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Lujan P, Garcia-Cabau C, Wakana Y, Vera Lillo J, Rodilla-Ramírez C, Sugiura H, Malhotra V, Salvatella X, Garcia-Parajo MF, Campelo F. Sorting of secretory proteins at the trans-Golgi network by human TGN46. eLife 2024; 12:RP91708. [PMID: 38466628 DOI: 10.7554/elife.91708] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024] Open
Abstract
Secretory proteins are sorted at the trans-Golgi network (TGN) for export into specific transport carriers. However, the molecular players involved in this fundamental process remain largely elusive. Here, we identified the human transmembrane protein TGN46 as a receptor for the export of secretory cargo protein PAUF in CARTS - a class of protein kinase D-dependent TGN-to-plasma membrane carriers. We show that TGN46 is necessary for cargo sorting and loading into nascent carriers at the TGN. By combining quantitative fluorescence microscopy and mutagenesis approaches, we further discovered that the lumenal domain of TGN46 encodes for its cargo sorting function. In summary, our results define a cellular function of TGN46 in sorting secretory proteins for export from the TGN.
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Affiliation(s)
- Pablo Lujan
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Carla Garcia-Cabau
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Yuichi Wakana
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Javier Vera Lillo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Carmen Rodilla-Ramírez
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Hideaki Sugiura
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Vivek Malhotra
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Xavier Salvatella
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Maria F Garcia-Parajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Felix Campelo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Barcelona, Spain
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2
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Sbornova I, van der Sande E, Milosavljevic S, Amurrio E, Burbano SD, Das PK, Do HH, Fisher JL, Kargbo P, Patel J, Porcher L, De Zeeuw CI, Meester-Smoor MA, Winkelman BHJ, Klaver CCW, Pocivavsek A, Kelly MP. The Sleep Quality- and Myopia-Linked PDE11A-Y727C Variant Impacts Neural Physiology by Reducing Catalytic Activity and Altering Subcellular Compartmentalization of the Enzyme. Cells 2023; 12:2839. [PMID: 38132157 PMCID: PMC10742168 DOI: 10.3390/cells12242839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023] Open
Abstract
Recently, a Y727C variant in the dual-specific 3',5'-cyclic nucleotide phosphodiesterase 11A (PDE11A-Y727C) was linked to increased sleep quality and reduced myopia risk in humans. Given the well-established role that the PDE11 substrates cAMP and cGMP play in eye physiology and sleep, we determined if (1) PDE11A protein is expressed in the retina or other eye segments in mice, (2) PDE11A-Y7272C affects catalytic activity and/or subcellular compartmentalization more so than the nearby suicide-associated PDE11A-M878V variant, and (3) Pde11a deletion alters eye growth or sleep quality in male and female mice. Western blots show distinct protein expression of PDE11A4, but not PDE11A1-3, in eyes of Pde11a WT, but not KO mice, that vary by eye segment and age. In HT22 and COS-1 cells, PDE11A4-Y727C reduces PDE11A4 catalytic activity far more than PDE11A4-M878V, with both variants reducing PDE11A4-cAMP more so than PDE11A4-cGMP activity. Despite this, Pde11a deletion does not alter age-related changes in retinal or lens thickness or axial length, nor vitreous or anterior chamber depth. Further, Pde11a deletion only minimally changes refractive error and sleep quality. That said, both variants also dramatically alter the subcellular compartmentalization of human and mouse PDE11A4, an effect occurring independently of dephosphorylating PDE11A4-S117/S124 or phosphorylating PDE11A4-S162. Rather, re-compartmentalization of PDE11A4-Y727C is due to the loss of the tyrosine changing how PDE11A4 is packaged/repackaged via the trans-Golgi network. Therefore, the protective impact of the Y727C variant may reflect a gain-of-function (e.g., PDE11A4 displacing another PDE) that warrants further investigation in the context of reversing/preventing sleep disturbances or myopia.
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Affiliation(s)
- Irina Sbornova
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St., Baltimore, MD 21201, USA (P.K.D.); (J.P.)
| | - Emilie van der Sande
- Department of Ophthalmology, Erasmus Medical Center, Wytemaweg 40, 3015 CN Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Wytemaweg 40, 3015 CN Rotterdam, The Netherlands
- The Netherlands Institute for Neuroscience (NIN), Royal Dutch Academy of Art & Science (KNAW), Meibergdreef 47, 1105 AZ Amsterdam, The Netherlands
| | - Snezana Milosavljevic
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Garners Ferry Rd., Columbia, SC 29209, USA
| | - Elvis Amurrio
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St., Baltimore, MD 21201, USA (P.K.D.); (J.P.)
| | - Steven D. Burbano
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St., Baltimore, MD 21201, USA (P.K.D.); (J.P.)
| | - Prosun K. Das
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St., Baltimore, MD 21201, USA (P.K.D.); (J.P.)
| | - Helen H. Do
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St., Baltimore, MD 21201, USA (P.K.D.); (J.P.)
| | - Janet L. Fisher
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Garners Ferry Rd., Columbia, SC 29209, USA
| | - Porschderek Kargbo
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St., Baltimore, MD 21201, USA (P.K.D.); (J.P.)
| | - Janvi Patel
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St., Baltimore, MD 21201, USA (P.K.D.); (J.P.)
| | - Latarsha Porcher
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St., Baltimore, MD 21201, USA (P.K.D.); (J.P.)
| | - Chris I. De Zeeuw
- The Netherlands Institute for Neuroscience (NIN), Royal Dutch Academy of Art & Science (KNAW), Meibergdreef 47, 1105 AZ Amsterdam, The Netherlands
- Department of Neuroscience, Erasmus Medical Center, Wytemaweg 40, 3015 CN Rotterdam, The Netherlands
| | - Magda A. Meester-Smoor
- Department of Ophthalmology, Erasmus Medical Center, Wytemaweg 40, 3015 CN Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Wytemaweg 40, 3015 CN Rotterdam, The Netherlands
| | - Beerend H. J. Winkelman
- Department of Ophthalmology, Erasmus Medical Center, Wytemaweg 40, 3015 CN Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Wytemaweg 40, 3015 CN Rotterdam, The Netherlands
- The Netherlands Institute for Neuroscience (NIN), Royal Dutch Academy of Art & Science (KNAW), Meibergdreef 47, 1105 AZ Amsterdam, The Netherlands
- Department of Neuroscience, Erasmus Medical Center, Wytemaweg 40, 3015 CN Rotterdam, The Netherlands
| | - Caroline C. W. Klaver
- Department of Ophthalmology, Erasmus Medical Center, Wytemaweg 40, 3015 CN Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Wytemaweg 40, 3015 CN Rotterdam, The Netherlands
- Department of Ophthalmology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
- Institute of Molecular and Clinical Ophthalmology, Mittlere Strasse 91, 4070 Basel, Switzerland
| | - Ana Pocivavsek
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Garners Ferry Rd., Columbia, SC 29209, USA
| | - Michy P. Kelly
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St., Baltimore, MD 21201, USA (P.K.D.); (J.P.)
