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Brockmöller S, Worek F, Rothmiller S. Protein networking: nicotinic acetylcholine receptors and their protein-protein-associations. Mol Cell Biochem 2024; 479:1627-1642. [PMID: 38771378 DOI: 10.1007/s11010-024-05032-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 05/04/2024] [Indexed: 05/22/2024]
Abstract
Nicotinic acetylcholine receptors (nAChR) are complex transmembrane proteins involved in neurotransmission in the nervous system and at the neuromuscular junction. nAChR disorders may lead to severe, potentially fatal pathophysiological states. To date, the receptor has been the focus of basic and applied research to provide novel therapeutic interventions. Since most studies have investigated only the nAChR itself, it is necessary to consider the receptor as part of its protein network to understand or elucidate-specific pathways. On its way through the secretory pathway, the receptor interacts with several chaperones and proteins. This review takes a closer look at these molecular interactions and focuses especially on endoplasmic reticulum biogenesis, secretory pathway sorting, Golgi maturation, plasma membrane presentation, retrograde internalization, and recycling. Additional knowledge regarding the nAChR protein network may lead to a more detailed comprehension of the fundamental pathomechanisms of diseases or may lead to the discovery of novel therapeutic drug targets.
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Affiliation(s)
- Sabrina Brockmöller
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Bavaria, Germany.
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Bavaria, Germany
| | - Simone Rothmiller
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Bavaria, Germany
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2
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Galli A, Arunagiri A, Dule N, Castagna M, Marciani P, Perego C. Cholesterol Redistribution in Pancreatic β-Cells: A Flexible Path to Regulate Insulin Secretion. Biomolecules 2023; 13:224. [PMID: 36830593 PMCID: PMC9953638 DOI: 10.3390/biom13020224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/17/2023] [Accepted: 01/21/2023] [Indexed: 01/26/2023] Open
Abstract
Pancreatic β-cells, by secreting insulin, play a key role in the control of glucose homeostasis, and their dysfunction is the basis of diabetes development. The metabolic milieu created by high blood glucose and lipids is known to play a role in this process. In the last decades, cholesterol has attracted significant attention, not only because it critically controls β-cell function but also because it is the target of lipid-lowering therapies proposed for preventing the cardiovascular complications in diabetes. Despite the remarkable progress, understanding the molecular mechanisms responsible for cholesterol-mediated β-cell function remains an open and attractive area of investigation. Studies indicate that β-cells not only regulate the total cholesterol level but also its redistribution within organelles, a process mediated by vesicular and non-vesicular transport. The aim of this review is to summarize the most current view of how cholesterol homeostasis is maintained in pancreatic β-cells and to provide new insights on the mechanisms by which cholesterol is dynamically distributed among organelles to preserve their functionality. While cholesterol may affect virtually any activity of the β-cell, the intent of this review is to focus on early steps of insulin synthesis and secretion, an area still largely unexplored.
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Affiliation(s)
- Alessandra Galli
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), Università degli Studi di Milano, 20134 Milan, Italy
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MA 48106, USA
| | - Nevia Dule
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), Università degli Studi di Milano, 20134 Milan, Italy
| | - Michela Castagna
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), Università degli Studi di Milano, 20134 Milan, Italy
| | - Paola Marciani
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), Università degli Studi di Milano, 20134 Milan, Italy
| | - Carla Perego
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), Università degli Studi di Milano, 20134 Milan, Italy
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3
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Retro-2 alters Golgi structure. Sci Rep 2022; 12:14975. [PMID: 36056100 PMCID: PMC9438350 DOI: 10.1038/s41598-022-19415-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 08/29/2022] [Indexed: 11/28/2022] Open
Abstract
Retro-2 directly interacts with an ER exit site protein, Sec16A, inhibiting ER exit of a Golgi tSNARE, Syntaxin5, which results in rapid re-distribution of Syntaxin5 to the ER. Recently, it was shown that SARS-CoV-2 infection disrupts the Golgi apparatus within 6–12 h, while its replication was effectively inhibited by Retro-2 in cultured human lung cells. Yet, exactly how Retro-2 may influence ultrastructure of the Golgi apparatus have not been thoroughly investigated. In this study, we characterized the effect of Retro-2 treatment on ultrastructure of the Golgi apparatus using electron microscopy and EM tomography. Our initial results on protein secretion showed that Retro-2 treatment does not significantly influence secretion of either small or large cargos. Ultra-structural study of the Golgi, however, revealed rapid accumulation of COPI-like vesicular profiles in the perinuclear area and a partial disassembly of the Golgi stack under electron microscope within 3–5 h, suggesting altered Golgi organization in these cells. Retro-2 treatment in cells depleted of GRASP65/55, the two well-known Golgi structural proteins, induced complete and rapid disassembly of the Golgi into individual cisterna. Taken together, these results suggest that Retro-2 profoundly alters Golgi structure to a much greater extent than previously anticipated.
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Yang F, Gao Y, Liu J, Chen Z, de Dios VR, Gao Q, Zhang M, Peng Z, Yao Y. Metal tolerance protein MTP6 is involved in Mn and Co distribution in poplar. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 226:112868. [PMID: 34619477 DOI: 10.1016/j.ecoenv.2021.112868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/27/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
With the booming demand of the electric vehicle industry, the concentration of manganese (Mn) and cobalt (Co) flowing into land ecosystems has also increased significantly. While these transition metals can promote the growth and development of plants, they may become toxic under high concentrations. It is thus important to understand how Mn and Co are distributed in plants to develop novel germplasms for the remediation of these heavy metals in contaminated soils. Here, an MTP gene that encodes the CDF (cation diffusion facilitator) protein in Populus trichocarpa, PtrMTP6, was screened as the key gene involved in the distribution of both Mn and Co in poplar. The PtrMTP6-GFP fusion protein was co-localized with the mRFP-VSR2, showing that PtrMTP6 proteins are present at the pre-vacuolar compartment (PVC). Yeast mutant complementation assays further identified that PtrMTP6 serves as a Mn and Co transporter, reducing yeast cell toxicity after exposure to excessive Mn or Co. Histochemical analyses showed that PtrMTP6 was mainly expressed in phloem, suggesting that PtrMTP6 probably involved in the Mn and Co transport via phloem in plants. Under excess Co, PtrMTP6 overexpressing poplar lines were more severely damaged than the control due to higher Co accumulations in young tissue. PtrMTP6 overexpressing lines showed little change in their tolerance to excess Mn, although young tissues also accumulated more Mn. PtrMTP6 play important roles in Mn and Co distribution in poplar and further research on its regulation will be important to increase bioremediation in Mn and Co polluted ecosystems.
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Affiliation(s)
- Fengming Yang
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China
| | - Yongfeng Gao
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
| | - Jikai Liu
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China
| | - Zihao Chen
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China
| | - Víctor Resco de Dios
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China; Department of Crop and Forest Sciences & Joint Research Unit CTFC-AGROTECNIO-CERCA Center, Universitat de Lleida, 25198 Lleida, Spain
| | - Qian Gao
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China
| | - Meng Zhang
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China
| | - Zhuoxi Peng
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China
| | - Yinan Yao
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
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Wiktor M, Wiertelak W, Maszczak-Seneczko D, Balwierz PJ, Szulc B, Olczak M. Identification of novel potential interaction partners of UDP-galactose (SLC35A2), UDP-N-acetylglucosamine (SLC35A3) and an orphan (SLC35A4) nucleotide sugar transporters. J Proteomics 2021; 249:104321. [PMID: 34242836 DOI: 10.1016/j.jprot.2021.104321] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 10/20/2022]
Abstract
Nucleotide sugar transporters (NSTs) are ER and Golgi-resident members of the solute carrier 35 (SLC35) family which supply substrates for glycosylation by exchanging lumenal nucleotide monophosphates for cytosolic nucleotide sugars. Defective NSTs have been associated with congenital disorders of glycosylation (CDG), however, molecular basis of many types of CDG remains poorly characterized. To better understand the biology of NSTs, we identified potential interaction partners of UDP-galactose transporter (SLC35A2), UDP-N-acetylglucosamine transporter (SLC35A3) and an orphan nucleotide sugar transporter SLC35A4 of to date unassigned specificity. For this purpose, each of the SLC35A2-A4 proteins was used as a bait in four independent pull-down experiments and the identity of the immunoprecipitated material was discovered using MS techniques. From the candidate list obtained, we selected a few for which the interaction was confirmed in vitro using the NanoBiT system, a split luciferase-based luminescent technique. NSTs have been shown to interact with two ATPases (ATP2A2, ATP2C1), Golgi pH regulator B (GPR89B) and calcium channel (TMCO1), which may reflect the regulation of glycosylation by ion homeostasis, and with basigin (BSG). Our findings provide a starting point for the NST interaction network discovery in order to better understand how glycosylation is regulated and linked to other cellular processes. SIGNIFICANCE: Despite the facts that nucleotide sugar transporters are a key component of the protein glycosylation machinery, and deficiencies in their activity underlie serious metabolic diseases, biology, function and regulation of these essential proteins remain enigmatic. In this study we have advanced the field by identifying sets of new potential interaction partners for UDP-galactose transporter (SLC35A2), UDP-N-acetylglucosamine transporter (SLC35A3) and an orphan transporter SLC35A4 of yet undefined role. Several of these new interactions were additionally confirmed in vitro using the NanoBiT system, a split luciferase complementation assay. This work is also significant in that it addresses the overall challenge of discovering membrane protein interaction partners by a detailed comparison of 4 different co-immunoprecipitation strategies and by custom sample preparation and data processing workflows.
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Affiliation(s)
- Maciej Wiktor
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland.
| | - Wojciech Wiertelak
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland.
| | | | - Piotr Jan Balwierz
- Computational Regulatory Genomics, MRC-London Institute of Medical Sciences, London, United Kingdom.
| | - Bożena Szulc
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland.
| | - Mariusz Olczak
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland.
