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Aba Ü, Maslak İC, İpşir C, Pehlivan D, Warnock NI, Tumes DJ, Cildir G, Erman B. A Novel Homozygous Germline Mutation in Transferrin Receptor 1 (TfR1) Leads to Combined Immunodeficiency and Provides New Insights into Iron-Immunity Axis. J Clin Immunol 2024; 44:55. [PMID: 38270687 PMCID: PMC10811203 DOI: 10.1007/s10875-024-01658-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 01/16/2024] [Indexed: 01/26/2024]
Abstract
A homozygous missense mutation in the transferrin receptor 1 (TfR1), also known as CD71, leads to a rare inborn error of immunity (IEI) characterized by the impaired lymphocyte activation and proliferation due to defective iron uptake of cells. However, only one causative mutation (c.58T > C, p.Y20H) in the TFRC gene coding for TfR1 has been reported so far. We herein identified a new disease-causing homozygous germline mutation in the TFRC gene (c.64C > T, p.R22W) (referred to as TfR1R22W from now on) in a Turkish patient with combined immunodeficiency (CID). TfR1R22W results in impaired TfR1 internalization similar to previously defined TfR1Y20H mutation. We found that TfR1R22W is associated with severely restricted B and T lymphocyte clonal diversity and impaired T cell activation and cytokine production as well as defective mitochondrial oxidative phosphorylation in helper T cells. In addition, circulating NK, Treg, and MAIT cell populations were significantly decreased in the patient. Using whole transcriptome analysis, we found dysregulated immune homeostasis and novel biological processes associated with TfR1R22W. We also identified a considerable expansion of circulating low-density neutrophils (LDNs) in patient's PBMCs. Overall, TfR1R22W mutation expands the current understanding of the IEI associated with TfR1 dysfunction and provides new insights underlying impaired immune function, lymphocyte diversity, and granulocyte homeostasis.
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Affiliation(s)
- Ümran Aba
- Department of Pediatric Immunology, Institute of Child Health, Hacettepe University, Ankara, Türkiye
- Can Sucak Research Laboratory for Translational Immunology, Hacettepe University, Ankara, Türkiye
| | - İbrahim Cemal Maslak
- Division of Pediatric Allergy and Immunology, Süleyman Demirel University, Isparta, Türkiye
| | - Canberk İpşir
- Department of Pediatric Immunology, Institute of Child Health, Hacettepe University, Ankara, Türkiye
- Can Sucak Research Laboratory for Translational Immunology, Hacettepe University, Ankara, Türkiye
| | - Damla Pehlivan
- Can Sucak Research Laboratory for Translational Immunology, Hacettepe University, Ankara, Türkiye
| | - Nicholas I Warnock
- Centre for Cancer Biology, SA Pathology and the University of South Australia, Adelaide, SA, 5000, Australia
| | - Damon J Tumes
- Centre for Cancer Biology, SA Pathology and the University of South Australia, Adelaide, SA, 5000, Australia
| | - Gökhan Cildir
- Centre for Cancer Biology, SA Pathology and the University of South Australia, Adelaide, SA, 5000, Australia.
- UniSA Bradley Building, North Terrace, Adelaide, SA, 5000, Australia.
| | - Baran Erman
- Can Sucak Research Laboratory for Translational Immunology, Hacettepe University, Ankara, Türkiye.
- Institute of Child Health, Hacettepe University, Ankara, Türkiye.
- Beytepe Campus of Hacettepe University, HUNITEK Building, Floor 1, 06800, Ankara, Türkiye.
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2
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Henke W, Kalamvoki M, Stephens EB. The Role of the Tyrosine-Based Sorting Signals of the ORF3a Protein of SARS-CoV-2 on Intracellular Trafficking, Autophagy, and Apoptosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.24.550379. [PMID: 37547007 PMCID: PMC10402054 DOI: 10.1101/2023.07.24.550379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
The open reading frame 3a (ORF3a) is an accessory transmembrane protein that is important to the pathogenicity of SARS-CoV-2. The cytoplasmic domain of ORF3a has three canonical tyrosine-based sorting signals (YxxΦ; where x is any amino acid and Φ is a hydrophobic amino acid with a bulky -R group). They have been implicated in the trafficking of membrane proteins to the cell plasma membrane and to intracellular organelles. Previous studies have indicated that mutation of the 160YSNV163 motif abrogated plasma membrane expression and inhibited ORF3a-induced apoptosis. However, two additional canonical tyrosine-based sorting motifs (211YYQL213, 233YNKI236) exist in the cytoplasmic domain of ORF3a that have not been assessed. We removed all three potential tyrosine-based motifs and systematically restored them to assess the importance of each motif or combination of motifs that restored efficient trafficking to the cell surface and lysosomes. Our results indicate that the YxxΦ motif at position 160 was insufficient for the trafficking of ORF3a to the cell surface. Our studies also showed that ORF3a proteins with an intact YxxΦ at position 211 or at 160 and 211 were most important. We found that ORF3a cell surface expression correlated with the co-localization of ORF3a with LAMP-1 near the cell surface. These results suggest that YxxΦ motifs within the cytoplasmic domain may act cooperatively in ORF3a transport to the plasma membrane and endocytosis to lysosomes. Further, our results indicate that certain tyrosine mutants failed to activate caspase 3 and did not correlate with autophagy functions associated with this protein.
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Affiliation(s)
- Wyatt Henke
- Department of Microbiology, Molecular Genetics, and Immunology, 2000 Hixon Hall, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, Kansas 66160
| | - Maria Kalamvoki
- Department of Microbiology, Molecular Genetics, and Immunology, 2000 Hixon Hall, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, Kansas 66160
| | - Edward B Stephens
- Department of Microbiology, Molecular Genetics, and Immunology, 2000 Hixon Hall, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, Kansas 66160
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3
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Lim HJ, Wubben JM, Garcia CP, Cruz-Gomez S, Deng J, Mak JY, Hachani A, Anderson RJ, Painter GF, Goyette J, Amarasinghe SL, Ritchie ME, Roquilly A, Fairlie DP, Gaus K, Rossjohn J, Villadangos JA, McWilliam HE. A specialized tyrosine-based endocytosis signal in MR1 controls antigen presentation to MAIT cells. J Cell Biol 2022; 221:213489. [PMID: 36129434 PMCID: PMC9499830 DOI: 10.1083/jcb.202110125] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 06/23/2022] [Accepted: 09/01/2022] [Indexed: 12/13/2022] Open
Abstract
MR1 is a highly conserved microbial immune-detection system in mammals. It captures vitamin B-related metabolite antigens from diverse microbes and presents them at the cell surface to stimulate MR1-restricted lymphocytes including mucosal-associated invariant T (MAIT) cells. MR1 presentation and MAIT cell recognition mediate homeostasis through host defense and tissue repair. The cellular mechanisms regulating MR1 cell surface expression are critical to its function and MAIT cell recognition, yet they are poorly defined. Here, we report that human MR1 is equipped with a tyrosine-based motif in its cytoplasmic domain that mediates low affinity binding with the endocytic adaptor protein 2 (AP2) complex. This interaction controls the kinetics of MR1 internalization from the cell surface and minimizes recycling. We propose MR1 uses AP2 endocytosis to define the duration of antigen presentation to MAIT cells and the detection of a microbial metabolic signature by the immune system.
