151
|
Kilpatrick BS, Eden ER, Hockey LN, Yates E, Futter CE, Patel S. An Endosomal NAADP-Sensitive Two-Pore Ca 2+ Channel Regulates ER-Endosome Membrane Contact Sites to Control Growth Factor Signaling. Cell Rep 2017; 18:1636-1645. [PMID: 28199837 PMCID: PMC5318655 DOI: 10.1016/j.celrep.2017.01.052] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/16/2016] [Accepted: 01/19/2017] [Indexed: 01/25/2023] Open
Abstract
Membrane contact sites are regions of close apposition between organelles that facilitate information transfer. Here, we reveal an essential role for Ca2+ derived from the endo-lysosomal system in maintaining contact between endosomes and the endoplasmic reticulum (ER). Antagonizing action of the Ca2+-mobilizing messenger NAADP, inhibiting its target endo-lysosomal ion channel, TPC1, and buffering local Ca2+ fluxes all clustered and enlarged late endosomes/lysosomes. We show that TPC1 localizes to ER-endosome contact sites and is required for their formation. Reducing NAADP-dependent contacts delayed EGF receptor de-phosphorylation consistent with close apposition of endocytosed receptors with the ER-localized phosphatase PTP1B. In accord, downstream MAP kinase activation and mobilization of ER Ca2+ stores by EGF were exaggerated upon NAADP blockade. Membrane contact sites between endosomes and the ER thus emerge as Ca2+-dependent hubs for signaling. NAADP/TPC1 signaling maintains endo-lysosomal morphology TPC1 localizes to contacts between late endosomes and the endoplasmic reticulum NAADP/TPC1 signaling regulates contact site formation NAADP tempers EGF receptor-mediated signaling
Collapse
Affiliation(s)
- Bethan S Kilpatrick
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Emily R Eden
- Department of Cell Biology, Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Leanne N Hockey
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Elizabeth Yates
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Clare E Futter
- Department of Cell Biology, Institute of Ophthalmology, University College London, London EC1V 9EL, UK.
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK.
| |
Collapse
|
152
|
Bakker J, Spits M, Neefjes J, Berlin I. The EGFR odyssey - from activation to destruction in space and time. J Cell Sci 2017; 130:4087-4096. [PMID: 29180516 DOI: 10.1242/jcs.209197] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
When cell surface receptors engage their cognate ligands in the extracellular space, they become competent to transmit potent signals to the inside of the cell, thereby instigating growth, differentiation, motility and many other processes. In order to control these signals, activated receptors are endocytosed and thoroughly curated by the endosomal network of intracellular vesicles and proteolytic organelles. In this Review, we follow the epidermal growth factor (EGF) receptor (EGFR) from ligand engagement, through its voyage on endosomes and, ultimately, to its destruction in the lysosome. We focus on the spatial and temporal considerations underlying the molecular decisions that govern this complex journey and discuss how additional cellular organelles - particularly the ER - play active roles in the regulation of receptor lifespan. In summarizing the functions of relevant molecules on the endosomes and the ER, we cover the order of molecular events in receptor activation, trafficking and downregulation, and provide an overview of how signaling is controlled at the interface between these organelles.
Collapse
Affiliation(s)
- Jeroen Bakker
- Department of Chemical Biology, Leiden University Medical Center LUMC, Einthovenweg 22, 2333 ZC, Leiden, The Netherlands
| | - Menno Spits
- Department of Chemical Biology, Leiden University Medical Center LUMC, Einthovenweg 22, 2333 ZC, Leiden, The Netherlands
| | - Jacques Neefjes
- Department of Chemical Biology, Leiden University Medical Center LUMC, Einthovenweg 22, 2333 ZC, Leiden, The Netherlands
| | - Ilana Berlin
- Department of Chemical Biology, Leiden University Medical Center LUMC, Einthovenweg 22, 2333 ZC, Leiden, The Netherlands
| |
Collapse
|
153
|
Luarte A, Cornejo VH, Bertin F, Gallardo J, Couve A. The axonal endoplasmic reticulum: One organelle-many functions in development, maintenance, and plasticity. Dev Neurobiol 2017; 78:181-208. [PMID: 29134778 DOI: 10.1002/dneu.22560] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 11/02/2017] [Accepted: 11/07/2017] [Indexed: 12/11/2022]
Abstract
The endoplasmic reticulum (ER) is highly conserved in eukaryotes and neurons. Indeed, the localization of the organelle in axons has been known for nearly half a century. However, the relevance of the axonal ER is only beginning to emerge. In this review, we discuss the structure of the ER in axons, examining the role of ER-shaping proteins and highlighting reticulons. We analyze the multiple functions of the ER and their potential contribution to axonal physiology. First, we examine the emerging roles of the axonal ER in lipid synthesis, protein translation, processing, quality control, and secretory trafficking of transmembrane proteins. We also review the impact of the ER on calcium dynamics, focusing on intracellular mechanisms and functions. We describe the interactions between the ER and endosomes, mitochondria, and synaptic vesicles. Finally, we analyze available proteomic data of axonal preparations to reveal the dynamic functionality of the ER in axons during development. We suggest that the dynamic proteome and a validated axonal interactome, together with state-of-the-art methodologies, may provide interesting research avenues in axon physiology that may extend to pathology and regeneration. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 181-208, 2018.
Collapse
Affiliation(s)
- Alejandro Luarte
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Víctor Hugo Cornejo
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Francisca Bertin
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Javiera Gallardo
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Andrés Couve
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| |
Collapse
|
154
|
Stefan CJ, Trimble WS, Grinstein S, Drin G, Reinisch K, De Camilli P, Cohen S, Valm AM, Lippincott-Schwartz J, Levine TP, Iaea DB, Maxfield FR, Futter CE, Eden ER, Judith D, van Vliet AR, Agostinis P, Tooze SA, Sugiura A, McBride HM. Membrane dynamics and organelle biogenesis-lipid pipelines and vesicular carriers. BMC Biol 2017; 15:102. [PMID: 29089042 PMCID: PMC5663033 DOI: 10.1186/s12915-017-0432-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Discoveries spanning several decades have pointed to vital membrane lipid trafficking pathways involving both vesicular and non-vesicular carriers. But the relative contributions for distinct membrane delivery pathways in cell growth and organelle biogenesis continue to be a puzzle. This is because lipids flow from many sources and across many paths via transport vesicles, non-vesicular transfer proteins, and dynamic interactions between organelles at membrane contact sites. This forum presents our latest understanding, appreciation, and queries regarding the lipid transport mechanisms necessary to drive membrane expansion during organelle biogenesis and cell growth.
Collapse
Affiliation(s)
- Christopher J. Stefan
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT UK
| | - William S. Trimble
- Cell Biology Program, The Hospital for Sick Children and Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Sergio Grinstein
- Cell Biology Program, The Hospital for Sick Children and Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Guillaume Drin
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Karin Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 USA
| | - Pietro De Camilli
- Department of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Kavli Institute for Neuroscience and Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510 USA
| | | | | | | | - Tim P. Levine
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | - David B. Iaea
- Genentech, 1 DNA Way, South San Francisco, CA 94080 USA
| | - Frederick R. Maxfield
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065 USA
| | - Clare E. Futter
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | - Emily R. Eden
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | - Delphine Judith
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, London, UK
| | - Alexander R. van Vliet
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, London, UK
- Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Patrizia Agostinis
- Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Sharon A. Tooze
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, London, UK
| | - Ayumu Sugiura
- Kobe University Graduate School of Medicine, 1-5-6 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 Japan
| | - Heidi M. McBride
- Montreal Neurological Institute, McGill University, 3801 University Avenue, Montreal, Quebec H3A 2B4 Canada
| |
Collapse
|
155
|
Protoparvovirus Knocking at the Nuclear Door. Viruses 2017; 9:v9100286. [PMID: 28974036 PMCID: PMC5691637 DOI: 10.3390/v9100286] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 09/28/2017] [Accepted: 09/29/2017] [Indexed: 12/20/2022] Open
Abstract
Protoparvoviruses target the nucleus due to their dependence on the cellular reproduction machinery during the replication and expression of their single-stranded DNA genome. In recent years, our understanding of the multistep process of the capsid nuclear import has improved, and led to the discovery of unique viral nuclear entry strategies. Preceded by endosomal transport, endosomal escape and microtubule-mediated movement to the vicinity of the nuclear envelope, the protoparvoviruses interact with the nuclear pore complexes. The capsids are transported actively across the nuclear pore complexes using nuclear import receptors. The nuclear import is sometimes accompanied by structural changes in the nuclear envelope, and is completed by intranuclear disassembly of capsids and chromatinization of the viral genome. This review discusses the nuclear import strategies of protoparvoviruses and describes its dynamics comprising active and passive movement, and directed and diffusive motion of capsids in the molecularly crowded environment of the cell.