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6
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Tiwari N, Graham M, Liu X, Yue X, Zhu L, Meshram D, Choi S, Qian Y, Rothman JE, Lee I. Golgin45-Syntaxin5 Interaction Contributes to Structural Integrity of the Golgi Stack. Sci Rep 2019; 9:12465. [PMID: 31462665 PMCID: PMC6713708 DOI: 10.1038/s41598-019-48875-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 08/14/2019] [Indexed: 12/15/2022] Open
Abstract
The unique stacked morphology of the Golgi apparatus had been a topic of intense investigation among the cell biologists over the years. We had previously shown that the two Golgin tethers (GM130 and Golgin45) could, to a large degree, functionally substitute for GRASP-type Golgi stacking proteins to sustain normal Golgi morphology and function in GRASP65/55-double depleted HeLa cells. However, compared to well-studied GM130, the exact role of Golgin45 in Golgi structure remains poorly understood. In this study, we aimed to further characterize the functional role of Golgin45 in Golgi structure and identified Golgin45 as a novel Syntaxin5-binding protein. Based primarily on a sequence homology between Golgin45 and GM130, we found that a leucine zipper-like motif in the central coiled-coil region of Golgin45 appears to serve as a Syntaxin5 binding domain. Mutagenesis study of this conserved domain in Golgin45 showed that a point mutation (D171A) can abrogate the interaction between Golgin45 and Syntaxin5 in pull-down assays using recombinant proteins, whereas this mutant Golgin45 binding to Rab2-GTP was unaffected in vitro. Strikingly, exogenous expression of this Syntaxin5 binding deficient mutant (D171A) of Golgin45 in HeLa cells resulted in frequent intercisternal fusion among neighboring Golgi cisterna, as readily observed by EM and EM tomography. Further, double depletion of the two Syntaxin5-binding Golgin tethers also led to significant intercisternal fusion, while double depletion of GRASP65/55 didn’t lead to this phenotype. These results suggest that certain tether-SNARE interaction within Golgi stack may play a role in inhibiting intercisternal fusion among neighboring cisternae, thereby contributing to structural integrity of the Golgi stack.
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Affiliation(s)
- Neeraj Tiwari
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Morven Graham
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Xinran Liu
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Xihua Yue
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Lianhui Zhu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Dipak Meshram
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Sunkyu Choi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yi Qian
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - James E Rothman
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Intaek Lee
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
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Yue X, Qian Y, Gim B, Lee I. Acyl-CoA-Binding Domain-Containing 3 (ACBD3; PAP7; GCP60): A Multi-Functional Membrane Domain Organizer. Int J Mol Sci 2019; 20:ijms20082028. [PMID: 31022988 PMCID: PMC6514682 DOI: 10.3390/ijms20082028] [Citation(s) in RCA: 20] [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: 03/15/2019] [Revised: 04/13/2019] [Accepted: 04/15/2019] [Indexed: 01/04/2023] Open
Abstract
Acyl-CoA-binding domain-containing 3 (ACBD3) is a multi-functional scaffolding protein, which has been associated with a diverse array of cellular functions, including steroidogenesis, embryogenesis, neurogenesis, Huntington’s disease (HD), membrane trafficking, and viral/bacterial proliferation in infected host cells. In this review, we aim to give a timely overview of recent findings on this protein, including its emerging role in membrane domain organization at the Golgi and the mitochondria. We hope that this review provides readers with useful insights on how ACBD3 may contribute to membrane domain organization along the secretory pathway and on the cytoplasmic surface of intracellular organelles, which influence many important physiological and pathophysiological processes in mammalian cells.
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Affiliation(s)
- Xihua Yue
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai 201210, China.
| | - Yi Qian
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai 201210, China.
| | - Bopil Gim
- School of Physical Science and Technology, ShanghaiTech University, Pudong, Shanghai 201210, China.
| | - Intaek Lee
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai 201210, China.
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8
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Pakdel M, von Blume J. Exploring new routes for secretory protein export from the trans-Golgi network. Mol Biol Cell 2019; 29:235-240. [PMID: 29382805 PMCID: PMC5996961 DOI: 10.1091/mbc.e17-02-0117] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/30/2017] [Accepted: 12/01/2017] [Indexed: 12/21/2022] Open
Abstract
Sorting of soluble proteins for transport to intracellular compartments and for secretion from cells is essential for cell and tissue homeostasis. The trans-Golgi network (TGN) is a major sorting station that sorts secretory proteins into specific carriers to transport them to their final destinations. The sorting of lysosomal hydrolases at the TGN by the mannose 6-phosphate receptor is well understood. The recent discovery of a Ca2+-based sorting of secretory cargo at the TGN is beginning to uncover the mechanism by which cells sort secretory cargoes from Golgi residents and cargoes destined to the other cellular compartments. This Ca2+-based sorting involves the cytoplasmic actin cytoskeleton, which through membrane anchored Ca2+ ATPase SPCA1 and the luminal Ca2+ binding protein Cab45 sorts of a subset of secretory proteins at the TGN. We present this discovery and highlight important challenges that remain unaddressed in the overall pathway of cargo sorting at the TGN.
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Affiliation(s)
- Mehrshad Pakdel
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Julia von Blume
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
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Martín M, Modenutti CP, Peyret V, Geysels RC, Darrouzet E, Pourcher T, Masini-Repiso AM, Martí MA, Carrasco N, Nicola JP. A Carboxy-Terminal Monoleucine-Based Motif Participates in the Basolateral Targeting of the Na+/I- Symporter. Endocrinology 2019; 160:156-168. [PMID: 30496374 PMCID: PMC6936561 DOI: 10.1210/en.2018-00603] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 11/20/2018] [Indexed: 12/26/2022]
Abstract
The Na+/iodide (I-) symporter (NIS), a glycoprotein expressed at the basolateral plasma membrane of thyroid follicular cells, mediates I- accumulation for thyroid hormonogenesis and radioiodide therapy for differentiated thyroid carcinoma. However, differentiated thyroid tumors often exhibit lower I- transport than normal thyroid tissue (or even undetectable I- transport). Paradoxically, the majority of differentiated thyroid cancers show intracellular NIS expression, suggesting abnormal targeting to the plasma membrane. Therefore, a thorough understanding of the mechanisms that regulate NIS plasma membrane transport would have multiple implications for radioiodide therapy. In this study, we show that the intracellularly facing carboxy-terminus of NIS is required for the transport of the protein to the plasma membrane. Moreover, the carboxy-terminus contains dominant basolateral information. Using internal deletions and site-directed mutagenesis at the carboxy-terminus, we identified a highly conserved monoleucine-based sorting motif that determines NIS basolateral expression. Furthermore, in clathrin adaptor protein (AP)-1B-deficient cells, NIS sorting to the basolateral plasma membrane is compromised, causing the protein to also be expressed at the apical plasma membrane. Computer simulations suggest that the AP-1B subunit σ1 recognizes the monoleucine-based sorting motif in NIS carboxy-terminus. Although the mechanisms by which NIS is intracellularly retained in thyroid cancer remain elusive, our findings may open up avenues for identifying molecular targets that can be used to treat radioiodide-refractory thyroid tumors that express NIS intracellularly.
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Affiliation(s)
- Mariano Martín
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología–Consejo Nacional de Investigaciones Científicas y Técnicas (CIBICI–CONICET), Córdoba, Argentina
| | - Carlos Pablo Modenutti
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales–Consejo Nacional de Investigaciones Científicas y Técnicas (IQUIBICEN–CONICET), Buenos Aires, Argentina
- Correspondence: Juan Pablo Nicola, PhD, Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Centro de Investigaciones en Bioquímica Clínica e Inmunología–Consejo Nacional de Investigaciones Científicas y Técnicas (CIBICI–CONICET), Haya de la Torre y Medina Allende, Córdoba X5000HUA, Argentina. E-mail:
| | - Victoria Peyret
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología–Consejo Nacional de Investigaciones Científicas y Técnicas (CIBICI–CONICET), Córdoba, Argentina
| | - Romina Celeste Geysels
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología–Consejo Nacional de Investigaciones Científicas y Técnicas (CIBICI–CONICET), Córdoba, Argentina
| | - Elisabeth Darrouzet
- Laboratoire Transporteurs en Imagerie et Radiothérapie en Oncologie, Faculté de Médecine, Université de Nice Sophia Antipolis–Université Côte d’Azur, Nice, France
- Laboratoire Transporteurs en Imagerie et Radiothérapie en Oncologie, Faculté de Médecine, Commissariat à l’Energie Atomique, Nice, France
| | - Thierry Pourcher
- Laboratoire Transporteurs en Imagerie et Radiothérapie en Oncologie, Faculté de Médecine, Université de Nice Sophia Antipolis–Université Côte d’Azur, Nice, France
- Laboratoire Transporteurs en Imagerie et Radiothérapie en Oncologie, Faculté de Médecine, Commissariat à l’Energie Atomique, Nice, France
| | - Ana María Masini-Repiso
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología–Consejo Nacional de Investigaciones Científicas y Técnicas (CIBICI–CONICET), Córdoba, Argentina
| | - Marcelo Adrián Martí
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales–Consejo Nacional de Investigaciones Científicas y Técnicas (IQUIBICEN–CONICET), Buenos Aires, Argentina
| | - Nancy Carrasco
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
| | - Juan Pablo Nicola
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología–Consejo Nacional de Investigaciones Científicas y Técnicas (CIBICI–CONICET), Córdoba, Argentina
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10
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Wang X, Hybiske K, Stephens RS. Orchestration of the mammalian host cell glucose transporter proteins-1 and 3 by Chlamydia contributes to intracellular growth and infectivity. Pathog Dis 2018; 75:4411801. [PMID: 29040458 DOI: 10.1093/femspd/ftx108] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 10/05/2017] [Indexed: 01/03/2023] Open
Abstract
Chlamydia are gram-negative obligate intracellular bacteria that replicate within a discrete cellular vacuole, called an inclusion. Although it is known that Chlamydia require essential nutrients from host cells to support their intracellular growth, the molecular mechanisms for acquiring these macromolecules remain uncharacterized. In the present study, it was found that the expression of mammalian cell glucose transporter proteins 1 (GLUT1) and glucose transporter proteins 3 (GLUT3) were up-regulated during chlamydial infection. Up-regulation was dependent on bacterial protein synthesis and Chlamydia-induced MAPK kinase activation. GLUT1, but not GLUT3, was observed in close proximity to the inclusion membrane throughout the chlamydial developmental cycle. The proximity of GLUT1 to the inclusion was dependent on a brefeldin A-sensitive pathway. Knockdown of GLUT1 and GLUT3 with specific siRNA significantly impaired chlamydial development and infectivity. It was discovered that the GLUT1 protein was stabilized during infection by inhibition of host-dependent ubiquitination of GLUT1, and this effect was associated with the chlamydial deubiquitinase effector protein CT868. This report demonstrates that Chlamydia exploits host-derived transporter proteins altering their expression, turnover and localization. Consequently, host cell transporter proteins are manipulated during infection as a transport system to fulfill the carbon source requirements for Chlamydia.
