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Stewart SE, Ashkenazi A, Williamson A, Rubinsztein DC, Moreau K. Transbilayer phospholipid movement facilitates the translocation of annexin across membranes. J Cell Sci 2018; 131:jcs217034. [PMID: 29930080 PMCID: PMC6080606 DOI: 10.1242/jcs.217034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 06/06/2018] [Indexed: 02/03/2023] Open
Abstract
Annexins are cytosolic phospholipid-binding proteins that can be found on the outer leaflet of the plasma membrane. The extracellular functions of annexin include modulating fibrinolysis activity and cell migration. Despite having well-described extracellular functions, the mechanism of annexin transport from the cytoplasmic inner leaflet to the extracellular outer leaflet of the plasma membrane remains unclear. Here, we show that the transbilayer movement of phospholipids facilitates the transport of annexins A2 and A5 across membranes in cells and in liposomes. We identified TMEM16F (also known as anoctamin-6, ANO6) as a lipid scramblase required for transport of these annexins to the outer leaflet of the plasma membrane. This work reveals a mechanism for annexin translocation across membranes which depends on plasma membrane phospholipid remodelling.
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Affiliation(s)
- Sarah E Stewart
- University of Cambridge, Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Cambridge, CB2 0QQ, UK
| | - Avraham Ashkenazi
- University of Cambridge, Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Athena Williamson
- University of Cambridge, Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Cambridge, CB2 0QQ, UK
| | - David C Rubinsztein
- University of Cambridge, Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
- UK Dementia Research Institute, Cambridge Biomedical Campus, Hills Road, Cambridge, UK
| | - Kevin Moreau
- University of Cambridge, Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Cambridge, CB2 0QQ, UK
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102
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Kim J, Gee HY, Lee MG. Unconventional protein secretion – new insights into the pathogenesis and therapeutic targets of human diseases. J Cell Sci 2018; 131:131/12/jcs213686. [DOI: 10.1242/jcs.213686] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
ABSTRACT
Most secretory proteins travel through a well-documented conventional secretion pathway involving the endoplasmic reticulum (ER) and the Golgi complex. However, recently, it has been shown that a significant number of proteins reach the plasma membrane or extracellular space via unconventional routes. Unconventional protein secretion (UPS) can be divided into two types: (i) the extracellular secretion of cytosolic proteins that do not bear a signal peptide (i.e. leaderless proteins) and (ii) the cell-surface trafficking of signal-peptide-containing transmembrane proteins via a route that bypasses the Golgi. Understanding the UPS pathways is not only important for elucidating the mechanisms of intracellular trafficking pathways but also has important ramifications for human health, because many of the proteins that are unconventionally secreted by mammalian cells and microorganisms are associated with human diseases, ranging from common inflammatory diseases to the lethal genetic disease of cystic fibrosis. Therefore, it is timely and appropriate to summarize and analyze the mechanisms of UPS involvement in disease pathogenesis, as they may be of use for the development of new therapeutic approaches. In this Review, we discuss the intracellular trafficking pathways of UPS cargos, particularly those related to human diseases. We also outline the disease mechanisms and the therapeutic potentials of new strategies for treating UPS-associated diseases.
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Affiliation(s)
- Jiyoon Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Heon Yung Gee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Min Goo Lee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
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103
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Tang BL. Unconventional Secretion and Intercellular Transfer of Mutant Huntingtin. Cells 2018; 7:cells7060059. [PMID: 29904030 PMCID: PMC6025013 DOI: 10.3390/cells7060059] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 06/08/2018] [Accepted: 06/12/2018] [Indexed: 01/17/2023] Open
Abstract
The mechanism of intercellular transmission of pathological agents in neurodegenerative diseases has received much recent attention. Huntington’s disease (HD) is caused by a monogenic mutation in the gene encoding Huntingtin (HTT). Mutant HTT (mHTT) harbors a CAG repeat extension which encodes an abnormally long polyglutamine (polyQ) repeat at HTT’s N-terminus. Neuronal pathology in HD is largely due to the toxic gain-of-function by mHTT and its proteolytic products, which forms both nuclear and cytoplasmic aggregates that perturb nuclear gene transcription, RNA splicing and transport as well cellular membrane dynamics. The neuropathological effects of mHTT have been conventionally thought to be cell-autonomous in nature. Recent findings have, however, indicated that mHTT could be secreted by neurons, or transmitted from one neuronal cell to another via different modes of unconventional secretion, as well as via tunneling nanotubes (TNTs). These modes of transmission allow the intercellular spread of mHTT and its aggregates, thus plausibly promoting neuropathology within proximal neuronal populations and between neurons that are connected within neural circuits. Here, the various possible modes for mHTT’s neuronal cell exit and intercellular transmission are discussed.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, 117597 Singapore, Singapore.
- NUS Graduate School for Integrative Sciences and Engineering, 117456 Singapore, Singapore.
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104
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Bingol B. Autophagy and lysosomal pathways in nervous system disorders. Mol Cell Neurosci 2018; 91:167-208. [PMID: 29729319 DOI: 10.1016/j.mcn.2018.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 04/26/2018] [Accepted: 04/28/2018] [Indexed: 12/12/2022] Open
Abstract
Autophagy is an evolutionarily conserved pathway for delivering cytoplasmic cargo to lysosomes for degradation. In its classically studied form, autophagy is a stress response induced by starvation to recycle building blocks for essential cellular processes. In addition, autophagy maintains basal cellular homeostasis by degrading endogenous substrates such as cytoplasmic proteins, protein aggregates, damaged organelles, as well as exogenous substrates such as bacteria and viruses. Given their important role in homeostasis, autophagy and lysosomal machinery are genetically linked to multiple human disorders such as chronic inflammatory diseases, cardiomyopathies, cancer, and neurodegenerative diseases. Multiple targets within the autophagy and lysosomal pathways offer therapeutic opportunities to benefit patients with these disorders. Here, I will summarize the mechanisms of autophagy pathways, the evidence supporting a pathogenic role for disturbed autophagy and lysosomal degradation in nervous system disorders, and the therapeutic potential of autophagy modulators in the clinic.
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Affiliation(s)
- Baris Bingol
- Genentech, Inc., Department of Neuroscience, 1 DNA Way, South San Francisco 94080, United States.
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105
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Gee HY, Kim J, Lee MG. Unconventional secretion of transmembrane proteins. Semin Cell Dev Biol 2018; 83:59-66. [PMID: 29580969 DOI: 10.1016/j.semcdb.2018.03.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/22/2018] [Accepted: 03/22/2018] [Indexed: 01/09/2023]
Abstract
Over the past 20 years it has become evident that eukaryotic cells utilize both conventional and unconventional pathways to deliver proteins to their target sites. Most proteins with a signal peptide and/or a transmembrane domain are conventionally transported through the endoplasmic reticulum to the Golgi apparatus and then to the plasma membrane. However, an increasing number of both soluble cargos (Type I, II, and III) and integral membrane proteins (Type IV) have been found to reach the plasma membrane via unconventional protein secretion (UPS) pathways that bypass the Golgi apparatus under certain conditions, such as cellular stress or development. Well-known examples of transmembrane proteins that undergo Type IV UPS pathways are position-specific antigen subunit alpha 1 integrin, cystic fibrosis transmembrane conductance regulator, myeloproliferative leukemia virus oncogene, and pendrin. Although we collectively refer to all Golgi-bypassing routes as UPS, individual trafficking pathways are diverse compared to the conventional pathways, and the molecular mechanisms of UPS pathways are not yet completely defined. This review summarizes the intracellular trafficking pathways of UPS cargo proteins, particularly those with transmembrane domains, and discusses the molecular machinery involved in the UPS of transmembrane proteins.
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Affiliation(s)
- Heon Yung Gee
- Department of Pharmacology, Brain Korea21 Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Jiyoon Kim
- Department of Pharmacology, Brain Korea21 Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Min Goo Lee
- Department of Pharmacology, Brain Korea21 Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.
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106
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107
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Sharma R, Sharma B, Gupta A, Dhar SK. Identification of a novel trafficking pathway exporting a replication protein, Orc2 to nucleus via classical secretory pathway in Plasmodium falciparum. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018. [PMID: 29524523 DOI: 10.1016/j.bbamcr.2018.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Malaria parasites use an extensive secretory pathway to traffic a number of proteins within itself and beyond. In higher eukaryotes, Endoplasmic Reticulum (ER) membrane bound transcription factors such as SREBP are reported to get processed en route and migrate to nucleus under the influence of specific cues. However, a protein constitutively trafficked to the nucleus via classical secretory pathway has not been reported. Herein, we report the presence of a novel trafficking pathway in an apicomplexan, Plasmodium falciparum where a homologue of an Origin Recognition Complex 2 (Orc2) goes to the nucleus following its association with the ER. Our work highlights the unconventional role of ER in protein trafficking and reports for the first time an ORC homologue getting trafficked through such a pathway to the nucleus where it may be involved in DNA replication and other ancillary functions. Such trafficking pathways may have a profound impact on the cell biology of a malaria parasite and have significant implications in strategizing new antimalarials.
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Affiliation(s)
- Rahul Sharma
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Bhumika Sharma
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Ashish Gupta
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Greater Noida 201314, India
| | - Suman Kumar Dhar
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India.
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108
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Nüchel J, Ghatak S, Zuk AV, Illerhaus A, Mörgelin M, Schönborn K, Blumbach K, Wickström SA, Krieg T, Sengle G, Plomann M, Eckes B. TGFB1 is secreted through an unconventional pathway dependent on the autophagic machinery and cytoskeletal regulators. Autophagy 2018; 14:465-486. [PMID: 29297744 DOI: 10.1080/15548627.2017.1422850] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
TGFB1 (transforming growth factor beta 1) is a potent cytokine playing a driving role in development, fibrosis and cancer. It is synthesized as prodomain-growth factor complex that requires tethering to LTBP (latent transforming growth factor beta binding protein) for efficient secretion into the extracellular space. Upon release, this large latent complex is sequestered by anchorage to extracellular matrix (ECM) networks, from which the mature growth factor needs to be activated in order to reach its receptors and initiate signaling. Here, we uncovered a novel intracellular secretion pathway by which the latent TGFB1 complex reaches the plasma membrane and is released from fibroblasts, the key effector cells during tissue repair, fibrosis and in the tumor stroma. We show that secretion of latent TGFB1, but not of other selected cytokines or of bulk cargo, is regulated by fibroblast-ECM communication through ILK (integrin linked kinase) that restricts RHOA activity by interacting with ARHGAP26/GRAF1. Latent TGFB1 interacts with GORASP2/GRASP55 and is detected inside MAP1LC3-positive autophagosomal intermediates that are secreted by a RAB8A-dependent pathway. Interestingly, TGFB1 secretion is fully abrogated in human and murine fibroblasts and macrophages that lack key components of the autophagic machinery. Our data demonstrate an unconventional secretion mode of TGFB1 adding another level of control of its bioavailability and activity in order to effectively orchestrate cellular programs prone to dysregulation as seen in fibrosis and cancer.