- Center for Research on Aging, University of Maryland School of Medicine, 20 Penn St., Baltimore, MD 21201, USA
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3
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Sbornova I, van der Sande E, Milosavljevic S, Amurrio E, Burbano SD, Das P, Do H, Fisher JL, Kargbo P, Patel J, Porcher L, De Zeeuw CI, Meester-Smoor MA, Winkelman BH, Klaver CC, Pocivavsek A, Kelly MP. The sleep quality- and myopia-linked PDE11A-Y727C variant impacts neural physiology by reducing catalytic activity and altering subcellular compartmentalization of the enzyme. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.16.567422. [PMID: 38014312 PMCID: PMC10680747 DOI: 10.1101/2023.11.16.567422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Recently, a Y727C variant in the dual-specific 3',5'-cyclic nucleotide phosphodiesterase 11A (PDE11A-Y727C) was linked to increased sleep quality and reduced myopia risk in humans. Given the well-established role that the PDE11 substrates cAMP and cGMP play in eye physiology and sleep, we determined if 1) PDE11A protein is expressed in the retina or other eye segments in mouse, 2) PDE11A-Y7272C affects catalytic activity and/or subcellular compartmentalization more so than the nearby suicide-associated PDE11A-M878V variant, and 3) Pde11a deletion alters eye growth or sleep quality in male and female mice. Western blots show distinct protein expression of PDE11A4, but not PDE11A1-3, in eyes of Pde11a WT-but not KO mice-that vary by eye segment and age. In HT22 and COS-1 cells, PDE11A4-Y727C reduces PDE11A4 catalytic activity far more than PDE11A4-M878V, with both variants reducing PDE11A4-cAMP more so than PDE11A4-cGMP activity. Despite this, Pde11a deletion does not alter age-related changes in retinal or lens thickness, axial length, nor vitreous or anterior chamber depth. Further, Pde11a deletion only minimally changes refractive error and sleep quality. That said, both variants also dramatically alter the subcellular compartmentalization of human and mouse PDE11A4, an effect occurring independently of dephosphorylating PDE11A4-S117/S124 or phosphorylating PDE11A4-S162. Rather, re-compartmentalization of PDE11A4-Y727C is due to the loss of the tyrosine changing how PDE11A4 is packaged/repackaged via the trans-Golgi network. Therefore, the protective impact of the Y727C variant may reflect a gain-of-function (e.g., PDE11A4 displacing another PDE) that warrants further investigation in the context of reversing/preventing sleep disturbances or myopia.
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Affiliation(s)
- Irina Sbornova
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St, Baltimore, MD 21201
| | - Emilie van der Sande
- Department of Ophthalmology, Erasmus Medical Center, Wytemaweg 40, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Wytemaweg 40, Rotterdam, The Netherlands
- The Netherlands Institute for Neuroscience (NIN), Royal Dutch Academy of Art & Science (KNAW), Meibergdreef 47, Amsterdam, The Netherlands
| | - Snezana Milosavljevic
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Garners Ferry Rd, Columbia, SC
| | - Elvis Amurrio
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St, Baltimore, MD 21201
| | - Steven D. Burbano
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St, Baltimore, MD 21201
| | - Prosun Das
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St, Baltimore, MD 21201
| | - Helen Do
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St, Baltimore, MD 21201
| | - Janet L. Fisher
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Garners Ferry Rd, Columbia, SC
| | - Porschderek Kargbo
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St, Baltimore, MD 21201
| | - Janvi Patel
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St, Baltimore, MD 21201
| | - Latarsha Porcher
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St, Baltimore, MD 21201
| | - Chris I. De Zeeuw
- The Netherlands Institute for Neuroscience (NIN), Royal Dutch Academy of Art & Science (KNAW), Meibergdreef 47, Amsterdam, The Netherlands
- Department of Neuroscience, Erasmus Medical Center, Wytemaweg 40, Rotterdam, The Netherlands
| | - Magda A Meester-Smoor
- Department of Ophthalmology, Erasmus Medical Center, Wytemaweg 40, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Wytemaweg 40, Rotterdam, The Netherlands
| | - Beerend H.J. Winkelman
- Department of Ophthalmology, Erasmus Medical Center, Wytemaweg 40, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Wytemaweg 40, Rotterdam, The Netherlands
- The Netherlands Institute for Neuroscience (NIN), Royal Dutch Academy of Art & Science (KNAW), Meibergdreef 47, Amsterdam, The Netherlands
- Department of Neuroscience, Erasmus Medical Center, Wytemaweg 40, Rotterdam, The Netherlands
| | - Caroline C.W. Klaver
- Department of Ophthalmology, Erasmus Medical Center, Wytemaweg 40, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Wytemaweg 40, Rotterdam, The Netherlands
- Department of Ophthalmology, Radboud University Medical Center, Geert Grooteplein Zuid 10, Nijmegen, The Netherlands
- Institute of Molecular and Clinical Ophthalmology, Mittlere Strasse 91, Basel, Switzerland
| | - Ana Pocivavsek
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Garners Ferry Rd, Columbia, SC
| | - Michy P. Kelly
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 Penn St, Baltimore, MD 21201
- Center for Research on Aging, University of Maryland School of Medicine, 20 Penn St, Baltimore, MD 21201
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4
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Malik U, Zafar S, Younas N, Zerr I, Javed A. Unveiling the Physical and Functional Niches of FAM26F by Analyzing Its Subcellular Localization and Novel Interacting Partners. ACS OMEGA 2020; 5:22008-22020. [PMID: 32923759 PMCID: PMC7482079 DOI: 10.1021/acsomega.0c01249] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
The knowledge of a protein's subcellular localization and interacting partners are crucial for elucidating its cellular function and associated regulatory networks. Although FAM26F (family with sequence similarity 26, member F) has been recognized as a vital player in various infections, stimulation studies, cancer, and immune pathogenesis, the precise location and function of FAM26F are not well understood. The current study is the first to focus on functional characterization of FAM26F by analyzing its subcellular localization and identifying its novel interacting partners using advanced proteome approaches. The immunofluorescence and confocal microscopy results revealed FAM26F to be largely localized within the Golgi apparatus of the cell. However, its minor presence in endoplasmic reticulum (ER) pointed toward the probable retrograde transfer of FAM26F from Golgi to ER during adverse conditions. Moreover, co-immunoprecipitation and MS/MS results demonstrated a total of 85 proteins, 44 of which significantly copurified with FAM26F. Interestingly, out of these 44 MS/MS identified proteins, almost 52% were involved in innate immunity, 38.6% in neutrophil degranulation, and remaining 10% were either involved in phosphorylation, degradation, or regulation of apoptosis. Further characterization through Ingenuity Pathway Analysis showed that majority of these proteins was involved in maintaining calcium homeostasis of cell. Consequently, the validation of selected proteins uncovered the key interaction of FAM26F with Thioredoxin, which essentially paved the way for depicting its mechanism of action under stress or disease conditions. It is proposed that activation and inhibition of the cellular immune response is essentially dependent on whether FAM26F or Thioredoxin considerably interact with CD30R.