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Affiliation(s)
- Xiaogang Wang
- Program in Infectious Diseases, School of Public Health, University of California, Berkeley, 51 Koshland Hall, CA 94720, USA.,Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Ave, Boston, MA 02115, USA
| | - Kevin Hybiske
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, 750 Republican St, Seattle, WA 98109, USA
| | - Richard S Stephens
- Program in Infectious Diseases, School of Public Health, University of California, Berkeley, 51 Koshland Hall, CA 94720, USA
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11
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Bakhaus K, Fietz D, Kliesch S, Weidner W, Bergmann M, Geyer J. The polymorphism L204F affects transport and membrane expression of the sodium-dependent organic anion transporter SOAT (SLC10A6). J Steroid Biochem Mol Biol 2018; 179:36-44. [PMID: 28951225 DOI: 10.1016/j.jsbmb.2017.09.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 08/29/2017] [Accepted: 09/21/2017] [Indexed: 01/05/2023]
Abstract
Sodium-dependent organic anion transporter (SOAT) represents a membrane transporter specific for sulfated steroid hormones, which are supposed to participate in the regulation of reproductive processes. In man, SOAT shows predominant mRNA expression in the testis and here was localized to primary spermatocytes. SOAT mRNA expression is significantly downregulated in different disorders of spermatogenesis, including hypospermatogenesis. The resulting decline of SOAT-mediated transport of sulfated steroids may participate in the impairment of functional spermatogenesis. Apart from downregulation of SOAT mRNA expression, genetic polymorphisms affecting the transport function of SOAT may have the same negative effect on spermatogenesis. Therefore, in the present study we searched for functionally relevant SOAT polymorphisms, aiming to comparatively analyze their occurrence in patients with impaired spermatogenesis vs. patients with intact spermatogenesis. We found that the SOAT polymorphism L204F showed a significantly reduced transport function for DHEAS when expressed in HEK293 cells. Although the Km value was identical with that of the SOAT wildtype, the Vmax value dramatically declined for the SOAT-L204F variant (942.5 vs. 313.6pmol×mg protein-1×min-1). Although the same amount of total SOAT-L204F protein was detected in transfected HEK293 cells compared to the SOAT wildtype, plasma membrane expression was significantly reduced, which points to a plasma membrane sorting defect of the SOAT-L204F variant. Groups of 20 subjects with normal spermatogenesis and 26 subjects with hypospermatogenesis were genotyped for this polymorphism. Both groups showed nearly identical distributions of the SOAT-L204F polymorphism (∼10% heterozygous and ∼5% homozygous), indicating that this polymorphism seems not be causative for hypospermatogenesis.
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Affiliation(s)
- Katharina Bakhaus
- Institute of Pharmacology and Toxicology, Justus Liebig University Giessen, Germany
| | - Daniela Fietz
- Department of Veterinary Anatomy, Histology and Embryology, Justus Liebig University Giessen, Germany
| | - Sabine Kliesch
- Department of Clinical Andrology, Centre for Reproductive Medicine and Andrology, University Hospital Münster, Germany
| | - Wolfgang Weidner
- Clinic for Urology, Pediatric Urology and Andrology, Justus Liebig University Giessen, Germany
| | - Martin Bergmann
- Department of Veterinary Anatomy, Histology and Embryology, Justus Liebig University Giessen, Germany
| | - Joachim Geyer
- Institute of Pharmacology and Toxicology, Justus Liebig University Giessen, Germany.
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Alam K, Crowe A, Wang X, Zhang P, Ding K, Li L, Yue W. Regulation of Organic Anion Transporting Polypeptides (OATP) 1B1- and OATP1B3-Mediated Transport: An Updated Review in the Context of OATP-Mediated Drug-Drug Interactions. Int J Mol Sci 2018. [PMID: 29538325 PMCID: PMC5877716 DOI: 10.3390/ijms19030855] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Organic anion transporting polypeptides (OATP) 1B1 and OATP1B3 are important hepatic transporters that mediate the uptake of many clinically important drugs, including statins from the blood into the liver. Reduced transport function of OATP1B1 and OATP1B3 can lead to clinically relevant drug-drug interactions (DDIs). Considering the importance of OATP1B1 and OATP1B3 in hepatic drug disposition, substantial efforts have been given on evaluating OATP1B1/1B3-mediated DDIs in order to avoid unwanted adverse effects of drugs that are OATP substrates due to their altered pharmacokinetics. Growing evidences suggest that the transport function of OATP1B1 and OATP1B3 can be regulated at various levels such as genetic variation, transcriptional and post-translational regulation. The present review summarizes the up to date information on the regulation of OATP1B1 and OATP1B3 transport function at different levels with a focus on potential impact on OATP-mediated DDIs.
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Affiliation(s)
- Khondoker Alam
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA.
| | - Alexandra Crowe
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA.
| | - Xueying Wang
- Center for Computational Biology and Bioinformatics, Indiana Institute of Personalized Medicine, Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
| | - Pengyue Zhang
- Center for Computational Biology and Bioinformatics, Indiana Institute of Personalized Medicine, Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
| | - Kai Ding
- Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73126, USA.
| | - Lang Li
- Center for Computational Biology and Bioinformatics, Indiana Institute of Personalized Medicine, Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
- Department of Biomedical Informatics, Ohio State University, Columbus, OH 43210, USA.
| | - Wei Yue
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA.
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Otero MG, Bessone IF, Hallberg AE, Cromberg LE, De Rossi MC, Saez TM, Levi V, Almenar-Queralt A, Falzone TL. Proteasome stress leads to APP axonal transport defects by promoting its amyloidogenic processing in lysosomes. J Cell Sci 2018; 131:jcs.214536. [DOI: 10.1242/jcs.214536] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 04/25/2018] [Indexed: 01/25/2023] Open
Abstract
Alzheimer Disease (AD) pathology includes the accumulation of poly-ubiquitinated proteins and failures in proteasome-dependent degradation. Whereas the distribution of proteasomes and its role in synaptic function have been studied, whether proteasome activity regulates the axonal transport and metabolism of the amyloid precursor protein (APP), remains elusive. Using live imaging in primary hippocampal neurons, we showed that proteasome inhibition rapidly and severely impairs the axonal transport of APP. Fluorescent cross-correlation analyses and membrane internalization blockage showed that plasma membrane APP do not contribute to transport defects. Moreover, by western blots and double-color APP imaging we demonstrated that proteasome inhibition precludes APP axonal transport by enhancing its endo-lysosomal delivery where β-cleavage is induced. Together, we found that proteasomes controls the distal transport of APP and can re-distribute Golgi-derived vesicles to the endo-lysosomal pathway. This crosstalk between proteasomes and lysosomes regulates APP intracellular dynamics, and defects in proteasome activity can be considered a contributing factor that lead to abnormal APP metabolism in AD.
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Affiliation(s)
- María Gabriela Otero
- Instituto de Biología Celular y Neurociencias, IBCN (CONICET-UBA), Facultad de Medicina, Universidad de Buenos Aires. Paraguay 2155, Buenos Aires, CP1121, Argentina
| | - Ivan Fernandez Bessone
- Instituto de Biología Celular y Neurociencias, IBCN (CONICET-UBA), Facultad de Medicina, Universidad de Buenos Aires. Paraguay 2155, Buenos Aires, CP1121, Argentina
| | - Alan Earle Hallberg
- Instituto de Biología Celular y Neurociencias, IBCN (CONICET-UBA), Facultad de Medicina, Universidad de Buenos Aires. Paraguay 2155, Buenos Aires, CP1121, Argentina
| | - Lucas Eneas Cromberg
- Instituto de Biología Celular y Neurociencias, IBCN (CONICET-UBA), Facultad de Medicina, Universidad de Buenos Aires. Paraguay 2155, Buenos Aires, CP1121, Argentina
| | - María Cecilia De Rossi
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica-IQUIBICEN UBA-CONICET, CP1428EGA, Argentina
| | - Trinidad M. Saez
- Instituto de Biología Celular y Neurociencias, IBCN (CONICET-UBA), Facultad de Medicina, Universidad de Buenos Aires. Paraguay 2155, Buenos Aires, CP1121, Argentina
- Instituto de Biología y Medicina Experimental, IBYME (CONICET). Vuelta de obligado 2490, Buenos Aires, CP 1428, Argentina
| | - Valeria Levi
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica-IQUIBICEN UBA-CONICET, CP1428EGA, Argentina
| | - Angels Almenar-Queralt
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Tomás Luis Falzone
- Instituto de Biología Celular y Neurociencias, IBCN (CONICET-UBA), Facultad de Medicina, Universidad de Buenos Aires. Paraguay 2155, Buenos Aires, CP1121, Argentina
- Instituto de Biología y Medicina Experimental, IBYME (CONICET). Vuelta de obligado 2490, Buenos Aires, CP 1428, Argentina
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14
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Song L, Chen Y, Du Y, Wang X, Guo X, Dong J, Xiao D. Saccharomyces cerevisiae proteinase A excretion and wine making. World J Microbiol Biotechnol 2017; 33:210. [DOI: 10.1007/s11274-017-2361-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/26/2017] [Indexed: 01/20/2023]
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15
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Murray M, Zhou F. Trafficking and other regulatory mechanisms for organic anion transporting polypeptides and organic anion transporters that modulate cellular drug and xenobiotic influx and that are dysregulated in disease. Br J Pharmacol 2017; 174:1908-1924. [PMID: 28299773 DOI: 10.1111/bph.13785] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 03/01/2017] [Accepted: 03/05/2017] [Indexed: 12/25/2022] Open
Abstract
Organic anion transporters (OATs) and organic anion-transporting polypeptides (OATPs), encoded by a number of solute carrier (SLC)22A and SLC organic anion (SLCO) genes, mediate the absorption and distribution of drugs and other xenobiotics. The regulation of OATs and OATPs is complex, comprising both transcriptional and post-translational mechanisms. Plasma membrane expression is required for cellular substrate influx by OATs/OATPs. Thus, interest in post-translational regulatory processes, including membrane targeting, endocytosis, recycling and degradation of transporter proteins, is increasing because these are critical for plasma membrane expression. After being synthesized, transporters undergo N-glycosylation in the endoplasmic reticulum and Golgi apparatus and are delivered to the plasma membrane by vesicular transport. Their expression at the cell surface is maintained by de novo synthesis and recycling, which occurs after clathrin- and/or caveolin-dependent endocytosis of existing protein. Several studies have shown that phosphorylation by signalling kinases is important for the internalization and recycling processes, although the transporter protein does not appear to be directly phosphorylated. After internalization, transporters that are targeted for degradation undergo ubiquitination, most likely on intracellular loop residues. Epigenetic mechanisms, including methylation of gene regulatory regions and transcription from alternate promoters, are also significant in the regulation of certain SLC22A/SLCO genes. The membrane expression of OATs/OATPs is dysregulated in disease, which affects drug efficacy and detoxification. Several transporters are expressed in the cytoplasmic subcompartment in disease states, which suggests that membrane targeting/internalization/recycling may be impaired. This article focuses on recent developments in OAT and OATP regulation, their dysregulation in disease and the significance for drug therapy.
