51
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Hou W, Jerome-Majewska LA. TMED2/emp24 is required in both the chorion and the allantois for placental labyrinth layer development. Dev Biol 2018; 444:20-32. [PMID: 30236446 DOI: 10.1016/j.ydbio.2018.09.012] [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: 06/24/2018] [Revised: 09/10/2018] [Accepted: 09/10/2018] [Indexed: 01/08/2023]
Abstract
TMED2, a member of the transmembrane emp24 domain (TMED) family, is required for transport of cargo proteins between the ER and Golgi. TMED2 is also important for normal morphogenesis of mouse embryos and their associated placenta, and in fact Tmed2 homozygous mutant embryos arrest at mid-gestation due to a failure of placental labyrinth layer formation. Differentiation of the placental labyrinth layer depends on chorioallantoic attachment (contact between the chorion and allantois), and branching morphogenesis (mingling of cells from these two tissues). Since Tmed2 mRNA was found in both the chorion and allantois, and 50% of Tmed2 homozygous mutant embryos failed to undergo chorioallantoic attachment, the tissue-specific requirement of Tmed2 during placental labyrinth layer formation remained a mystery. Herein, we report differential localization of TMED2 protein in the chorion and allantois, abnormal ER retention of Fibronectin in Tmed2 homozygous mutant allantoises and cell-autonomous requirement for Tmed2 in the chorion for chorioallantoic attachment and fusion. Using an ex vivo model of explanted chorions and allantoises, we showed that chorioallantoic attachment failed to occur in 50% of samples when homozygous mutant chorions were recombined with wild type allantoises. Furthermore, though expression of genes associated with trophoblast differentiation was maintained in Tmed2 mutant chorions with chorioallantoic attachment, expression of these genes was attenuated. In addition, Tmed2 homozygous mutant allantoises could undergo branching morphogenesis, however the region of mixing between mutant and wild type cells was reduced, and expression of genes associated with trophoblast differentiation was also attenuated. Our data also suggest that Fibronectin is a cargo protein of TMED2 and indicates that Tmed2 is required cell-autonomously and non-autonomously in the chorion and the allantois for placental labyrinth layer formation.
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Affiliation(s)
- Wenyang Hou
- Department of Human Genetics, McGill University, 1205 Avenue Docteur Penfield, N5/13, Montreal, QC, Canada
| | - Loydie A Jerome-Majewska
- Department of Human Genetics, McGill University, 1205 Avenue Docteur Penfield, N5/13, Montreal, QC, Canada; Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada; Department of Pediatrics, McGill University, 1001 Decarie Blvd, EM02210, Montreal, QC, Canada H4A 3J1; McGill University Health Centre Glen Site, 1001 Decarie Blvd, EM0.2210, Montreal, QC, Canada H4A 3J1.
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52
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Aridor M. COPII gets in shape: Lessons derived from morphological aspects of early secretion. Traffic 2018; 19:823-839. [DOI: 10.1111/tra.12603] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/26/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Meir Aridor
- Department of Cell Biology; University of Pittsburgh School of Medicine; Pittsburgh Pennsylvania
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53
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Yeats TH, Bacic A, Johnson KL. Plant glycosylphosphatidylinositol anchored proteins at the plasma membrane-cell wall nexus. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2018; 60:649-669. [PMID: 29667761 DOI: 10.1111/jipb.12659] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 04/16/2018] [Indexed: 05/17/2023]
Abstract
Approximately 1% of plant proteins are predicted to be post-translationally modified with a glycosylphosphatidylinositol (GPI) anchor that tethers the polypeptide to the outer leaflet of the plasma membrane. Whereas the synthesis and structure of GPI anchors is largely conserved across eukaryotes, the repertoire of functional domains present in the GPI-anchored proteome has diverged substantially. In plants, this includes a large fraction of the GPI-anchored proteome being further modified with plant-specific arabinogalactan (AG) O-glycans. The importance of the GPI-anchored proteome to plant development is underscored by the fact that GPI biosynthetic null mutants exhibit embryo lethality. Mutations in genes encoding specific GPI-anchored proteins (GAPs) further supports their contribution to diverse biological processes, occurring at the interface of the plasma membrane and cell wall, including signaling, cell wall metabolism, cell wall polymer cross-linking, and plasmodesmatal transport. Here, we review the literature concerning plant GPI-anchored proteins, in the context of their potential to act as molecular hubs that mediate interactions between the plasma membrane and the cell wall, and their potential to transduce the signal into the protoplast and, thereby, activate signal transduction pathways.
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Affiliation(s)
- Trevor H Yeats
- School of Integrated Plant Sciences, Section of Plant Biology, Cornell University, Ithaca, NY 14853, USA
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY 14853, USA
| | - Antony Bacic
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of BioSciences, University of Melbourne, Parkville, Victoria 3010, Australia
- La Trobe Institute for Agriculture & Food, Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Kim L Johnson
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of BioSciences, University of Melbourne, Parkville, Victoria 3010, Australia
- La Trobe Institute for Agriculture & Food, Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Victoria 3086, Australia
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54
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Lebreton S, Zurzolo C, Paladino S. Organization of GPI-anchored proteins at the cell surface and its physiopathological relevance. Crit Rev Biochem Mol Biol 2018; 53:403-419. [PMID: 30040489 DOI: 10.1080/10409238.2018.1485627] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are a class of proteins attached to the extracellular leaflet of the plasma membrane via a post-translational modification, the glycolipid anchor. The presence of both glycolipid anchor and protein portion confers them unique features. GPI-APs are expressed in all eukaryotes, from fungi to plants and animals. They display very diverse functions ranging from enzymatic activity, signaling, cell adhesion, cell wall metabolism, neuritogenesis, and immune response. Likewise other plasma membrane proteins, the spatio-temporal organization of GPI-APs is critical for their biological activities in physiological conditions. In this review, we will summarize the latest findings on plasma membrane organization of GPI-APs and the mechanism of its regulation in different cell types. We will also examine the involvement of specific GPI-APs namely the prion protein PrPC, the Folate Receptor alpha and the urokinase plasminogen activator receptor in human diseases focusing on neurodegenerative diseases and cancer.
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Affiliation(s)
- Stéphanie Lebreton
- a Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur , Paris , France
| | - Chiara Zurzolo
- a Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur , Paris , France
| | - Simona Paladino
- b Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II , Napoli , Italy.,c CEINGE Biotecnologie Avanzate , Napoli , Italy
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55
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Abstract
The coat protein complex I (COPI) allows the precise sorting of lipids and proteins between Golgi cisternae and retrieval from the Golgi to the ER. This essential role maintains the identity of the early secretory pathway and impinges on key cellular processes, such as protein quality control. In this Cell Science at a Glance and accompanying poster, we illustrate the different stages of COPI-coated vesicle formation and revisit decades of research in the context of recent advances in the elucidation of COPI coat structure. By calling attention to an array of questions that have remained unresolved, this review attempts to refocus the perspectives of the field.
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Affiliation(s)
- Eric C Arakel
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany .,Max-Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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56
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Kanellopoulos AH, Koenig J, Huang H, Pyrski M, Millet Q, Lolignier S, Morohashi T, Gossage SJ, Jay M, Linley JE, Baskozos G, Kessler BM, Cox JJ, Dolphin AC, Zufall F, Wood JN, Zhao J. Mapping protein interactions of sodium channel Na V1.7 using epitope-tagged gene-targeted mice. EMBO J 2018; 37:427-445. [PMID: 29335280 PMCID: PMC5793798 DOI: 10.15252/embj.201796692] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 11/30/2017] [Accepted: 12/05/2017] [Indexed: 11/24/2022] Open
Abstract
The voltage-gated sodium channel NaV1.7 plays a critical role in pain pathways. We generated an epitope-tagged NaV1.7 mouse that showed normal pain behaviours to identify channel-interacting proteins. Analysis of NaV1.7 complexes affinity-purified under native conditions by mass spectrometry revealed 267 proteins associated with Nav1.7 in vivo The sodium channel β3 (Scn3b), rather than the β1 subunit, complexes with Nav1.7, and we demonstrate an interaction between collapsing-response mediator protein (Crmp2) and Nav1.7, through which the analgesic drug lacosamide regulates Nav1.7 current density. Novel NaV1.7 protein interactors including membrane-trafficking protein synaptotagmin-2 (Syt2), L-type amino acid transporter 1 (Lat1) and transmembrane P24-trafficking protein 10 (Tmed10) together with Scn3b and Crmp2 were validated by co-immunoprecipitation (Co-IP) from sensory neuron extract. Nav1.7, known to regulate opioid receptor efficacy, interacts with the G protein-regulated inducer of neurite outgrowth (Gprin1), an opioid receptor-binding protein, demonstrating a physical and functional link between Nav1.7 and opioid signalling. Further information on physiological interactions provided with this normal epitope-tagged mouse should provide useful insights into the many functions now associated with the NaV1.7 channel.
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Affiliation(s)
| | - Jennifer Koenig
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Honglei Huang
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of Oxford, Oxford, UK
| | - Martina Pyrski
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Queensta Millet
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Stéphane Lolignier
- Molecular Nociception Group, WIBR, University College London, London, UK
- Université Clermont Auvergne, Inserm U1107 Neuro-Dol, Pharmacologie Fondamentale et Clinique de la Douleur, Clermont-Ferrand, France
| | - Toru Morohashi
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Samuel J Gossage
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Maude Jay
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - John E Linley
- Molecular Nociception Group, WIBR, University College London, London, UK
- Neuroscience, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | | | - Benedikt M Kessler
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of Oxford, Oxford, UK
| | - James J Cox
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Frank Zufall
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - John N Wood
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Jing Zhao
- Molecular Nociception Group, WIBR, University College London, London, UK
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57
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Starr TL, Gonçalves AP, Meshgin N, Glass NL. The major cellulases CBH-1 and CBH-2 of Neurospora crassa rely on distinct ER cargo adaptors for efficient ER-exit. Mol Microbiol 2017; 107:229-248. [PMID: 29131484 DOI: 10.1111/mmi.13879] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2017] [Indexed: 12/17/2022]
Abstract
Filamentous fungi are native secretors of lignocellulolytic enzymes and are used as protein-producing factories in the industrial biotechnology sector. Despite the importance of these organisms in industry, relatively little is known about the filamentous fungal secretory pathway or how it might be manipulated for improved protein production. Here, we use Neurospora crassa as a model filamentous fungus to interrogate the requirements for trafficking of cellulase enzymes from the endoplasmic reticulum to the Golgi. We characterized the localization and interaction properties of the p24 and ERV-29 cargo adaptors, as well as their role in cellulase enzyme trafficking. We find that the two most abundantly secreted cellulases, CBH-1 and CBH-2, depend on distinct ER cargo adaptors for efficient exit from the ER. CBH-1 depends on the p24 proteins, whereas CBH-2 depends on the N. crassa homolog of yeast Erv29p. This study provides a first step in characterizing distinct trafficking pathways of lignocellulolytic enzymes in filamentous fungi.
