH-8280 Kreuzlingen, Switzerland University of Konstanz, Universitätsstrasse 10, Konstanz 78464, Germany
| | - Julia Hoffmann
- Experimental Physics I, University of Bayreuth, Bayreuth 95440, Germany
| | - Valentina Millarte
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Unterseestrasse 47, CH-8280 Kreuzlingen, Switzerland University of Konstanz, Universitätsstrasse 10, Konstanz 78464, Germany
| | - Mark A Hauser
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Unterseestrasse 47, CH-8280 Kreuzlingen, Switzerland
| | - Arnon Mazza
- Blavatnik School of Computer Science, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Nir Atias
- Blavatnik School of Computer Science, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Daniel F Legler
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Unterseestrasse 47, CH-8280 Kreuzlingen, Switzerland
| | - Roded Sharan
- Blavatnik School of Computer Science, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, Bayreuth 95440, Germany
| | - Hesso Farhan
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Unterseestrasse 47, CH-8280 Kreuzlingen, Switzerland University of Konstanz, Universitätsstrasse 10, Konstanz 78464, Germany
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Vesicles bearing Toxoplasma apicoplast membrane proteins persist following loss of the relict plastid or Golgi body disruption. PLoS One 2014; 9:e112096. [PMID: 25369183 PMCID: PMC4219833 DOI: 10.1371/journal.pone.0112096] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 10/13/2014] [Indexed: 12/16/2022] Open
Abstract
Toxoplasma gondii and malaria parasites contain a unique and essential relict plastid called the apicoplast. Most apicoplast proteins are encoded in the nucleus and are transported to the organelle via the endoplasmic reticulum (ER). Three trafficking routes have been proposed for apicoplast membrane proteins: (i) vesicular trafficking from the ER to the Golgi and then to the apicoplast, (ii) contiguity between the ER membrane and the apicoplast allowing direct flow of proteins, and (iii) vesicular transport directly from the ER to the apicoplast. Previously, we identified a set of membrane proteins of the T. gondii apicoplast which were also detected in large vesicles near the organelle. Data presented here show that the large vesicles bearing apicoplast membrane proteins are not the major carriers of luminal proteins. The vesicles continue to appear in parasites which have lost their plastid due to mis-segregation, indicating that the vesicles are not derived from the apicoplast. To test for a role of the Golgi body in vesicle formation, parasites were treated with brefeldin A or transiently transfected with a dominant-negative mutant of Sar1, a GTPase required for ER to Golgi trafficking. The immunofluorescence patterns showed little change. These findings were confirmed using stable transfectants, which expressed the toxic dominant-negative sar1 following Cre-loxP mediated promoter juxtaposition. Our data support the hypothesis that the large vesicles do not mediate the trafficking of luminal proteins to the apicoplast. The results further show that the large vesicles bearing apicoplast membrane proteins continue to be observed in the absence of Golgi and plastid function. These data raise the possibility that the apicoplast proteome is generated by two novel ER to plastid trafficking pathways, plus the small set of proteins encoded by the apicoplast genome.
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Ronchi P, Tischer C, Acehan D, Pepperkok R. Positive feedback between Golgi membranes, microtubules and ER exit sites directs de novo biogenesis of the Golgi. J Cell Sci 2014; 127:4620-33. [PMID: 25189616 DOI: 10.1242/jcs.150474] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Golgi complex is the central organelle of the secretory pathway. It undergoes dynamic changes during the cell cycle, but how it acquires and maintains its complex structure is unclear. To address this question, we have used laser nanosurgery to deplete BSC1 cells of the Golgi complex and have monitored its biogenesis by quantitative time-lapse microscopy and correlative electron microscopy. After Golgi depletion, endoplasmic reticulum (ER) export is inhibited and the number of ER exit sites (ERES) is reduced and does not increase for several hours. Occasional fusion of small post-ER carriers to form the first larger structures triggers a rapid and drastic growth of Golgi precursors, due to the capacity of these structures to attract more carriers by microtubule nucleation and to stimulate ERES biogenesis. Increasing the chances of post-ER carrier fusion close to ERES by depolymerizing microtubules results in the acceleration of Golgi and ERES biogenesis. Taken together, on the basis of our results, we propose a self-organizing principle of the early secretory pathway that integrates Golgi biogenesis, ERES biogenesis and the organization of the microtubule network by positive-feedback loops.