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Affiliation(s)
- Michael Murray
- Pharmacogenomics and Drug Development Group, Discipline of Pharmacology, School of Medical Sciences, The University of Sydney, NSW, 2006, Australia
| | - Fanfan Zhou
- Faculty of Pharmacy, The University of Sydney, NSW, 2006, Australia
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16
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Adaptor protein-3: A key player in RBL-2H3 mast cell mediator release. PLoS One 2017; 12:e0173462. [PMID: 28273137 PMCID: PMC5342237 DOI: 10.1371/journal.pone.0173462] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 02/22/2017] [Indexed: 11/30/2022] Open
Abstract
Mast cell (MC) secretory granules are Lysosome-Related Organelles (LROs) whose biogenesis is associated with the post-Golgi secretory and endocytic pathways in which the sorting of proteins destined for a specific organelle relies on the recognition of sorting signals by adaptor proteins that direct their incorporation into transport vesicles. The adaptor protein 3 (AP-3) complex mediates protein trafficking between the trans-Golgi network (TGN) and late endosomes, lysosomes, and LROs. AP-3 has a recognized role in LROs biogenesis and regulated secretion in several cell types, including many immune cells such as neutrophils, natural killer cells, and cytotoxic T lymphocytes. However, the relevance of AP-3 for these processes in MCs has not been previously investigated. AP-3 was found to be expressed and distributed in a punctate fashion in rat peritoneal mast cells ex vivo. The rat MC line RBL-2H3 was used as a model system to investigate the role of AP-3 in mast cell secretory granule biogenesis and mediator release. By immunofluorescence and immunoelectron microscopy, AP-3 was localized both to the TGN and early endosomes indicating that AP-3 dependent sorting of proteins to MC secretory granules originates in these organelles. ShRNA mediated depletion of the AP-3 δ subunit was shown to destabilize the AP-3 complex in RBL-2H3 MCs. AP-3 knockdown significantly affected MC regulated secretion of β-hexosaminidase without affecting total cellular enzyme levels. Morphometric evaluation of MC secretory granules by electron microscopy revealed that the area of MC secretory granules in AP-3 knockdown MCs was significantly increased, indicating that AP-3 is involved in MC secretory granule biogenesis. Furthermore, AP-3 knockdown had a selective impact on the secretion of newly formed and newly synthesized mediators. These results show for the first time that AP-3 plays a critical role in secretory granule biogenesis and mediator release in MCs.
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17
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Abstract
Simple and complex carbohydrates (glycans) have long been known to play major metabolic, structural and physical roles in biological systems. Targeted microbial binding to host glycans has also been studied for decades. But such biological roles can only explain some of the remarkable complexity and organismal diversity of glycans in nature. Reviewing the subject about two decades ago, one could find very few clear-cut instances of glycan-recognition-specific biological roles of glycans that were of intrinsic value to the organism expressing them. In striking contrast there is now a profusion of examples, such that this updated review cannot be comprehensive. Instead, a historical overview is presented, broad principles outlined and a few examples cited, representing diverse types of roles, mediated by various glycan classes, in different evolutionary lineages. What remains unchanged is the fact that while all theories regarding biological roles of glycans are supported by compelling evidence, exceptions to each can be found. In retrospect, this is not surprising. Complex and diverse glycans appear to be ubiquitous to all cells in nature, and essential to all life forms. Thus, >3 billion years of evolution consistently generated organisms that use these molecules for many key biological roles, even while sometimes coopting them for minor functions. In this respect, glycans are no different from other major macromolecular building blocks of life (nucleic acids, proteins and lipids), simply more rapidly evolving and complex. It is time for the diverse functional roles of glycans to be fully incorporated into the mainstream of biological sciences.
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Affiliation(s)
- Ajit Varki
- Departments of Medicine and Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California at San Diego, La Jolla, CA 92093-0687, USA
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18
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Fernandez-Fernandez MR, Ruiz-Garcia D, Martin-Solana E, Chichon FJ, Carrascosa JL, Fernandez JJ. 3D electron tomography of brain tissue unveils distinct Golgi structures that sequester cytoplasmic contents in neurons. J Cell Sci 2016; 130:83-89. [PMID: 27505890 DOI: 10.1242/jcs.188060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 07/27/2016] [Indexed: 12/12/2022] Open
Abstract
Macroautophagy is morphologically characterized by autophagosome formation. Autophagosomes are double-membraned vesicles that sequester cytoplasmic components for further degradation in the lysosome. Basal autophagy is paramount for intracellular quality control in post-mitotic cells but, surprisingly, the number of autophagosomes in post-mitotic neurons is very low, suggesting that alternative degradative structures could exist in neurons. To explore this possibility, we have examined neuronal subcellular architecture by performing three-dimensional (3D) electron tomography analysis of mouse brain tissue that had been preserved through high-pressure freezing. Here, we report that sequestration of neuronal cytoplasmic contents occurs at the Golgi complex in distinct and dynamic structures that coexist with autophagosomes in the brain. These structures are composed of several concentric double-membraned layers that appear to be formed simultaneously by the direct bending and sealing of discrete Golgi stacks. These structures are labelled for proteolytic enzymes, and lysosomes and late endosomes are found in contact with them, leading to the possibility that the sequestered material could be degraded inside them. Our findings highlight the key role that 3D electron tomography, together with tissue rapid-freezing techniques, will have in gaining new knowledge about subcellular architecture.
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Affiliation(s)
| | - Desire Ruiz-Garcia
- Macromolecular Structures Department, Centro Nacional de Biotecnología-CSIC, Darwin, 3, Cantoblanco, Madrid 28049, Spain
| | - Eva Martin-Solana
- Macromolecular Structures Department, Centro Nacional de Biotecnología-CSIC, Darwin, 3, Cantoblanco, Madrid 28049, Spain
| | - Francisco Javier Chichon
- Macromolecular Structures Department, Centro Nacional de Biotecnología-CSIC, Darwin, 3, Cantoblanco, Madrid 28049, Spain
| | - Jose L Carrascosa
- Macromolecular Structures Department, Centro Nacional de Biotecnología-CSIC, Darwin, 3, Cantoblanco, Madrid 28049, Spain
| | - Jose-Jesus Fernandez
- Macromolecular Structures Department, Centro Nacional de Biotecnología-CSIC, Darwin, 3, Cantoblanco, Madrid 28049, Spain
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19
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Li X, Ortega B, Kim B, Welling PA. A Common Signal Patch Drives AP-1 Protein-dependent Golgi Export of Inwardly Rectifying Potassium Channels. J Biol Chem 2016; 291:14963-72. [PMID: 27226616 PMCID: PMC4946915 DOI: 10.1074/jbc.m116.729822] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 05/12/2016] [Indexed: 12/30/2022] Open
Abstract
Nearly all members of the inwardly rectifying potassium (Kir) channel family share a cytoplasmic domain structure that serves as an unusual AP-1 clathrin adaptor-dependent Golgi export signal in one Kir channel, Kir2.1 (KCNJ2), raising the question whether Kir channels share a common Golgi export mechanism. Here we explore this idea, focusing on two structurally and functionally divergent Kir family members, Kir2.3 (KCNJ4) and Kir4.1/5.1 (KCNJ10/16), which have ∼50% amino identity. We found that Golgi export of both channels is blocked upon siRNA-mediated knockdown of the AP-1 γ subunit, as predicted for the common AP-1-dependent trafficking process. A comprehensive mutagenic analysis, guided by homology mapping in atomic resolution models of Kir2.1, Kir2.3, and Kir4.1/5.1, identified a common structure that serves as a recognition site for AP-1 binding and governs Golgi export. Larger than realized from previous studies with Kir2.1, the signal is created by a patch of residues distributed at the confluence of cytoplasmic N and C termini. The signal involves a stretch of hydrophobic residues from the C-terminal region that form a hydrophobic cleft, an adjacent cluster of basic residues within the N terminus, and a potential network of salt bridges that join the N- and C-terminal poles together. Because patch formation and AP-1 binding are dependent on proper folding of the cytoplasmic domains, the signal provides a common quality control mechanism at the Golgi for Kir channels. These findings identify a new proteostatic mechanism that couples protein folding of channels to forward trafficking in the secretory pathway.
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Affiliation(s)
- Xiangming Li
- From the Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland 21201 and
| | - Bernardo Ortega
- the Department of Biology, The College at Brockport, State University of New York, Brockport, New York 14420-2973
| | - Boyoung Kim
- From the Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland 21201 and
| | - Paul A Welling
- From the Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland 21201 and
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20
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Crevenna AH, Blank B, Maiser A, Emin D, Prescher J, Beck G, Kienzle C, Bartnik K, Habermann B, Pakdel M, Leonhardt H, Lamb DC, von Blume J. Secretory cargo sorting by Ca2+-dependent Cab45 oligomerization at the trans-Golgi network. J Cell Biol 2016; 213:305-14. [PMID: 27138253 PMCID: PMC4862333 DOI: 10.1083/jcb.201601089] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/06/2016] [Indexed: 11/22/2022] Open
Abstract
Crevenna et al. examine the mechanism by which secretory cargoes are segregated at the trans-Golgi network (TGN) for release into the extracellular space. The authors demonstrate that Ca2+-dependent changes in Cab45 oligomerization mediate sorting of specific cargo molecules at the TGN. Sorting and export of transmembrane cargoes and lysosomal hydrolases at the trans-Golgi network (TGN) are well understood. However, elucidation of the mechanism by which secretory cargoes are segregated for their release into the extracellular space remains a challenge. We have previously demonstrated that, in a reaction that requires Ca2+, the soluble TGN-resident protein Cab45 is necessary for the sorting of secretory cargoes at the TGN. Here, we report that Cab45 reversibly assembles into oligomers in the presence of Ca2+. These Cab45 oligomers specifically bind secretory proteins, such as COMP and LyzC, in a Ca2+-dependent manner in vitro. In intact cells, mutation of the Ca2+-binding sites in Cab45 impairs oligomerization, as well as COMP and LyzC sorting. Superresolution microscopy revealed that Cab45 colocalizes with secretory proteins and the TGN Ca2+ pump (SPCA1) in specific TGN microdomains. These findings reveal that Ca2+-dependent changes in Cab45 mediate sorting of specific cargo molecules at the TGN.