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Affiliation(s)
- Trevor L Starr
- The Energy Biosciences Institute, The University of California, Berkeley, CA 94720, USA
| | - A Pedro Gonçalves
- The Energy Biosciences Institute, The University of California, Berkeley, CA 94720, USA.,Plant and Microbial Biology Department, The University of California, Berkeley, CA 94720, USA
| | - Neeka Meshgin
- The Energy Biosciences Institute, The University of California, Berkeley, CA 94720, USA
| | - N Louise Glass
- The Energy Biosciences Institute, The University of California, Berkeley, CA 94720, USA.,Plant and Microbial Biology Department, The University of California, Berkeley, CA 94720, USA.,Environmental Genomics and Systems Biology Division, The Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
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58
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Abstract
TMED2 is involved in morphogenesis of the mouse embryo and placenta. We found that expression of TMED2 was higher in epithelial ovarian cancer tissues than normal ovarian tissues. Silencing TMED2 decreased cell proliferation, migration, and invasion. Ectopic expression of TMED2 increased cell proliferation, migration and invasion. Silencing TMED2 inhibited ovarian cancer growth in mice. Silencing TMED2 inhibited IGF2/IGF1R/PI3K/Akt pathway. In agreement, ectopically expressed TMED2 activated IGF2/IGF1R/PI3K/Akt pathway. Mechanistic study revealed that TMED2 directly binds to AKT2, thereby facilitating its phosphorylation. We also found that TMED2 increased IGF1R expression by competing for miR-30a. Thus, TMED2 is oncogenic and a potential target for epithelial ovarian cancer therapy.
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59
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Cupino TL, Watson BA, Cupino AC, Oda K, Ghamsary MG, Soriano S, Kirsch WM. Stability and bioactivity of chitosan as a transfection agent in primary human cell cultures: A case for chitosan-only controls. Carbohydr Polym 2017; 180:376-384. [PMID: 29103517 DOI: 10.1016/j.carbpol.2017.10.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/21/2017] [Accepted: 10/04/2017] [Indexed: 01/04/2023]
Abstract
Chitosan polymers (Cs), from which microparticles (CsM) may be precipitated to deliver various intracellular payloads, are generally considered biologically inert. We examined the impact of cell culture conditions on CsM size and the effect of chitosan on CD59 expression in primary human smooth muscle cells. We found that particle concentration and incubation time in biological buffers augmented particle size. Between pH 7.0 and pH 7.5, CsM size increased abruptly. We utilized CsM containing a plasmid with a gene for CD59 (pCsM) to transfect cells. Both CD59 mRNA and the number of CD59-positive cells were increased after pCsM treatment. Unexpectedly, CsM also augmented the number of CD59-positive cells. Cs alone enhanced CD59 expression more potently than either pCSM or CsM. This observation strongly suggests that chitosan is in fact bioactive and that chitosan-only controls should be included to avoid misattributing the activity of the delivery agent with that of the payload.
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Affiliation(s)
- Tanya L Cupino
- Neurosurgery Center for Research, Training and Education, Loma Linda University School of Medicine, Loma Linda, CA, United States; Division of Microbiology and Molecular Genetics, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, United States.
| | - Billy A Watson
- Division of Microbiology and Molecular Genetics, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, United States; Division of Human Anatomy, Department of Pathology and Human Anatomy, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Alan C Cupino
- Department of Epidemiology and Biostatistics, Loma Linda University School of Public Health, Loma Linda, CA, United States
| | - Keiji Oda
- Department of Epidemiology and Biostatistics, Loma Linda University School of Public Health, Loma Linda, CA, United States
| | - Mark G Ghamsary
- Department of Epidemiology and Biostatistics, Loma Linda University School of Public Health, Loma Linda, CA, United States (Retired)
| | - Salvador Soriano
- Division of Human Anatomy, Department of Pathology and Human Anatomy, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Wolff M Kirsch
- Neurosurgery Center for Research, Training and Education, Loma Linda University School of Medicine, Loma Linda, CA, United States.
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60
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Joo JH, Wang B, Frankel E, Ge L, Xu L, Iyengar R, Li-Harms X, Wright C, Shaw TI, Lindsten T, Green DR, Peng J, Hendershot LM, Kilic F, Sze JY, Audhya A, Kundu M. The Noncanonical Role of ULK/ATG1 in ER-to-Golgi Trafficking Is Essential for Cellular Homeostasis. Mol Cell 2017; 62:491-506. [PMID: 27203176 DOI: 10.1016/j.molcel.2016.04.020] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/07/2016] [Accepted: 04/19/2016] [Indexed: 01/08/2023]
Abstract
ULK1 and ULK2 are thought to be essential for initiating autophagy, and Ulk1/2-deficient mice die perinatally of autophagy-related defects. Therefore, we used a conditional knockout approach to investigate the roles of ULK1/2 in the brain. Although the mice showed neuronal degeneration, the neurons showed no accumulation of P62(+)/ubiquitin(+) inclusions or abnormal membranous structures, which are observed in mice lacking other autophagy genes. Rather, neuronal death was associated with activation of the unfolded protein response (UPR) pathway. An unbiased proteomics approach identified SEC16A as an ULK1/2 interaction partner. ULK-mediated phosphorylation of SEC16A regulated the assembly of endoplasmic reticulum (ER) exit sites and ER-to-Golgi trafficking of specific cargo, and did not require other autophagy proteins (e.g., ATG13). The defect in ER-to-Golgi trafficking activated the UPR pathway in ULK-deficient cells; both processes were reversed upon expression of SEC16A with a phosphomimetic substitution. Thus, the regulation of ER-to-Golgi trafficking by ULK1/2 is essential for cellular homeostasis.
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Affiliation(s)
- Joung Hyuck Joo
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Bo Wang
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA.,Integrated Biomedical Sciences Program, the University of Tennessee Health Science Center, Memphis, TN, USA
| | - Elisa Frankel
- Department of Biomolecular Chemistry, University of Wisconsin-Madison Medical School, Madison, WI, USA
| | - Liang Ge
- Department of Molecular and Cellular Biology, University of California Berkeley, Berkeley, CA, USA
| | - Lu Xu
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Rekha Iyengar
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - XiuJie Li-Harms
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Christopher Wright
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Timothy I Shaw
- St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, TN, USA.,Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Tullia Lindsten
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Douglas R Green
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Junmin Peng
- St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, TN, USA.,Departments of Structural Biology and Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Linda M Hendershot
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Fusun Kilic
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Ji Ying Sze
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison Medical School, Madison, WI, USA
| | - Mondira Kundu
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA
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61
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Life Stage-Specific Cargo Receptors Facilitate Glycosylphosphatidylinositol-Anchored Surface Coat Protein Transport in Trypanosoma brucei. mSphere 2017; 2:mSphere00282-17. [PMID: 28713858 PMCID: PMC5506558 DOI: 10.1128/msphere.00282-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 06/24/2017] [Indexed: 11/20/2022] Open
Abstract
The critical virulence factor of bloodstream-form Trypanosoma brucei is the glycosylphosphatidylinositol (GPI)-anchored variant surface glycoprotein (VSG). Endoplasmic reticulum (ER) exit of VSG is GPI dependent and relies on a discrete subset of COPII machinery (TbSec23.2/TbSec24.1). In other systems, p24 transmembrane adaptor proteins selectively recruit GPI-anchored cargo into nascent COPII vesicles. Trypanosomes have eight putative p24s (TbERP1 to TbERP8) that are constitutively expressed at the mRNA level. However, only four TbERP proteins (TbERP1, -2, -3, and -8) are detectable in bloodstream-form parasites. All four colocalize to ER exit sites, are required for efficient GPI-dependent ER exit, and are interdependent for steady-state stability. These results suggest shared function as an oligomeric ER GPI-cargo receptor. This cohort also mediates rapid forward trafficking of the soluble lysosomal hydrolase TbCatL. Procyclic insect-stage trypanosomes have a distinct surface protein, procyclin, bearing a different GPI anchor structure. A separate cohort of TbERP proteins (TbERP1, -2, -4, and -8) are expressed in procyclic parasites and also function in GPI-dependent ER exit. Collectively, these results suggest developmentally regulated TbERP cohorts, likely in obligate assemblies, that may recognize stage-specific GPI anchors to facilitate GPI-cargo trafficking throughout the parasite life cycle. IMPORTANCE African trypanosomes are protozoan parasites that cause African sleeping sickness. Critical to the success of the parasite is the variant surface glycoprotein (VSG), which covers the parasite cell surface and which is essential for evasion of the host immune system. VSG is membrane bound by a glycolipid (GPI) anchor that is attached in the earliest compartment of the secretory pathway, the endoplasmic reticulum (ER). We have previously shown that the anchor acts as a positive forward trafficking signal for ER exit, implying a cognate receptor mechanism for GPI recognition and loading in coated cargo vesicles leaving the ER. Here, we characterize a family of small transmembrane proteins that act at adaptors for this process. This work adds to our understanding of general GPI function in eukaryotic cells and specifically in the synthesis and transport of the critical virulence factor of pathogenic African trypanosomes.
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62
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Lyu L, Wang B, Xiong C, Zhang X, Zhang X, Zhang J. Selective export of autotaxin from the endoplasmic reticulum. J Biol Chem 2017; 292:7011-7022. [PMID: 28298439 DOI: 10.1074/jbc.m116.774356] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 03/13/2017] [Indexed: 12/28/2022] Open
Abstract
Autotaxin (ATX) or ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2) is a secretory glycoprotein and functions as the key enzyme for lysophosphatidic acid generation. The mechanism of ATX protein trafficking is largely unknown. Here, we demonstrated that p23, a member of the p24 protein family, was the protein-sorting receptor required for endoplasmic reticulum (ER) export of ATX. A di-phenylalanine (Phe-838/Phe-839) motif in the human ATX C-terminal region was identified as a transport signal essential for the ATX-p23 interaction. Knockdown of individual Sec24 isoforms by siRNA revealed that ER export of ATX was impaired only if Sec24C was down-regulated. These results suggest that ATX is selectively exported from the ER through a p23, Sec24C-dependent pathway. In addition, it was found that AKT signaling played a role in ATX secretion regulation to facilitate ATX ER export by enhancing the nuclear factor of activated T cell-mediated p23 expression. Furthermore, the di-hydrophobic amino acid motifs (FY) also existed in the C-terminal regions of human ENPP1 and ENPP3. Such a p23, Sec24C-dependent selective ER export mechanism is conserved among these ENPP family members.
