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Arunagiri A, Alam M, Haataja L, Draz H, Alasad B, Samy P, Sadique N, Tong Y, Cai Y, Shakeri H, Fantuzzi F, Ibrahim H, Jang I, Sidarala V, Soleimanpour SA, Satin LS, Otonkoski T, Cnop M, Itkin‐Ansari P, Kaufman RJ, Liu M, Arvan P. Proinsulin folding and trafficking defects trigger a common pathological disturbance of endoplasmic reticulum homeostasis. Protein Sci 2024; 33:e4949. [PMID: 38511500 PMCID: PMC10955614 DOI: 10.1002/pro.4949] [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: 11/13/2023] [Revised: 01/23/2024] [Accepted: 02/14/2024] [Indexed: 03/22/2024]
Abstract
Primary defects in folding of mutant proinsulin can cause dominant-negative proinsulin accumulation in the endoplasmic reticulum (ER), impaired anterograde proinsulin trafficking, perturbed ER homeostasis, diminished insulin production, and β-cell dysfunction. Conversely, if primary impairment of ER-to-Golgi trafficking (which also perturbs ER homeostasis) drives misfolding of nonmutant proinsulin-this might suggest bi-directional entry into a common pathological phenotype (proinsulin misfolding, perturbed ER homeostasis, and deficient ER export of proinsulin) that can culminate in diminished insulin storage and diabetes. Here, we've challenged β-cells with conditions that impair ER-to-Golgi trafficking, and devised an accurate means to assess the relative abundance of distinct folded/misfolded forms of proinsulin using a novel nonreducing SDS-PAGE/immunoblotting protocol. We confirm abundant proinsulin misfolding upon introduction of a diabetogenic INS mutation, or in the islets of db/db mice. Whereas blockade of proinsulin trafficking in Golgi/post-Golgi compartments results in intracellular accumulation of properly-folded proinsulin (bearing native disulfide bonds), impairment of ER-to-Golgi trafficking (regardless whether such impairment is achieved by genetic or pharmacologic means) results in decreased native proinsulin with more misfolded proinsulin. Remarkably, reversible ER-to-Golgi transport defects (such as treatment with brefeldin A or cellular energy depletion) upon reversal quickly restore the ER folding environment, resulting in the disappearance of pre-existing misfolded proinsulin while preserving proinsulin bearing native disulfide bonds. Thus, proper homeostatic balance of ER-to-Golgi trafficking is linked to a more favorable proinsulin folding (as well as trafficking) outcome.
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Affiliation(s)
- Anoop Arunagiri
- Division of Metabolism, Endocrinology & DiabetesUniversity of Michigan Medical CenterAnn ArborMichiganUSA
| | - Maroof Alam
- Division of Metabolism, Endocrinology & DiabetesUniversity of Michigan Medical CenterAnn ArborMichiganUSA
| | - Leena Haataja
- Division of Metabolism, Endocrinology & DiabetesUniversity of Michigan Medical CenterAnn ArborMichiganUSA
| | - Hassan Draz
- Division of Metabolism, Endocrinology & DiabetesUniversity of Michigan Medical CenterAnn ArborMichiganUSA
| | - Bashiyer Alasad
- Division of Metabolism, Endocrinology & DiabetesUniversity of Michigan Medical CenterAnn ArborMichiganUSA
| | - Praveen Samy
- Division of Metabolism, Endocrinology & DiabetesUniversity of Michigan Medical CenterAnn ArborMichiganUSA
| | - Nadeed Sadique
- Division of Metabolism, Endocrinology & DiabetesUniversity of Michigan Medical CenterAnn ArborMichiganUSA
| | - Yue Tong
- ULB Center for Diabetes Research, Medical Faculty; and Division of EndocrinologyErasmus Hospital, Universite Libre de BruxellesBrusselsBelgium
| | - Ying Cai
- ULB Center for Diabetes Research, Medical Faculty; and Division of EndocrinologyErasmus Hospital, Universite Libre de BruxellesBrusselsBelgium
| | - Hadis Shakeri
- ULB Center for Diabetes Research, Medical Faculty; and Division of EndocrinologyErasmus Hospital, Universite Libre de BruxellesBrusselsBelgium
| | - Federica Fantuzzi
- ULB Center for Diabetes Research, Medical Faculty; and Division of EndocrinologyErasmus Hospital, Universite Libre de BruxellesBrusselsBelgium
| | - Hazem Ibrahim
- Stem Cells and Metabolism Research Program, Faculty of MedicineUniversity of HelsinkiHelsinkiFinland
| | - Insook Jang
- Degenerative Diseases ProgramCenter for Genetic Disorders and Aging Research, Sanford Burnham Prebys Medical Discovery InstituteLa JollaCaliforniaUSA
| | - Vaibhav Sidarala
- Division of Metabolism, Endocrinology & DiabetesUniversity of Michigan Medical CenterAnn ArborMichiganUSA
| | - Scott A. Soleimanpour
- Division of Metabolism, Endocrinology & DiabetesUniversity of Michigan Medical CenterAnn ArborMichiganUSA
| | - Leslie S. Satin
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Timo Otonkoski
- Stem Cells and Metabolism Research Program, Faculty of MedicineUniversity of HelsinkiHelsinkiFinland
| | - Miriam Cnop
- ULB Center for Diabetes Research, Medical Faculty; and Division of EndocrinologyErasmus Hospital, Universite Libre de BruxellesBrusselsBelgium
| | - Pamela Itkin‐Ansari
- Development, Aging and Regeneration ProgramCenter for Genetic Disorders and Aging Research, Sanford Burnham Prebys Medical Discovery InstituteLa JollaCaliforniaUSA
| | - Randal J. Kaufman
- Degenerative Diseases ProgramCenter for Genetic Disorders and Aging Research, Sanford Burnham Prebys Medical Discovery InstituteLa JollaCaliforniaUSA
| | - Ming Liu
- Department of Endocrinology and MetabolismTianjin Medical University General HospitalTianjinChina
| | - Peter Arvan
- Division of Metabolism, Endocrinology & DiabetesUniversity of Michigan Medical CenterAnn ArborMichiganUSA
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2
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Ramazanov BR, Parchure A, Di Martino R, Kumar A, Chung M, Kim Y, Griesbeck O, Schwartz MA, Luini A, von Blume J. Calcium flow at ER-TGN contact sites facilitates secretory cargo export. Mol Biol Cell 2024; 35:ar50. [PMID: 38294859 PMCID: PMC11064664 DOI: 10.1091/mbc.e23-03-0099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 01/19/2024] [Accepted: 01/24/2024] [Indexed: 02/01/2024] Open
Abstract
Ca2+ influx into the trans-Golgi Network (TGN) promotes secretory cargo sorting by the Ca2+-ATPase SPCA1 and the luminal Ca2+ binding protein Cab45. Cab45 oligomerizes upon local Ca2+ influx, and Cab45 oligomers sequester and separate soluble secretory cargo from the bulk flow of proteins in the TGN. However, how this Ca2+ flux into the lumen of the TGN is achieved remains mysterious, as the cytosol has a nanomolar steady-state Ca2+ concentration. The TGN forms membrane contact sites (MCS) with the Endoplasmic Reticulum (ER), allowing protein-mediated exchange of molecular species such as lipids. Here, we show that the TGN export of secretory proteins requires the integrity of ER-TGN MCS and inositol 3 phosphate receptor (IP3R)-dependent Ca2+ fluxes in the MCS, suggesting Ca2+ transfer between these organelles. Using an MCS-targeted Ca2+ FRET sensor module, we measure the Ca2+ flow in these sites in real time. These data show that ER-TGN MCS facilitates the Ca2+ transfer required for Ca2+-dependent cargo sorting and export from the TGN, thus solving a fundamental question in cell biology.
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Affiliation(s)
- Bulat R. Ramazanov
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Anup Parchure
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Rosaria Di Martino
- Institute of Biochemistry and Cell Biology, National Research Council, Naples 80131, Italy
| | - Abhishek Kumar
- Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06510
| | - Minhwan Chung
- Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06510
| | - Yeongho Kim
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Oliver Griesbeck
- Max Planck Institute of Neurobiology, Martinsried 82152, Germany
| | - Martin A. Schwartz
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
- Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06510
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511
| | - Alberto Luini
- Institute of Biochemistry and Cell Biology, National Research Council, Naples 80131, Italy
| | - Julia von Blume
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
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3
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Zhang J, Kennedy A, de Melo Jorge DM, Xing L, Reid W, Bui S, Joppich J, Rose M, Ercan S, Tang Q, Tai AW, Wang Y. SARS-CoV-2 remodels the Golgi apparatus to facilitate viral assembly and secretion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2022.03.04.483074. [PMID: 35291301 PMCID: PMC8923104 DOI: 10.1101/2022.03.04.483074] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The COVID-19 pandemic is caused by SARS-CoV-2, an enveloped RNA virus. Despite extensive investigation, the molecular mechanisms for its assembly and secretion remain largely elusive. Here, we show that SARS-CoV-2 infection induces global alterations of the host endomembrane system, including dramatic Golgi fragmentation. SARS-CoV-2 virions are enriched in the fragmented Golgi. Disrupting Golgi function with small molecules strongly inhibits viral infection. Significantly, SARS-CoV-2 infection down-regulates GRASP55 but up-regulates TGN46 protein levels. Surprisingly, GRASP55 expression reduces both viral secretion and spike number on each virion, while GRASP55 depletion displays opposite effects. In contrast, TGN46 depletion only inhibits viral secretion without affecting spike incorporation into virions. TGN46 depletion and GRASP55 expression additively inhibit viral secretion, indicating that they act at different stages. Taken together, we show that SARS-CoV-2 alters Golgi structure and function to control viral assembly and secretion, highlighting the Golgi as a potential therapeutic target for blocking SARS-CoV-2 infection.
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4
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van der Horst D, Kurmasheva N, Marqvorsen MHS, Assil S, Rahimic AHF, Kollmann CF, Silva da Costa L, Wu Q, Zhao J, Cesari E, Iversen MB, Ren F, Jensen TI, Narita R, Schack VR, Zhang BC, Bak RO, Sette C, Fenton RA, Mikkelsen JG, Paludan SR, Olagnier D. SAM68 directs STING signaling to apoptosis in macrophages. Commun Biol 2024; 7:283. [PMID: 38454028 PMCID: PMC10920828 DOI: 10.1038/s42003-024-05969-1] [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: 03/10/2023] [Accepted: 02/23/2024] [Indexed: 03/09/2024] Open
Abstract
DNA is a danger signal sensed by cGAS to engage signaling through STING to activate innate immune functions. The best-studied downstream responses to STING activation include expression of type I interferon and inflammatory genes, but STING also activates other pathways, including apoptosis. Here, we report that STING-dependent induction of apoptosis in macrophages occurs through the intrinsic mitochondrial pathway and is mediated via IRF3 but acts independently of gene transcription. By intersecting four mass spectrometry datasets, we identify SAM68 as crucial for the induction of apoptosis downstream of STING activation. SAM68 is essential for the full activation of apoptosis. Still, it is not required for STING-mediated activation of IFN expression or activation of NF-κB. Mechanistic studies reveal that protein trafficking is required and involves SAM68 recruitment to STING upon activation, with the two proteins associating at the Golgi or a post-Golgi compartment. Collectively, our work identifies SAM68 as a STING-interacting protein enabling induction of apoptosis through this DNA-activated innate immune pathway.
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Affiliation(s)
- Demi van der Horst
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Naziia Kurmasheva
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Mikkel H S Marqvorsen
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Sonia Assil
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Anna H F Rahimic
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Christoph F Kollmann
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Leandro Silva da Costa
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Qi Wu
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Jian Zhao
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Eleonora Cesari
- GSTEP-Organoids Core Facility, IRCCS Fondazione Policlinico Agostino Gemelli, 00168, Rome, Italy
| | - Marie B Iversen
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Fanghui Ren
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Trine I Jensen
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Ryo Narita
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Vivien R Schack
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Bao-Cun Zhang
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Rasmus O Bak
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Claudio Sette
- GSTEP-Organoids Core Facility, IRCCS Fondazione Policlinico Agostino Gemelli, 00168, Rome, Italy
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Hearth, 00168, Rome, Italy
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Jacob G Mikkelsen
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Søren R Paludan
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark.
| | - David Olagnier
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark.