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Affiliation(s)
- Alvaro H. Crevenna
- Physical Chemistry, Department of Chemistry Center for Nanoscience, Nanosystems Initiative Munich and Center for Integrated Protein Science Munich, Ludwig Maximilians University Munich, 81377 Munich, Germany
| | - Birgit Blank
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Andreas Maiser
- Department of Biology II, Ludwig Maximilian University Munich, 82152 Martinsried, Germany
- Center for Integrated Protein Science, Ludwig Maximilians University Munich, 82152 Martinsried, Germany
| | - Derya Emin
- Physical Chemistry, Department of Chemistry Center for Nanoscience, Nanosystems Initiative Munich and Center for Integrated Protein Science Munich, Ludwig Maximilians University Munich, 81377 Munich, Germany
| | - Jens Prescher
- Physical Chemistry, Department of Chemistry Center for Nanoscience, Nanosystems Initiative Munich and Center for Integrated Protein Science Munich, Ludwig Maximilians University Munich, 81377 Munich, Germany
| | - Gisela Beck
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | | | - Kira Bartnik
- Physical Chemistry, Department of Chemistry Center for Nanoscience, Nanosystems Initiative Munich and Center for Integrated Protein Science Munich, Ludwig Maximilians University Munich, 81377 Munich, Germany
| | - Bianca Habermann
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Mehrshad Pakdel
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Heinrich Leonhardt
- Department of Biology II, Ludwig Maximilian University Munich, 82152 Martinsried, Germany
- Center for Integrated Protein Science, Ludwig Maximilians University Munich, 82152 Martinsried, Germany
| | - Don C. Lamb
- Physical Chemistry, Department of Chemistry Center for Nanoscience, Nanosystems Initiative Munich and Center for Integrated Protein Science Munich, Ludwig Maximilians University Munich, 81377 Munich, Germany
| | - Julia von Blume
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
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21
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Chen Y, Bharill S, Altun Z, O'Hagan R, Coblitz B, Isacoff EY, Chalfie M. Caenorhabditis elegans paraoxonase-like proteins control the functional expression of DEG/ENaC mechanosensory proteins. Mol Biol Cell 2016; 27:1272-85. [PMID: 26941331 PMCID: PMC4831881 DOI: 10.1091/mbc.e15-08-0561] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 02/23/2016] [Indexed: 12/22/2022] Open
Abstract
MEC-6 and POML-1 are similar proteins needed for touch sensitivity in Caenorhabditis elegans. These proteins reside primarily in the ER and affect the amount and localization of MEC-4, the DEG/ENaC mechanotransduction channel protein. MEC-6 also accelerates MEC-4 transport to the cell surface in vitro. Thus these proteins appear to act as MEC-4 chaperones. Caenorhabditis elegans senses gentle touch via a mechanotransduction channel formed from the DEG/ENaC proteins MEC-4 and MEC-10. An additional protein, the paraoxonase-like protein MEC-6, is essential for transduction, and previous work suggested that MEC-6 was part of the transduction complex. We found that MEC-6 and a similar protein, POML-1, reside primarily in the endoplasmic reticulum and do not colocalize with MEC-4 on the plasma membrane in vivo. As with MEC-6, POML-1 is needed for touch sensitivity, the neurodegeneration caused by the mec-4(d) mutation, and the expression and distribution of MEC-4 in vivo. Both proteins are likely needed for the proper folding or assembly of MEC-4 channels in vivo as measured by FRET. MEC-6 detectably increases the rate of MEC-4 accumulation on the Xenopus oocyte plasma membrane. These results suggest that MEC-6 and POML-1 interact with MEC-4 to facilitate expression and localization of MEC-4 on the cell surface. Thus MEC-6 and POML-1 act more like chaperones for MEC-4 than channel components.
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Affiliation(s)
- Yushu Chen
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Shashank Bharill
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720
| | - Zeynep Altun
- Department of Neuroscience and Psychiatry, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Robert O'Hagan
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Brian Coblitz
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Ehud Y Isacoff
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720
| | - Martin Chalfie
- Department of Biological Sciences, Columbia University, New York, NY 10027
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22
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Feng G, Long Y, Peng J, Li Q, Cui Z. Transcriptomic characterization of the dorsal lobes after hepatectomy of the ventral lobe in zebrafish. BMC Genomics 2015; 16:979. [PMID: 26584608 PMCID: PMC4653908 DOI: 10.1186/s12864-015-2145-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/26/2015] [Indexed: 02/08/2023] Open
Abstract
Background The liver possesses an ability of compensatory growth after removing three of five lobes in mammals or one of three lobes in zebrafish. The reenter of hepatocytes into the cell cycle is one of the hallmarks for the initiation of liver compensatory growth, but cellular and molecular mechanisms underlying the activation of hepatocytes remain largely unknown. Results To better understand the process, transcriptional profiles of the remaining liver dorsal lobes in female zebrafish were generated with RNA-seq. About 44 million raw reads were obtained from three sequencing libraries and 71 % of raw reads were mapped to the reference genome of zebrafish. A total number of 5652 genes were differentially expressed in at least one of two time points during the compensatory growth of liver dorsal lobes and classified into different functional categories. A number of genes encoding angiogenesis-related growth factors/ligands and apoptosis-associated cytokines were strongly expressed at 6-h time point after the removal of the ventral lobe. Gene ontology enrichment analysis of genes up-regulated during early stages of liver compensatory growth revealed that small GTPase-mediated signal transduction, RNA processing and intracellular protein transport were the most highly overrepresented biological processes and SNARE interactions in vesicular transport, proteasome and basal transcription factors were the most highly enriched pathways. Moreover, 477 genes differently expressed during liver compensatory growth of both female zebrafish and mice were involved in the response to stimulus, DNA replication, metabolic processes of fatty acid, lipid and steroid, multicellular organismal homeostasis and extracellular matrix constituent secretion. Conclusions Multiple biological processes and signaling pathways are immediately activated in remaining dorsal lobes of female zebrafish right after removal of the ventral lobe and these findings provide crucial clues for further identification of cis-elements and trans-factors that are extensively involved in the initiation of liver compensatory growth. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2145-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Guohui Feng
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, Hubei, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Yong Long
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, Hubei, China.
| | - Jinrong Peng
- Zhejiang University, Hangzhou, 310058, Zhejiang, China.
| | - Qing Li
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, Hubei, China.
| | - Zongbin Cui
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, Hubei, China.
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23
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Tam JHK, Pasternak SH. Imaging the Intracellular Trafficking of APP with Photoactivatable GFP. J Vis Exp 2015:e53153. [PMID: 26555118 DOI: 10.3791/53153] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Beta-amyloid (Aβ) is the major constituent of senile plaques found in the brains of Alzheimer's disease patients. Aβ is derived from the sequential cleavage of Amyloid Precursor Protein (APP) by β and γ-secretases. Despite the importance of Aβ to AD pathology, the subcellular localization of these cleavages is not well established. Work in our laboratory and others implicate the endosomal/lysosomal system in APP processing after internalization from the cell surface. However, the intracellular trafficking of APP is relatively understudied. While cell-surface proteins are amendable to many labeling techniques, there are no simple methods for following the trafficking of membrane proteins from the Golgi. To this end, we created APP constructs that were tagged with photo-activatable GFP (paGFP) at the C-terminus. After synthesis, paGFP has low basal fluorescence, but it can be stimulated with 413 nm light to produce a strong, stable green fluorescence. By using the Golgi marker Galactosyl transferase coupled to Cyan Fluorescent Protein (GalT-CFP) as a target, we are able to accurately photoactivate APP in the trans-Golgi network. Photo-activated APP-paGFP can then be followed as it traffics to downstream compartments identified with fluorescently tagged compartment marker proteins for the early endosome (Rab5), the late endosome (Rab9) and the lysosome (LAMP1). Furthermore, using inhibitors to APP processing including chloroquine or the γ-secretase inhibitor L685, 458, we are able to perform pulse-chase experiments to examine the processing of APP in single cells. We find that a large fraction of APP moves rapidly to the lysosome without appearing at the cell surface, and is then cleared from the lysosome by secretase-like cleavages. This technique demonstrates the utility of paGFP for following the trafficking and processing of intracellular proteins from the Golgi to downstream compartments.
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Affiliation(s)
- Joshua H K Tam
- Department of Physiology and Pharmacology, Robarts Research Institute, Western University
| | - Stephen H Pasternak
- Department of Physiology and Pharmacology, Robarts Research Institute, Western University; Department of Clinical Neurological Sciences, Western University;
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24
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Park BC, Yim YI, Zhao X, Olszewski MB, Eisenberg E, Greene LE. The clathrin-binding and J-domains of GAK support the uncoating and chaperoning of clathrin by Hsc70 in the brain. J Cell Sci 2015; 128:3811-21. [PMID: 26345367 DOI: 10.1242/jcs.171058] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 08/27/2015] [Indexed: 12/19/2022] Open
Abstract
Cyclin-G-associated kinase (GAK), the ubiquitously expressed J-domain protein, is essential for the chaperoning and uncoating of clathrin that is mediated by Hsc70 (also known as HSPA8). Adjacent to the C-terminal J-domain that binds to Hsc70, GAK has a clathrin-binding domain that is linked to an N-terminal kinase domain through a PTEN-like domain. Knocking out GAK in fibroblasts caused inhibition of clathrin-dependent trafficking, which was rescued by expressing a 62-kDa fragment of GAK, comprising just the clathrin-binding and J-domains. Expressing this fragment as a transgene in mice rescued the lethality and the histological defects caused by knocking out GAK in the liver or in the brain. Furthermore, when both GAK and auxilin (also known as DNAJC6), the neuronal-specific homolog of GAK, were knocked out in the brain, mice expressing the 62-kDa GAK fragment were viable, lived a normal life-span and had no major behavior abnormalities. However, these mice were about half the size of wild-type mice. Therefore, the PTEN-like domains of GAK and auxilin are not essential for Hsc70-dependent chaperoning and uncoating of clathrin, but depending on the tissue, these domains appear to increase the efficiency of these co-chaperones.
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Affiliation(s)
- Bum-Chan Park
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yang-In Yim
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xiaohong Zhao
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Maciej B Olszewski
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Evan Eisenberg
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lois E Greene
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
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25
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Pagani A, Vieillevoye M, Nai A, Rausa M, Ladli M, Lacombe C, Mayeux P, Verdier F, Camaschella C, Silvestri L. Regulation of cell surface transferrin receptor-2 by iron-dependent cleavage and release of a soluble form. Haematologica 2015; 100:458-65. [PMID: 25637053 DOI: 10.3324/haematol.2014.118521] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Transferrin receptor-2 is a transmembrane protein whose expression is restricted to hepatocytes and erythroid cells. Transferrin receptor-2 has a regulatory function in iron homeostasis, since its inactivation causes systemic iron overload. Hepatic transferrin receptor-2 participates in iron sensing and is involved in hepcidin activation, although the mechanism remains unclear. Erythroid transferrin receptor-2 associates with and stabilizes erythropoietin receptors on the erythroblast surface and is essential to control erythrocyte production in iron deficiency. We identified a soluble form of transferrin receptor-2 in the media of transfected cells and showed that cultured human erythroid cells release an endogenous soluble form. Soluble transferrin receptor-2 originates from a cleavage of the cell surface protein, which is inhibited by diferric transferrin in a dose-dependent manner. Accordingly, the shedding of the transferrin receptor-2 variant G679A, mutated in the Arginine-Glycine-Aspartic acid motif and unable to bind diferric transferrin, is not modulated by the ligand. This observation links the process of transferrin receptor-2 removal from the plasma membrane to iron homeostasis. Soluble transferrin receptor-2 does not affect the binding of erythropoietin to erythropoietin receptor or the consequent signaling and partially inhibits hepcidin promoter activation only in vitro. Whether it is a component of the signals released by erythropoiesis in iron deficiency remains to be investigated. Our results indicate that membrane transferrin receptor-2, a sensor of circulating iron, is released from the cell membrane in iron deficiency.