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Affiliation(s)
- Hui Jing Lim
- Department of Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute of Infection and Immunity, Melbourne, Victoria, Australia
| | - Jacinta M. Wubben
- Infection and Immunity Program and The Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute Monash University, Clayton, Victoria, Australia
| | - Cristian Pinero Garcia
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, The University of New South Wales, Sydney, Australia
| | - Sebastian Cruz-Gomez
- Department of Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute of Infection and Immunity, Melbourne, Victoria, Australia
| | - Jieru Deng
- Department of Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute of Infection and Immunity, Melbourne, Victoria, Australia
| | - Jeffrey Y.W. Mak
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Abderrahman Hachani
- Department of Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute of Infection and Immunity, Melbourne, Victoria, Australia
| | - Regan J. Anderson
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Gavin F. Painter
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Jesse Goyette
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, The University of New South Wales, Sydney, Australia
| | - Shanika L. Amarasinghe
- Epigenetics and Development Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Matthew E. Ritchie
- Epigenetics and Development Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Antoine Roquilly
- Department of Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute of Infection and Immunity, Melbourne, Victoria, Australia
- Nantes Université, CHU Nantes, INSERM, Center for Research in Transplantation and Translational Immunology, UMR 1064; F-44000, Nantes, France
| | - David P. Fairlie
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, The University of New South Wales, Sydney, Australia
| | - Jamie Rossjohn
- Infection and Immunity Program and The Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute Monash University, Clayton, Victoria, Australia
- Institute of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff, UK
| | - Jose A. Villadangos
- Department of Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute of Infection and Immunity, Melbourne, Victoria, Australia
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
- Jose A. Villadangos:
| | - Hamish E.G. McWilliam
- Department of Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute of Infection and Immunity, Melbourne, Victoria, Australia
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
- Correspondence to Hamish E.G. McWilliam:
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DeGroot ACM, Gollapudi S, Zhao C, LaMonica MF, Stachowiak JC. Weakly Internalized Receptors Use Coated Vesicle Heterogeneity to Evade Competition during Endocytosis. Biochemistry 2021; 60:2195-2205. [PMID: 34170686 PMCID: PMC8483609 DOI: 10.1021/acs.biochem.1c00268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The uptake of receptors by clathrin-mediated endocytosis underlies signaling, nutrient import, and recycling of transmembrane proteins and lipids. In the complex, crowded environment of the plasma membrane, receptors are internalized when they bind to components of the clathrin coat, such as the major adaptor protein, AP2. Receptors with higher affinity for AP2 are known to be more strongly internalized compared to receptors with lower affinity. However, it remains unclear how receptors with different affinities compete for space within crowded endocytic structures. To address this question, we constructed receptors with varying affinities for AP2 and allowed them to compete against one another during internalization. As expected, the internalization of a receptor with high affinity for AP2 was reduced when it was coexpressed with a competing receptor of similar affinity. However, receptors of low affinity for AP2 were surprisingly difficult to displace from endocytic structures, even when expressed alongside receptors with much higher affinity. To understand how these low-affinity receptors are protected from competition, we looked at AP2 heterogeneity across clathrin-coated structures. When we examined structures with lower-than-average AP2 content, we found that they were relatively enriched in cargo of low affinity for AP2 and depleted of cargo with high affinity. These findings suggest that the heterogeneity of adaptor protein content across the population of endocytic structures enables the internalization of diverse receptors. Given the critical role that internalization plays in signaling, this effect may help to prevent strongly internalized receptors from interfering with the cell's ability to process signals from weakly internalized receptors.
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Affiliation(s)
| | - Sadhana Gollapudi
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Chi Zhao
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Megan F. LaMonica
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Jeanne C. Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin
- Institute for Cellular and Molecular Biology, The University of Texas at Austin
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5
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Kliche J, Kuss H, Ali M, Ivarsson Y. Cytoplasmic short linear motifs in ACE2 and integrin β 3 link SARS-CoV-2 host cell receptors to mediators of endocytosis and autophagy. Sci Signal 2021; 14:14/665/eabf1117. [PMID: 33436498 PMCID: PMC7928716 DOI: 10.1126/scisignal.abf1117] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
SARS-CoV-2, the virus that causes COVID-19, enters cells through endocytosis upon binding to the cell surface receptor ACE2 and potentially others, including integrins. Using bioinformatics, Mészáros et al. predicted the presence of short amino acid sequences, called short linear motifs (SLiMs), in the cytoplasmic tails of ACE2 and various integrins that may engage the endocytic and autophagic machinery. Using affinity binding assays, Kliche et al. not only confirmed that many of these predicted SLiMs interacted with target peptides in various components of the endocytosis and autophagy machinery, but also found that these interactions were regulated by the phosphorylation of SLiM-adjacent amino acids. Together, these findings have identified a potential link between autophagy and integrin signaling and could lead to new ways to prevent viral infection. The spike protein of SARS-CoV-2 binds the angiotensin-converting enzyme 2 (ACE2) on the host cell surface and subsequently enters host cells through receptor-mediated endocytosis. Additional cell receptors may be directly or indirectly involved, including integrins. The cytoplasmic tails of ACE2 and integrins contain several predicted short linear motifs (SLiMs) that may facilitate internalization of the virus as well as its subsequent propagation through processes such as autophagy. Here, we measured the binding affinity of predicted interactions between SLiMs in the cytoplasmic tails of ACE2 and integrin β3 with proteins that mediate endocytic trafficking and autophagy. We validated that a class I PDZ-binding motif mediated binding of ACE2 to the scaffolding proteins SNX27, NHERF3, and SHANK, and that a binding site for the clathrin adaptor AP2 μ2 in ACE2 overlaps with a phospho-dependent binding site for the SH2 domains of Src family tyrosine kinases. Furthermore, we validated that an LC3-interacting region (LIR) in integrin β3 bound to the ATG8 domains of the autophagy receptors MAP1LC3 and GABARAP in a manner enhanced by LIR-adjacent phosphorylation. Our results provide molecular links between cell receptors and mediators of endocytosis and autophagy that may facilitate viral entry and propagation.
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Affiliation(s)
- Johanna Kliche
- Department of Chemistry, BMC, Uppsala University, Husargatan 3, 751 23 Uppsala, Sweden
| | - Hanna Kuss
- Department of Chemistry, BMC, Uppsala University, Husargatan 3, 751 23 Uppsala, Sweden.,WWU Münster, Institute for Evolution and Biodiversity, DE-48149 Münster, Germany
| | - Muhammad Ali
- Department of Chemistry, BMC, Uppsala University, Husargatan 3, 751 23 Uppsala, Sweden
| | - Ylva Ivarsson
- Department of Chemistry, BMC, Uppsala University, Husargatan 3, 751 23 Uppsala, Sweden.
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6
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Meyer SJ, Böser A, Korn MA, Koller C, Bertocci B, Reimann L, Warscheid B, Nitschke L. Cullin 3 Is Crucial for Pro-B Cell Proliferation, Interacts with CD22, and Controls CD22 Internalization on B Cells. THE JOURNAL OF IMMUNOLOGY 2020; 204:3360-3374. [DOI: 10.4049/jimmunol.1900925] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 04/03/2020] [Indexed: 12/15/2022]
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7
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Wu G, Cui X, Dai Z, He R, Li Y, Yu K, Bernards M, Chen X, Wang A. A plant RNA virus hijacks endocytic proteins to establish its infection in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:384-400. [PMID: 31562664 DOI: 10.1111/tpj.14549] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/11/2019] [Accepted: 09/16/2019] [Indexed: 06/10/2023]
Abstract
Endocytosis and endosomal trafficking play essential roles in diverse biological processes including responses to pathogen attack. It is well established that animal viruses enter host cells through receptor-mediated endocytosis for infection. However, the role of endocytosis in plant virus infection still largely remains unknown. Plant dynamin-related proteins 1 (DRP1) and 2 (DRP2) are the large, multidomain GTPases that participate together in endocytosis. Recently, we have discovered that DRP2 is co-opted by Turnip mosaic virus (TuMV) for infection in plants. We report here that DRP1 is also required for TuMV infection. We show that overexpression of DRP1 from Arabidopsis thaliana (AtDRP1A) promotes TuMV infection, and AtDRP1A interacts with several viral proteins including VPg and cylindrical inclusion (CI), which are the essential components of the virus replication complex (VRC). AtDRP1A colocalizes with the VRC in TuMV-infected cells. Transient expression of a dominant negative (DN) mutant of DRP1A disrupts DRP1-dependent endocytosis and supresses TuMV replication. As adaptor protein (AP) complexes mediate cargo selection for endocytosis, we further investigated the requirement of AP in TuMV infection. Our data suggest that the medium unit of the AP2 complex (AP2β) is responsible for recognizing the viral proteins as cargoes for endocytosis, and knockout of AP2β impairs intracellular endosomal trafficking of VPg and CI and inhibits TuMV replication. Collectively, our results demonstrate that DRP1 and AP2β are two proviral host factors of TuMV and shed light into the involvement of endocytosis and endosomal trafficking in plant virus infection.
