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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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52
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Zurzolo C, Simons K. Glycosylphosphatidylinositol-anchored proteins: Membrane organization and transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:632-9. [DOI: 10.1016/j.bbamem.2015.12.018] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 12/12/2015] [Accepted: 12/15/2015] [Indexed: 11/17/2022]
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53
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Pu J, Cao L, McCaig CD. Physiological extracellular electrical signals guide and orient the polarity of gut epithelial cells. Tissue Barriers 2015; 3:e1037417. [PMID: 26451341 PMCID: PMC4574889 DOI: 10.1080/21688370.2015.1037417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/24/2015] [Accepted: 03/27/2015] [Indexed: 01/09/2023] Open
Abstract
Apical-basal polarity in epithelial cells is a fundamental process in the morphogenesis of many tissues. But how epithelial cells become oriented with functionally specialized luminal and serosal facing membranes is not understood fully. Cell-cell and cell-substrate contacts induce the asymmetric distribution of Na+/K+-ATPase pumps on basal membrane and are essential for apical-basal polarity formation. Inhibition of the Na+/K+-ATPase pump abolished apical formation completely. But it is unclear how this pump regulated the apical polarity. We discovered that the transepithelial potential difference (TEP) which is dependent on the basal Na+/K+-ATPase distribution acts as an essential coordinating signal for apical membrane formation through Ror2/ERK1/2/LKB1 signaling. A similar concept applies to all other ion-transporting epithelial and endothelial tissues and this raises the possibility of regulating the TEP as a therapeutic intervention for disorders in which epithelial function is compromised by faulty electrical signaling.
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Affiliation(s)
- Jin Pu
- School of Medical Sciences; Institute of Medical Sciences; University of Aberdeen ; Aberdeen, UK
| | - Lin Cao
- School of Medical Sciences; Institute of Medical Sciences; University of Aberdeen ; Aberdeen, UK
| | - Colin D McCaig
- School of Medical Sciences; Institute of Medical Sciences; University of Aberdeen ; Aberdeen, UK
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54
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Muñiz M, Riezman H. Trafficking of glycosylphosphatidylinositol anchored proteins from the endoplasmic reticulum to the cell surface. J Lipid Res 2015; 57:352-60. [PMID: 26450970 DOI: 10.1194/jlr.r062760] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Indexed: 11/20/2022] Open
Abstract
In eukaryotes, many cell surface proteins are attached to the plasma membrane via a glycolipid glycosylphosphatidylinositol (GPI) anchor. GPI-anchored proteins (GPI-APs) receive the GPI anchor as a conserved posttranslational modification in the lumen of the endoplasmic reticulum (ER). After anchor attachment, the GPI anchor is structurally remodeled to function as a transport signal that actively triggers the delivery of GPI-APs from the ER to the plasma membrane, via the Golgi apparatus. The structure and composition of the GPI anchor confer a special mode of interaction with membranes of GPI-APs within the lumen of secretory organelles that lead them to be differentially trafficked from other secretory membrane proteins. In this review, we examine the mechanisms by which GPI-APs are selectively transported through the secretory pathway, with special focus on the recent progress made in their actively regulated export from the ER and the trans-Golgi network.
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Affiliation(s)
- Manuel Muñiz
- Departamento de Biología Celular, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Howard Riezman
- National Centre of Competence in Research (NCCR) Chemical Biology, Department of Biochemistry, University of Geneva, Geneva, Switzerland
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55
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Butler B, Saha K, Rana T, Becker JP, Sambo D, Davari P, Goodwin JS, Khoshbouei H. Dopamine Transporter Activity Is Modulated by α-Synuclein. J Biol Chem 2015; 290:29542-54. [PMID: 26442590 DOI: 10.1074/jbc.m115.691592] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Indexed: 12/24/2022] Open
Abstract
The duration and strength of the dopaminergic signal are regulated by the dopamine transporter (DAT). Drug addiction and neurodegenerative and neuropsychiatric diseases have all been associated with altered DAT activity. The membrane localization and the activity of DAT are regulated by a number of intracellular proteins. α-Synuclein, a protein partner of DAT, is implicated in neurodegenerative disease and drug addiction. Little is known about the regulatory mechanisms of the interaction between DAT and α-synuclein, the cellular location of this interaction, and the functional consequences of this interaction on the basal, amphetamine-induced DAT-mediated dopamine efflux, and membrane microdomain distribution of the transporter. Here, we found that the majority of DAT·α-synuclein protein complexes are found at the plasma membrane of dopaminergic neurons or mammalian cells and that the amphetamine-mediated increase in DAT activity enhances the association of these proteins at the plasma membrane. Further examination of the interaction of DAT and α-synuclein revealed a transient interaction between these two proteins at the plasma membrane. Additionally, we found DAT-induced membrane depolarization enhances plasma membrane localization of α-synuclein, which in turn increases dopamine efflux and enhances DAT localization in cholesterol-rich membrane microdomains.
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Affiliation(s)
- Brittany Butler
- From the Departments of Neuroscience and Psychiatry University of Florida, Gainesville, Florida 32611 and
| | - Kaustuv Saha
- From the Departments of Neuroscience and Psychiatry University of Florida, Gainesville, Florida 32611 and
| | - Tanu Rana
- the Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, Tennessee 37208
| | - Jonas P Becker
- From the Departments of Neuroscience and Psychiatry University of Florida, Gainesville, Florida 32611 and
| | - Danielle Sambo
- From the Departments of Neuroscience and Psychiatry University of Florida, Gainesville, Florida 32611 and
| | - Paran Davari
- From the Departments of Neuroscience and Psychiatry University of Florida, Gainesville, Florida 32611 and
| | - J Shawn Goodwin
- the Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, Tennessee 37208
| | - Habibeh Khoshbouei
- From the Departments of Neuroscience and Psychiatry University of Florida, Gainesville, Florida 32611 and
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56
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Singh DR, Cao Q, King C, Salotto M, Ahmed F, Zhou XY, Pasquale EB, Hristova K. Unliganded EphA3 dimerization promoted by the SAM domain. Biochem J 2015; 471:101-9. [PMID: 26232493 PMCID: PMC4692061 DOI: 10.1042/bj20150433] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 07/28/2015] [Accepted: 07/31/2015] [Indexed: 01/03/2023]
Abstract
The erythropoietin-producing hepatocellular carcinoma A3 (EphA3) receptor tyrosine kinase (RTK) regulates morphogenesis during development and is overexpressed and mutated in a variety of cancers. EphA3 activation is believed to follow a 'seeding mechanism' model, in which ligand binding to the monomeric receptor acts as a trigger for signal-productive receptor clustering. We study EphA3 lateral interactions on the surface of live cells and we demonstrate that EphA3 forms dimers in the absence of ligand binding. We further show that these dimers are stabilized by interactions involving the EphA3 sterile α-motif (SAM) domain. The discovery of unliganded EphA3 dimers challenges the current understanding of the chain of EphA3 activation events and suggests that EphA3 may follow the 'pre-formed dimer' model of activation known to be relevant for other receptor tyrosine kinases. The present work also establishes a new role for the SAM domain in promoting Eph receptor lateral interactions and signalling on the cell surface.
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Affiliation(s)
- Deo R Singh
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21212, U.S.A
| | - QingQing Cao
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21212, U.S.A
| | - Christopher King
- Program in Molecular Biophysics, Johns Hopkins University, Baltimore, MD 21212, U.S.A
| | - Matt Salotto
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21212, U.S.A
| | - Fozia Ahmed
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21212, U.S.A
| | - Xiang Yang Zhou
- Vaccine Center, The Wistar Institute, Philadelphia, PA 19104, U.S.A
| | - Elena B Pasquale
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, U.S.A
| | - Kalina Hristova
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21212, U.S.A. Program in Molecular Biophysics, Johns Hopkins University, Baltimore, MD 21212, U.S.A.
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57
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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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58
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Scolari S, Imkeller K, Jolmes F, Veit M, Herrmann A, Schwarzer R. Modulation of cell surface transport and lipid raft localization by the cytoplasmic tail of the influenza virus hemagglutinin. Cell Microbiol 2015; 18:125-36. [PMID: 26243691 PMCID: PMC7162421 DOI: 10.1111/cmi.12491] [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: 03/27/2015] [Revised: 06/28/2015] [Accepted: 07/13/2015] [Indexed: 11/30/2022]
Abstract
Viral glycoproteins are highly variable in their primary structure, but on the other hand feature a high functional conservation to fulfil their versatile tasks during the pathogenic life cycle. Typically, all protein domains are optimized in that indispensable functions can be assigned to small conserved motifs or even individual amino acids. The cytoplasmic tail of many viral spike proteins, although of particular relevance for the virus biology, is often only insufficiently characterized. Hemagglutinin (HA), the receptor-binding protein of the influenza virus comprises a short cytoplasmic tail of 13 amino acids that exhibits three highly conserved palmitoylation sites. However, the particular importance of these modifications and the tail in general for intracellular trafficking and lateral membrane organization remains elusive. In this study, we generated HA core proteins consisting of transmembrane domain, cytoplasmic tail and a minor part of the ectodomain, tagged with a yellow fluorescent protein. Different mutation and truncation variants of these chimeric proteins were investigated using confocal microscopy, to characterize the role of cytoplasmic tail and palmitoylation for the intracellular trafficking to plasma membrane and Golgi apparatus. In addition, we assessed raft partitioning of the variants by Foerster resonance energy transfer with an established raft marker. We revealed a substantial influence of the cytoplasmic tail length on the intracellular distribution and surface exposure of the proteins. A complete removal of the tail hampers a physiological trafficking of the protein, whereas a partial truncation can be compensated by cytoplasmic palmitoylations. Plasma membrane raft partitioning on the other hand was found to imperatively require palmitoylations, and the cysteine at position 551 turned out to be of most relevance. Our data shed further light on the tight interconnection between cytoplasmic elements and intracellular trafficking and suggest a function of HA palmitoylations in both lateral sorting and anterograde trafficking of the glycoprotein.