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Affiliation(s)
- Alessia Pagani
- Vita Salute San Raffaele University, Milan, Italy Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maud Vieillevoye
- Institut Cochin, INSERM, U1016, Université Paris Descartes, CNRS (UMR8104), Paris, France Ligue National contre le Cancer, Paris, France
| | - Antonella Nai
- Vita Salute San Raffaele University, Milan, Italy Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Marco Rausa
- Vita Salute San Raffaele University, Milan, Italy Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Meriem Ladli
- Institut Cochin, INSERM, U1016, Université Paris Descartes, CNRS (UMR8104), Paris, France Ligue National contre le Cancer, Paris, France
| | - Catherine Lacombe
- Institut Cochin, INSERM, U1016, Université Paris Descartes, CNRS (UMR8104), Paris, France Ligue National contre le Cancer, Paris, France
| | - Patrick Mayeux
- Institut Cochin, INSERM, U1016, Université Paris Descartes, CNRS (UMR8104), Paris, France Ligue National contre le Cancer, Paris, France
| | | | - Clara Camaschella
- Vita Salute San Raffaele University, Milan, Italy Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Laura Silvestri
- Vita Salute San Raffaele University, Milan, Italy Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
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26
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Albrecht T, Zhao Y, Nguyen TH, Campbell RE, Johnson JD. Fluorescent biosensors illuminate calcium levels within defined beta-cell endosome subpopulations. Cell Calcium 2015; 57:263-74. [PMID: 25682167 DOI: 10.1016/j.ceca.2015.01.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 12/26/2014] [Accepted: 01/19/2015] [Indexed: 11/18/2022]
Abstract
Live cell imaging has revealed that calcium ions (Ca(2+)) pass in and out of many cellular organelles. However, technical hurdles have limited measurements of Ca(2+) in acidic organelles, such as endosomes. Although evidence hints that endosomes play a role in Ca(2+) signaling, direct measurements within endosomal lumina represent one of the final frontiers in organelle imaging. To measure Ca(2+) in a TiVAMP-positive endosome sub-population, the pH-resistant ratiometric Ca(2+) biosensor GEM-GECO1 and the ratiometric pH biosensor mKeima were used. A positive correlation between acidic endosomal pH and higher Ca(2+) was observed within these Rab5a- and Rab7-positive compartments. Ca(2+) concentration in most endosomes was estimated to be below 2μM, lower than Ca(2+) levels in several other intracellular stores, indicating that endosomes may take up Ca(2+) during physiological stimulation. Indeed, endosomes accumulated Ca(2+) during glucose-stimulation, a condition where endosomal pH did not change. Our biosensors permitted the first measurements revealing a role for endosomes in cellular Ca(2+) homeostasis during physiological stimulation.
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Affiliation(s)
- Tobias Albrecht
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Yongxin Zhao
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Trang Hai Nguyen
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Robert E Campbell
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - James D Johnson
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada.
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27
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Haghi M, Ong HX, Traini D, Young P. Across the pulmonary epithelial barrier: Integration of physicochemical properties and human cell models to study pulmonary drug formulations. Pharmacol Ther 2014; 144:235-52. [DOI: 10.1016/j.pharmthera.2014.05.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 04/30/2014] [Indexed: 11/16/2022]
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28
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Kienzle C, von Blume J. Secretory cargo sorting at the trans-Golgi network. Trends Cell Biol 2014; 24:584-93. [DOI: 10.1016/j.tcb.2014.04.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 04/15/2014] [Accepted: 04/16/2014] [Indexed: 12/22/2022]
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29
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Exocytosis of nanoparticles from cells: role in cellular retention and toxicity. Adv Colloid Interface Sci 2013; 201-202:18-29. [PMID: 24200091 DOI: 10.1016/j.cis.2013.10.013] [Citation(s) in RCA: 186] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 10/11/2013] [Accepted: 10/13/2013] [Indexed: 01/06/2023]
Abstract
Over the past decade, nanoparticles (NPs) have been increasingly developed in various biomedical applications such as cell tracking, biosensing, contrast imaging, targeted drug delivery, and tissue engineering. Their versatility in design and function has made them an attractive, alternative choice in many biological and biomedical applications. Cellular responses to NPs, their uptake, and adverse biological effects caused by NPs are rapidly-growing research niches. However, NP excretion and its underlying mechanisms and cell signaling pathways are yet elusive. In this review, we present an overview of how NPs are handled intracellularly and how they are excreted from cells following the uptake. We also discuss how exocytosis of nanomaterials impacts both the therapeutic delivery of nanoscale objects and their nanotoxicology.
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30
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Hu G, Suo Y, Huang J. A crucial role of the RGS domain in trans-Golgi network export of AtRGS1 in the protein secretory pathway. MOLECULAR PLANT 2013; 6:1933-1944. [PMID: 23793400 DOI: 10.1093/mp/sst109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The secretory pathway is responsible for the transport of newly synthesized transmembrane proteins from the endoplasmic reticulum to their destinations via the Golgi/trans-Golgi network (TGN). Cargo proteins at each station are actively sorted by specific sorting signals on the cargo and the corresponding coat complexes. Here, we used the Arabidopsis regulator of G-protein signaling (AtRGS1), which contains an N-terminal potentially sensing glucose seven-transmembrane domain and a C-terminal RGS domain, as a model to uncover sorting motifs required for its cell surface expression. Expression of wild-type and truncated or mutated AtRGS1 fluorescent fusion proteins identified two cysteine residues in the extracellular N-terminus that are essential for endoplasmic reticulum exit and/or correct folding of AtRGS1. The linker between the seven-transmembrane and RGS domains contains an endoplasmic reticulum export signal, whereas the C-terminus is dispensable for the plasma membrane expression of AtRGS1. Interestingly, deletion of the RGS domain results in Golgi/TGN localization of the truncated AtRGS1. Further analysis using site-directed mutagenesis showed that a tyrosine-based motif embedded in the RGS domain is essential for Golgi/TGN export of AtRGS1. These results reveal a new role for the RGS domain in regulating AtRGS1 trafficking from the Golgi/TGN to the plasma membrane and explain the interaction between the seven-transmembrane and RGS domains.
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Affiliation(s)
- Guangzhen Hu
- National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Feng Lin Road, Shanghai 200032, China
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31
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Martínez-Alonso E, Tomás M, Martínez-Menárguez JA. Morpho-functional architecture of the Golgi complex of neuroendocrine cells. Front Endocrinol (Lausanne) 2013; 4:41. [PMID: 23543640 PMCID: PMC3610015 DOI: 10.3389/fendo.2013.00041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 03/14/2013] [Indexed: 12/22/2022] Open
Abstract
In neuroendocrine cells, prohormones move from the endoplasmic reticulum to the Golgi complex (GC), where they are sorted and packed into secretory granules. The GC is considered the central station of the secretory pathway of proteins and lipids en route to their final destination. In most mammalian cells, it is formed by several stacks of cisternae connected by tubules, forming a continuous ribbon. This organelle shows an extraordinary structural and functional complexity, which is exacerbated by the fact that its architecture is cell type specific and also tuned by the functional status of the cell. It is, indeed, one the most beautiful cellular organelles and, for that reason, perhaps the most extensively photographed by electron microscopists. In recent decades, an exhaustive dissection of the molecular machinery involved in membrane traffic and other Golgi functions has been carried out. Concomitantly, detailed morphological studies have been performed, including 3D analysis by electron tomography, and the precise location of key proteins has been identified by immunoelectron microscopy. Despite all this effort, some basic aspects of Golgi functioning remain unsolved. For instance, the mode of intra-Golgi transport is not known, and two opposing theories (vesicular transport and cisternal maturation models) have polarized the field for many years. Neither of these theories explains all the experimental data so that new theories and combinations thereof have recently been proposed. Moreover, the specific role of the small vesicles and tubules which surround the stacks needs to be clarified. In this review, we summarize our current knowledge of the Golgi architecture in relation with its function and the mechanisms of intra-Golgi transport. Within the same framework, the characteristics of the GC of neuroendocrine cells are analyzed.
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Affiliation(s)
- Emma Martínez-Alonso
- Department of Cell Biology and Histology, Medical School, University of MurciaMurcia, Spain
| | - Mónica Tomás
- Department of Human Anatomy and Embryology, Medical School, Valencia UniversityValencia, Spain
| | - José A. Martínez-Menárguez
- Department of Cell Biology and Histology, Medical School, University of MurciaMurcia, Spain
- *Correspondence: José A. Martínez-Menárguez, Department of Cell Biology and Histology, Medical School, University of Murcia, 30100 Murcia, Spain. e-mail:
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32
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Cottam NP, Ungar D. Retrograde vesicle transport in the Golgi. PROTOPLASMA 2012; 249:943-55. [PMID: 22160157 DOI: 10.1007/s00709-011-0361-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 11/29/2011] [Indexed: 05/23/2023]
Abstract
The Golgi apparatus is the central sorting and biosynthesis hub of the secretory pathway, and uses vesicle transport for the recycling of its resident enzymes. This system must operate with high fidelity and efficiency for the correct modification of secretory glycoconjugates. In this review, we discuss recent advances on how coats, tethers, Rabs and SNAREs cooperate at the Golgi to achieve vesicle transport. We cover the well understood vesicle formation process orchestrated by the COPI coat, and the comprehensively documented fusion process governed by a set of Golgi localised SNAREs. Much less clear are the steps in-between formation and fusion of vesicles, and we therefore provide a much needed update of the latest findings about vesicle tethering. The interplay between Rab GTPases, golgin family coiled-coil tethers and the conserved oligomeric Golgi (COG) complex at the Golgi are thoroughly evaluated.
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Affiliation(s)
- Nathanael P Cottam
- Department of Biology (Area 9), University of York, Heslington, York, YO10 5DD, UK
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33
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Gupta GS. P-Type Lectins: Cation-Dependent Mannose-6-Phosphate Receptor. ANIMAL LECTINS: FORM, FUNCTION AND CLINICAL APPLICATIONS 2012. [PMCID: PMC7121444 DOI: 10.1007/978-3-7091-1065-2_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In eukaryotic cells, post-translational modification of secreted proteins and intracellular protein transport between organelles are ubiquitous features. One of the most studied systems is the N-linked glycosylation pathway in the synthesis of secreted glycoproteins (Schrag et al. 2003). The N-linked glycoproteins are subjected to diverse modifications and are transported through ER and Golgi apparatus to their final destinations in- and outside the cell. Incorporation of cargo glycoproteins into transport vesicles is mediated by transmembrane cargo receptors, which have been identified as intracellular lectins. For example, mannose 6-phosphate receptors (Ghosh et al. 2003) function as a cargo receptor for lysosomal proteins in the trans-Golgi network, whereas ERGIC-53 (Zhang et al. 2003) and its yeast orthologs Emp46/47p (Sato and Nakano 2002) are transport lectins for glycoproteins that are transported out of ER.