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Affiliation(s)
- Lin Lyu
- From the Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, Institute of Cell Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Baolu Wang
- From the Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, Institute of Cell Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Chaoyang Xiong
- From the Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, Institute of Cell Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Xiaotian Zhang
- From the Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, Institute of Cell Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Xiaoyan Zhang
- From the Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, Institute of Cell Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Junjie Zhang
- From the Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, Institute of Cell Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
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63
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Scharaw S, Iskar M, Ori A, Boncompain G, Laketa V, Poser I, Lundberg E, Perez F, Beck M, Bork P, Pepperkok R. The endosomal transcriptional regulator RNF11 integrates degradation and transport of EGFR. J Cell Biol 2016; 215:543-558. [PMID: 27872256 PMCID: PMC5119934 DOI: 10.1083/jcb.201601090] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 09/07/2016] [Accepted: 10/17/2016] [Indexed: 12/24/2022] Open
Abstract
Maintenance of EGFR plasma membrane levels is critical for cell functioning. Scharaw et al. demonstrate that endosomal RNF11 is required for transcriptional up-regulation of COPII components, specifically facilitating EGFR transport in response to its lysosomal degradation after EGF stimulation. Stimulation of cells with epidermal growth factor (EGF) induces internalization and partial degradation of the EGF receptor (EGFR) by the endo-lysosomal pathway. For continuous cell functioning, EGFR plasma membrane levels are maintained by transporting newly synthesized EGFRs to the cell surface. The regulation of this process is largely unknown. In this study, we find that EGF stimulation specifically increases the transport efficiency of newly synthesized EGFRs from the endoplasmic reticulum to the plasma membrane. This coincides with an up-regulation of the inner coat protein complex II (COPII) components SEC23B, SEC24B, and SEC24D, which we show to be specifically required for EGFR transport. Up-regulation of these COPII components requires the transcriptional regulator RNF11, which localizes to early endosomes and appears additionally in the cell nucleus upon continuous EGF stimulation. Collectively, our work identifies a new regulatory mechanism that integrates the degradation and transport of EGFR in order to maintain its physiological levels at the plasma membrane.
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Affiliation(s)
- Sandra Scharaw
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Murat Iskar
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Alessandro Ori
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Gaelle Boncompain
- Institut Curie, Paris Sciences et Lettres Research University, 75248 Paris, France.,Institut Curie, Centre National de la Recherche Scientifique UMR144, 75248 Paris, France
| | - Vibor Laketa
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Ina Poser
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Emma Lundberg
- Science for Life Laboratory, KTH Royal Institute of Technology, 17121 Solna, Sweden
| | - Franck Perez
- Institut Curie, Paris Sciences et Lettres Research University, 75248 Paris, France.,Institut Curie, Centre National de la Recherche Scientifique UMR144, 75248 Paris, France
| | - Martin Beck
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Peer Bork
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Max Delbrueck Center for Molecular Medicine, 13125 Berlin, Germany.,Department of Bioinformatics, Biocenter, University of Wuerzburg, 97074 Wuerzburg, Germany
| | - Rainer Pepperkok
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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64
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3D Structure and Interaction of p24β and p24δ Golgi Dynamics Domains: Implication for p24 Complex Formation and Cargo Transport. J Mol Biol 2016; 428:4087-4099. [DOI: 10.1016/j.jmb.2016.08.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 08/20/2016] [Accepted: 08/20/2016] [Indexed: 12/19/2022]
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65
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Martinez H, García IA, Sampieri L, Alvarez C. Spatial-Temporal Study of Rab1b Dynamics and Function at the ER-Golgi Interface. PLoS One 2016; 11:e0160838. [PMID: 27500526 PMCID: PMC4976911 DOI: 10.1371/journal.pone.0160838] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 07/26/2016] [Indexed: 12/27/2022] Open
Abstract
The GTPase Rab1b is involved in ER to Golgi transport, with multiple Rab1b effectors (located at ERES, VTCs and the Golgi complex) being required for its function. In this study, we performed live-cell dual-expression studies to analyze the dynamics of Rab1b and some effectors located at the ERES-Golgi interface. Rab1b occupied widely distributed mobile punctate and tubular structures, displaying a transient overlaps with its effectors and showing that these overlaps occurred at the same time in spatially distinct steps of ER to Golgi transport. In addition, we assessed Rab1b dynamics during cargo sorting by analyzing the concentration at ERES of a Golgi protein (SialT2-CFP) during Brefeldin A washout (BFA WO). Rab1b was associated to most of the ERES structures, but at different times during BFA WO, and recurrently SialT2-CFP was sorted in the ERES-Rab1b positive structures. Furthermore, we reveal for first time that Rab1b localization time at ERES depended on GBF1, a Rab1b effector that acts as the guanine nucleotide exchange factor of Arf1, and that Rab1b membrane association/dissociation dynamics at ERES was dependent on the GBF1 membrane association and activity, which strongly suggests that GBF1 activity modulates Rab1b membrane cycling dynamic.
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Affiliation(s)
- Hernán Martinez
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
| | - Iris A. García
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
| | - Luciana Sampieri
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
| | - Cecilia Alvarez
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
- * E-mail:
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66
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Adolf F, Rhiel M, Reckmann I, Wieland FT. Sec24C/D-isoform-specific sorting of the preassembled ER-Golgi Q-SNARE complex. Mol Biol Cell 2016; 27:2697-707. [PMID: 27413010 PMCID: PMC5007090 DOI: 10.1091/mbc.e16-04-0229] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 07/08/2016] [Indexed: 11/18/2022] Open
Abstract
SNAREs are incorporated into COPII vesicles by direct interaction with Sec24. In mammals, Sec24 isoforms recruit either Sec22b or the Q-SNARE complex comprising Syntaxin5, GS27, and Bet1. Analysis of immunoisolated COPII vesicles and intracellular localization of Sec24 isoforms indicates that all ER-Golgi SNAREs are present on the same vesicles. Secretory proteins are exported from the endoplasmic reticulum in COPII vesicles. SNARE proteins—core machinery for membrane fusion—are incorporated into COPII vesicles by direct interaction with Sec24. Here we report a novel mechanism for sorting of the ER–Golgi Q-SNAREs into COPII vesicles. Different mammalian Sec24 isoforms recruit either the R-SNARE Sec22b or the Q-SNAREs Syntaxin5, GS27, and Bet1. Syntaxin5 is the only Q-SNARE that directly interacts with Sec24C, requiring its “open” conformation. Mutation within the IxM cargo-binding site of Sec24C led to a drastic reduction in sorting of all three Q-SNAREs into COPII vesicles, implying their ER export as a preassembled complex. Analysis of immunoisolated COPII vesicles and intracellular localization of Sec24 isoforms indicate that all ER–Golgi SNAREs are present on the same vesicle. Combined with existing data, our findings yield a general concept of how Sec24 isoforms can recruit fusogenic SNARE subunits to keep them functionally apart and thus prime mammalian COPII vesicles for homotypic fusion.
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Affiliation(s)
- Frank Adolf
- Heidelberg University Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Manuel Rhiel
- Heidelberg University Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Ingeborg Reckmann
- Heidelberg University Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Felix T Wieland
- Heidelberg University Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
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67
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Pastor-Cantizano N, Montesinos JC, Bernat-Silvestre C, Marcote MJ, Aniento F. p24 family proteins: key players in the regulation of trafficking along the secretory pathway. PROTOPLASMA 2016; 253:967-985. [PMID: 26224213 DOI: 10.1007/s00709-015-0858-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 07/13/2015] [Indexed: 05/20/2023]
Abstract
p24 family proteins have been known for a long time, but their functions have remained elusive. However, they are emerging as essential regulators of protein trafficking along the secretory pathway, influencing the composition, structure, and function of different organelles in the pathway, especially the ER and the Golgi apparatus. In addition, they appear to modulate the transport of specific cargos, including GPI-anchored proteins, G-protein-coupled receptors, or K/HDEL ligands. As a consequence, they have been shown to play specific roles in signaling, development, insulin secretion, and the pathogenesis of Alzheimer's disease. The search of new putative ligands may open the way to discover new functions for this fascinating family of proteins.
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Affiliation(s)
- Noelia Pastor-Cantizano
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universitat de València, Avenida Vicente Andrés Estellés, s/n, E-46100, Burjassot, Valencia, Spain
| | - Juan Carlos Montesinos
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universitat de València, Avenida Vicente Andrés Estellés, s/n, E-46100, Burjassot, Valencia, Spain
| | - César Bernat-Silvestre
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universitat de València, Avenida Vicente Andrés Estellés, s/n, E-46100, Burjassot, Valencia, Spain
| | - María Jesús Marcote
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universitat de València, Avenida Vicente Andrés Estellés, s/n, E-46100, Burjassot, Valencia, Spain
| | - Fernando Aniento
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universitat de València, Avenida Vicente Andrés Estellés, s/n, E-46100, Burjassot, Valencia, Spain.
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68
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Abstract
Transport of newly synthesized proteins from the endoplasmic reticulum (ER) to the Golgi complex is highly selective. As a general rule, such transport is limited to soluble and membrane-associated secretory proteins that have reached properly folded and assembled conformations. To secure the efficiency, fidelity, and control of this crucial transport step, cells use a combination of mechanisms. The mechanisms are based on selective retention of proteins in the ER to prevent uptake into transport vesicles, on selective capture of proteins in COPII carrier vesicles, on inclusion of proteins in these vesicles by default as part of fluid and membrane bulk flow, and on selective retrieval of proteins from post-ER compartments by retrograde vesicle transport.