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Affiliation(s)
- Silvia Scolari
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Katharina Imkeller
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Fabian Jolmes
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Michael Veit
- Department of Immunology and Molecular Biology, Free University, 14163, Berlin, Germany
| | - Andreas Herrmann
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Roland Schwarzer
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany.,Department of Biological Chemistry, Weizmann Institute of Science, 76100, Rehovot, Israel
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59
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Novel microscopy-based screening method reveals regulators of contact-dependent intercellular transfer. Sci Rep 2015; 5:12879. [PMID: 26271723 PMCID: PMC4536488 DOI: 10.1038/srep12879] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 07/10/2015] [Indexed: 12/23/2022] Open
Abstract
Contact-dependent intercellular transfer (codeIT) of cellular constituents can have functional consequences for recipient cells, such as enhanced survival and drug resistance. Pathogenic viruses, prions and bacteria can also utilize this mechanism to spread to adjacent cells and potentially evade immune detection. However, little is known about the molecular mechanism underlying this intercellular transfer process. Here, we present a novel microscopy-based screening method to identify regulators and cargo of codeIT. Single donor cells, carrying fluorescently labelled endocytic organelles or proteins, are co-cultured with excess acceptor cells. CodeIT is quantified by confocal microscopy and image analysis in 3D, preserving spatial information. An siRNA-based screening using this method revealed the involvement of several myosins and small GTPases as codeIT regulators. Our data indicates that cellular protrusions and tubular recycling endosomes are important for codeIT. We automated image acquisition and analysis to facilitate large-scale chemical and genetic screening efforts to identify key regulators of codeIT.
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60
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Sendra GH, Hoerth CH, Wunder C, Lorenz H. 2D map projections for visualization and quantitative analysis of 3D fluorescence micrographs. Sci Rep 2015. [PMID: 26208256 PMCID: PMC4513544 DOI: 10.1038/srep12457] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We introduce Map3-2D, a freely available software to accurately project up to five-dimensional (5D) fluorescence microscopy image data onto full-content 2D maps. Similar to the Earth’s projection onto cartographic maps, Map3-2D unfolds surface information from a stack of images onto a single, structurally connected map. We demonstrate its applicability for visualization and quantitative analyses of spherical and uneven surfaces in fixed and dynamic live samples by using mammalian and yeast cells, and giant unilamellar vesicles. Map3-2D software is available at http://www.zmbh.uni-heidelberg.de//Central_Services/Imaging_Facility/Map3-2D.html.
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Affiliation(s)
- G Hernán Sendra
- Center of Molecular Biology, University of Heidelberg (ZMBH), Heidelberg, Germany
| | - Christian H Hoerth
- Center of Molecular Biology, University of Heidelberg (ZMBH), Heidelberg, Germany
| | - Christian Wunder
- 1] Institut Curie -Centre de Recherche, Endocytic Trafficking and Therapeutic Delivery group, Paris, France [2] CNRS UMR3666, INSERM U1143, France
| | - Holger Lorenz
- Center of Molecular Biology, University of Heidelberg (ZMBH), Heidelberg, Germany
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61
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Oxygen depletion speeds and simplifies diffusion in HeLa cells. Biophys J 2015; 107:1873-1884. [PMID: 25418168 DOI: 10.1016/j.bpj.2014.08.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 12/28/2022] Open
Abstract
Many cell types undergo a hypoxic response in the presence of low oxygen, which can lead to transcriptional, metabolic, and structural changes within the cell. Many biophysical studies to probe the localization and dynamics of single fluorescently labeled molecules in live cells either require or benefit from low-oxygen conditions. In this study, we examine how low-oxygen conditions alter the mobility of a series of plasma membrane proteins with a range of anchoring motifs in HeLa cells at 37°C. Under high-oxygen conditions, diffusion of all proteins is heterogeneous and confined. When oxygen is reduced with an enzymatic oxygen-scavenging system for ≥ 15 min, diffusion rates increase by > 2-fold, motion becomes unconfined on the timescales and distance scales investigated, and distributions of diffusion coefficients are remarkably consistent with those expected from Brownian motion. More subtle changes in protein mobility are observed in several other laboratory cell lines examined under both high- and low-oxygen conditions. Morphological changes and actin remodeling are observed in HeLa cells placed in a low-oxygen environment for 30 min, but changes are less apparent in the other cell types investigated. This suggests that changes in actin structure are responsible for increased diffusion in hypoxic HeLa cells, although superresolution localization measurements in chemically fixed cells indicate that membrane proteins do not colocalize with F-actin under either experimental condition. These studies emphasize the importance of controls in single-molecule imaging measurements, and indicate that acute response to low oxygen in HeLa cells leads to dramatic changes in plasma membrane structure. It is possible that these changes are either a cause or consequence of phenotypic changes in solid tumor cells associated with increased drug resistance and malignancy.
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62
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Abstract
Galectins, a family of β-galactoside binding proteins, do not possess a signalling sequence to enter the endoplasmic reticulum as a starting point for the classical secretory pathway. They use a so-called unconventional secretion mechanism for translocation across the plasma membrane and/or into the lumen of transport vesicles. The β-galactoside binding protein galectin-3 is highly expressed in a variety of epithelial cell lines. Polarized MDCK cells secrete this lectin predominantly into the apical medium. The lectin re-enters the cell by non-clathrin mediated endocytosis and passages through endosomal organelles. This internalized galectin-3 plays an important role in apical protein trafficking by directing the subcellular targeting of apical glycoproteins via oligomerization into high molecular weight clusters, a process that can be fine-tuned by changes in the environmental pH. Following release at the apical plasma membrane, the lectin can reenter the cell for another round of recycling and apical protein sorting. This review will briefly address galectin-3-functions in epithelia and focus on distinct phases in apical recycling of the lectin.
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Affiliation(s)
- Ellena Hönig
- Department of Cell Biology and Cell Pathology, Philipps University of Marburg, Marburg, Germany
| | - Katharina Schneider
- Department of Cell Biology and Cell Pathology, Philipps University of Marburg, Marburg, Germany
| | - Ralf Jacob
- Department of Cell Biology and Cell Pathology, Philipps University of Marburg, Marburg, Germany.
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63
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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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64
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Paladino S, Lebreton S, Zurzolo C. Trafficking and Membrane Organization of GPI-Anchored Proteins in Health and Diseases. CURRENT TOPICS IN MEMBRANES 2015; 75:269-303. [PMID: 26015286 DOI: 10.1016/bs.ctm.2015.03.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are a class of lipid-anchored proteins attached to the membranes by a glycolipid anchor that is added, as posttranslation modification, in the endoplasmic reticulum. GPI-APs are expressed at the cell surface of eukaryotes where they play diverse vital functions. Like all plasma membrane proteins, GPI-APs must be correctly sorted along the different steps of the secretory pathway to their final destination. The presence of both a glycolipid anchor and a protein portion confers special trafficking features to GPI-APs. Here, we discuss the recent advances in the field of GPI-AP trafficking, focusing on the mechanisms regulating their biosynthetic pathway and plasma membrane organization. We also discuss how alterations of these mechanisms can result in different diseases. Finally, we will examine the strict relationship between the trafficking and function of GPI-APs in epithelial cells.
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Affiliation(s)
- Simona Paladino
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università Federico II, Napoli, Italy; CEINGE Biotecnologie Avanzate, Napoli, Italy
| | - Stéphanie Lebreton
- Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, Paris, France
| | - Chiara Zurzolo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università Federico II, Napoli, Italy; Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, Paris, France
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Albrecht D, Winterflood CM, Ewers H. Dual color single particle tracking via nanobodies. Methods Appl Fluoresc 2015; 3:024001. [DOI: 10.1088/2050-6120/3/2/024001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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66
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Bryant KL, Baird B, Holowka D. A novel fluorescence-based biosynthetic trafficking method provides pharmacologic evidence that PI4-kinase IIIα is important for protein trafficking from the endoplasmic reticulum to the plasma membrane. BMC Cell Biol 2015; 16:5. [PMID: 25886792 PMCID: PMC4355129 DOI: 10.1186/s12860-015-0049-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 01/21/2015] [Indexed: 02/07/2023] Open
Abstract
Background Biosynthetic trafficking of receptors and other membrane-associated proteins from the endoplasmic reticulum (ER) to the plasma membrane (PM) underlies the capacity of these proteins to participate in crucial cellular roles. Phosphoinositides have been shown to mediate distinct biological functions in cells, and phosphatidylinositol 4-phosphate (PI4P), in particular, has emerged as a key regulator of biosynthetic trafficking. Results To investigate the source of PI4P that orchestrates trafficking events, we developed a novel flow cytometry based method to monitor biosynthetic trafficking of transiently transfected proteins. We demonstrated that our method can be used to assess the trafficking of both type-1 transmembrane and GPI-linked proteins, and that it can accurately monitor the pharmacological disruption of biosynthetic trafficking with brefeldin A, a well-documented inhibitor of early biosynthetic trafficking. Furthermore, utilizing our newly developed method, we applied pharmacological inhibition of different isoforms of PI 4-kinase to reveal a role for a distinct pool of PI4P, synthesized by PI4KIIIα, in ER-to-PM trafficking. Conclusions Taken together, these findings provide evidence that a specific pool of PI4P plays a role in biosynthetic trafficking of two different classes of proteins from the ER to the Golgi complex. Furthermore, our simple, flow cytometry-based biosynthetic trafficking assay can be widely applied to the study of multiple classes of proteins and varied pharmacological and genetic perturbations.