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Affiliation(s)
- G. S. Gupta
- Department of Biophysics, Punjab University, Chandigarh, India
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34
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Surma MA, Klose C, Simons K. Lipid-dependent protein sorting at the trans-Golgi network. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:1059-67. [PMID: 22230596 DOI: 10.1016/j.bbalip.2011.12.008] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 12/02/2011] [Accepted: 12/03/2011] [Indexed: 12/14/2022]
Abstract
In eukaryotic cells, the trans-Golgi network serves as a sorting station for post-Golgi traffic. In addition to coat- and adaptor-mediated mechanisms, studies in mammalian epithelial cells and yeast have provided evidence for lipid-dependent protein sorting as a major delivery mechanism for cargo sorting to the cell surface. The mechanism for lipid-mediated sorting is the generation of raft platforms of sphingolipids, sterols and specific sets of cargo proteins by phase segregation in the TGN. Here, we review the evidence for such lipid-raft-based sorting at the TGN, as well as their involvement in the formation of TGN-to-PM transport carriers. This article is part of a Special Issue entitled Lipids and Vesicular Transport.
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Affiliation(s)
- Michal A Surma
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
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35
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Zhi P, Chia PZC, Chia C, Gleeson PA. Intracellular trafficking of the β-secretase and processing of amyloid precursor protein. IUBMB Life 2011; 63:721-9. [PMID: 21834057 DOI: 10.1002/iub.512] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 05/11/2011] [Indexed: 12/15/2022]
Abstract
The main component of the amyloid plaques found in the brains of those with Alzheimer's disease (AD) is a polymerized form of the β-amyloid peptide (Aβ) and is considered to play a central role in the pathogenesis of this neurodegenerative disorder. Aβ is derived from the proteolytic processing of the amyloid precursor protein (APP). Beta site APP-cleaving enzyme, BACE1 (also known as β-secretase) is a membrane-bound aspartyl protease responsible for the initial step in the generation of Aβ peptide and is thus a prime target for therapeutic intervention. Substantive evidence now indicates that the processing of APP by BACE1 is regulated by the intracellular sorting of the enzyme and, moreover, perturbations in these intracellular trafficking pathways have been linked to late-onset AD. In this review, we highlight the recent advances in the understanding of the regulation of the intracellular sorting of BACE1 and APP and illustrate why the trafficking of these cargos represent a key issue for understanding the membrane-mediated events associated with the generation of the neurotoxic Aβ products in AD.
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Affiliation(s)
- Pei Zhi
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, Australia
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36
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Abstract
Since its first visualization in 1898, the Golgi has been a topic of intense morphological research. A typical mammalian Golgi consists of a pile of stapled cisternae, the Golgi stack, which is a key station for modification of newly synthesized proteins and lipids. Distinct stacks are interconnected by tubules to form the Golgi ribbon. At the entrance site of the Golgi, the cis-Golgi, vesicular tubular clusters (VTCs) form the intermediate between the endoplasmic reticulum and the Golgi stack. At the exit site of the Golgi, the trans-Golgi, the trans-Golgi network (TGN) is the major site of sorting proteins to distinct cellular locations. Golgi functioning can only be understood in light of its complex architecture, as was revealed by a range of distinct electron microscopy (EM) approaches. In this article, a general concept of mammalian Golgi architecture, including VTCs and the TGN, is described.
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Affiliation(s)
- Judith Klumperman
- Department of Cell Biology, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands.
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37
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Halwachs S, Schaefer I, Seibel P, Honscha W. Antiepileptic Drugs Reduce the Efficacy of Methotrexate Chemotherapy through Accelerated Degradation of the Reduced Folate Carrier by the Ubiquitin-Proteasome Pathway. Chemotherapy 2011; 57:345-56. [DOI: 10.1159/000330461] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 04/07/2011] [Indexed: 12/11/2022]
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38
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Crivellato E, Nico B, Gallo VP, Ribatti D. Cell secretion mediated by granule-associated vesicle transport: a glimpse at evolution. Anat Rec (Hoboken) 2010; 293:1115-24. [PMID: 20340095 DOI: 10.1002/ar.21146] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Regulated secretion allows extrusion of cell products stored in specialized membrane-bound organelles called secretory granules or secretory vesicles. Regulated secretion provides basic functions in living organisms, and in a phylogenetic perspective, it is recognizable in the most primitive eukaryotic forms. This article is an attempt to trace the evolutionary history of a special type of secretory pattern, which has been referred to as vesicle-mediated degranulation or piecemeal degranulation (PMD). First described in the early 70s of the last century in inflammatory cells, such as the basophils, mast cells, and eosinophils, this regulated secretory route has subsequently been recognized in endocrine cells, in particular in the chromaffin cells of the adrenal medulla. This vesicle-mediated degranulation is held to mobilize small and specific aliquots of granule-associated material for selective paracrine or endocrine transport to the cell exterior. PMD has been identified in many vertebrate classes. By contrast, no data are available for invertebrates. We speculate that this pattern of cell secretion emerged early in phylogenesis, when the first metazoans appeared. In this review article, we will first revise the concept of vesicle-mediated degranulation in the light of the most recent experimental discoveries and theoretical implications. Then, the distribution of this secretory mode among vertebrates and its molecular basis will be highlighted. Finally, the potential occurrence of PMD in invertebrates, its biological significance from an evolutionary perspective and the future direction of investigations will be briefly sketched.
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Affiliation(s)
- Enrico Crivellato
- Department of Medical and Morphological Research, Section of Anatomy, University of Udine School of Medicine, Udine, Italy.
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39
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TGN golgins, Rabs and cytoskeleton: regulating the Golgi trafficking highways. Trends Cell Biol 2010; 20:329-36. [DOI: 10.1016/j.tcb.2010.02.006] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2009] [Revised: 02/15/2010] [Accepted: 02/17/2010] [Indexed: 12/22/2022]
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40
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Wang Y, Tai G, Lu L, Johannes L, Hong W, Tang BL. Trans-Golgi network syntaxin 10 functions distinctly from syntaxins 6 and 16. Mol Membr Biol 2009; 22:313-25. [PMID: 16154903 DOI: 10.1080/09687860500143829] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Syntaxin 10 is a soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) protein localized to the trans-Golgi network (TGN), where two other members of the syntaxin family, syntaxins 6 and 16, also reside. The role of syntaxin 10 in regulating TGN protein traffic is not yet defined. Syntaxin 10 co-localizes well with syntaxins 6 and 16 at the TGN in interphase cells, and appears to interact with both syntaxin 6 and 16 as evidenced by co-immunoprecipitation analyses. However, unlike syntaxin 6 and 16, neither syntaxin 10 antibodies nor its cytosolic domain inhibits endosome-TGN transport of shiga toxin. Syntaxin 16 knockdown with small interfering RNA (siRNA) affects the TGN localization of syntaxin 6 but not syntaxin 10, and clearly inhibits endosome-TGN transport. On the other hand, knockdown of syntaxin 10 expressions had no significant effect on the TGN localization of syntaxin 6 and 16, and did not inhibit endosome-TGN transport. Unlike syntaxin 16, syntaxin 10 does not interact specifically with Vps45, the Sec1/Munc18 (SM) family member at the TGN. On the other hand, syntaxin 10 reciprocally co-immunoprecipitated endosomal syntaxin 12/13, and knockdown of syntaxin 10 expressions affects the surface expression of transferrin receptor (TfR) and seems to induce the formation of an immobile TfR pool. Therefore, in spite of its co-localization and possible interaction with syntaxin 16, syntaxin 10 is not part of the syntaxin 16-based SNARE complex involved in endosome-TGN transport, and may have a hitherto unrecognized function in the TGN-endosome boundary.
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Affiliation(s)
- Ya Wang
- Department of Biochemistry and Neurobiology Program, National University of Singapore, MD7, 8 Medical Drive, Singapore, 117597, Republic of Singapore
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41
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Cross-talk between endocytic clearance and secretion in macrophages. Immunobiology 2009; 214:576-93. [DOI: 10.1016/j.imbio.2009.03.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 03/16/2009] [Indexed: 12/20/2022]
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42
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Klemm RW, Ejsing CS, Surma MA, Kaiser HJ, Gerl MJ, Sampaio JL, de Robillard Q, Ferguson C, Proszynski TJ, Shevchenko A, Simons K. Segregation of sphingolipids and sterols during formation of secretory vesicles at the trans-Golgi network. ACTA ACUST UNITED AC 2009; 185:601-12. [PMID: 19433450 PMCID: PMC2711577 DOI: 10.1083/jcb.200901145] [Citation(s) in RCA: 479] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The trans-Golgi network (TGN) is the major sorting station in the secretory pathway of all eukaryotic cells. How the TGN sorts proteins and lipids to generate the enrichment of sphingolipids and sterols at the plasma membrane is poorly understood. To address this fundamental question in membrane trafficking, we devised an immunoisolation procedure for specific recovery of post-Golgi secretory vesicles transporting a transmembrane raft protein from the TGN to the cell surface in the yeast Saccharomyces cerevisiae. Using a novel quantitative shotgun lipidomics approach, we could demonstrate that TGN sorting selectively enriched ergosterol and sphingolipid species in the immunoisolated secretory vesicles. This finding, for the first time, indicates that the TGN exhibits the capacity to sort membrane lipids. Furthermore, the observation that the immunoisolated vesicles exhibited a higher membrane order than the late Golgi membrane, as measured by C-Laurdan spectrophotometry, strongly suggests that lipid rafts play a role in the TGN-sorting machinery.