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5
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Li J, Zhang J, Bui S, Ahat E, Kolli D, Reid W, Xing L, Wang Y. Common Assays in Mammalian Golgi Studies. Methods Mol Biol 2022; 2557:303-332. [PMID: 36512224 DOI: 10.1007/978-1-0716-2639-9_20] [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] [Indexed: 12/15/2022]
Abstract
The Golgi is a complex structure characterized by stacks of tightly aligned flat cisternae. In mammalian cells, Golgi stacks often concentrate in the perinuclear region and link together to form a ribbon. This structure is dynamic to accommodate continuous cargo flow in and out of the Golgi in both directions and undergoes morphological changes under physiological and pathological conditions. The fine, stacked Golgi structure makes it difficult to study by conventional light or even super-resolution microscopy. Furthermore, efforts to understand how Golgi structural dynamics impact cellular processes have been slow because of the knowledge gap in the protein machinery that maintains the complex and dynamic Golgi structure. In this method article, we list the common assays used in our research to help new and established researchers select the most appropriate method to properly address their questions.
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Affiliation(s)
- Jie Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jianchao Zhang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Sarah Bui
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Erpan Ahat
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Divya Kolli
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Whitney Reid
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Lijuan Xing
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI, USA.
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6
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Januário YC, Eden J, de Oliveira LS, De Pace R, Tavares LA, da Silva-Januário ME, Apolloni VB, Wilby EL, Altmeyer R, Burgos PV, Corrêa SAL, Gershlick DC, daSilva LLP. Clathrin adaptor AP-1-mediated Golgi export of amyloid precursor protein is crucial for the production of neurotoxic amyloid fragments. J Biol Chem 2022; 298:102172. [PMID: 35753347 PMCID: PMC9352552 DOI: 10.1016/j.jbc.2022.102172] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 11/28/2022] Open
Abstract
One of the hallmarks of Alzheimer's disease is the accumulation of toxic amyloid-β (Aβ) peptides in extracellular plaques. The direct precursor of Aβ is the carboxyl-terminal fragment β (or C99) of the amyloid precursor protein (APP). C99 is detected at elevated levels in Alzheimer's disease brains, and its intracellular accumulation has been linked to early neurotoxicity independently of Aβ. Despite this, the causes of increased C99 levels are poorly understood. Here, we demonstrate that APP interacts with the clathrin vesicle adaptor AP-1 (adaptor protein 1), and we map the interaction sites on both proteins. Using quantitative kinetic trafficking assays, established cell lines and primary neurons, we also show that this interaction is required for the transport of APP from the trans-Golgi network to endosomes. In addition, disrupting AP-1-mediated transport of APP alters APP processing and degradation, ultimately leading to increased C99 production and Aβ release. Our results indicate that AP-1 regulates the subcellular distribution of APP, altering its processing into neurotoxic fragments.
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Affiliation(s)
- Yunan C Januário
- Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Jessica Eden
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Luan S de Oliveira
- Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; School of Pharmacy and Medical Sciences, University of Bradford, Bradford, UK
| | - Raffaella De Pace
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Lucas A Tavares
- Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Mara E da Silva-Januário
- Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Vinícius B Apolloni
- Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Elise L Wilby
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Randolf Altmeyer
- Statslab, Department of Pure Mathematics and Mathematical Statistics, University of Cambridgee, Cambridge, UK
| | - Patricia V Burgos
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile; Center for Aging and Regeneration (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Sonia A L Corrêa
- School of Pharmacy and Medical Sciences, University of Bradford, Bradford, UK; Department of Life Sciences, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK
| | - David C Gershlick
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK.
| | - Luis L P daSilva
- Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
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7
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Tie HC, Mahajan D, Lu L. Visualizing intra-Golgi localization and transport by side-averaging Golgi ministacks. J Biophys Biochem Cytol 2022; 221:213180. [PMID: 35467701 DOI: 10.1083/jcb.202109114] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/03/2021] [Accepted: 04/05/2022] [Indexed: 01/09/2023] Open
Abstract
The mammalian Golgi comprises tightly adjacent and flattened membrane sacs called cisternae. We still do not understand the molecular organization of the Golgi and intra-Golgi transport of cargos. One of the most significant challenges to studying the Golgi is resolving Golgi proteins at the cisternal level under light microscopy. We have developed a side-averaging approach to visualize the cisternal organization and intra-Golgi transport in nocodazole-induced Golgi ministacks. Side-view images of ministacks acquired from Airyscan microscopy are transformed and aligned before intensity normalization and averaging. From side-average images of >30 Golgi proteins, we uncovered the organization of the pre-Golgi, cis, medial, trans, and trans-Golgi network membrane with an unprecedented spatial resolution. We observed the progressive transition of a synchronized cargo wave from the cis to the trans-side of the Golgi. Our data support our previous finding, in which constitutive cargos exit at the trans-Golgi while the secretory targeting to the trans-Golgi network is signal dependent.
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Affiliation(s)
- Hieng Chiong Tie
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Divyanshu Mahajan
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Lei Lu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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8
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Local and substrate-specific S-palmitoylation determines subcellular localization of Gαo. Nat Commun 2022; 13:2072. [PMID: 35440597 PMCID: PMC9018777 DOI: 10.1038/s41467-022-29685-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 03/22/2022] [Indexed: 02/01/2023] Open
Abstract
Peripheral membrane proteins (PMPs) associate with cellular membranes through post-translational modifications like S-palmitoylation. The Golgi apparatus is generally viewed as the transitory station where palmitoyl acyltransferases (PATs) modify PMPs, which are then transported to their ultimate destinations such as the plasma membrane (PM). However, little substrate specificity among the many PATs has been determined. Here we describe the inherent partitioning of Gαo - α-subunit of heterotrimeric Go proteins - to PM and Golgi, independent from Golgi-to-PM transport. A minimal code within Gαo N-terminus governs its compartmentalization and re-coding produces G protein versions with shifted localization. We establish the S-palmitoylation at the outer nuclear membrane assay ("SwissKASH") to probe substrate specificity of PATs in intact cells. With this assay, we show that PATs localizing to different membrane compartments display remarkable substrate selectivity, which is the basis for PMP compartmentalization. Our findings uncover a mechanism governing protein localization and establish the basis for innovative drug discovery.
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9
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Levic DS, Ryan S, Marjoram L, Honeycutt J, Bagwell J, Bagnat M. Distinct roles for luminal acidification in apical protein sorting and trafficking in zebrafish. J Cell Biol 2020; 219:133852. [PMID: 32328632 PMCID: PMC7147097 DOI: 10.1083/jcb.201908225] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 12/20/2019] [Accepted: 01/27/2020] [Indexed: 02/06/2023] Open
Abstract
Epithelial cell physiology critically depends on the asymmetric distribution of channels and transporters. However, the mechanisms targeting membrane proteins to the apical surface are still poorly understood. Here, we performed a visual forward genetic screen in the zebrafish intestine and identified mutants with defective apical targeting of membrane proteins. One of these mutants, affecting the vacuolar H+-ATPase gene atp6ap1b, revealed specific requirements for luminal acidification in apical, but not basolateral, membrane protein sorting and transport. Using a low temperature block assay combined with genetic and pharmacologic perturbation of luminal pH, we monitored transport of newly synthesized membrane proteins from the TGN to apical membrane in live zebrafish. We show that vacuolar H+-ATPase activity regulates sorting of O-glycosylated proteins at the TGN, as well as Rab8-dependent post-Golgi trafficking of different classes of apical membrane proteins. Thus, luminal acidification plays distinct and specific roles in apical membrane biogenesis.
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Affiliation(s)
| | - Sean Ryan
- Department of Cell Biology, Duke University, Durham, NC
| | | | | | | | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC
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10
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Ahmad I, Wilson DW. HSV-1 Cytoplasmic Envelopment and Egress. Int J Mol Sci 2020; 21:ijms21175969. [PMID: 32825127 PMCID: PMC7503644 DOI: 10.3390/ijms21175969] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/14/2020] [Accepted: 08/16/2020] [Indexed: 12/25/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) is a structurally complex enveloped dsDNA virus that has evolved to replicate in human neurons and epithelia. Viral gene expression, DNA replication, capsid assembly, and genome packaging take place in the infected cell nucleus, which mature nucleocapsids exit by envelopment at the inner nuclear membrane then de-envelopment into the cytoplasm. Once in the cytoplasm, capsids travel along microtubules to reach, dock, and envelope at cytoplasmic organelles. This generates mature infectious HSV-1 particles that must then be sorted to the termini of sensory neurons, or to epithelial cell junctions, for spread to uninfected cells. The focus of this review is upon our current understanding of the viral and cellular molecular machinery that enables HSV-1 to travel within infected cells during egress and to manipulate cellular organelles to construct its envelope.
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Affiliation(s)
- Imran Ahmad
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA;
| | - Duncan W. Wilson
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA;
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
- Correspondence:
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11
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Ireland SC, Huang H, Zhang J, Li J, Wang Y. Hydrogen peroxide induces Arl1 degradation and impairs Golgi-mediated trafficking. Mol Biol Cell 2020; 31:1931-1942. [PMID: 32583744 PMCID: PMC7525819 DOI: 10.1091/mbc.e20-01-0063] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 06/02/2020] [Accepted: 06/09/2020] [Indexed: 12/13/2022] Open
Abstract
Reactive oxygen species (ROS)-induced oxidative stress has been associated with diseases such as amyotrophic lateral sclerosis, stroke, and cancer. While the effect of ROS on mitochondria and endoplasmic reticulum (ER) has been well documented, its consequence on the Golgi apparatus is less well understood. In this study, we characterized the Golgi structure and function in HeLa cells after exposure to hydrogen peroxide (H2O2), a reagent commonly used to introduce ROS to cells. Treatment of cells with 1 mM H2O2 for 10 min resulted in the degradation of Arl1 and dissociation of GRIP domain-containing proteins Golgin-97 and Golgin-245 from the trans-Golgi. This effect could be rescued by treatment of cells with a ROS scavenger N-acetyl cysteine or protease inhibitors. Structurally, H2O2 treatment reduced the number of cisternal membranes per Golgi stack, suggesting a loss of trans-Golgi cisternae. Functionally, H2O2 treatment inhibited both anterograde and retrograde protein transport, consistent with the loss of membrane tethers on the trans-Golgi cisternae. This study revealed membrane tethers at the trans-Golgi as novel specific targets of ROS in cells.
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Affiliation(s)
- Stephen C. Ireland
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1085
| | - Haoran Huang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1085
| | - Jianchao Zhang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1085
| | - Jie Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1085
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1085
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI 48109-1085
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12
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Lázaro-Diéguez F, Müsch A. Low Rho activity in hepatocytes prevents apical from basolateral cargo separation during trans-Golgi network to surface transport. Traffic 2020; 21:364-374. [PMID: 32124512 PMCID: PMC7959587 DOI: 10.1111/tra.12725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 12/24/2022]
Abstract
Hepatocytes, the main epithelial cells of the liver, organize their polarized membrane domains differently from ductal epithelia. They also differ in their biosynthetic delivery of single-membrane-spanning and glycophosphatidylinositol-anchored proteins to the apical domain. While ductal epithelia target apical proteins to varying degrees from the trans-Golgi network (TGN) to the apical surface directly, hepatocytes target them first to the basolateral domain, from where they undergo basolateral-to-apical transcytosis. How TGN-to-surface transport differs in both scenarios is unknown. Here, we report that the basolateral detour of a hepatocyte apical protein is due, in part, to low RhoA activity at the TGN, which prevents its segregation from basolateral transport carriers. Activating Rho in hepatocytic cells, which switches their polarity from hepatocytic to ductal, also led to apical-basolateral cargo segregation at the TGN as is typical for ductal cells, affirming a central role for Rho-signaling in different aspects of the hepatocytic polarity phenotype. Nevertheless, Rho-induced cargo segregation was not sufficient to target the apical protein directly; thus, failure to recruit apical targeting machinery also contributes to its indirect itinerary.
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Affiliation(s)
- Francisco Lázaro-Diéguez
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York
| | - Anne Müsch
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York
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13
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Hellerschmied D, Serebrenik YV, Shao L, Burslem GM, Crews CM. Protein folding state-dependent sorting at the Golgi apparatus. Mol Biol Cell 2019; 30:2296-2308. [PMID: 31166830 PMCID: PMC6743468 DOI: 10.1091/mbc.e19-01-0069] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/23/2019] [Accepted: 05/28/2019] [Indexed: 12/14/2022] Open
Abstract
In eukaryotic cells, organelle-specific protein quality control (PQC) is critical for maintaining cellular homeostasis. Despite the Golgi apparatus being the major protein processing and sorting site within the secretory pathway, how it contributes to PQC has remained largely unknown. Using different chemical biology-based protein unfolding systems, we reveal the segregation of unfolded proteins from folded proteins in the Golgi. Quality control (QC) substrates are subsequently exported in distinct carriers, which likely contain unfolded proteins as well as highly oligomerized cargo that mimic protein aggregates. At an additional sorting step, oligomerized proteins are committed to lysosomal degradation, while unfolded proteins localize to the endoplasmic reticulum (ER) and associate with chaperones. These results highlight the existence of checkpoints at which QC substrates are selected for Golgi export and lysosomal degradation. Our data also suggest that the steady-state ER localization of misfolded proteins, observed for several disease-causing mutants, may have different origins.