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Affiliation(s)
- Kirsten L Bryant
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA. .,University of North Carolina, Chapel Hill, NC, 27514, USA.
| | - Barbara Baird
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
| | - David Holowka
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
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Schuberth CE, Tängemo C, Coneva C, Tischer C, Pepperkok R. Self-organization of core Golgi material is independent of COPII-mediated endoplasmic reticulum export. J Cell Sci 2015; 128:1279-93. [PMID: 25717003 DOI: 10.1242/jcs.154443] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Golgi is a highly organized and dynamic organelle that receives and distributes material from and to the endoplasmic reticulum (ER) and the endocytic pathway. One open question about Golgi organization is whether it is solely based on ER-to-Golgi transport. Here, we analyzed the kinetics of Golgi breakdown in the absence of COPII-dependent ER export with high temporal and spatial resolution using quantitative fluorescence microscopy. We found that Golgi breakdown occurred in two phases. While Golgi enzymes continuously redistributed to the ER, we consistently observed extensive Golgi fragmentation at the beginning of the breakdown, followed by microtubule-dependent formation of a Golgi remnant structure (phase 1). Further Golgi disintegration occurred less uniformly (phase 2). Remarkably, cisternal Golgi morphology was lost early in phase 1 and Golgi fragments instead corresponded to variably sized vesicle clusters. These breakdown intermediates were devoid of COPI-dependent recycling material, but contained typical 'core' Golgi components. Furthermore, Golgi breakdown intermediates were able to disassemble and reassemble following cell division, indicating that they retained important regulatory capabilities. Taken together, these findings support the view that Golgi self-organization exists independently of ER-to-Golgi transport.
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Affiliation(s)
- Christian E Schuberth
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstr. 1, 69117 Heidelberg, Germany Institute of Cell Dynamics and Imaging, University of Muenster, von-Esmarch-Str. 56, 48149 Muenster, Germany Cells in Motion Cluster of Excellence (EXC1003-CiM), University of Muenster, von-Esmarch-Str. 56, 48149 Muenster, Germany
| | - Carolina Tängemo
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Cvetalina Coneva
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Christian Tischer
- Advanced Light Microscopy Facility, European Molecular Biology Laboratory (EMBL), Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Rainer Pepperkok
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstr. 1, 69117 Heidelberg, Germany Advanced Light Microscopy Facility, European Molecular Biology Laboratory (EMBL), Meyerhofstr. 1, 69117 Heidelberg, Germany
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Whitt MA, Cox ME, Kansal R, Cox JV. Kinetically Distinct Sorting Pathways through the Golgi Exhibit Different Requirements for Arf1. Traffic 2015; 16:267-83. [DOI: 10.1111/tra.12248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 11/26/2014] [Accepted: 11/26/2014] [Indexed: 01/10/2023]
Affiliation(s)
- Michael A. Whitt
- Department of Microbiology, Immunology, and Biochemistry; University of Tennessee Health Science Center; Memphis TN 38163 USA
| | - Michelle E. Cox
- Department of Microbiology, Immunology, and Biochemistry; University of Tennessee Health Science Center; Memphis TN 38163 USA
| | - Rita Kansal
- Department of Microbiology, Immunology, and Biochemistry; University of Tennessee Health Science Center; Memphis TN 38163 USA
| | - John V. Cox
- Department of Microbiology, Immunology, and Biochemistry; University of Tennessee Health Science Center; Memphis TN 38163 USA
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Lund FW, Jensen MLV, Christensen T, Nielsen GK, Heegaard CW, Wüstner D. SpatTrack: An Imaging Toolbox for Analysis of Vesicle Motility and Distribution in Living Cells. Traffic 2014; 15:1406-29. [DOI: 10.1111/tra.12228] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 09/16/2014] [Accepted: 09/17/2014] [Indexed: 01/01/2023]
Affiliation(s)
- Frederik W. Lund
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; DK-5230 Odense M Denmark
- Department of Biochemistry; Weill Medical College of Cornell University; York Ave. 1300 10065 NY USA
| | - Maria Louise V. Jensen
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; DK-5230 Odense M Denmark
| | - Tanja Christensen
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; DK-5230 Odense M Denmark
| | - Gitte K. Nielsen
- Department of Biomedicine; University of Aarhus; DK-8000 Aarhus C. Denmark
| | - Christian W. Heegaard
- Department of Molecular Biology and Genetics; University of Aarhus; DK-8000 Aarhus C. Denmark
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; DK-5230 Odense M Denmark
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70
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Jaensch N, Corrêa IR, Watanabe R. Stable cell surface expression of GPI-anchored proteins, but not intracellular transport, depends on their fatty acid structure. Traffic 2014; 15:1305-29. [PMID: 25196094 DOI: 10.1111/tra.12224] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 09/02/2014] [Accepted: 09/02/2014] [Indexed: 11/28/2022]
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are a class of lipid anchored proteins expressed on the cell surface of eukaryotes. The potential interaction of GPI-APs with ordered lipid domains enriched in cholesterol and sphingolipids has been proposed to function in the intracellular transport of these lipid anchored proteins. Here, we examined the biological importance of two saturated fatty acids present in the phosphatidylinositol moiety of GPI-APs. These fatty acids are introduced by the action of lipid remodeling enzymes and required for the GPI-AP association within ordered lipid domains. We found that the fatty acid remodeling is not required for either efficient Golgi-to-plasma membrane transport or selective endocytosis via GPI-enriched early endosomal compartment (GEEC)/ clathrin-independent carrier (CLIC) pathway, whereas cholesterol depletion significantly affects both pathways independent of their fatty acid structure. Therefore, the mechanism of cholesterol dependence does not appear to be related to the interaction with ordered lipid domains mediated by two saturated fatty acids. Furthermore, cholesterol extraction drastically releases the unremodeled GPI-APs carrying an unsaturated fatty acid from the cell surface, but not remodeled GPI-APs carrying two saturated fatty acids. This underscores the essential role of lipid remodeling to ensure a stable membrane association of GPI-APs particularly under potential membrane lipid perturbation.
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Affiliation(s)
- Nina Jaensch
- Department of Biochemistry, University of Geneva Sciences II, CH1-1211 Geneva, Switzerland
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71
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Affiliation(s)
- Yusong Guo
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3200;
| | - Daniel W. Sirkis
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3200;
| | - Randy Schekman
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3200;
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72
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Vildanova MS, Wang W, Smirnova EA. Specific organization of Golgi apparatus in plant cells. BIOCHEMISTRY (MOSCOW) 2014; 79:894-906. [DOI: 10.1134/s0006297914090065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Ronchi P, Tischer C, Acehan D, Pepperkok R. Positive feedback between Golgi membranes, microtubules and ER exit sites directs de novo biogenesis of the Golgi. J Cell Sci 2014; 127:4620-33. [PMID: 25189616 DOI: 10.1242/jcs.150474] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Golgi complex is the central organelle of the secretory pathway. It undergoes dynamic changes during the cell cycle, but how it acquires and maintains its complex structure is unclear. To address this question, we have used laser nanosurgery to deplete BSC1 cells of the Golgi complex and have monitored its biogenesis by quantitative time-lapse microscopy and correlative electron microscopy. After Golgi depletion, endoplasmic reticulum (ER) export is inhibited and the number of ER exit sites (ERES) is reduced and does not increase for several hours. Occasional fusion of small post-ER carriers to form the first larger structures triggers a rapid and drastic growth of Golgi precursors, due to the capacity of these structures to attract more carriers by microtubule nucleation and to stimulate ERES biogenesis. Increasing the chances of post-ER carrier fusion close to ERES by depolymerizing microtubules results in the acceleration of Golgi and ERES biogenesis. Taken together, on the basis of our results, we propose a self-organizing principle of the early secretory pathway that integrates Golgi biogenesis, ERES biogenesis and the organization of the microtubule network by positive-feedback loops.