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Affiliation(s)
- Paolo Ronchi
- European Molecular Biology Laboratory (EMBL), Cell biology and biophysics unit
| | - Christian Tischer
- European Molecular Biology Laboratory (EMBL), Advanced Light Microscopy
| | - Devrim Acehan
- European Molecular Biology Laboratory (EMBL), Electron Microscopy Core Facilities, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Rainer Pepperkok
- European Molecular Biology Laboratory (EMBL), Cell biology and biophysics unit European Molecular Biology Laboratory (EMBL), Advanced Light Microscopy
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Abstract
Proteins synthesised at the endoplasmic reticulum (ER) have to undergo a number of consecutive and coordinated steps to reach the Golgi complex. To understand the dynamic complexity of ER-to-Golgi transport at the structural and molecular level, light microscopy approaches are fundamental tools that allow in vivo observations of protein dynamics and interactions of fluorescent proteins in living cells. Imaging protein and organelle dynamics close to the ultra-structural level became possible by combining light microscopy with electron microscopy analyses or super-resolution light microscopy methods. Besides, increasing evidence suggests that the early secretory pathway is tightly connected to other cellular processes, such as signal transduction, and quantitative information at the systems level is fundamental to achieve a comprehensive molecular understanding of these connections. High-throughput microscopy in fixed and living cells in combination with systematic perturbation of gene expression by, e.g. RNA interference, will open new avenues to gain such an understanding of the early secretory pathway at the systems level. In this Commentary, we first outline examples that revealed the dynamic organisation of ER-to-Golgi transport in living cells. Next, we discuss the use of advanced imaging methods in studying ER-to-Golgi transport and, finally, delineate the efforts in understanding ER-to-Golgi transport at the systems level.
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Affiliation(s)
- Fatima Verissimo
- European Molecular Biology Laboratory, Cell Biology and Cell Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
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36
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Klinkenberg D, Long KR, Shome K, Watkins SC, Aridor M. A cascade of ER exit site assembly that is regulated by p125A and lipid signals. J Cell Sci 2014; 127:1765-78. [PMID: 24522181 DOI: 10.1242/jcs.138784] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The inner and outer layers of COPII mediate cargo sorting and vesicle biogenesis. Sec16A and p125A (officially known as SEC23IP) proteins interact with both layers to control coat activity, yet the steps directing functional assembly at ER exit sites (ERES) remain undefined. By using temperature blocks, we find that Sec16A is spatially segregated from p125A-COPII-coated ERES prior to ER exit at a step that required p125A. p125A used lipid signals to control ERES assembly. Within p125A, we defined a C-terminal DDHD domain found in phospholipases and PI transfer proteins that recognized PA and phosphatidylinositol phosphates in vitro and was targeted to PI4P-rich membranes in cells. A conserved central SAM domain promoted self-assembly and selective lipid recognition by the DDHD domain. A basic cluster and a hydrophobic interface in the DDHD and SAM domains, respectively, were required for p125A-mediated functional ERES assembly. Lipid recognition by the SAM-DDHD module was used to stabilize membrane association and regulate the spatial segregation of COPII from Sec16A, nucleating the coat at ERES for ER exit.
