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Held A, Lapka J, Sargeant J, Hojanazarova J, Shaheen A, Galindo S, Madreiter-Sokolowski C, Malli R, Graier WF, Hay JC. Steady-state regulation of COPII-dependent secretory cargo sorting by inositol trisphosphate receptors, calcium, and penta EF hand proteins. J Biol Chem 2023; 299:105471. [PMID: 37979918 PMCID: PMC10750190 DOI: 10.1016/j.jbc.2023.105471] [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: 07/01/2023] [Revised: 10/30/2023] [Accepted: 11/02/2023] [Indexed: 11/20/2023] Open
Abstract
Recently, we demonstrated that agonist-stimulated Ca2+ signaling involving IP3 receptors modulates ER export rates through activation of the penta-EF Hand proteins apoptosis-linked gene-2 (ALG-2) and peflin. It is unknown, however, whether IP3Rs and penta-EF proteins regulate ER export rates at steady state. Here we tested this idea in normal rat kidney epithelial cells by manipulation of IP3R isoform expression. Under standard growth conditions, spontaneous cytosolic Ca2+ oscillations occurred simultaneously in successive groups of contiguous cells, generating intercellular Ca2+ waves that moved across the monolayer periodically. Depletion of IP3R-3, typically the least promiscuous IP3R isoform, caused increased cell participation in intercellular Ca2+ waves in unstimulated cells. The increased spontaneous signaling was sufficient to cause increased ALG-2 and COPII coat subunit Sec31A and decreased peflin localization at ER exit sites, resulting in increased ER-to-Golgi transport of the COPII client cargo VSV-G. The elevated ER-to-Golgi transport caused greater concentration of VSV-G at ER exit sites and had reciprocal effects on transport of VSV-G and a bulk-flow cargo, though both cargos equally required Sec31A. Inactivation of client cargo sorting using 4-phenylbutyrate had opposing reciprocal effects on client and bulk-flow cargo and neutralized any effect of ALG-2 activation on transport. This work extends our knowledge of ALG-2 mechanisms and indicates that in normal rat kidney cells, IP3R isoforms regulate homeostatic Ca2+ signaling that helps determine the basal secretion rate and stringency of COPII-dependent cargo sorting.
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Affiliation(s)
- Aaron Held
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Jacob Lapka
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - John Sargeant
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Jennet Hojanazarova
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Alaa Shaheen
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Samuel Galindo
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Corina Madreiter-Sokolowski
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Jesse C Hay
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA.
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2
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Abstract
Constitutive vesicle trafficking is the default pathway used by all cells for movement of intracellular cargoes between subcellular compartments and in and out of the cell. Classically, constitutive trafficking was thought to be continuous and unregulated, in contrast to regulated secretion, wherein vesicles are stored intracellularly until undergoing synchronous membrane fusion following a Ca2+ signal. However, as shown in the literature reviewed here, many continuous trafficking steps can be up- or down-regulated by Ca2+, including several steps associated with human pathologies. Notably, we describe a series of Ca2+ pumps, channels, Ca2+-binding effector proteins, and their trafficking machinery targets that together regulate the flux of cargo in response to genetic alterations as well as baseline and agonist-dependent Ca2+ signals. Here, we review the most recent advances, organized by organellar location, that establish the importance of these components in trafficking steps. Ultimately, we conclude that Ca2+ regulates an expanding series of distinct mechanistic steps. Furthermore, the involvement of Ca2+ in trafficking is complex. For example, in some cases, the same Ca2+ effectors regulate surprisingly distinct trafficking steps, or even the same trafficking step with opposing influences, through binding to different target proteins.