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Affiliation(s)
- Uzma Malik
- Department
of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences
(ASAB), National University of Sciences
and Technology (NUST), H-12 Campus, 44000 Islamabad, Pakistan
- Department
of Neurology, University Medical Centre Göttingen (UMG), Georg-August-Universität Göttingen, 37075 Göttingen, Germany
| | - Saima Zafar
- Department
of Neurology, University Medical Centre Göttingen (UMG), Georg-August-Universität Göttingen, 37075 Göttingen, Germany
- Department
of Biomedical Engineering & Sciences, School of Mechanical &
Manufacturing Engineering (SMME), National
University of Sciences and Technology (NUST), H-12
Campus, 44000 Islamabad, Pakistan
| | - Neelam Younas
- Department
of Neurology, University Medical Centre Göttingen (UMG), Georg-August-Universität Göttingen, 37075 Göttingen, Germany
| | - Inga Zerr
- Department
of Neurology, University Medical Centre Göttingen (UMG), Georg-August-Universität Göttingen, 37075 Göttingen, Germany
| | - Aneela Javed
- Department
of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences
(ASAB), National University of Sciences
and Technology (NUST), H-12 Campus, 44000 Islamabad, Pakistan
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5
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Loef EJ, Brooks AES, Lorenz N, Birch NP, Dunbar PR. Neuroserpin regulates human T cell-T cell interactions and proliferation through inhibition of tissue plasminogen activator. J Leukoc Biol 2020; 107:145-158. [PMID: 31667914 DOI: 10.1002/jlb.2a1019-098rr] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 10/07/2019] [Accepted: 10/14/2019] [Indexed: 01/01/2023] Open
Abstract
T cells play a key role in mounting an adaptive immune response. T cells are activated upon recognition of cognate Ag presented by an APC. Subsequently, T cells adhere to other activated T cells to form activation clusters, which lead to directed secretion of cytokines between communicating cells. T cell activation clusters have been implicated in regulating activation, proliferation, and memory formation in T cells. We previously reported the expression of the protease inhibitor neuroserpin by human T cells and showed that expression and intracellular localization is regulated following T cell activation. To gain a better understanding of neuroserpin in the proteolytic environment postactivation we assessed its role in human T cell clustering and proliferation. Neuroserpin knockdown increased T cell proliferation and cluster formation following T cell activation. This increased cluster formation was dependent on the proteases tissue plasminogen activator (tPA) and plasmin. Furthermore, neuroserpin knockdown or plasmin treatment of T cells increased the cleavage of annexin A2, a known plasmin target that regulates the actin cytoskeleton. Live cell imaging of activated T cells further indicated a role of the actin cytoskeleton in T cell clustering. The inhibition of actin regulators myosin ATPase and Rho-associated protein kinase signaling completely reversed the neuroserpin knockdown-induced effects. The results presented in this study reveal a novel role for neuroserpin and the proteolytic environment in the regulation of T cell activation biology.
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Affiliation(s)
- Evert Jan Loef
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Anna E S Brooks
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Natalie Lorenz
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
- School of Medical Sciences, The University of Auckland, Auckland, New Zealand
| | - Nigel P Birch
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- Centre for Brain Research and Brain Research New Zealand, The University of Auckland, Auckland, New Zealand
| | - P Rod Dunbar
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
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6
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Matsudaira T, Niki T, Taguchi T, Arai H. Transport of the cholera toxin B-subunit from recycling endosomes to the Golgi requires clathrin and AP-1. J Cell Sci 2015; 128:3131-42. [PMID: 26136365 DOI: 10.1242/jcs.172171] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 06/22/2015] [Indexed: 11/20/2022] Open
Abstract
The retrograde pathway is defined by the transport of proteins and lipids from the plasma membrane through endosomes to the Golgi complex, and is essential for a variety of cellular activities. Recycling endosomes are important sorting stations for some retrograde cargo. SMAP2, a GTPase-activating protein (GAP) for Arf1 with a putative clathrin-binding domain, has previously been shown to participate in the retrograde transport of the cholera toxin B-subunit (CTxB) from recycling endosomes. Here, we found that clathrin, a vesicle coat protein, and clathrin adaptor protein complex 1 (AP-1) were present at recycling endosomes and were needed for the retrograde transport of CTxB from recycling endosomes to the Golgi, but not from the plasma membrane to recycling endosomes. SMAP2 immunoprecipitated clathrin and AP-1 through a putative clathrin-binding domain and a CALM-binding domain, and SMAP2 mutants that did not interact with clathrin or AP-1 could not localize to recycling endosomes. Moreover, knockdown of Arf1 suppressed the retrograde transport of CTxB from recycling endosomes to the Golgi. These findings suggest that retrograde transport is mediated by clathrin-coated vesicles from recycling endosomes and that the role of the coat proteins is in the recruitment of Arf GAP to transport vesicles.
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Affiliation(s)
- Tatsuyuki Matsudaira
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takahiro Niki
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tomohiko Taguchi
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan Pathological Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan Pathological Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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7
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Kato S, Chen J, Cornog KH, Zhang H, Roberts JD. The Golgi apparatus regulates cGMP-dependent protein kinase I compartmentation and proteolysis. Am J Physiol Cell Physiol 2015; 308:C944-58. [PMID: 25855081 DOI: 10.1152/ajpcell.00199.2014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 03/31/2015] [Indexed: 01/12/2023]
Abstract
cGMP-dependent protein kinase I (PKGI) is an important effector of cGMP signaling that regulates vascular smooth muscle cell (SMC) phenotype and proliferation. PKGI has been detected in the perinuclear region of cells, and recent data indicate that proprotein convertases (PCs) typically resident in the Golgi apparatus (GA) can stimulate PKGI proteolysis and generate a kinase fragment that localizes to the nucleus and regulates gene expression. However, the role of the endomembrane system in PKGI compartmentation and processing is unknown. Here, we demonstrate that PKGI colocalizes with endoplasmic reticulum (ER), ER-Golgi intermediate compartment, GA cisterna, and trans-Golgi network proteins in pulmonary artery SMC and cell lines. Moreover, PKGI localizes with furin, a trans-Golgi network-resident PC known to cleave PKGI. ER protein transport influences PKGI localization because overexpression of a constitutively inactive Sar1 transgene caused PKGI retention in the ER. Additionally, PKGI appears to reside within the GA because PKGI immunoreactivity was determined to be resistant to cytosolic proteinase K treatment in live cells. The GA appears to play a role in PKGI proteolysis because overexpression of inositol 1,4,5-trisphosphate receptor-associated cGMP kinase substrate, not only tethered heterologous PKGI-β to the ER and decreased its localization to the GA, but also diminished PKGI proteolysis and nuclear translocation. Also, inhibiting intra-GA protein transport with monensin was observed to decrease PKGI cleavage. These studies detail a role for the endomembrane system in regulating PKGI compartmentation and proteolysis. Moreover, they support the investigation of mechanisms regulating PKGI-dependent nuclear cGMP signaling in the pulmonary vasculature with Golgi dysfunction.
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Affiliation(s)
- Shin Kato
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts
| | - Jingsi Chen
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts
| | | | - Huili Zhang
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts
| | - Jesse D Roberts
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts; Departments of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts; Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts; Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts; Department of Pediatrics, Harvard Medical School, Cambridge, Massachusetts;
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8
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Kebede MA, Oler AT, Gregg T, Balloon AJ, Johnson A, Mitok K, Rabaglia M, Schueler K, Stapleton D, Thorstenson C, Wrighton L, Floyd BJ, Richards O, Raines S, Eliceiri K, Seidah NG, Rhodes C, Keller MP, Coon JL, Audhya A, Attie AD. SORCS1 is necessary for normal insulin secretory granule biogenesis in metabolically stressed β cells. J Clin Invest 2014; 124:4240-56. [PMID: 25157818 DOI: 10.1172/jci74072] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 07/14/2014] [Indexed: 01/21/2023] Open
Abstract
We previously positionally cloned Sorcs1 as a diabetes quantitative trait locus. Sorcs1 belongs to the Vacuolar protein sorting-10 (Vps10) gene family. In yeast, Vps10 transports enzymes from the trans-Golgi network (TGN) to the vacuole. Whole-body Sorcs1 KO mice, when made obese with the leptin(ob) mutation (ob/ob), developed diabetes. β Cells from these mice had a severe deficiency of secretory granules (SGs) and insulin. Interestingly, a single secretagogue challenge failed to consistently elicit an insulin secretory dysfunction. However, multiple challenges of the Sorcs1 KO ob/ob islets consistently revealed an insulin secretion defect. The luminal domain of SORCS1 (Lum-Sorcs1), when expressed in a β cell line, acted as a dominant-negative, leading to SG and insulin deficiency. Using syncollin-dsRed5TIMER adenovirus, we found that the loss of Sorcs1 function greatly impairs the rapid replenishment of SGs following secretagogue challenge. Chronic exposure of islets from lean Sorcs1 KO mice to high glucose and palmitate depleted insulin content and evoked an insulin secretion defect. Thus, in metabolically stressed mice, Sorcs1 is important for SG replenishment, and under chronic challenge by insulin secretagogues, loss of Sorcs1 leads to diabetes. Overexpression of full-length SORCS1 led to a 2-fold increase in SG content, suggesting that SORCS1 is sufficient to promote SG biogenesis.