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Affiliation(s)
| | | | - Lin Shao
- Department of Neuroscience, Yale School of Medicine, New Haven, CT 06520
| | | | - Craig M. Crews
- Department of Molecular, Cellular and Developmental Biology
- Department of Chemistry, Yale University, New Haven, CT 06511
- Department of Pharmacology, Yale University, New Haven, CT 06511
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14
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Dopey1-Mon2 complex binds to dual-lipids and recruits kinesin-1 for membrane trafficking. Nat Commun 2019; 10:3218. [PMID: 31324769 PMCID: PMC6642134 DOI: 10.1038/s41467-019-11056-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 06/14/2019] [Indexed: 11/18/2022] Open
Abstract
Proteins are transported among eukaryotic organelles along the cytoskeleton in membrane carriers. The mechanism regarding the motility of carriers and the positioning of organelles is a fundamental question in cell biology that remains incompletely understood. Here, we find that Dopey1 and Mon2 assemble into a complex and localize to the Golgi, endolysosome and endoplasmic reticulum exit site. The Golgi localization of Dopey1 and Mon2 requires their binding to phosphatidylinositol-4-phosphate and phosphatidic acid, respectively, two lipids known for the biogenesis of membrane carriers and the specification of organelle identities. The N-terminus of Dopey1 further interacts with kinesin-1, a plus-end or centrifugal-direction microtubule motor. Dopey1-Mon2 complex functions as a dual-lipid-regulated cargo-adaptor to recruit kinesin-1 to secretory and endocytic organelles or membrane carriers for centrifugally biased bidirectional transport. Dopey1-Mon2 complex therefore provides an important missing link to coordinate the budding of a membrane carrier and subsequent bidirectional transport along the microtubule. Proteins are transported among eukaryotic organelles along the cytoskeleton in membrane carriers. Here authors find that the Dopey1-Mon2 complex functions as a dual-lipid-regulated cargo-adaptor to recruit kinesin-1 to secretory and endocytic organelles or membrane carriers.
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15
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Rahajeng J, Kuna RS, Makowski SL, Tran TTT, Buschman MD, Li S, Cheng N, Ng MM, Field SJ. Efficient Golgi Forward Trafficking Requires GOLPH3-Driven, PI4P-Dependent Membrane Curvature. Dev Cell 2019; 50:573-585.e5. [PMID: 31231041 PMCID: PMC7583631 DOI: 10.1016/j.devcel.2019.05.038] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 01/22/2019] [Accepted: 05/21/2019] [Indexed: 10/26/2022]
Abstract
Vesicle budding for Golgi-to-plasma membrane trafficking is a key step in secretion. Proteins that induce curvature of the Golgi membrane are predicted to be required, by analogy to vesicle budding from other membranes. Here, we demonstrate that GOLPH3, upon binding to the phosphoinositide PI4P, induces curvature of synthetic membranes in vitro and the Golgi in cells. Moreover, efficient Golgi-to-plasma membrane trafficking critically depends on the ability of GOLPH3 to curve the Golgi membrane. Interestingly, uncoupling of GOLPH3 from its binding partner MYO18A results in extensive curvature of Golgi membranes, producing dramatic tubulation of the Golgi, but does not support forward trafficking. Thus, forward trafficking from the Golgi to the plasma membrane requires the ability of GOLPH3 both to induce Golgi membrane curvature and to recruit MYO18A. These data provide fundamental insight into the mechanism of Golgi trafficking and into the function of the unique Golgi secretory oncoproteins GOLPH3 and MYO18A.
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Affiliation(s)
- Juliati Rahajeng
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ramya S Kuna
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stefanie L Makowski
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Thuy T T Tran
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Matthew D Buschman
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sheng Li
- Department of Medicine, Division of Rheumatology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Norton Cheng
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michelle M Ng
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Seth J Field
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA.
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16
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Moti N, Yu J, Boncompain G, Perez F, Virshup DM. Wnt traffic from endoplasmic reticulum to filopodia. PLoS One 2019; 14:e0212711. [PMID: 30794657 PMCID: PMC6386245 DOI: 10.1371/journal.pone.0212711] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 02/07/2019] [Indexed: 11/26/2022] Open
Abstract
Wnts are a family of secreted palmitoleated glycoproteins that play key roles in cell to cell communication during development and regulate stem cell compartments in adults. Wnt receptors, downstream signaling cascades and target pathways have been extensively studied while less is known about how Wnts are secreted and move from producing cells to receiving cells. We used the synchronization system called Retention Using Selective Hook (RUSH) to study Wnt trafficking from endoplasmic reticulum to Golgi and then to plasma membrane and filopodia in real time. Inhibition of porcupine (PORCN) or knockout of Wntless (WLS) blocked Wnt exit from the ER. Wnt-containing vesicles paused at sub-cortical regions of the plasma membrane before exiting the cell. Wnt-containing vesicles were associated with filopodia extending to adjacent cells. These data visualize and confirm the role of WLS and PORCN in ER exit of Wnts and support the role of filopodia in Wnt signaling.
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Affiliation(s)
- Naushad Moti
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore
| | - Jia Yu
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore
| | - Gaelle Boncompain
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR144 “Cell Biology and Cancer”, Paris, France
| | - Franck Perez
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR144 “Cell Biology and Cancer”, Paris, France
| | - David M. Virshup
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore
- Department of Pediatrics, Duke University, Durham, North Carolina, United States of America
- * E-mail:
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17
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Dimou E, Cosentino K, Platonova E, Ros U, Sadeghi M, Kashyap P, Katsinelos T, Wegehingel S, Noé F, García-Sáez AJ, Ewers H, Nickel W. Single event visualization of unconventional secretion of FGF2. J Cell Biol 2018; 218:683-699. [PMID: 30470711 PMCID: PMC6363455 DOI: 10.1083/jcb.201802008] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 07/07/2018] [Accepted: 11/08/2018] [Indexed: 12/29/2022] Open
Abstract
FGF2 is a cell survival factor secreted by unconventional means. Dimou et al. visualize individual FGF2 translocation events at the plasma membrane by live cell TIRF microscopy, providing insight into the kinetics and the mechanism of this process. FGF2 is exported from cells by an unconventional secretory mechanism. Here, we directly visualized individual FGF2 membrane translocation events at the plasma membrane using live cell TIRF microscopy. This process was dependent on both PI(4,5)P2–mediated recruitment of FGF2 at the inner leaflet and heparan sulfates capturing FGF2 at the outer plasma membrane leaflet. By simultaneous imaging of both FGF2 membrane recruitment and the appearance of FGF2 at the cell surface, we revealed the kinetics of FGF2 membrane translocation in living cells with an average duration of ∼200 ms. Furthermore, we directly demonstrated FGF2 oligomers at the inner leaflet of living cells with a FGF2 dimer being the most prominent species. We propose this dimer to represent a key intermediate in the formation of higher FGF2 oligomers that form membrane pores and put forward a kinetic model explaining the mechanism by which membrane-inserted FGF2 oligomers serve as dynamic translocation intermediates during unconventional secretion of FGF2.
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Affiliation(s)
- Eleni Dimou
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Katia Cosentino
- Interfaculty Institute of Biochemistry, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Evgenia Platonova
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - Uris Ros
- Interfaculty Institute of Biochemistry, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Mohsen Sadeghi
- Department of Mathematics and Computer Science, Free University Berlin, Berlin, Germany
| | - Purba Kashyap
- Institute for Chemistry and Biochemistry, Free University Berlin, Berlin, Germany
| | | | | | - Frank Noé
- Department of Mathematics and Computer Science, Free University Berlin, Berlin, Germany
| | - Ana J García-Sáez
- Interfaculty Institute of Biochemistry, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Helge Ewers
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK .,Institute for Chemistry and Biochemistry, Free University Berlin, Berlin, Germany
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Heidelberg, Germany
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18
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Cellular Protein Kinase D Modulators Play a Role during Multiple Steps of Herpes Simplex Virus 1 Egress. J Virol 2018; 92:JVI.01486-18. [PMID: 30232182 DOI: 10.1128/jvi.01486-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 09/14/2018] [Indexed: 12/12/2022] Open
Abstract
The assembly of new herpes simplex virus 1 (HSV-1) particles takes place in the nucleus. These particles then travel across the two nuclear membranes and acquire a final envelope from a cellular compartment. The contribution of the cell to the release of the virus is, however, little known. We previously demonstrated, using a synchronized infection, that the host protein kinase D and diacylglycerol, a lipid that recruits the kinase to the trans-Golgi network (TGN), promote the release of the virus from that compartment. Given the role this cellular protein plays in the herpes simplex virus 1 life cycle and the many molecules that modulate its activity, we aimed to determine to what extent this virus utilizes the protein kinase D pathway during a nonsynchronized infection. Several molecular protein kinase D (PKD) regulators were targeted by RNA interference and viral production monitored. Surprisingly, many of these modulators negatively impacted the extracellular release of the virus. Overexpression studies, the use of pharmacological reagents, and assays to monitor intracellular lipids implicated in the biology of PKD suggested that these effects were oddly independent of total intracellular diacylglycerol levels. Instead, mapping of the viral intermediates by electron microscopy suggested that some of these modulators could regulate distinct steps along the viral egress pathway, notably nuclear egress. Altogether, this suggests a more complex contribution of PKD to HSV-1 egress than originally anticipated and new research avenues to explore.IMPORTANCE Viruses are obligatory parasites that highjack numerous cellular functions. This is certainly true when it comes to transporting viral particles within the cell. Herpesviruses share the unique property of traveling through the two nuclear membranes by subsequent budding and fusion and acquiring their final envelope from a cellular organelle. Albeit disputed, the overall evidence from many laboratories points to the trans-Golgi network (TGN) as the source of that membrane. Moreover, past findings revealed that the host protein kinase D (PKD) plays an important role at that stage, which is significant given the known implication of that protein in vesicular transport. The present findings suggest that the PKD machinery not only affects the late stages of herpes simplex virus I egress but also modulates earlier steps, such as nuclear egress. This opens up new means to control these viruses.
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19
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Gilder AL, Chapin HC, Padovano V, Hueschen CL, Rajendran V, Caplan MJ. Newly synthesized polycystin-1 takes different trafficking pathways to the apical and ciliary membranes. Traffic 2018; 19:933-945. [PMID: 30125442 PMCID: PMC6237641 DOI: 10.1111/tra.12612] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 08/15/2018] [Accepted: 08/15/2018] [Indexed: 12/26/2022]
Abstract
Mutations in the genes encoding polycystin-1 (PC1) and polycystin 2 (PC2) cause autosomal dominant polycystic kidney disease. These transmembrane proteins colocalize in the primary cilia of renal epithelial cells, where they may participate in sensory processes. PC1 is also found in the apical membrane when expressed in cultured epithelial cells. PC1 undergoes autocatalytic cleavage, producing an extracellular N-terminal fragment that remains noncovalently attached to the transmembrane C-terminus. Exposing cells to alkaline solutions elutes the N-terminal fragment while the C-terminal fragment is retained in the cell membrane. Utilizing this observation, we developed a "strip-recovery" synchronization protocol to study PC1 trafficking in polarized LLC-PK1 renal epithelial cells. Following alkaline strip, a new cohort of PC1 repopulates the cilia within 30 minutes, while apical delivery of PC1 was not detectable until 3 hours. Brefeldin A (BFA) blocked apical PC1 delivery, while ciliary delivery of PC1 was BFA insensitive. Incubating cells at 20°C to block trafficking out of the trans-Golgi network also inhibits apical but not ciliary delivery. These results suggest that newly synthesized PC1 takes distinct pathways to the ciliary and apical membranes. Ciliary PC1 appears to by-pass BFA sensitive Golgi compartments, while apical delivery of PC1 traverses these compartments.