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Affiliation(s)
- Guanwei Wu
- London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford St, London, Ontario, N5V 4T3, Canada
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing, Jiangsu, 210014, People's Republic of China
- Department of Biology, University of Western Ontario, 1151 Richmond ST, London, Ontario, N6A 5B7, Canada
| | - Xiaoyan Cui
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing, Jiangsu, 210014, People's Republic of China
| | - Zhaoji Dai
- London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford St, London, Ontario, N5V 4T3, Canada
- Department of Biology, University of Western Ontario, 1151 Richmond ST, London, Ontario, N6A 5B7, Canada
| | - Rongrong He
- London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford St, London, Ontario, N5V 4T3, Canada
- Department of Biology, University of Western Ontario, 1151 Richmond ST, London, Ontario, N6A 5B7, Canada
| | - Yinzi Li
- London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford St, London, Ontario, N5V 4T3, Canada
| | - Kangfu Yu
- Harrow Research and Development Centre, Agriculture and Agri-Food Canada, 2585 County Road 20, Harrow, Ontario, N0R 1G0, Canada
| | - Mark Bernards
- Department of Biology, University of Western Ontario, 1151 Richmond ST, London, Ontario, N6A 5B7, Canada
| | - Xin Chen
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing, Jiangsu, 210014, People's Republic of China
| | - Aiming Wang
- London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford St, London, Ontario, N5V 4T3, Canada
- Department of Biology, University of Western Ontario, 1151 Richmond ST, London, Ontario, N6A 5B7, Canada
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8
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Gulbranson DR, Crisman L, Lee M, Ouyang Y, Menasche BL, Demmitt BA, Wan C, Nomura T, Ye Y, Yu H, Shen J. AAGAB Controls AP2 Adaptor Assembly in Clathrin-Mediated Endocytosis. Dev Cell 2019; 50:436-446.e5. [PMID: 31353312 DOI: 10.1016/j.devcel.2019.06.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/29/2019] [Accepted: 06/20/2019] [Indexed: 12/26/2022]
Abstract
Multimeric adaptors are broadly involved in vesicle-mediated membrane trafficking. AP2 adaptor, in particular, plays a central role in clathrin-mediated endocytosis (CME) by recruiting cargo and clathrin to endocytic sites. It is generally thought that trafficking adaptors such as AP2 adaptor assemble spontaneously. In this work, however, we discovered that AP2 adaptor assembly is an ordered process controlled by alpha and gamma adaptin binding protein (AAGAB), an uncharacterized factor identified in our genome-wide genetic screen of CME. AAGAB guides the sequential association of AP2 subunits and stabilizes assembly intermediates. Without the assistance of AAGAB, AP2 subunits fail to form the adaptor complex, leading to their degradation. The function of AAGAB is abrogated by a mutation that causes punctate palmoplantar keratoderma type 1 (PPKP1), a human skin disease. Since other multimeric trafficking adaptors operate in an analogous manner to AP2 adaptor, their assembly likely involves a similar regulatory mechanism.
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Affiliation(s)
- Daniel R Gulbranson
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Lauren Crisman
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - MyeongSeon Lee
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Yan Ouyang
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Bridget L Menasche
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Brittany A Demmitt
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA; Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309, USA
| | - Chun Wan
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Toshifumi Nomura
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Yihong Ye
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Haijia Yu
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA; Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
| | - Jingshi Shen
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
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Smith SM, Baker M, Halebian M, Smith CJ. Weak Molecular Interactions in Clathrin-Mediated Endocytosis. Front Mol Biosci 2017; 4:72. [PMID: 29184887 PMCID: PMC5694535 DOI: 10.3389/fmolb.2017.00072] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 10/11/2017] [Indexed: 11/21/2022] Open
Abstract
Clathrin-mediated endocytosis is a process by which specific molecules are internalized from the cell periphery for delivery to early endosomes. The key stages in this step-wise process, from the starting point of cargo recognition, to the later stage of assembly of the clathrin coat, are dependent on weak interactions between a large network of proteins. This review discusses the structural and functional data that have improved our knowledge and understanding of the main weak molecular interactions implicated in clathrin-mediated endocytosis, with a particular focus on the two key proteins: AP2 and clathrin.
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Affiliation(s)
- Sarah M Smith
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Michael Baker
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Mary Halebian
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Corinne J Smith
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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10
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Apel AR, Hoban K, Chuartzman S, Tonikian R, Sidhu S, Schuldiner M, Wendland B, Prosser D. Syp1 regulates the clathrin-mediated and clathrin-independent endocytosis of multiple cargo proteins through a novel sorting motif. Mol Biol Cell 2017; 28:2434-2448. [PMID: 28701344 PMCID: PMC5576906 DOI: 10.1091/mbc.e15-10-0731] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 06/21/2017] [Accepted: 06/27/2017] [Indexed: 12/14/2022] Open
Abstract
Internalization of proteins from the plasma membrane (PM) allows for cell-surface composition regulation, signaling of network modulation, and nutrient uptake. Clathrin-mediated endocytosis (CME) is a major internalization route for PM proteins. During CME, endocytic adaptor proteins bind cargoes at the cell surface and link them to the PM and clathrin coat. Muniscins are a conserved family of endocytic adaptors, including Syp1 in budding yeast and its mammalian orthologue, FCHo1. These adaptors bind cargo via a C-terminal μ-homology domain (μHD); however, few cargoes exhibiting muniscin-dependent endocytosis have been identified, and the sorting sequence recognized by the µHD is unknown. To reveal Syp1 cargo-sorting motifs, we performed a phage display screen and used biochemical methods to demonstrate that the Syp1 µHD binds DxY motifs in the previously identified Syp1 cargo Mid2 and the v-SNARE Snc1. We also executed an unbiased visual screen, which identified the peptide transporter Ptr2 and the ammonium permease Mep3 as Syp1 cargoes containing DxY motifs. Finally, we determined that, in addition to regulating cargo entry through CME, Syp1 can promote internalization of Ptr2 through a recently identified clathrin-independent endocytic pathway that requires the Rho1 GTPase. These findings elucidate the mechanism of Syp1 cargo recognition and its role in trafficking.
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Affiliation(s)
| | - Kyle Hoban
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218
| | - Silvia Chuartzman
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Raffi Tonikian
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Sachdev Sidhu
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Beverly Wendland
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218
| | - Derek Prosser
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218
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11
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Lacruz RS, Habelitz S, Wright JT, Paine ML. DENTAL ENAMEL FORMATION AND IMPLICATIONS FOR ORAL HEALTH AND DISEASE. Physiol Rev 2017; 97:939-993. [PMID: 28468833 DOI: 10.1152/physrev.00030.2016] [Citation(s) in RCA: 223] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 12/16/2022] Open
Abstract
Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as weapons and/or tools as well as for food processing. Enamel development and mineralization is an intricate process tightly regulated by cells of the enamel organ called ameloblasts. These heavily polarized cells form a monolayer around the developing enamel tissue and move as a single forming front in specified directions as they lay down a proteinaceous matrix that serves as a template for crystal growth. Ameloblasts maintain intercellular connections creating a semi-permeable barrier that at one end (basal/proximal) receives nutrients and ions from blood vessels, and at the opposite end (secretory/apical/distal) forms extracellular crystals within specified pH conditions. In this unique environment, ameloblasts orchestrate crystal growth via multiple cellular activities including modulating the transport of minerals and ions, pH regulation, proteolysis, and endocytosis. In many vertebrates, the bulk of the enamel tissue volume is first formed and subsequently mineralized by these same cells as they retransform their morphology and function. Cell death by apoptosis and regression are the fates of many ameloblasts following enamel maturation, and what cells remain of the enamel organ are shed during tooth eruption, or are incorporated into the tooth's epithelial attachment to the oral gingiva. In this review, we examine key aspects of dental enamel formation, from its developmental genesis to the ever-increasing wealth of data on the mechanisms mediating ionic transport, as well as the clinical outcomes resulting from abnormal ameloblast function.