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Affiliation(s)
- David Klinkenberg
- Department of Cell Biology, University of Pittsburgh School of Medicine, 3500 Terrace Street, Pittsburgh, PA 15261, USA
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37
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Tischer C, Hilsenstein V, Hanson K, Pepperkok R. Adaptive fluorescence microscopy by online feedback image analysis. Methods Cell Biol 2014; 123:489-503. [PMID: 24974044 DOI: 10.1016/b978-0-12-420138-5.00026-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Obtaining sufficient statistics in quantitative fluorescence microscopy is often hampered by the tedious and time-consuming task of manually locating comparable specimen and repeatedly launching the same acquisition protocol. Recent advances in combining fluorescence microscopy with online image analysis tackle this problem by fully integrating the task of identifying and locating the specimen of interest in an automated acquisition workflow. Here, we describe the general requirements and specific microscope control and image analysis software solutions for implementing such automated online feedback microscopy. We demonstrate the power of the method by two selected applications addressing high-throughput 3D imaging of sparsely parasite-infected tissue culture cells and automated fluorescence recovery after photobleaching experiments to quantify the turnover of vesicular coat proteins at ER exit sites.
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38
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Takagi J, Renna L, Takahashi H, Koumoto Y, Tamura K, Stefano G, Fukao Y, Kondo M, Nishimura M, Shimada T, Brandizzi F, Hara-Nishimura I. MAIGO5 functions in protein export from Golgi-associated endoplasmic reticulum exit sites in Arabidopsis. THE PLANT CELL 2013; 25:4658-75. [PMID: 24280388 PMCID: PMC3875742 DOI: 10.1105/tpc.113.118158] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 10/08/2013] [Accepted: 10/22/2013] [Indexed: 05/19/2023]
Abstract
Plant cells face unique challenges to efficiently export cargo from the endoplasmic reticulum (ER) to mobile Golgi stacks. Coat protein complex II (COPII) components, which include two heterodimers of Secretory23/24 (Sec23/24) and Sec13/31, facilitate selective cargo export from the ER; however, little is known about the mechanisms that regulate their recruitment to the ER membrane, especially in plants. Here, we report a protein transport mutant of Arabidopsis thaliana, named maigo5 (mag5), which abnormally accumulates precursor forms of storage proteins in seeds. mag5-1 has a deletion in the putative ortholog of the Saccharomyces cerevisiae and Homo sapiens Sec16, which encodes a critical component of ER exit sites (ERESs). mag mutants developed abnormal structures (MAG bodies) within the ER and exhibited compromised ER export. A functional MAG5/SEC16A-green fluorescent protein fusion localized at Golgi-associated cup-shaped ERESs and cycled on and off these sites at a slower rate than the COPII coat. MAG5/SEC16A interacted with SEC13 and SEC31; however, in the absence of MAG5/SEC16A, recruitment of the COPII coat to ERESs was accelerated. Our results identify a key component of ER export in plants by demonstrating that MAG5/SEC16A is required for protein export at ERESs that are associated with mobile Golgi stacks, where it regulates COPII coat turnover.