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Affiliation(s)
- Allison L Gilder
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut
| | - Hannah C Chapin
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut
| | - Valeria Padovano
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut
| | - Christina L Hueschen
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Vanathy Rajendran
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Michael J Caplan
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut.,Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
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20
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Harris MT, Hussain SS, Inouye CM, Castle AM, Castle JD. Reinterpretation of the localization of the ATP binding cassette transporter ABCG1 in insulin-secreting cells and insights regarding its trafficking and function. PLoS One 2018; 13:e0198383. [PMID: 30235209 PMCID: PMC6147399 DOI: 10.1371/journal.pone.0198383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/04/2018] [Indexed: 01/08/2023] Open
Abstract
The ABC transporter ABCG1 contributes to the regulation of cholesterol efflux from cells and to the distribution of cholesterol within cells. We showed previously that ABCG1 deficiency inhibits insulin secretion by pancreatic beta cells and, based on its immunolocalization to insulin granules, proposed its essential role in forming granule membranes that are enriched in cholesterol. While we confirm elsewhere that ABCG1, alongside ABCA1 and oxysterol binding protein OSBP, supports insulin granule formation, the aim here is to clarify the localization of ABCG1 within insulin-secreting cells and to provide added insight regarding ABCG1's trafficking and sites of function. We show that stably expressed GFP-tagged ABCG1 closely mimics the distribution of endogenous ABCG1 in pancreatic INS1 cells and accumulates in the trans-Golgi network (TGN), endosomal recycling compartment (ERC) and on the cell surface but not on insulin granules, early or late endosomes. Notably, ABCG1 is short-lived, and proteasomal and lysosomal inhibitors both decrease its degradation. Following blockade of protein synthesis, GFP-tagged ABCG1 first disappears from the ER and TGN and later from the ERC and plasma membrane. In addition to aiding granule formation, our findings raise the prospect that ABCG1 may act beyond the TGN to regulate activities involving the endocytic pathway, especially as the amount of transferrin receptor is increased in ABCG1-deficient cells. Thus, ABCG1 may function at multiple intracellular sites and the plasma membrane as a roving sensor and modulator of cholesterol distribution, membrane trafficking and cholesterol efflux.
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Affiliation(s)
- Megan T. Harris
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Syed Saad Hussain
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Candice M. Inouye
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Anna M. Castle
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - J. David Castle
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
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21
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Saraste J, Marie M. Intermediate compartment (IC): from pre-Golgi vacuoles to a semi-autonomous membrane system. Histochem Cell Biol 2018; 150:407-430. [PMID: 30173361 PMCID: PMC6182704 DOI: 10.1007/s00418-018-1717-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2018] [Indexed: 12/19/2022]
Abstract
Despite its discovery more than three decades ago and well-established role in protein sorting and trafficking in the early secretory pathway, the intermediate compartment (IC) has remained enigmatic. The prevailing view is that the IC evolved as a specialized organelle to mediate long-distance endoplasmic reticulum (ER)–Golgi communication in metazoan cells, but is lacking in other eukaryotes, such as plants and fungi. However, this distinction is difficult to reconcile with the high conservation of the core machineries that regulate early secretory trafficking from yeast to man. Also, it has remained unclear whether the pleiomorphic IC components—vacuoles, tubules and vesicles—represent transient transport carriers or building blocks of a permanent pre-Golgi organelle. Interestingly, recent studies have revealed that the IC maintains its compositional, structural and spatial properties throughout the cell cycle, supporting a model that combines the dynamic and stable aspects of the organelle. Moreover, the IC has been assigned novel functions, such as cell signaling, Golgi-independent trafficking and autophagy. The emerging permanent nature of the IC and its connections with the centrosome and the endocytic recycling system encourage reconsideration of its relationship with the Golgi ribbon, role in Golgi biogenesis and ubiquitous presence in eukaryotic cells.
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Affiliation(s)
- Jaakko Saraste
- Department of Biomedicine and Molecular Imaging Center (MIC), University of Bergen, Jonas Lies vei 91, 5009, Bergen, Norway.
| | - Michaël Marie
- Department of Biomedicine and Molecular Imaging Center (MIC), University of Bergen, Jonas Lies vei 91, 5009, Bergen, Norway
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22
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Gilbert CE, Sztul E, Machamer CE. Commonly used trafficking blocks disrupt ARF1 activation and the localization and function of specific Golgi proteins. Mol Biol Cell 2018; 29:937-947. [PMID: 29467256 PMCID: PMC5896932 DOI: 10.1091/mbc.e17-11-0622] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cold temperature blocks used to synchronize protein trafficking inhibit GBF1 function, leading to a decrease in ARF1-GTP levels and mislocalization of the ARF1 effector golgin-160. Several other, but not all, Golgi proteins including ARL1 also mislocalize. ARF1 activity and golgin-160 localization require more than 30 min to recover from these blocks. ADP-ribosylation factor (ARF) proteins are key regulators of the secretory pathway. ARF1, through interacting with its effectors, regulates protein trafficking by facilitating numerous events at the Golgi. One unique ARF1 effector is golgin-160, which promotes the trafficking of only a specific subset of cargo proteins through the Golgi. While studying this role of golgin-160, we discovered that commonly used cold temperature blocks utilized to synchronize cargo trafficking (20 and 16°C) caused golgin-160 dispersal from Golgi membranes. Here, we show that the loss of golgin-160 localization correlates with a decrease in the levels of activated ARF1, and that golgin-160 dispersal can be prevented by expression of a GTP-locked ARF1 mutant. Overexpression of the ARF1 activator Golgi brefeldin A–resistant guanine nucleotide exchange factor 1 (GBF1) did not prevent golgin-160 dispersal, suggesting that GBF1 may be nonfunctional at lower temperatures. We further discovered that several other Golgi resident proteins had altered localization at lower temperatures, including proteins recruited by ARF-like GTPase 1 (ARL1), a small GTPase that also became dispersed in the cold. Although cold temperature blocks are useful for synchronizing cargo trafficking through the Golgi, our data indicate that caution must be taken when interpreting results from these assays.
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Affiliation(s)
- Catherine E Gilbert
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Elizabeth Sztul
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35924
| | - Carolyn E Machamer
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
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23
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Bowen AB, Bourke AM, Hiester BG, Hanus C, Kennedy MJ. Golgi-independent secretory trafficking through recycling endosomes in neuronal dendrites and spines. eLife 2017; 6:27362. [PMID: 28875935 PMCID: PMC5624785 DOI: 10.7554/elife.27362] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/30/2017] [Indexed: 12/13/2022] Open
Abstract
Neurons face the challenge of regulating the abundance, distribution and repertoire of integral membrane proteins within their immense, architecturally complex dendritic arbors. While the endoplasmic reticulum (ER) supports dendritic translation, most dendrites lack the Golgi apparatus (GA), an essential organelle for conventional secretory trafficking. Thus, whether secretory cargo is locally trafficked in dendrites through a non-canonical pathway remains a fundamental question. Here we define the dendritic trafficking itinerary for key synaptic molecules in rat cortical neurons. Following ER exit, the AMPA-type glutamate receptor GluA1 and neuroligin 1 undergo spatially restricted entry into the dendritic secretory pathway and accumulate in recycling endosomes (REs) located in dendrites and spines before reaching the plasma membrane. Surprisingly, GluA1 surface delivery occurred even when GA function was disrupted. Thus, in addition to their canonical role in protein recycling, REs also mediate forward secretory trafficking in neuronal dendrites and spines through a specialized GA-independent trafficking network. All cells must produce, sort and deliver molecular building blocks to the right places at the right time and in appropriate amounts. This is particularly important for neurons, which are the largest and most structurally complex cells in the body. A typical neuron consists of a cell body covered in branches called dendrites, plus a single cable-like structure known as an axon. Dendrites receive inputs from other neurons and relay the information to the cell body in the form of electrical signals. The cell body processes these electrical signals and the resulting signals then travel along the axon to terminals at the far-end. The axon terminals in turn pass the signals on to the dendrites of other neurons via junctions called synapses. For synapses to work correctly, the membranes surrounding the dendrites need to contain receptor proteins that can detect incoming signals. These proteins must be continually replenished, raising the question of how newly made receptor molecules are shuttled to the appropriate locations within the dendrites. A series of compartments called the Golgi complex play an important role in processing newly-made proteins in many different types of cells. As proteins pass through the Golgi, enzymes within the tunnel walls modify the proteins by adding or removing molecular groups. Therefore, it has been suggested that the route that the synapse receptor proteins take through the neuron to reach the dendrites always includes a visit to the Golgi. However, the Golgi complex in neurons is mostly confined to the cell body, raising the question of whether proteins that are locally produced within dendrites can make the journey to nearby synapses without visiting the Golgi complex. Bowen et al. used a microscope to follow the movements of synapse receptor proteins through neurons grown in a dish. The experiments show that proteins destined for the dendrites make a number of stops after leaving the cell body. However, some synaptic proteins reach the dendrites without passing through the Golgi at all, suggesting neurons are much less dependent on the Golgi to process newly-made proteins than other types of cells. Genetic mutations that prevent proteins from finding their way to their required destinations, or that disrupt the work of enzymes inside trafficking stations like the Golgi, cause numerous human diseases. Understanding how proteins travel to specific destinations inside healthy cells should also help reveal what happens when this process fails.
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Affiliation(s)
- Aaron B Bowen
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, United States
| | - Ashley M Bourke
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, United States
| | - Brian G Hiester
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, United States
| | - Cyril Hanus
- Center for Psychiatry and Neurosciences, University Paris-Descartes, Paris, France
| | - Matthew J Kennedy
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, United States
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24
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Rodepeter FR, Wiegand S, Lüers HG, Bonaterra GA, Lowe AW, Bette M, Jacob R, Mandic R. Indication for differential sorting of the rat v-SNARE splice isoforms VAMP-1a and -1b. Biochem Cell Biol 2017; 95:500-509. [PMID: 28314111 DOI: 10.1139/bcb-2016-0184] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins are essential constituents of the intracellular trafficking machinery. The variable C-terminus in the 2 rat VAMP-1 splice isoforms VAMP-1a and -1b potentially acts as a sorting signal, because similar changes at the C-terminal end of a human VAMP-1 splice isoform resulted in its sorting to mitochondria. To evaluate the differences in the subcellular localization of these two v-SNARE proteins, VAMP-1a and -1b proteins tagged with green fluorescent protein (GFP) and red fluorescent protein (RFP) were expressed in HeLa, COS-7, and MDCK cells and evaluated by conventional confocal as well as total internal reflection fluorescence microscopy. Regions consistent with the endoplasmic reticulum and Golgi apparatus demonstrated a major overlap of both signals. In the periphery, vesicular structures were observed that mainly expressed one of the 2 isoforms. Within our experimental settings, we could not observe sorting of any of the 2 isoforms to mitochondria or peroxisomes, whereas both isoforms were found expressed in a minor subset of singular vesicles, which sporadically appeared to co-localize with the exocyst marker EXOC3/Sec6. Because vesicular structures were seen that expressed only one of the two splice variants, it is possible that VAMP-1a and VAMP-1b are sorted to distinct cellular compartments that require further characterization.
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Affiliation(s)
- Fiona R Rodepeter
- a Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Giessen and Marburg, Campus Marburg, 3.BA, Room +3/08070, Baldingerstrasse, D-35033 Marburg, Germany
| | - Susanne Wiegand
- a Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Giessen and Marburg, Campus Marburg, 3.BA, Room +3/08070, Baldingerstrasse, D-35033 Marburg, Germany
| | - Hans-Georg Lüers
- b Department of Cell Biology, Institute of Anatomy and Cell Biology, Philipps-Universität, Marburg, Germany
| | - Gabriel A Bonaterra
- c Department of Medical Cell Biology, Philipps-Universität, Marburg, Germany
| | - Anson W Lowe
- d Department of Medicine, Stanford University, Stanford, CA, USA
| | - Michael Bette
- e Department of Molecular Neuroscience, Institute of Anatomy and Cell Biology, Philipps-Universität, Marburg, Germany
| | - Ralf Jacob
- f Institute of Cell Biology and Cell Pathology, Philipps-Universität, Marburg, Germany
| | - Robert Mandic
- a Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Giessen and Marburg, Campus Marburg, 3.BA, Room +3/08070, Baldingerstrasse, D-35033 Marburg, Germany
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25
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Stoops EH, Hull M, Caplan MJ. Newly synthesized and recycling pools of the apical protein gp135 do not occupy the same compartments. Traffic 2016; 17:1272-1285. [PMID: 27649479 PMCID: PMC5123909 DOI: 10.1111/tra.12449] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 09/15/2016] [Accepted: 09/15/2016] [Indexed: 12/19/2022]
Abstract
Polarized epithelial cells sort newly synthesized and recycling plasma membrane proteins into distinct trafficking pathways directed to either the apical or basolateral membrane domains. While the trans-Golgi network is a well-established site of protein sorting, increasing evidence indicates a key role for endosomes in the initial trafficking of newly synthesized proteins. Both basolateral and apical proteins have been shown to traverse endosomes en route to the plasma membrane. In particular, apical proteins traffic through either subapical early or recycling endosomes. Here we use the SNAP tag system to analyze the trafficking of the apical protein gp135, also known as podocalyxin. We show that newly synthesized gp135 traverses the apical recycling endosome, but not the apical early endosomes (AEEs). In contrast, post-endocytic gp135 is delivered to the AEE before recycling back to the apical membrane. The pathways pursued by the newly synthesized and recycling gp135 populations do not detectably intersect, demonstrating that the biosynthetic and post-endocytic pools of this protein are subjected to distinct sorting processes.