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Affiliation(s)
- Julian Nüchel
- a Center for Biochemistry , University of Cologne , Cologne , Germany
| | - Sushmita Ghatak
- b Department of Dermatology, University of Cologne , Cologne , Germany
| | - Alexandra V Zuk
- a Center for Biochemistry , University of Cologne , Cologne , Germany
| | - Anja Illerhaus
- b Department of Dermatology, University of Cologne , Cologne , Germany
| | - Matthias Mörgelin
- c Department of Infection Medicine , Biomedical Center, University of Lund , Lund , Sweden
| | - Katrin Schönborn
- b Department of Dermatology, University of Cologne , Cologne , Germany
| | - Katrin Blumbach
- b Department of Dermatology, University of Cologne , Cologne , Germany
| | - Sara A Wickström
- d Max Planck Institute for Biology of Ageing , Cologne , Germany.,e Cologne Cluster of Excellence in Cellular Stress Responses in Aging-Associated Diseases (CECAD) , Cologne , Germany
| | - Thomas Krieg
- b Department of Dermatology, University of Cologne , Cologne , Germany.,e Cologne Cluster of Excellence in Cellular Stress Responses in Aging-Associated Diseases (CECAD) , Cologne , Germany.,f Center for Molecular Medicine Cologne , University of Cologne , Cologne , Germany
| | - Gerhard Sengle
- a Center for Biochemistry , University of Cologne , Cologne , Germany.,f Center for Molecular Medicine Cologne , University of Cologne , Cologne , Germany
| | - Markus Plomann
- a Center for Biochemistry , University of Cologne , Cologne , Germany
| | - Beate Eckes
- b Department of Dermatology, University of Cologne , Cologne , Germany
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109
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Abstract
Cell-to-cell transmission of misfolded proteins propagates proteotoxic stress in multicellular organisms when transmitted polypeptides serve as a seeding template to cause protein misfolding in recipient cells, but how misfolded proteins are released from cells to initiate this process is unclear. Misfolding-associated protein secretion (MAPS) is an unconventional protein-disposing mechanism that specifically exports misfolded cytosolic proteins including various neurodegenerative disease-causing proteins. Here we establish the HSC70 co-chaperone DNAJC5 as an essential mediator of MAPS. USP19, a previously uncovered MAPS regulator binds HSC70 and acts upstream of HSC70 and DNAJC5. We further show that as a membrane-associated protein localized preferentially to late endosomes and lysosomes, DNAJC5 can chaperone MAPS client proteins to the cell exterior. Intriguingly, upon secretion, misfolded proteins can be taken up through endocytosis and eventually degraded in the lysosome. Collectively, these findings suggest a transcellular protein quality control regulatory pathway in which a deubiquitinase-chaperone axis forms a “triaging hub”, transferring aberrant polypeptides from stressed cells to healthy ones for disposal.
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110
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Steringer JP, Nickel W. A direct gateway into the extracellular space: Unconventional secretion of FGF2 through self-sustained plasma membrane pores. Semin Cell Dev Biol 2018; 83:3-7. [PMID: 29458182 DOI: 10.1016/j.semcdb.2018.02.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/01/2018] [Accepted: 02/08/2018] [Indexed: 10/17/2022]
Abstract
As illustrated by a diverse set of examples in this special issue, multiple mechanisms of protein secretion have been identified in eukaryotes that do not involve the endoplasmic reticulum (ER) and the Golgi apparatus. Here we focus on the type I pathway with Fibroblast Growth Factor 2 (FGF2) being the most prominent example. Unconventional secretion of FGF2 from cells is mediated by direct protein translocation across the plasma membrane. A unique feature of this process is the ability of FGF2 to form its own membrane translocation intermediate through oligomerization and membrane insertion. This process depends on the phosphoinositide PI(4,5)P2 at the inner leaflet and results in the formation of lipidic membrane pores in the plasma membrane. Various lines of evidence suggest that these pores are characterized by a toroidal architecture with FGF2 oligomers being accommodated in the center of these structures. At the outer leaflet of the plasma membrane, membrane proximal heparan sulfate proteoglycans are required for the final step of FGF2 translocation into the extracellular space. Based upon mutually exclusive interactions of FGF2 with PI(4,5)P2 versus heparan sulfates, an assembly/disassembly pathway has been proposed to be the underlying principle of directional transport of FGF2 across the plasma membrane. Thus, the core mechanism of unconventional secretion of FGF2 is based upon three discrete steps with (i) PI(4,5)P2 dependent oligomerization of FGF2 at the inner leaflet, (ii) insertion of membrane spanning FGF2 oligomers into the plasma membrane and (iii) disassembly at the outer leaflet mediated by heparan sulfates that subsequently retain FGF2 on cell surfaces. This process has recently been reconstituted with an inside-out membrane model system using giant unilamellar vesicles providing a compelling explanation of how FGF2 reaches the extracellular space in an ER/Golgi independent manner. This review is part of a Special Issue of SCDB on "unconventional protein secretion" edited by Walter Nickel and Catherine Rabouille.
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Affiliation(s)
- Julia P Steringer
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.
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111
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Cadwell K, Debnath J. Beyond self-eating: The control of nonautophagic functions and signaling pathways by autophagy-related proteins. J Cell Biol 2018; 217:813-822. [PMID: 29237720 PMCID: PMC5839790 DOI: 10.1083/jcb.201706157] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 11/16/2017] [Accepted: 11/17/2017] [Indexed: 12/12/2022] Open
Abstract
The identification of conserved autophagy-related proteins (ATGs) that mediate bulk degradation of cytosolic material laid the foundation for breakthroughs linking autophagy to a litany of physiological processes and disease conditions. Recent discoveries are revealing that these same ATGs orchestrate processes that are related to, and yet clearly distinct from, classic autophagy. Autophagy-related functions include secretion, trafficking of phagocytosed material, replication and egress of viral particles, and regulation of inflammatory and immune signaling cascades. Here, we define common processes dependent on ATGs, and discuss the challenges in mechanistically separating autophagy from these related pathways. Elucidating the molecular events that distinguish how individual ATGs function promises to improve our understanding of the origin of diseases ranging from autoimmunity to cancer.
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Affiliation(s)
- Ken Cadwell
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, NY
- Department of Microbiology, New York University School of Medicine, New York, NY
| | - Jayanta Debnath
- Department of Pathology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA
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112
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Cruz-Garcia D, Malhotra V, Curwin AJ. Unconventional protein secretion triggered by nutrient starvation. Semin Cell Dev Biol 2018; 83:22-28. [PMID: 29486236 DOI: 10.1016/j.semcdb.2018.02.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/08/2018] [Accepted: 02/12/2018] [Indexed: 10/17/2022]
Abstract
It is usually assumed that eukaryotic cells secrete only proteins that contain a signal sequence for Sec61 mediated translocation into the lumen of endoplasmic reticulum (ER). Surprisingly however, many proteins, such as superoxide dismutase (SOD)1, acyl-CoA binding protein (Acb1), interleukin 1β, fibroblast growth factor 2 and the adipokine Unpaired2, to name a few, are secreted even though they lack a signal sequence. The discovery that these proteins are secreted has presented a new challenge and we describe here a common pathway by which SOD1 and Acb1 are specifically secreted upon nutrient starvation. Their secretion follows a type III unconventional pathway, requiring the exposure of a di-acidic motif, which we propose promotes their capture into a membrane compartment called CUPS (compartment for unconventional protein secretion). We suggest that CUPS, composed of membranes derived from the Golgi apparatus and endosomes, serves as a major sorting station prior to release of SOD1 and Acb1 into the extracellular space. The trafficking of these signal sequence lacking proteins therefore has functional similarities to conventional protein secretion in that they rely on membrane bounded compartments for their sorting and transport, but bypass the need of Sec61 for translocating into the ER and COPII and COPI for their intracellular transfers. This review is part of a Special Issue of SCDB on "unconventional protein secretion" edited by Walter Nickel and Catherine Rabouille.
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Affiliation(s)
- David Cruz-Garcia
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain.
| | - Vivek Malhotra
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain.
| | - Amy J Curwin
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain.
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113
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Grube L, Dellen R, Kruse F, Schwender H, Stühler K, Poschmann G. Mining the Secretome of C2C12 Muscle Cells: Data Dependent Experimental Approach To Analyze Protein Secretion Using Label-Free Quantification and Peptide Based Analysis. J Proteome Res 2018; 17:879-890. [DOI: 10.1021/acs.jproteome.7b00684] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Leonie Grube
- Molecular
Proteomics Laboratory, Biomedical Research Centre (BMFZ), Heinrich-Heine-University, Düsseldorf 40225, Germany
| | - Rafael Dellen
- Mathematical
Institute, Heinrich-Heine-University, Düsseldorf 40225, Germany
- Center for
Bioinformatics and Biostatistics, Biomedical Research Centre Heinrich-Heine-University, Düsseldorf 40225, Germany
| | - Fabian Kruse
- Molecular
Proteomics Laboratory, Biomedical Research Centre (BMFZ), Heinrich-Heine-University, Düsseldorf 40225, Germany
| | - Holger Schwender
- Mathematical
Institute, Heinrich-Heine-University, Düsseldorf 40225, Germany
- Center for
Bioinformatics and Biostatistics, Biomedical Research Centre Heinrich-Heine-University, Düsseldorf 40225, Germany
| | - Kai Stühler
- Molecular
Proteomics Laboratory, Biomedical Research Centre (BMFZ), Heinrich-Heine-University, Düsseldorf 40225, Germany
- Institute
for Molecular Medicine, University Hospital Düsseldorf, Düsseldorf 40225, Germany
| | - Gereon Poschmann
- Molecular
Proteomics Laboratory, Biomedical Research Centre (BMFZ), Heinrich-Heine-University, Düsseldorf 40225, Germany
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114
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New Interactors of the Truncated EBNA-LP Protein Identified by Mass Spectrometry in P3HR1 Burkitt's Lymphoma Cells. Cancers (Basel) 2018; 10:cancers10010012. [PMID: 29303964 PMCID: PMC5789362 DOI: 10.3390/cancers10010012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 12/21/2017] [Accepted: 12/21/2017] [Indexed: 01/07/2023] Open
Abstract
The Epstein-Barr virus nuclear antigen leader protein (EBNA-LP) acts as a co-activator of EBNA-2, a transcriptional activator essential for Epstein-Barr virus (EBV)-induced B-cell transformation. Burkitt's lymphoma (BL) cells harboring a mutant EBV strain that lacks both the EBNA-2 gene and 3' exons of EBNA-LP express Y1Y2-truncated isoforms of EBNA-LP (tEBNA-LP) and better resist apoptosis than if infected with the wild-type virus. In such BL cells, tEBNA-LP interacts with the protein phosphatase 2A (PP2A) catalytic subunit (PP2A C), and this interaction likely plays a role in resistance to apoptosis. Here, 28 cellular and four viral proteins have been identified by mass spectrometry as further possible interactors of tEBNA-LP. Three interactions were confirmed by immunoprecipitation and Western blotting, namely with the A structural subunit of PP2A (PP2A A), the structure-specific recognition protein 1 (SSRP1, a component of the facilitate chromatin transcription (FACT) complex), and a new form of the transcription factor EC (TFEC). Thus, tEBNA-LP appears to be involved not only in cell resistance to apoptosis through its interaction with two PP2A subunits, but also in other processes where its ability to co-activate transcriptional regulators could be important.