Collapse
|
156
|
The Role of Mitochondria in the Activation/Maintenance of SOCE: Membrane Contact Sites as Signaling Hubs Sustaining Store-Operated Ca2+ Entry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:277-296. [DOI: 10.1007/978-3-319-57732-6_15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
|
157
|
Chakrabarty Y, Bhattacharyya SN. Leishmania donovani restricts mitochondrial dynamics to enhance miRNP stability and target RNA repression in host macrophages. Mol Biol Cell 2017; 28:2091-2105. [PMID: 28539410 PMCID: PMC5509422 DOI: 10.1091/mbc.e16-06-0388] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 05/08/2017] [Accepted: 05/16/2017] [Indexed: 12/14/2022] Open
Abstract
MicroRNAs (miRNAs), the tiny regulatory RNAs, form complexes with Argonaute (Ago) proteins and inhibit gene expression in metazoan cells. While studying parasite-invaded macrophages, we identify a unique mode of gene regulation in which the parasite Leishmania donovani (Ld) causes mitochondrial depolarization, reduces mitochondrial dynamics, and restricts turnover of cellular microRNA ribonucleoprotein (miRNP) complexes in infected host cells. This leads to increased stability of miRNPs along with elevated levels of Ago2-bound cytokine mRNA in Ld-infected macrophages. Thus the increase of miRNP stability in Ld-infected cells curtails production of proinflammatory cytokines, which are otherwise detrimental for survival of the parasite within the infected macrophages. Loss of mitochondrial membrane potential is accompanied by reduced juxtaposition of endoplasmic reticulum (ER) and mitochondria as well as endosomes. This is likely coupled with enhanced sequestration and stabilization of ER- associated miRNPs observed in infected macrophage cells. Mitofusin 2 (Mfn2), a membrane protein implicated in ER-mitochondria tethering, also shows reduced expression in Ld-infected cells. A mitochondrial role in Ld-induced alteration of miRNA activity and stability is further corroborated by impaired compartmentalization and stabilization of miRNP components in Mfn2-depleted mammalian cells.
Collapse
Affiliation(s)
- Yogaditya Chakrabarty
- RNA Biology Research Laboratories, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Suvendra N Bhattacharyya
- RNA Biology Research Laboratories, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| |
Collapse
|
158
|
Eisenberg-Bord M, Shai N, Schuldiner M, Bohnert M. A Tether Is a Tether Is a Tether: Tethering at Membrane Contact Sites. Dev Cell 2017; 39:395-409. [PMID: 27875684 DOI: 10.1016/j.devcel.2016.10.022] [Citation(s) in RCA: 263] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 10/19/2016] [Accepted: 10/26/2016] [Indexed: 01/08/2023]
Abstract
Membrane contact sites enable interorganelle communication by positioning organelles in close proximity using molecular "tethers." With a growing understanding of the importance of contact sites, the hunt for new contact sites and their tethers is in full swing. Determining just what is a tether has proven challenging. Here, we aim to delineate guidelines that define the prerequisites for categorizing a protein as a tether. Setting this gold standard now, while groups from different disciplines are beginning to explore membrane contact sites, will enable efficient cooperation in the growing field and help to realize a great collaborative opportunity to boost its development.
Collapse
Affiliation(s)
- Michal Eisenberg-Bord
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Nadav Shai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Maria Bohnert
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel.
| |
Collapse
|
159
|
Eden ER, Sanchez-Heras E, Tsapara A, Sobota A, Levine TP, Futter CE. Annexin A1 Tethers Membrane Contact Sites that Mediate ER to Endosome Cholesterol Transport. Dev Cell 2017; 37:473-83. [PMID: 27270042 PMCID: PMC4906250 DOI: 10.1016/j.devcel.2016.05.005] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 04/11/2016] [Accepted: 05/09/2016] [Indexed: 11/27/2022]
Abstract
Membrane contact sites between the ER and multivesicular endosomes/bodies (MVBs) play important roles in endosome positioning and fission and in neurite outgrowth. ER-MVB contacts additionally function in epidermal growth factor receptor (EGFR) tyrosine kinase downregulation by providing sites where the ER-localized phosphatase, PTP1B, interacts with endocytosed EGFR before the receptor is sorted onto intraluminal vesicles (ILVs). Here we show that these contacts are tethered by annexin A1 and its Ca(2+)-dependent ligand, S100A11, and form a subpopulation of differentially regulated contact sites between the ER and endocytic organelles. Annexin A1-regulated contacts function in the transfer of ER-derived cholesterol to the MVB when low-density lipoprotein-cholesterol in endosomes is low. This sterol traffic depends on interaction between ER-localized VAP and endosomal oxysterol-binding protein ORP1L, and is required for the formation of ILVs within the MVB and thus for the spatial regulation of EGFR signaling.
Collapse
Affiliation(s)
- Emily R Eden
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | | | - Anna Tsapara
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; Technical University of Crete, 73100 Chania, Greece
| | - Andrzej Sobota
- Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Tim P Levine
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | | |
Collapse
|
160
|
Contacts between the endoplasmic reticulum and other membranes in neurons. Proc Natl Acad Sci U S A 2017; 114:E4859-E4867. [PMID: 28559323 DOI: 10.1073/pnas.1701078114] [Citation(s) in RCA: 314] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Close appositions between the membrane of the endoplasmic reticulum (ER) and other intracellular membranes have important functions in cell physiology. These include lipid homeostasis, regulation of Ca2+ dynamics, and control of organelle biogenesis and dynamics. Although these membrane contacts have previously been observed in neurons, their distribution and abundance have not been systematically analyzed. Here, we have used focused ion beam-scanning electron microscopy to generate 3D reconstructions of intracellular organelles and their membrane appositions involving the ER (distance ≤30 nm) in different neuronal compartments. ER-plasma membrane (PM) contacts were particularly abundant in cell bodies, with large, flat ER cisternae apposed to the PM, sometimes with a notably narrow lumen (thin ER). Smaller ER-PM contacts occurred throughout dendrites, axons, and in axon terminals. ER contacts with mitochondria were abundant in all compartments, with the ER often forming a network that embraced mitochondria. Small focal contacts were also observed with tubulovesicular structures, likely to be endosomes, and with sparse multivesicular bodies and lysosomes found in our reconstructions. Our study provides an anatomical reference for interpreting information about interorganelle communication in neurons emerging from functional and biochemical studies.
Collapse
|
161
|
Applying systems-level spectral imaging and analysis to reveal the organelle interactome. Nature 2017; 546:162-167. [PMID: 28538724 PMCID: PMC5536967 DOI: 10.1038/nature22369] [Citation(s) in RCA: 661] [Impact Index Per Article: 94.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 04/13/2017] [Indexed: 12/14/2022]
Abstract
The organization of the eukaryotic cell into discrete membrane-bound organelles allows for the separation of incompatible biochemical processes, but the activities of these organelles must be coordinated. For example, lipid metabolism is distributed between the endoplasmic reticulum for lipid synthesis, lipid droplets for storage and transport, mitochondria and peroxisomes for β-oxidation, and lysosomes for lipid hydrolysis and recycling. It is increasingly recognized that organelle contacts have a vital role in diverse cellular functions. However, the spatial and temporal organization of organelles within the cell remains poorly characterized, as fluorescence imaging approaches are limited in the number of different labels that can be distinguished in a single image. Here we present a systems-level analysis of the organelle interactome using a multispectral image acquisition method that overcomes the challenge of spectral overlap in the fluorescent protein palette. We used confocal and lattice light sheet instrumentation and an imaging informatics pipeline of five steps to achieve mapping of organelle numbers, volumes, speeds, positions and dynamic inter-organelle contacts in live cells from a monkey fibroblast cell line. We describe the frequency and locality of two-, three-, four- and five-way interactions among six different membrane-bound organelles (endoplasmic reticulum, Golgi, lysosome, peroxisome, mitochondria and lipid droplet) and show how these relationships change over time. We demonstrate that each organelle has a characteristic distribution and dispersion pattern in three-dimensional space and that there is a reproducible pattern of contacts among the six organelles, that is affected by microtubule and cell nutrient status. These live-cell confocal and lattice light sheet spectral imaging approaches are applicable to any cell system expressing multiple fluorescent probes, whether in normal conditions or when cells are exposed to disturbances such as drugs, pathogens or stress. This methodology thus offers a powerful descriptive tool and can be used to develop hypotheses about cellular organization and dynamics.
Collapse
|
162
|
Heusermann W, Hean J, Trojer D, Steib E, von Bueren S, Graff-Meyer A, Genoud C, Martin K, Pizzato N, Voshol J, Morrissey DV, Andaloussi SEL, Wood MJ, Meisner-Kober NC. Exosomes surf on filopodia to enter cells at endocytic hot spots, traffic within endosomes, and are targeted to the ER. J Cell Biol 2017; 213:173-84. [PMID: 27114500 PMCID: PMC5084269 DOI: 10.1083/jcb.201506084] [Citation(s) in RCA: 308] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 03/09/2016] [Indexed: 12/19/2022] Open
Abstract
Exosomes are nanovesicles released by virtually all cells, which act as intercellular messengers by transfer of protein, lipid, and RNA cargo. Their quantitative efficiency, routes of cell uptake, and subcellular fate within recipient cells remain elusive. We quantitatively characterize exosome cell uptake, which saturates with dose and time and reaches near 100% transduction efficiency at picomolar concentrations. Highly reminiscent of pathogenic bacteria and viruses, exosomes are recruited as single vesicles to the cell body by surfing on filopodia as well as filopodia grabbing and pulling motions to reach endocytic hot spots at the filopodial base. After internalization, exosomes shuttle within endocytic vesicles to scan the endoplasmic reticulum before being sorted into the lysosome as their final intracellular destination. Our data quantify and explain the efficiency of exosome internalization by recipient cells, establish a new parallel between exosome and virus host cell interaction, and suggest unanticipated routes of subcellular cargo delivery.