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Affiliation(s)
- Emily H Stoops
- Department of Cellular and Molecular Physiology and Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Michael Hull
- Department of Cellular and Molecular Physiology and Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Michael J Caplan
- Department of Cellular and Molecular Physiology and Department of Cell Biology, Yale University School of Medicine, New Haven, CT
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26
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Hanus C, Geptin H, Tushev G, Garg S, Alvarez-Castelao B, Sambandan S, Kochen L, Hafner AS, Langer JD, Schuman EM. Unconventional secretory processing diversifies neuronal ion channel properties. eLife 2016; 5:e20609. [PMID: 27677849 PMCID: PMC5077297 DOI: 10.7554/elife.20609] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Accepted: 09/22/2016] [Indexed: 01/01/2023] Open
Abstract
N-glycosylation - the sequential addition of complex sugars to adhesion proteins, neurotransmitter receptors, ion channels and secreted trophic factors as they progress through the endoplasmic reticulum and the Golgi apparatus - is one of the most frequent protein modifications. In mammals, most organ-specific N-glycosylation events occur in the brain. Yet, little is known about the nature, function and regulation of N-glycosylation in neurons. Using imaging, quantitative immunoblotting and mass spectrometry, we show that hundreds of neuronal surface membrane proteins are core-glycosylated, resulting in the neuronal membrane displaying surprisingly high levels of glycosylation profiles that are classically associated with immature intracellular proteins. We report that while N-glycosylation is generally required for dendritic development and glutamate receptor surface expression, core-glycosylated proteins are sufficient to sustain these processes, and are thus functional. This atypical glycosylation of surface neuronal proteins can be attributed to a bypass or a hypo-function of the Golgi apparatus. Core-glycosylation is regulated by synaptic activity, modulates synaptic signaling and accelerates the turnover of GluA2-containing glutamate receptors, revealing a novel mechanism that controls the composition and sensing properties of the neuronal membrane.
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Affiliation(s)
- Cyril Hanus
- Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Helene Geptin
- Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Georgi Tushev
- Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Sakshi Garg
- Max Planck Institute for Brain Research, Frankfurt, Germany
| | | | | | - Lisa Kochen
- Max Planck Institute for Brain Research, Frankfurt, Germany
| | | | - Julian D Langer
- Max Planck Institute for Brain Research, Frankfurt, Germany
- Max Planck Institute for Biophysics, Frankfurt, Germany
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt, Germany
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27
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Ye QH, Zhu WW, Zhang JB, Qin Y, Lu M, Lin GL, Guo L, Zhang B, Lin ZH, Roessler S, Forgues M, Jia HL, Lu L, Zhang XF, Lian BF, Xie L, Dong QZ, Tang ZY, Wang XW, Qin LX. GOLM1 Modulates EGFR/RTK Cell-Surface Recycling to Drive Hepatocellular Carcinoma Metastasis. Cancer Cell 2016; 30:444-458. [PMID: 27569582 PMCID: PMC5021625 DOI: 10.1016/j.ccell.2016.07.017] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Revised: 06/27/2016] [Accepted: 07/26/2016] [Indexed: 12/11/2022]
Abstract
The mechanism of cancer metastasis remains poorly understood. Using gene profiling of hepatocellular carcinoma (HCC) tissues, we have identified GOLM1 as a leading gene relating to HCC metastasis. GOLM1 expression is correlated with early recurrence, metastasis, and poor survival of HCC patients. Both gain- and loss-of-function studies determine that GOLM1 acts as a key oncogene by promoting HCC growth and metastasis. It selectively interacts with epidermal growth factor receptor (EGFR) and serves as a specific cargo adaptor to assist EGFR/RTK anchoring on the trans-Golgi network (TGN) and recycling back to the plasma membrane, leading to prolonged activation of the downstream kinases. These findings reveal the functional role of GOLM1, a Golgi-related protein, in EGFR/RTK recycling and metastatic progression of HCC.
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Affiliation(s)
- Qing-Hai Ye
- Liver Cancer Institute, Fudan University, Shanghai 200032, China
| | - Wen-Wei Zhu
- Liver Cancer Institute, Fudan University, Shanghai 200032, China; Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute, Fudan University, 12 Urumqi Road (M), Shanghai 200040, China
| | - Ju-Bo Zhang
- Liver Cancer Institute, Fudan University, Shanghai 200032, China; Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Yi Qin
- Institutes of Biomedical Science, Fudan University, Shanghai 200032, China; Department of Pancreatic and Hepatobiliary Surgery, Fudan University Shanghai Cancer Center, Shanghai 200032, China
| | - Ming Lu
- Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute, Fudan University, 12 Urumqi Road (M), Shanghai 200040, China
| | - Guo-Ling Lin
- Liver Cancer Institute, Fudan University, Shanghai 200032, China
| | - Lei Guo
- Liver Cancer Institute, Fudan University, Shanghai 200032, China
| | - Bo Zhang
- Liver Cancer Institute, Fudan University, Shanghai 200032, China
| | - Zhen-Hai Lin
- Liver Cancer Institute, Fudan University, Shanghai 200032, China
| | - Stephanie Roessler
- Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA; Institute of Pathology, University Hospital Heidelberg 69120 Heidelberg, Germany
| | - Marshonna Forgues
- Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Hu-Liang Jia
- Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute, Fudan University, 12 Urumqi Road (M), Shanghai 200040, China
| | - Lu Lu
- Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute, Fudan University, 12 Urumqi Road (M), Shanghai 200040, China
| | - Xiao-Fei Zhang
- Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute, Fudan University, 12 Urumqi Road (M), Shanghai 200040, China
| | - Bao-Feng Lian
- Shanghai Center for Bioinformatics Technology, Shanghai 201203, China
| | - Lu Xie
- Shanghai Center for Bioinformatics Technology, Shanghai 201203, China
| | - Qiong-Zhu Dong
- Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute, Fudan University, 12 Urumqi Road (M), Shanghai 200040, China; Institutes of Biomedical Science, Fudan University, Shanghai 200032, China
| | - Zhao-You Tang
- Liver Cancer Institute, Fudan University, Shanghai 200032, China; Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute, Fudan University, 12 Urumqi Road (M), Shanghai 200040, China
| | - Xin Wei Wang
- Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
| | - Lun-Xiu Qin
- Liver Cancer Institute, Fudan University, Shanghai 200032, China; Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute, Fudan University, 12 Urumqi Road (M), Shanghai 200040, China; Institutes of Biomedical Science, Fudan University, Shanghai 200032, China.
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28
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Yonemura Y, Li X, Müller K, Krämer A, Atigbire P, Mentrup T, Feuerhake T, Kroll T, Shomron O, Nohl R, Arndt HD, Hoischen C, Hemmerich P, Hirschberg K, Kaether C. Inhibition of cargo export at ER exit sites and the trans-Golgi network by the secretion inhibitor FLI-06. J Cell Sci 2016; 129:3868-3877. [PMID: 27587840 DOI: 10.1242/jcs.186163] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 08/25/2016] [Indexed: 12/21/2022] Open
Abstract
Export out of the endoplasmic reticulum (ER) involves the Sar1 and COPII machinery acting at ER exit sites (ERES). Whether and how cargo proteins are recruited upstream of Sar1 and COPII is unclear. Two models are conceivable, a recruitment model where cargo is actively transported through a transport factor and handed over to the Sar1 and COPII machinery in ERES, and a capture model, where cargo freely diffuses into ERES where it is captured by the Sar1 and COPII machinery. Using the novel secretion inhibitor FLI-06, we show that recruitment of the cargo VSVG to ERES is an active process upstream of Sar1 and COPII. Applying FLI-06 before concentration of VSVG in ERES completely abolishes its recruitment. In contrast, applying FLI-06 after VSVG concentration in ERES does not lead to dispersal of the concentrated VSVG, arguing that it inhibits recruitment to ERES as opposed to capture in ERES. FLI-06 also inhibits export out of the trans-Golgi network (TGN), suggesting that similar mechanisms might orchestrate cargo selection and concentration at the ER and TGN. FLI-06 does not inhibit autophagosome biogenesis and the ER-peroxisomal transport route, suggesting that these rely on different mechanisms.
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Affiliation(s)
- Yoji Yonemura
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Jena 07745, Germany
| | - Xiaolin Li
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Jena 07745, Germany
| | - Katja Müller
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Jena 07745, Germany
| | - Andreas Krämer
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Jena 07745, Germany
| | - Paul Atigbire
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Jena 07745, Germany
| | - Torben Mentrup
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Jena 07745, Germany
| | - Talitha Feuerhake
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Jena 07745, Germany
| | - Torsten Kroll
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Jena 07745, Germany
| | - Olga Shomron
- Pathology Department, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Richard Nohl
- Lehrstuhl für organische Chemie I, Friedrich-Schiller Universität, Jena 07743, Germany
| | - Hans-Dieter Arndt
- Lehrstuhl für organische Chemie I, Friedrich-Schiller Universität, Jena 07743, Germany
| | - Christian Hoischen
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Jena 07745, Germany
| | - Peter Hemmerich
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Jena 07745, Germany
| | - Koret Hirschberg
- Pathology Department, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Christoph Kaether
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Jena 07745, Germany
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29
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Sphingomyelin is sorted at the trans Golgi network into a distinct class of secretory vesicle. Proc Natl Acad Sci U S A 2016; 113:6677-82. [PMID: 27247384 DOI: 10.1073/pnas.1602875113] [Citation(s) in RCA: 243] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One of the principal functions of the trans Golgi network (TGN) is the sorting of proteins into distinct vesicular transport carriers that mediate secretion and interorganelle trafficking. Are lipids also sorted into distinct TGN-derived carriers? The Golgi is the principal site of the synthesis of sphingomyelin (SM), an abundant sphingolipid that is transported. To address the specificity of SM transport to the plasma membrane, we engineered a natural SM-binding pore-forming toxin, equinatoxin II (Eqt), into a nontoxic reporter termed Eqt-SM and used it to monitor intracellular trafficking of SM. Using quantitative live cell imaging, we found that Eqt-SM is enriched in a subset of TGN-derived secretory vesicles that are also enriched in a glycophosphatidylinositol-anchored protein. In contrast, an integral membrane secretory protein (CD8α) is not enriched in these carriers. Our results demonstrate the sorting of native SM at the TGN and its transport to the plasma membrane by specific carriers.
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30
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Treyer A, Pujato M, Pechuan X, Müsch A. Iterative sorting of apical and basolateral cargo in Madin-Darby canine kidney cells. Mol Biol Cell 2016; 27:2259-71. [PMID: 27226480 PMCID: PMC4945143 DOI: 10.1091/mbc.e16-02-0096] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/19/2016] [Indexed: 01/21/2023] Open
Abstract
A novel assay quantitatively distinguishes different cargo pairs by their degree of colocalization at the TGN and the evolution of colocalization during their TGN-to-surface transport. Apical NTRp75 and basolateral VSVG in MDCK cells undergo continuous sorting between TGN exit and surface arrival. For several decades, the trans-Golgi network (TGN) was considered the most distal stop and hence the ultimate protein-sorting station for distinct apical and basolateral transport carriers that reach their respective surface domains in the direct trafficking pathway. However, recent reports of apical and basolateral cargoes traversing post-Golgi compartments accessible to endocytic ligands before their arrival at the cell surface and the post-TGN breakup of large pleomorphic membrane fragments that exit the Golgi region toward the surface raised the possibility that compartments distal to the TGN mediate or contribute to biosynthetic sorting. Here we describe the development of a novel assay that quantitatively distinguishes different cargo pairs by their degree of colocalization at the TGN and by the evolution of colocalization during their TGN-to-surface transport. Keys to the high resolution of our approach are 1) conversion of perinuclear organelle clustering into a two-dimensional microsomal spread and 2) identification of TGN and post-TGN cargo without the need for a TGN marker that universally cosegregates with all cargo. Using our assay, we provide the first evidence that apical NTRp75 and basolateral VSVG in Madin–Darby canine kidney cells still undergo progressive sorting after they exit the TGN toward the cell surface.