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Affiliation(s)
- Charles Barlowe
- Biochemistry Department, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755;
| | - Ari Helenius
- Institute of Biochemistry, ETH Zurich, Zurich CH-8093, Switzerland
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69
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Stadel D, Millarte V, Tillmann KD, Huber J, Tamin-Yecheskel BC, Akutsu M, Demishtein A, Ben-Zeev B, Anikster Y, Perez F, Dötsch V, Elazar Z, Rogov V, Farhan H, Behrends C. TECPR2 Cooperates with LC3C to Regulate COPII-Dependent ER Export. Mol Cell 2016; 60:89-104. [PMID: 26431026 DOI: 10.1016/j.molcel.2015.09.010] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/08/2015] [Accepted: 09/10/2015] [Indexed: 02/08/2023]
Abstract
Hereditary spastic paraplegias (HSPs) are a diverse group of neurodegenerative diseases that are characterized by axonopathy of the corticospinal motor neurons. A mutation in the gene encoding for Tectonin β-propeller containing protein 2 (TECPR2) causes HSP that is complicated by neurological symptoms. While TECPR2 is a human ATG8 binding protein and positive regulator of autophagy, the exact function of TECPR2 is unknown. Here, we show that TECPR2 associates with several trafficking components, among them the COPII coat protein SEC24D. TECPR2 is required for stabilization of SEC24D protein levels, maintenance of functional ER exit sites (ERES), and efficient ER export in a manner dependent on binding to lipidated LC3C. TECPR2-deficient HSP patient cells display alterations in SEC24D abundance and ER export efficiency. Additionally, TECPR2 and LC3C are required for autophagosome formation, possibly through maintaining functional ERES. Collectively, these results reveal that TECPR2 functions as molecular scaffold linking early secretion pathway and autophagy.
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Affiliation(s)
- Daniela Stadel
- Institute of Biochemistry II, Medical School Goethe University, 60590 Frankfurt, Germany
| | - Valentina Millarte
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany; Biotechnology Institute Thurgau, 8280 Kreuzlingen, Switzerland
| | - Kerstin D Tillmann
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany; Biotechnology Institute Thurgau, 8280 Kreuzlingen, Switzerland
| | - Jessica Huber
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | | | - Masato Akutsu
- Institute of Biochemistry II, Medical School Goethe University, 60590 Frankfurt, Germany; Buchmann Institute for Molecular Life Sciences, Goethe University, 60438 Frankfurt, Germany
| | - Alik Demishtein
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Bruria Ben-Zeev
- Edmond and Lilly Safra Children's Hospital, Sheba Medical Center, Ramat Gan, 52621, Israel; Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Yair Anikster
- Edmond and Lilly Safra Children's Hospital, Sheba Medical Center, Ramat Gan, 52621, Israel; Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Franck Perez
- Institute Curie, CNRS UMR144, Paris, 75248, France
| | - Volker Dötsch
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | - Zvulun Elazar
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Vladimir Rogov
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | - Hesso Farhan
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany; Biotechnology Institute Thurgau, 8280 Kreuzlingen, Switzerland
| | - Christian Behrends
- Institute of Biochemistry II, Medical School Goethe University, 60590 Frankfurt, Germany.
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70
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Kinoshita T, Fujita M. Biosynthesis of GPI-anchored proteins: special emphasis on GPI lipid remodeling. J Lipid Res 2015; 57:6-24. [PMID: 26563290 DOI: 10.1194/jlr.r063313] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Indexed: 02/06/2023] Open
Abstract
Glycosylphosphatidylinositols (GPIs) act as membrane anchors of many eukaryotic cell surface proteins. GPIs in various organisms have a common backbone consisting of ethanolamine phosphate (EtNP), three mannoses (Mans), one non-N-acetylated glucosamine, and inositol phospholipid, whose structure is EtNP-6Manα-2Manα-6Manα-4GlNα-6myoinositol-P-lipid. The lipid part is either phosphatidylinositol of diacyl or 1-alkyl-2-acyl form, or inositol phosphoceramide. GPIs are attached to proteins via an amide bond between the C-terminal carboxyl group and an amino group of EtNP. Fatty chains of inositol phospholipids are inserted into the outer leaflet of the plasma membrane. More than 150 different human proteins are GPI anchored, whose functions include enzymes, adhesion molecules, receptors, protease inhibitors, transcytotic transporters, and complement regulators. GPI modification imparts proteins with unique characteristics, such as association with membrane microdomains or rafts, transient homodimerization, release from the membrane by cleavage in the GPI moiety, and apical sorting in polarized cells. GPI anchoring is essential for mammalian embryogenesis, development, neurogenesis, fertilization, and immune system. Mutations in genes involved in remodeling of the GPI lipid moiety cause human diseases characterized by neurological abnormalities. Yeast Saccharomyces cerevisiae has >60 GPI-anchored proteins (GPI-APs). GPI is essential for growth of yeast. In this review, we discuss biosynthesis of GPI-APs in mammalian cells and yeast with emphasis on the lipid moiety.
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Affiliation(s)
- Taroh Kinoshita
- WPI Immunology Frontier Research Center and Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
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71
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Muñiz M, Riezman H. Trafficking of glycosylphosphatidylinositol anchored proteins from the endoplasmic reticulum to the cell surface. J Lipid Res 2015; 57:352-60. [PMID: 26450970 DOI: 10.1194/jlr.r062760] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Indexed: 11/20/2022] Open
Abstract
In eukaryotes, many cell surface proteins are attached to the plasma membrane via a glycolipid glycosylphosphatidylinositol (GPI) anchor. GPI-anchored proteins (GPI-APs) receive the GPI anchor as a conserved posttranslational modification in the lumen of the endoplasmic reticulum (ER). After anchor attachment, the GPI anchor is structurally remodeled to function as a transport signal that actively triggers the delivery of GPI-APs from the ER to the plasma membrane, via the Golgi apparatus. The structure and composition of the GPI anchor confer a special mode of interaction with membranes of GPI-APs within the lumen of secretory organelles that lead them to be differentially trafficked from other secretory membrane proteins. In this review, we examine the mechanisms by which GPI-APs are selectively transported through the secretory pathway, with special focus on the recent progress made in their actively regulated export from the ER and the trans-Golgi network.
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Affiliation(s)
- Manuel Muñiz
- Departamento de Biología Celular, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Howard Riezman
- National Centre of Competence in Research (NCCR) Chemical Biology, Department of Biochemistry, University of Geneva, Geneva, Switzerland
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72
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Saha S, Anilkumar AA, Mayor S. GPI-anchored protein organization and dynamics at the cell surface. J Lipid Res 2015; 57:159-75. [PMID: 26394904 DOI: 10.1194/jlr.r062885] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Indexed: 01/05/2023] Open
Abstract
The surface of eukaryotic cells is a multi-component fluid bilayer in which glycosylphosphatidylinositol (GPI)-anchored proteins are an abundant constituent. In this review, we discuss the complex nature of the organization and dynamics of GPI-anchored proteins at multiple spatial and temporal scales. Different biophysical techniques have been utilized for understanding this organization, including fluorescence correlation spectroscopy, fluorescence recovery after photobleaching, single particle tracking, and a number of super resolution methods. Major insights into the organization and dynamics have also come from exploring the short-range interactions of GPI-anchored proteins by fluorescence (or Förster) resonance energy transfer microscopy. Based on the nanometer to micron scale organization, at the microsecond to the second time scale dynamics, a picture of the membrane bilayer emerges where the lipid bilayer appears inextricably intertwined with the underlying dynamic cytoskeleton. These observations have prompted a revision of the current models of plasma membrane organization, and suggest an active actin-membrane composite.
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Affiliation(s)
- Suvrajit Saha
- National Centre for Biological Sciences (Tata Institute of Fundamental Research), Bangalore 560065, India
| | - Anupama Ambika Anilkumar
- National Centre for Biological Sciences (Tata Institute of Fundamental Research), Bangalore 560065, India Shanmugha Arts, Science, Technology and Research Academy, Thanjavur 613401, India
| | - Satyajit Mayor
- National Centre for Biological Sciences (Tata Institute of Fundamental Research), Bangalore 560065, India Institute for Stem Cell Biology and Regenerative Medicine (inStem), Bangalore 560065, India
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73
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Davis EM, Kim J, Menasche BL, Sheppard J, Liu X, Tan AC, Shen J. Comparative Haploid Genetic Screens Reveal Divergent Pathways in the Biogenesis and Trafficking of Glycophosphatidylinositol-Anchored Proteins. Cell Rep 2015; 11:1727-36. [PMID: 26074080 DOI: 10.1016/j.celrep.2015.05.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 04/17/2015] [Accepted: 05/11/2015] [Indexed: 11/30/2022] Open
Abstract
Glycophosphatidylinositol-anchored proteins (GPI-APs) play essential roles in physiology, but their biogenesis and trafficking have not been systematically characterized. Here, we took advantage of the recently available haploid genetics approach to dissect GPI-AP pathways in human cells using prion protein (PrP) and CD59 as model molecules. Our screens recovered a large number of common and unexpectedly specialized factors in the GPI-AP pathways. PIGN, PGAP2, and PIGF, which encode GPI anchor-modifying enzymes, were selectively isolated in the CD59 screen, suggesting that GPI anchor composition significantly influences the biogenesis of GPI-APs in a substrate-dependent manner. SEC62 and SEC63, which encode components of the ER-targeting machinery, were selectively recovered in the PrP screen, indicating that they do not constitute a universal route for the biogenesis of mammalian GPI-APs. Together, these comparative haploid genetic screens demonstrate that, despite their similarity in overall architecture and subcellular localization, GPI-APs follow markedly distinct biosynthetic and trafficking pathways.
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Affiliation(s)
- Eric M Davis
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Jihye Kim
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Bridget L Menasche
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Jacob Sheppard
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Xuedong Liu
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Aik-Choon Tan
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Jingshi Shen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA.
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74
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Iwasaki H, Yorimitsu T, Sato K. Distribution of Sec24 isoforms to each ER exit site is dynamically regulated in Saccharomyces cerevisiae. FEBS Lett 2015; 589:1234-9. [PMID: 25896017 DOI: 10.1016/j.febslet.2015.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 03/27/2015] [Accepted: 04/06/2015] [Indexed: 02/05/2023]
Abstract
COPII vesicles are formed at specific subdomains of the ER, termed ER exit sites (ERESs). Depending on the cell type, ERESs number from a few to several hundred per cell. However, whether these ERESs are functionally and compositionally identical at the cellular level remains unclear. Our live cell-imaging analysis in Saccharomyces cerevisiae revealed that the isoforms of cargo-adaptor subunits are unequally distributed to each ERES at steady state, whereas this distribution is altered in response to UPR activation. These results suggest that in S. cerevisiae cargo loading to ERES is dynamically controlled in response to environmental changes.
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Affiliation(s)
- Hirohiko Iwasaki
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Tomohiro Yorimitsu
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Ken Sato
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan.