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Affiliation(s)
- Paolo Ronchi
- European Molecular Biology Laboratory (EMBL), Cell biology and biophysics unit
| | - Christian Tischer
- European Molecular Biology Laboratory (EMBL), Advanced Light Microscopy
| | - Devrim Acehan
- European Molecular Biology Laboratory (EMBL), Electron Microscopy Core Facilities, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Rainer Pepperkok
- European Molecular Biology Laboratory (EMBL), Cell biology and biophysics unit European Molecular Biology Laboratory (EMBL), Advanced Light Microscopy
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Tucker CL, Vrana JD, Kennedy MJ. Tools for controlling protein interactions using light. ACTA ACUST UNITED AC 2014; 64:17.16.1-20. [PMID: 25181301 DOI: 10.1002/0471143030.cb1716s64] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Genetically encoded actuators that allow control of protein-protein interactions using light, termed 'optical dimerizers', are emerging as new tools for experimental biology. In recent years, numerous new and versatile dimerizer systems have been developed. Here we discuss the design of optical dimerizer experiments, including choice of a dimerizer system, photoexcitation sources, and the coordinate use of imaging reporters. We provide detailed protocols for experiments using two dimerization systems we previously developed, CRY2/CIB and UVR8/UVR8, for use in controlling transcription, protein localization, and protein secretion using light. Additionally, we provide instructions and software for constructing a pulse-controlled LED device for use in experiments requiring extended light treatments.
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Affiliation(s)
- Chandra L Tucker
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, Colorado
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Diaz-Rohrer B, Levental KR, Levental I. Rafting through traffic: Membrane domains in cellular logistics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:3003-3013. [PMID: 25130318 DOI: 10.1016/j.bbamem.2014.07.029] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/28/2014] [Accepted: 07/31/2014] [Indexed: 01/03/2023]
Abstract
The intricate and tightly regulated organization of eukaryotic cells into spatially and functionally distinct membrane-bound compartments is a defining feature of complex organisms. These compartments are defined by their lipid and protein compositions, with their limiting membrane as the functional interface to the rest of the cell. Thus, proper segregation of membrane proteins and lipids is necessary for the maintenance of organelle identity, and this segregation must be maintained despite extensive, rapid membrane exchange between compartments. Sorting processes of high efficiency and fidelity are required to avoid potentially deleterious mis-targeting and maintain cellular function. Although much molecular machinery associated with membrane traffic (i.e. membrane budding/fusion/fission) has been characterized both structurally and biochemically, the mechanistic details underlying the tightly regulated distribution of membranes between subcellular locations remain to be elucidated. This review presents evidence for the role of ordered lateral membrane domains known as lipid rafts in both biosynthetic sorting in the late secretory pathway, as well as endocytosis and recycling to/from the plasma membrane. Although such evidence is extensive and the involvement of membrane domains in sorting is definitive, specific mechanistic details for raft-dependent sorting processes remain elusive.
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Affiliation(s)
- Blanca Diaz-Rohrer
- University of Texas Health Science Center at Houston, 6431 Fannin St, Houston, TX 77030, USA
| | - Kandice R Levental
- University of Texas Health Science Center at Houston, 6431 Fannin St, Houston, TX 77030, USA
| | - Ilya Levental
- University of Texas Health Science Center at Houston, 6431 Fannin St, Houston, TX 77030, USA; Cancer Prevention and Research Institute of Texas, USA.
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76
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Hettich J, Ryan SD, de Souza ON, Saraiva Macedo Timmers LF, Tsai S, Atai NA, da Hora CC, Zhang X, Kothary R, Snapp E, Ericsson M, Grundmann K, Breakefield XO, Nery FC. Biochemical and cellular analysis of human variants of the DYT1 dystonia protein, TorsinA/TOR1A. Hum Mutat 2014; 35:1101-13. [PMID: 24930953 DOI: 10.1002/humu.22602] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 06/04/2014] [Indexed: 12/24/2022]
Abstract
Early-onset dystonia is associated with the deletion of one of a pair of glutamic acid residues (c.904_906delGAG/c.907_909delGAG; p.Glu302del/Glu303del; ΔE 302/303) near the carboxyl-terminus of torsinA, a member of the AAA(+) protein family that localizes to the endoplasmic reticulum lumen and nuclear envelope. This deletion commonly underlies early-onset DYT1 dystonia. While the role of the disease-causing mutation, torsinAΔE, has been established through genetic association studies, it is much less clear whether other rare human variants of torsinA are pathogenic. Two missense variations have been described in single patients: R288Q (c.863G>A; p.Arg288Gln; R288Q) identified in a patient with onset of severe generalized dystonia and myoclonus since infancy and F205I (c.613T>A, p.Phe205Ile; F205I) in a psychiatric patient with late-onset focal dystonia. In this study, we have undertaken a series of analyses comparing the biochemical and cellular effects of these rare variants to torsinAΔE and wild-type (wt) torsinA to reveal whether there are common dysfunctional features. The results revealed that the variants, R288Q and F205I, are more similar in their properties to torsinAΔE protein than to torsinAwt. These findings provide functional evidence for the potential pathogenic nature of these rare sequence variants in the TOR1A gene, thus implicating these pathologies in the development of dystonia.
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Affiliation(s)
- Jasmin Hettich
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts; Department of Medical Genetics and Applied Genomics, University of Tuebingen, Tübingen, Germany
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Axonal targeting of the serotonin transporter in cultured rat dorsal raphe neurons is specified by SEC24C-dependent export from the endoplasmic reticulum. J Neurosci 2014; 34:6344-6351. [PMID: 24790205 DOI: 10.1523/jneurosci.2991-13.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Export of the serotonin transporter (SERT) from the endoplasmic reticulum (ER) is mediated by the SEC24C isoform of the coatomer protein-II complex. SERT must enter the axonal compartment and reach the presynaptic specialization to perform its function, i.e., the inward transport of serotonin. Refilling of vesicles is contingent on the operation of an efficient relay between SERT and the vesicular monoamine transporter-2 (VMAT2). Here, we visualized the distribution of both endogenously expressed SERT and heterologously expressed variants of human SERT in dissociated rat dorsal raphe neurons to examine the role of SEC24C-dependent ER export in axonal targeting of SERT. We conclude that axonal delivery of SERT is contingent on recruitment of SEC24C in the ER. This conclusion is based on the following observations. (1) Both endogenous and heterologously expressed SERT were delivered to the extensive axonal arborizations and accumulated in bouton-like structures. (2) In contrast, SERT-(607)RI(608)-AA, in which the binding site of SEC24C is disrupted, remained confined to the microtubule-associated protein 2-positive somatodendritic compartment. (3) The overexpression of dominant-negative SEC24C-D(796)V/D(797)N (but not of the corresponding SEC24D mutant) redirected both endogenous SERT and heterologously expressed yellow fluorescent protein-SERT from axons to the somatodendritic region. (4) SERT-K(610)Y, which harbors a mutation converting it into an SEC24D client, was rerouted from the axonal to the somatodendritic compartment by dominant-negative SEC24D. In contrast, axonal targeting of the VMAT2 was disrupted by neither dominant-negative SEC24C nor dominant-negative SEC24D. This suggests that SERT and VMAT2 reach the presynaptic specialization by independent routes.
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78
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Schwarzer R, Levental I, Gramatica A, Scolari S, Buschmann V, Veit M, Herrmann A. The cholesterol-binding motif of the HIV-1 glycoprotein gp41 regulates lateral sorting and oligomerization. Cell Microbiol 2014; 16:1565-81. [PMID: 24844300 DOI: 10.1111/cmi.12314] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/24/2014] [Accepted: 05/13/2014] [Indexed: 12/12/2022]
Abstract
Enveloped viruses often use membrane lipid rafts to assemble and bud, augment infection and spread efficiently. However, the molecular bases and functional consequences of the partitioning of viral glycoproteins into microdomains remain intriguing questions in virus biology. Here, we measured Foerster resonance energy transfer by fluorescence lifetime imaging microscopy (FLIM-FRET) to study the role of distinct membrane proximal regions of the human immunodeficiency virus glycoprotein gp41 for lipid raft partitioning in living Chinese hamster ovary cells (CHO-K1). Gp41 was labelled with a fluorescent protein at the exoplasmic face of the membrane, preventing any interference of the fluorophore with the proposed role of the transmembrane and cytoplasmic domains in lateral organization of gp41. Raft localization was deduced from interaction with an established raft marker, a fluorescently tagged glycophosphatidylinositol anchor and the cholesterol recognition amino acid consensus (CRAC) was identified as the crucial lateral sorting determinant in CHO-K1 cells. Interestingly, the raft association of gp41 indicates a substantial cell-to-cell heterogeneity of the plasma membrane microdomains. In complementary fluorescence polarization microscopy, a distinct CRAC requirement was found for the oligomerization of the gp41 variants. Our data provide further insight into the molecular basis and biological implications of the cholesterol dependent lateral sorting of viral glycoproteins for virus assembly at cellular membranes.
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Affiliation(s)
- Roland Schwarzer
- Department of Biology, Molecular Biophysics, Humboldt University, 10115, Berlin, Germany
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Muñiz M, Zurzolo C. Sorting of GPI-anchored proteins from yeast to mammals--common pathways at different sites? J Cell Sci 2014; 127:2793-801. [PMID: 24906797 DOI: 10.1242/jcs.148056] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are luminal secretory cargos that are attached by a post-translational glycolipid modification, the GPI anchor, to the external leaflet of the plasma membrane. GPI-APs are conserved among eukaryotes and possess many diverse and vital functions for which the GPI membrane attachment appears to be essential. The presence of the GPI anchor and its subsequent modifications along the secretory pathway confer to the anchored proteins unique trafficking properties that make GPI-APs an exceptional system to study mechanisms of sorting. In this Commentary, we discuss the recent advances in the field of GPI-AP sorting focusing on the mechanisms operating at the level of the exit from the ER and from the trans-Golgi network (TGN), which take place, respectively, in yeast and in polarized mammalian cells. By considering the similarities and differences between these two sorting events, we present unifying principles that appear to work at different sorting stations and in different organisms.