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Affiliation(s)
- Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - Stefan Habelitz
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - J Timothy Wright
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - Michael L Paine
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
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12
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Terragni B, Scalmani P, Franceschetti S, Cestèle S, Mantegazza M. Post-translational dysfunctions in channelopathies of the nervous system. Neuropharmacology 2017; 132:31-42. [PMID: 28571716 DOI: 10.1016/j.neuropharm.2017.05.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/12/2017] [Accepted: 05/26/2017] [Indexed: 12/23/2022]
Abstract
Channelopathies comprise various diseases caused by defects of ion channels. Modifications of their biophysical properties are common and have been widely studied. However, ion channels are heterogeneous multi-molecular complexes that are extensively modulated and undergo a maturation process comprising numerous steps of structural modifications and intracellular trafficking. Perturbations of these processes can give rise to aberrant channels that cause pathologies. Here we review channelopathies of the nervous system associated with dysfunctions at the post-translational level (folding, trafficking, degradation, subcellular localization, interactions with associated proteins and structural post-translational modifications). We briefly outline the physiology of ion channels' maturation and discuss examples of defective mechanisms, focusing in particular on voltage-gated sodium channels, which are implicated in numerous neurological disorders. We also shortly introduce possible strategies to develop therapeutic approaches that target these processes. This article is part of the Special Issue entitled 'Channelopathies.'
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Affiliation(s)
- Benedetta Terragni
- U.O. Neurophysiology and Diagnostic Epileptology, Foundation IRCCS Neurological Institute C. Besta, 20133 Milan, Italy
| | - Paolo Scalmani
- U.O. Neurophysiology and Diagnostic Epileptology, Foundation IRCCS Neurological Institute C. Besta, 20133 Milan, Italy
| | - Silvana Franceschetti
- U.O. Neurophysiology and Diagnostic Epileptology, Foundation IRCCS Neurological Institute C. Besta, 20133 Milan, Italy
| | - Sandrine Cestèle
- Institute of Molecular and Cellular Pharmacology (IPMC), CNRS UMR7275, 06560, Valbonne-Sophia Antipolis, France; University Côte d'Azur (UCA), 06560, Valbonne-Sophia Antipolis, France
| | - Massimo Mantegazza
- Institute of Molecular and Cellular Pharmacology (IPMC), CNRS UMR7275, 06560, Valbonne-Sophia Antipolis, France; University Côte d'Azur (UCA), 06560, Valbonne-Sophia Antipolis, France.
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13
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Gorvin CM, Rogers A, Stewart M, Paudyal A, Hough TA, Teboul L, Wells S, Brown SD, Cox RD, Thakker RV. N-ethyl-N-nitrosourea-Induced Adaptor Protein 2 Sigma Subunit 1 ( Ap2s1) Mutations Establish Ap2s1 Loss-of-Function Mice. JBMR Plus 2017; 1:3-15. [PMID: 29479578 PMCID: PMC5824975 DOI: 10.1002/jbm4.10001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The adaptor protein‐2 sigma subunit (AP2σ), encoded by AP2S1, forms a heterotetrameric complex, with AP2α, AP2β, and AP2μ subunits, that is pivotal for clathrin‐mediated endocytosis, and AP2σ loss‐of‐function mutations impair internalization of the calcium‐sensing receptor (CaSR), a G‐protein–coupled receptor, and cause familial hypocalciuric hypercalcemia type‐3 (FHH3). Mice with AP2σ mutations that would facilitate investigations of the in vivo role of AP2σ, are not available, and we therefore embarked on establishing such mice. We screened >10,000 mice treated with the mutagen N‐ethyl‐N‐nitrosourea (ENU) for Ap2s1 mutations and identified 5 Ap2s1 variants, comprising 2 missense (Tyr20Asn and Ile123Asn) and 3 intronic base substitutions, one of which altered the invariant donor splice site dinucleotide gt to gc. Three‐dimensional modeling and cellular expression of the missense Ap2s1 variants did not reveal them to alter AP2σ structure or CaSR‐mediated signaling, but investigation of the donor splice site variant revealed it to result in an in‐frame deletion of 17 evolutionarily conserved amino acids (del17) that formed part of the AP2σ α1‐helix, α1‐β3 loop, and β3 strand. Heterozygous mutant mice (Ap2s1+/del17) were therefore established, and these had AP2σ haplosufficiency but were viable with normal appearance and growth. Ap2s1+/del17 mice, when compared with Ap2s1+/+ mice, also had normal plasma concentrations of calcium, phosphate, magnesium, creatinine, urea, sodium, potassium, and alkaline phosphatase activity; normal urinary fractional excretion of calcium, phosphate, sodium, and potassium; and normal plasma parathyroid hormone (PTH) and 1,25‐dihydroxyvitamin D (1,25(OH)2) concentrations. However, homozygous Ap2s1del17/del17 mice were non‐viable and died between embryonic days 3.5 and 9.5 (E3.5–9.5), thereby indicating that AP2σ likely has important roles at the embryonic patterning stages and organogenesis of the heart, thyroid, liver, gut, lungs, pancreas, and neural systems. Thus, our studies have established a mutant mouse model that is haplosufficient for AP2σ. © 2017 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.
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Affiliation(s)
- Caroline M Gorvin
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology, and Metabolism (OCDEM), Churchill Hospital, Oxford, UK
| | - Angela Rogers
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology, and Metabolism (OCDEM), Churchill Hospital, Oxford, UK
| | - Michelle Stewart
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Anju Paudyal
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Tertius A Hough
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Lydia Teboul
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Sara Wells
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Steve Dm Brown
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Roger D Cox
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology, and Metabolism (OCDEM), Churchill Hospital, Oxford, UK
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Brigidi GS, Santyr B, Shimell J, Jovellar B, Bamji SX. Activity-regulated trafficking of the palmitoyl-acyl transferase DHHC5. Nat Commun 2015; 6:8200. [PMID: 26334723 PMCID: PMC4569850 DOI: 10.1038/ncomms9200] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 07/28/2015] [Indexed: 12/16/2022] Open
Abstract
Synaptic plasticity is mediated by the dynamic localization of proteins to and from synapses. This is controlled, in part, through activity-induced palmitoylation of synaptic proteins. Here we report that the ability of the palmitoyl-acyl transferase, DHHC5, to palmitoylate substrates in an activity-dependent manner is dependent on changes in its subcellular localization. Under basal conditions, DHHC5 is bound to PSD-95 and Fyn kinase, and is stabilized at the synaptic membrane through Fyn-mediated phosphorylation of a tyrosine residue within the endocytic motif of DHHC5. In contrast, DHHC5's substrate, δ-catenin, is highly localized to dendritic shafts, resulting in the segregation of the enzyme/substrate pair. Neuronal activity disrupts DHHC5/PSD-95/Fyn kinase complexes, enhancing DHHC5 endocytosis, its translocation to dendritic shafts and its association with δ-catenin. Following DHHC5-mediated palmitoylation of δ-catenin, DHHC5 and δ-catenin are trafficked together back into spines where δ-catenin increases cadherin stabilization and recruitment of AMPA receptors to the synaptic membrane. Synaptic plasticity is mediated by the dynamic localization of proteins at synapses, which is partly controlled via palmitoylation of synaptic proteins. Here, the authors show how neuronal activity regulates the palmitoylation reaction through the translocation of the palmitoyl-acyl transferase DHHC5.