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9
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Matsudaira T, Uchida Y, Tanabe K, Kon S, Watanabe T, Taguchi T, Arai H. SMAP2 regulates retrograde transport from recycling endosomes to the Golgi. PLoS One 2013; 8:e69145. [PMID: 23861959 PMCID: PMC3704519 DOI: 10.1371/journal.pone.0069145] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 06/03/2013] [Indexed: 02/04/2023] Open
Abstract
Retrograde transport is where proteins and lipids are transported back from the plasma membrane (PM) and endosomes to the Golgi, and crucial for a diverse range of cellular functions. Recycling endosomes (REs) serve as a sorting station for the retrograde transport and we recently identified evection-2, an RE protein with a pleckstrin homology (PH) domain, as an essential factor of this pathway. How evection-2 regulates retrograde transport from REs to the Golgi is not well understood. Here, we report that evection-2 binds to SMAP2, an Arf GTPase-activating protein. Endogenous SMAP2 localized mostly in REs and to a lesser extent, the trans-Golgi network (TGN). SMAP2 binds evection-2, and the RE localization of SMAP2 was abolished in cells depleted of evection-2. Knockdown of SMAP2, like that of evection-2, impaired the retrograde transport of cholera toxin B subunit (CTxB) from REs. These findings suggest that evection-2 recruits SMAP2 to REs, thereby regulating the retrograde transport of CTxB from REs to the Golgi.
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Affiliation(s)
- Tatsuyuki Matsudaira
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Yasunori Uchida
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Kenji Tanabe
- Medical Research Institute, Tokyo Women’s Medical University, Tokyo, Japan
| | - Shunsuke Kon
- Department of Molecular Immunology, Institute of Development, Aging and Cancer, Tohoku University, Sendai-shi, Miyagi, Japan
| | - Toshio Watanabe
- Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women’s University, Nara-shi, Nara, Japan
| | - Tomohiko Taguchi
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
- Pathological Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
- * E-mail: (TT) (HA)
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
- Pathological Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
- * E-mail: (TT) (HA)
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10
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Abstract
Cells internalize extracellular solutes, ligands and proteins and lipids in the plasma membrane (PM) by endocytosis. The removal of membrane from the PM is counteracted by endosomal recycling pathways that return the endocytosed proteins and lipids back to the PM. Recycling to the PM can occur from early endosomes. However, many cells have a distinct subpopulation of endosomes that have a mildly acidic pH of 6.5 and are involved in the endosomal recycling. These endosomes are dubbed recycling endosomes (REs). In recent years, studies have begun to reveal that function of REs is not limited to the endosomal recycling. In this review, I summarize the nature of membrane trafficking pathways that pass through REs and the cell biological roles of these pathways.
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Affiliation(s)
- Tomohiko Taguchi
- Laboratory of Pathological Cell Biology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
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11
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Abstract
This article focuses on drug targeting to specific cellular organelles for therapeutic purposes. Drugs can be delivered to all major organelles of the cell (cytosol, endosome/lysosome, nucleus, nucleolus, mitochondria, endoplasmic reticulum, Golgi apparatus, peroxisomes and proteasomes) where they exert specific effects in those particular subcellular compartments. Delivery can be achieved by chemical (e.g., polymeric) or biological (e.g., signal sequences) means. Unidirectional targeting to individual organelles has proven to be immensely successful for drug therapy. Newer technologies that accommodate multiple signals (e.g., protein switch and virus-like delivery systems) mimic nature and allow for a more sophisticated approach to drug delivery. Harnessing different methods of targeting multiple organelles in a cell will lead to better drug delivery and improvements in disease therapy.
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12
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Pavelka M, Neumüller J, Ellinger A. Retrograde traffic in the biosynthetic-secretory route. Histochem Cell Biol 2008; 129:277-88. [PMID: 18270728 PMCID: PMC2248610 DOI: 10.1007/s00418-008-0383-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2008] [Indexed: 02/04/2023]
Abstract
In the biosynthetic-secretory route from the rough endoplasmic reticulum, across the pre-Golgi intermediate compartments, the Golgi apparatus stacks, trans Golgi network, and post-Golgi organelles, anterograde transport is accompanied and counterbalanced by retrograde traffic of both membranes and contents. In the physiologic dynamics of cells, retrograde flow is necessary for retrieval of molecules that escaped from their compartments of function, for keeping the compartments' balances, and maintenance of the functional integrities of organelles and compartments along the secretory route, for repeated use of molecules, and molecule repair. Internalized molecules may be transported in retrograde direction along certain sections of the secretory route, and compartments and machineries of the secretory pathway may be misused by toxins. An important example is the toxin of Shigella dysenteriae, which has been shown to travel from the cell surface across endosomes, and the Golgi apparatus en route to the endoplasmic reticulum, and the cytosol, where it exerts its deleterious effects. Most importantly in medical research, knowledge about the retrograde cellular pathways is increasingly being utilized for the development of strategies for targeted delivery of drugs to the interior of cells. Multiple details about the molecular transport machineries involved in retrograde traffic are known; a high number of the molecular constituents have been characterized, and the complicated fine structural architectures of the compartments involved become more and more visible. However, multiple contradictions exist, and already established traffic models again are in question by contradictory results obtained with diverse cell systems, and/or different techniques. Additional problems arise by the fact that the conditions used in the experimental protocols frequently do not reflect the physiologic situations of the cells. Regular and pathologic situations often are intermingled, and experimental treatments by themselves change cell organizations. This review addresses physiologic and pathologic situations, tries to correlate results obtained by different cell biologic techniques, and asks questions, which may be the basis and starting point for further investigations.
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Affiliation(s)
- Margit Pavelka
- Department of Cell Biology and Ultrastructure Research, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, Austria.
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13
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Lieu ZZ, Derby MC, Teasdale RD, Hart C, Gunn P, Gleeson PA. The golgin GCC88 is required for efficient retrograde transport of cargo from the early endosomes to the trans-Golgi network. Mol Biol Cell 2007; 18:4979-91. [PMID: 17914056 PMCID: PMC2096601 DOI: 10.1091/mbc.e07-06-0622] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Retrograde transport pathways from early/recycling endosomes to the trans-Golgi network (TGN) are poorly defined. We have investigated the role of TGN golgins in retrograde trafficking. Of the four TGN golgins, p230/golgin-245, golgin-97, GCC185, and GCC88, we show that GCC88 defines a retrograde transport pathway from early endosomes to the TGN. Depletion of GCC88 in HeLa cells by interference RNA resulted in a block in plasma membrane-TGN recycling of two cargo proteins, TGN38 and a CD8 mannose-6-phosphate receptor cytoplasmic tail fusion protein. In GCC88-depleted cells, cargo recycling was blocked in the early endosome. Depletion of GCC88 dramatically altered the TGN localization of the t-SNARE syntaxin 6, a syntaxin required for endosome to TGN transport. Furthermore, the transport block in GCC88-depleted cells was rescued by syntaxin 6 overexpression. Internalized Shiga toxin was efficiently transported from endosomes to the Golgi of GCC88-depleted cells, indicating that Shiga toxin and TGN38 are internalized by distinct retrograde transport pathways. These findings have identified an essential role for GCC88 in the localization of TGN fusion machinery for transport from early endosomes to the TGN, and they have allowed the identification of a retrograde pathway which differentially selects TGN38 and mannose-6-phosphate receptor from Shiga toxin.