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Affiliation(s)
- Manuel Muñiz
- Department of Cell Biology, University of Seville, Avda. Reina Mercedes s/n 41012 Seville, Spain
| | - Chiara Zurzolo
- Institut Pasteur, Unité de Trafic Membranaire et Pathogénèse, 75724 Paris CEDEX 15, France
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80
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Chaudhary N, Gomez GA, Howes MT, Lo HP, McMahon KA, Rae JA, Schieber NL, Hill MM, Gaus K, Yap AS, Parton RG. Endocytic crosstalk: cavins, caveolins, and caveolae regulate clathrin-independent endocytosis. PLoS Biol 2014; 12:e1001832. [PMID: 24714042 PMCID: PMC3979662 DOI: 10.1371/journal.pbio.1001832] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 02/25/2014] [Indexed: 12/18/2022] Open
Abstract
Caveolar proteins and caveolae negatively regulate a second clathrin-independent endocytic CLIC/GEEC pathway; caveolin-1 affects membrane diffusion properties of raft-associated CLIC cargo, and the scaffolding domain of caveolin-1 is required and sufficient for endocytic inhibition. Several studies have suggested crosstalk between different clathrin-independent endocytic pathways. However, the molecular mechanisms and functional relevance of these interactions are unclear. Caveolins and cavins are crucial components of caveolae, specialized microdomains that also constitute an endocytic route. Here we show that specific caveolar proteins are independently acting negative regulators of clathrin-independent endocytosis. Cavin-1 and Cavin-3, but not Cavin-2 or Cavin-4, are potent inhibitors of the clathrin-independent carriers/GPI-AP enriched early endosomal compartment (CLIC/GEEC) endocytic pathway, in a process independent of caveola formation. Caveolin-1 (CAV1) and CAV3 also inhibit the CLIC/GEEC pathway upon over-expression. Expression of caveolar protein leads to reduction in formation of early CLIC/GEEC carriers, as detected by quantitative electron microscopy analysis. Furthermore, the CLIC/GEEC pathway is upregulated in cells lacking CAV1/Cavin-1 or with reduced expression of Cavin-1 and Cavin-3. Inhibition by caveolins can be mimicked by the isolated caveolin scaffolding domain and is associated with perturbed diffusion of lipid microdomain components, as revealed by fluorescence recovery after photobleaching (FRAP) studies. In the absence of cavins (and caveolae) CAV1 is itself endocytosed preferentially through the CLIC/GEEC pathway, but the pathway loses polarization and sorting attributes with consequences for membrane dynamics and endocytic polarization in migrating cells and adult muscle tissue. We also found that noncaveolar Cavin-1 can act as a modulator for the activity of the key regulator of the CLIC/GEEC pathway, Cdc42. This work provides new insights into the regulation of noncaveolar clathrin-independent endocytosis by specific caveolar proteins, illustrating multiple levels of crosstalk between these pathways. We show for the first time a role for specific cavins in regulating the CLIC/GEEC pathway, provide a new tool to study this pathway, identify caveola-independent functions of the cavins and propose a novel mechanism for inhibition of the CLIC/GEEC pathway by caveolin. Endocytosis is the process that allows cells to take up molecules from the environment. Several endocytic pathways exist in mammalian cells. While the best understood endocytic pathway uses clathrin, recent years have seen a great increase in our understanding of clathrin-independent endocytic pathways. Here we characterize the crosstalk between caveolae, flask-shaped specialized microdomains present at the plasma membrane, and a second clathrin-independent pathway, the CLIC/GEEC Cdc42-regulated endocytic pathway. These pathways are segregated in migrating cells with caveolae at the rear and CLIC/GEEC endocytosis at the leading edge. Here we find that specific caveolar proteins, caveolins and cavins, can also negatively regulate the CLIC/GEEC pathway. With the help of several techniques, including quantitative electron microscopy analysis and real-time live-cell imaging, we demonstrate that expression of caveolar proteins affects early carrier formation, causes cellular lipid changes, and changes the activity of the key regulator of the CLIC/GEEC pathway, Cdc42. The functional consequences of loss of caveolar proteins on the CLIC/GEEC pathway included inhibition of polarized cell migration and increased endocytosis in tissue explants.
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Affiliation(s)
- Natasha Chaudhary
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Guillermo A. Gomez
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Mark T. Howes
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Harriet P. Lo
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Kerrie-Ann McMahon
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - James A. Rae
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Nicole L. Schieber
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Michelle M. Hill
- The University of Queensland, Diamantina Institute, Queensland, Australia
| | - Katharina Gaus
- The University of New South Wales, Centre for Vascular Research and Australian Centre for Nanomedicine, New South Wales, Australia
| | - Alpha S. Yap
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Robert G. Parton
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
- Centre for Microscopy and Microanalysis, Queensland, Australia
- * E-mail:
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Stoops EH, Caplan MJ. Trafficking to the apical and basolateral membranes in polarized epithelial cells. J Am Soc Nephrol 2014; 25:1375-86. [PMID: 24652803 DOI: 10.1681/asn.2013080883] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Renal epithelial cells must maintain distinct protein compositions in their apical and basolateral membranes in order to perform their transport functions. The creation of these polarized protein distributions depends on sorting signals that designate the trafficking route and site of ultimate functional residence for each protein. Segregation of newly synthesized apical and basolateral proteins into distinct carrier vesicles can occur at the trans-Golgi network, recycling endosomes, or a growing assortment of stations along the cellular trafficking pathway. The nature of the specific sorting signal and the mechanism through which it is interpreted can influence the route a protein takes through the cell. Cell type-specific variations in the targeting motifs of a protein, as are evident for Na,K-ATPase, demonstrate a remarkable capacity to adapt sorting pathways to different developmental states or physiologic requirements. This review summarizes our current understanding of apical and basolateral trafficking routes in polarized epithelial cells.
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Affiliation(s)
- Emily H Stoops
- Departments of Cellular & Molecular Physiology and Cell Biology, Yale University School of Medicine, New Haven, Connecticut
| | - Michael J Caplan
- Departments of Cellular & Molecular Physiology and Cell Biology, Yale University School of Medicine, New Haven, Connecticut
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82
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Luz M, Spannl-Müller S, Özhan G, Kagermeier-Schenk B, Rhinn M, Weidinger G, Brand M. Dynamic association with donor cell filopodia and lipid-modification are essential features of Wnt8a during patterning of the zebrafish neuroectoderm. PLoS One 2014; 9:e84922. [PMID: 24427298 PMCID: PMC3888416 DOI: 10.1371/journal.pone.0084922] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 11/20/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Wnt proteins are conserved signaling molecules that regulate pattern formation during animal development. Many Wnt proteins are post-translationally modified by addition of lipid adducts. Wnt8a provides a crucial signal for patterning the anteroposterior axis of the developing neural plate in vertebrates. However, it is not clear how this protein propagates from its source, the blastoderm margin, to the target cells in the prospective neural plate, and how lipid-modifications might influence Wnt8a propagation and activity. RESULTS We have dynamically imaged biologically active, fluorescently tagged Wnt8a in living zebrafish embryos. We find that Wnt8a localizes to membrane-associated, punctate structures in live tissue. In Wnt8a expressing cells, these puncta are found on filopodial cellular processes, from where the protein can be released. In addition, Wnt8a is found colocalized with Frizzled receptor-containing clusters on signal receiving cells. Combining in vitro and in vivo assays, we compare the roles of conserved Wnt8a residues in cell and non-cell-autonomous signaling activity and secretion. Non-signaling Wnt8 variants show these residues can regulate Wnt8a distribution in producing cell membranes and filopodia as well as in the receiving tissue. CONCLUSIONS Together, our results show that Wnt8a forms dynamic clusters found on filopodial donor cell and on signal receiving cell membranes. Moreover, they demonstrate a differential requirement of conserved residues in Wnt8a protein for distribution in producing cells and receiving tissue and signaling activity during neuroectoderm patterning.