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Affiliation(s)
- Robin W Klemm
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
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43
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Antiepileptic drugs reduce efficacy of methotrexate chemotherapy by downregulation of Reduced folate carrier transport activity. Leukemia 2009; 23:1087-97. [DOI: 10.1038/leu.2009.6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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44
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Ludwig A, Blume J, Diep TM, Yuan J, Mateos JM, Leuthäuser K, Steuble M, Streit P, Sonderegger P. Calsyntenins mediate TGN exit of APP in a kinesin-1-dependent manner. Traffic 2009; 10:572-89. [PMID: 19192245 DOI: 10.1111/j.1600-0854.2009.00886.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Kinesin motors are required for the export of membranous cargo from the trans-Golgi network (TGN), yet information about how kinesins are recruited to forming transport intermediates is sparse. Here we show that the Kinesin-1 docking protein calsyntenin-1 localizes to the TGN in vivo and directly and specifically recruits Kinesin-1 to Golgi/TGN membranes as well as to dynamic post-Golgi carriers. Overexpression of various calsyntenin chimeras and kinesin light chain 1 (KLC1) at high levels caused the formation of aberrant membrane stacks at the endoplasmic reticulum (ER) or the Golgi, disrupted overall Golgi structure and blocked exit of calsyntenin from the TGN. Intriguingly, this blockade of calsyntenin exit strongly and selectively impeded TGN exit of amyloid precursor protein (APP). Using live cell microscopy we found that calsyntenins exit the TGN in Kinesin-1-decorated tubular structures which may serve as carriers for calsyntenin-1-mediated post-TGN transport of APP. Abrogation of this pathway via virus-mediated knockdown of calsyntenin-1 expression in primary cultured neurons caused a marked elevation of APP C-terminal fragments. Together, these results indicate a role for calsyntenin-1 in Kinesin-1-dependent TGN exit and post-Golgi transport of APP-containing organelles and further suggest that distinct intracellular routes may exhibit different capacities for proteolytic processing of APP.
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Affiliation(s)
- Alexander Ludwig
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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45
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Figueredo SM, Weeks CS, Young SK, Ouellette AJ. Anionic amino acids near the pro-alpha-defensin N terminus mediate inhibition of bactericidal activity in mouse pro-cryptdin-4. J Biol Chem 2008; 284:6826-31. [PMID: 19106102 DOI: 10.1074/jbc.m807024200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In mouse Paneth cells, alpha-defensins, termed cryptdins (Crps), are activated by matrix metalloproteinase-7-mediated proteolysis of inactive precursors (pro-Crps) to bactericidal forms. The activating cleavage step at Ser(43) downward arrow Ile(44) in mouse pro-Crp4-(20-92) removes nine acidic amino acids that collectively block the membrane-disruptive behavior of the Crp4 moiety of the proform. This inhibitory mechanism has been investigated further to identify whether specific cluster(s) of electronegative amino acids in pro-Crp4-(20-43) are responsible for blocking bactericidal activity and membrane disruption. To test whether specific cluster(s) of electronegative amino acids in pro-Crp4-(20-43) have specific positional effects that block bactericidal peptide activity and membrane disruption, acidic residues positioned at the distal (Asp(20), Asp(26), Glu(27), and Glu(28)), mid (Glu(32) and Glu(33)), and proximal (Glu(37), Glu(38), and Asp(39)) clusters in pro-Crp4-(20-92) were mutagenized, and variants were assayed for differential effects of mutagenesis on bactericidal peptide activity. Substitution of the mid and proximal Asp and Glu clusters with Gly produced additive effects with respect to the induction of both bactericidal activity and membrane permeabilization of live Escherichia coli ML35 cells. In contrast, substitution of distal Glu and Asp residues with Gly or their deletion resulted in pro-Crp4-(20-92) variants with bactericidal and membrane-disruptive activities equal to or greater than that of fully mature Crp4. These findings support the conclusion that the most distal N-terminal anionic residues of pro-Crp4-(20-92) are primarily responsible for blocking Crp4-mediated membrane disruption in the precursor.
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Affiliation(s)
- Sharel M Figueredo
- Department of Pathology and Laboratory Medicine, University of California, Irvine, California 92697-4800, USA
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46
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Basovskiy YI, Shkarupeta MM, Levitskiy SA, Kostryukova ES, Lazarev VN, Govorun VM. Hydrophobic domains determine localization of IncC and IncG full-length proteins of C. trachomatis during their expression in cultured HeLa cells. Bull Exp Biol Med 2008; 145:425-9. [DOI: 10.1007/s10517-008-0108-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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47
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Boonen M, Rezende de Castro R, Cuvelier G, Hamer I, Jadot M. A dileucine signal situated in the C-terminal tail of the lysosomal membrane protein p40 is responsible for its targeting to lysosomes. Biochem J 2008; 414:431-40. [PMID: 18479248 DOI: 10.1042/bj20071626] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Transport of newly synthesized lysosomal membrane proteins from the TGN (trans-Golgi network) to the lysosomes is due to the presence of specific signals in their cytoplasmic domains that are recognized by cytosolic adaptors. p40, a hypothetical transporter of 372 amino acids localized in the lysosomal membrane, contains four putative lysosomal sorting motifs in its sequence: three of the YXXphi-type (Y(6)QLF, Y(106)VAL, Y(333)NGL) and one of the [D/E]XXXL[L/I]-type (EQERL(360)L(361)). To test the role of these motifs in the biosynthetic transport of p40, we replaced the most critical residues of these consensus sequences, the tyrosine residue or the leucine-leucine pair, by alanine or alanine-valine respectively. We analysed the subcellular localization of the mutated p40 proteins in transfected HeLa cells by confocal microscopy and by biochemical approaches (subcellular fractionation on self-forming Percoll density gradients and cell surface biotinylation). The results of the present study show that p40 is mistargeted to the plasma membrane when its dileucine motif is disrupted. No role of the tyrosine motifs could be put forward. Taken together, our results provide evidence that the sorting of p40 from the TGN to the lysosomes is directed by the dileucine EQERL(360)L(361) motif situated in its C-terminal tail.
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Affiliation(s)
- Marielle Boonen
- URPhiM, Laboratoire de Chimie Physiologique, FUNDP, B-5000 Namur, Belgium
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48
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Lee I, Drake MT, Traub LM, Kornfeld S. Cargo-sorting signals promote polymerization of adaptor protein-1 in an Arf-1.GTP-independent manner. Arch Biochem Biophys 2008; 479:63-8. [PMID: 18762162 DOI: 10.1016/j.abb.2008.08.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 08/06/2008] [Accepted: 08/10/2008] [Indexed: 10/21/2022]
Abstract
Adaptor protein-1 (AP-1) is recruited onto the trans-Golgi network via binding to Arf-1.GTP, cargo-sorting signals and phosphoinositides, where it orchestrates the assembly of clathrin-coated vesicular carriers that transport cargo molecules to endosomes. Here we show that cytosolic AP-1 polymerizes when recruited onto enriched Golgi membranes and liposomes containing covalently attached cargo-sorting signal peptides. Incubation of cytosolic or purified AP-1 with soluble sorting signal peptides also resulted in AP-1 polymerization, showing that Arf-1.GTP and membranes are not required for this process. We propose that cargo-induced polymerization of AP-1 contributes to stabilization of the coat complex in the formation of clathrin-coated buds.
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Affiliation(s)
- Intaek Lee
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
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49
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Giordano T, Brigatti C, Podini P, Bonifacio E, Meldolesi J, Malosio ML. Beta cell chromogranin B is partially segregated in distinct granules and can be released separately from insulin in response to stimulation. Diabetologia 2008; 51:997-1007. [PMID: 18437352 DOI: 10.1007/s00125-008-0980-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 02/08/2008] [Indexed: 12/22/2022]
Abstract
AIMS/HYPOTHESIS We investigated, in three beta cell lines (INS-1E, RIN-5AH, betaTC3) and in human and rodent primary beta cells, the storage and release of chromogranin B, a secretory protein expressed in beta cells and postulated to play an autocrine role. We asked whether chromogranin B is stored together with and discharged in constant ratio to insulin upon various stimuli. METHODS The intracellular distribution of insulin and chromogranin B was revealed by immunofluorescence followed by three-dimensional image reconstruction and by immunoelectron microscopy; their stimulated discharge was measured by ELISA and immunoblot analysis of homogenates and incubation media. RESULTS Insulin and chromogranin B, co-localised in the Golgi complex/trans-Golgi network, appeared largely segregated from each other in the secretory granule compartment. In INS-1E cells, the percentage of granules positive only for insulin or chromogranin B and of those positive for both was 66, 7 and 27%, respectively. In resting cells, both insulin and chromogranin B were concentrated in the granule cores; upon stimulation, chromogranin B (but not insulin) was largely redistributed to the core periphery and the surrounding halo. Strong stimulation with a secretagogue mixture induced parallel release of insulin and chromogranin B, whereas with 3-isobutyl-1-methylxantine and forskolin +/- high glucose release of chromogranin B predominated. Weak, Ca(2+)-dependent stimulation with ionomycin or carbachol induced exclusive release of chromogranin B, suggesting a higher Ca(2+) sensitivity of the specific granules. CONCLUSIONS/INTERPRETATION The unexpected complexity of the beta cell granule population in terms of heterogeneity, molecular plasticity and the differential discharge, could play an important role in physiological control of insulin release and possibly also in beta cell pathology.
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Affiliation(s)
- T Giordano
- Immunology of Diabetes Research Unit, San Raffaele Scientific Institute, Via Olgettina, 60, 20132 Milan, Italy
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50
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Cao Z, Li C, Higginbotham JN, Franklin JL, Tabb DL, Graves-Deal R, Hill S, Cheek K, Jerome WG, Lapierre LA, Goldenring JR, Ham AJL, Coffey RJ. Use of fluorescence-activated vesicle sorting for isolation of Naked2-associated, basolaterally targeted exocytic vesicles for proteomics analysis. Mol Cell Proteomics 2008; 7:1651-67. [PMID: 18504258 DOI: 10.1074/mcp.m700155-mcp200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
By interacting with the cytoplasmic tail of a Golgi-processed form of transforming growth factor-alpha (TGFalpha), Naked2 coats TGFalpha-containing exocytic vesicles and directs them to the basolateral corner of polarized epithelial cells where the vesicles dock and fuse in a Naked2 myristoylation-dependent manner. These TGFalpha-containing Naked2-associated vesicles are not directed to the subapical Sec6/8 exocyst complex as has been reported for other basolateral cargo, and thus they appear to represent a distinct set of basolaterally targeted vesicles. To identify constituents of these vesicles, we exploited our finding that myristoylation-deficient Naked2 G2A vesicles are unable to fuse at the plasma membrane. Isolation of a population of myristoylation-deficient, green fluorescent protein-tagged G2A Naked2-associated vesicles was achieved by biochemical enrichment followed by flow cytometric fluorescence-activated vesicle sorting. The protein content of these plasma membrane de-enriched, flow-sorted fluorescent G2A Naked2 vesicles was determined by LC/LC-MS/MS analysis. Three independent isolations were performed, and 389 proteins were found in all three sets of G2A Naked2 vesicles. Rab10 and myosin IIA were identified as core machinery, and Na(+)/K(+)-ATPase alpha1 was identified as an additional cargo within these vesicles. As an initial validation step, we confirmed their presence and that of three additional proteins tested (annexin A1, annexin A2, and IQGAP1) in wild-type Naked2 vesicles. To our knowledge, this is the first large scale protein characterization of a population of basolaterally targeted exocytic vesicles and supports the use of fluorescence-activated vesicle sorting as a useful tool for isolation of cellular organelles for comprehensive proteomics analysis.
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Affiliation(s)
- Zheng Cao
- Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA
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