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75
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Paladino S, Lebreton S, Zurzolo C. Trafficking and Membrane Organization of GPI-Anchored Proteins in Health and Diseases. CURRENT TOPICS IN MEMBRANES 2015; 75:269-303. [PMID: 26015286 DOI: 10.1016/bs.ctm.2015.03.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are a class of lipid-anchored proteins attached to the membranes by a glycolipid anchor that is added, as posttranslation modification, in the endoplasmic reticulum. GPI-APs are expressed at the cell surface of eukaryotes where they play diverse vital functions. Like all plasma membrane proteins, GPI-APs must be correctly sorted along the different steps of the secretory pathway to their final destination. The presence of both a glycolipid anchor and a protein portion confers special trafficking features to GPI-APs. Here, we discuss the recent advances in the field of GPI-AP trafficking, focusing on the mechanisms regulating their biosynthetic pathway and plasma membrane organization. We also discuss how alterations of these mechanisms can result in different diseases. Finally, we will examine the strict relationship between the trafficking and function of GPI-APs in epithelial cells.
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Affiliation(s)
- Simona Paladino
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università Federico II, Napoli, Italy; CEINGE Biotecnologie Avanzate, Napoli, Italy
| | - Stéphanie Lebreton
- Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, Paris, France
| | - Chiara Zurzolo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università Federico II, Napoli, Italy; Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, Paris, France
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76
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Satpute-Krishnan P, Ajinkya M, Bhat S, Itakura E, Hegde RS, Lippincott-Schwartz J. ER stress-induced clearance of misfolded GPI-anchored proteins via the secretory pathway. Cell 2015; 158:522-33. [PMID: 25083867 PMCID: PMC4121523 DOI: 10.1016/j.cell.2014.06.026] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 04/08/2014] [Accepted: 06/09/2014] [Indexed: 11/15/2022]
Abstract
Proteins destined for the cell surface are first assessed in the endoplasmic reticulum (ER) for proper folding before release into the secretory pathway. This ensures that defective proteins are normally prevented from entering the extracellular environment, where they could be disruptive. Here, we report that, when ER folding capacity is saturated during stress, misfolded glycosylphosphatidylinositol-anchored proteins dissociate from resident ER chaperones, engage export receptors, and quantitatively leave the ER via vesicular transport to the Golgi. Clearance from the ER commences within minutes of acute ER stress, before the transcriptional component of the unfolded protein response is activated. These aberrant proteins then access the cell surface transiently before destruction in lysosomes. Inhibiting this stress-induced pathway by depleting the ER-export receptors leads to aggregation of the ER-retained misfolded protein. Thus, this rapid response alleviates the elevated burden of misfolded proteins in the ER at the onset of ER stress, promoting protein homeostasis in the ER.
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Affiliation(s)
- Prasanna Satpute-Krishnan
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Monica Ajinkya
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Savithri Bhat
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Eisuke Itakura
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Ramanujan S Hegde
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
| | - Jennifer Lippincott-Schwartz
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA.
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77
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Jaensch N, Corrêa IR, Watanabe R. Stable cell surface expression of GPI-anchored proteins, but not intracellular transport, depends on their fatty acid structure. Traffic 2014; 15:1305-29. [PMID: 25196094 DOI: 10.1111/tra.12224] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 09/02/2014] [Accepted: 09/02/2014] [Indexed: 11/28/2022]
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are a class of lipid anchored proteins expressed on the cell surface of eukaryotes. The potential interaction of GPI-APs with ordered lipid domains enriched in cholesterol and sphingolipids has been proposed to function in the intracellular transport of these lipid anchored proteins. Here, we examined the biological importance of two saturated fatty acids present in the phosphatidylinositol moiety of GPI-APs. These fatty acids are introduced by the action of lipid remodeling enzymes and required for the GPI-AP association within ordered lipid domains. We found that the fatty acid remodeling is not required for either efficient Golgi-to-plasma membrane transport or selective endocytosis via GPI-enriched early endosomal compartment (GEEC)/ clathrin-independent carrier (CLIC) pathway, whereas cholesterol depletion significantly affects both pathways independent of their fatty acid structure. Therefore, the mechanism of cholesterol dependence does not appear to be related to the interaction with ordered lipid domains mediated by two saturated fatty acids. Furthermore, cholesterol extraction drastically releases the unremodeled GPI-APs carrying an unsaturated fatty acid from the cell surface, but not remodeled GPI-APs carrying two saturated fatty acids. This underscores the essential role of lipid remodeling to ensure a stable membrane association of GPI-APs particularly under potential membrane lipid perturbation.
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Affiliation(s)
- Nina Jaensch
- Department of Biochemistry, University of Geneva Sciences II, CH1-1211 Geneva, Switzerland
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78
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Marín-Buera L, García-Bartolomé A, Morán M, López-Bernardo E, Cadenas S, Hidalgo B, Sánchez R, Seneca S, Arenas J, Martín MA, Ugalde C. Differential proteomic profiling unveils new molecular mechanisms associated with mitochondrial complex III deficiency. J Proteomics 2014; 113:38-56. [PMID: 25239759 DOI: 10.1016/j.jprot.2014.09.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/31/2014] [Accepted: 09/09/2014] [Indexed: 12/27/2022]
Abstract
UNLABELLED We have analyzed the cellular pathways and metabolic adaptations that take place in primary skin fibroblasts from patients with mutations in BCS1L, a major genetic cause of mitochondrial complex III enzyme deficiency. Mutant fibroblasts exhibited low oxygen consumption rates and intracellular ATP levels, indicating that the main altered molecular event probably is a limited respiration-coupled ATP production through the OXPHOS system. Two-dimensional DIGE and MALDI-TOF/TOF mass spectrometry analyses unambiguously identified 39 proteins whose expression was significantly altered in complex III-deficient fibroblasts. Extensive statistical and cluster analyses revealed a protein profile characteristic for the BCS1L mutant fibroblasts that included alterations in energy metabolism, cell signaling and gene expression regulation, cytoskeleton formation and maintenance, and intracellular stress responses. The physiological validation of the predicted functional adaptations of human cultured fibroblasts to complex III deficiency confirmed the up-regulation of glycolytic enzyme activities and the accumulation of branched-chain among other amino acids, suggesting the activation of anaerobic glycolysis and cellular catabolic states, in particular protein catabolism, together with autophagy as adaptive responses to mitochondrial respiratory chain dysfunction and ATP deficiency. Our data point to an overall metabolic and genetic reprogramming that could contribute to explain the clinical manifestations of complex III deficiency in patients. BIOLOGICAL SIGNIFICANCE Despite considerable knowledge about their genetic origins, the pathophysiological mechanisms that contribute to the clinical manifestations of mitochondrial disorders remain poorly understood. We have investigated the molecular pathways and metabolic adaptations that take place in primary skin fibroblasts from patients with mutations in the BCS1L gene, a primary cause of mitochondrial complex III enzyme deficiency. Two-dimensional DIGE together with MALDI-TOF/TOF mass spectrometry and physiological validation analyses revealed a significant metabolic and genetic reprogramming as an adaptive response to mitochondrial respiratory chain dysfunction. Our data provide information about specific protein targets that regulate the transmitochondrial functional responses to complex III deficiency, thereby opening new doors for future research.
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Affiliation(s)
- Lorena Marín-Buera
- Instituto de Investigación, Hospital Universitario 12 de Octubre, Madrid 28041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), U723, Madrid, Spain
| | - Alberto García-Bartolomé
- Instituto de Investigación, Hospital Universitario 12 de Octubre, Madrid 28041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), U723, Madrid, Spain
| | - María Morán
- Instituto de Investigación, Hospital Universitario 12 de Octubre, Madrid 28041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), U723, Madrid, Spain
| | - Elia López-Bernardo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM) and Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain.,Servicio de Inmunología, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa (IP), 28006 Madrid, Spain
| | - Susana Cadenas
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM) and Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain.,Servicio de Inmunología, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa (IP), 28006 Madrid, Spain
| | - Beatriz Hidalgo
- Servicio de Bioquímica, Hospital Universitario 12 de Octubre, Madrid 28041, Spain
| | - Ricardo Sánchez
- Servicio de Bioquímica, Hospital Universitario 12 de Octubre, Madrid 28041, Spain
| | - Sara Seneca
- Center of Medical Genetics, AZ-VUB, Brussels, Belgium
| | - Joaquín Arenas
- Instituto de Investigación, Hospital Universitario 12 de Octubre, Madrid 28041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), U723, Madrid, Spain
| | - Miguel A Martín
- Instituto de Investigación, Hospital Universitario 12 de Octubre, Madrid 28041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), U723, Madrid, Spain
| | - Cristina Ugalde
- Instituto de Investigación, Hospital Universitario 12 de Octubre, Madrid 28041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), U723, Madrid, Spain
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79
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Hauser JT, Lindner R. Coalescence of B cell receptor and invariant chain MHC II in a raft-like membrane domain. J Leukoc Biol 2014; 96:843-55. [PMID: 25024398 DOI: 10.1189/jlb.2a0713-353r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The BCR binds antigen for processing and subsequent presentation on MHC II molecules. Polyvalent antigen induces BCR clustering and targeting to endocytic processing compartments, which are also accessed by Ii-MHC II. Here, we report that clustered BCR is able to team up with Ii-MHC II already at the plasma membrane of mouse B-lymphocytes. Colocalization of BCR and Ii-MHC II on the cell surface required clustering of both types of molecules. The clustering of only one type did not trigger the recruitment of the other. Ii-bound MIF (a ligand of Ii) also colocalized with clustered BCR upon oligomerization of MIF on the surface of the B cell. Abundant surface molecules, such as B220 or TfnR, did not cocluster with the BCR. Some membrane raft-associated molecules, such as peptide-loaded MHC II, coclustered with the BCR, whereas others, such as GM1, did not. The formation of a BCR- and Ii-MHC II-containing membrane domain by antibody-mediated clustering was independent of F-actin and led to the coendocytosis of its constituents. With a rapid Brij 98 extraction method, it was possible to capture this membrane domain biochemically as a DRM. Ii and clustered BCR were present on the same DRM, as shown by immunoisolation. The coalescence of BCR and Ii-MHC II increased tyrosine phosphorylation, indicative of enhanced BCR signaling. Our work suggests a novel role for MIF and Ii-MHC II in BCR-mediated antigen processing.