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Affiliation(s)
- Aleksandr Treyer
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Mario Pujato
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461 Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Ximo Pechuan
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Anne Müsch
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461
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31
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Abraham O, Gotliv K, Parnis A, Boncompain G, Perez F, Cassel D. Control of protein trafficking by reversible masking of transport signals. Mol Biol Cell 2016; 27:1310-9. [PMID: 26941332 PMCID: PMC4831884 DOI: 10.1091/mbc.e15-07-0472] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 02/23/2016] [Indexed: 02/06/2023] Open
Abstract
A system for controlled trafficking of proteins is based on modifying the streptavidin-binding peptide with trafficking signals and appending it to reporter proteins. Coexpression with streptavidin results in signal masking, which is reversed upon biotin addition. Systems that allow the control of protein traffic between subcellular compartments have been valuable in elucidating trafficking mechanisms. Most current approaches rely on ligand or light-controlled dimerization, which results in either retardation or enhancement of the transport of a reporter. We developed an alternative approach for trafficking regulation that we term “controlled unmasking of targeting elements” (CUTE). Regulated trafficking is achieved by reversible masking of the signal that directs the reporter to its target organelle, relying on the streptavidin–biotin system. The targeting signal is generated within or immediately after a 38–amino acid streptavidin-binding peptide (SBP) that is appended to the reporter. The binding of coexpressed streptavidin to SBP causes signal masking, whereas addition of biotin causes complex dissociation and triggers protein transport to the target organelle. We demonstrate the application of this approach to the control of nuclear and peroxisomal protein import and the generation of biotin-dependent trafficking through the endocytic and COPI systems. By simultaneous masking of COPI and endocytic signals, we were able to generate a synthetic pathway for efficient transport of a reporter from the plasma membrane to the endoplasmic reticulum.
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Affiliation(s)
- Omer Abraham
- Department of Biology, Technion, Haifa 320003, Israel
| | - Karnit Gotliv
- Department of Biology, Technion, Haifa 320003, Israel
| | - Anna Parnis
- Department of Biology, Technion, Haifa 320003, Israel
| | - Gaelle Boncompain
- Institut Curie, Centre de Recherche, PSL Research University, and CNRS, UMR144, Paris 75248, France
| | - Franck Perez
- Institut Curie, Centre de Recherche, PSL Research University, and CNRS, UMR144, Paris 75248, France
| | - Dan Cassel
- Department of Biology, Technion, Haifa 320003, Israel
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32
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Fra A, Cosmi F, Ordoñez A, Berardelli R, Perez J, Guadagno NA, Corda L, Marciniak SJ, Lomas DA, Miranda E. Polymers of Z α1-antitrypsin are secreted in cell models of disease. Eur Respir J 2016; 47:1005-9. [DOI: 10.1183/13993003.00940-2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 12/15/2015] [Indexed: 11/05/2022]
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Abstract
In mature neurons AMPA receptors cluster at excitatory synapses primarily on dendritic spines, whereas GABAA receptors cluster at inhibitory synapses mainly on the soma and dendritic shafts. The molecular mechanisms underlying the precise sorting of these receptors remain unclear. By directly studying the constitutive exocytic vesicles of AMPA and GABAA receptors in vitro and in vivo, we demonstrate that they are initially sorted into different vesicles in the Golgi apparatus and inserted into distinct domains of the plasma membrane. These insertions are dependent on distinct Rab GTPases and SNARE complexes. The insertion of AMPA receptors requires SNAP25-syntaxin1A/B-VAMP2 complexes, whereas insertion of GABAA receptors relies on SNAP23-syntaxin1A/B-VAMP2 complexes. These SNARE complexes affect surface targeting of AMPA or GABAA receptors and synaptic transmission. Our studies reveal vesicular sorting mechanisms controlling the constitutive exocytosis of AMPA and GABAA receptors, which are critical for the regulation of excitatory and inhibitory responses in neurons.
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34
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Tie HC, Mahajan D, Chen B, Cheng L, VanDongen AMJ, Lu L. A novel imaging method for quantitative Golgi localization reveals differential intra-Golgi trafficking of secretory cargoes. Mol Biol Cell 2016; 27:848-61. [PMID: 26764092 PMCID: PMC4803310 DOI: 10.1091/mbc.e15-09-0664] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 01/07/2016] [Indexed: 12/02/2022] Open
Abstract
A novel imaging-based method is introduced to quantitatively localize Golgi proteins at nanometer resolution. The method reveals different intra-Golgi trafficking of secretory cargoes. Cellular functions of the Golgi are determined by the unique distribution of its resident proteins. Currently, electron microscopy is required for the localization of a Golgi protein at the sub-Golgi level. We developed a quantitative sub-Golgi localization method based on centers of fluorescence masses of nocodazole-induced Golgi ministacks under conventional optical microscopy. Our method is rapid, convenient, and quantitative, and it yields a practical localization resolution of ∼30 nm. The method was validated by the previous electron microscopy data. We quantitatively studied the intra-Golgi trafficking of synchronized secretory membrane cargoes and directly demonstrated the cisternal progression of cargoes from the cis- to the trans-Golgi. Our data suggest that the constitutive efflux of secretory cargoes could be restricted at the Golgi stack, and the entry of the trans-Golgi network in secretory pathway could be signal dependent.
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Affiliation(s)
- Hieng Chiong Tie
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Divyanshu Mahajan
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Bing Chen
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Li Cheng
- Bioinformatics Institute, Singapore 138671 School of Computing, National University of Singapore, Singapore 117417
| | - Antonius M J VanDongen
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore 169857
| | - Lei Lu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
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35
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Abstract
The study of polarized protein trafficking in live neurons is critical for understanding neuronal structure and function. Given the complex anatomy of neurons and the numerous trafficking pathways that are active in them, however, visualization of specific vesicle populations leaving the Golgi complex presents unique challenges. Indeed, several approaches used in non-polarized cells, and even in polarized epithelial cells, have been less successful in neurons. Here, we describe an adaptation of the recently developed Retention Using Selective Hooks (RUSH) system (Boncompain et al., Nat Methods 9:493-498, 2012), previously used in non-polarized cells, to analyze the polarized sorting of proteins from the Golgi complex to dendrites and axons in live neurons. The RUSH system involves the retention of a fluorescently tagged cargo protein fused to the streptavidin-binding peptide (SBP) in the endoplasmic reticulum (ER) through the expression of an ER-hook protein fused to streptavidin. Upon D-biotin addition, the cargo protein is released and its traffic to dendrites and axons can be analyzed in live neurons.
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Oe S, Miki H, Nishimura W, Noda Y. Mechanism of the Dendritic Translation and Localization of Brain-derived Neurotrophic Factor. Cell Struct Funct 2016; 41:23-31. [DOI: 10.1247/csf.15015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Souichi Oe
- Division of Anatomy, Bio-imaging and Neuro-cell Science, Jichi Medical University
| | - Harukata Miki
- Division of Anatomy, Bio-imaging and Neuro-cell Science, Jichi Medical University
| | - Wataru Nishimura
- Division of Anatomy, Bio-imaging and Neuro-cell Science, Jichi Medical University
| | - Yasuko Noda
- Division of Anatomy, Bio-imaging and Neuro-cell Science, Jichi Medical University
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Ghanem E, Al-Balushi M. Adopting the rapamycin trapping assay to track the trafficking of murine MHC class I alleles, H-2K(b). BMC Cell Biol 2015; 16:30. [PMID: 26714929 PMCID: PMC4696223 DOI: 10.1186/s12860-015-0077-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 12/14/2015] [Indexed: 11/22/2022] Open
Abstract
Background In mammalian cells, the quality control (QC) of properly folded proteins is monitored in the early secretory pathway, particularly in the endoplasmic reticulum (ER). Several proteins, including our protein of interest, major histocompatibility complex class I (MHC class I), can bypass the first line of ER-QC and reside in post-ER compartments in an unfolded form. Such forms entail both monomeric and dimeric structures that are devoid of peptides and thus cannot fulfill the immunological function of antigen presentation at the cell surface. MHC class I structures become mature and properly folded once loaded with the appropriate peptides in the framework of the peptide loading complex (PLC). Despite the flood of information on the diverse trafficking behavior of different MHC class I alleles, there is still controversy on the actual trajectory followed by improperly folded murine MHC class I alleles, namely H-2Kb. In this study, we employ an in vitro rapamycin trapping assay, live cell imaging, and a biochemical COPII budding approach to further investigate the trafficking of H-2Kb beyond the level of the ER. Results We confirm the egress of H-2Kb in an unfolded form to a post-ER compartment from where they can cycle back to the ER. Deciphering the exact identity of the post-ER compartment by laser scanning microscopy did not only point to the existence of the ERGIC and cis-Golgi compartments as residency areas for unfolded proteins, but also to the involvement of an addional compartment, that lies in close proximity and possesses high resemblance to the aforementioned compartments. Interestingly, we were capable of showing using the same rapamycin trapping assay that H-2Kb can undergo a potential maturation event during their cycling; this is attained upon addition of peptides and trapping of accumulated post-ER molecules at the cell surface. Conclusions Our findings deepen the understanding of H-2Kb trafficking outside the ER and pave the way to decipher the role and the trafficking of certain PLC chaperones, such as tapasin, throughout H-2Kb post-ER QC. Finally, we demonstrate the plausible usage of the rapamycin assay to assess the trafficking of defected proteins especially in diseases and under therapeutic studies.
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Affiliation(s)
- Esther Ghanem
- Department of Biology, Faculty of Natural and Applied Sciences, Notre Dame University, 72, Zouk Mosbeh, Keserwan district, Lebanon.
| | - Mohammed Al-Balushi
- Department of Microbiology and Immunology, Sultan Qaboos University, Muscat, Oman.
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Cawley NX, Rathod T, Young S, Lou H, Birch N, Loh YP. Carboxypeptidase E and Secretogranin III Coordinately Facilitate Efficient Sorting of Proopiomelanocortin to the Regulated Secretory Pathway in AtT20 Cells. Mol Endocrinol 2015; 30:37-47. [PMID: 26646096 DOI: 10.1210/me.2015-1166] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Proopiomelanocortin (POMC) is a multivalent prohormone that can be processed into at least 7 biologically active peptide hormones. Processing can begin in the trans-Golgi network (TGN) and continues in the secretory granules of the regulated secretory pathway (RSP). Sorting of POMC into these granules is a complex process. Previously, a membrane-associated form of carboxypeptidase E (CPE) was shown to bind to POMC and facilitate its trafficking into these granules. More recently, secretogranin III (SgIII) was also found to affect POMC trafficking. Here, we show by RNA silencing that CPE and SgIII play a synergistic role in the trafficking of POMC to granules of the RSP in AtT20 cells. Reduction of either protein resulted in increased constitutive secretion of POMC and chromogranin A, which was increased even further when both proteins were reduced together, indicative of missorting at the TGN. In SgIII-reduced cells, POMC accumulated in a compartment that cofractionated and colocalized with syntaxin 6, a marker of the TGN, on sucrose density gradients and in immunocytochemistry, respectively, indicating an accumulation of this protein in the presumed sorting compartment. Regulated secretion of ACTH, as a measure of sorting and processing of POMC in mature granules, was reduced in the SgIII down-regulated cells but was increased in the CPE down-regulated cells. These results suggest that multiple sorting systems exist, providing redundancy to ensure the important task of continuous and accurate trafficking of prohormones to the granules of the RSP for the production of peptide hormones.