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115
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Crosstalk of Autophagy and the Secretory Pathway and Its Role in Diseases. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 337:153-184. [DOI: 10.1016/bs.ircmb.2017.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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116
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Villeneuve J, Bassaganyas L, Lepreux S, Chiritoiu M, Costet P, Ripoche J, Malhotra V, Schekman R. Unconventional secretion of FABP4 by endosomes and secretory lysosomes. J Cell Biol 2017; 217:649-665. [PMID: 29212659 PMCID: PMC5800802 DOI: 10.1083/jcb.201705047] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 10/09/2017] [Accepted: 11/14/2017] [Indexed: 01/30/2023] Open
Abstract
Adipocytes secrete fatty acid binding protein 4, which influences glucose production in hepatocytes and insulin secretion in pancreatic β-cells, but the mechanisms of its secretion are unclear. Villeneuve et al. show that FABP4 is secreted unconventionally through enclosure within endosomes and secretory lysosomes. An appreciation of the functional properties of the cytoplasmic fatty acid binding protein 4 (FABP4) has advanced with the recent demonstration that an extracellular form secreted by adipocytes regulates a wide range of physiological functions. Little, however, is known about the mechanisms that mediate the unconventional secretion of FABP4. Here, we demonstrate that FABP4 secretion is mediated by a membrane-bounded compartment, independent of the conventional endoplasmic reticulum–Golgi secretory pathway. We show that FABP4 secretion is also independent of GRASP proteins, autophagy, and multivesicular bodies but involves enclosure within endosomes and secretory lysosomes. We highlight the physiological significance of this pathway with the demonstration that an increase in plasma levels of FABP4 is inhibited by chloroquine treatment of mice. These findings chart the pathway of FABP4 secretion and provide a potential therapeutic means to control metabolic disorders associated with its dysregulated secretion.
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Affiliation(s)
- Julien Villeneuve
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA
| | - Laia Bassaganyas
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA.,Institute for Human Genetics, University of California, San Francisco, San Francisco, CA
| | - Sebastien Lepreux
- Institut National de la Santé et de la Recherche Médicale U1026, Université de Bordeaux, Bordeaux, France
| | - Marioara Chiritoiu
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Pierre Costet
- Service des Animaleries, Université de Bordeaux, Bordeaux, France
| | - Jean Ripoche
- Institut National de la Santé et de la Recherche Médicale U1026, Université de Bordeaux, Bordeaux, France
| | - Vivek Malhotra
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain .,Universitat Pompeu Fabra, Barcelona, Spain.,Institutio Catalana de Recerca i Estudis Avancats, Barcelona, Spain
| | - Randy Schekman
- Department of Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA
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117
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Huang S, Wang Y. Golgi structure formation, function, and post-translational modifications in mammalian cells. F1000Res 2017; 6:2050. [PMID: 29225785 PMCID: PMC5710388 DOI: 10.12688/f1000research.11900.1] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/20/2017] [Indexed: 01/04/2023] Open
Abstract
The Golgi apparatus is a central membrane organelle for trafficking and post-translational modifications of proteins and lipids in cells. In mammalian cells, it is organized in the form of stacks of tightly aligned flattened cisternae, and dozens of stacks are often linked laterally into a ribbon-like structure located in the perinuclear region of the cell. Proper Golgi functionality requires an intact architecture, yet Golgi structure is dynamically regulated during the cell cycle and under disease conditions. In this review, we summarize our current understanding of the relationship between Golgi structure formation, function, and regulation, with focus on how post-translational modifications including phosphorylation and ubiquitination regulate Golgi structure and on how Golgi unstacking affects its functions, in particular, protein trafficking, glycosylation, and sorting in mammalian cells.
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Affiliation(s)
- Shijiao Huang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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118
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Waldera-Lupa DM, Etemad-Parishanzadeh O, Brocksieper M, Kirchgaessler N, Seidel S, Kowalski T, Montesinos-Rongen M, Deckert M, Schlegel U, Stühler K. Proteomic changes in cerebrospinal fluid from primary central nervous system lymphoma patients are associated with protein ectodomain shedding. Oncotarget 2017; 8:110118-110132. [PMID: 29299134 PMCID: PMC5746369 DOI: 10.18632/oncotarget.22654] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 10/27/2017] [Indexed: 01/01/2023] Open
Abstract
Primary central nervous system lymphomas (PCNSLs) are mature B-cell lymphomas confined to the central nervous system (CNS). Blood-brain barrier (BBB) dysfunction drastically alters the cerebrospinal fluid (CSF) proteome in PCNSL patients. To reveal the interaction of PCNSL tumors with CNS structures and the vasculature, we conducted a whole-proteome analysis of CSF from PCNSL patients (n = 17 at initial diagnosis) and tumor-free controls (n = 10) using label-free quantitative mass spectrometry. We identified 601 proteins in the CSF proteome using a one-step approach without further prefractionation, and quantified 438 proteins in detail using the Hi-N method. An immunoassay revealed that 70% of the patients in our unselected PCNSL patient cohort had BBB dysfunction. Correlation analysis indicated that 127 (30%) of the quantified proteins were likely increased in PCSNL patients due to BBB dysfunction. After the exclusion of these proteins, 66 were found to differ in abundance (fold-change > 2.0, p < 0.05) between PCNSL and control CSF proteomes, and most of those were associated with the CNS. These data also provide the first evidence that proteomic changes in CSF from PCNSL patients are mainly associated with protein ectodomain shedding, and that shedding of human leukocyte antigen class 2 proteins is a mechanism of tumor-cell immune evasion.
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Affiliation(s)
- Daniel Michael Waldera-Lupa
- Molecular Proteomics Laboratory, Institute of Molecular Medicine, Universitaetsklinikum Düsseldorf, Düsseldorf, Germany
| | - Omid Etemad-Parishanzadeh
- Molecular Proteomics Laboratory, Institute of Molecular Medicine, Universitaetsklinikum Düsseldorf, Düsseldorf, Germany
| | - Mareike Brocksieper
- Molecular Proteomics Laboratory, Institute of Molecular Medicine, Universitaetsklinikum Düsseldorf, Düsseldorf, Germany
| | - Nina Kirchgaessler
- Molecular Proteomics Laboratory, Institute of Molecular Medicine, Universitaetsklinikum Düsseldorf, Düsseldorf, Germany
| | - Sabine Seidel
- Department of Neurology, Knappschaftskrankenhaus, Ruhr-University Bochum, Bochum, Germany
| | - Thomas Kowalski
- Department of Neurology, Knappschaftskrankenhaus, Ruhr-University Bochum, Bochum, Germany
| | | | - Martina Deckert
- Institute of Neuropathology, University of Cologne, Cologne, Germany
| | - Uwe Schlegel
- Department of Neurology, Knappschaftskrankenhaus, Ruhr-University Bochum, Bochum, Germany
| | - Kai Stühler
- Molecular Proteomics Laboratory, Institute of Molecular Medicine, Universitaetsklinikum Düsseldorf, Düsseldorf, Germany.,Biologisch-Medizinisches Forschungszentrum, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
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119
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Zhao XL, Lin Y, Jiang J, Tang Z, Yang S, Lu L, Liang Y, Liu X, Tan J, Hu XG, Niu Q, Fu WJ, Yan ZX, Guo DY, Ping YF, Wang JM, Zhang X, Kung HF, Bian XW, Yao XH. High-mobility group box 1 released by autophagic cancer-associated fibroblasts maintains the stemness of luminal breast cancer cells. J Pathol 2017; 243:376-389. [PMID: 28802057 DOI: 10.1002/path.4958] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 07/28/2017] [Accepted: 08/01/2017] [Indexed: 01/16/2023]
Abstract
Cancer stem cells/cancer-initiating cells (CICs) and their microenvironmental niche play a vital role in malignant tumour recurrence and metastasis. Cancer-associated fibroblasts (CAFs) are major components of the niche of breast cancer-initiating cells (BCICs), and their interactions may profoundly affect breast cancer progression. Autophagy has been considered to be a critical process for CIC maintenance, but whether it is involved in the cross-talk between CAFs and CICs to affect tumourigenesis and pathological significance has not been determined. In this study, we found that the presence of CAFs containing high levels of microtubule-associated protein 1 light chain 3 (LC3II), a marker of autophagosomes, was associated with more aggressive luminal human breast cancer. CAFs in human luminal breast cancer tissues with high autophagy activity enriched BCICs with increased tumourigenicity. Mechanistically, autophagic CAFs released high-mobility group box 1 (HMGB1), which activated its receptor, Toll-like receptor (TLR) 4, expressed by luminal breast cancer cells, to enhance their stemness and tumourigenicity. Furthermore, immunohistochemistry of 180 luminal breast cancers revealed that high LC3II/TLR4 levels predicted an increased relapse rate and a poorer prognosis. Our findings demonstrate that autophagic CAFs play a critical role in promoting the progression of luminal breast cancer through an HMGB1-TLR4 axis, and that both autophagy in CAFs and TLR4 on breast cancer cells constitute potential therapeutic targets. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Xi-Long Zhao
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Yong Lin
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Jun Jiang
- Breast Disease Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Zhuo Tang
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Shuai Yang
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Lu Lu
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Yan Liang
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China.,Breast Disease Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Xue Liu
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Jiao Tan
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Xu-Gang Hu
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Qin Niu
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Wen-Juan Fu
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Ze-Xuan Yan
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - De-Yu Guo
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Yi-Fang Ping
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Ji Ming Wang
- Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, USA
| | - Xia Zhang
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Hsiang-Fu Kung
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Xiu-Wu Bian
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
| | - Xiao-Hong Yao
- Institute of Pathology and Southwest Cancer Centre, Southwest Hospital, Third Military Medical University, Chongqing, PR China
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120
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Steringer JP, Nickel W. The molecular mechanism underlying unconventional secretion of Fibroblast Growth Factor 2 from tumour cells. Biol Cell 2017; 109:375-380. [PMID: 28799166 DOI: 10.1111/boc.201700036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/07/2017] [Accepted: 08/07/2017] [Indexed: 11/29/2022]
Abstract
Fibroblast Growth Factor 2 (FGF2) is a potent cell survival factor involved in tumour-induced angiogenesis. FGF2 is secreted from cells through an unconventional secretory mechanism based upon direct translocation across the plasma membrane. The molecular mechanism underlying this process depends on a surprisingly small set of trans-acting factors that are physically associated with the plasma membrane. FGF2 membrane translocation is mediated by the ability of FGF2 to oligomerise and to insert into the plasma membrane in a PI(4,5)P2 -dependent manner. Membrane-inserted FGF2 oligomers are dynamic translocation intermediates that are disassembled at the extracellular leaflet mediated by membrane proximal heparan sulphate proteoglycans. This process results in the exposure of FGF2 on cell surfaces as part of its unconventional mechanism of secretion. Although the trans-acting factors and cis-elements in FGF2 required for unconventional secretion have been known for a while, the core mechanism of this mysterious process has now been reconstituted with purified components establishing the molecular basis of FGF2 secretion from tumour cells.