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Affiliation(s)
- John Sargeant
- Division of Biological Sciences & Center for Structural & Functional Neuroscience, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
| | - Jesse C Hay
- Division of Biological Sciences & Center for Structural & Functional Neuroscience, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
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3
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Sargeant J, Seiler DK, Costain T, Madreiter-Sokolowski CT, Gordon DE, Peden AA, Malli R, Graier WF, Hay JC. ALG-2 and peflin regulate COPII targeting and secretion in response to calcium signaling. J Biol Chem 2021; 297:101393. [PMID: 34762908 PMCID: PMC8671942 DOI: 10.1016/j.jbc.2021.101393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 11/01/2021] [Accepted: 11/05/2021] [Indexed: 02/05/2023] Open
Abstract
ER-to-Golgi transport is the first step in the constitutive secretory pathway, which, unlike regulated secretion, is believed to proceed nonstop independent of Ca2+ flux. However, here we demonstrate that penta-EF hand (PEF) proteins ALG-2 and peflin constitute a hetero-bifunctional COPII regulator that responds to Ca2+ signaling by adopting one of several distinct activity states. Functionally, these states can adjust the rate of ER export of COPII-sorted cargos up or down by ∼50%. We found that at steady-state Ca2+, ALG-2/peflin hetero-complexes bind to ER exit sites (ERES) through the ALG-2 subunit to confer a low, buffered secretion rate, while peflin-lacking ALG-2 complexes markedly stimulate secretion. Upon Ca2+ signaling, ALG-2 complexes lacking peflin can either increase or decrease the secretion rate depending on signaling intensity and duration-phenomena that could contribute to cellular growth and intercellular communication following secretory increases or protection from excitotoxicity and infection following decreases. In epithelial normal rat kidney (NRK) cells, the Ca2+-mobilizing agonist ATP causes ALG-2 to depress ER export, while in neuroendocrine PC12 cells, Ca2+ mobilization by ATP results in ALG-2-dependent enhancement of secretion. Furthermore, distinct Ca2+ signaling patterns in NRK cells produce opposing ALG-2-dependent effects on secretion. Mechanistically, ALG-2-dependent depression of secretion involves decreased levels of the COPII outer shell and increased peflin targeting to ERES, while ALG-2-dependent enhancement of secretion involves increased COPII outer shell and decreased peflin at ERES. These data provide insights into how PEF protein dynamics affect secretion of important physiological cargoes such as collagen I and significantly impact ER stress.
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Affiliation(s)
- John Sargeant
- Division of Biological Sciences, Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Danette Kowal Seiler
- Division of Biological Sciences, Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Tucker Costain
- Division of Biological Sciences, Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | | | - David E Gordon
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California, USA
| | - Andrew A Peden
- Department of Biomedical Science and Centre for Membrane Interactions and Dynamics, The University of Sheffield, Sheffield, United Kingdom
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Jesse C Hay
- Division of Biological Sciences, Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana, USA.
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4
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Ylä-Anttila P, Gupta S, Masucci MG. The Epstein-Barr virus deubiquitinase BPLF1 targets SQSTM1/p62 to inhibit selective autophagy. Autophagy 2021; 17:3461-3474. [PMID: 33509017 PMCID: PMC8632276 DOI: 10.1080/15548627.2021.1874660] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Macroautophagy/autophagy plays an important role in the control of viral infections and viruses have evolved multiple strategies to interfere with autophagy to avoid destruction and promote their own replication and spread. Here we report that the deubiquitinase encoded in the N-terminal domain of the Epstein-Barr virus (EBV) large tegument protein, BPLF1, regulates selective autophagy. Mass spectrometry analysis identified several vesicular traffic and autophagy related proteins as BPLF1 interactors and potential substrates, suggesting that the viral protein targets this cellular defense during productive infection. Direct binding of BPLF1 to the autophagy receptor SQSTM1/p62 (sequestosome 1) was confirmed by co-immunoprecipitation of transfected BPLF1 and by in vitro affinity isolation of bacterially expressed proteins. Expression of the catalytically active BPLF1 was associated with decreased SQSTM1/p62 ubiquitination and failure to recruit LC3 to SQSTM1/p62-positive aggregates. Selective autophagy was inhibited as illustrated by the accumulation of large protein aggregates in BPLF1-positive cells co-transfected with an aggregate-prone HTT (huntingtin)-Q109 construct, and by a slower autophagy-dependent clearance of protein aggregates upon transfection of BPLF1 in cells expressing a tetracycline-regulated HTT-Q103. The inhibition of aggregate clearance was restored by overexpression of a SQSTM1/p62[E409A,K420R] mutant that does not require ubiquitination of Lys420 for cargo loading. These findings highlight a previously unrecognized role of the viral deubiquitinase in the regulation of selective autophagy, which may promote infection and the production of infectious virus.Abbreviations: BPLF1, BamH1 fragment left open reading frame-1; EBV, Epstein-Barr virus; GFP, green fluorescent protein; HTT, huntingtin; MAP1LC3/LC3, microtubule associated protein 1 light chain 3; PB1, Phox and Bem1 domain; PE, phosphatidylethanolamine; SQSTM1/p62, sequestosome 1; UBA, ubiquitin-associated domain.