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Affiliation(s)
- Niamh X Cawley
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
| | - Trushar Rathod
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
| | - Sigrid Young
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
| | - Hong Lou
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
| | - Nigel Birch
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
| | - Y Peng Loh
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
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Arthur J, Huang J, Nomura N, Jin WW, Li W, Cheng X, Brown D, Lu HJ. Characterization of the putative phosphorylation sites of the AQP2 C terminus and their role in AQP2 trafficking in LLC-PK1 cells. Am J Physiol Renal Physiol 2015; 309:F673-9. [PMID: 26290367 PMCID: PMC4609919 DOI: 10.1152/ajprenal.00152.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 08/11/2015] [Indexed: 01/21/2023] Open
Abstract
Vasopressin (VP) stimulates a signaling cascade that results in phosphorylation and apical membrane accumulation of aquaporin-2 (AQP2), leading to water reabsorption by kidney collecting ducts. However, the roles of most C-terminal phosphorylation events in stimulated and constitutive AQP2 recycling are incompletely understood. Here, we generated LLC-PK1 cells containing point mutations of all potential phosphorylation sites in the AQP2 C terminus: S226, S229, T244, S256, S261, S264, and S269, to determine their impact on AQP2 trafficking. We produced an All Null AQP2 construct in which these serine (S) or threonine (T) residues were mutated to alanine (A) or glycine (G), and we then reintroduced the phosphorylation mimic aspartic acid (D) individually to each site in the All Null mutant. As expected, the All Null mutant does not accumulate at the plasma membrane in response to VP but still undergoes constitutive recycling, as shown by its membrane accumulation when endocytosis is blocked by methyl-β-cyclodextrin (MβCD), and accumulation in a perinuclear patch at low temperature (20°C). Single phosphorylation mimics S226D, S229D, T244D, S261D, S264D, and S269D were insufficient to cause membrane accumulation of AQP2 alone or after VP treatment. However, AQP2 S256 reintroduced into the All Null mutant maintains its trafficking response to VP. We conclude that 1) constitutive recycling of AQP2 does not require phosphorylation at any C-terminal sites; 2) forced "phosphorylation" of sites in the AQP2 C terminus is insufficient to stimulate membrane accumulation in the absence of S256 phosphorylation; and 3) phosphorylation of S256 alone is necessary and sufficient to cause membrane accumulation of AQP2.
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Affiliation(s)
- Julian Arthur
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Jianmin Huang
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Naohiro Nomura
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - William W. Jin
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Wei Li
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Xiang Cheng
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Hua Jenny Lu
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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40
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Briant K, Koay YH, Otsuka Y, Swanton E. ERAD of proteins containing aberrant transmembrane domains requires ubiquitylation of cytoplasmic lysine residues. J Cell Sci 2015; 128:4112-25. [PMID: 26446255 PMCID: PMC4712780 DOI: 10.1242/jcs.171215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 09/28/2015] [Indexed: 11/29/2022] Open
Abstract
Clearance of misfolded proteins from the endoplasmic reticulum (ER) is mediated by the ubiquitin-proteasome system in a process known as ER-associated degradation (ERAD). The mechanisms through which proteins containing aberrant transmembrane domains are degraded by ERAD are poorly understood. To address this question, we generated model ERAD substrates based on CD8 with either a non-native transmembrane domain but a folded ER luminal domain (CD8TMD*), or the native transmembrane domain but a misfolded luminal domain (CD8LUM*). Although both chimeras were degraded by ERAD, we found that the location of the folding defect determined the initial site of ubiquitylation. Ubiquitylation of cytoplasmic lysine residues was required for the extraction of CD8TMD* from the ER membrane during ERAD, whereas CD8LUM* continued to be degraded in the absence of cytoplasmic lysine residues. Cytoplasmic lysine residues were also required for degradation of an additional ERAD substrate containing an unassembled transmembrane domain and when a non-native transmembrane domain was introduced into CD8LUM*. Our results suggest that proteins with defective transmembrane domains are removed from the ER through a specific ERAD mechanism that depends upon ubiquitylation of cytoplasmic lysine residues. Summary: Proteins containing defective transmembrane domains are removed from the endoplasmic reticulum through a specific mechanism that depends upon the ubiquitylation of cytoplasmic lysine residues.
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Affiliation(s)
- Kit Briant
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Yee-Hui Koay
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Yuka Otsuka
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Eileithyia Swanton
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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41
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Farr GA, Hull M, Stoops EH, Bateson R, Caplan MJ. Dual pulse-chase microscopy reveals early divergence in the biosynthetic trafficking of the Na,K-ATPase and E-cadherin. Mol Biol Cell 2015; 26:4401-11. [PMID: 26424804 PMCID: PMC4666135 DOI: 10.1091/mbc.e14-09-1385] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 09/24/2015] [Indexed: 11/14/2022] Open
Abstract
The trafficking of newly synthesized Na,K-ATPase and E-cadherin is observed in polarized epithelial cells. E-cadherin’s exit from the Golgi complex is not susceptible to 19°C temperature block. Furthermore, these proteins exit the Golgi and are delivered to the basolateral cell surface in separate vascular carriers. Recent evidence indicates that newly synthesized membrane proteins that share the same distributions in the plasma membranes of polarized epithelial cells can pursue a variety of distinct trafficking routes as they travel from the Golgi complex to their common destination at the cell surface. In most polarized epithelial cells, both the Na,K-ATPase and E-cadherin are localized to the basolateral domains of the plasma membrane. To examine the itineraries pursued by newly synthesized Na,K-ATPase and E-cadherin in polarized MDCK epithelial cells, we used the SNAP and CLIP labeling systems to fluorescently tag temporally defined cohorts of these proteins and observe their behaviors simultaneously as they traverse the secretory pathway. These experiments reveal that E-cadherin is delivered to the cell surface substantially faster than is the Na,K-ATPase. Furthermore, the surface delivery of newly synthesized E-cadherin to the plasma membrane was not prevented by the 19°C temperature block that inhibits the trafficking of most proteins, including the Na,K-ATPase, out of the trans-Golgi network. Consistent with these distinct behaviors, populations of newly synthesized E-cadherin and Na,K-ATPase become separated from one another within the trans-Golgi network, suggesting that they are sorted into different carrier vesicles that mediate their post-Golgi trafficking.
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Affiliation(s)
- Glen A Farr
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520-8026
| | - Michael Hull
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520-8026
| | - Emily H Stoops
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520-8026
| | - Rosalie Bateson
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520-8026
| | - Michael J Caplan
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520-8026 )
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Mihov D, Raja E, Spiess M. Chondroitin Sulfate Accelerates Trans-Golgi-to-Surface Transport of Proteoglycan Amyloid Precursor Protein. Traffic 2015; 16:853-70. [PMID: 25951880 DOI: 10.1111/tra.12294] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 04/15/2015] [Accepted: 04/15/2015] [Indexed: 11/28/2022]
Abstract
The amyloid precursor protein (APP) is a membrane protein implicated in the pathogenesis of Alzheimer's disease. APP is a part-time proteoglycan, as splice variants lacking exon 15 are modified by a chondroitin sulfate glycosaminoglycan (GAG) chain. Investigating the effect of the GAG chain on the trafficking of APP in non-polarized cells, we found it to increase the steady-state surface-to-intracellular distribution, to reduce the rate of endocytosis and to accelerate transport kinetics from the trans-Golgi network (TGN) to the plasma membrane. Deletion of the cytosolic domain resulted in delayed surface arrival of GAG-free APP, but did not affect the rapid export kinetics of the proteoglycan form. Protein-free GAG chains showed the same TGN-to-cell surface transport kinetics as proteoglycan APP. Endosome ablation experiments were performed to distinguish between indirect endosomal and direct pathways to the cell surface. Surprisingly, TGN-to-cell surface transport of both GAG-free and proteoglycan APP was found to be indirect via transferrin-positive endosomes. Our results show that GAGs act as alternative sorting determinants in cellular APP transport that are dominant over cytoplasmic signals and involve distinct sorting mechanisms.
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Affiliation(s)
- Deyan Mihov
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland
| | - Eva Raja
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland
| | - Martin Spiess
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland
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Molino D, Nola S, Lam SM, Verraes A, Proux-Gillardeaux V, Boncompain G, Perez F, Wenk M, Shui G, Danglot L, Galli T. Role of tetanus neurotoxin insensitive vesicle-associated membrane protein in membrane domains transport and homeostasis. CELLULAR LOGISTICS 2015. [PMID: 26196023 PMCID: PMC4501207 DOI: 10.1080/21592799.2015.1025182] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Biological membranes in eukaryotes contain a large variety of proteins and lipids often distributed in domains in plasma membrane and endomembranes. Molecular mechanisms responsible for the transport and the organization of these membrane domains along the secretory pathway still remain elusive. Here we show that vesicular SNARE TI-VAMP/VAMP7 plays a major role in membrane domains composition and transport. We found that the transport of exogenous and endogenous GPI-anchored proteins was altered in fibroblasts isolated from VAMP7-knockout mice. Furthermore, disassembly and reformation of the Golgi apparatus induced by Brefeldin A treatment and washout were impaired in VAMP7-depleted cells, suggesting that loss of VAMP7 expression alters biochemical properties and dynamics of the Golgi apparatus. In addition, lipid profiles from these knockout cells indicated a defect in glycosphingolipids homeostasis. We conclude that VAMP7 is required for effective transport of GPI–anchored proteins to cell surface and that VAMP7-dependent transport contributes to both sphingolipids and Golgi homeostasis.
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Key Words
- BFA, Brefeldin A
- Cer, Ceramide
- ER, Endoplasmic Reticulum
- GM3, ganglioside monosialic acid 3
- GPI, Glycosylphosphatidylinositol
- GSL, Glycosphingolipids
- GlcCer, Glucosylceramide
- Golgi apparatus
- LC, Long Chain
- PI, Phosphatidylinositide
- PM, Plasma Membrane
- SM, Sphingomyelin
- SNARE
- TGN, = Trans-Golgi Network
- TI-VAMP/VAMP7
- TI-VAMP/VAMP7, Tetanus neurotoxin-insensitive vesicle-associated membrane protein / Vesicle associated membrane protein 7
- VLC, very long vhain
- VSVG, Vesicular Stomatitis Virus Glycoprotein
- exocytosis
- sphingolipids
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Affiliation(s)
- Diana Molino
- INSERM; U950; Membrane Traffic in Health and Disease ; Paris, France ; Univ Paris Diderot ; Sorbonne Paris Cité; ERL U950 ; Paris, France ; CNRS; UMR 7592; Institut Jacques Monod ; Paris, France ; Ecole Normale Supérieure-PSL Research University; Département de Chimie; Sorbonne Universités - UPMC Univ Paris 06 ; CNRS UMR 8640 PASTEUR ; Paris, France
| | - Sébastien Nola
- INSERM; U950; Membrane Traffic in Health and Disease ; Paris, France ; Univ Paris Diderot ; Sorbonne Paris Cité; ERL U950 ; Paris, France ; CNRS; UMR 7592; Institut Jacques Monod ; Paris, France
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology; Institute of Genetics and Developmental Biology; Chinese Academy of Sciences ; Beijing, China
| | - Agathe Verraes
- INSERM; U950; Membrane Traffic in Health and Disease ; Paris, France ; Univ Paris Diderot ; Sorbonne Paris Cité; ERL U950 ; Paris, France ; CNRS; UMR 7592; Institut Jacques Monod ; Paris, France
| | - Véronique Proux-Gillardeaux
- INSERM; U950; Membrane Traffic in Health and Disease ; Paris, France ; Univ Paris Diderot ; Sorbonne Paris Cité; ERL U950 ; Paris, France ; CNRS; UMR 7592; Institut Jacques Monod ; Paris, France
| | | | | | - Markus Wenk
- Department of Biochemistry; National University of Singapore; Yong Loo Lin School of Medicine ; Singapore
| | - Guanghou Shui
- State Key Laboratory of Molecular Developmental Biology; Institute of Genetics and Developmental Biology; Chinese Academy of Sciences ; Beijing, China
| | - Lydia Danglot
- INSERM; U950; Membrane Traffic in Health and Disease ; Paris, France ; Univ Paris Diderot ; Sorbonne Paris Cité; ERL U950 ; Paris, France ; CNRS; UMR 7592; Institut Jacques Monod ; Paris, France
| | - Thierry Galli
- INSERM; U950; Membrane Traffic in Health and Disease ; Paris, France ; Univ Paris Diderot ; Sorbonne Paris Cité; ERL U950 ; Paris, France ; CNRS; UMR 7592; Institut Jacques Monod ; Paris, France
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El Najjar F, Lampe L, Baker ML, Wang LF, Dutch RE. Analysis of cathepsin and furin proteolytic enzymes involved in viral fusion protein activation in cells of the bat reservoir host. PLoS One 2015; 10:e0115736. [PMID: 25706132 PMCID: PMC4338073 DOI: 10.1371/journal.pone.0115736] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 11/18/2014] [Indexed: 12/12/2022] Open
Abstract
Bats of different species play a major role in the emergence and transmission of highly pathogenic viruses including Ebola virus, SARS-like coronavirus and the henipaviruses. These viruses require proteolytic activation of surface envelope glycoproteins needed for entry, and cellular cathepsins have been shown to be involved in proteolysis of glycoproteins from these distinct virus families. Very little is currently known about the available proteases in bats. To determine whether the utilization of cathepsins by bat-borne viruses is related to the nature of proteases in their natural hosts, we examined proteolytic processing of several viral fusion proteins in cells derived from two fruit bat species, Pteropus alecto and Rousettus aegyptiacus. Our work shows that fruit bat cells have homologs of cathepsin and furin proteases capable of cleaving and activating both the cathepsin-dependent Hendra virus F and the furin-dependent parainfluenza virus 5 F proteins. Sequence analysis comparing Pteropus alecto furin and cathepsin L to proteases from other mammalian species showed a high degree of conservation; however significant amino acid variation occurs at the C-terminus of Pteropus alecto furin. Further analysis of furin-like proteases from fruit bats revealed that these proteases are catalytically active and resemble other mammalian furins in their response to a potent furin inhibitor. However, kinetic analysis suggests that differences may exist in the cellular localization of furin between different species. Collectively, these results indicate that the unusual role of cathepsin proteases in the life cycle of bat-borne viruses is not due to the lack of active furin-like proteases in these natural reservoir species; however, differences may exist between furin proteases present in fruit bats compared to furins in other mammalian species, and these differences may impact protease usage for viral glycoprotein processing.