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Affiliation(s)
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Heidelberg, Germany
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121
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Brough D, Pelegrin P, Nickel W. An emerging case for membrane pore formation as a common mechanism for the unconventional secretion of FGF2 and IL-1β. J Cell Sci 2017; 130:3197-3202. [PMID: 28871048 DOI: 10.1242/jcs.204206] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/20/2017] [Indexed: 12/12/2022] Open
Abstract
Extracellular proteins with important signalling roles in processes, such as inflammation and angiogenesis, are known to employ unconventional routes of protein secretion. Although mechanisms of unconventional protein secretion are beginning to emerge, the precise molecular details have remained elusive for the majority of cargo proteins secreted by unconventional means. Recent findings suggest that for two examples of unconventionally secreted proteins, interleukin 1β (IL-1β) and fibroblast growth factor 2 (FGF2), the common molecular principle of pore formation may be shared. Under specific experimental conditions, secretion of IL-1β and FGF2 is triggered by phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]-dependent formation of pores across the plasma membrane. However, the underlying mechanisms are different, with FGF2 known to directly interact with PI(4,5)P2, whereas in the case of IL-1β secretion, it is proposed that the N-terminal fragment of gasdermin D interacts with PI(4,5)P2 to form the pore. Thus, although implemented in different ways, these findings suggest that pore formation may be shared by the unconventional secretion mechanisms for FGF2 and IL-1β in at least some cases. In this Opinion article, we discuss the unconventional mechanisms of FGF2 and IL-1β release with a particular emphasis on recent discoveries suggesting the importance of pore formation on the plasma membrane.
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Affiliation(s)
- David Brough
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, M13 9PT, UK
| | - Pablo Pelegrin
- Grupo de Inflamación Molecular, Hospital Clínico Universitario Virgen de la Arrixaca, Instituto Murciano de Investigación Biosanitaria-Arrixaca (IMIB-Arrixaca), 30120 Murcia, Spain
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
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122
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Mutant Huntingtin Is Secreted via a Late Endosomal/Lysosomal Unconventional Secretory Pathway. J Neurosci 2017; 37:9000-9012. [PMID: 28821645 DOI: 10.1523/jneurosci.0118-17.2017] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 06/26/2017] [Accepted: 08/09/2017] [Indexed: 12/22/2022] Open
Abstract
Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder caused by the expansion of a CAG triplet in the gene encoding for huntingtin (Htt). The resulting mutant protein (mHtt) with extended polyglutamine (polyQ) sequence at the N terminus leads to neuronal degeneration both in a cell-autonomous and a non-cell-autonomous manner. Recent studies identified mHtt in the extracellular environment and suggested that its spreading contributes to toxicity, but the mechanism of mHtt release from the cell of origin remains unknown. In this study, we performed a comprehensive, unbiased analysis of secretory pathways and identified an unconventional lysosomal pathway as an important mechanism for mHtt secretion in mouse neuroblastoma and striatal cell lines, as well as in primary neurons. mHtt secretion was dependent on synaptotagmin 7, a regulator of lysosomal secretion, and inhibited by chemical ablation of late endosomes/lysosomes, suggesting a lysosomal secretory pattern. mHtt was targeted preferentially to the late endosomes/lysosomes compared with wild-type Htt. Importantly, we found that late endosomal/lysosomal targeting and secretion of mHtt could be inhibited efficiently by the phosphatidylinositol 3-kinase and neutral sphingomyelinase chemical inhibitors, Ly294002 and GW4869, respectively. Together, our data suggest a lysosomal mechanism of mHtt secretion and offer potential strategies for pharmacological modulation of its neuronal secretion.SIGNIFICANCE STATEMENT This is the first study examining the mechanism of mutant huntingtin (mHTT) secretion in an unbiased manner. We found that the protein is secreted via a late endosomal/lysosomal unconventional secretory pathway. Moreover, mHtt secretion can be reduced significantly by phosphatidylinositol 3-kinase and neutral sphingomyelinase inhibitors. Understanding and manipulating the secretion of mHtt is important because of its potentially harmful propagation in the brain.
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123
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Cruz-Garcia D, Brouwers N, Duran JM, Mora G, Curwin AJ, Malhotra V. A diacidic motif determines unconventional secretion of wild-type and ALS-linked mutant SOD1. J Cell Biol 2017; 216:2691-2700. [PMID: 28794127 PMCID: PMC5584182 DOI: 10.1083/jcb.201704056] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 06/28/2017] [Accepted: 07/27/2017] [Indexed: 01/08/2023] Open
Abstract
Starvation-induced unconventional secretion of Acb1 requires ESCRT-I, -II, and -III and Grh1. Cruz-Garcia et al. report that SOD1 and its mutant form linked to amyotrophic lateral sclerosis are also secreted upon nutrient starvation in a Grh1- and ESCRT-I–, -II–, and -III–dependent process. The authors identify a conserved diacidic motif in Acb1 and SOD1 that is necessary for their export in yeast and human cells. The nutrient starvation-specific unconventional secretion of Acb1 in Saccharomyces cerevisiae requires ESCRT-I, -II, and -III and Grh1. In this study, we report that another signal sequence lacking cytoplasmic protein, superoxide dismutase 1 (SOD1), and its mutant form linked to amyotrophic lateral sclerosis (ALS), is also secreted by yeast upon nutrient starvation in a Grh1- and ESCRT-I–, -II–, and -III–dependent process. Our analyses reveal that a conserved diacidic motif (Asp-Glu) in these proteins is necessary for their export. Importantly, secretion of wild-type human SOD1 and the ALS-linked mutant in human cells also require the diacidic residues. Altogether, these findings reveal information encoded within the cytoplasmic proteins required for their unconventional secretion and provide a means to unravel the significance of the cytoplasmic versus the secreted form of mutant SOD1 in the pathology of ALS. We also propose how cells, based on a signal-induced change in cytoplasmic physiology, select a small pool of a subset of cytoplasmic proteins for unconventional secretion.
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Affiliation(s)
- David Cruz-Garcia
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Nathalie Brouwers
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Juan M Duran
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Gabriel Mora
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Amy J Curwin
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - 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, Barcelona, Spain
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124
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Steringer JP, Lange S, Čujová S, Šachl R, Poojari C, Lolicato F, Beutel O, Müller HM, Unger S, Coskun Ü, Honigmann A, Vattulainen I, Hof M, Freund C, Nickel W. Key steps in unconventional secretion of fibroblast growth factor 2 reconstituted with purified components. eLife 2017; 6. [PMID: 28722655 PMCID: PMC5601999 DOI: 10.7554/elife.28985] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 07/14/2017] [Indexed: 12/31/2022] Open
Abstract
FGF2 is secreted from cells by an unconventional secretory pathway. This process is mediated by direct translocation across the plasma membrane. Here, we define the minimal molecular machinery required for FGF2 membrane translocation in a fully reconstituted inside-out vesicle system. FGF2 membrane translocation is thermodynamically driven by PI(4,5)P2-induced membrane insertion of FGF2 oligomers. The latter serve as dynamic translocation intermediates of FGF2 with a subunit number in the range of 8-12 FGF2 molecules. Vectorial translocation of FGF2 across the membrane is governed by sequential and mutually exclusive interactions with PI(4,5)P2 and heparan sulfates on opposing sides of the membrane. Based on atomistic molecular dynamics simulations, we propose a mechanism that drives PI(4,5)P2 dependent oligomerization of FGF2. Our combined findings establish a novel type of self-sustained protein translocation across membranes revealing the molecular basis of the unconventional secretory pathway of FGF2. DOI:http://dx.doi.org/10.7554/eLife.28985.001
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Affiliation(s)
| | - Sascha Lange
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Sabína Čujová
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Radek Šachl
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Chetan Poojari
- Department of Physics, University of Helsinki, Helsinki, Finland.,Department of Physics, Tampere University of Technology, Tampere, Finland
| | - Fabio Lolicato
- Department of Physics, University of Helsinki, Helsinki, Finland.,Department of Physics, Tampere University of Technology, Tampere, Finland
| | - Oliver Beutel
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | | | - Sebastian Unger
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Ünal Coskun
- Paul Langerhans Institute Dresden, Helmholtz Zentrum München, University Hospital and Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.,Deutsches Zentrum fur Diabetesforschung, Neuherberg, Germany
| | - Alf Honigmann
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Ilpo Vattulainen
- Department of Physics, University of Helsinki, Helsinki, Finland.,Department of Physics, Tampere University of Technology, Tampere, Finland.,MEMPHYS - Center for Biomembrane Physics, University of Southern Denmark, Denmark, United Kingdom
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Christian Freund
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Heidelberg, Germany
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125
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Ignashkova TI, Gendarme M, Peschk K, Eggenweiler HM, Lindemann RK, Reiling JH. Cell survival and protein secretion associated with Golgi integrity in response to Golgi stress-inducing agents. Traffic 2017; 18:530-544. [PMID: 28485883 DOI: 10.1111/tra.12493] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 05/05/2017] [Accepted: 05/05/2017] [Indexed: 12/29/2022]
Abstract
The Golgi apparatus is part of the secretory pathway and of central importance for modification, transport and sorting of proteins and lipids. ADP-ribosylation factors, whose activation can be blocked by brefeldin A (BFA), play a major role in functioning of the Golgi network and regulation of membrane traffic and are also involved in proliferation and migration of cancer cells. Due to high cytotoxicity and poor bioavailability, BFA has not passed the preclinical stage of drug development. Recently, AMF-26 and golgicide A have been described as novel inhibitors of the Golgi system with antitumor or bactericidal properties. We provide here further evidence that AMF-26 closely mirrors the mode of action of BFA but is less potent. Using several human cancer cell lines, we studied the effects of AMF-26, BFA and golgicide A on cell homeostasis including Golgi structure, endoplasmic reticulum (ER) stress markers, secretion and viability, and found overall a significant correlation between these parameters. Furthermore, modulation of ADP-ribosylation factor expression has a profound impact on Golgi organization and survival in response to Golgi stress inducers.