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Affiliation(s)
- Päivi Ylä-Anttila
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Soham Gupta
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Maria G Masucci
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
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Rauter T, Burgstaller S, Gottschalk B, Ramadani-Muja J, Bischof H, Hay JC, Graier WF, Malli R. ER-to-Golgi Transport in HeLa Cells Displays High Resilience to Ca 2+ and Energy Stresses. Cells 2020; 9:E2311. [PMID: 33080790 PMCID: PMC7603030 DOI: 10.3390/cells9102311] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/09/2020] [Accepted: 10/16/2020] [Indexed: 02/07/2023] Open
Abstract
One third of all human proteins are either transmembrane or soluble secretory proteins that first target the endoplasmic reticulum (ER). These proteins subsequently leave the ER and enter the Golgi apparatus via ER-Golgi intermediate vesicular structures. Live-cell imaging of cargos fused to fluorescent proteins (FPs) enables the high-resolution visualization and characterization of secretory transport processes. Here, we performed fluorescence time-lapse imaging to assess the Ca2+ and energy dependency of ER-to-Golgi transport in living HeLa cells, a cancer cell model which has been well investigated. Our data revealed that ER-to-Golgi transport remained highly efficient in the absence of ATP-generating substrates, despite clear reductions in cytosolic and mitochondrial ATP levels under these energy stress conditions. However, cell treatment with 2-deoxy-D-glucose (2-DG), which severely diminished subcellular ATP levels, abolished ER-to-Golgi transport. Interestingly, while 2-DG elevated cytosolic Ca2+ levels and reduced long-distance movements of glycosylphosphatidylinositol (GPI)-positive vesicles, robust short-term ER Ca2+ mobilizations, which strongly affected the motility of these vesicles, did not considerably impair ER-to-Golgi transport. In summary, we highlight that ER-to-Golgi transport in HeLa cells remains functional despite high energy and Ca2+ stress levels.
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Affiliation(s)
- Thomas Rauter
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
| | - Sandra Burgstaller
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
- Interfaculty Institute of Cell Biology, University of Tuebingen, Auf der Morgenstelle 15, 72076 Tuebingen, Germany
| | - Benjamin Gottschalk
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
| | - Jeta Ramadani-Muja
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
| | - Helmut Bischof
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany
| | - Jesse C. Hay
- Division of Biological Sciences and Center for Structural and Functional Neuroscience, The University of Montana, 32 Campus Drive, HS 302A, Missoula, MT 59812-4824, USA;
| | - Wolfgang F. Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
- BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
- BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
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6
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Pacheco-Fernandez N, Pakdel M, Blank B, Sanchez-Gonzalez I, Weber K, Tran ML, Hecht TKH, Gautsch R, Beck G, Perez F, Hausser A, Linder S, von Blume J. Nucleobindin-1 regulates ECM degradation by promoting intra-Golgi trafficking of MMPs. J Cell Biol 2020; 219:e201907058. [PMID: 32479594 PMCID: PMC7401813 DOI: 10.1083/jcb.201907058] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 12/29/2019] [Accepted: 05/04/2020] [Indexed: 12/14/2022] Open
Abstract
Matrix metalloproteinases (MMPs) degrade several ECM components and are crucial modulators of cell invasion and tissue organization. Although much has been reported about their function in remodeling ECM in health and disease, their trafficking across the Golgi apparatus remains poorly understood. Here we report that the cis-Golgi protein nucleobindin-1 (NUCB1) is critical for MMP2 and MT1-MMP trafficking along the Golgi apparatus. This process is Ca2+-dependent and is required for invasive MDA-MB-231 cell migration as well as for gelatin degradation in primary human macrophages. Our findings emphasize the importance of NUCB1 as an essential component of MMP transport and its overall impact on ECM remodeling.