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Affiliation(s)
- Julian T Hauser
- Hannover Medical School, Department of Cell Biology, Center for Anatomy, Hannover, Germany
| | - Robert Lindner
- Hannover Medical School, Department of Cell Biology, Center for Anatomy, Hannover, Germany
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80
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Helm JR, Bentley M, Thorsen KD, Wang T, Foltz L, Oorschot V, Klumperman J, Hay JC. Apoptosis-linked gene-2 (ALG-2)/Sec31 interactions regulate endoplasmic reticulum (ER)-to-Golgi transport: a potential effector pathway for luminal calcium. J Biol Chem 2014; 289:23609-28. [PMID: 25006245 DOI: 10.1074/jbc.m114.561829] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Luminal calcium released from secretory organelles has been suggested to play a regulatory role in vesicle transport at several steps in the secretory pathway; however, its functional roles and effector pathways have not been elucidated. Here we demonstrate for the first time that specific luminal calcium depletion leads to a significant decrease in endoplasmic reticulum (ER)-to-Golgi transport rates in intact cells. Ultrastructural analysis revealed that luminal calcium depletion is accompanied by increased accumulation of intermediate compartment proteins in COPII buds and clusters of unfused COPII vesicles at ER exit sites. Furthermore, we present several lines of evidence suggesting that luminal calcium affected transport at least in part through calcium-dependent interactions between apoptosis-linked gene-2 (ALG-2) and the Sec31A proline-rich region: 1) targeted disruption of ALG-2/Sec31A interactions caused severe defects in ER-to-Golgi transport in intact cells; 2) effects of luminal calcium and ALG-2/Sec31A interactions on transport mutually required each other; and 3) Sec31A function in transport required luminal calcium. Morphological phenotypes of disrupted ALG-2/Sec31A interactions were characterized. We found that ALG-2/Sec31A interactions were not required for the localization of Sec31A to ER exit sites per se but appeared to acutely regulate the stability and trafficking of the cargo receptor p24 and the distribution of the vesicle tether protein p115. These results represent the first outline of a mechanism that connects luminal calcium to specific protein interactions regulating vesicle trafficking machinery.
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Affiliation(s)
- Jared R Helm
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
| | - Marvin Bentley
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
| | - Kevin D Thorsen
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
| | - Ting Wang
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
| | - Lauren Foltz
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
| | - Viola Oorschot
- the Cell Microscopy Center, Department of Cell Biology, University Medical Center Utrecht, AZU Room H02.313, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Judith Klumperman
- the Cell Microscopy Center, Department of Cell Biology, University Medical Center Utrecht, AZU Room H02.313, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Jesse C Hay
- From the Division of Biological Sciences and Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59812-4824 and
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81
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Axonal targeting of the serotonin transporter in cultured rat dorsal raphe neurons is specified by SEC24C-dependent export from the endoplasmic reticulum. J Neurosci 2014; 34:6344-6351. [PMID: 24790205 DOI: 10.1523/jneurosci.2991-13.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Export of the serotonin transporter (SERT) from the endoplasmic reticulum (ER) is mediated by the SEC24C isoform of the coatomer protein-II complex. SERT must enter the axonal compartment and reach the presynaptic specialization to perform its function, i.e., the inward transport of serotonin. Refilling of vesicles is contingent on the operation of an efficient relay between SERT and the vesicular monoamine transporter-2 (VMAT2). Here, we visualized the distribution of both endogenously expressed SERT and heterologously expressed variants of human SERT in dissociated rat dorsal raphe neurons to examine the role of SEC24C-dependent ER export in axonal targeting of SERT. We conclude that axonal delivery of SERT is contingent on recruitment of SEC24C in the ER. This conclusion is based on the following observations. (1) Both endogenous and heterologously expressed SERT were delivered to the extensive axonal arborizations and accumulated in bouton-like structures. (2) In contrast, SERT-(607)RI(608)-AA, in which the binding site of SEC24C is disrupted, remained confined to the microtubule-associated protein 2-positive somatodendritic compartment. (3) The overexpression of dominant-negative SEC24C-D(796)V/D(797)N (but not of the corresponding SEC24D mutant) redirected both endogenous SERT and heterologously expressed yellow fluorescent protein-SERT from axons to the somatodendritic region. (4) SERT-K(610)Y, which harbors a mutation converting it into an SEC24D client, was rerouted from the axonal to the somatodendritic compartment by dominant-negative SEC24D. In contrast, axonal targeting of the VMAT2 was disrupted by neither dominant-negative SEC24C nor dominant-negative SEC24D. This suggests that SERT and VMAT2 reach the presynaptic specialization by independent routes.
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82
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Muñiz M, Zurzolo C. Sorting of GPI-anchored proteins from yeast to mammals--common pathways at different sites? J Cell Sci 2014; 127:2793-801. [PMID: 24906797 DOI: 10.1242/jcs.148056] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are luminal secretory cargos that are attached by a post-translational glycolipid modification, the GPI anchor, to the external leaflet of the plasma membrane. GPI-APs are conserved among eukaryotes and possess many diverse and vital functions for which the GPI membrane attachment appears to be essential. The presence of the GPI anchor and its subsequent modifications along the secretory pathway confer to the anchored proteins unique trafficking properties that make GPI-APs an exceptional system to study mechanisms of sorting. In this Commentary, we discuss the recent advances in the field of GPI-AP sorting focusing on the mechanisms operating at the level of the exit from the ER and from the trans-Golgi network (TGN), which take place, respectively, in yeast and in polarized mammalian cells. By considering the similarities and differences between these two sorting events, we present unifying principles that appear to work at different sorting stations and in different organisms.
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Affiliation(s)
- Manuel Muñiz
- Department of Cell Biology, University of Seville, Avda. Reina Mercedes s/n 41012 Seville, Spain
| | - Chiara Zurzolo
- Institut Pasteur, Unité de Trafic Membranaire et Pathogénèse, 75724 Paris CEDEX 15, France
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83
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Yang X, Zhang Y, Zhang L, He T, Zhang J, Li C. Prion protein and cancers. Acta Biochim Biophys Sin (Shanghai) 2014; 46:431-40. [PMID: 24681883 DOI: 10.1093/abbs/gmu019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The normal cellular prion protein, PrP(C) is a highly conserved and widely expressed cell surface glycoprotein in all mammals. The expression of PrP is pivotal in the pathogenesis of prion diseases; however, the normal physiological functions of PrP(C) remain incompletely understood. Based on the studies in cell models, a plethora of functions have been attributed to PrP(C). In this paper, we reviewed the potential roles that PrP(C) plays in cell physiology and focused on its contribution to tumorigenesis.
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Affiliation(s)
- Xiaowen Yang
- Department of the First Abdominal Surgery, Jiangxi Tumor Hospital, Nanchang 330029, China
| | - Yan Zhang
- Department of Molecular Endocrinology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Lihua Zhang
- Department of Pathology, Zhongda Hospital, Southeast University, Nanjing 210009, China
| | - Tianlin He
- Department of General Surgery, Changhai Hospital of Second Military Medical University, Shanghai 200433, China
| | - Jie Zhang
- Department of Stomatology, The First Affiliated Hospital of Shihezi University Medical College, Shihezi 832000, China
| | - Chaoyang Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
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84
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Fossati M, Goud B, Borgese N, Manneville JB. An investigation of the effect of membrane curvature on transmembrane-domain dependent protein sorting in lipid bilayers. CELLULAR LOGISTICS 2014; 4:e29087. [PMID: 25210649 PMCID: PMC4156485 DOI: 10.4161/cl.29087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 04/21/2014] [Accepted: 04/30/2014] [Indexed: 01/08/2023]
Abstract
Sorting of membrane proteins within the secretory pathway of eukaryotic cells is a complex process involving discrete sorting signals as well as physico-chemical properties of the transmembrane domain (TMD). Previous work demonstrated that tail-anchored (TA) protein sorting at the interface between the Endoplasmic Reticulum (ER) and the Golgi complex is exquisitely dependent on the length and hydrophobicity of the transmembrane domain, and suggested that an imbalance between TMD length and bilayer thickness (hydrophobic mismatch) could drive long TMD-containing proteins into curved membrane domains, including ER exit sites, with consequent export of the mismatched protein out of the ER. Here, we tested a possible role of curvature in TMD-dependent sorting in a model system consisting of Giant Unilamellar Vesicles (GUVs) from which narrow membrane tubes were pulled by micromanipulation. Fluorescent TA proteins differing in TMD length were incorporated into GUVs of uniform lipid composition or made of total ER lipids, and TMD-dependent sorting and diffusion, as well as the bending rigidity of bilayers made of microsomal lipids, were investigated. Long and short TMD-containing constructs were inserted with similar orientation, diffused equally rapidly in GUVs and in tubes pulled from GUVs, and no difference in their final distribution between planar and curved regions was detected. These results indicate that curvature alone is not sufficient to drive TMD-dependent sorting at the ER-Golgi interface, and set the basis for the investigation of the additional factors that must be required.
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Affiliation(s)
- Matteo Fossati
- CNR Institute of Neuroscience and Department of Biotechnology and Translational Medicine; University of Milano; Milano, Italy
| | - Bruno Goud
- CNRS-Institut Curie; UMR144; Paris, France
| | - Nica Borgese
- CNR Institute of Neuroscience and Department of Biotechnology and Translational Medicine; University of Milano; Milano, Italy ; Department of Health Science; University of Catanzaro "Magna Graecia"; Catanzaro, Italy
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85
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Theiler R, Fujita M, Nagae M, Yamaguchi Y, Maeda Y, Kinoshita T. The α-helical region in p24γ2 subunit of p24 protein cargo receptor is pivotal for the recognition and transport of glycosylphosphatidylinositol-anchored proteins. J Biol Chem 2014; 289:16835-43. [PMID: 24778190 DOI: 10.1074/jbc.m114.568311] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are group of proteins that depend on p24 cargo receptors for their transport from the endoplasmic reticulum to the Golgi apparatus. The GPI anchor is expected to act as a sorting and transport signal, but so far little is known about the recognition mechanism. In the present study we investigate the GPI-AP transport in cell knockdown of p24γ, the most diverse p24 subfamily. Knockdown of p24γ2 but not of other p24γ family members impaired the transport of a reporter GPI-AP. Restoration of the knockdown-induced phenotype using chimeric constructs between p24γ2 and the related p24γ1 further implied a role of the α-helical region of p24γ2 but not its GOLD domain in the specific binding of GPI-APs. We conclude that motifs in the membrane-adjacent α-helical region of p24γ2 are involved in recognition of GPI-APs and are consequently responsible for the incorporation of these proteins into coat protein complex II-coated transport vesicles.