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Affiliation(s)
- Junpei Takagi
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Luciana Renna
- Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Hideyuki Takahashi
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yasuko Koumoto
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kentaro Tamura
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Giovanni Stefano
- Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Yoichiro Fukao
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Maki Kondo
- Department of Cell Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Mikio Nishimura
- Department of Cell Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Tomoo Shimada
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Federica Brandizzi
- Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Ikuko Hara-Nishimura
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
- Address correspondence to
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Evensen NA, Kuscu C, Nguyen HL, Zarrabi K, Dufour A, Kadam P, Hu YJ, Pulkoski-Gross A, Bahou WF, Zucker S, Cao J. Unraveling the role of KIAA1199, a novel endoplasmic reticulum protein, in cancer cell migration. J Natl Cancer Inst 2013; 105:1402-16. [PMID: 23990668 DOI: 10.1093/jnci/djt224] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Cell migration is a critical determinant of cancer metastasis, and a better understanding of the genes involved will lead to the identification of novel targets aimed at preventing cancer dissemination. KIAA1199 has been shown to be upregulated in human cancers, yet its role in cancer progression was hitherto unknown. METHODS Clinical relevance was assessed by examining KIAA1199 expression in human cancer specimens. In vitro and in vivo studies were employed to determine the function of KIAA1199 in cancer progression. Cellular localization of KIAA1199 was microscopically determined. SNAP-tag pull-down assays were used to identify binding partner(s) of KIAA1199. Calcium levels were evaluated using spectrofluorometric and fluorescence resonance energy transfer analyses. Signaling pathways were dissected by Western blotting. Student t test was used to assess differences. All statistical tests were two-sided. RESULTS KIAA1199 was upregulated in invasive breast cancer specimens and inversely associated with patient survival rate. Silencing of KIAA1199 in MDA-MB-435 cancer cells resulted in a mesenchymal-to-epithelial transition that reduced cell migratory ability in vitro (75% reduction; P < .001) and decreased metastasis in vivo (80% reduction; P < .001). Gain-of-function assays further demonstrated the role of KIAA1199 in cell migration. KIAA1199-enhanced cell migration required endoplasmic reticulum (ER) localization, where it forms a stable complex with the chaperone binding immunoglobulin protein (BiP). A novel ER-retention motif within KIAA1199 that is required for its ER localization, BiP interaction, and enhanced cell migration was identified. Mechanistically, KIAA1199 was found to mediate ER calcium leakage, and the resultant increase in cytosolic calcium ultimately led to protein kinase C alpha activation and cell migration. CONCLUSIONS KIAA1199 serves as a novel cell migration-promoting gene and plays a critical role in maintaining cancer mesenchymal status.
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Affiliation(s)
- Nikki A Evensen
- Affiliations of authors: Department of Medicine/Cancer Prevention (NAE, CK, H-LN, KZ, AD, AP-G, JC), Department of Pathology (YH, JC), Department of Medicine/Hematology & Oncology (WFB, SZ), Stony Brook University, Stony Brook, NY; Department of Research, Veterans Affair Medical Center, Northport, NY (H-LN, PK, SZ); Centre for Blood Research and Departments of Biochemistry and Molecular Biology and Oral Biological and Medical Sciences, University of British Columbia, Vancouver, BC, Canada (AD)
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Amodio G, Venditti R, De Matteis MA, Moltedo O, Pignataro P, Remondelli P. Endoplasmic reticulum stress reduces COPII vesicle formation and modifies Sec23a cycling at ERESs. FEBS Lett 2013; 587:3261-6. [PMID: 23994533 DOI: 10.1016/j.febslet.2013.08.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 08/08/2013] [Indexed: 01/03/2023]
Abstract
Exit from the Endoplasmic Reticulum (ER) of newly synthesized proteins is mediated by COPII vesicles that bud from the ER at the ER Exit Sites (ERESs). Disruption of ER homeostasis causes accumulation of unfolded and misfolded proteins in the ER. This condition is referred to as ER stress. Previously, we demonstrated that ER stress rapidly impairs the formation of COPII vesicles. Here, we show that membrane association of COPII components, and in particular of Sec23a, is impaired by ER stress-inducing agents suggesting the existence of a dynamic interplay between protein folding and COPII assembly at the ER.
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Affiliation(s)
- Giuseppina Amodio
- Dipartimento di Farmacia, Università degli Studi di Salerno, 84084 Fisciano, Salerno, Italy
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41
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Adolf F, Herrmann A, Hellwig A, Beck R, Brügger B, Wieland FT. Scission of COPI and COPII vesicles is independent of GTP hydrolysis. Traffic 2013; 14:922-32. [PMID: 23691917 DOI: 10.1111/tra.12084] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 05/15/2013] [Accepted: 05/20/2013] [Indexed: 12/29/2022]
Abstract
Intracellular transport and maintenance of the endomembrane system in eukaryotes depends on formation and fusion of vesicular carriers. A seeming discrepancy exists in the literature about the basic mechanism in the scission of transport vesicles that depend on GTP-binding proteins. Some reports describe that the scission of COP-coated vesicles is dependent on GTP hydrolysis, whereas others found that GTP hydrolysis is not required. In order to investigate this pivotal mechanism in vesicle formation, we analyzed formation of COPI- and COPII-coated vesicles utilizing semi-intact cells. The small GTPases Sar1 and Arf1 together with their corresponding coat proteins, the Sec23/24 and Sec13/31 complexes for COPII and coatomer for COPI vesicles were required and sufficient to drive vesicle formation. Both types of vesicles were efficiently generated when GTP hydrolysis was blocked either by utilizing the poorly hydrolyzable GTP analogs GTPγS and GMP-PNP, or with constitutively active mutants of the small GTPases. Thus, GTP hydrolysis is not required for the formation and release of COP vesicles.