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Affiliation(s)
| | | | - Birgit Blank
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | | | - Kathrin Weber
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg, Hamburg, Germany
| | - Mai Ly Tran
- Max Planck Institute of Biochemistry, Martinsried, Germany
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Tobias Karl-Heinz Hecht
- Max Planck Institute of Biochemistry, Martinsried, Germany
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Renate Gautsch
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Gisela Beck
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Franck Perez
- Institute Curie, PSL Research University, Centre National de la Recherche Scientifique, UMR 144, Paris, France
| | - Angelika Hausser
- Institute of Cell Biology and Immunology, University of Stuttgart, Stuttgart, Germany
| | - Stefan Linder
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg, Hamburg, Germany
| | - Julia von Blume
- Max Planck Institute of Biochemistry, Martinsried, Germany
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
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7
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Maki M. Structures and functions of penta-EF-hand calcium-binding proteins and their interacting partners: enigmatic relationships between ALG-2 and calpain-7. Biosci Biotechnol Biochem 2019; 84:651-660. [PMID: 31814542 DOI: 10.1080/09168451.2019.1700099] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The penta-EF-hand (PEF) protein family includes ALG-2 (gene name, PDCD6) and its paralogs as well as classical calpain family members. ALG-2 is a prototypic PEF protein that is widely distributed in eukaryotes and interacts with a variety of proteins in a Ca2+-dependent manner. Mammalian ALG-2 and its interacting partners have various modulatory roles including roles in cell death, signal transduction, membrane repair, ER-to-Golgi vesicular transport, and RNA processing. Some ALG-2-interacting proteins are key factors that function in the endosomal sorting complex required for transport (ESCRT) system. On the other hand, mammalian calpain-7 (CAPN7) lacks the PEF domain but contains two microtubule-interacting and trafficking (MIT) domains in tandem. CAPN7 interacts with a subset of ESCRT-III proteins through the MIT domains and regulates EGF receptor downregulation. Structures and functions of ALG-2 and those of its interacting partners as well as relationships with the calpain family are reviewed in this article.
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Affiliation(s)
- Masatoshi Maki
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
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8
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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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9
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McCaughey J, Stephens DJ. COPII-dependent ER export in animal cells: adaptation and control for diverse cargo. Histochem Cell Biol 2018; 150:119-131. [PMID: 29916038 PMCID: PMC6096569 DOI: 10.1007/s00418-018-1689-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2018] [Indexed: 12/31/2022]
Abstract
The export of newly synthesized proteins from the endoplasmic reticulum is fundamental to the ongoing maintenance of cell and tissue structure and function. After co-translational translocation into the ER, proteins destined for downstream intracellular compartments or secretion from the cell are sorted and packaged into transport vesicles by the COPII coat protein complex. The fundamental discovery and characterization of the pathway has now been augmented by a greater understanding of the role of COPII in diverse aspects of cell function. We now have a deep understanding of how COPII contributes to the trafficking of diverse cargoes including extracellular matrix molecules, developmental signalling proteins, and key metabolic factors such as lipoproteins. Structural and functional studies have shown that the COPII coat is both highly flexible and subject to multiple modes of regulation. This has led to new discoveries defining roles of COPII in development, autophagy, and tissue organization. Many of these newly emerging features of the canonical COPII pathway are placed in a context of procollagen secretion because of the fundamental interest in how a coat complex that typically generates 80-nm transport vesicles can package a cargo reported to be over 300 nm. Here we review the current understanding of COPII and assess the current consensus on its role in packaging diverse cargo proteins.
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Affiliation(s)
- Janine McCaughey
- Cell Biology Laboratories, School of Biochemistry, University Walk, University of Bristol, Bristol, BS8 1TD, UK
| | - David J Stephens
- Cell Biology Laboratories, School of Biochemistry, University Walk, University of Bristol, Bristol, BS8 1TD, UK.
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10
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Takahara T, Inoue K, Arai Y, Kuwata K, Shibata H, Maki M. The calcium-binding protein ALG-2 regulates protein secretion and trafficking via interactions with MISSL and MAP1B proteins. J Biol Chem 2017; 292:17057-17072. [PMID: 28864773 DOI: 10.1074/jbc.m117.800201] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/31/2017] [Indexed: 01/12/2023] Open
Abstract
Mobilization of intracellular calcium is essential for a wide range of cellular processes, including signal transduction, apoptosis, and vesicular trafficking. Several lines of evidence have suggested that apoptosis-linked gene 2 (ALG-2, also known as PDCD6), a calcium-binding protein, acts as a calcium sensor linking calcium levels with efficient vesicular trafficking, especially at the endoplasmic reticulum (ER)-to-Golgi transport step. However, how ALG-2 regulates these processes remains largely unclear. Here, we report that MAPK1-interacting and spindle-stabilizing (MISS)-like (MISSL), a previously uncharacterized protein, interacts with ALG-2 in a calcium-dependent manner. Live-cell imaging revealed that upon a rise in intracellular calcium levels, GFP-tagged MISSL (GFP-MISSL) dynamically relocalizes in a punctate pattern and colocalizes with ALG-2. MISSL knockdown caused disorganization of the components of the ER exit site, the ER-Golgi intermediate compartment, and Golgi. Importantly, knockdown of either MISSL or ALG-2 attenuated the secretion of secreted alkaline phosphatase (SEAP), a model secreted cargo protein, with similar reductions in secretion by single- and double-protein knockdowns, suggesting that MISSL and ALG-2 act in the same pathway to regulate the secretion process. Furthermore, ALG-2 or MISSL knockdown delayed ER-to-Golgi transport of procollagen type I. We also found that ALG-2 and MISSL interact with microtubule-associated protein 1B (MAP1B) and that MAP1B knockdown reverts the reduced secretion of SEAP caused by MISSL or ALG-2 depletion. These results suggest that a change in the intracellular calcium level plays a role in regulation of the secretory pathway via interaction of ALG-2 with MISSL and MAP1B.