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Affiliation(s)
- G Stefano Brigidi
- Department of Cellular and Physiological Sciences, and the Djavad Mowafaghian Center for Brain Health, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T-1Z3
| | - Brendan Santyr
- Department of Cellular and Physiological Sciences, and the Djavad Mowafaghian Center for Brain Health, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T-1Z3
| | - Jordan Shimell
- Department of Cellular and Physiological Sciences, and the Djavad Mowafaghian Center for Brain Health, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T-1Z3
| | - Blair Jovellar
- Department of Cellular and Physiological Sciences, and the Djavad Mowafaghian Center for Brain Health, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T-1Z3
| | - Shernaz X Bamji
- Department of Cellular and Physiological Sciences, and the Djavad Mowafaghian Center for Brain Health, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T-1Z3
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15
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Busch DJ, Houser JR, Hayden CC, Sherman MB, Lafer EM, Stachowiak JC. Intrinsically disordered proteins drive membrane curvature. Nat Commun 2015. [PMID: 26204806 PMCID: PMC4515776 DOI: 10.1038/ncomms8875] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Assembly of highly curved membrane structures is essential to cellular physiology. The prevailing view has been that proteins with curvature-promoting structural motifs, such as wedge-like amphipathic helices and crescent-shaped BAR domains, are required for bending membranes. Here we report that intrinsically disordered domains of the endocytic adaptor proteins, Epsin1 and AP180 are highly potent drivers of membrane curvature. This result is unexpected since intrinsically disordered domains lack a well-defined three-dimensional structure. However, in vitro measurements of membrane curvature and protein diffusivity demonstrate that the large hydrodynamic radii of these domains generate steric pressure that drives membrane bending. When disordered adaptor domains are expressed as transmembrane cargo in mammalian cells, they are excluded from clathrin-coated pits. We propose that a balance of steric pressure on the two surfaces of the membrane drives this exclusion. These results provide quantitative evidence for the influence of steric pressure on the content and assembly of curved cellular membrane structures. Proteins that bend membranes often contain curvature-promoting structural motifs such as wedges or crescent-shaped domains. Busch et al. report that intrinsically disordered domains can also drive membrane curvature and provide evidence that steric pressure driven by protein crowding mediates this effect.
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Affiliation(s)
- David J Busch
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W Dean Keeton, Austin, Texas 78712, USA
| | - Justin R Houser
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W Dean Keeton, Austin, Texas 78712, USA
| | - Carl C Hayden
- 1] Department of Biomedical Engineering, The University of Texas at Austin, 107 W Dean Keeton, Austin, Texas 78712, USA [2] Sandia National Laboratories, 7011 East Avenue, Livermore, California 94550, USA
| | - Michael B Sherman
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 1.224 Medical Research Building, Galveston, Texas 77555, USA
| | - Eileen M Lafer
- Department of Biochemistry and Center for Biomedical Neuroscience, The University of Texas Health Science Center at San Antonio, UTHSCSA Biochemistry 415B, 7703 Floyd Curl Drive, San Antonio, Texas 78229, USA
| | - Jeanne C Stachowiak
- 1] Department of Biomedical Engineering, The University of Texas at Austin, 107 W Dean Keeton, Austin, Texas 78712, USA [2] Institute for Cellular and Molecular Biology, The University of Texas at Austin, 107 W Dean, Keeton,Texas 78712, USA
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16
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Augusto DG, O’Connor GM, Lobo-Alves SC, Bass S, Martin MP, Carrington M, McVicar DW, Petzl-Erler ML. Pemphigus is associated with KIR3DL2 expression levels and provides evidence that KIR3DL2 may bind HLA-A3 and A11 in vivo. Eur J Immunol 2015; 45:2052-60. [PMID: 25867094 PMCID: PMC4530613 DOI: 10.1002/eji.201445324] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 03/03/2015] [Accepted: 04/09/2015] [Indexed: 12/18/2022]
Abstract
Although HLA-A3 and A11 have been reported to be ligands for KIR3DL2, evidence for any in vivo relevance of this interaction is still missing. To explore the functional importance of KIR3DL2 allelic variation, we analyzed the autoimmune disease pemphigus foliaceus, previously associated (lower risk) with activating KIR genes. KIR3DL2*001 was increased in patients (odds ratio (OR) = 2.04; p = 0.007). The risk was higher for the presence of both KIR3DL2*001 and HLA-A3 or A11 (OR = 3.76, p = 0.013), providing the first evidence that HLA-A3 and A11 may interact with KIR3DL2 in vivo. The nonsynonymous single nucleotide polymorphism 1190T (rs3745902) was associated with protection (OR = 0.52, p = 0.018). This SNP results in a threonine-to-methionine substitution. Individuals who have methionine in this position exhibit a lower percentage of KIR3DL2-positive natural killer (NK) cells and also lower intensity of KIR3DL2 on expressing natural killer cells; additionally, we show that the expression of KIR3DL2 is independent of other killer cell immunoglobulin-like receptors. Pemphigus foliaceus is a very unique complex disease strongly associated with immune-related genes. It is the only autoimmune disease known to be endemic, showing a strong correlation with environmental factors. Our data demonstrate that this relatively unknown autoimmune disease may facilitate understanding of the molecular mechanisms of KIR3DL2 ligand recognition.
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Affiliation(s)
- Danillo G. Augusto
- Departamento de Genética, Universidade Federal do Paraná, Curitiba, PR, 81531-980, Brazil
- Ragon Institute of MGH, MIT and Harvard, Boston, MA, 02139, USA
- Leidos Biomedical Research, Cancer and Inflammation Program, Laboratory for Experimental Immunology, Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Geraldine M. O’Connor
- Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Sara C. Lobo-Alves
- Departamento de Genética, Universidade Federal do Paraná, Curitiba, PR, 81531-980, Brazil
| | - Sara Bass
- Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Maureen P. Martin
- Leidos Biomedical Research, Cancer and Inflammation Program, Laboratory for Experimental Immunology, Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Mary Carrington
- Ragon Institute of MGH, MIT and Harvard, Boston, MA, 02139, USA
- Leidos Biomedical Research, Cancer and Inflammation Program, Laboratory for Experimental Immunology, Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Daniel W. McVicar
- Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
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AP-2-associated protein kinase 1 and cyclin G-associated kinase regulate hepatitis C virus entry and are potential drug targets. J Virol 2015; 89:4387-404. [PMID: 25653444 DOI: 10.1128/jvi.02705-14] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Hepatitis C virus (HCV) enters its target cell via clathrin-mediated endocytosis. AP-2-associated protein kinase 1 (AAK1) and cyclin G-associated kinase (GAK) are host kinases that regulate clathrin adaptor protein (AP)-mediated trafficking in the endocytic and secretory pathways. We previously reported that AAK1 and GAK regulate HCV assembly by stimulating binding of the μ subunit of AP-2, AP2M1, to HCV core protein. We also discovered that AAK1 and GAK inhibitors, including the approved anticancer drugs sunitinib and erlotinib, could block HCV assembly. Here, we hypothesized that AAK1 and GAK regulate HCV entry independently of their effect on HCV assembly. Indeed, silencing AAK1 and GAK expression inhibited entry of pseudoparticles and cell culture grown-HCV and internalization of Dil-labeled HCV particles with no effect on HCV attachment or RNA replication. AAK1 or GAK depletion impaired epidermal growth factor (EGF)-mediated enhanced HCV entry and endocytosis of EGF receptor (EGFR), an HCV entry cofactor and erlotinib's cancer target. Moreover, either RNA interference-mediated depletion of AP2M1 or NUMB, each a substrate of AAK1 and/or GAK, or overexpression of either an AP2M1 or NUMB phosphorylation site mutant inhibited HCV entry. Last, in addition to affecting assembly, sunitinib and erlotinib inhibited HCV entry at a postbinding step, their combination was synergistic, and their antiviral effect was reversed by either AAK1 or GAK overexpression. Together, these results validate AAK1 and GAK as critical regulators of HCV entry that function in part by activating EGFR, AP2M1, and NUMB and as the molecular targets underlying the antiviral effect of sunitinib and erlotinib (in addition to EGFR), respectively. IMPORTANCE Understanding the host pathways hijacked by HCV is critical for developing host-centered anti-HCV approaches. Entry represents a potential target for antiviral strategies; however, no FDA-approved HCV entry inhibitors are currently available. We reported that two host kinases, AAK1 and GAK, regulate HCV assembly. Here, we provide evidence that AAK1 and GAK regulate HCV entry independently of their role in HCV assembly and define the mechanisms underlying AAK1- and GAK-mediated HCV entry. By regulating temporally distinct steps in the HCV life cycle, AAK1 and GAK represent "master regulators" of HCV infection and potential targets for antiviral strategies. Indeed, approved anticancer drugs that potently inhibit AAK1 or GAK inhibit HCV entry in addition to assembly. These results contribute to an understanding of the mechanisms of HCV entry and reveal attractive host targets for antiviral strategies as well as approved candidate inhibitors of these targets, with potential implications for other viruses that hijack clathrin-mediated pathways.