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Affiliation(s)
- Frank Adolf
- Heidelberg University Biochemistry Center, University of Heidelberg, Im Neuenheimer Feld 328, D-69120, Heidelberg, Germany
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42
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Yeong FM. Multi-step down-regulation of the secretory pathway in mitosis: a fresh perspective on protein trafficking. Bioessays 2013; 35:462-71. [PMID: 23494566 PMCID: PMC3654163 DOI: 10.1002/bies.201200144] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The secretory pathway delivers proteins synthesized at the rough endoplasmic reticulum (RER) to various subcellular locations via the Golgi apparatus. Currently, efforts are focused on understanding the molecular machineries driving individual processes at the RER and Golgi that package, modify and transport proteins. However, studies are routinely performed using non-dividing cells. This obscures the critical issue of how the secretory pathway is affected by cell division. Indeed, several studies have indicated that protein trafficking is down-regulated during mitosis. Moreover, the RER and Golgi apparatus exhibit gross reorganization in mitosis. Here I provide a relatively neglected perspective of how the mitotic cyclin-dependent kinase (CDK1) could regulate various stages of the secretory pathway. I highlight several aspects of the mitotic control of protein trafficking that remain unresolved and suggest that further studies on how the mitotic CDK1 influences the secretory pathway are necessary to obtain a deeper understanding of protein transport.
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Affiliation(s)
- Foong May Yeong
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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43
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D'Arcangelo JG, Stahmer KR, Miller EA. Vesicle-mediated export from the ER: COPII coat function and regulation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2464-72. [PMID: 23419775 DOI: 10.1016/j.bbamcr.2013.02.003] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 02/04/2013] [Accepted: 02/05/2013] [Indexed: 11/26/2022]
Abstract
Vesicle trafficking from the endoplasmic reticulum (ER) is a vital cellular process in all eukaryotes responsible for moving secretory cargoes from the ER to the Golgi apparatus. To accomplish this feat, the cell employs a set of conserved cytoplasmic coat proteins - the coat protein II (COPII) complex - that recruit cargo into nascent buds and deform the ER membrane to drive vesicle formation. While our understanding of COPII coat mechanics has developed substantially since its discovery, we have only recently begun to appreciate the factors that regulate this complex and, in turn, ER-to-Golgi trafficking. Here, we describe these factors and their influences on COPII vesicle formation. Properties intrinsic to the GTP cycle of the coat, as well as coat structure, have critical implications for COPII vesicle trafficking. Extrinsic factors in the cytosol can modulate COPII activity through direct interaction with the coat or with scaffolding components, or by changing composition of the ER membrane. Further, lumenal and membrane-bound cargoes and cargo receptors can influence COPII-mediated trafficking in equally profound ways. Together, these factors work in concert to ensure proper cargo movement in this first step of the secretory pathway. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum.