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Affiliation(s)
- Tatiana I Ignashkova
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Heidelberg, Germany
| | - Mathieu Gendarme
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Heidelberg, Germany
| | - Katrin Peschk
- Medicinal Chemistry, Merck Biopharma, Merck KGaA, Darmstadt, Germany
| | | | - Ralph K Lindemann
- Translational Innovation Platform Oncology, Merck Biopharma, Merck KGaA, Darmstadt, Germany
| | - Jan H Reiling
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Heidelberg, Germany
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126
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127
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Liu W, Hajjar KA. The annexin A2 system and angiogenesis. Biol Chem 2017; 397:1005-16. [PMID: 27366903 DOI: 10.1515/hsz-2016-0166] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/28/2016] [Indexed: 01/23/2023]
Abstract
The formation of new blood vessels from pre-existing vasculature, the process known as angiogenesis, is highly regulated by pro- and anti-angiogenic signaling molecules including growth factors and proteases. As an endothelial cell-surface co-receptor for plasminogen and tissue plasminogen activator, the annexin A2 (ANXA2) complex accelerates plasmin generation and facilitates fibrinolysis. Plasmin can subsequently activate a downstream proteolytic cascade involving multiple matrix metalloproteinases. Thus, in addition to maintaining blood vessel patency, the ANXA2 complex can also promote angiogenesis via its pro-fibrinolytic activity. The generation of ANXA2-deficient mice allowed us to first observe the pro-angiogenic role of ANXA2 in vivo. Further investigations have provided additional details regarding the mechanism for ANXA2 regulation of retinal and corneal angiogenesis. Other studies have reported that ANXA2 supports angiogenesis in specific tumor-related settings. Here, we summarize results from in vivo studies that illustrate the pro-angiogenic role of ANXA2, and discuss the critical questions that may lead to an advanced understanding of the molecular mechanisms for ANXA2-mediated angiogenesis. Finally, highlights from studies on ANXA2-interacting agents offer potential therapeutic opportunities for the application of ANXA2-centered pharmaceuticals in angiogenesis-related disorders.
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128
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Horigome T, Takumi S, Shirai K, Kido T, Hagiwara-Chatani N, Nakashima A, Adachi N, Yano H, Hirai Y. Sulfated glycosaminoglycans and non-classically secreted proteins, basic FGF and epimorphin, coordinately regulate TGF-β-induced cell behaviors of human scar dermal fibroblasts. J Dermatol Sci 2017; 86:132-141. [DOI: 10.1016/j.jdermsci.2017.01.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/16/2017] [Accepted: 01/31/2017] [Indexed: 12/15/2022]
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129
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Applying Unconventional Secretion in Ustilago maydis for the Export of Functional Nanobodies. Int J Mol Sci 2017; 18:ijms18050937. [PMID: 28468279 PMCID: PMC5454850 DOI: 10.3390/ijms18050937] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/21/2017] [Accepted: 04/24/2017] [Indexed: 12/25/2022] Open
Abstract
Exploiting secretory pathways for production of heterologous proteins is highly advantageous with respect to efficient downstream processing. In eukaryotic systems the vast majority of heterologous proteins for biotechnological application is exported via the canonical endoplasmic reticulum–Golgi pathway. In the endomembrane system target proteins are often glycosylated and may thus be modified with foreign glycan patterns. This can be destructive for their activity or cause immune reactions against therapeutic proteins. Hence, using unconventional secretion for protein expression is an attractive alternative. In the fungal model Ustilago maydis, chitinase Cts1 is secreted via an unconventional pathway connected to cell separation which can be used to co-export heterologous proteins. Here, we apply this mechanism for the production of nanobodies. First, we achieved expression and unconventional secretion of a functional nanobody directed against green fluorescent protein (Gfp). Second, we found that Cts1 binds to chitin and that this feature can be applied to generate a Gfp-trap. Thus, we demonstrated the dual use of Cts1 serving both as export vehicle and as purification tag. Finally, we established and optimized the production of a nanobody against botulinum toxin A and hence describe the first pharmaceutically relevant target exported by Cts1-mediated unconventional secretion.
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130
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Lorey MB, Rossi K, Eklund KK, Nyman TA, Matikainen S. Global Characterization of Protein Secretion from Human Macrophages Following Non-canonical Caspase-4/5 Inflammasome Activation. Mol Cell Proteomics 2017; 16:S187-S199. [PMID: 28196878 DOI: 10.1074/mcp.m116.064840] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 02/01/2017] [Indexed: 12/27/2022] Open
Abstract
Gram-negative bacteria are associated with a wide spectrum of infectious diseases in humans. Inflammasomes are cytosolic protein complexes that are assembled when the cell encounters pathogens or other harmful agents. The non-canonical caspase-4/5 inflammasome is activated by Gram-negative bacteria-derived lipopolysaccharide (LPS) and by endogenous oxidized phospholipids. Protein secretion is a critical component of the innate immune response. Here, we have used label-free quantitative proteomics to characterize global protein secretion in response to non-canonical inflammasome activation upon intracellular LPS recognition in human primary macrophages. Before proteomics, the total secretome was separated into two fractions, enriched extracellular vesicle (EV) fraction and rest-secretome (RS) fraction using size-exclusion centrifugation. We identified 1048 proteins from the EV fraction and 1223 proteins from the RS fraction. From these, 640 were identified from both fractions suggesting that the non-canonical inflammasome activates multiple, partly overlapping protein secretion pathways. We identified several secreted proteins that have a critical role in host response against severe Gram-negative bacterial infection. The soluble secretome (RS fraction) was highly enriched with inflammation-associated proteins upon intracellular LPS recognition. Several ribosomal proteins were highly abundant in the EV fraction upon infection, and our data strongly suggest that secretion of translational machinery and concomitant inhibition of translation are important parts of host response against Gram-negative bacteria sensing caspase-4/5 inflammasome. Intracellular recognition of LPS resulted in the secretion of two metalloproteinases, adisintegrin and metalloproteinase domain-containing protein 10 (ADAM10) and MMP14, in the enriched EV fraction. ADAM10 release was associated with the secretion of TNF, a key inflammatory cytokine, and M-CSF, an important growth factor for myeloid cells probably through ADAM10-dependent membrane shedding of these cytokines. Caspase-4/5 inflammasome activation also resulted in secretion of danger-associated molecules S100A8 and prothymosin-α in the enriched EV fraction. Both S100A8 and prothymosin-α are ligands for toll-like receptor 4 recognizing extracellular LPS, and they may contribute to endotoxic shock during non-canonical inflammasome activation.
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Affiliation(s)
- Martina B Lorey
- From the ‡Rheumatology, University of Helsinki and Helsinki University Hospital, 00290 Helsinki, Finland
| | - Katriina Rossi
- From the ‡Rheumatology, University of Helsinki and Helsinki University Hospital, 00290 Helsinki, Finland
| | - Kari K Eklund
- From the ‡Rheumatology, University of Helsinki and Helsinki University Hospital, 00290 Helsinki, Finland
| | - Tuula A Nyman
- §Department of Immunology, Institute of Clinical Medicine, University of Oslo and Rikshospitalet Oslo, Oslo 0424, Norway
| | - Sampsa Matikainen
- From the ‡Rheumatology, University of Helsinki and Helsinki University Hospital, 00290 Helsinki, Finland
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131
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Araujo TLS, Zeidler JD, Oliveira PVS, Dias MH, Armelin HA, Laurindo FRM. Protein disulfide isomerase externalization in endothelial cells follows classical and unconventional routes. Free Radic Biol Med 2017; 103:199-208. [PMID: 28034831 DOI: 10.1016/j.freeradbiomed.2016.12.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 12/09/2016] [Accepted: 12/17/2016] [Indexed: 12/22/2022]
Abstract
Extracellular protein disulfide isomerase (PDIA1) pool mediates thrombosis and vascular remodeling, however its externalization mechanisms remain unclear. We performed systematic pharmacological screening of secretory pathways affecting extracellular PDIA1 in endothelial cells (EC). We identified cell-surface (csPDIA1) and secreted non-particulated PDIA1 pools in EC. Such Golgi bypass also occurred for secreted PDIA1 in EC at baseline or after PMA, thrombin or ATP stimulation. Inhibitors of Type I, II and III unconventional routes, secretory lysosomes and recycling endosomes, including syntaxin-12 deletion, did not impair EC PDIA1 externalization. This suggests predominantly Golgi-independent unconventional secretory route(s), which were GRASP55-independent. Also, these data reinforce a vesicular-type traffic for PDIA1. We further showed that PDIA1 traffic is ATP-independent, while actin or tubulin cytoskeletal disruption markedly increased EC PDIA1 secretion. Clathrin inhibition enhanced extracellular soluble PDIA1, suggesting dynamic cycling. Externalized PDIA1 represents <2% of intracellular PDIA1. PDIA1 was robustly secreted by physiological levels of arterial laminar shear in EC and supported alpha 5 integrin thiol oxidation. Such results help clarify signaling and homeostatic mechanisms involved in multiple (patho)physiological extracellular PDIA1 functions.
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Affiliation(s)
- Thaís L S Araujo
- Vascular Biology Laboratory, Heart Institute (InCor), University of São Paulo School of Medicine, São Paulo 05403-000, Brazil
| | - Julianna D Zeidler
- Vascular Biology Laboratory, Heart Institute (InCor), University of São Paulo School of Medicine, São Paulo 05403-000, Brazil
| | - Percíllia V S Oliveira
- Vascular Biology Laboratory, Heart Institute (InCor), University of São Paulo School of Medicine, São Paulo 05403-000, Brazil
| | - Matheus H Dias
- Instituto de Química, Universidade de São Paulo, Brazil; Laboratório Especial de Ciclo Celular (LECC), Center of Toxins, Immune-Response and Cell Signaling - CeTICS-Cepid, Instituto Butantan, Brazil
| | - Hugo A Armelin
- Instituto de Química, Universidade de São Paulo, Brazil; Laboratório Especial de Ciclo Celular (LECC), Center of Toxins, Immune-Response and Cell Signaling - CeTICS-Cepid, Instituto Butantan, Brazil
| | - Francisco R M Laurindo
- Vascular Biology Laboratory, Heart Institute (InCor), University of São Paulo School of Medicine, São Paulo 05403-000, Brazil.