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Affiliation(s)
- Marta Luz
- Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Stephanie Spannl-Müller
- Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Günes Özhan
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | | | - Muriel Rhinn
- Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Gilbert Weidinger
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Michael Brand
- Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
- * E-mail:
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83
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Stahlschmidt W, Robertson MJ, Robinson PJ, McCluskey A, Haucke V. Clathrin terminal domain-ligand interactions regulate sorting of mannose 6-phosphate receptors mediated by AP-1 and GGA adaptors. J Biol Chem 2014; 289:4906-18. [PMID: 24407285 DOI: 10.1074/jbc.m113.535211] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Clathrin plays important roles in intracellular membrane traffic including endocytosis of plasma membrane proteins and receptors and protein sorting between the trans-Golgi network (TGN) and endosomes. Whether clathrin serves additional roles in receptor recycling, degradative sorting, or constitutive secretion has remained somewhat controversial. Here we have used acute pharmacological perturbation of clathrin terminal domain (TD) function to dissect the role of clathrin in intracellular membrane traffic. We report that internalization of major histocompatibility complex I (MHCI) is inhibited in cells depleted of clathrin or its major clathrin adaptor complex 2 (AP-2), a phenotype mimicked by application of Pitstop® inhibitors of clathrin TD function. Hence, MHCI endocytosis occurs via a clathrin/AP-2-dependent pathway. Acute perturbation of clathrin also impairs the dynamics of intracellular clathrin/adaptor complex 1 (AP-1)- or GGA (Golgi-localized, γ-ear-containing, Arf-binding protein)-coated structures at the TGN/endosomal interface, resulting in the peripheral dispersion of mannose 6-phosphate receptors. By contrast, secretory traffic of vesicular stomatitis virus G protein, recycling of internalized transferrin from endosomes, or degradation of EGF receptor proceeds unperturbed in cells with impaired clathrin TD function. These data indicate that clathrin is required for the function of AP-1- and GGA-coated carriers at the TGN but may be dispensable for outward traffic en route to the plasma membrane.
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Affiliation(s)
- Wiebke Stahlschmidt
- From the Leibniz-Institut für Molekulare Pharmakologie, 13125 Berlin-Buch, Germany
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84
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Using replication defective viruses to analyze membrane trafficking in polarized epithelial cells. Methods Cell Biol 2013. [PMID: 24295304 DOI: 10.1016/b978-0-12-417164-0.00008-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Epithelial cells in culture, especially once they are polarized, are extremely hard to manipulate by transient transfection methods. The use of replication defective adenoviruses for gene expression or replication defective retroviruses or lentiviruses to express shRNA for gene knockdown provides efficient tools to manipulate gene expression patterns even in hard-to-transfect cell lines. One of the advantages of using defective adenoviruses for gene expression is that once the virus has been generated, it can easily be applied to a wide variety of cells. In addition, replication defective retro- and lentiviruses are used to stably deplete proteins from cell lines, which subsequently may be used for analyzing the polarized surface delivery of receptors that may be expressed using defective adenoviruses. The latter approach is especially useful if the expressed shRNA also encodes GFP for easy assessment of shRNA-expressing cells. Thus the use of defective viruses in epithelial cell research is convenient. This makes a detailed infection protocol a research tool that would be valuable to many laboratories. Here we describe in detail how cells are infected with defective retro- or lentiviruses and subsequently selected for stable gene knockdown. We then describe how these cells may be used for infection with defective adenoviruses and the subsequent analyses.
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85
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Abstract
Hepatocytes, like other epithelia, are situated at the interface between the organism's exterior and the underlying internal milieu and organize the vectorial exchange of macromolecules between these two spaces. To mediate this function, epithelial cells, including hepatocytes, are polarized with distinct luminal domains that are separated by tight junctions from lateral domains engaged in cell-cell adhesion and from basal domains that interact with the underlying extracellular matrix. Despite these universal principles, hepatocytes distinguish themselves from other nonstriated epithelia by their multipolar organization. Each hepatocyte participates in multiple, narrow lumina, the bile canaliculi, and has multiple basal surfaces that face the endothelial lining. Hepatocytes also differ in the mechanism of luminal protein trafficking from other epithelia studied. They lack polarized protein secretion to the luminal domain and target single-spanning and glycosylphosphatidylinositol-anchored bile canalicular membrane proteins via transcytosis from the basolateral domain. We compare this unique hepatic polarity phenotype with that of the more common columnar epithelial organization and review our current knowledge of the signaling mechanisms and the organization of polarized protein trafficking that govern the establishment and maintenance of hepatic polarity. The serine/threonine kinase LKB1, which is activated by the bile acid taurocholate and, in turn, activates adenosine monophosphate kinase-related kinases including AMPK1/2 and Par1 paralogues has emerged as a key determinant of hepatic polarity. We propose that the absence of a hepatocyte basal lamina and differences in cell-cell adhesion signaling that determine the positioning of tight junctions are two crucial determinants for the distinct hepatic and columnar polarity phenotypes.
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Affiliation(s)
- Aleksandr Treyer
- Albert Einstein College of Medicine, Department of Developmental and Molecular Biology, Bronx, New York, USA
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86
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Börner K, Niopek D, Cotugno G, Kaldenbach M, Pankert T, Willemsen J, Zhang X, Schürmann N, Mockenhaupt S, Serva A, Hiet MS, Wiedtke E, Castoldi M, Starkuviene V, Erfle H, Gilbert DF, Bartenschlager R, Boutros M, Binder M, Streetz K, Kräusslich HG, Grimm D. Robust RNAi enhancement via human Argonaute-2 overexpression from plasmids, viral vectors and cell lines. Nucleic Acids Res 2013; 41:e199. [PMID: 24049077 PMCID: PMC3834839 DOI: 10.1093/nar/gkt836] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 08/21/2013] [Accepted: 08/25/2013] [Indexed: 12/31/2022] Open
Abstract
As the only mammalian Argonaute protein capable of directly cleaving mRNAs in a small RNA-guided manner, Argonaute-2 (Ago2) is a keyplayer in RNA interference (RNAi) silencing via small interfering (si) or short hairpin (sh) RNAs. It is also a rate-limiting factor whose saturation by si/shRNAs limits RNAi efficiency and causes numerous adverse side effects. Here, we report a set of versatile tools and widely applicable strategies for transient or stable Ago2 co-expression, which overcome these concerns. Specifically, we engineered plasmids and viral vectors to co-encode a codon-optimized human Ago2 cDNA along with custom shRNAs. Furthermore, we stably integrated this Ago2 cDNA into a panel of standard human cell lines via plasmid transfection or lentiviral transduction. Using various endo- or exogenous targets, we demonstrate the potential of all three strategies to boost mRNA silencing efficiencies in cell culture by up to 10-fold, and to facilitate combinatorial knockdowns. Importantly, these robust improvements were reflected by augmented RNAi phenotypes and accompanied by reduced off-targeting effects. We moreover show that Ago2/shRNA-co-encoding vectors can enhance and prolong transgene silencing in livers of adult mice, while concurrently alleviating hepatotoxicity. Our customizable reagents and avenues should broadly improve future in vitro and in vivo RNAi experiments in mammalian systems.
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Affiliation(s)
- Kathleen Börner
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Dominik Niopek
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Gabriella Cotugno
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Michaela Kaldenbach
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Teresa Pankert
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Joschka Willemsen
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Xian Zhang
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Nina Schürmann
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Stefan Mockenhaupt
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Andrius Serva
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Marie-Sophie Hiet
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Ellen Wiedtke
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Mirco Castoldi
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Vytaute Starkuviene
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Holger Erfle
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Daniel F. Gilbert
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Michael Boutros
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Marco Binder
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Konrad Streetz
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Dirk Grimm
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany, Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany, Department of Medicine III, University Hospital Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany, Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany, Division Signaling and Functional Genomics, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany and Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, Heidelberg University Hospital, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
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Kanerva K, Uronen RL, Blom T, Li S, Bittman R, Lappalainen P, Peränen J, Raposo G, Ikonen E. LDL cholesterol recycles to the plasma membrane via a Rab8a-Myosin5b-actin-dependent membrane transport route. Dev Cell 2013; 27:249-62. [PMID: 24209575 DOI: 10.1016/j.devcel.2013.09.016] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/09/2013] [Accepted: 09/16/2013] [Indexed: 12/27/2022]
Abstract
Mammalian cells acquire cholesterol, a major membrane constituent, via low-density lipoprotein (LDL) uptake. However, the mechanisms by which LDL cholesterol reaches the plasma membrane (PM) have remained obscure. Here, we applied LDL labeled with BODIPY cholesteryl linoleate to identify this pathway in living cells. The egress of BODIPY cholesterol (BC) from late endosomal (LE) organelles was dependent on acid lipase and Niemann-Pick C1 (NPC1) protein, as for natural cholesterol. We show that NPC1 was needed to recruit Rab8a to BC-containing LEs, and Rab8a enhanced the motility and segregation of BC- and CD63-positive organelles from lysosomes. The BC carriers docked to the cortical actin by a Rab8a- and Myosin5b (Myo5b)-dependent mechanism, typically in the proximity of focal adhesions (FAs). LDL increased the number and dynamics of FAs and stimulated cell migration in an acid lipase, NPC1, and Rab8a-dependent fashion, providing evidence that this cholesterol delivery route to the PM is important for cell movement.