Collapse
Affiliation(s)
- Wolf Heusermann
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Justin Hean
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, England, UK
| | - Dominic Trojer
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Emmanuelle Steib
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Stefan von Bueren
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | | | - Christel Genoud
- Friedrich-Miescher Institute for Biomedical Research, CH-4000 Basel, Switzerland
| | - Katrin Martin
- Department of Biomedicine, University of Basel, CH-4058 Basel, Switzerland
| | - Nicolas Pizzato
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Johannes Voshol
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | | | - Samir E L Andaloussi
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, England, UK Department of Laboratory Medicine, Karolinska Institutet, SE-141 86 Huddinge, Sweden
| | - Matthew J Wood
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, England, UK
| | | |
Collapse
|
163
|
Nunes-Hasler P, Demaurex N. The ER phagosome connection in the era of membrane contact sites. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1513-1524. [PMID: 28432021 DOI: 10.1016/j.bbamcr.2017.04.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 04/06/2017] [Accepted: 04/13/2017] [Indexed: 12/19/2022]
Abstract
Phagocytosis is an essential mechanism through which innate immune cells ingest foreign material that is either destroyed or used to generate and present antigens and initiate adaptive immune responses. While a role for the ER during phagosome biogenesis has been recognized, whether fusion with ER cisternae or vesicular derivatives occurs has been the source of much contention. Membrane contact sites (MCS) are tight appositions between ER membranes and various organelles that coordinate multiple functions including localized signalling, lipid transfer and trafficking. The discovery that MCS form between the ER and phagosomes now begs the question of whether MCS play a role in connecting the ER to phagosomes under different contexts. In this review, we consider the implications of MCS between the ER and phagosomes during cross-presentation and infection with intracellular pathogens. We also discuss the similarities between these contacts and those between the ER and plasma membrane and acidic organelles such as endosomes and lysosomes. This article is part of a Special Issue entitled: Membrane Contact Sites edited by Christian Ungermann and Benoit Kornmann.
Collapse
Affiliation(s)
- Paula Nunes-Hasler
- Department of Cell Physiology and Metabolism, University of Geneva, Switzerland.
| | - Nicolas Demaurex
- Department of Cell Physiology and Metabolism, University of Geneva, Switzerland
| |
Collapse
|
164
|
Allison R, Edgar JR, Pearson G, Rizo T, Newton T, Günther S, Berner F, Hague J, Connell JW, Winkler J, Lippincott-Schwartz J, Beetz C, Winner B, Reid E. Defects in ER-endosome contacts impact lysosome function in hereditary spastic paraplegia. J Cell Biol 2017; 216:1337-1355. [PMID: 28389476 PMCID: PMC5412567 DOI: 10.1083/jcb.201609033] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 01/20/2017] [Accepted: 02/21/2017] [Indexed: 01/29/2023] Open
Abstract
Hereditary spastic paraplegia (HSP) is a genetically heterogeneous disease caused by mutations in many genes, including those encoding spastin, strumpellin, or REEP1. Allison et al. show that similar lysosomal phenotypes are associated with mutations in different classes of HSP proteins and suggest that defective ER–endosome contacts and endosome tubule fission may be a common cause of axon degeneration in the disease. Contacts between endosomes and the endoplasmic reticulum (ER) promote endosomal tubule fission, but the mechanisms involved and consequences of tubule fission failure are incompletely understood. We found that interaction between the microtubule-severing enzyme spastin and the ESCRT protein IST1 at ER–endosome contacts drives endosomal tubule fission. Failure of fission caused defective sorting of mannose 6-phosphate receptor, with consequently disrupted lysosomal enzyme trafficking and abnormal lysosomal morphology, including in mouse primary neurons and human stem cell–derived neurons. Consistent with a role for ER-mediated endosomal tubule fission in lysosome function, similar lysosomal abnormalities were seen in cellular models lacking the WASH complex component strumpellin or the ER morphogen REEP1. Mutations in spastin, strumpellin, or REEP1 cause hereditary spastic paraplegia (HSP), a disease characterized by axonal degeneration. Our results implicate failure of the ER–endosome contact process in axonopathy and suggest that coupling of ER-mediated endosomal tubule fission to lysosome function links different classes of HSP proteins, previously considered functionally distinct, into a unifying pathway for axonal degeneration.
Collapse
Affiliation(s)
- Rachel Allison
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - James R Edgar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Clinical Biochemistry, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Guy Pearson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Tania Rizo
- Interdisciplinary Center for Clinical Research (IZKF) Junior Research Group III and Federal Ministry of Education and Research (BMBF) Research Group Neuroscience, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany
| | - Timothy Newton
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Sven Günther
- Department of Clinical Chemistry and Laboratory Diagnostics, Jena University Hospital, 07743 Jena, Germany
| | - Fiamma Berner
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Jennifer Hague
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - James W Connell
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Jürgen Winkler
- Department of Molecular Neurology, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany
| | | | - Christian Beetz
- Department of Clinical Chemistry and Laboratory Diagnostics, Jena University Hospital, 07743 Jena, Germany
| | - Beate Winner
- Interdisciplinary Center for Clinical Research (IZKF) Junior Research Group III and Federal Ministry of Education and Research (BMBF) Research Group Neuroscience, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany.,Institute of Human Genetics, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany
| | - Evan Reid
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK .,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
| |
Collapse
|
165
|
Wilhelm LP, Wendling C, Védie B, Kobayashi T, Chenard MP, Tomasetto C, Drin G, Alpy F. STARD3 mediates endoplasmic reticulum-to-endosome cholesterol transport at membrane contact sites. EMBO J 2017; 36:1412-1433. [PMID: 28377464 PMCID: PMC5430228 DOI: 10.15252/embj.201695917] [Citation(s) in RCA: 161] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 03/03/2017] [Accepted: 03/06/2017] [Indexed: 01/04/2023] Open
Abstract
StAR‐related lipid transfer domain‐3 (STARD3) is a sterol‐binding protein that creates endoplasmic reticulum (ER)–endosome contact sites. How this protein, at the crossroad between sterol uptake and synthesis pathways, impacts the intracellular distribution of this lipid was ill‐defined. Here, by using in situ cholesterol labeling and quantification, we demonstrated that STARD3 induces cholesterol accumulation in endosomes at the expense of the plasma membrane. STARD3‐mediated cholesterol routing depends both on its lipid transfer activity and its ability to create ER–endosome contacts. Corroborating this, in vitro reconstitution assays indicated that STARD3 and its ER‐anchored partner, Vesicle‐associated membrane protein‐associated protein (VAP), assemble into a machine that allows a highly efficient transport of cholesterol within membrane contacts. Thus, STARD3 is a cholesterol transporter scaffolding ER–endosome contacts and modulating cellular cholesterol repartition by delivering cholesterol to endosomes.
Collapse
Affiliation(s)
- Léa P Wilhelm
- Functional Genomics and Cancer Department, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U 964, Illkirch, France.,Centre National de la Recherche Scientifique (CNRS), UMR 7104, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Corinne Wendling
- Functional Genomics and Cancer Department, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U 964, Illkirch, France.,Centre National de la Recherche Scientifique (CNRS), UMR 7104, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Benoît Védie
- AP-HP (Assistance Publique - Hôpitaux de Paris), Hôpital Européen Georges Pompidou, Service de Biochimie, Paris, France
| | - Toshihide Kobayashi
- Université de Strasbourg, Illkirch, France.,Laboratory of Biophotonics and Pharmacology, Centre National de la Recherche Scientifique (CNRS), UMR 7213, Illkirch, France
| | - Marie-Pierre Chenard
- Functional Genomics and Cancer Department, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Service d'Anatomie Pathologique Générale, Centre Hospitalier Universitaire de Hautepierre, Strasbourg, France
| | - Catherine Tomasetto
- Functional Genomics and Cancer Department, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France .,Institut National de la Santé et de la Recherche Médicale (INSERM), U 964, Illkirch, France.,Centre National de la Recherche Scientifique (CNRS), UMR 7104, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Guillaume Drin
- Université Côte d'Azur, CNRS Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Fabien Alpy
- Functional Genomics and Cancer Department, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France .,Institut National de la Santé et de la Recherche Médicale (INSERM), U 964, Illkirch, France.,Centre National de la Recherche Scientifique (CNRS), UMR 7104, Illkirch, France.,Université de Strasbourg, Illkirch, France
| |
Collapse
|
166
|
Neefjes J, Jongsma MML, Berlin I. Stop or Go? Endosome Positioning in the Establishment of Compartment Architecture, Dynamics, and Function. Trends Cell Biol 2017; 27:580-594. [PMID: 28363667 DOI: 10.1016/j.tcb.2017.03.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/03/2017] [Accepted: 03/06/2017] [Indexed: 02/03/2023]
Abstract
The endosomal system constitutes a key negotiator between the environment of a cell and its internal affairs. Comprised of a complex membranous network, wherein each vesicle can in principle move autonomously throughout the cell, the endosomal system operates as a coherent unit to optimally face external challenges and maintain homeostasis. Our appreciation of how individual endosomes are controlled in time and space to best serve their collective purpose has evolved dramatically in recent years. In light of these efforts, the endoplasmic reticulum (ER) - with its expanse of membranes permeating the cytoplasmic space - has emerged as a potent spatiotemporal organizer of endosome biology. We review the latest advances in our understanding of the mechanisms underpinning endosomal transport and positioning, with emphasis on the contributions from the ER, and offer a perspective on how the interplay between these aspects shapes the architecture and dynamics of the endosomal system and drives its myriad cellular functions.