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Affiliation(s)
- Romina Theiler
- From the World Premier International (WPI) Immunology Frontier Research Center and Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan and
| | - Morihisa Fujita
- From the World Premier International (WPI) Immunology Frontier Research Center and Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan and
| | - Masamichi Nagae
- the Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yoshiki Yamaguchi
- the Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yusuke Maeda
- From the World Premier International (WPI) Immunology Frontier Research Center and Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan and
| | - Taroh Kinoshita
- From the World Premier International (WPI) Immunology Frontier Research Center and Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan and
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87
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Hirata R, Nihei CI, Nakano A. Isoform-selective oligomer formation of Saccharomyces cerevisiae p24 family proteins. J Biol Chem 2013; 288:37057-70. [PMID: 24217251 DOI: 10.1074/jbc.m113.518340] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
p24 family proteins are evolutionarily conserved transmembrane proteins involved in the early secretory pathway. Saccharomyces cerevisiae has 8 known p24 proteins that are classified into four subfamilies (p24α, -β, -γ, and -δ). Emp24 and Erv25 are the sole members of p24β and -δ, respectively, and deletion of either destabilizes the remaining p24 proteins, resulting in p24 null phenotype (p24Δ). We studied genetic and physical interactions of p24α (Erp1, -5, and -6) and γ (Erp2, -3, and -4). Deletion of the major p24α (Erp1) partially inhibited p24 activity as reported previously. A second mutation in either Erp5 or Erp6 aggravated the erp1Δ phenotype, and the triple mutation gave a full p24Δ phenotype. Similar genetic interactions were observed among the major p24γ (Erp2) and the other two γ members. All the p24α/γ isoforms interacted with both p24β and -δ. Interaction between p24β and -δ was isoform-selective, and five major α/γ pairs were detected. These results suggest that the yeast p24 proteins form functionally redundant αβγδ complexes. We also identified Rrt6 as a novel p24δ isoform. Rrt6 shows only limited sequence identity (∼15%) to known p24 proteins but was found to have structural properties characteristic of p24. Rrt6 was induced when cells were grown on glycerol and form an additional αβγδ complex with Erp3, Erp5, and Emp24. This complex was mainly localized to the Golgi, whereas the p24 complex containing Erv25, instead of Rrt6 but otherwise with the same isoform composition, was found mostly in the ER.
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Affiliation(s)
- Ryogo Hirata
- From the Live Cell Molecular Imaging Research Team, RIKEN Center for Advanced Photonics and
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88
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Guizzunti G, Zurzolo C. The fate of PrP GPI-anchor signal peptide is modulated by P238S pathogenic mutation. Traffic 2013; 15:78-93. [PMID: 24112521 DOI: 10.1111/tra.12126] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Revised: 09/24/2013] [Accepted: 10/01/2013] [Indexed: 12/30/2022]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins are localized to the plasma membrane via a C-terminally linked GPI anchor. The GPI anchor is added concomitantly to the cleavage of the carboxy-terminal GPI-anchor signal sequence, thereby causing the release of a C-terminal hydrophobic peptide, whose fate has not yet been investigated. Here we followed the fate of the GPI-attachment signal of the prion protein (PrP), a protein implicated in various types of transmissible neurodegenerative spongiform encephalopathies (TSE). The PrP GPI-anchor signal sequence shows a remarkable and unusual degree of conservation across the species and contains two point mutations (M232R/T and P238S) that are responsible for genetic forms of prion disorders. We show that the PrP GPI-anchor signal peptide (SP), but not the one from an unrelated GPI-anchored protein (folate receptor), undergoes degradation via the proteasome. Moreover, the P238S point mutation partially protects the PrP GPI-anchor SP from degradation. Our data provide the first attempt to address the fate of a GPI-anchor SP and identify a role for the P238S mutation, suggesting the possibility that the PrP GPI-anchor SP could play a role in neurodegenerative prion diseases.
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Affiliation(s)
- Gianni Guizzunti
- Institut Pasteur, Unité de Trafic Membranaire et Pathogenèse, 25-28 rue du Docteur Roux, 75015, Paris, France
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89
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Ronquist GK, Ek B, Ronquist G, Morrell J, Carlsson L, Larsson A. Biochemical characterization of stallion prostasomes and comparison to their human counterparts. Syst Biol Reprod Med 2013; 59:297-303. [DOI: 10.3109/19396368.2013.822612] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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90
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Significance of folate receptor alpha and thymidylate synthase protein expression in patients with non-small-cell lung cancer treated with pemetrexed. J Thorac Oncol 2013; 8:19-30. [PMID: 23242435 DOI: 10.1097/jto.0b013e31827628ff] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Folate receptor alpha (FRA) regulates cellular uptake of folates and antifolates. Information about FRA protein expression in metastatic non-small-cell lung cancer (NSCLC) is limited. We investigated FRA as a biomarker for pemetrexed-based chemotherapy and compared it with thymidylate synthase (TS), the main target of pemetrexed. METHODS Pretreatment tumor specimens from 207 patients with advanced NSCLC were assessed for FRA and TS protein expression by immunohistochemistry using the H-score (range, 0-300) and correlated to patients' clinicopathological data, radiographic response, progression-free survival (PFS), and overall survival (OS). RESULTS Low total (cytoplasmic and nuclear) TS protein expression (H-score < 210) was associated with improved PFS (median: 5.6 versus 3.5 months; hazard ratio [HR] = 0.6379, p = 0.0131) and prolonged OS (median: 22.5 versus 11.5 months; HR = 0.5680,p = 0.0107). An association between lower TS levels and response to pemetrexed-based therapy was found-mean H-score 187 ± 5, median 180 for responders versus mean H-score 201 ± 4, median 210, for non-responders, p = 0.0244. High intracellular FRA expression (H-score ≥110) was associated with prolonged OS (28.9 versus 11.7 months, HR = 0.5316, p = 0.0040) and a trend for association with PFS (5.6 versus 4.1 months, HR = 0.7395, p = 0.0801) was noted. Membranous FRA expression was seen in 83% of patients, moreover, high membranous expression (H-score ≥20) was associated with improved PFS (5.6 versus 3.7 months, HR = 0.6445, p = 0.0306) and OS (22.1 versus 11.5 months, HR = 0.5378, p = 0.0131). CONCLUSIONS A large number of NSCLC patients have high expression of FRA and/or a low level of TS expression. Expression levels of FRA and TS were associated with clinical benefit from pemetrexed therapy.
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91
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Kinoshita T, Maeda Y, Fujita M. Transport of glycosylphosphatidylinositol-anchored proteins from the endoplasmic reticulum. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2473-8. [PMID: 23380706 DOI: 10.1016/j.bbamcr.2013.01.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 01/15/2013] [Accepted: 01/25/2013] [Indexed: 12/17/2022]
Abstract
In this review on the transport of glycosylphosphatidylinositol-anchored proteins (GPI-APs), we focus on events that occur in the endoplasmic reticulum after the transfer of GPI to proteins. These events include structural remodeling of both the lipid and glycan moieties of GPI, recruitment of GPI-APs into ER exit sites, association with the cargo receptor, p24 protein complex, and packaging into COPII coated transport vesicles. Similarities with the transport of Wnt proteins are also discussed. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum.
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92
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Lester HA, Miwa JM, Srinivasan R. Psychiatric drugs bind to classical targets within early exocytotic pathways: therapeutic effects. Biol Psychiatry 2012; 72:907-15. [PMID: 22771239 PMCID: PMC6167061 DOI: 10.1016/j.biopsych.2012.05.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 04/23/2012] [Accepted: 05/21/2012] [Indexed: 11/17/2022]
Abstract
The classical targets for antipsychotic and antidepressant drugs are G protein-coupled receptors and neurotransmitter transporters, respectively. Full therapeutic actions of these drugs require several weeks. We show how therapeutic effects may eventually accrue after existing therapeutic ligands bind to these classical targets, not on the plasma membrane but rather within endoplasmic reticulum (ER) and cis-Golgi. Consequences of such binding may include pharmacological chaperoning: the nascent drug targets are stabilized against degradation and can therefore exit the ER more readily. Another effect may be matchmaking: heterodimers and homodimers of the target form and can more readily exit the ER. Summarizing recent data for nicotinic receptors, we explain how such effects could lead to reduced ER stress and to a decreased unfolded protein response, including changes in gene activation and protein synthesis. In effects not directly related to cellular stress, escorting would allow increased ER exit and trafficking of known associated proteins, as well as other proteins such as growth factors and their receptors, producing both cell-autonomous and non-cell-autonomous effects. Axonal transport of relevant proteins may underlie the several weeks required for full therapy. In contrast, the antidepressant effects of ketamine and other N-methyl-D-aspartate receptor ligands, which occur within <2 hours, could arise from dendritically localized intracellular binding, followed by chaperoning, matchmaking, escorting, and reduced ER stress. Thus, the effects of intracellular binding extend beyond proteostasis of the targets themselves and involve pathways distinct from ion channel and G protein activation. We propose experimental tests and note pathophysiological correlates.
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Affiliation(s)
- Henry A Lester
- Division of Biology, California Institute of Technology, Pasadena, California.
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93
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Miwa JM, Walz A. Enhancement in motor learning through genetic manipulation of the Lynx1 gene. PLoS One 2012; 7:e43302. [PMID: 23139735 PMCID: PMC3489911 DOI: 10.1371/journal.pone.0043302] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 07/18/2012] [Indexed: 11/18/2022] Open
Abstract
The cholinergic system is a neuromodulatory neurotransmitter system involved in a variety of brain processes, including learning and memory, attention, and motor processes, among others. The influence of nicotinic acetylcholine receptors of the cholinergic system are moderated by lynx proteins, which are GPI-anchored membrane proteins forming tight associations with nicotinic receptors. Previous studies indicate lynx1 inhibits nicotinic receptor function and limits neuronal plasticity. We sought to investigate the mechanism of action of lynx1 on nicotinic receptor function, through the generation of lynx mouse models, expressing a soluble version of lynx and comparing results to the full length overexpression. Using rotarod as a test for motor learning, we found that expressing a secreted variant of lynx leads to motor learning enhancements whereas overexpression of full-length lynx had no effect. Further, adult lynx1KO mice demonstrated comparable motor learning enhancements as the soluble transgenic lines, whereas previously, aged lynx1KO mice showed performance augmentation only with nicotine treatment. From this we conclude the motor learning is more sensitive to loss of lynx function, and that the GPI anchor plays a role in the normal function of the lynx protein. In addition, our data suggests that the lynx gene plays a modulatory role in the brain during aging, and that a soluble version of lynx has potential as a tool for adjusting cholinergic-dependent plasticity and learning mechanisms in the brain.