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Affiliation(s)
- Farah El Najjar
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Levi Lampe
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Michelle L. Baker
- CSIRO Australian Animal Health Laboratory, East Geelong, Victoria, Australia
| | - Lin-Fa Wang
- CSIRO Australian Animal Health Laboratory, East Geelong, Victoria, Australia
- Program in Emerging Infectious Diseases, Duke–National University of Singapore Graduate Medical School, Singapore, Singapore
| | - Rebecca Ellis Dutch
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
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Lehmann GL, Benedicto I, Philp NJ, Rodriguez-Boulan E. Plasma membrane protein polarity and trafficking in RPE cells: past, present and future. Exp Eye Res 2014; 126:5-15. [PMID: 25152359 DOI: 10.1016/j.exer.2014.04.021] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 04/15/2014] [Accepted: 04/24/2014] [Indexed: 10/24/2022]
Abstract
The retinal pigment epithelium (RPE) comprises a monolayer of polarized pigmented epithelial cells that is strategically interposed between the neural retina and the fenestrated choroid capillaries. The RPE performs a variety of vectorial transport functions (water, ions, metabolites, nutrients and waste products) that regulate the composition of the subretinal space and support the functions of photoreceptors (PRs) and other cells in the neural retina. To this end, RPE cells display a polarized distribution of channels, transporters and receptors in their plasma membrane (PM) that is remarkably different from that found in conventional extra-ocular epithelia, e.g. intestine, kidney, and gall bladder. This characteristic PM protein polarity of RPE cells depends on the interplay of sorting signals in the RPE PM proteins and sorting mechanisms and biosynthetic/recycling trafficking routes in the RPE cell. Although considerable progress has been made in our understanding of the RPE trafficking machinery, most available data have been obtained from immortalized RPE cell lines that only partially maintain the RPE phenotype and by extrapolation of data obtained in the prototype Madin-Darby Canine Kidney (MDCK) cell line. The increasing availability of RPE cell cultures that more closely resemble the RPE in vivo together with the advent of advanced live imaging microscopy techniques provides a platform and an opportunity to rapidly expand our understanding of how polarized protein trafficking contributes to RPE PM polarity.
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Affiliation(s)
- Guillermo L Lehmann
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, 1300 York Ave, New York, NY 100652, USA
| | - Ignacio Benedicto
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, 1300 York Ave, New York, NY 100652, USA
| | - Nancy J Philp
- Thomas Jefferson University, Department of Pathology, Anatomy, and Cell Biology, Philadelphia, PA 19107, USA.
| | - Enrique Rodriguez-Boulan
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, 1300 York Ave, New York, NY 100652, USA.
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Baschieri F, Confalonieri S, Bertalot G, Di Fiore PP, Dietmaier W, Leist M, Crespo P, Macara IG, Farhan H. Spatial control of Cdc42 signalling by a GM130-RasGRF complex regulates polarity and tumorigenesis. Nat Commun 2014; 5:4839. [PMID: 25208761 DOI: 10.1038/ncomms5839] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 07/29/2014] [Indexed: 12/27/2022] Open
Abstract
The small GTPase Cdc42 is a key regulator of polarity, but little is known in mammals about its spatial regulation and the relevance of spatial Cdc42 pools for polarity. Here we report the identification of a GM130-RasGRF complex as a regulator of Cdc42 at the Golgi. Silencing GM130 results in RasGRF-dependent inhibition of the Golgi pool of Cdc42, but does not affect Cdc42 at the cell surface. Furthermore, active Cdc42 at the Golgi is important to sustain asymmetric front-rear Cdc42-GTP distribution in directionally migrating cells. Concurrent to Cdc42 inhibition, silencing GM130 also results in RasGRF-dependent Ras-ERK pathway activation. Moreover, depletion of GM130 is sufficient to induce E-cadherin downregulation, indicative of a loss in cell polarity and epithelial identity. Accordingly, GM130 expression is frequently lost in colorectal and breast cancer patients. These findings establish a previously unrecognized role for a GM130-RasGRF-Cdc42 connection in regulating polarity and tumorigenesis.
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Affiliation(s)
- Francesco Baschieri
- 1] University of Konstanz, 78464 Konstanz, Germany [2] Biotechnology Institute Thurgau, University of Konstanz, Kreuzlingen CH-8280, Switzerland
| | - Stefano Confalonieri
- 1] Molecular Medicine for Care Program, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy [2] IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Giovanni Bertalot
- Molecular Medicine for Care Program, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy
| | - Pier Paolo Di Fiore
- 1] Molecular Medicine for Care Program, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy [2] IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy [3] Dipartimento di Scienze della Salute, Università degli Studi di Milano, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Wolfgang Dietmaier
- University of Regensburg, Institute of Pathology and molecular diagnostics, 93053 Regensbur, Germany
| | | | - Piero Crespo
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Cantabria-SODERCAN. 39005 Santander, Spain
| | - Ian G Macara
- Department of Cell &Developmental Biology, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - Hesso Farhan
- 1] University of Konstanz, 78464 Konstanz, Germany [2] Biotechnology Institute Thurgau, University of Konstanz, Kreuzlingen CH-8280, Switzerland
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47
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Jensen CS, Misonou H. Live-cell imaging of post-golgi transport vesicles in cultured hippocampal neurons. Cell Mol Neurobiol 2014; 35:123-35. [PMID: 25182224 DOI: 10.1007/s10571-014-0103-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 08/23/2014] [Indexed: 11/26/2022]
Abstract
The subcellular localization of neuronal membrane signaling molecules such as receptors and ion channels depends on intracellular trafficking mechanisms. Essentially, vesicular trafficking mechanisms ensure that a large number of membrane proteins are correctly targeted to different subcellular compartments of neurons. In the past two decades, the establishment and advancement of fluorescent protein technology have provided us with opportunities to study how proteins are trafficked in living cells. However, live imaging of trafficking processes in neurons necessitate imaging tools to distinguish the several different routes that neurons use for protein trafficking. Here we provide a novel protocol to selectively visualize post-Golgi transport vesicles carrying fluorescent-labeled ion channel proteins in living neurons. Further, we provide a number of analytical tools we developed to quantify characteristics of different types of transport vesicles. We demonstrate the application of our protocol to investigate whether ion channels are sorted into distinct vesicular populations at the Golgi apparatus. We also demonstrate how these techniques are suitable for pharmacological dissection of the transport mechanisms by which post-Golgi vesicles are trafficked in neurons. Our protocol uniquely combines the classic temperature-block with close monitoring of the transient expression of transfected protein tagged with fluorescent proteins, and provides a quick and easy way to study protein trafficking in living neurons. We believe that the procedures described here are useful for researchers who are interested in studying molecular mechanisms of protein trafficking in neurons.
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Affiliation(s)
- Camilla Stampe Jensen
- Department of Neural and Pain Sciences, University of Maryland, Baltimore, MD, 21201, USA
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48
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Fossati M, Colombo SF, Borgese N. A positive signal prevents secretory membrane cargo from recycling between the Golgi and the ER. EMBO J 2014; 33:2080-97. [PMID: 25063674 DOI: 10.15252/embj.201488367] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The Golgi complex and ER are dynamically connected by anterograde and retrograde trafficking pathways. To what extent and by what mechanism outward-bound cargo proteins escape retrograde trafficking has been poorly investigated. Here, we analysed the behaviour of several membrane proteins at the ER/Golgi interface in live cells. When Golgi-to-plasma membrane transport was blocked, vesicular stomatitis virus glycoprotein (VSVG), which bears an ER export signal, accumulated in the Golgi, whereas an export signal-deleted version of VSVG attained a steady state determined by the balance of retrograde and anterograde traffic. A similar behaviour was displayed by EGF receptor and by a model tail-anchored protein, whose retrograde traffic was slowed by addition of VSVG's export signal. Retrograde trafficking was energy- and Rab6-dependent, and Rab6 inhibition accelerated signal-deleted VSVG's transport to the cell surface. Our results extend the dynamic bi-directional relationship between the Golgi and ER to include surface-directed proteins, uncover an unanticipated role for export signals at the Golgi complex, and identify recycling as a novel factor that regulates cargo transport out of the early secretory pathway.
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Affiliation(s)
- Matteo Fossati
- BIOMETRA Department, CNR Institute of Neuroscience, Università degli Studi di Milano, Milano, Italy
| | - Sara F Colombo
- BIOMETRA Department, CNR Institute of Neuroscience, Università degli Studi di Milano, Milano, Italy
| | - Nica Borgese
- BIOMETRA Department, CNR Institute of Neuroscience, Università degli Studi di Milano, Milano, Italy Department of Health Science, Magna Graecia University of Catanzaro, Catanzaro, Italy
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49
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Abstract
Protein trafficking within the secretory pathway of mammalian cells is amenable to analysis by biochemical methods. This can be achieved by monitoring posttranslational modifications that occur naturally within the secretory pathway, or by measuring the delivery of cargo to the cell surface or extracellular medium. These approaches can be combined with additional manipulations such as specific temperature blocks that permit analysis of distinct trafficking steps. Biochemical analysis is advantageous in that it permits both a sensitive and quantitative measure of trafficking along the pathway. The methods discussed in this chapter permit the analysis of trafficking of both endogenous cargo proteins and ectopically expressed model cargos, which can be followed using either Western blotting or metabolic pulse-chase approaches. These methods are relatively straightforward and suitable for use in most modern cell biology laboratories. In addition to the well-established methods that we describe here in detail, we also refer to the development of more recent tailored approaches that add further to the arsenal of tools that can be used to assess trafficking in the secretory pathway.
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Affiliation(s)
- Peristera Roboti
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
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50
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Hanus C, Kochen L, Tom Dieck S, Racine V, Sibarita JB, Schuman EM, Ehlers MD. Synaptic control of secretory trafficking in dendrites. Cell Rep 2014; 7:1771-8. [PMID: 24931613 PMCID: PMC5321479 DOI: 10.1016/j.celrep.2014.05.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 03/16/2014] [Accepted: 05/14/2014] [Indexed: 11/24/2022] Open
Abstract
Localized signaling in neuronal dendrites requires tight spatial control of membrane composition. Upon initial synthesis, nascent secretory cargo in dendrites exits the endoplasmic reticulum (ER) from local zones of ER complexity that are spatially coupled to post-ER compartments. Although newly synthesized membrane proteins can be processed locally, the mechanisms that control the spatial range of secretory cargo transport in dendritic segments are unknown. Here, we monitored the dynamics of nascent membrane proteins in dendritic post-ER compartments under regimes of low or increased neuronal activity. In response to activity blockade, post-ER carriers are highly mobile and are transported over long distances. Conversely, increasing synaptic activity dramatically restricts the spatial scale of post-ER trafficking along dendrites. This activity-induced confinement of secretory cargo requires site-specific phosphorylation of the kinesin motor KIF17 by Ca2+/calmodulin-dependent protein kinases (CaMK). Thus, the length scales of early secretory trafficking in dendrites are tuned by activity-dependent regulation of microtubule-dependent transport.
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Affiliation(s)
- Cyril Hanus
- Max Planck Institute for Brain Research, Frankfurt 60438, Germany.
| | - Lisa Kochen
- Max Planck Institute for Brain Research, Frankfurt 60438, Germany
| | | | - Victor Racine
- Institute of Molecular & Cell Biology, Agency for Science, Technology and Research, Singapore 138673, Singapore
| | | | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt 60438, Germany
| | - Michael D Ehlers
- Neuroscience Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA 02139, USA.
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