Collapse
Affiliation(s)
- Jacques Neefjes
- Department of Chemical Immunology, Leiden University Medical Center (LUMC), Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Marlieke M L Jongsma
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center (AMC)/Universiteit van Amsterdam (UvA), Plesmanlaan 125, 1066 CX Amsterdam, The Netherlands
| | - Ilana Berlin
- Department of Chemical Immunology, Leiden University Medical Center (LUMC), Einthovenweg 20, 2333 ZC Leiden, The Netherlands.
| |
Collapse
|
167
|
Bäck N, Kanerva K, Kurutihalli V, Yanik A, Ikonen E, Mains RE, Eipper BA. The endocytic pathways of a secretory granule membrane protein in HEK293 cells: PAM and EGF traverse a dynamic multivesicular body network together. Eur J Cell Biol 2017; 96:407-417. [PMID: 28377049 DOI: 10.1016/j.ejcb.2017.03.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/22/2017] [Accepted: 03/22/2017] [Indexed: 12/31/2022] Open
Abstract
Peptidylglycine α-amidating monooxygenase (PAM) is highly expressed in neurons and endocrine cells, where it catalyzes one of the final steps in the biosynthesis of bioactive peptides. PAM is also expressed in unicellular organisms such as Chlamydomonas reinhardtii, which do not store peptides in secretory granules. As for other granule membrane proteins, PAM is retrieved from the cell surface and returned to the trans-Golgi network. This pathway involves regulated entry of PAM into multivesicular body intralumenal vesicles (ILVs). The aim of this study was defining the endocytic pathways utilized by PAM in cells that do not store secretory products in granules. Using stably transfected HEK293 cells, endocytic trafficking of PAM was compared to that of the mannose 6-phosphate (MPR) and EGF (EGFR) receptors, established markers for the endosome to trans-Golgi network and degradative pathways, respectively. As in neuroendocrine cells, PAM internalized by HEK293 cells accumulated in the trans-Golgi network. Based on surface biotinylation, >70% of the PAM on the cell surface was recovered intact after a 4h chase and soluble, bifunctional PAM was produced. Endosomes containing PAM generally contained both EGFR and MPR and ultrastructural analysis confirmed that all three cargos accumulated in ILVs. PAM containing multivesicular bodies made frequent dynamic tubular contacts with younger and older multivesicular bodies. Frequent dynamic contacts were observed between lysosomes and PAM containing early endosomes and multivesicular bodies. The ancient ability of PAM to localize to ciliary membranes, which release bioactive ectosomes, may be related to its ability to accumulate in ILVs and exosomes.
Collapse
Affiliation(s)
- Nils Bäck
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
| | - Kristiina Kanerva
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | | | - Andrew Yanik
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
| | - Elina Ikonen
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
| | - Betty A Eipper
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
| |
Collapse
|
168
|
Luo J, Jiang L, Yang H, Song BL. Routes and mechanisms of post-endosomal cholesterol trafficking: A story that never ends. Traffic 2017; 18:209-217. [DOI: 10.1111/tra.12471] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/08/2017] [Accepted: 02/08/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Jie Luo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; Wuhan University; Wuhan China
| | - Luyi Jiang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; Wuhan University; Wuhan China
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences; The University of New South Wales; Sydney Australia
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; Wuhan University; Wuhan China
| |
Collapse
|
169
|
Atlastin regulates store-operated calcium entry for nerve growth factor-induced neurite outgrowth. Sci Rep 2017; 7:43490. [PMID: 28240257 PMCID: PMC5327485 DOI: 10.1038/srep43490] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/24/2017] [Indexed: 11/20/2022] Open
Abstract
Homotypic membrane fusion of the endoplasmic reticulum (ER) is mediated by a class of dynamin-like GTPases known as atlastin (ATL). Depletion of or mutations in ATL cause an unbranched ER morphology and hereditary spastic paraplegia (HSP), a neurodegenerative disease characterized by axon shortening in corticospinal motor neurons and progressive spasticity of the lower limbs. How ER shaping is linked to neuronal defects is poorly understood. Here, we show that dominant-negative mutants of ATL1 in PC-12 cells inhibit nerve growth factor (NGF)-induced neurite outgrowth. Overexpression of wild-type or mutant ATL1 or depletion of ATLs alters ER morphology and affects store-operated calcium entry (SOCE) by decreasing STIM1 puncta formation near the plasma membrane upon calcium depletion of the ER. In addition, blockage of the STIM1-Orai pathway effectively abolishes neurite outgrowth of PC-12 cells stimulated by NGF. These results suggest that SOCE plays an important role in neuronal regeneration, and mutations in ATL1 may cause HSP, partly by undermining SOCE.
Collapse
|
170
|
Griffing LR, Lin C, Perico C, White RR, Sparkes I. Plant ER geometry and dynamics: biophysical and cytoskeletal control during growth and biotic response. PROTOPLASMA 2017; 254:43-56. [PMID: 26862751 PMCID: PMC5216105 DOI: 10.1007/s00709-016-0945-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 01/13/2016] [Indexed: 05/20/2023]
Abstract
The endoplasmic reticulum (ER) is an intricate and dynamic network of membrane tubules and cisternae. In plant cells, the ER 'web' pervades the cortex and endoplasm and is continuous with adjacent cells as it passes through plasmodesmata. It is therefore the largest membranous organelle in plant cells. It performs essential functions including protein and lipid synthesis, and its morphology and movement are linked to cellular function. An emerging trend is that organelles can no longer be seen as discrete membrane-bound compartments, since they can physically interact and 'communicate' with one another. The ER may form a connecting central role in this process. This review tackles our current understanding and quantification of ER dynamics and how these change under a variety of biotic and developmental cues.
Collapse
Affiliation(s)
- Lawrence R Griffing
- Biology Department, Texas A&M University, 3258 TAMU, College Station, TX, 77843, USA
| | - Congping Lin
- Mathematics Research Institute, Harrison Building, University of Exeter, Exeter, EX4 4QF, UK
| | - Chiara Perico
- Biosciences, CLES, Exeter University, Geoffrey Pope Building, Stocker Rd, Exeter, EX4 4QD, UK
| | - Rhiannon R White
- Biosciences, CLES, Exeter University, Geoffrey Pope Building, Stocker Rd, Exeter, EX4 4QD, UK
| | - Imogen Sparkes
- Biosciences, CLES, Exeter University, Geoffrey Pope Building, Stocker Rd, Exeter, EX4 4QD, UK.
| |
Collapse
|
171
|
Henne WM. Discovery and Roles of ER-Endolysosomal Contact Sites in Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:135-147. [PMID: 28815527 DOI: 10.1007/978-981-10-4567-7_10] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Inter-organelle membrane contact sites (MCSs) serve as unique microenvironments for the sensing and exchange of cellular metabolites and lipids. Though poorly defined, ER-endolysosomal contact sites are quickly becoming recognized as centers for inter-organelle lipid exchange and metabolic decision-making. Here, we review the discovery and current state of knowledge of ER-endolysosomal MCSs with particular focus on the molecular players that establish and/or utilize these contact sites in metabolism. We also discuss associations of ER-endolysosomal MCS-associated proteins in human disease, as well as the therapeutic promise these contact sites hold in modulating cellular physiology.
Collapse
Affiliation(s)
- William Mike Henne
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, 75013, USA.
| |
Collapse
|
172
|
Yuan H, Sehgal PB. MxA Is a Novel Regulator of Endosome-Associated Transcriptional Signaling by Bone Morphogenetic Proteins 4 and 9 (BMP4 and BMP9). PLoS One 2016; 11:e0166382. [PMID: 27875556 PMCID: PMC5119740 DOI: 10.1371/journal.pone.0166382] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/27/2016] [Indexed: 01/02/2023] Open
Abstract
There is confusion about the role that IFN-α plays in the pathogenesis of pulmonary arterial hypertension (PAH) with different investigators reporting a causative or a protective role. There is now clear evidence in PAH pathogenesis for the involvement of BMP4 and BMP9 signaling, and its disruption by mutations in BMPR2. In the present study, we investigated MxA, an IFN-α-inducible cytoplasmic dynamin-family GTPase for effects on BMP4/9 signaling, including in the presence of PAH-disease-associated mutants of BMPR2. In human pulmonary arterial endothelial cells (HPAECs), IFN-α-induced endogenous as well as exogenously expressed MxA was associated with endosomes that aligned alongside microtubules and tubules of the endoplasmic reticulum (ER). Moreover, IFN-α and MxA stimulated basal and BMP4/9 signaling to a Smad1/5/8-responsive pBRE-Luc reporter. In HEK293T cells, immunoelectron microscopy confirmed the association of MxA with endosomes, and immunofluorescence methods showed these to be positive for early endosome markers (early endosomal antigen 1, clathrin light chain and Rab5) and RSmad1/5/8. Functionally, using different genetic and inhibitor approaches, we observed that clathrin-mediated endocytosis enhanced and caveolin-mediated endocytosis inhibited the transcriptional response to BMP4 and BMP9. MxA produced a further 3-4-fold enhancement of the BMP-induced response in a clathrin-endocytosis dependent manner. The microtubule inhibitor nocodazole and stabilizer paclitaxel respectively attenuated and enhanced the effect of MxA, implicating microtubule integrity in this process. MxA enhanced BMP-induced signaling in the presence of wild-type BMPR2, and partially rescued signaling from some PAH-disease-associated BMPR2 mutants. Taken together, the data identify MxA as a novel stimulator of BMP4 and BMP9 transcriptional signaling, and suggest it to be a candidate IFN-α-inducible mechanism that might have a protective role against development of PAH and other vascular diseases.
Collapse
Affiliation(s)
- Huijuan Yuan
- Department of. Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States of America
| | - Pravin B. Sehgal
- Department of. Cell Biology & Anatomy, and Department of Medicine, New York Medical College, Valhalla, New York, United States of America
- * E-mail:
| |
Collapse
|
173
|
Kanemoto S, Nitani R, Murakami T, Kaneko M, Asada R, Matsuhisa K, Saito A, Imaizumi K. Multivesicular body formation enhancement and exosome release during endoplasmic reticulum stress. Biochem Biophys Res Commun 2016; 480:166-172. [PMID: 27725157 DOI: 10.1016/j.bbrc.2016.10.019] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 10/07/2016] [Indexed: 11/19/2022]
Abstract
The endoplasmic reticulum (ER) plays a pivotal role in maintaining cellular homeostasis. However, numerous environmental and genetic factors give rise to ER stress by inducing an accumulation of unfolded proteins. Under ER stress conditions, cells initiate the unfolded protein response (UPR). Here, we demonstrate a novel aspect of the UPR by electron microscopy and immunostaining analyses, whereby multivesicular body (MVB) formation was enhanced after ER stress. This MVB formation was influenced by inhibition of ER stress transducers inositol required enzyme 1 (IRE1) and PKR-like ER kinase (PERK). Furthermore, exosome release was also increased during ER stress. However, in IRE1 or PERK deficient cells, exosome release was not upregulated, indicating that IRE1- and PERK-mediated pathways are involved in ER stress-dependent exosome release.