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Affiliation(s)
- Zi Zhao Lieu
- *The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia; and
| | - Merran C. Derby
- *The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia; and
| | - Rohan D. Teasdale
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Charles Hart
- *The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia; and
| | - Priscilla Gunn
- *The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia; and
| | - Paul A. Gleeson
- *The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia; and
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14
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Derby MC, Lieu ZZ, Brown D, Stow JL, Goud B, Gleeson PA. The trans-Golgi Network Golgin, GCC185, is Required for Endosome-to-Golgi Transport and Maintenance of Golgi Structure. Traffic 2007; 8:758-73. [PMID: 17488291 DOI: 10.1111/j.1600-0854.2007.00563.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Four mammalian golgins are specifically targeted to the trans-Golgi network (TGN) membranes via their C-terminal GRIP domains. The TGN golgins, p230/golgin-245 and golgin-97, are recruited via the GTPase Arl1, whereas the TGN golgin GCC185 is recruited independently of Arl1. Here we show that GCC185 is localized to a region of the TGN distinct from Arl1 and plays an essential role in maintaining the organization of the Golgi apparatus. Using both small interfering RNA (siRNA) and microRNA (miRNA), we show that depletion of GCC185 in HeLa cells frequently resulted in fragmentation of the Golgi apparatus. Golgi apparatus fragments were dispersed throughout the cytoplasm and contained both cis and trans markers. Trafficking of anterograde and retrograde cargo was analysed over an extended period following GCC185 depletion. Early effects of GCC185 depletion included a perturbation in the distribution of the mannose-6-phosphate receptor and a block in shiga toxin trafficking to the Golgi apparatus, which occurred in parallel with the fragmentation of the Golgi ribbon. Internalized shiga toxin accumulated in Rab11-positive endosomes, indicating GCC185 is essential for transport between the recycling endosome and the TGN. In contrast, the plasma membrane-TGN recycling protein TGN38 was efficiently transported into GCC185-depleted Golgi apparatus fragments throughout a 96-h period, and anterograde transport of E-cadherin was functional until a late stage of GCC185 depletion. This study demonstrated (i) a more effective long-term depletion of GCC185 using miRNA than siRNA and (ii) a dual role for the GCC185 golgin in the regulation of endosome-to-TGN membrane transport and in the organization of the Golgi apparatus.
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Affiliation(s)
- Merran C Derby
- Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria 3010, Australia, and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
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15
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Bonifacino JS, Rojas R. Retrograde transport from endosomes to the trans-Golgi network. Nat Rev Mol Cell Biol 2006; 7:568-79. [PMID: 16936697 DOI: 10.1038/nrm1985] [Citation(s) in RCA: 486] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A subset of intracellular transmembrane proteins such as acid-hydrolase receptors, processing peptidases and SNAREs, as well as extracellular protein toxins such as Shiga toxin and ricin, undergoes 'retrograde' transport from endosomes to the trans-Golgi network. Here, we discuss recent studies that have begun to unravel the molecular machinery that is involved in this process. We also propose a central role for a 'tubular endosomal network' in sorting to recycling pathways that lead not only to the trans-Golgi network but also to different plasma-membrane domains and to specialized storage vesicles.
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Affiliation(s)
- Juan S Bonifacino
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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16
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McNamara JO, Grigston JC, VanDongen HMA, VanDongen AMJ. Rapid dendritic transport of TGN38, a putative cargo receptor. ACTA ACUST UNITED AC 2004; 127:68-78. [PMID: 15306122 DOI: 10.1016/j.molbrainres.2004.05.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2004] [Indexed: 11/29/2022]
Abstract
Protein transport to and from the postsynaptic plasma membrane is thought to be of central importance for synaptic plasticity. However, the molecular details of such processes are poorly understood. One mechanism by which membrane and secretory proteins may be transported to and from postsynaptic membranes is via cargo receptors. We studied the dendritic transport of TGN38, a putative cargo receptor thought to mediate protein transport between the trans-Golgi network (TGN), endosomes, and the plasma membrane. With fluorescence time-lapse imaging of neurons expressing a TGN38-green fluorescent protein fusion protein (GFP-TGN38), we observed rapid bidirectional dynamics of the protein in dendritic shafts. In addition, the protein was present on the surface and on intracellular membranes of dendrites and dendritic spines. Finally, GFP-TGN38 was found to cycle rapidly between the plasma membrane and intracellular membranes within dendrites, including those of spines. Together, our results suggest a role for TGN38 in facilitating rapid changes in the protein composition of postsynaptic membranes.
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Affiliation(s)
- James O McNamara
- Department of Neurobiology, Duke University Medical Center, P.O. Box 3209, Durham, NC 27710, USA
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17
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Sandoval IV, Bakke O. Targeting of membrane proteins to endosomes and lysosomes. Trends Cell Biol 2004; 4:292-7. [PMID: 14731593 DOI: 10.1016/0962-8924(94)90220-8] [Citation(s) in RCA: 237] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The pathways involved in targeting membrane proteins to lysosomes are extraordinarily complex. Newly synthesized proteins in the ER are transported to the Golgi complex, and upon arrival at the trans Golgi network (TGN) are targeted either directly to endosomes, or first to the cell surface from where they can be rapidly internalized into the endocytic pathway for delivery to lysosomes. The routes to endosomes are specified by sorting motifs in the cytoplasmic tails of the proteins that are recognized at the TGN or plasma membrane. The molecular details of these processes are just emerging.
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Affiliation(s)
- I V Sandoval
- Centro de Biologia Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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18
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Lee SS, Banting G. Characterisation of the lumenal domain of TGN38 and effects of elevated expression of TGN38 on glycoprotein secretion. Eur J Cell Biol 2002; 81:609-21. [PMID: 12494998 DOI: 10.1078/0171-9335-00279] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The TGN-localised, type I integral membrane protein TGN38 has previously been suggested to play a role as a cargo transporter within mammalian cells. We have undertaken a series of experiments designed to address this hypothesis, and, in so doing, have partially characterised the glycosylation status of the lumenal domain of TGN38. We find that elevated expression of different regions of the lumenal domain of TGN38 has no reproducible effect on secretion from stably transfected NRK cells expressing the different lumenal domain constructs; neither does it affect the gross morphology of organelles of the secretory and endocytic pathways. However, we observed that, whilst elevated expression of full-length TGN38 in stably transfected NRK cells does not have any significant effect on the morphology of organelles of the secretory and endocytic pathways, it does lead to a change in the pattern of protein secretion from these cells. In particular, elevated expression of full-length TGN38 led to increased secretion of a 48-kDa glycoprotein identified as plasminogen activator inhibitor-1.
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Affiliation(s)
- San San Lee
- Department of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK
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19
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Nothwehr SF, Ha SA, Bruinsma P. Sorting of yeast membrane proteins into an endosome-to-Golgi pathway involves direct interaction of their cytosolic domains with Vps35p. J Cell Biol 2000; 151:297-310. [PMID: 11038177 PMCID: PMC2192648 DOI: 10.1083/jcb.151.2.297] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Resident late-Golgi membrane proteins in Saccharomyces cerevisiae are selectively retrieved from a prevacuolar-endosomal compartment, a process dependent on aromatic amino acid-based sorting determinants on their cytosolic domains. The formation of retrograde vesicles from the prevacuolar compartment and the selective recruitment of vesicular cargo are thought to be mediated by a peripheral membrane retromer protein complex. We previously described mutations in one of the retromer subunit proteins, Vps35p, which caused cargo-specific defects in retrieval. By genetic and biochemical means we now show that Vps35p directly associates with the cytosolic domains of cargo proteins. Chemical cross-linking, followed by coimmunoprecipitation, demonstrated that Vps35p interacts with the cytosolic domain of A-ALP, a model late-Golgi membrane protein, in a retrieval signal-dependent manner. Furthermore, mutations in the cytosolic domains of A-ALP and another cargo protein, Vps10p, were identified that suppressed cargo-specific mutations in Vps35p but did not suppress the retrieval defects of a vps35 null mutation. Suppression was shown to be due to an improvement in protein sorting at the prevacuolar compartment. These data strongly support a model in which Vps35p acts as a "receptor" protein for recognition of the retrieval signal domains of cargo proteins during their recruitment into retrograde vesicles.