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Affiliation(s)
- Julie M Miwa
- California Institute of Technology, Pasadena, California, USA.
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94
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Ejaz A, Steinmann E, Bánki Z, Anggakusuma, Khalid S, Lengauer S, Wilhelm C, Zoller H, Schloegl A, Steinmann J, Grabski E, Kleines M, Pietschmann T, Stoiber H. Specific acquisition of functional CD59 but not CD46 or CD55 by hepatitis C virus. PLoS One 2012; 7:e45770. [PMID: 23049856 PMCID: PMC3458075 DOI: 10.1371/journal.pone.0045770] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 08/22/2012] [Indexed: 01/07/2023] Open
Abstract
Viruses of different families encode for regulators of the complement system (RCAs) or acquire such RCAs from the host to get protection against complement-mediated lysis (CML). As hepatitis C virus (HCV) shares no genetic similarity to any known RCA and is detectable at high titers in sera of infected individuals, we investigated whether HCV has adapted host-derived RCAs to resist CML. Here we report that HCV selectively incorporates CD59 while neither CD55, nor CD46 are associated with the virus. The presence of CD59 was shown by capture assays using patient- and cell culture-derived HCV isolates. Association of CD59 with HCV was further confirmed by Western blot analysis using purified viral supernatants from infected Huh 7.5 cells. HCV captured by antibodies specific for CD59 remained infectious for Huh 7.5 cells. In addition, blocking of CD59 in the presence of active complement reduced the titer of HCV most likely due to CML. HCV produced in CD59 knock-down cells were more significantly susceptible to CML compared to wild type virus, but neither replication, assembly nor infectivity of the virus seemed to be impaired in the absence of CD59. In summary our data indicate that HCV incorporates selectively CD59 in its envelope to gain resistance to CML in serum of infected individuals.
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Affiliation(s)
- Asim Ejaz
- Institute of Virology, Innsbruck Medical University, Innsbruck, Austria
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95
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Chapuis J, Vingtdeux V, Capiralla H, Davies P, Marambaud P. Gas1 interferes with AβPP trafficking by facilitating the accumulation of immature AβPP in endoplasmic reticulum-associated raft subdomains. J Alzheimers Dis 2012; 28:127-35. [PMID: 21971401 DOI: 10.3233/jad-2011-110434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The amyloid-β protein precursor (AβPP) is a type I transmembrane protein that undergoes maturation during trafficking in the secretory pathway. Proper maturation and trafficking of AβPP are necessary prerequisites for AβPP processing to generate amyloid-β (Aβ), the core component of Alzheimer's disease senile plaques. Recently, we reported that the glycosylphosphatidylinositol (GPI)-anchored protein growth arrest-specific 1 (Gas1) binds to and interferes with the maturation and processing of AβPP. Gas1 expression led to a trafficking blockade of AβPP between the endoplasmic reticulum (ER) and the Golgi. GPI-anchored proteins can exit the ER by transiting through raft subdomains acting as specialized sorting platforms. Here, we show that Gas1 co-partitioned and formed a complex with AβPP in raft fractions, wherein Gas1 overexpression triggered immature AβPP accumulation. Pharmacological interference of ER to Golgi transport increased immature AβPP accumulation upon Gas1 expression in these raft fractions, which were found to be positive for the COPII protein complex component Sec31A, a specific marker for ER exit sites. Furthermore, a Gas1 mutant lacking the GPI anchor that could not transit through rafts was still able to form a complex with AβPP but did not lead to immature AβPP accumulation in rafts. Together these data show that Gas1 interfered with AβPP trafficking by interacting with AβPP to facilitate its translocation into specialized ER-associated rafts where immature AβPP accumulated.
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Affiliation(s)
- Julien Chapuis
- Litwin-Zucker Research Center for the Study of Alzheimer's Disease, The Feinstein Institute for Medical Research, Manhasset, NY 11030, USA
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96
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Fujita M, Kinoshita T. GPI-anchor remodeling: Potential functions of GPI-anchors in intracellular trafficking and membrane dynamics. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1050-8. [DOI: 10.1016/j.bbalip.2012.01.004] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 12/28/2011] [Accepted: 01/04/2012] [Indexed: 01/08/2023]
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97
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Cánepa GE, Mesías AC, Yu H, Chen X, Buscaglia CA. Structural features affecting trafficking, processing, and secretion of Trypanosoma cruzi mucins. J Biol Chem 2012; 287:26365-76. [PMID: 22707724 DOI: 10.1074/jbc.m112.354696] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Trypanosoma cruzi is wrapped by a dense coat of mucin-type molecules encoded by complex gene families termed TcSMUG and TcMUC, which are expressed in the insect- and mammal-dwelling forms of the parasite, respectively. Here, we dissect the contribution of distinct post-translational modifications on the trafficking of these glycoconjugates. In vivo tracing and characterization of tagged-variants expressed by transfected epimastigotes indicate that although the N-terminal signal peptide is responsible for targeting TcSMUG products to the endoplasmic reticulum (ER), the glycosyl phosphatidylinositol (GPI)-anchor likely functions as a forward transport signal for their timely progression along the secretory pathway. GPI-minus variants accumulate in the ER, with only a minor fraction being ultimately released to the medium as anchorless products. Secreted products, but not ER-accumulated ones, display several diagnostic features of mature mucin-type molecules including extensive O-type glycosylation, Galf-based epitopes recognized by monoclonal antibodies, and terminal Galp residues that become readily sialylated upon addition of parasite trans-sialidases. Processing of N-glycosylation site(s) is dispensable for the overall TcSMUG mucin-type maturation and secretion. Despite undergoing different O-glycosylation elaboration, TcMUC reporters yielded quite similar results, thus indicating that (i) molecular trafficking signals are structurally and functionally conserved between mucin families, and (ii) TcMUC and TcSMUG products are recognized and processed by a distinct repertoire of stage-specific glycosyltransferases. Thus, using the fidelity of a homologous expression system, we have defined some biosynthetic aspects of T. cruzi mucins, key molecules involved in parasite protection and virulence.
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Affiliation(s)
- Gaspar E Cánepa
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo Ugalde," Av. 25 de Mayo y Francia, Campus UNSAM, San Martín 1650, Buenos Aires, Argentina
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98
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Domon M, Nasir MN, Matar G, Pikula S, Besson F, Bandorowicz-Pikula J. Annexins as organizers of cholesterol- and sphingomyelin-enriched membrane microdomains in Niemann-Pick type C disease. Cell Mol Life Sci 2012; 69:1773-85. [PMID: 22159585 PMCID: PMC11114673 DOI: 10.1007/s00018-011-0894-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 11/17/2011] [Accepted: 11/21/2011] [Indexed: 01/22/2023]
Abstract
Growing evidence suggests that membrane microdomains enriched in cholesterol and sphingomyelin are sites for numerous cellular processes, including signaling, vesicular transport, interaction with pathogens, and viral infection, etc. Recently some members of the annexin family of conserved calcium and membrane-binding proteins have been recognized as cholesterol-interacting molecules and suggested to play a role in the formation, stabilization, and dynamics of membrane microdomains to affect membrane lateral organization and to attract other proteins and signaling molecules onto their territory. Furthermore, annexins were implicated in the interactions between cytosolic and membrane molecules, in the turnover and storage of cholesterol and in various signaling pathways. In this review, we focus on the mechanisms of interaction of annexins with lipid microdomains and the role of annexins in membrane microdomains dynamics including possible participation of the domain-associated forms of annexins in the etiology of human lysosomal storage disease called Niemann-Pick type C disease, related to the abnormal storage of cholesterol in the lysosome-like intracellular compartment. The involvement of annexins and cholesterol/sphingomyelin-enriched membrane microdomains in other pathologies including cardiac dysfunctions, neurodegenerative diseases, obesity, diabetes mellitus, and cancer is likely, but is not supported by substantial experimental observations, and therefore awaits further clarification.
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Affiliation(s)
- Magdalena Domon
- Laboratory of Lipid Biochemistry, Department of Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093, Warsaw, Poland
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99
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Loizides-Mangold U, David FPA, Nesatyy VJ, Kinoshita T, Riezman H. Glycosylphosphatidylinositol anchors regulate glycosphingolipid levels. J Lipid Res 2012; 53:1522-34. [PMID: 22628614 DOI: 10.1194/jlr.m025692] [Citation(s) in RCA: 199] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glycosylphosphatidylinositol (GPI) anchor biosynthesis takes place in the endoplasmic reticulum (ER). After protein attachment, the GPI anchor is transported to the Golgi where it undergoes fatty acid remodeling. The ER exit of GPI-anchored proteins is controlled by glycan remodeling and p24 complexes act as cargo receptors for GPI anchor sorting into COPII vesicles. In this study, we have characterized the lipid profile of mammalian cell lines that have a defect in GPI anchor biosynthesis. Depending on which step of GPI anchor biosynthesis the cells were defective, we observed sphingolipid changes predominantly for very long chain monoglycosylated ceramides (HexCer). We found that the structure of the GPI anchor plays an important role in the control of HexCer levels. GPI anchor-deficient cells that generate short truncated GPI anchor intermediates showed a decrease in very long chain HexCer levels. Cells that synthesize GPI anchors but have a defect in GPI anchor remodeling in the ER have a general increase in HexCer levels. GPI-transamidase-deficient cells that produce no GPI-anchored proteins but generate complete free GPI anchors had unchanged levels of HexCer. In contrast, sphingomyelin levels were mostly unaffected. We therefore propose a model in which the transport of very long chain ceramide from the ER to Golgi is regulated by the transport of GPI anchor molecules.
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Affiliation(s)
- Ursula Loizides-Mangold
- Department of Biochemistry, NCCR Chemical Biology, University of Geneva, CH-1211 Geneva, Switzerland
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100
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Sugawara T, Nakatsu D, Kii H, Maiya N, Adachi A, Yamamoto A, Kano F, Murata M. PKCδ and ε regulate the morphological integrity of the ER–Golgi intermediate compartment (ERGIC) but not the anterograde and retrograde transports via the Golgi apparatus. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:861-75. [DOI: 10.1016/j.bbamcr.2012.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 01/13/2012] [Accepted: 01/17/2012] [Indexed: 02/03/2023]
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