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Cocucci E, Gaudin R, Kirchhausen T. Dynamin recruitment and membrane scission at the neck of a clathrin-coated pit. Mol Biol Cell 2014; 25:3595-609. [PMID: 25232009 PMCID: PMC4230619 DOI: 10.1091/mbc.e14-07-1240] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Dynamin2 dimers are the preferred assembly units recruited to coated pits. About 26 dynamins (one helical turn of a dynamin collar) are enough for release of most coated vesicles. A circumferential twist–propagating model is proposed that requires that one complete turn of the helix reach a state in which one or more pairs of GTPase domains interact. Dynamin, the GTPase required for clathrin-mediated endocytosis, is recruited to clathrin-coated pits in two sequential phases. The first is associated with coated pit maturation; the second, with fission of the membrane neck of a coated pit. Using gene-edited cells that express dynamin2-EGFP instead of dynamin2 and live-cell TIRF imaging with single-molecule EGFP sensitivity and high temporal resolution, we detected the arrival of dynamin at coated pits and defined dynamin dimers as the preferred assembly unit. We also used live-cell spinning-disk confocal microscopy calibrated by single-molecule EGFP detection to determine the number of dynamins recruited to the coated pits. A large fraction of budding coated pits recruit between 26 and 40 dynamins (between 1 and 1.5 helical turns of a dynamin collar) during the recruitment phase associated with neck fission; 26 are enough for coated vesicle release in cells partially depleted of dynamin by RNA interference. We discuss how these results restrict models for the mechanism of dynamin-mediated membrane scission.
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Affiliation(s)
- Emanuele Cocucci
- Department of Cell Biology, Harvard Medical School, and Cellular and Molecular Medicine Program, Boston Children's Hospital, Boston, MA 02115 Department of Pediatrics, Harvard Medical School, Boston, MA 02115
| | - Raphaël Gaudin
- Department of Cell Biology, Harvard Medical School, and Cellular and Molecular Medicine Program, Boston Children's Hospital, Boston, MA 02115
| | - Tom Kirchhausen
- Department of Cell Biology, Harvard Medical School, and Cellular and Molecular Medicine Program, Boston Children's Hospital, Boston, MA 02115 Department of Pediatrics, Harvard Medical School, Boston, MA 02115
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Kabeiseman EJ, Cichos KH, Moore ER. The eukaryotic signal sequence, YGRL, targets the chlamydial inclusion. Front Cell Infect Microbiol 2014; 4:129. [PMID: 25309881 PMCID: PMC4161167 DOI: 10.3389/fcimb.2014.00129] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 08/28/2014] [Indexed: 11/13/2022] Open
Abstract
Understanding how host proteins are targeted to pathogen-specified organelles, like the chlamydial inclusion, is fundamentally important to understanding the biogenesis of these unique subcellular compartments and how they maintain autonomy within the cell. Syntaxin 6, which localizes to the chlamydial inclusion, contains an YGRL signal sequence. The YGRL functions to return syntaxin 6 to the trans-Golgi from the plasma membrane, and deletion of the YGRL signal sequence from syntaxin 6 also prevents the protein from localizing to the chlamydial inclusion. YGRL is one of three YXXL (YGRL, YQRL, and YKGL) signal sequences which target proteins to the trans-Golgi. We designed various constructs of eukaryotic proteins to test the specificity and propensity of YXXL sequences to target the inclusion. The YGRL signal sequence redirects proteins (e.g., Tgn38, furin, syntaxin 4) that normally do not localize to the chlamydial inclusion. Further, the requirement of the YGRL signal sequence for syntaxin 6 localization to inclusions formed by different species of Chlamydia is conserved. These data indicate that there is an inherent property of the chlamydial inclusion, which allows it to recognize the YGRL signal sequence. To examine whether this "inherent property" was protein or lipid in nature, we asked if deletion of the YGRL signal sequence from syntaxin 6 altered the ability of the protein to interact with proteins or lipids. Deletion or alteration of the YGRL from syntaxin 6 does not appreciably impact syntaxin 6-protein interactions, but does decrease syntaxin 6-lipid interactions. Intriguingly, data also demonstrate that YKGL or YQRL can successfully substitute for YGRL in localization of syntaxin 6 to the chlamydial inclusion. Importantly and for the first time, we are establishing that a eukaryotic signal sequence targets the chlamydial inclusion.
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Affiliation(s)
| | | | - Elizabeth R. Moore
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South DakotaVermillion, SD, USA
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20
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Umemoto EY, Speck M, Shimoda LMN, Kahue K, Sung C, Stokes AJ, Turner H. Single-walled carbon nanotube exposure induces membrane rearrangement and suppression of receptor-mediated signalling pathways in model mast cells. Toxicol Lett 2014; 229:198-209. [PMID: 24910985 DOI: 10.1016/j.toxlet.2014.06.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 06/04/2014] [Accepted: 06/05/2014] [Indexed: 01/17/2023]
Abstract
Carbon nanotubes (CNT) are environmental challenges to the respiratory and gastrointestinal mucosa, and to the dermal immune system. Mast cells (MC) are pro-inflammatory immunocytes that reside at these interfaces with the environment. Mast cells are sources of pro-inflammatory mediators (histamine, serotonin, matrix-active proteases, eicosanoids, prostanoids, cytokines and chemokines), which are released in a calcium-dependent manner following immunological challenge or physico-chemical stimulation. Since C-60 fullerenes, which share geometry with CNT, are suppressive of mast cell-driven inflammatory responses, we explored the effects of unmodified SWCNT aggregates on mast cell signaling pathways, phenotype and pro-inflammatory function. We noted SWCNT suppression of antigen-induced signalling pathways and pro-inflammatory degranulation responses. Mast cells recognize unmodified SWCNT by remodeling the plasma membrane, disaggregating the cortical actin cytoskeleton and relocalizing clathrin. Clathrin was also identified as a component of an affinity-purified 'interactome' isolated from MC using an SWCNT affinity matrix for mast cell lysates. Together, these data are consistent with the ability of SWCNT to suppress mast cell pro-inflammatory function via a novel recognition mechanism.
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Affiliation(s)
- Eric Y Umemoto
- Laboratory of Immunology and Signal Transduction, Division of Natural Sciences and Mathematics, Chaminade University, Honolulu, HI, United States
| | - Mark Speck
- Laboratory of Immunology and Signal Transduction, Division of Natural Sciences and Mathematics, Chaminade University, Honolulu, HI, United States
| | - Lori M N Shimoda
- Laboratory of Immunology and Signal Transduction, Division of Natural Sciences and Mathematics, Chaminade University, Honolulu, HI, United States
| | - Kara Kahue
- Laboratory of Immunology and Signal Transduction, Division of Natural Sciences and Mathematics, Chaminade University, Honolulu, HI, United States; Undergraduate Program in Computer Sciences, Division of Natural Sciences and Mathematics, Chaminade University, Honolulu, HI, United States
| | - Carl Sung
- Laboratory of Immunology and Signal Transduction, Division of Natural Sciences and Mathematics, Chaminade University, Honolulu, HI, United States
| | - Alexander J Stokes
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, United States
| | - Helen Turner
- Laboratory of Immunology and Signal Transduction, Division of Natural Sciences and Mathematics, Chaminade University, Honolulu, HI, United States; Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, United States.