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132
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Borland H, Vilhardt F. Prelysosomal Compartments in the Unconventional Secretion of Amyloidogenic Seeds. Int J Mol Sci 2017; 18:ijms18010227. [PMID: 28124989 PMCID: PMC5297856 DOI: 10.3390/ijms18010227] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/09/2017] [Accepted: 01/16/2017] [Indexed: 12/18/2022] Open
Abstract
A mechanistic link between neuron-to-neuron transmission of secreted amyloid and propagation of protein malconformation cytopathology and disease has recently been uncovered in animal models. An enormous interest in the unconventional secretion of amyloids from neurons has followed. Amphisomes and late endosomes are the penultimate maturation products of the autophagosomal and endosomal pathways, respectively, and normally fuse with lysosomes for degradation. However, under conditions of perturbed membrane trafficking and/or lysosomal deficiency, prelysosomal compartments may instead fuse with the plasma membrane to release any contained amyloid. After a brief introduction to the endosomal and autophagosomal pathways, we discuss the evidence for autophagosomal secretion (exophagy) of amyloids, with a comparative emphasis on Aβ1-42 and α-synuclein, as luminal and cytosolic amyloids, respectively. The ESCRT-mediated import of cytosolic amyloid into late endosomal exosomes, a known vehicle of transmission of macromolecules between cells, is also reviewed. Finally, mechanisms of lysosomal dysfunction, deficiency, and exocytosis are exemplified in the context of genetically identified risk factors, mainly for Parkinson's disease. Exocytosis of prelysosomal or lysosomal organelles is a last resort for clearance of cytotoxic material and alleviates cytopathy. However, they also represent a vehicle for the concentration, posttranslational modification, and secretion of amyloid seeds.
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Affiliation(s)
- Helena Borland
- Department of Neurodegeneration In Vitro, H. Lundbeck A/S, 2500 Valby, Denmark.
| | - Frederik Vilhardt
- Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, 2200N Copenhagen, Denmark.
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133
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Daniels MJD, Brough D. Unconventional Pathways of Secretion Contribute to Inflammation. Int J Mol Sci 2017; 18:E102. [PMID: 28067797 PMCID: PMC5297736 DOI: 10.3390/ijms18010102] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 12/16/2016] [Accepted: 12/30/2016] [Indexed: 12/13/2022] Open
Abstract
In the conventional pathway of protein secretion, leader sequence-containing proteins leave the cell following processing through the endoplasmic reticulum (ER) and Golgi body. However, leaderless proteins also enter the extracellular space through mechanisms collectively known as unconventional secretion. Unconventionally secreted proteins often have vital roles in cell and organism function such as inflammation. Amongst the best-studied inflammatory unconventionally secreted proteins are interleukin (IL)-1β, IL-1α, IL-33 and high-mobility group box 1 (HMGB1). In this review we discuss the current understanding of the unconventional secretion of these proteins and highlight future areas of research such as the role of nuclear localisation.
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Affiliation(s)
- Michael J D Daniels
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, AV Hill Building, Oxford Road, Manchester M13 9PT, UK.
| | - David Brough
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, AV Hill Building, Oxford Road, Manchester M13 9PT, UK.
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134
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Ding Y, Wang J. Analysis of Exocyst-Positive Organelle (EXPO)-Mediated Unconventional Protein Secretion (UPS) in Plant Cells. Methods Mol Biol 2017; 1662:231-241. [PMID: 28861833 DOI: 10.1007/978-1-4939-7262-3_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Unconventional protein secretion (UPS) together with conventional protein secretion (CPS) is responsible for protein secretion in plants. We have previously identified a novel UPS pathway in plants, which is mediated by exocyst-positive organelle-EXPO. Here, we describe detailed protocols to study UPS in plants by using Arabidopsis protoplasts or transgenic suspension cells, expressing the EXPO marker Exo70E2-XFP, as materials. Via drug and osmotic treatment plus secretion assay, we illustrate several major methods to analyze EXPO-mediated UPS in plant cells, which also supplys mining tools for similar study.
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Affiliation(s)
- Yu Ding
- Department of Food Science & Engineering, College of Science and Engineering, Jinan University, Guangzhou, 510632, China.
| | - Juan Wang
- College of Food Science, South China Agricultural University, Guangzhou, 510642, China.
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135
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Rabouille C. Pathways of Unconventional Protein Secretion. Trends Cell Biol 2016; 27:230-240. [PMID: 27989656 DOI: 10.1016/j.tcb.2016.11.007] [Citation(s) in RCA: 363] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/14/2016] [Accepted: 11/15/2016] [Indexed: 01/02/2023]
Abstract
Secretory proteins are conventionally transported through the endoplasmic reticulum to the Golgi and then to the plasma membrane where they are released into the extracellular space. However, numerous substrates also reach these destinations using unconventional pathways. Unconventional protein secretion (UPS) is complex and comprises cargos without a signal peptide or a transmembrane domain that can translocate across the plasma membrane, and cargos that reach the plasma membrane by bypassing the Golgi despite entering the endoplasmic reticulum (ER). With a few exceptions, unconventional secretion is largely triggered by stress. Here I review new results and concepts that are beginning to define these pathways.
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Affiliation(s)
- Catherine Rabouille
- Hubrecht Institute of the KNAW and UMC Utrecht, Utrecht, The Netherlands; Department of Cell Biology, UMC Utrecht, Utrecht, The Netherlands; Department of Cell Biology, UMC Groningen, Groningen, The Netherlands.
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136
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Keulers TG, Schaaf MBE, Rouschop KMA. Autophagy-Dependent Secretion: Contribution to Tumor Progression. Front Oncol 2016; 6:251. [PMID: 27933272 PMCID: PMC5122571 DOI: 10.3389/fonc.2016.00251] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 11/10/2016] [Indexed: 12/14/2022] Open
Abstract
Autophagy is best known as a lysosomal degradation and recycling pathway to maintain cellular homeostasis. During autophagy, cytoplasmic content is recognized and packed in autophagic vacuoles, or autophagosomes, and targeted for degradation. However, during the last years, it has become evident that the role of autophagy is not restricted to degradation alone but also mediates unconventional forms of secretion. Furthermore, cells with defects in autophagy apparently are able to reroute their cargo, like mitochondria, to the extracellular environment; effects that contribute to an array of pathologies. In this review, we discuss the current knowledge of the physiological roles of autophagy-dependent secretion, i.e., the effect on inflammation and insulin/hormone secretion. Finally, we focus on the effects of autophagy-dependent secretion on the tumor microenvironment (TME) and tumor progression. The autophagy-mediated secreted factors may stimulate cellular proliferation via auto- and paracrine signaling. The autophagy-mediated release of immune modulating proteins changes the immunosuppresive TME and may promote an invasive phenotype. These effects may be either direct or indirect through facilitating formation of the mobilized vesicle, aid in anterograde trafficking, or alterations in homeostasis and/or autonomous cell signaling.
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Affiliation(s)
- Tom G Keulers
- Maastricht Radiation Oncology (MaastRO) Lab, GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center , Maastricht , Netherlands
| | - Marco B E Schaaf
- Cell Death Research and Therapy (CDRT) Laboratory, Department Cellular and Molecular Medicine, KU Leuven, University of Leuven , Leuven , Belgium
| | - Kasper M A Rouschop
- Maastricht Radiation Oncology (MaastRO) Lab, GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center , Maastricht , Netherlands
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137
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Klement E, Medzihradszky KF. Extracellular Protein Phosphorylation, the Neglected Side of the Modification. Mol Cell Proteomics 2016; 16:1-7. [PMID: 27834735 DOI: 10.1074/mcp.o116.064188] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 11/10/2016] [Indexed: 12/18/2022] Open
Abstract
The very existence of extracellular phosphorylation has been questioned for a long time, although casein phosphorylation was discovered a century ago. In addition, several modification sites localized on secreted proteins or on extracellular or lumenal domains of transmembrane proteins have been catalogued in large scale phosphorylation analyses, though in most such studies this aspect of cellular localization was not considered. Our review presents examples when additional analyses were performed on already public data sets that revealed a wealth of information about this "neglected side" of the modification. We also sum up accumulated knowledge about extracellular phosphorylation, including the discovery of Golgi-residing kinases and the special difficulties encountered in targeted analyses. We hope future phosphorylation studies will not ignore the existence of phosphorylation outside of the cell, and further discoveries will shed more light on its biological role.
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Affiliation(s)
- Eva Klement
- From the ‡Laboratory of Proteomics Research, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary, and
| | - Katalin F Medzihradszky
- From the ‡Laboratory of Proteomics Research, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary, and .,the §Department of Pharmaceutical Chemistry, School of Pharmacy, University of California San Francisco, San Francisco, California
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138
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Nafar F, Williams JB, Mearow KM. Astrocytes release HspB1 in response to amyloid-β exposure in vitro. J Alzheimers Dis 2016; 49:251-63. [PMID: 26444769 DOI: 10.3233/jad-150317] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Although heat shock proteins are thought to function primarily as intracellular chaperones, the release and potential extracellular functions of heat shock proteins have been the focus of an increasing number of studies. Our particular interest is HspB1 (Hsp25/27) and as astrocytes are an in vivo source of HspB1 it is a reasonable possibility they could release HspB1 in response to local stresses. Using primary cultures of rat cortical astrocytes, we investigated the extracellular release of HspB1 with exposure to amyloid-β (Aβ). In order to assess potential mechanisms of release, we cotreated the cells with compounds that can modulate protein secretion including Brefeldin A, Methyl β-cyclodextrin, and MAP kinase inhibitors. Exposure to Aβ (0.1, 1.0, 2.0 μM) for 24-48 h resulted in a selective release of HspB1 that was insensitive to BFA treatment; none of the other inhibitors had any detectable influence. Protease protection assays indicated that some of the released HspB1 was associated with a membrane bound fraction, and analysis of exosomal preparations indicated the presence of HspB1 in exosomes. Finally, immunoprecipitation experiments demonstrated that the extracellular HspB1 was able to interact with extracellular Aβ. In summary, Aβ can stimulate release of HspB1 from astrocytes, this release is insensitive to Golgi or lipid raft disruption, and HspB1 can be found either free in the medium or associated with exosomes. This release suggests that there is a potential for extracellular HspB1 to be able to bind and sequester extracellular Aβ.
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139
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P2X7 receptor-mediated TG2 externalization: a link to inflammatory arthritis? Amino Acids 2016; 49:453-460. [PMID: 27562793 PMCID: PMC5332493 DOI: 10.1007/s00726-016-2319-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 08/18/2016] [Indexed: 12/15/2022]
Abstract
Transglutaminases have important roles in stabilizing extracellular protein assemblies in tissue repair processes but some reaction products can stimulate immune activation, leading to chronic inflammatory conditions or autoimmunity. Exacerbated disease in models of inflammatory arthritis has been ascribed to sustained extracellular enzyme activity alongside formation of select protein modifications. Here, we review the evidence, with a focus on the link between P2X7R signaling and TG2 export, a pathway that we have recently discovered which ties extracellular protein modifications into the danger signal-mediated innate immune response. These recent insights offer new opportunities for therapeutic intervention.