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Affiliation(s)
- Kristiina Kanerva
- Institute of Biomedicine, Anatomy, University of Helsinki, FI-00014 Helsinki, Finland; Minerva Foundation Institute for Medical Research, FI-00290 Helsinki, Finland
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88
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Myeni S, Child R, Ng TW, Kupko JJ, Wehrly TD, Porcella SF, Knodler LA, Celli J. Brucella modulates secretory trafficking via multiple type IV secretion effector proteins. PLoS Pathog 2013; 9:e1003556. [PMID: 23950720 PMCID: PMC3738490 DOI: 10.1371/journal.ppat.1003556] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 06/27/2013] [Indexed: 01/18/2023] Open
Abstract
The intracellular pathogenic bacterium Brucella generates a replicative vacuole (rBCV) derived from the endoplasmic reticulum via subversion of the host cell secretory pathway. rBCV biogenesis requires the expression of the Type IV secretion system (T4SS) VirB, which is thought to translocate effector proteins that modulate membrane trafficking along the endocytic and secretory pathways. To date, only a few T4SS substrates have been identified, whose molecular functions remain unknown. Here, we used an in silico screen to identify putative T4SS effector candidate proteins using criteria such as limited homology in other bacterial genera, the presence of features similar to known VirB T4SS effectors, GC content and presence of eukaryotic-like motifs. Using β-lactamase and CyaA adenylate cyclase reporter assays, we identified eleven proteins translocated into host cells by Brucella, five in a VirB T4SS-dependent manner, namely BAB1_0678 (BspA), BAB1_0712 (BspB), BAB1_0847 (BspC), BAB1_1671 (BspE) and BAB1_1948 (BspF). A subset of the translocated proteins targeted secretory pathway compartments when ectopically expressed in HeLa cells, and the VirB effectors BspA, BspB and BspF inhibited protein secretion. Brucella infection also impaired host protein secretion in a process requiring BspA, BspB and BspF. Single or combined deletions of bspA, bspB and bspF affected Brucella ability to replicate in macrophages and persist in the liver of infected mice. Taken together, these findings demonstrate that Brucella modulates secretory trafficking via multiple T4SS effector proteins that likely act coordinately to promote Brucella pathogenesis.
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Affiliation(s)
- Sebenzile Myeni
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Robert Child
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Tony W. Ng
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - John J. Kupko
- Genomics Unit, Research Technologies Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Tara D. Wehrly
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Stephen F. Porcella
- Genomics Unit, Research Technologies Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Leigh A. Knodler
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Jean Celli
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
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89
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Fox PD, Haberkorn CJ, Weigel AV, Higgins JL, Akin EJ, Kennedy MJ, Krapf D, Tamkun MM. Plasma membrane domains enriched in cortical endoplasmic reticulum function as membrane protein trafficking hubs. Mol Biol Cell 2013; 24:2703-13. [PMID: 23864710 PMCID: PMC3756922 DOI: 10.1091/mbc.e12-12-0895] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In mammalian cells, the cortical endoplasmic reticulum (cER) is a network of tubules and cisterns that lie in close apposition to the plasma membrane (PM). We provide evidence that PM domains enriched in underlying cER function as trafficking hubs for insertion and removal of PM proteins in HEK 293 cells. By simultaneously visualizing cER and various transmembrane protein cargoes with total internal reflectance fluorescence microscopy, we demonstrate that the majority of exocytotic delivery events for a recycled membrane protein or for a membrane protein being delivered to the PM for the first time occur at regions enriched in cER. Likewise, we observed recurring clathrin clusters and functional endocytosis of PM proteins preferentially at the cER-enriched regions. Thus the cER network serves to organize the molecular machinery for both insertion and removal of cell surface proteins, highlighting a novel role for these unique cellular microdomains in membrane trafficking.
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Affiliation(s)
- Philip D Fox
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
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90
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Chia PZC, Toh WH, Sharples R, Gasnereau I, Hill AF, Gleeson PA. Intracellular itinerary of internalised β-secretase, BACE1, and its potential impact on β-amyloid peptide biogenesis. Traffic 2013; 14:997-1013. [PMID: 23773724 DOI: 10.1111/tra.12088] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 06/11/2013] [Accepted: 06/14/2013] [Indexed: 01/17/2023]
Abstract
β-Secretase (BACE1) cleavage of the amyloid precursor protein (APP) represents the initial step in the formation of the Alzheimer's disease associated amyloidogenic Aβ peptide. Substantive evidence indicates that APP processing by BACE1 is dependent on intracellular sorting of this enzyme. Nonetheless, knowledge of the intracellular trafficking pathway of internalised BACE1 remains in doubt. Here we show that cell surface BACE1 is rapidly internalised by the AP2/clathrin dependent pathway in transfected cells and traffics to early endosomes and Rab11-positive, juxtanuclear recycling endosomes, with very little transported to the TGN as has been previously suggested. Moreover, BACE1 is predominantly localised to the early and recycling endosome compartments in different cell types, including neuronal cells. In contrast, the majority of internalised wild-type APP traffics to late endosomes/lysosomes. To explore the relevance of the itinerary of BACE1 on APP processing, we generated a BACE1 chimera containing the cytoplasmic tail of TGN38 (BACE/TGN38), which cycles between the cell surface and TGN in an AP2-dependent manner. Wild-type BACE1 is less efficient in Aβ production than the BACE/TGN38 chimera, highlighting the relevance of the itinerary of BACE1 on APP processing. Overall the data suggests that internalised BACE1 and APP diverge at early endosomes and that Aβ biogenesis is regulated in part by the recycling itinerary of BACE1.
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Affiliation(s)
- Pei Zhi Cheryl Chia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
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91
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Tomatis VM, Papadopulos A, Malintan NT, Martin S, Wallis T, Gormal RS, Kendrick-Jones J, Buss F, Meunier FA. Myosin VI small insert isoform maintains exocytosis by tethering secretory granules to the cortical actin. ACTA ACUST UNITED AC 2013; 200:301-20. [PMID: 23382463 PMCID: PMC3563687 DOI: 10.1083/jcb.201204092] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Before undergoing neuroexocytosis, secretory granules (SGs) are mobilized and tethered to the cortical actin network by an unknown mechanism. Using an SG pull-down assay and mass spectrometry, we found that myosin VI was recruited to SGs in a Ca(2+)-dependent manner. Interfering with myosin VI function in PC12 cells reduced the density of SGs near the plasma membrane without affecting their biogenesis. Myosin VI knockdown selectively impaired a late phase of exocytosis, consistent with a replenishment defect. This exocytic defect was selectively rescued by expression of the myosin VI small insert (SI) isoform, which efficiently tethered SGs to the cortical actin network. These myosin VI SI-specific effects were prevented by deletion of a c-Src kinase phosphorylation DYD motif, identified in silico. Myosin VI SI thus recruits SGs to the cortical actin network, potentially via c-Src phosphorylation, thereby maintaining an active pool of SGs near the plasma membrane.
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Affiliation(s)
- Vanesa M Tomatis
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
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92
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Huang L, Tang Y, Xing D. Activation of nuclear estrogen receptors induced by low-power laser irradiation via PI3-K/Akt signaling cascade. J Cell Physiol 2013; 228:1045-59. [PMID: 23065720 DOI: 10.1002/jcp.24252] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 09/26/2012] [Indexed: 12/23/2022]
Abstract
Low-power laser irradiation (LPLI) has been shown to exert promotive effects on cell survival and proliferation through activation of various signaling pathways. Estrogen receptors (ERs, ERα, and ERβ) are ligand-activated transcription factors, which regulate target gene expression, promote cell proliferation, and resist apoptosis. However, it is unclear whether LPLI could induce ligand-independent activation of ERs. In the present study, we investigated the subcellular pools, nuclear redistribution, and transcriptional activity of ERs under LPLI (1.2 J/cm(2), 633 nm) treatment using single-molecule fluorescence imaging and dual-luciferase reporter assay. We found that ERs were not only localized to nucleus, but also existed in mitochondria. Moreover, we found that LPLI induced nuclear redistribution and transcriptional activity of ERs in a ligand-independent manner. Our further investigation showed that PI3-K/Akt signaling cascade was involved in LPLI-induced activation of ERs. Wortmannin, a PI3-K inhibitor, or triciribine (API-2), a specific Akt inhibitor, potently suppressed the nuclear redistribution and transcriptional activity of ERs induced by LPLI, revealing that PI3-K/Akt signaling cascade was required for the activation of ERs induced by LPLI. Collectively, we demonstrated the first time that LPLI induced the ligand-independent nuclear redistribution and transcriptional activity of ERs, which were dependent on the activity of PI3-K/Akt. Our findings provide direct evidence for the molecular mechanisms of LPLI-induced transcription factor activation.
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Affiliation(s)
- Lei Huang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, China
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93
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Koreishi M, Gniadek TJ, Yu S, Masuda J, Honjo Y, Satoh A. The golgin tether giantin regulates the secretory pathway by controlling stack organization within Golgi apparatus. PLoS One 2013; 8:e59821. [PMID: 23555793 PMCID: PMC3605407 DOI: 10.1371/journal.pone.0059821] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Accepted: 02/21/2013] [Indexed: 11/18/2022] Open
Abstract
Golgins are coiled-coil proteins that play a key role in the regulation of Golgi architecture and function. Giantin, the largest golgin in mammals, forms a complex with p115, rab1, GM130, and soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), thereby facilitating vesicle tethering and fusion processes around the Golgi apparatus. Treatment with the microtubule destabilizing drug nocodazole transforms the Golgi ribbon into individual Golgi stacks. Here we show that siRNA-mediated depletion of giantin resulted in more dispersed Golgi stacks after nocodazole treatment than by control treatment, without changing the average cisternal length. Furthermore, depletion of giantin caused an increase in cargo transport that was associated with altered cell surface protein glycosylation. Drosophila S2 cells are known to have dispersed Golgi stacks and no giantin homolog. The exogenous expression of mammalian giantin cDNA in S2 cells resulted in clustered Golgi stacks, similar to the Golgi ribbon in mammalian cells. These results suggest that the spatial organization of the Golgi ribbon is mediated by giantin, which also plays a role in cargo transport and sugar modifications.