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Affiliation(s)
- S F Nothwehr
- Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211, USA.
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20
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Abstract
TGN38 luminal domain (TGN38LD) was expressed in Cos-7 cells to identify potential binding partners. The luminal domain was secreted but, surprisingly, a significant portion bound to the plasma membrane. Cells overexpressing TGN38LD or the full-length molecule detached from the substratum and left footprints positive for TGN38. Unexpectedly, in these cells, TGN38 colocalizes with integrin alpha 5 beta 1 at the Golgi, the cell surface or in the footprints and an increased amount of both integrin subunits on the plasma membrane was observed. Under physiological conditions when TGN38 is not overexpressed, it interacts with integrin beta 1. This was demonstrated by reciprocal co-immunoprecipitation of integrin beta 1 and TGN38. Functional analysis reveals that modification of the trafficking of TGN38 results in a parallel change in the distribution of integrin alpha 5 beta 1, leading to the conclusion that TGN38 is involved in the trafficking of integrin beta 1.
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Affiliation(s)
- J Wang
- Department of Cellular & Structural Biology, Box B-111, University of Colorado School of Medicine, 4200 E 9th Ave., Denver, CO 80262, USA
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21
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Nothwehr SF, Bruinsma P, Strawn LA. Distinct domains within Vps35p mediate the retrieval of two different cargo proteins from the yeast prevacuolar/endosomal compartment. Mol Biol Cell 1999; 10:875-90. [PMID: 10198044 PMCID: PMC25208 DOI: 10.1091/mbc.10.4.875] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Resident membrane proteins of the trans-Golgi network (TGN) of Saccharomyces cerevisiae are selectively retrieved from a prevacuolar/late endosomal compartment. Proper cycling of the carboxypeptidase Y receptor Vps10p between the TGN and prevacuolar compartment depends on Vps35p, a hydrophilic peripheral membrane protein. In this study we use a temperature-sensitive vps35 allele to show that loss of Vps35p function rapidly leads to mislocalization of A-ALP, a model TGN membrane protein, to the vacuole. Vps35p is required for the prevacuolar compartment-to-TGN transport of both A-ALP and Vps10p. This was demonstrated by phenotypic analysis of vps35 mutant strains expressing A-ALP mutants lacking either the retrieval or static retention signals and by an assay for prevacuolar compartment-to-TGN transport. A novel vps35 allele was identified that was defective for retrieval of A-ALP but functional for retrieval of Vps10p. Moreover, several other vps35 alleles were identified with the opposite characteristics: they were defective for Vps10p retrieval but near normal for A-ALP localization. These data suggest a model in which distinct structural features within Vps35p are required for associating with the cytosolic domains of each cargo protein during the retrieval process.
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Affiliation(s)
- S F Nothwehr
- Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211, USA.
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22
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Abstract
There is a growing body of evidence that local protein synthesis beneath synapses may provide a novel mechanism underlying plastic phenomena. In vivo and in vitro biochemical data show that dendrites can perform translation and glycosylation. Using antibodies directed against the eukaryotic protein synthetic machinery, we sought to identify the structures implicated in nonperinuclear translation, namely dendritic and postsynaptic protein synthesis. We performed a morphological and immunocytochemical analysis of ventromedial horn rat spinal cord neurons using both light and electron microscopy. We show at the cellular level that, in vivo, protein synthesis macrocomplexes (ribosomes and eIF-2) as well as the endomembranous system implicated in cotranslational and posttranslational modifications (endoplasmic reticulum and Golgi cisternae) penetrated some dendrites. Membrane-limited organelles of different shape and size are present close to the postsynaptic differentiations of most synapses, independently of their localization on the neuronal surface. We demonstrate (1) that some cisternae are immunoreactive for antibodies against ribosomal proteins and eIF-2, and (2) that markers of endoplasmic reticulum (BiP), intermediate compartment, and Golgi complex (rab1, CTR433, TGN38) label subsets of these subsynaptic organelles. Therefore, these findings indicate that synapses are equipped with the essential elements required for the synthesis and insertion of a well folded and glycosylated transmembrane protein.
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23
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Ghosh RN, Mallet WG, Soe TT, McGraw TE, Maxfield FR. An endocytosed TGN38 chimeric protein is delivered to the TGN after trafficking through the endocytic recycling compartment in CHO cells. J Cell Biol 1998; 142:923-36. [PMID: 9722606 PMCID: PMC2132871 DOI: 10.1083/jcb.142.4.923] [Citation(s) in RCA: 202] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/1998] [Revised: 07/13/1998] [Indexed: 02/08/2023] Open
Abstract
To examine TGN38 trafficking from the cell surface to the TGN, CHO cells were stably transfected with a chimeric transmembrane protein, TacTGN38. We used fluorescent and 125I-labeled anti-Tac IgG and Fab fragments to follow TacTGN38's postendocytic trafficking. At steady-state, anti-Tac was mainly in the TGN, but shortly after endocytosis it was predominantly in early endosomes. 11% of cellular TacTGN38 is on the plasma membrane. Kinetic analysis of trafficking of antibodies bound to TacTGN38 showed that after short endocytic pulses, 80% of internalized anti-Tac returned to the cell surface (t1/2 = 9 min), and the remainder trafficked to the TGN. When longer filling pulses and chases were used to load anti-Tac into the TGN, it returned to the cell surface with a t1/2 of 46 min. Quantitative confocal microscopy analysis also showed that fluorescent anti-Tac fills the TGN with a 46-min t1/2. Using the measured rate constants in a simple kinetic model, we predict that 82% of TacTGN38 is in the TGN, and 7% is in endosomes. TacTGN38 leaves the TGN slowly, which accounts for its steady-state distribution despite the inefficient targeting from the cell surface to the TGN.
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Affiliation(s)
- R N Ghosh
- Department of Biochemistry, Cornell University Medical College, New York, New York 10021, USA
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24
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Hauri H, Schweizer A. The
ER
–Golgi Membrane System: Compartmental Organization and Protein Traffic. Compr Physiol 1997. [DOI: 10.1002/cphy.cp140115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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25
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Banting G, Ponnambalam S. TGN38 and its orthologues: roles in post-TGN vesicle formation and maintenance of TGN morphology. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1355:209-17. [PMID: 9060992 DOI: 10.1016/s0167-4889(96)00146-2] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- G Banting
- Department of Biochemistry, University of Bristol, UK
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26
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Johnson AO, Ghosh RN, Dunn KW, Garippa R, Park J, Mayor S, Maxfield FR, McGraw TE. Transferrin receptor containing the SDYQRL motif of TGN38 causes a reorganization of the recycling compartment but is not targeted to the TGN. J Biophys Biochem Cytol 1996; 135:1749-62. [PMID: 8991088 PMCID: PMC2133967 DOI: 10.1083/jcb.135.6.1749] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The SDYQRL motif of the cytoplasmic domain of TGN38 is involved in targeting TGN38 from endosomes to the TGN. To create a system for studying this pathway, we replaced the native transferrin receptor (TR) internalization motif (YTRF) with the SDYQRL TGN-targeting motif. The advantages of using TR as a reporter molecule include the ability to monitor trafficking, in both biochemical and microscopy experiments, using the natural ligand transferrin. When expressed in CHO cells, the SDYQRL-TR construct accumulated in juxtanuclear tubules and vesicles that are in the vicinity of the TGN. The SDYQRL-TR-containing structures, however, do not colocalize with TGN markers (e.g., NBD ceramide), and therefore the SDYQRL motif is not sufficient to target the TR to the TGN. The morphology of the SDYQRL-TR-containing juxtanuclear structures is different from the recycling compartment found in cells expressing the wild-type TR. In addition, the SDYQRL-TR-containing juxtanuclear compartment is more acidic than the recycling compartment in cells expressing the wild-type TR. The juxtanuclear compartment, however, is a bona fide recycling compartment since SDYQRL-TR was recycled back to the cell surface at a rate comparable to the wild-type TR, and sphingomyelin and cellubrevin, both of which label all compartments of the endocytic recycling pathway, colocalize with SDYQRL-TR in the juxtanuclear structures. These findings demonstrate that expression of the SDYQRL-TR construct alters the morphology and pH of endocytic recycling compartments rather than selectively affecting the intracellular trafficking pathway of the SDYQRL-TR construct. Therefore, the SDYQRL trafficking motif is not simply a molecular address that targets proteins to the TGN, but it can play an active role in determining the physical characteristics of endosomal compartments.