Collapse
Affiliation(s)
- Soshi Kanemoto
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan.
| | - Ryota Nitani
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Tatsuhiko Murakami
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Masayuki Kaneko
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Rie Asada
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Koji Matsuhisa
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Atsushi Saito
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Kazunori Imaizumi
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan.
| |
Collapse
|
174
|
Tan X, Thapa N, Liao Y, Choi S, Anderson RA. PtdIns(4,5)P2 signaling regulates ATG14 and autophagy. Proc Natl Acad Sci U S A 2016; 113:10896-901. [PMID: 27621469 PMCID: PMC5047215 DOI: 10.1073/pnas.1523145113] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Autophagy is a regulated self-digestion pathway with fundamental roles in cell homeostasis and diseases. Autophagy is regulated by coordinated actions of a series of autophagy-related (ATG) proteins. The Barkor/ATG14(L)-VPS34 (a class III phosphatidylinositol 3-kinase) complex and its product phosphatidylinositol 3-phosphate [PtdIns(3)P] play key roles in autophagy initiation. ATG14 contains a C-terminal Barkor/ATG14(L) autophagosome-targeting sequence (BATS) domain that senses the curvature of PtdIns(3)P-containing membrane. The BATS domain also strongly binds PtdIns(4,5)P2, but the functional significance has been unclear. Here we show that ATG14 specifically interacts with type Iγ PIP kinase isoform 5 (PIPKIγi5), an enzyme that generates PtdIns(4,5)P2 in mammalian cells. Autophagosomes have associated PIPKIγi5 and PtdIns(4,5)P2 that are colocalized with late endosomes and the endoplasmic reticulum. PtdIns(4,5)P2 generation at these sites requires PIPKIγi5. Loss of PIPKIγi5 results in a loss of ATG14, UV irradiation resistance-associated gene, and Beclin 1 and a block of autophagy. PtdIns(4,5)P2 binding to the ATG14-BATS domain regulates ATG14 interaction with VPS34 and Beclin 1, and thus plays a key role in ATG14 complex assembly and autophagy initiation. This study identifies an unexpected role for PtdIns(4,5)P2 signaling in the regulation of ATG14 complex and autophagy.
Collapse
Affiliation(s)
- Xiaojun Tan
- Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706
| | - Narendra Thapa
- Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706
| | - Yihan Liao
- Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706
| | - Suyong Choi
- Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706
| | - Richard A Anderson
- Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706
| |
Collapse
|
175
|
Salogiannis J, Reck-Peterson SL. Hitchhiking: A Non-Canonical Mode of Microtubule-Based Transport. Trends Cell Biol 2016; 27:141-150. [PMID: 27665063 DOI: 10.1016/j.tcb.2016.09.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/29/2016] [Accepted: 09/02/2016] [Indexed: 01/01/2023]
Abstract
The long-range movement of organelles, vesicles, and macromolecular complexes by microtubule-based transport is crucial for cell growth and survival. The canonical view of intracellular transport is that each cargo directly recruits molecular motors via cargo-specific adaptor molecules. Recently, a new paradigm called 'hitchhiking' has emerged: some cargos can achieve motility by interacting with other cargos that have already recruited molecular motors. In this way, cargos are co-transported together and their movements are directly coupled. Cargo hitchhiking was discovered in fungi. However, the observation that organelle dynamics are coupled in mammalian cells suggests that this paradigm may be evolutionarily conserved. We review here the data for hitchhiking and discuss the biological significance of this non-canonical mode of microtubule-based transport.
Collapse
Affiliation(s)
- John Salogiannis
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA; Section of Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Samara L Reck-Peterson
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA; Section of Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
176
|
Das A, Nag S, Mason AB, Barroso MM. Endosome-mitochondria interactions are modulated by iron release from transferrin. J Cell Biol 2016; 214:831-45. [PMID: 27646275 PMCID: PMC5037410 DOI: 10.1083/jcb.201602069] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 08/11/2016] [Indexed: 12/21/2022] Open
Abstract
Using superresolution and quantitative fluorescence microscopy, Das et al. have revealed that iron-transferrin–containing endosomes directly interact with mitochondria, facilitating iron transfer in epithelial cells. Their findings further enrich the repertoire of organelle–organelle direct interactions to accomplish a functional significance. Transient “kiss and run” interactions between endosomes containing iron-bound transferrin (Tf) and mitochondria have been shown to facilitate direct iron transfer in erythroid cells. In this study, we used superresolution three-dimensional (3D) direct stochastic optical reconstruction microscopy to show that Tf-containing endosomes directly interact with mitochondria in epithelial cells. We used live-cell time-lapse fluorescence microscopy, followed by 3D rendering, object tracking, and a distance transformation algorithm, to track Tf-endosomes and characterize the dynamics of their interactions with mitochondria. Quenching of iron sensor RDA-labeled mitochondria confirmed functional iron transfer by an interacting Tf-endosome. The motility of Tf-endosomes is significantly reduced upon interaction with mitochondria. To further assess the functional role of iron in the ability of Tf-endosomes to interact with mitochondria, we blocked endosomal iron release by using a Tf K206E/K534A mutant. Blocking intraendosomal iron release led to significantly increased motility of Tf-endosomes and increased duration of endosome–mitochondria interactions. Thus, intraendosomal iron regulates the kinetics of the interactions between Tf-containing endosomes and mitochondria in epithelial cells.
Collapse
Affiliation(s)
- Anupam Das
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208
| | - Sagarika Nag
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208
| | - Anne B Mason
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, VT 05405
| | - Margarida M Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208
| |
Collapse
|
177
|
Sharoar MG, Shi Q, Ge Y, He W, Hu X, Perry G, Zhu X, Yan R. Dysfunctional tubular endoplasmic reticulum constitutes a pathological feature of Alzheimer's disease. Mol Psychiatry 2016; 21:1263-71. [PMID: 26619807 PMCID: PMC4887420 DOI: 10.1038/mp.2015.181] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/11/2015] [Accepted: 09/24/2015] [Indexed: 12/27/2022]
Abstract
Pathological features in Alzheimer's brains include mitochondrial dysfunction and dystrophic neurites (DNs) in areas surrounding amyloid plaques. Using a mouse model that overexpresses reticulon 3 (RTN3) and spontaneously develops age-dependent hippocampal DNs, here we report that DNs contain both RTN3 and REEPs, topologically similar proteins that can shape tubular endoplasmic reticulum (ER). Importantly, ultrastructural examinations of such DNs revealed gradual accumulation of tubular ER in axonal termini, and such abnormal tubular ER inclusion is found in areas surrounding amyloid plaques in biopsy samples from Alzheimer's disease (AD) brains. Functionally, abnormally clustered tubular ER induces enhanced mitochondrial fission in the early stages of DN formation and eventual mitochondrial degeneration at later stages. Furthermore, such DNs are abrogated when RTN3 is ablated in aging and AD mouse models. Hence, abnormally clustered tubular ER can be pathogenic in brain regions: disrupting mitochondrial integrity, inducing DNs formation and impairing cognitive function in AD and aging brains.
Collapse
Affiliation(s)
- Md. Golam Sharoar
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Qi Shi
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Yingying Ge
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Wanxia He
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Xiangyou Hu
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - George Perry
- The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249
| | - Xiongwei Zhu
- Department of Pathology, Case Western University School of Medicine, Cleveland, OH
| | - Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| |
Collapse
|
178
|
Lee JG, Takahama S, Zhang G, Tomarev SI, Ye Y. Unconventional secretion of misfolded proteins promotes adaptation to proteasome dysfunction in mammalian cells. Nat Cell Biol 2016; 18:765-76. [PMID: 27295555 PMCID: PMC10701763 DOI: 10.1038/ncb3372] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 05/11/2016] [Indexed: 12/14/2022]
Abstract
To safeguard proteomic integrity, cells rely on the proteasome to degrade aberrant polypeptides, but it is unclear how cells remove defective proteins that have escaped degradation owing to proteasome insufficiency or dysfunction. Here we report a pathway termed misfolding-associated protein secretion, which uses the endoplasmic reticulum (ER)-associated deubiquitylase USP19 to preferentially export aberrant cytosolic proteins. Intriguingly, the catalytic domain of USP19 possesses an unprecedented chaperone activity, allowing recruitment of misfolded proteins to the ER surface for deubiquitylation. Deubiquitylated cargos are encapsulated into ER-associated late endosomes and secreted to the cell exterior. USP19-deficient cells cannot efficiently secrete unwanted proteins, and grow more slowly than wild-type cells following exposure to a proteasome inhibitor. Together, our findings delineate a protein quality control (PQC) pathway that, unlike degradation-based PQC mechanisms, promotes protein homeostasis by exporting misfolded proteins through an unconventional protein secretion process.