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Affiliation(s)
- Terunao Takahara
- From the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, and
| | - Kuniko Inoue
- From the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, and
| | - Yumika Arai
- From the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, and
| | - Keiko Kuwata
- the Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| | - Hideki Shibata
- From the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, and
| | - Masatoshi Maki
- From the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, and
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11
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Kanadome T, Shibata H, Kuwata K, Takahara T, Maki M. The calcium-binding protein ALG-2 promotes endoplasmic reticulum exit site localization and polymerization of Trk-fused gene (TFG) protein. FEBS J 2017; 284:56-76. [PMID: 27813252 DOI: 10.1111/febs.13949] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/28/2016] [Accepted: 11/01/2016] [Indexed: 12/27/2022]
Abstract
Apoptosis-linked gene 2 (ALG-2), which is a gene product of PDCD6, is a 22-kDa Ca2+ -binding protein. Accumulating evidence points to a role for ALG-2 as a Ca2+ -responsive adaptor protein. On binding to Ca2+ , ALG-2 undergoes a conformational change that facilitates its interaction with various proteins. It also forms a homodimer and heterodimer with peflin, a paralog of ALG-2. However, the differences in cellular roles for the ALG-2 homodimer and ALG-2/peflin heterodimer are unclear. In the present study, we found that Trk-fused gene (TFG) protein interacted with the ALG-2 homodimer. Immunostaining analysis revealed that TFG and ALG-2 partially overlapped at endoplasmic reticulum exit sites (ERES), a platform for COPII-mediated protein transport from the endoplasmic reticulum. Time-lapse live-cell imaging demonstrated that both green fluorescent protein-fused TFG and mCherry-fused ALG-2 are recruited to ERES after thapsigargin treatment, which raises intracellular Ca2+ levels. Furthermore, overexpression of ALG-2 induced the accumulation of TFG at ERES. TFG has an ALG-2-binding motif and deletion of the motif decreased TFG binding to ALG-2 and shortened its half-life at ERES, suggesting a critical role for ALG-2 in retaining TFG at ERES. We also demonstrated, by in vitro cross-linking assays, that ALG-2 promoted the polymerization of TFG in a Ca2+ -dependent manner. Collectively, the results suggest that ALG-2 acts as a Ca2+ -sensitive adaptor to concentrate and polymerize TFG at ERES, supporting a potential role for ALG-2 in COPII-dependent trafficking from the endoplasmic reticulum.
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Affiliation(s)
- Takashi Kanadome
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Japan
| | - Hideki Shibata
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Japan
| | - Keiko Kuwata
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Japan
| | - Terunao Takahara
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Japan
| | - Masatoshi Maki
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Japan
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Maki M, Takahara T, Shibata H. Multifaceted Roles of ALG-2 in Ca(2+)-Regulated Membrane Trafficking. Int J Mol Sci 2016; 17:ijms17091401. [PMID: 27571067 PMCID: PMC5037681 DOI: 10.3390/ijms17091401] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/18/2016] [Accepted: 08/19/2016] [Indexed: 12/15/2022] Open
Abstract
ALG-2 (gene name: PDCD6) is a penta-EF-hand Ca2+-binding protein and interacts with a variety of proteins in a Ca2+-dependent fashion. ALG-2 recognizes different types of identified motifs in Pro-rich regions by using different hydrophobic pockets, but other unknown modes of binding are also used for non-Pro-rich proteins. Most ALG-2-interacting proteins associate directly or indirectly with the plasma membrane or organelle membranes involving the endosomal sorting complex required for transport (ESCRT) system, coat protein complex II (COPII)-dependent ER-to-Golgi vesicular transport, and signal transduction from membrane receptors to downstream players. Binding of ALG-2 to targets may induce conformational change of the proteins. The ALG-2 dimer may also function as a Ca2+-dependent adaptor to bridge different partners and connect the subnetwork of interacting proteins.
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Affiliation(s)
- Masatoshi Maki
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
| | - Terunao Takahara
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
| | - Hideki Shibata
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
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