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Chakraborty S, Umasankar PK, Preston GM, Khandelwal P, Apodaca G, Watkins SC, Traub LM. A phosphotyrosine switch for cargo sequestration at clathrin-coated buds. J Biol Chem 2014; 289:17497-514. [PMID: 24798335 DOI: 10.1074/jbc.m114.556589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The AP-2 clathrin adaptor complex oversees endocytic cargo selection in two parallel but independent manners. First, by physically engaging peptide-based endocytic sorting signals, a subset of clathrin-dependent transmembrane cargo is directly collected into assembling buds. Synchronously, by interacting with an assortment of clathrin-associated sorting proteins (CLASPs) that independently select different integral membrane cargo for inclusion within the incipient bud, AP-2 handles additional cargo capture indirectly. The distal platform subdomain of the AP-2 β2 subunit appendage is a privileged CLASP-binding surface that recognizes a cognate, short α-helical interaction motif. This signal, found in the CLASPs β-arrestin and the autosomal recessive hypercholesterolemia (ARH) protein, docks into an elongated groove on the β2 appendage platform. Tyr-888 is a critical constituent of this spatially confined β2 appendage contact interface and is phosphorylated in numerous high-throughput proteomic studies. We find that a phosphomimetic Y888E substitution does not interfere with incorporation of expressed β2-YFP subunit into AP-2 or alter AP-2 deposition at surface clathrin-coated structures. The Y888E mutation does not affect interactions involving the sandwich subdomain of the β2 appendage, indicating that the mutated appendage is folded and operational. However, the Y888E, but not Y888F, switch selectively uncouples interactions with ARH and β-arrestin. Phyogenetic conservation of Tyr-888 suggests that this residue can reversibly control occupancy of the β2 platform-binding site and, hence, cargo sorting.
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Affiliation(s)
| | | | | | - Puneet Khandelwal
- the Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Gerard Apodaca
- the Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
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22
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Uwada J, Yoshiki H, Masuoka T, Nishio M, Muramatsu I. Intracellular localization of M1 muscarinic acetylcholine receptor through clathrin-dependent constitutive internalization via a C-terminal tryptophan-based motif. J Cell Sci 2014; 127:3131-40. [DOI: 10.1242/jcs.148478] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The M1 muscarinic acetylcholine receptor (M1-mAChR) is a G-protein-coupled membrane receptor that is activated by extracellular cholinergic stimuli. Recent investigations have revealed the intracellular localization of M1-mAChRs. In this study, we observed constitutive internalization of M1-mAChRs in mouse neuroblastoma N1E-115 cells without agonist stimulation. Constitutive internalization depends on dynamin, clathrin, and the adaptor protein-2 (AP-2) complex. A WXXI motif in the M1-mAChR C-terminus is essential for its constitutive internalization, since alanine mutations of W442 or I445 abolished constitutive internalization. This WXXI motif resembles YXXΦ, which is the canonical binding motif for the μ2 subunit of the AP-2 complex. The M1-mAChR C-terminal WXXI motif interacted with AP-2 μ2. W442A and I445A mutants of the M1-mAChR C-terminal sequence lost AP-2 μ2 binding activity, while the W442Y mutant bound more effectively than wild-type. Consistent with these results, W442A and I445A M1-mAChR mutants selectively localized to the cell surface. Conversely, the W442Y receptor mutant was found only at intracellular sites. Our data indicate that the cellular distribution of M1-mAChRs is governed by the C-terminal tryptophan-based motif that mediates constitutive internalization.
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23
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Perez-Reyes E, Lee JH. Ins and outs of T-channel structure function. Pflugers Arch 2013; 466:627-33. [PMID: 24337909 DOI: 10.1007/s00424-013-1419-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 12/03/2013] [Indexed: 02/07/2023]
Abstract
We review the ins and outs of T-channel structure, focusing on the extracellular high-affinity metal-binding site and intracellular loops. The high-affinity metal-binding site was localized to repeat I of Cav3.2. Interestingly, a similar binding site was found in the high voltage-activated Cav2.3 channel where it controls the channels' voltage dependence. Histidine at position 191 has a particularly interesting role in the high-affinity binding site, and its modification plays an important role in channel regulation by pharmacological agents that alter redox reactions. The intracellular loop connecting repeats I and II plays two important roles in Cav3.2 properties: one, its gating; and two, its surface expression. These studies have also identified a highly conserved intracellular gating brake that is predicted to form a helix-loop-helix structure. We conclude that the gating brake establishes important contacts with the gating machinery, thereby stabilizing a closed state of T-channels. This interaction is disrupted by depolarization, allowing the S6 segments to open and allowing Ca(2+) ions to flow through. Studies in cultured hippocampal neurons provided novel insights into how mutations found in idiopathic generalized epilepsy patients increase seizure susceptibility by both altering T-current pacemaker currents and by activating Ca-activated transcription factors that regulate dendritic arborization. These studies reveal novel roles for T-channels to control cellular physiology.
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Affiliation(s)
- Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA,
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24
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Endocytosis: At the Crossroads of Pattern Recognition Immune Receptors and Pathogen Effectors. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/978-3-642-41787-0_9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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25
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Eckle VS, Shcheglovitov A, Vitko I, Dey D, Yap CC, Winckler B, Perez-Reyes E. Mechanisms by which a CACNA1H mutation in epilepsy patients increases seizure susceptibility. J Physiol 2013; 592:795-809. [PMID: 24277868 DOI: 10.1113/jphysiol.2013.264176] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
T-type calcium channels play essential roles in regulating neuronal excitability and network oscillations in the brain. Mutations in the gene encoding Cav3.2 T-type Ca(2+) channels, CACNA1H, have been found in association with various forms of idiopathic generalized epilepsy. We and others have found that these mutations may influence neuronal excitability either by altering the biophysical properties of the channels or by increasing their surface expression. The goals of the present study were to investigate the excitability of neurons expressing Cav3.2 with the epilepsy mutation, C456S, and to elucidate the mechanisms by which it influences neuronal properties. We found that expression of the recombinant C456S channels substantially increased the excitability of cultured neurons by increasing the spontaneous firing rate and reducing the threshold for rebound burst firing. Additionally, we found that molecular determinants in the I-II loop (the region in which most childhood absence epilepsy-associated mutations are found) substantially increase the surface expression of T-channels but do not alter the relative distribution of channels into dendrites of cultured hippocampal neurons. Finally, we discovered that expression of C456S channels promoted dendritic growth and arborization. These effects were reversed to normal by either the absence epilepsy drug ethosuximide or a novel T-channel blocker, TTA-P2. As Ca(2+)-regulated transcription factors also increase dendritic development, we tested a transactivator trap assay and found that the C456S variant can induce changes in gene transcription. Taken together, our findings suggest that gain-of-function mutations in Cav3.2 T-type Ca(2+) channels increase seizure susceptibility by directly altering neuronal electrical properties and indirectly by changing gene expression.
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Affiliation(s)
- Veit-Simon Eckle
- Jordan Hall 800735, 1340 Jefferson Park Avenue, Charlottesville, VA 22908, USA.
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26
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Structural basis for recruitment and activation of the AP-1 clathrin adaptor complex by Arf1. Cell 2013; 152:755-67. [PMID: 23415225 DOI: 10.1016/j.cell.2012.12.042] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 10/16/2012] [Accepted: 12/18/2012] [Indexed: 11/23/2022]
Abstract
AP-1 is a clathrin adaptor complex that sorts cargo between the trans-Golgi network and endosomes. AP-1 recruitment to these compartments requires Arf1-GTP. The crystal structure of the tetrameric core of AP-1 in complex with Arf1-GTP, together with biochemical analyses, shows that Arf1 activates cargo binding by unlocking AP-1. Unlocking is driven by two molecules of Arf1 that bridge two copies of AP-1 at two interaction sites. The GTP-dependent switch I and II regions of Arf1 bind to the N terminus of the β1 subunit of one AP-1 complex, while the back side of Arf1 binds to the central part of the γ subunit trunk of a second AP-1 complex. A third Arf1 interaction site near the N terminus of the γ subunit is important for recruitment, but not activation. These observations lead to a model for the recruitment and activation of AP-1 by Arf1.