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Affiliation(s)
- A O Johnson
- Department of Pathology, Columbia University, New York 10032, USA
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27
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Traub LM, Bannykh SI, Rodel JE, Aridor M, Balch WE, Kornfeld S. AP-2-containing clathrin coats assemble on mature lysosomes. J Cell Biol 1996; 135:1801-14. [PMID: 8991092 PMCID: PMC2133961 DOI: 10.1083/jcb.135.6.1801] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Coat proteins appear to play a general role in intracellular protein trafficking by coordinating a membrane budding event with cargo selection. Here we show that the AP-2 adaptor, a clathrin-associated coat-protein complex that nucleates clathrin-coated vesicle formation at the cell surface, can also initiate the assembly of normal polyhedral clathrin coats on dense lysosomes under physiological conditions in vitro. Clathrin coat formation on lysosomes is temperature dependent, displays an absolute requirement for ATP, and occurs in both semi-intact cells and on purified lysosomes, suggesting that clathrin-coated vesicles might regulate retrograde membrane traffic out of the lysosomal compartment.
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Affiliation(s)
- L M Traub
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Harter C, Wieland F. The secretory pathway: mechanisms of protein sorting and transport. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1286:75-93. [PMID: 8652612 DOI: 10.1016/0304-4157(96)00003-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- C Harter
- Institut für Biochemie I, Universität Heidelberg, Germany
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29
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Nothwehr SF, Bryant NJ, Stevens TH. The newly identified yeast GRD genes are required for retention of late-Golgi membrane proteins. Mol Cell Biol 1996; 16:2700-7. [PMID: 8649377 PMCID: PMC231260 DOI: 10.1128/mcb.16.6.2700] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Processing of A-ALP, a late-Golgi membrane protein constructed by fusing the cytosolic domain of dipeptidyl aminopeptidase A to the transmembrane and lumenal domains of alkaline phosphatase (ALP), serves as a convenient assay for loss of retention of late-Golgi membrane proteins in Saccharomyces cerevisiae. In this study, a large group of novel grd (for Golgi retention defective) yeast mutants, representing 18 complementation groups, were identified on the basis of their mislocalization of A-ALP to the vacuole, where it was proteolytically processed and thus became enzymatically activated. All of the grd mutants exhibited significant mislocalization of A-ALP, as measured by determining the kinetics of A-ALP processing and by analyzing its
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Affiliation(s)
- S F Nothwehr
- Division of Biological Sciences, University of Missouri, Columbia 65211, USA
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30
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Takahashi S, Nakagawa T, Banno T, Watanabe T, Murakami K, Nakayama K. Localization of furin to the trans-Golgi network and recycling from the cell surface involves Ser and Tyr residues within the cytoplasmic domain. J Biol Chem 1995; 270:28397-401. [PMID: 7499343 DOI: 10.1074/jbc.270.47.28397] [Citation(s) in RCA: 111] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Furin is a membrane-associated endoprotease that catalyzes cleavage of precursor proteins at Arg-X-Lys/Arg-Arg sites. Although, at steady state, furin is predominantly found in the trans-Golgi network (TGN), it also cycles between the TGN and the cell surface. Recently, the cytoplasmic tail of furin has been shown to be sufficient for its localization to the TGN. Within the cytoplasmic domain, there are Ser residues, which we now show are sites for phosphorylation by casein kinase II in vitro, and a Tyr-containing sequence, both of which have been shown to be important for other TGN proteins to localize to this compartment. In the present study, we show by site-directed mutagenesis that these residues are important for TGN localization and recycling of furin. Mutation of the Ser residues abrogated the TGN localization. By contrast, mutation of the Tyr residue did not affect the TGN localization but impaired the internalization from the plasma membrane. These observations suggest that distinct cytoplasmic determinants are responsible for retention in the TGN and retrieval from the cell surface of furin.
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Affiliation(s)
- S Takahashi
- Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan
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31
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Kasai K, Takahashi S, Murakami K, Nakayama K. Strain-specific presence of two TGN38 isoforms and absence of TGN41 in mouse. J Biol Chem 1995; 270:14471-6. [PMID: 7540170 DOI: 10.1074/jbc.270.24.14471] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
TGN38 and TGN41 are isoforms of an integral membrane protein that is predominantly localized to the trans-Golgi network (TGN) in rat cells. They have been proposed to form a heterodimer and to be involved in the budding of exocytic transport vesicles from the TGN. By cDNA cloning and analysis using polymerase chain reaction, we found that there were two TGN38 isoforms in a strain of mouse (ICR), whereas other strains examined (BALB/c, DBA/2, and C57BL/6) had only one TGN38. The major difference between the two isoforms was in the number of characteristic octapeptide repeats. Apart from this, there were several nucleotide substitutions between them. The two isoforms appeared to be derived from two distinct genes but not from one gene via alternative splicing. Furthermore, we failed to show the presence of TGN41 in all the strains examined. This result suggests that TGN38 may function as a monomer or a homodimer in mouse cells.
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Affiliation(s)
- K Kasai
- Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan
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32
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Abstract
The Golgi apparatus maintains a highly organized structure in spite of the intense membrane traffic which flows into and out of this organelle. Resident Golgi proteins must have localization signals to ensure that they are targeted to the correct Golgi compartment and not swept further along the secretory pathway. There are a number of distinct groups of Golgi membrane proteins, including glycosyltransferases, recycling trans-Golgi network proteins, peripheral membrane proteins, receptors and viral glycoproteins. Recent studies indicate that there are a number of different Golgi localization signals and mechanisms for retaining proteins to the Golgi apparatus. This review focuses on the current knowledge in this field.