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Lu L, Hannoush RN, Goess BC, Varadarajan S, Shair MD, Kirchhausen T. The small molecule dispergo tubulates the endoplasmic reticulum and inhibits export. Mol Biol Cell 2013; 24:1020-9. [PMID: 23389632 PMCID: PMC3608490 DOI: 10.1091/mbc.e12-08-0575] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A small molecule called dispergo is identified that acutely and reversibly induces ER tubulation and the ER export block that results in the gradual merge of the Golgi membrane with the ER. It is the first reported small molecule with such a phenotype and could facilitate the functional study of the ER. The mammalian endoplasmic reticulum (ER) is an organelle that maintains a complex, compartmentalized organization of interconnected cisternae and tubules while supporting a continuous flow of newly synthesized proteins and lipids to the Golgi apparatus. Using a phenotypic screen, we identify a small molecule, dispergo, that induces reversible loss of the ER cisternae and extensive ER tubulation, including formation of ER patches comprising densely packed tubules. Dispergo also prevents export from the ER to the Golgi apparatus, and this traffic block results in breakdown of the Golgi apparatus, primarily due to maintenance of the constitutive retrograde transport of its components to the ER. The effects of dispergo are reversible, since its removal allows recovery of the ER cisternae at the expense of the densely packed tubular ER patches. This recovery occurs together with reactivation of ER-to-Golgi traffic and regeneration of a functional Golgi with correct morphology. Because dispergo is the first small molecule that reversibly tubulates the ER and inhibits its export function, it will be useful in studying these complex processes.
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Affiliation(s)
- Lei Lu
- Department of Cell Biology, Harvard Medical School, MA, USA
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Lord C, Ferro-Novick S, Miller EA. The highly conserved COPII coat complex sorts cargo from the endoplasmic reticulum and targets it to the golgi. Cold Spring Harb Perspect Biol 2013; 5:5/2/a013367. [PMID: 23378591 DOI: 10.1101/cshperspect.a013367] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Protein egress from the endoplasmic reticulum (ER) is driven by a conserved cytoplasmic coat complex called the COPII coat. The COPII coat complex contains an inner shell (Sec23/Sec24) that sorts cargo into ER-derived vesicles and an outer cage (Sec13/Sec31) that leads to coat polymerization. Once released from the ER, vesicles must tether to and fuse with the target membrane to deliver their protein and lipid contents. This delivery step also depends on the COPII coat, with coat proteins binding directly to tethering and regulatory factors. Recent findings have yielded new insight into how COPII-mediated vesicle traffic is regulated. Here we discuss the molecular basis of COPII-mediated ER-Golgi traffic, focusing on the surprising complexity of how ER-derived vesicles form, package diverse cargoes, and correctly target these cargoes to their destination.
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Affiliation(s)
- Christopher Lord
- Department of Cellular and Molecular Medicine, Howard Hughes Medical Institute, University of California at San Diego, La Jolla, CA 92093, USA
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Koreishi M, Yu S, Oda M, Honjo Y, Satoh A. CK2 phosphorylates Sec31 and regulates ER-To-Golgi trafficking. PLoS One 2013; 8:e54382. [PMID: 23349870 PMCID: PMC3548793 DOI: 10.1371/journal.pone.0054382] [Citation(s) in RCA: 48] [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: 08/18/2012] [Accepted: 12/11/2012] [Indexed: 01/09/2023] Open
Abstract
Protein export from the endoplasmic reticulum (ER) is an initial and rate-limiting step of molecular trafficking and secretion. This is mediated by coat protein II (COPII)-coated vesicles, whose formation requires small GTPase Sar1 and 6 Sec proteins including Sec23 and Sec31. Sec31 is a component of the outer layer of COPII coat and has been identified as a phosphoprotein. The initiation and promotion of COPII vesicle formation is regulated by Sar1; however, the mechanism regulating the completion of COPII vesicle formation followed by vesicle release is largely unknown. Hypothesizing that the Sec31 phosphorylation may be such a mechanism, we identified phosphorylation sites in the middle linker region of Sec31. Sec31 phosphorylation appeared to decrease its association with ER membranes and Sec23. Non-phosphorylatable mutant of Sec31 stayed longer at ER exit sites and bound more strongly to Sec23. We also found that CK2 is one of the kinases responsible for Sec31 phosphorylation because CK2 knockdown decreased Sec31 phosphorylation, whereas CK2 overexpression increased Sec31 phosphorylation. Furthermore, CK2 knockdown increased affinity of Sec31 for Sec23 and inhibited ER-to-Golgi trafficking. These results suggest that Sec31 phosphorylation by CK2 controls the duration of COPII vesicle formation, which regulates ER-to-Golgi trafficking.