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140
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Adolf A, Leondaritis G, Rohrbeck A, Eickholt BJ, Just I, Ahnert-Hilger G, Höltje M. The intermediate filament protein vimentin is essential for axonotrophic effects of Clostridium botulinum C3 exoenzyme. J Neurochem 2016; 139:234-244. [PMID: 27419376 DOI: 10.1111/jnc.13739] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/24/2016] [Accepted: 07/12/2016] [Indexed: 01/01/2023]
Abstract
The type III intermediate filament protein vimentin was recently identified to mediate binding and uptake of Clostridium botulinum C3 exoenzyme (C3bot) in two cell lines. Here, we used primary neuronal cultures from vimentin knockout (Vim-/- ) mice to study the impact of vimentin on axonal growth and internalization of C3bot. In contrast to wild type, vimentin knockout neurons were insensitive to C3bot. Application of extracellular vimentin to Vim-/- neurons completely restored the growth-promoting effects of C3bot. In line with this uptake of C3bot into Vim-/- neurons was strongly decreased resulting in reduced ADP-ribosylation of RhoA and B as detected by an antibody recognizing selectively ADP-ribosylated RhoA/B. Again, uptake of C3bot into Vim-/- neurons was rescued by addition of extracellular vimentin. In addition, in purified embryonic stem cell-derived motor neurons that are devoid of glial cells C3bot elicited axonotrophic effects confining neuronal vimentin as a binding partner. Primary neuronal cultures from vimentin knockout (KO) mice were used to study the impact of vimentin on axonal growth and internalization of C3bot. In contrast to wild type, vimentin knockout neurons were insensitive to the axonotrophic effects of C3bot. Application of extracellular vimentin (recombinant vimentin) to vimentin KO neurons completely restored the growth-promoting effects of C3bot. In line with this uptake of C3bot into vimentin KO neurons was strongly decreased resulting in reduced ADP-ribosylation of RhoA and B as detected by an antibody recognizing selectively ADP-ribosylated RhoA/B.
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Affiliation(s)
- Andrej Adolf
- Institute of Integrative Neuroanatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - George Leondaritis
- Department of Pharmacology, Medical School, University of Ioannina, Ioannina, Greece
| | - Astrid Rohrbeck
- Institute of Toxicology, Hannover Medical School (MHH), Hannover, Germany
| | - Britta Johanna Eickholt
- Institute of Biochemistry & Neuro Cure Cluster of Excellence, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ingo Just
- Institute of Toxicology, Hannover Medical School (MHH), Hannover, Germany
| | - Gudrun Ahnert-Hilger
- Institute of Integrative Neuroanatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Markus Höltje
- Institute of Integrative Neuroanatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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141
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Batulan Z, Pulakazhi Venu VK, Li Y, Koumbadinga G, Alvarez-Olmedo DG, Shi C, O'Brien ER. Extracellular Release and Signaling by Heat Shock Protein 27: Role in Modifying Vascular Inflammation. Front Immunol 2016; 7:285. [PMID: 27507972 PMCID: PMC4960997 DOI: 10.3389/fimmu.2016.00285] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 07/14/2016] [Indexed: 12/31/2022] Open
Abstract
Heat shock protein 27 (HSP27) is traditionally viewed as an intracellular chaperone protein with anti-apoptotic properties. However, recent data indicate that a number of heat shock proteins, including HSP27, are also found in the extracellular space where they may signal via membrane receptors to alter gene transcription and cellular function. Therefore, there is increasing interest in better understanding how HSP27 is released from cells, its levels and composition in the extracellular space, and the cognate cell membrane receptors involved in effecting cell signaling. In this paper, the knowledge to date, as well as some emerging paradigms about the extracellular function of HSP27 is presented. Of particular interest is the role of HSP27 in attenuating atherogenesis by modifying lipid uptake and inflammation in the plaque. Moreover, the abundance of HSP27 in serum is an emerging new biomarker for ischemic events. Finally, HSP27 replacement therapy may represent a novel therapeutic opportunity for chronic inflammatory disorders, such as atherosclerosis.
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Affiliation(s)
- Zarah Batulan
- Vascular Biology Laboratory, Health Research Innovation Centre, Libin Cardiovascular Institute of Alberta, University of Calgary Cumming School of Medicine , Calgary, AB , Canada
| | - Vivek Krishna Pulakazhi Venu
- Vascular Biology Laboratory, Health Research Innovation Centre, Libin Cardiovascular Institute of Alberta, University of Calgary Cumming School of Medicine , Calgary, AB , Canada
| | - Yumei Li
- Vascular Biology Laboratory, Health Research Innovation Centre, Libin Cardiovascular Institute of Alberta, University of Calgary Cumming School of Medicine , Calgary, AB , Canada
| | - Geremy Koumbadinga
- Vascular Biology Laboratory, Health Research Innovation Centre, Libin Cardiovascular Institute of Alberta, University of Calgary Cumming School of Medicine , Calgary, AB , Canada
| | - Daiana Gisela Alvarez-Olmedo
- Oncology Laboratory, Institute for Experimental Medicine and Biology of Cuyo (IMBECU), CCT CONICET , Mendoza , Argentina
| | - Chunhua Shi
- Vascular Biology Laboratory, Health Research Innovation Centre, Libin Cardiovascular Institute of Alberta, University of Calgary Cumming School of Medicine , Calgary, AB , Canada
| | - Edward R O'Brien
- Vascular Biology Laboratory, Health Research Innovation Centre, Libin Cardiovascular Institute of Alberta, University of Calgary Cumming School of Medicine , Calgary, AB , Canada
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142
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La Venuta G, Wegehingel S, Sehr P, Müller HM, Dimou E, Steringer JP, Grotwinkel M, Hentze N, Mayer MP, Will DW, Uhrig U, Lewis JD, Nickel W. Small Molecule Inhibitors Targeting Tec Kinase Block Unconventional Secretion of Fibroblast Growth Factor 2. J Biol Chem 2016; 291:17787-803. [PMID: 27382052 DOI: 10.1074/jbc.m116.729384] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Indexed: 11/06/2022] Open
Abstract
Fibroblast growth factor 2 (FGF2) is a potent mitogen promoting both tumor cell survival and tumor-induced angiogenesis. It is secreted by an unconventional secretory mechanism that is based upon direct translocation across the plasma membrane. Key steps of this process are (i) phosphoinositide-dependent membrane recruitment, (ii) FGF2 oligomerization and membrane pore formation, and (iii) extracellular trapping mediated by membrane-proximal heparan sulfate proteoglycans. Efficient secretion of FGF2 is supported by Tec kinase that stimulates membrane pore formation based upon tyrosine phosphorylation of FGF2. Here, we report the biochemical characterization of the direct interaction between FGF2 and Tec kinase as well as the identification of small molecules that inhibit (i) the interaction of FGF2 with Tec, (ii) tyrosine phosphorylation of FGF2 mediated by Tec in vitro and in a cellular context, and (iii) unconventional secretion of FGF2 from cells. We further demonstrate the specificity of these inhibitors for FGF2 because tyrosine phosphorylation of a different substrate of Tec is unaffected in their presence. Building on previous evidence using RNA interference, the identified compounds corroborate the role of Tec kinase in unconventional secretion of FGF2. In addition, they are valuable lead compounds with great potential for drug development aiming at the inhibition of FGF2-dependent tumor growth and metastasis.
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Affiliation(s)
- Giuseppe La Venuta
- From the Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Sabine Wegehingel
- From the Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Peter Sehr
- the European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany, and
| | - Hans-Michael Müller
- From the Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Eleni Dimou
- From the Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Julia P Steringer
- From the Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Mareike Grotwinkel
- From the Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Nikolai Hentze
- the Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Matthias P Mayer
- the Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - David W Will
- the European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany, and
| | - Ulrike Uhrig
- the European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany, and
| | - Joe D Lewis
- the European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany, and
| | - Walter Nickel
- From the Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany,
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143
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Lopez V, Cauvi DM, Arispe N, De Maio A. Bacterial Hsp70 (DnaK) and mammalian Hsp70 interact differently with lipid membranes. Cell Stress Chaperones 2016; 21:609-16. [PMID: 27075190 PMCID: PMC4907991 DOI: 10.1007/s12192-016-0685-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 10/22/2022] Open
Abstract
The cellular response to stress is orchestrated by the expression of a family of proteins termed heat shock proteins (hsp) that are involved in the stabilization of basic cellular processes to preserve cell viability and homeostasis. The bulk of hsp function occurs within the cytosol and subcellular compartments. However, some hsp have also been found outside cells released by an active mechanism independent of cell death. Extracellular hsp act as signaling molecules directed at activating a systemic response to stress. The export of hsp requires the translocation from the cytosol into the extracellular milieu across the plasma membrane. We have proposed that membrane insertion is the initial step in this export process. We investigated the interaction of the major inducible hsp from mammalian (Hsp70) and bacterial (DnaK) species with liposomes. We found that mammalian Hsp70 displayed a high specificity for negatively charged phospholipids, such as phosphatidyl serine, whereas DnaK interacted with all lipids tested regardless of the charge. Both proteins were inserted into the lipid bilayer as demonstrated by resistance to acid or basic washes that was confirmed by partial protection from proteolytic cleavage. Several regions of mammalian Hsp70 were inserted into the membrane with a small portion of the N-terminus end exposed to the outer phase of the liposome. In contrast, the N-terminus end of DnaK was inserted into the membrane, exposing the C-terminus end outside the liposome. Mammalian Hsp70 was found to make high oligomeric complexes upon insertion into the membranes whereas DnaK only formed dimers within the lipid bilayer. These observations suggest that both Hsp70s interact with lipids, but mammalian Hsp70 displays a high degree of specificity and structure as compared with the bacterial form.
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Affiliation(s)
- Victor Lopez
- Initiative for Maximizing Student Development (IMSD) Program, La Jolla, CA, USA
| | - David M Cauvi
- Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | | | - Antonio De Maio
- Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, USA.
- Center for Investigations of Health and Education Disparities, La Jolla, CA, USA.
- Department of Neuroscience, School of Medicine, University of California San Diego, La Jolla, CA, USA.
- University of California San Diego, 9500 Gilman Drive, #0739, La Jolla, CA, 92093-0739, USA.
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144
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Lee JG, Takahama S, Zhang G, Tomarev SI, Ye Y. Unconventional secretion of misfolded proteins promotes adaptation to proteasome dysfunction in mammalian cells. Nat Cell Biol 2016; 18:765-76. [PMID: 27295555 PMCID: PMC10701763 DOI: 10.1038/ncb3372] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 05/11/2016] [Indexed: 12/14/2022]
Abstract
To safeguard proteomic integrity, cells rely on the proteasome to degrade aberrant polypeptides, but it is unclear how cells remove defective proteins that have escaped degradation owing to proteasome insufficiency or dysfunction. Here we report a pathway termed misfolding-associated protein secretion, which uses the endoplasmic reticulum (ER)-associated deubiquitylase USP19 to preferentially export aberrant cytosolic proteins. Intriguingly, the catalytic domain of USP19 possesses an unprecedented chaperone activity, allowing recruitment of misfolded proteins to the ER surface for deubiquitylation. Deubiquitylated cargos are encapsulated into ER-associated late endosomes and secreted to the cell exterior. USP19-deficient cells cannot efficiently secrete unwanted proteins, and grow more slowly than wild-type cells following exposure to a proteasome inhibitor. Together, our findings delineate a protein quality control (PQC) pathway that, unlike degradation-based PQC mechanisms, promotes protein homeostasis by exporting misfolded proteins through an unconventional protein secretion process.