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Affiliation(s)
- Mayuko Koreishi
- The Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Thomas J. Gniadek
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sidney Yu
- School of Biomedical Sciences and Epithelial Cell Biology Research Center, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, People’s Republic of China
| | - Junko Masuda
- Mucosal Immunity Section, Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yasuko Honjo
- The Research Core for Interdisciplinary Sciences (RCIS), Okayama University, Okayama, Japan
| | - Ayano Satoh
- The Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
- * E-mail:
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94
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Fernandes MC, Flannery AR, Andrews N, Mortara RA. Extracellular amastigotes of Trypanosoma cruzi are potent inducers of phagocytosis in mammalian cells. Cell Microbiol 2013; 15:977-91. [PMID: 23241026 PMCID: PMC3638054 DOI: 10.1111/cmi.12090] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 11/26/2012] [Accepted: 12/11/2012] [Indexed: 12/15/2022]
Abstract
The protozoan parasite Trypanosoma cruzi, the aetiological agent of Chagas' disease, has two infective life cycle stages, trypomastigotes and amastigotes. While trypomastigotes actively enter mammalian cells, highly infective extracellular amastigotes (type I T. cruzi) rely on actin-mediated uptake, which is generally inefficient in non-professional phagocytes. We found that extracellular amastigotes (EAs) of T. cruzi G strain (type I), but not Y strain (type II), were taken up 100-fold more efficiently than inert particles. Mammalian cell lines showed levels of parasite uptake comparable to macrophages, and extensive actin recruitment and polymerization was observed at the site of entry. EA uptake was not dependent on parasite-secreted molecules and required the same molecular machinery utilized by professional phagocytes during large particle phagocytosis. Transcriptional silencing of synaptotagmin VII and CD63 significantly inhibited EA internalization, demonstrating that delivery of supplemental lysosomal membrane to form the phagosome is involved in parasite uptake. Importantly, time-lapse live imaging using fluorescent reporters revealed phagosome-associated modulation of phosphoinositide metabolism during EA uptake that closely resembles what occurs during phagocytosis by macrophages. Collectively, our results demonstrate that T. cruzi EAs are potent inducers of phagocytosis in non-professional phagocytes, a process that may facilitate parasite persistence in infected hosts.
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Affiliation(s)
- Maria Cecilia Fernandes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
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95
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Stevanovic A, Thiele C. Monotopic topology is required for lipid droplet targeting of ancient ubiquitous protein 1. J Lipid Res 2012. [PMID: 23197321 DOI: 10.1194/jlr.m033852] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Ancient ubiquitous protein 1 (AUP1) is a multifunctional protein, which acts on both lipid droplets (LDs) and the endoplasmic reticulum (ER) membrane. Double localization to these two organelles, featuring very different membrane characteristics, was observed also for several other integral proteins, but little is known about the signals and mechanisms behind dual protein targeting to ER and LDs. Here we dissect the AUP1 targeting signals by analyses of localization and topology of several deletion and point mutants. We found that AUP1 is inserted into the membrane of the ER in a monotopic hairpin fashion, and subsequently transported to the hemi-membrane of LDs. A single domain localized in the N-terminal part of AUP1 enables its ER residence, the monotopic insertion, and the LD localization. Different specific residues within this multifunctional domain are responsible for achieving the complex spatial distribution pattern. A mutation of three amino acids, which changes AUP1 topology from hairpin to transmembrane, abolishes LD localization. These findings suggest that the cell is able to target a protein to multiple intracellular locations using a single domain.
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Affiliation(s)
- Ana Stevanovic
- LIMES Life and Medical Sciences Institute, University of Bonn, D-53115 Bonn, Germany
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96
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Suzuki KGN, Kasai RS, Hirosawa KM, Nemoto YL, Ishibashi M, Miwa Y, Fujiwara TK, Kusumi A. Transient GPI-anchored protein homodimers are units for raft organization and function. Nat Chem Biol 2012; 8:774-83. [DOI: 10.1038/nchembio.1028] [Citation(s) in RCA: 200] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 06/19/2012] [Indexed: 01/08/2023]
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97
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Modulating zymogen granule formation in pancreatic AR42J cells. Exp Cell Res 2012; 318:1855-66. [PMID: 22683857 DOI: 10.1016/j.yexcr.2012.05.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 05/11/2012] [Accepted: 05/24/2012] [Indexed: 01/07/2023]
Abstract
Zymogen granules (ZG) are specialized organelles in the exocrine pancreas which allow digestive enzyme storage and regulated secretion. To investigate ZG biogenesis, cargo sorting and packaging, suitable cellular model systems are required. Here, we demonstrate that granule formation in pancreatic AR42J cells, an acinar model system, can be modulated by altering the growth conditions in cell culture. We find that cultivation of AR42J cells in Panserin™ 401, a serum-free medium, enhances the induction of granule formation in the presence or absence of dexamethasone when compared to standard conditions including serum. Biochemical and morphological studies revealed an increase in ZG markers on the mRNA and protein level, as well as in granule size compared to standard conditions. Our data indicate that this effect is related to pronounced differentiation of AR42J cells. To address if enhanced expression of ZG proteins promotes granule formation, we expressed several zymogens and ZG membrane proteins in unstimulated AR42J cells and in constitutively secreting COS-7 cells. Neither single expression nor co-expression was sufficient to initiate granule formation in AR42J cells or the formation of granule-like structures in COS-7 cells as described for neuroendocrine cargo proteins. The importance of our findings for granule formation in exocrine cells is discussed.
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98
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Abstract
The polarized distribution of proteins and lipids at the surface membrane of epithelial cells results in the formation of an apical and a basolateral domain, which are separated by tight junctions. The generation and maintenance of epithelial polarity require elaborate mechanisms that guarantee correct sorting and vectorial delivery of cargo molecules. This dynamic process involves the interaction of sorting signals with sorting machineries and the formation of transport carriers. Here we review the recent advances in the field of polarized sorting in epithelial cells. We especially highlight the role of lipid rafts in apical sorting.
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99
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Mechanisms underlying the confined diffusion of cholera toxin B-subunit in intact cell membranes. PLoS One 2012; 7:e34923. [PMID: 22511973 PMCID: PMC3325267 DOI: 10.1371/journal.pone.0034923] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Accepted: 03/10/2012] [Indexed: 11/19/2022] Open
Abstract
Multivalent glycolipid binding toxins such as cholera toxin have the capacity to cluster glycolipids, a process thought to be important for their functional uptake into cells. In contrast to the highly dynamic properties of lipid probes and many lipid-anchored proteins, the B-subunit of cholera toxin (CTxB) diffuses extremely slowly when bound to its glycolipid receptor GM(1) in the plasma membrane of living cells. In the current study, we used confocal FRAP to examine the origins of this slow diffusion of the CTxB/GM(1) complex at the cell surface, relative to the behavior of a representative GPI-anchored protein, transmembrane protein, and fluorescent lipid analog. We show that the diffusion of CTxB is impeded by actin- and ATP-dependent processes, but is unaffected by caveolae. At physiological temperature, the diffusion of several cell surface markers is unchanged in the presence of CTxB, suggesting that binding of CTxB to membranes does not alter the organization of the plasma membrane in a way that influences the diffusion of other molecules. Furthermore, diffusion of the B-subunit of another glycolipid-binding toxin, Shiga toxin, is significantly faster than that of CTxB, indicating that the confined diffusion of CTxB is not a simple function of its ability to cluster glycolipids. By identifying underlying mechanisms that control CTxB dynamics at the cell surface, these findings help to delineate the fundamental properties of toxin-receptor complexes in intact cell membranes.
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100
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Toomre D. Generating live cell data using total internal reflection fluorescence microscopy. Cold Spring Harb Protoc 2012; 2012:439-46. [PMID: 22474670 DOI: 10.1101/pdb.ip068676] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Live cell fluorescent microscopy is important in elucidating dynamic cellular processes such as cell signaling, membrane trafficking, and cytoskeleton remodeling. Often, transient intermediate states are revealed only when imaged and quantitated at the single-molecule, vesicle, or organelle level. Such insight depends on the spatiotemporal resolution and sensitivity of a given microscopy method. Confocal microscopes optically section the cell and improve image contrast and axial resolution (>600 nm) compared with conventional epifluorescence microscopes. Another approach, which can selectively excite fluorophores in an even thinner optical plane (<100 nm) is total internal reflection fluorescence microscopy (TIRFM). The key principle of TIRFM is that a thin, exponentially decaying, evanescent field of excitation can be generated at the interface of two mediums of different refractive index (RI) (e.g., the glass coverslip and the biological specimen); as such, TIRFM is ill-suited to deep imaging of cells or tissue. However, for processes near the lower cell cortex, the sensitivity of TIRFM is exquisite. The recent availability of a very high numerical-aperture (NA) objective lens (>1.45) and turnkey TIRFM systems by all the major microscopy manufacturers has made TIRFM increasingly accessible and attractive to biologists, especially when performed in a quantitative manner and complemented with orthogonal genetic and molecular manipulations. This article discusses sample preparation for TIRFM, acquisition of time-lapse movies, and quantitative analysis. It also gives examples of imaging cytoskeleton dynamics and exo- and endocytosis using TIRFM.
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