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Affiliation(s)
- Mayuko Koreishi
- The Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Sidney Yu
- School of Biomedical Sciences and Epithelial Cell Biology Research Center, The Chinese University of Hong Kong, Hong Kong, People’s Republic of China
| | - Mayumi Oda
- The Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Yasuko Honjo
- The Research Core for Interdisciplinary Sciences (RCIS), Okayama University, Okayama, Japan
| | - Ayano Satoh
- The Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
- * E-mail:
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Abstract
In this chapter, we summarize recent theoretical efforts to address a variety of issues in Golgi morphogenesis: de novo biogenesis of compartments with precise chemical identity, the transport of proteins through the Golgi, the maintenance of chemical identity, and the morphology of Golgi compartments, from the perspective of nonequilibrium physics.
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Affiliation(s)
- Pierre Sens
- Laboratoire Gulliver, CNRS-ESPCI, UMR 7083, 75231 Paris, France
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48
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Abstract
Steady increase in the incidence of atherosclerosis is becoming a major concern not only in the United States but also in other countries. One of the major risk factors for the development of atherosclerosis is high concentrations of plasma low-density lipoprotein, which are metabolic products of very low-density lipoprotein (VLDL). VLDLs are synthesized and secreted by the liver. In this review, we discuss various stages through which VLDL particles go from their biogenesis to secretion in the circulatory system. Once VLDLs are synthesized in the lumen of the endoplasmic reticulum, they are transported to the Golgi. The transport of nascent VLDLs from the endoplasmic reticulum to Golgi is a complex multistep process, which is mediated by a specialized transport vesicle, the VLDL transport vesicle. The VLDL transport vesicle delivers VLDLs to the cis-Golgi lumen where nascent VLDLs undergo a number of essential modifications. The mature VLDL particles are then transported to the plasma membrane and secreted in the circulatory system. Understanding of molecular mechanisms and identification of factors regulating the complex intracellular VLDL trafficking will provide insight into the pathophysiology of various metabolic disorders associated with abnormal VLDL secretion and identify potential new therapeutic targets.
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Affiliation(s)
- Samata Tiwari
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, 6900 Lake Nona Boulevard, Orlando, FL 32827, USA
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Hanulová M, Weiss M. Membrane-mediated interactions – a physico-chemical basis for protein sorting. Mol Membr Biol 2012; 29:177-85. [DOI: 10.3109/09687688.2012.667838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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50
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Hanulová M, Weiss M. Protein sorting and membrane-mediated interactions. Biophys Rev 2012; 4:117-124. [PMID: 28510092 DOI: 10.1007/s12551-012-0069-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 01/24/2012] [Indexed: 11/30/2022] Open
Abstract
Sorting of membrane proteins is of vital importance for living cells. Indeed, roughly one-third of a eukaryotic cell's proteome consists of peripheral and transmembrane proteins. These need to be properly distributed and dynamically maintained at distinct locations in the compartmentalized cell, and one may wonder how proteins determine where, when, and how to travel to reach a specific organelle. While specific binary interactions between proteins have been invoked in explaining the trafficking and sorting processes, a more active role of lipids in this context has become visible in recent years. In particular, membrane-mediated interactions have been suggested to serve as a robust physicochemical mechanism to facilitate protein sorting. Here, we will review some recent insights into these aspects.
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Affiliation(s)
- Mária Hanulová
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, D-95440, Bayreuth, Germany
| | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, D-95440, Bayreuth, Germany.
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