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Affiliation(s)
- P A Gleeson
- Department of Pathology and Immunology, Monash University Medical School, Alfred Hospital, Melbourne, Victoria, Australia
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33
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Bosshart H, Humphrey J, Deignan E, Davidson J, Drazba J, Yuan L, Oorschot V, Peters PJ, Bonifacino JS. The cytoplasmic domain mediates localization of furin to the trans-Golgi network en route to the endosomal/lysosomal system. J Cell Biol 1994; 126:1157-72. [PMID: 7914893 PMCID: PMC2120164 DOI: 10.1083/jcb.126.5.1157] [Citation(s) in RCA: 140] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
To investigate the mechanisms of membrane protein localization to the Golgi complex, we have examined the intracellular trafficking of epitope-tagged forms of the mammalian endopeptidase, furin, in stably transformed rat basophilic leukemia cells. Our studies show that furin is predominantly localized to the trans-Golgi network (TGN) at steady state, with smaller amounts present in intracellular vesicles. Biochemical and morphological analyses reveal that furin is progressively delivered to a lysosomal compartment, where it is degraded. Analyses of furin deletion mutants and chimeric proteins show that the cytoplasmic domain is both necessary and sufficient for localization to the TGN in various cell types. Interestingly, deletion of most of the cytoplasmic domain of furin results in a molecule that is predominantly localized to intracellular vesicles, some of which display characteristics of lysosomes. To a lesser extent, the cytoplasmically deleted molecule is also localized to the plasma membrane. These observations suggest the existence of an additional determinant for targeting to the endosomal/lysosomal system within the lumenal and/or transmembrane domains of furin. Thus, the overall pattern of trafficking and steady state localization of furin are determined by targeting information contained within more than one region of the molecule.
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Affiliation(s)
- H Bosshart
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
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34
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Reaves B, Banting G. Vacuolar ATPase inactivation blocks recycling to the trans-Golgi network from the plasma membrane. FEBS Lett 1994; 345:61-6. [PMID: 8194602 DOI: 10.1016/0014-5793(94)00437-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
TGN38/41 is an integral membrane protein which recycles between the trans-Golgi network (TGN) and the cell surface but is predominantly located in the TGN of rat (NRK) cells at steady state. As part of our studies on the mechanism and route of recycling between the TGN and the cell surface we have used chloroquine or Bafilomycin A1 to modulate the lumenal pH of endocytic organelles. The data we present demonstrate that inactivation of the proton pump which maintains the acidic environment within the lumen of endocytic organelles leads to an accumulation of TGN38/41 in early endosomes. These data confirm the observation that TGN38/41 recycles between the plasma membrane and the TGN and identifies a specific block in that recycling pathway.
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Affiliation(s)
- B Reaves
- Department of Biochemistry, School of Medical Sciences, University of Bristol, UK
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35
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Ponnambalam S, Rabouille C, Luzio JP, Nilsson T, Warren G. The TGN38 glycoprotein contains two non-overlapping signals that mediate localization to the trans-Golgi network. J Biophys Biochem Cytol 1994; 125:253-68. [PMID: 8163544 PMCID: PMC2120028 DOI: 10.1083/jcb.125.2.253] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The membrane-spanning and cytoplasmic domains of CD4 and CD8 were replaced by those of TGN38. After transient expression in HeLa cells, the location of the hybrid proteins was determined using immunofluorescence and quantitative immuno-electron microscopy, FACS analysis and metabolic labeling. The membrane-spanning domain was found to contain a signal that localized hybrid proteins to the TGN. This was in addition to the signal previously identified in the cytoplasmic domain (Bos, K., C. Wraight, and K. Stanley. 1993. EMBO (Eur. Mol. Biol. Organ) J. 12:2219-2228. Humphrey, J. S., P. J. Peters, L. C. Yuan, and J. S. Bonifacino. 1993. J. Cell Biol. 120:1123-1135. Wong, S. H., and W. Hong. 1993. J. Biol. Chem. 268:22853-22862). The different properties of these two signals suggest that each operates by a different mechanism.
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Affiliation(s)
- S Ponnambalam
- Cell Biology Laboratory, Imperial Cancer Research Fund, Lincoln's Inn Fields, London, United Kingdom
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36
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Barroso M, Sztul ES. Basolateral to apical transcytosis in polarized cells is indirect and involves BFA and trimeric G protein sensitive passage through the apical endosome. J Biophys Biochem Cytol 1994; 124:83-100. [PMID: 7905002 PMCID: PMC2119901 DOI: 10.1083/jcb.124.1.83] [Citation(s) in RCA: 174] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have used temperature and nocodazole blocks in an in vivo basolateral to apical transcytosis assay to dissociate the early transcytotic steps occurring during the formation of transcytotic vesicles and their microtubule-dependent translocation into the apical region, from the late steps when transcytotic cargo is delivered into the apical media. We found that polarized MDCK cells transfected with rabbit polymeric IgA receptor (pIgA-R) internalize basolaterally added pIgA-R ligand ([Fab]2 fragment of IgG against the receptor's ectodomain) at 17 degrees C but do not deliver it to the apical PM. Instead, the ligand accumulates in an apically localized transcytotic compartment, distal to the basolateral endosome and the microtubule-requiring translocation step. We have characterized this compartment and show that it is distinct from basolateral transferrin recycling endosomes, basolateral early endosomes or late endosomes or lysosomes. The apical transcytotic compartment colocalizes with the compartment containing apically recycling membrane markers (ricin and apically internalized pIgA-R ligand) but is distinct from the compartment receiving apically internalized fluid phase marker (BSA). This compartment is an intermediate station of the overall pathway since transcytotic ligand can exit the compartment and be released into the apical medium when cells preloaded at 17 degrees C are subsequently incubated at 37 degrees C. We have used this system to examine the effect of Brefeldin A (BFA) and the involvement of trimeric GTPases in the late (post apical transcytotic compartment) steps of the transcytotic pathway. We found that addition of BFA or cholera toxin, a known activator of Gs alpha, to cells preloaded with transcytotic ligand at 17 degrees C significantly inhibits the exit of ligand from the apical transcytotic compartment. General structure and function of the apical endosome are not affected since neither BFA nor cholera toxin inhibit the recycling of apically internalized membrane markers (ricin and pIgA-R ligand) from the same compartment. The data suggest that transcytosis connects the "membrane-sorting" sub-domain of the basolateral endosome with a homologous sub-domain of the apical endosome and that exit of transcytosing cargo from the apical endosome is controlled by a BFA and trimeric G protein sensitive mechanism, distinct from that used for recycling of apically internalized proteins (ricin or pIgA-R).
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Affiliation(s)
- M Barroso
- Department of Molecular Biology, Princeton University, New Jersey 08544
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37
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Wilsbach K, Payne GS. Dynamic retention of TGN membrane proteins in Saccharomyces cerevisiae. Trends Cell Biol 1993; 3:426-32. [PMID: 14731888 DOI: 10.1016/0962-8924(93)90031-u] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In a secretory pathway organelle like the Golgi complex, resident proteins are retained in the face of substantial protein flux to subsequent destinations. Recently, molecular genetic strategies have been used to study membrane protein retention in a compartment of the yeast Saccharomyces cerevisiae that is analogous to the trans Golgi network (TGN) of mammalian cells. These studies have defined retention signals containing aromatic amino acids in the TGN proteins' cytoplasmic domains. The identification of mutants that fail to retain TGN proteins has offered the first glimpse into the components involved in retention. The phenotypes of these mutants suggest that retention involves retrieval of TGN proteins from an endosomal compartment.
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Affiliation(s)
- K Wilsbach
- Department of Biological Chemistry, School of Medicine, and Molecular Biology Institute, University of California, Los Angeles, CA 90024, USA
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38
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Luzio JP, Banting G. Eukaryotic membrane traffic: retrieval and retention mechanisms to achieve organelle residence. Trends Biochem Sci 1993; 18:395-8. [PMID: 8256290 DOI: 10.1016/0968-0004(93)90097-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The localization of integral membrane proteins to specific organelles is necessary to maintain the functional integrity of eukaryotic cells. Recent studies indicate firstly, that retrieval and retention mechanisms, requiring specific primary sequence motifs, are used to ensure that proteins reside in specific membranes of the secretory and endocytic pathways and secondly, that these membranes exist as components of two juxtaposed systems separated by the cisternae of the Golgi stack.
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Affiliation(s)
- J P Luzio
- Department of Clinical Biochemistry, University of Cambridge, Addenbrookes Hospital, UK
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