Collapse
Affiliation(s)
- Jin-Gu Lee
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Shokichi Takahama
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
- Present address: Matsushita Project Laboratory, Center for AIDS Research, Kumamoto University, Kumamoto 860-0811, Japan
| | - Guofeng Zhang
- Biomedical Engineering and Physical Science Shared Resource, NIBIB, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Stanislav I. Tomarev
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Yihong Ye
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| |
Collapse
|
179
|
Intracellular and extracellular microRNA: An update on localization and biological role. ACTA ACUST UNITED AC 2016; 51:33-49. [PMID: 27396686 DOI: 10.1016/j.proghi.2016.06.001] [Citation(s) in RCA: 153] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 06/24/2016] [Accepted: 06/24/2016] [Indexed: 12/12/2022]
Abstract
MicroRNA (miRNA) is a class of small non-coding RNAs which mediate post-transcriptional gene silencing (PTGS) by sequence-specific inhibition of target mRNAs translation and/or lowering their half-lives in the cytoplasm. Together with their binding partners, Argonaute (AGO) proteins, miRNAs form cores of RNA-induced silencing complexes (RISC). Despite a substantial progress in understanding RISC structure, until recently little was known about its localization in the cell. This review is aimed to provide an overview of the emerging picture of miRNA and RISC localization and function both in the intracellular space and outside of the cell. In contrast to the common assumption that PTGS occurs in the cytoplasm, it was found to operate mainly on the membranes of the endoplasmic reticulum (ER). Besides ER membranes miRNAs were found in all main cellular compartments including nucleus, nucleolus and mitochondria where they regulate various processes including transcription, translation, alternative splicing and DNA repair. Moreover, a certain pool of miRNAs may not be associated with RISC and carry completely different functions. Finally, the discovery of cell-free miRNAs in all biological fluids suggests that miRNAs might also act as signaling molecules outside the cell, and may be utilized as biomarkers for a variety of diseases. In this review we discuss miRNA secretion mechanisms and possible pathways of cell-cell communication via miRNA-containing exosomes in vivo.
Collapse
|
180
|
Zhang H, Hu J. Shaping the Endoplasmic Reticulum into a Social Network. Trends Cell Biol 2016; 26:934-943. [PMID: 27339937 DOI: 10.1016/j.tcb.2016.06.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 05/25/2016] [Accepted: 06/02/2016] [Indexed: 10/21/2022]
Abstract
In eukaryotic cells, the endoplasmic reticulum (ER) is constructed as a network of tubules and sheets that exist in one continuous membrane system. Several classes of integral membrane protein have been shown to shape ER membranes. Functional studies using mutant proteins have begun to reveal the significance of ER morphology and membrane dynamics. In this review, we discuss the common protein modules and mechanisms that generate the characteristic shape of the ER. We also describe the cellular functions closely related to ER morphology, particularly contacts with other membrane systems, and their potential roles in the development of multicellular organisms.
Collapse
Affiliation(s)
- Hong Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Junjie Hu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| |
Collapse
|
181
|
Endoplasmic Reticulum: The Favorite Intracellular Niche for Viral Replication and Assembly. Viruses 2016; 8:v8060160. [PMID: 27338443 PMCID: PMC4926180 DOI: 10.3390/v8060160] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 05/23/2016] [Accepted: 05/26/2016] [Indexed: 02/07/2023] Open
Abstract
The endoplasmic reticulum (ER) is the largest intracellular organelle. It forms a complex network of continuous sheets and tubules, extending from the nuclear envelope (NE) to the plasma membrane. This network is frequently perturbed by positive-strand RNA viruses utilizing the ER to create membranous replication factories (RFs), where amplification of their genomes occurs. In addition, many enveloped viruses assemble progeny virions in association with ER membranes, and viruses replicating in the nucleus need to overcome the NE barrier, requiring transient changes of the NE morphology. This review first summarizes some key aspects of ER morphology and then focuses on the exploitation of the ER by viruses for the sake of promoting the different steps of their replication cycles.
Collapse
|
182
|
Abstract
PURPOSE OF REVIEW In this article, we summarize the present information related to the export of LDL-derived cholesterol from late endosomes, with a focus on Nieman-Pick disease, type C1 (NPC1) cholesterol delivery toward the endoplasmic reticulum (ER). We review data suggesting that several pathways may operate in parallel, including membrane transport routes and membrane contact sites (MCSs). RECENT FINDINGS There is increasing appreciation that MCSs provide an important mechanism for intermembrane lipid transfer. In late endosome-ER contacts, three protein bridges involving oxysterol binding protein related protein (ORP)1L-vesicle associated membrane protein-associated protein (VAP), steroidogenic acute regulatory protein (StAR)D3-VAP and ORP5-NPC1 proteins have been reported. How much they contribute to the flux of LDL-cholesterol to the ER is currently open. Studies for lipid transfer via MCSs have been most advanced in Saccharomyces cerevisiae. Recently, a new sterol-binding protein family conserved between yeast and man was identified. Its members localize at MCSs and were named lipid transfer protein anchored at membrane contact sites (Lam) proteins. In yeast, sterol transfer between the ER and the yeast lysosome may be facilitated by a Lam protein. SUMMARY Increasing insights into the role of MCSs in directional sterol delivery between membranes propose that they might provide routes for LDL-cholesterol transfer to the ER. Future work should reveal which specific contacts may operate for this, and how they are controlled by cholesterol homeostatic machineries.
Collapse
Affiliation(s)
- Simon G Pfisterer
- Department of Anatomy and Research Programs Unit, Faculty of Medicine, University of Helsinki, Finland and Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | | | | |
Collapse
|
183
|
Garrity AG, Wang W, Collier CM, Levey SA, Gao Q, Xu H. The endoplasmic reticulum, not the pH gradient, drives calcium refilling of lysosomes. eLife 2016; 5. [PMID: 27213518 PMCID: PMC4909396 DOI: 10.7554/elife.15887] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/20/2016] [Indexed: 12/15/2022] Open
Abstract
Impaired homeostasis of lysosomal Ca2+ causes lysosome dysfunction and lysosomal storage diseases (LSDs), but the mechanisms by which lysosomes acquire and refill Ca2+ are not known. We developed a physiological assay to monitor lysosomal Ca2+ store refilling using specific activators of lysosomal Ca2+ channels to repeatedly induce lysosomal Ca2+ release. In contrast to the prevailing view that lysosomal acidification drives Ca2+ into the lysosome, inhibiting the V-ATPase H+ pump did not prevent Ca2+ refilling. Instead, pharmacological depletion or chelation of Endoplasmic Reticulum (ER) Ca2+ prevented lysosomal Ca2+ stores from refilling. More specifically, antagonists of ER IP3 receptors (IP3Rs) rapidly and completely blocked Ca2+ refilling of lysosomes, but not in cells lacking IP3Rs. Furthermore, reducing ER Ca2+ or blocking IP3Rs caused a dramatic LSD-like lysosome storage phenotype. By closely apposing each other, the ER may serve as a direct and primary source of Ca2+for the lysosome. DOI:http://dx.doi.org/10.7554/eLife.15887.001
Collapse
Affiliation(s)
- Abigail G Garrity
- Neuroscience Program, University of Michigan, Ann Arbor, United States
| | - Wuyang Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Crystal Md Collier
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Sara A Levey
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Qiong Gao
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Haoxing Xu
- Neuroscience Program, University of Michigan, Ann Arbor, United States.,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| |
Collapse
|
184
|
Naguib A. Following the trail of lipids: Signals initiated by PI3K function at multiple cellular membranes. Sci Signal 2016; 9:re4. [DOI: 10.1126/scisignal.aad7885] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
185
|
Organelle remodeling at membrane contact sites. J Struct Biol 2016; 196:15-19. [PMID: 27181417 DOI: 10.1016/j.jsb.2016.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 05/11/2016] [Accepted: 05/12/2016] [Indexed: 01/17/2023]
Abstract
Cellular organelles must execute sophisticated biological processes to persist, and often communicate with one another to exchange metabolites and information. Recent studies suggest inter-organelle membrane contact sites (MCSs) are hubs for this cellular cross-talk. MCSs also govern membrane remodeling, thus controlling aspects of organelle shape, identity, and function. Here, we summarize three emerging phenomena that MCSs appear to govern: 1) organelle identity via the non-vesicular exchange of lipids, 2) mitochondrial shape and division, and 3) endosomal migration in response to sterol trafficking. We also discuss the role for ER-endolysosomal contact sites in cholesterol metabolism, and the potential biomedical importance this holds. Indeed, the emerging field inter-organellar cross-talk promises substantial advances in the fields of lipid metabolism and cell signaling.
Collapse
|
186
|
Okeke E, Dingsdale H, Parker T, Voronina S, Tepikin AV. Endoplasmic reticulum-plasma membrane junctions: structure, function and dynamics. J Physiol 2016; 594:2837-47. [PMID: 26939537 DOI: 10.1113/jp271142] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 02/13/2016] [Indexed: 12/20/2022] Open
Abstract
Endoplasmic reticulum (ER)-plasma membrane (PM) junctions are contact sites between the ER and the PM; the distance between the two organelles in the junctions is below 40 nm and the membranes are connected by protein tethers. A number of molecular tools and technical approaches have been recently developed to visualise, modify and characterise properties of ER-PM junctions. The junctions serve as the platforms for lipid exchange between the organelles and for cell signalling, notably Ca(2+) and cAMP signalling. Vice versa, signalling events regulate the development and properties of the junctions. Two Ca(2+) -dependent mechanisms of de novo formation of ER-PM junctions have been recently described and characterised. The junction-forming proteins and lipids are currently the focus of vigorous investigation. Junctions can be relatively short-lived and simple structures, forming and dissolving on the time scale of a few minutes. However, complex, sophisticated and multifunctional ER-PM junctions, capable of attracting numerous protein residents and other cellular organelles, have been described in some cell types. The road from simplicity to complexity, i.e. the transformation from simple 'nascent' ER-PM junctions to advanced stable multiorganellar complexes, is likely to become an attractive research avenue for current and future junctologists. Another area of considerable research interest is the downstream cellular processes that can be activated by specific local signalling events in the ER-PM junctions. Studies of the cell physiology and indeed pathophysiology of ER-PM junctions have already produced some surprising discoveries, likely to expand with advances in our understanding of these remarkable organellar contact sites.