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Affiliation(s)
- Jin-Gu Lee
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Shokichi Takahama
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
- Present address: Matsushita Project Laboratory, Center for AIDS Research, Kumamoto University, Kumamoto 860-0811, Japan
| | - Guofeng Zhang
- Biomedical Engineering and Physical Science Shared Resource, NIBIB, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Stanislav I. Tomarev
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Yihong Ye
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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145
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Kortvely E, Hauck SM, Behler J, Ho N, Ueffing M. The unconventional secretion of ARMS2. Hum Mol Genet 2016; 25:3143-3151. [DOI: 10.1093/hmg/ddw162] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 11/13/2022] Open
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146
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Curwin AJ, Brouwers N, Alonso Y Adell M, Teis D, Turacchio G, Parashuraman S, Ronchi P, Malhotra V. ESCRT-III drives the final stages of CUPS maturation for unconventional protein secretion. eLife 2016; 5. [PMID: 27115345 PMCID: PMC4868542 DOI: 10.7554/elife.16299] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 04/25/2016] [Indexed: 01/05/2023] Open
Abstract
The unconventional secretory pathway exports proteins that bypass the endoplasmic reticulum. In Saccharomyces cerevisiae, conditions that trigger Acb1 secretion via this pathway generate a Grh1 containing compartment composed of vesicles and tubules surrounded by a cup-shaped membrane and collectively called CUPS. Here we report a quantitative assay for Acb1 secretion that reveals requirements for ESCRT-I, -II, and -III but, surprisingly, without the involvement of the Vps4 AAA-ATPase. The major ESCRT-III subunit Snf7 localizes transiently to CUPS and this was accelerated in vps4Δ cells, correlating with increased Acb1 secretion. Microscopic analysis suggests that, instead of forming intraluminal vesicles with the help of Vps4, ESCRT-III/Snf7 promotes direct engulfment of preexisting Grh1 containing vesicles and tubules into a saccule to generate a mature Acb1 containing compartment. This novel multivesicular / multilamellar compartment, we suggest represents the stable secretory form of CUPS that is competent for the release of Acb1 to cells exterior. DOI:http://dx.doi.org/10.7554/eLife.16299.001 Cells produce thousands of different proteins with a variety of different roles in the body. Some proteins, for example the hormone insulin, perform roles outside of the cell and are released from cells in a process that has several stages. In the first step, newly-made insulin and many other “secretory” proteins enter a compartment called the endoplasmic reticulum. Once inside, these proteins can then be loaded into other compartments and transported to the edge of the cell. There is another class of secretory proteins that are released from the cell without first entering the endoplasmic reticulum, in a process termed “unconventional protein secretion”. A protein called Acb1 is released from yeast cells in this manner. Previous research identified a compartment that might be involved in this process. However, it is not clear how this compartment (named CUPS) forms, and what role it plays in unconventional protein secretion. Curwin et al. investigated how CUPS form in yeast cells, and whether the compartment contains Acb1 proteins. The experiments reveal that after CUPS form they need to mature into a form that is involved in the release of Acb1 proteins from the cell. This maturation process involves some, but not all, of the same genes as those involved in producing another type of compartment in cells called a multivesicular body. Acb1 is only found in the mature CUPS and multivesicular bodies are not involved in the release of this protein from the cell. Curwin et al.’s findings shed some light on how Acb1 and other secretory proteins can be released from cells without involving the endoplasmic reticulum. Future challenges are to reveal how CUPS capture cargo and find out how Acb1 leaves the CUPS to exit the cell. DOI:http://dx.doi.org/10.7554/eLife.16299.002
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Affiliation(s)
- Amy J Curwin
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Nathalie Brouwers
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Manuel Alonso Y Adell
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - David Teis
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Gabriele Turacchio
- Institute of Protein Biochemistry, National Research Council of Italy, Naples, Italy
| | | | - Paolo Ronchi
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Vivek Malhotra
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
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147
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Kirov A, Kacer D, Conley BA, Vary CPH, Prudovsky I. AHNAK2 Participates in the Stress-Induced Nonclassical FGF1 Secretion Pathway. J Cell Biochem 2016; 116:1522-31. [PMID: 25560297 DOI: 10.1002/jcb.25047] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 12/22/2022]
Abstract
FGF1 is a nonclassically released growth factor that regulates carcinogenesis, angiogenesis, and inflammation. In vitro and in vivo, FGF1 export is stimulated by cell stress. Upon stress, FGF1 is transported to the plasma membrane where it localizes prior to transmembrane translocation. To determine which proteins participate in the submembrane localization of FGF1 and its export, we used immunoprecipitation mass spectrometry to identify novel proteins that associate with FGF1 during heat shock. The heat shock-dependent association of FGF1 with the large protein AHNAK2 was observed. Heat shock induced the translocation of FGF1 and AHNAK2 to the cytoskeletal fraction. In heat-shocked cells, FGF1 and the C-terminal fragment of AHNAK2 colocalized with F-actin in the vicinity of the cell membrane. Depletion of AHNAK2 resulted in a drastic decrease of stress-induced FGF1 export but did not affect spontaneous FGF2 export and FGF1 release induced by the inhibition of Notch signaling. Thus, AHNAK2 is an important element of the FGF1 nonclassical export pathway.
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Affiliation(s)
- Aleksandr Kirov
- Center for Molecular Medicine, Maine Medical Center Research Institute, Maine Medical Center, Scarborough, 04074, Maine
| | - Doreen Kacer
- Center for Molecular Medicine, Maine Medical Center Research Institute, Maine Medical Center, Scarborough, 04074, Maine
| | - Barbara A Conley
- Center for Molecular Medicine, Maine Medical Center Research Institute, Maine Medical Center, Scarborough, 04074, Maine
| | - Calvin P H Vary
- Center for Molecular Medicine, Maine Medical Center Research Institute, Maine Medical Center, Scarborough, 04074, Maine
| | - Igor Prudovsky
- Center for Molecular Medicine, Maine Medical Center Research Institute, Maine Medical Center, Scarborough, 04074, Maine
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148
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Abstract
Autophagy is a lysosomal degradation process crucial for adaptation to stress and cellular homeostasis. In cancer, autophagy has been demonstrated to serve multifaceted roles in tumor initiation and progression. Although genetic evidence corroborates a role for autophagy as a tumor suppressor mechanism during tumor initiation, autophagy also sustains metabolic pathways in cancer cells and promotes survival within the harsh tumor microenvironment and in response to diverse anticancer therapies. Moreover, though traditionally viewed as an autodigestive process, more recent work demonstrates that autophagy also facilitates cellular secretion; the importance of these new functions of the autophagy pathway is being increasingly appreciated during cancer progression and treatment. In this review, we discuss how these evolving and diverse roles for autophagy both impede and promote tumorigenesis.
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Affiliation(s)
- J Liu
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, United States
| | - J Debnath
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, United States.
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149
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Taverna E, Mora-Bermúdez F, Strzyz PJ, Florio M, Icha J, Haffner C, Norden C, Wilsch-Bräuninger M, Huttner WB. Non-canonical features of the Golgi apparatus in bipolar epithelial neural stem cells. Sci Rep 2016; 6:21206. [PMID: 26879757 PMCID: PMC4754753 DOI: 10.1038/srep21206] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/19/2016] [Indexed: 12/13/2022] Open
Abstract
Apical radial glia (aRG), the stem cells in developing neocortex, are unique bipolar epithelial cells, extending an apical process to the ventricle and a basal process to the basal lamina. Here, we report novel features of the Golgi apparatus, a central organelle for cell polarity, in mouse aRGs. The Golgi was confined to the apical process but not associated with apical centrosome(s). In contrast, in aRG-derived, delaminating basal progenitors that lose apical polarity, the Golgi became pericentrosomal. The aRG Golgi underwent evolutionarily conserved, accordion-like compression and extension concomitant with cell cycle-dependent nuclear migration. Importantly, in line with endoplasmic reticulum but not Golgi being present in the aRG basal process, its plasma membrane contained glycans lacking Golgi processing, consistent with direct ER-to-cell surface membrane traffic. Our study reveals hitherto unknown complexity of neural stem cell polarity, differential Golgi contribution to their specific architecture, and fundamental Golgi re-organization upon cell fate change.
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Affiliation(s)
- Elena Taverna
- Max-Planck Inst. of Mol. Cell Biol. and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
| | - Felipe Mora-Bermúdez
- Max-Planck Inst. of Mol. Cell Biol. and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
| | - Paulina J Strzyz
- Max-Planck Inst. of Mol. Cell Biol. and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
| | - Marta Florio
- Max-Planck Inst. of Mol. Cell Biol. and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
| | - Jaroslav Icha
- Max-Planck Inst. of Mol. Cell Biol. and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
| | - Christiane Haffner
- Max-Planck Inst. of Mol. Cell Biol. and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
| | - Caren Norden
- Max-Planck Inst. of Mol. Cell Biol. and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
| | | | - Wieland B Huttner
- Max-Planck Inst. of Mol. Cell Biol. and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
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150
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Abstract
Originally identified as Golgi stacking factors in vitro, the Golgi reassembly stacking protein (GRASP) family has been shown to act as membrane tethers with multiple cellular roles. As an update to previous comprehensive reviews of the GRASP family (Giuliani et al., 2011; Vinke et al., 2011; Jarvela and Linstedt, 2012), we outline here the latest findings concerning their diverse roles. New insights into the mechanics of GRASP-mediated tethering come from recent crystal structures. The models of how GRASP65 and GRASP55 tether membranes relate directly to their role in Golgi ribbon formation in mammalian cells and the unlinking of the ribbon at the onset of mitosis. However, it is also clear that GRASPs act outside the Golgi with roles at the ER and ER exit sites (ERES). Furthermore, the proteins of this family display other roles upon cellular stress, especially in mediating unconventional secretion of both transmembrane proteins (Golgi bypass) and cytoplasmic proteins (through secretory autophagosomes).
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Affiliation(s)
- Catherine Rabouille
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC UtrechtUtrecht, Netherlands; The Department of Cell Biology, University Medical Center UtrechtUtrecht, Netherlands
| | - Adam D Linstedt
- Department of Biological Sciences, Carnegie Mellon University Pittsburgh, PA, USA
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