Collapse
Affiliation(s)
- Emmanuel Okeke
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Hayley Dingsdale
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Tony Parker
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Svetlana Voronina
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Alexei V Tepikin
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| |
Collapse
|
187
|
Dummer PD, Limou S, Rosenberg AZ, Heymann J, Nelson G, Winkler CA, Kopp JB. APOL1 Kidney Disease Risk Variants: An Evolving Landscape. Semin Nephrol 2016. [PMID: 26215860 DOI: 10.1016/j.semnephrol.2015.04.008] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Apolipoprotein L1 (APOL1) genetic variants account for much of the excess risk of chronic and end-stage kidney disease, which results in a significant global health disparity for persons of African ancestry. We estimate the lifetime risk of kidney disease in APOL1 dual-risk allele individuals to be at least 15%. Experimental evidence suggests a direct role of APOL1 in pore formation, cellular injury, and programmed cell death in renal injury. The APOL1 BH3 motif, often associated with cell death, is unlikely to play a role in APOL1-induced cytotoxicity because it is not conserved within the APOL family and is dispensable for cell death in vitro. We discuss two models for APOL1 trypanolytic activity: one involving lysosome permeabilization and another involving colloid-osmotic swelling of the cell body, as well as their relevance to human pathophysiology. Experimental evidence from human cell culture models suggests that both mechanisms may be operative. A systems biology approach whereby APOL1-associated perturbations in gene and protein expression in affected individuals are correlated with molecular pathways may be productive to elucidate APOL1 function in vivo.
Collapse
Affiliation(s)
- Patrick D Dummer
- Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Sophie Limou
- Molecular Epidemiology Genetics Section, Center for Cancer Research, National Cancer Institute, Frederick MD
| | - Avi Z Rosenberg
- Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD; Department of Pathology Johns Hopkins University, Baltimore, MD
| | - Jurgen Heymann
- Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - George Nelson
- Molecular Epidemiology Genetics Section, Center for Cancer Research, National Cancer Institute, Frederick MD
| | - Cheryl A Winkler
- Molecular Epidemiology Genetics Section, Center for Cancer Research, National Cancer Institute, Frederick MD
| | - Jeffrey B Kopp
- Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD.
| |
Collapse
|
188
|
Tan X, Lambert PF, Rapraeger AC, Anderson RA. Stress-Induced EGFR Trafficking: Mechanisms, Functions, and Therapeutic Implications. Trends Cell Biol 2016; 26:352-366. [PMID: 26827089 PMCID: PMC5120732 DOI: 10.1016/j.tcb.2015.12.006] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 12/27/2015] [Accepted: 12/31/2015] [Indexed: 12/13/2022]
Abstract
Epidermal growth factor receptor (EGFR) has fundamental roles in normal physiology and cancer, making it a rational target for cancer therapy. Surprisingly, however, inhibitors that target canonical, ligand-stimulated EGFR signaling have proven to be largely ineffective in treating many EGFR-dependent cancers. Recent evidence indicates that both intrinsic and therapy-induced cellular stress triggers robust, noncanonical pathways of ligand-independent EGFR trafficking and signaling, which provides cancer cells with a survival advantage and resistance to therapeutics. Here, we review the mechanistic regulation of noncanonical EGFR trafficking and signaling, and the pathological and therapeutic stresses that activate it. We also discuss the implications of this pathway in clinical treatment of EGFR-overexpressing cancers.
Collapse
Affiliation(s)
- Xiaojun Tan
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Paul F Lambert
- Department of Oncology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA; McArdle Laboratory for Cancer Research, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Alan C Rapraeger
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Richard A Anderson
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA.
| |
Collapse
|
189
|
Abstract
Extracellular stimuli evoke the synthesis of intracellular second messengers, several of which couple to the release of Ca2+ from Ca2+-storing organelles via activation of cognate organellar Ca2+-channel complexes. The archetype is the inositol 1,4,5-trisphosphate (IP3) and IP3 receptor (IP3R) on the endoplasmic reticulum (ER). A less understood, parallel Ca2+ signalling cascade is that involving the messenger nicotinic acid adenine dinucleotide phosphate (NAADP) that couples to Ca2+ release from acidic Ca2+ stores [e.g. endo-lysosomes, secretory vesicles, lysosome-related organelles (LROs)]. NAADP-induced Ca2+ release absolutely requires organellar TPCs (two-pore channels). This review discusses how ER and acidic Ca2+ stores physically and functionally interact to generate and shape global and local Ca2+ signals, with particular emphasis on the two-way dialogue between these two organelles.
Collapse
|
190
|
Hariri H, Ugrankar R, Liu Y, Henne WM. Inter-organelle ER-endolysosomal contact sites in metabolism and disease across evolution. Commun Integr Biol 2016; 9:e1156278. [PMID: 27489577 PMCID: PMC4951168 DOI: 10.1080/19420889.2016.1156278] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 02/13/2016] [Indexed: 12/29/2022] Open
Abstract
Since their initial observation, contact sites formed between different organelles have transitioned from ignored curiosities to recognized centers for the exchange of metabolites and lipids. Contact formed between the ER and endomembrane system (eg. the plasma membrane, endosomes, and lysosomes) is of particular biomedical interest, as it governs aspects of lipid metabolism, organelle identity, and cell signaling. Here, we review the field of ER-endolysosomal communication from the perspective of three model systems: budding yeast, the fruit fly D. melanogaster, and mammals. From this broad perspective, inter-organelle communication displays a consistent role in metabolic regulation that was differentially tuned during the development of complex metazoan life. We also examine the current state of understanding of lipid exchange between organelles, and discuss molecular mechanisms by which this occurs.
Collapse
Affiliation(s)
- Hanaa Hariri
- Department of Cell Biology, UT Southwestern Medical Center , Dallas, TX, USA
| | - Rupali Ugrankar
- Department of Cell Biology, UT Southwestern Medical Center , Dallas, TX, USA
| | - Yang Liu
- Department of Cell Biology, UT Southwestern Medical Center , Dallas, TX, USA
| | - W Mike Henne
- Department of Cell Biology, UT Southwestern Medical Center , Dallas, TX, USA
| |
Collapse
|
191
|
Lipid transfer and metabolism across the endolysosomal-mitochondrial boundary. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:880-894. [PMID: 26852832 DOI: 10.1016/j.bbalip.2016.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 01/30/2016] [Accepted: 02/03/2016] [Indexed: 01/10/2023]
Abstract
Lysosomes and mitochondria occupy a central stage in the maintenance of cellular homeostasis, by playing complementary roles in nutrient sensing and energy metabolism. Specifically, these organelles function as signaling hubs that integrate environmental and endogenous stimuli with specific metabolic responses. In particular, they control various lipid biosynthetic and degradative pipelines, either directly or indirectly, by regulating major cellular metabolic pathways, and by physical and functional connections established with each other and with other organelles. Membrane contact sites allow the exchange of ions and molecules between organelles, even without membrane fusion, and are privileged routes for lipid transfer among different membrane compartments. These inter-organellar connections typically involve the endoplasmic reticulum. Direct membrane contacts have now been described also between lysosomes, autophagosomes, lipid droplets, and mitochondria. This review focuses on these recently identified membrane contact sites, and on their role in lipid biosynthesis, exchange, turnover and catabolism. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
Collapse
|
192
|
Phillips MJ, Voeltz GK. Structure and function of ER membrane contact sites with other organelles. Nat Rev Mol Cell Biol 2015; 17:69-82. [PMID: 26627931 DOI: 10.1038/nrm.2015.8] [Citation(s) in RCA: 645] [Impact Index Per Article: 71.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The endoplasmic reticulum (ER) is the largest organelle in the cell, and its functions have been studied for decades. The past several years have provided novel insights into the existence of distinct domains between the ER and other organelles, known as membrane contact sites (MCSs). At these contact sites, organelle membranes are closely apposed and tethered, but do not fuse. Here, various protein complexes can work in concert to perform specialized functions such as binding, sensing and transferring molecules, as well as engaging in organelle biogenesis and dynamics. This Review describes the structure and functions of MCSs, primarily focusing on contacts of the ER with mitochondria and endosomes.
Collapse
Affiliation(s)
- Melissa J Phillips
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA
| | - Gia K Voeltz
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA
| |
Collapse
|
193
|
Guimaraes SC, Schuster M, Bielska E, Dagdas G, Kilaru S, Meadows BRA, Schrader M, Steinberg G. Peroxisomes, lipid droplets, and endoplasmic reticulum "hitchhike" on motile early endosomes. J Cell Biol 2015; 211:945-54. [PMID: 26620910 PMCID: PMC4674278 DOI: 10.1083/jcb.201505086] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 10/26/2015] [Indexed: 02/04/2023] Open
Abstract
Intracellular transport is mediated by molecular motors that bind cargo to be transported along the cytoskeleton. Here, we report, for the first time, that peroxisomes (POs), lipid droplets (LDs), and the endoplasmic reticulum (ER) rely on early endosomes (EEs) for intracellular movement in a fungal model system. We show that POs undergo kinesin-3- and dynein-dependent transport along microtubules. Surprisingly, kinesin-3 does not colocalize with POs. Instead, the motor moves EEs that drag the POs through the cell. PO motility is abolished when EE motility is blocked in various mutants. Most LD and ER motility also depends on EE motility, whereas mitochondria move independently of EEs. Covisualization studies show that EE-mediated ER motility is not required for PO or LD movement, suggesting that the organelles interact with EEs independently. In the absence of EE motility, POs and LDs cluster at the growing tip, whereas ER is partially retracted to subapical regions. Collectively, our results show that moving EEs interact transiently with other organelles, thereby mediating their directed transport and distribution in the cell.
Collapse
Affiliation(s)
| | - Martin Schuster
- Biosciences, University of Exeter, Exeter EX4 4QD, England, UK
| | - Ewa Bielska
- Biosciences, University of Exeter, Exeter EX4 4QD, England, UK
| | - Gulay Dagdas
- Biosciences, University of Exeter, Exeter EX4 4QD, England, UK
| | - Sreedhar Kilaru
- Biosciences, University of Exeter, Exeter EX4 4QD, England, UK
| | - Ben R A Meadows
- Biosciences, University of Exeter, Exeter EX4 4QD, England, UK
| | | | - Gero Steinberg
- Biosciences, University of Exeter, Exeter EX4 4QD, England, UK
| |
Collapse
|
194
|
ER network homeostasis is critical for plant endosome streaming and endocytosis. Cell Discov 2015; 1:15033. [PMID: 27462431 PMCID: PMC4860783 DOI: 10.1038/celldisc.2015.33] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 09/20/2015] [Indexed: 12/21/2022] Open
Abstract
Eukaryotic cells internalize cargo at the plasma membrane via endocytosis, a vital process that is accomplished through a complex network of endosomal organelles. In mammalian cells, the ER is in close association with endosomes and regulates their fission. Nonetheless, the physiological role of such interaction on endocytosis is yet unexplored. Here, we probed the existence of ER–endosome association in plant cells and assayed its physiological role in endocytosis. Through live-cell imaging and electron microscopy studies, we established that endosomes are extensively associated with the plant ER, supporting conservation of interaction between heterotypic organelles in evolutionarily distant kingdoms. Furthermore, by analyzing ER–endosome dynamics in genetic backgrounds with defects in ER structure and movement, we also established that the ER network integrity is necessary for homeostasis of the distribution and streaming of various endosome populations as well as for efficient endocytosis. These results support a novel model that endocytosis homeostasis depends on a spatiotemporal control of the endosome dynamics dictated by the ER membrane network.
Collapse
|
195
|
Tan X, Thapa N, Choi S, Anderson RA. Emerging roles of PtdIns(4,5)P2--beyond the plasma membrane. J Cell Sci 2015; 128:4047-56. [PMID: 26574506 PMCID: PMC4712784 DOI: 10.1242/jcs.175208] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Phosphoinositides are a collection of lipid messengers that regulate most subcellular processes. Amongst the seven phosphoinositide species, the roles for phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] at the plasma membrane, such as in endocytosis, exocytosis, actin polymerization and focal adhesion assembly, have been extensively studied. Recent studies have argued for the existence of PtdIns(4,5)P2 at multiple intracellular compartments, including the nucleus, endosomes, lysosomes, autolysosomes, autophagic precursor membranes, ER, mitochondria and the Golgi complex. Although the generation, regulation and functions of PtdIns(4,5)P2 are less well-defined in most other intracellular compartments, accumulating evidence demonstrates crucial roles for PtdIns(4,5)P2 in endolysosomal trafficking, endosomal recycling, as well as autophagosomal pathways, which are the focus of this Commentary. We summarize and discuss how phosphatidylinositol phosphate kinases, PtdIns(4,5)P2 and PtdIns(4,5)P2-effectors regulate these intracellular protein and membrane trafficking events.
Collapse
Affiliation(s)
- Xiaojun Tan
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Narendra Thapa
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Suyong Choi
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Richard A Anderson
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA Program in Cellular and Molecular Biology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| |
Collapse
|
196
|
Henne WM, Zhu L, Balogi Z, Stefan C, Pleiss JA, Emr SD. Mdm1/Snx13 is a novel ER-endolysosomal interorganelle tethering protein. J Cell Biol 2015; 210:541-51. [PMID: 26283797 PMCID: PMC4539980 DOI: 10.1083/jcb.201503088] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Mdm1 is a novel interorganelle tethering protein that localizes to yeast ER–vacuole/lysosome junctions, and Mdm1 truncations analogous to disease-associated Snx14 alleles fail to tether the ER and vacuole and perturb sphingolipid metabolism. Although endolysosomal trafficking is well defined, how it is regulated and coordinates with cellular metabolism is unclear. To identify genes governing endolysosomal dynamics, we conducted a global fluorescence-based screen to reveal endomembrane effector genes. Screening implicated Phox (PX) domain–containing protein Mdm1 in endomembrane dynamics. Surprisingly, we demonstrate that Mdm1 is a novel interorganelle tethering protein that localizes to endoplasmic reticulum (ER)–vacuole/lysosome membrane contact sites (MCSs). We show that Mdm1 is ER anchored and contacts the vacuole surface in trans via its lipid-binding PX domain. Strikingly, overexpression of Mdm1 induced ER–vacuole hypertethering, underscoring its role as an interorganelle tether. We also show that Mdm1 and its paralogue Ydr179w-a (named Nvj3 in this study) localize to ER–vacuole MCSs independently of established tether Nvj1. Finally, we find that Mdm1 truncations analogous to neurological disease–associated SNX14 alleles fail to tether the ER and vacuole and perturb sphingolipid metabolism. Our work suggests that human Mdm1 homologues may play previously unappreciated roles in interorganelle communication and lipid metabolism.
Collapse
Affiliation(s)
- W Mike Henne
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Lu Zhu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853 Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Zsolt Balogi
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853 Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Christopher Stefan
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, England, UK
| | - Jeffrey A Pleiss
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Scott D Emr
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853 Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| |
Collapse
|
197
|
van Bergeijk P, Hoogenraad CC, Kapitein LC. Right Time, Right Place: Probing the Functions of Organelle Positioning. Trends Cell Biol 2015; 26:121-134. [PMID: 26541125 DOI: 10.1016/j.tcb.2015.10.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 09/30/2015] [Accepted: 10/01/2015] [Indexed: 10/22/2022]
Abstract
The proper spatial arrangement of organelles underlies many cellular processes including signaling, polarization, and growth. Despite the importance of local positioning, the precise connection between subcellular localization and organelle function is often not fully understood. To address this, recent studies have developed and employed different strategies to directly manipulate organelle distributions, such as the use of (light-sensitive) heterodimerization to control the interaction between selected organelles and specific motor proteins, adaptor molecules, or anchoring factors. We review here the importance of subcellular localization as well as tools to control local organelle positioning. Because these approaches allow spatiotemporal control of organelle distribution, they will be invaluable tools to unravel local functioning and the mechanisms that control positioning.
Collapse
Affiliation(s)
- Petra van Bergeijk
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Lukas C Kapitein
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands.
| |
Collapse
|
198
|
Moruno Manchon JF, Uzor NE, Dabaghian Y, Furr-Stimming EE, Finkbeiner S, Tsvetkov AS. Cytoplasmic sphingosine-1-phosphate pathway modulates neuronal autophagy. Sci Rep 2015; 5:15213. [PMID: 26477494 PMCID: PMC4609990 DOI: 10.1038/srep15213] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/21/2015] [Indexed: 12/13/2022] Open
Abstract
Autophagy is an important homeostatic mechanism that eliminates long-lived proteins, protein aggregates and damaged organelles. Its dysregulation is involved in many neurodegenerative disorders. Autophagy is therefore a promising target for blunting neurodegeneration. We searched for novel autophagic pathways in primary neurons and identified the cytosolic sphingosine-1-phosphate (S1P) pathway as a regulator of neuronal autophagy. S1P, a bioactive lipid generated by sphingosine kinase 1 (SK1) in the cytoplasm, is implicated in cell survival. We found that SK1 enhances flux through autophagy and that S1P-metabolizing enzymes decrease this flux. When autophagy is stimulated, SK1 relocalizes to endosomes/autophagosomes in neurons. Expression of a dominant-negative form of SK1 inhibits autophagosome synthesis. In a neuron model of Huntington’s disease, pharmacologically inhibiting S1P-lyase protected neurons from mutant huntingtin-induced neurotoxicity. These results identify the S1P pathway as a novel regulator of neuronal autophagy and provide a new target for developing therapies for neurodegenerative disorders.
Collapse
Affiliation(s)
| | - Ndidi-Ese Uzor
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, TX 77030.,The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030
| | - Yuri Dabaghian
- The Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030.,Department of Computational and Applied Mathematics, Rice University, Houston, TX 77005
| | | | - Steven Finkbeiner
- Gladstone Institute of Neurological Disease and the Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, CA 94158.,Departments of Neurology and Physiology, University of California, San Francisco, CA 94143
| | - Andrey S Tsvetkov
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, TX 77030.,The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030
| |
Collapse
|
199
|
Wijdeven RH, Jongsma MLM, Neefjes J, Berlin I. ER contact sites direct late endosome transport. Bioessays 2015; 37:1298-302. [DOI: 10.1002/bies.201500095] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Ruud H. Wijdeven
- Division of Cell Biology; The Netherlands Cancer Institute; Amsterdam The Netherlands
| | - Marlieke L. M. Jongsma
- Department of Immunopathology; Sanquin Research and Landsteiner Laboratory AMC/UvA; Amsterdam The Netherlands
| | - Jacques Neefjes
- Division of Cell Biology; The Netherlands Cancer Institute; Amsterdam The Netherlands
| | - Ilana Berlin
- Division of Cell Biology; The Netherlands Cancer Institute; Amsterdam The Netherlands
| |
Collapse
|
200
|
Naj X, Linder S. ER-Coordinated Activities of Rab22a and Rab5a Drive Phagosomal Compaction and Intracellular Processing of Borrelia burgdorferi by Macrophages. Cell Rep 2015; 12:1816-30. [DOI: 10.1016/j.celrep.2015.08.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 06/24/2015] [Accepted: 08/08/2015] [Indexed: 01/26/2023] Open
|