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27
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Rosnoblet C, Legrand D, Demaegd D, Hacine-Gherbi H, de Bettignies G, Bammens R, Borrego C, Duvet S, Morsomme P, Matthijs G, Foulquier F. Impact of disease-causing mutations on TMEM165 subcellular localization, a recently identified protein involved in CDG-II. Hum Mol Genet 2013; 22:2914-28. [PMID: 23575229 DOI: 10.1093/hmg/ddt146] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
TMEM165 has recently been identified as a novel protein involved in CDG-II. TMEM165 has no biological function described so far. Different mutations were recently found in patients with Golgi glycosylation defects and harboring a peculiar skeletal phenotype. In this study, we examined the effect of naturally occurring mutations on the intracellular localization of TMEM165 and their abilities to complement the TMEM165-deficient yeast, gdt1▵. Wild-type TMEM165 was present within Golgi compartment, plasma membrane and late endosomes/lysosomes, whereas mutated TMEM165 were found differentially localized according to the mutations. We demonstrated that, in the yeast functional assay with TMEM165 ortholog Gdt1, the homozygous point mutation correlating with a mild phenotype restores the yeast functional assay, whereas the truncated mutation, associated with severe disease, failed to restore Gdt1 function. These studies highly suggest that these clinically relevant point mutations do not affect the protein function but critically changes the subcellular protein localization. Moreover, the data point to a critical role of the YNRL motif in TMEM165 subcellular localization.
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Affiliation(s)
- Claire Rosnoblet
- CNRS-UMR 8576, Structural and Functional Glycobiology Unit, IFR 147, University of Lille 1, 59655 Villeneuve d’Ascq, France
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28
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Lacruz RS, Brookes SJ, Wen X, Jimenez JM, Vikman S, Hu P, White SN, Lyngstadaas SP, Okamoto CT, Smith CE, Paine ML. Adaptor protein complex 2-mediated, clathrin-dependent endocytosis, and related gene activities, are a prominent feature during maturation stage amelogenesis. J Bone Miner Res 2013; 28:672-87. [PMID: 23044750 PMCID: PMC3562759 DOI: 10.1002/jbmr.1779] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 09/14/2012] [Accepted: 09/18/2012] [Indexed: 12/14/2022]
Abstract
Molecular events defining enamel matrix removal during amelogenesis are poorly understood. Early reports have suggested that adaptor proteins (AP) participate in ameloblast-mediated endocytosis. Enamel formation involves the secretory and maturation stages, with an increase in resorptive function during the latter. Here, using real-time PCR, we show that the expression of clathrin and adaptor protein subunits are upregulated in maturation stage rodent enamel organ cells. AP complex 2 (AP-2) is the most upregulated of the four distinct adaptor protein complexes. Immunolocalization confirms the presence of AP-2 and clathrin in ameloblasts, with strongest reactivity at the apical pole. These data suggest that the resorptive functions of enamel cells involve AP-2 mediated, clathrin-dependent endocytosis, thus implying the likelihood of specific membrane-bound receptor(s) of enamel matrix protein debris. The mRNA expression of other endocytosis-related gene products is also upregulated during maturation including: lysosomal-associated membrane protein 1 (Lamp1); cluster of differentiation 63 and 68 (Cd63 and Cd68); ATPase, H(+) transporting, lysosomal V0 subunit D2 (Atp6v0d2); ATPase, H(+) transporting, lysosomal V1 subunit B2 (Atp6v1b2); chloride channel, voltage-sensitive 7 (Clcn7); and cathepsin K (Ctsk). Immunohistologic data confirms the expression of a number of these proteins in maturation stage ameloblasts. The enamel of Cd63-null mice was also examined. Despite increased mRNA and protein expression in the enamel organ during maturation, the enamel of Cd63-null mice appeared normal. This may suggest inherent functional redundancies between Cd63 and related gene products, such as Lamp1 and Cd68. Ameloblast-like LS8 cells treated with the enamel matrix protein complex Emdogain showed upregulation of AP-2 and clathrin subunits, further supporting the existence of a membrane-bound receptor-regulated pathway for the endocytosis of enamel matrix proteins. These data together define an endocytotic pathway likely used by ameloblasts to remove the enamel matrix during enamel maturation.
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Affiliation(s)
- Rodrigo S Lacruz
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90605, USA
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29
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Mardones GA, Burgos PV, Lin Y, Kloer DP, Magadán JG, Hurley JH, Bonifacino JS. Structural basis for the recognition of tyrosine-based sorting signals by the μ3A subunit of the AP-3 adaptor complex. J Biol Chem 2013; 288:9563-71. [PMID: 23404500 DOI: 10.1074/jbc.m113.450775] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tyrosine-based signals fitting the YXXØ motif mediate sorting of transmembrane proteins to endosomes, lysosomes, the basolateral plasma membrane of polarized epithelial cells, and the somatodendritic domain of neurons through interactions with the homologous μ1, μ2, μ3, and μ4 subunits of the corresponding AP-1, AP-2, AP-3, and AP-4 complexes. Previous x-ray crystallographic analyses identified distinct binding sites for YXXØ signals on μ2 and μ4, which were located on opposite faces of the proteins. To elucidate the mode of recognition of YXXØ signals by other members of the μ family, we solved the crystal structure at 1.85 Å resolution of the C-terminal domain of the μ3 subunit of AP-3 (isoform A) in complex with a peptide encoding a YXXØ signal (SDYQRL) from the trans-Golgi network protein TGN38. The μ3A C-terminal domain consists of an immunoglobulin-like β-sandwich organized into two subdomains, A and B. The YXXØ signal binds in an extended conformation to a site on μ3A subdomain A, at a location similar to the YXXØ-binding site on μ2 but not μ4. The binding sites on μ3A and μ2 exhibit similarities and differences that account for the ability of both proteins to bind distinct sets of YXXØ signals. Biochemical analyses confirm the identification of the μ3A site and show that this protein binds YXXØ signals with 14-19 μm affinity. The surface electrostatic potential of μ3A is less basic than that of μ2, in part explaining the association of AP-3 with intracellular membranes having less acidic phosphoinositides.
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Affiliation(s)
- Gonzalo A Mardones
- Instituto de Fisiología, Facultad de Medicina, and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia 5110566, Chile
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30
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Kim I, Pan W, Jones SA, Zhang Y, Zhuang X, Wu D. Clathrin and AP2 are required for PtdIns(4,5)P2-mediated formation of LRP6 signalosomes. ACTA ACUST UNITED AC 2013; 200:419-28. [PMID: 23400998 PMCID: PMC3575536 DOI: 10.1083/jcb.201206096] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
PtdIns(4,5)P2 promotes the assembly of LRP6 signalosomes at the cell surface via the recruitment of AP2 and clathrin. Canonical Wnt signaling is initiated by the binding of Wnt proteins to their receptors, low-density lipoprotein-related protein 5 and 6 (LRP5/6) and frizzled proteins, leading to phosphatidylinositol (4,5)bisphosphate (PtdIns(4,5)P2) production, signalosome formation, and LRP phosphorylation. However, the mechanism by which PtdIns(4,5)P2 regulates the signalosome formation remains unclear. Here we show that clathrin and adaptor protein 2 (AP2) were part of the LRP6 signalosomes. The presence of clathrin and AP2 in the LRP6 signalosomes depended on PtdIns(4,5)P2, and both clathrin and AP2 were required for the formation of LRP6 signalosomes. In addition, WNT3A-induced LRP6 signalosomes were primarily localized at cell surfaces, and WNT3A did not induce marked LRP6 internalization. However, rapid PtdIns(4,5)P2 hydrolysis induced artificially after WNT3A stimulation could lead to marked LRP6 internalization. Moreover, we observed WNT3A-induced LRP6 and clathrin clustering at cell surfaces using super-resolution fluorescence microscopy. Therefore, we conclude that PtdIns(4,5)P2 promotes the assembly of LRP6 signalosomes via the recruitment of AP2 and clathrin and that LRP6 internalization may not be a prerequisite for Wnt signaling to β-catenin stabilization.
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Affiliation(s)
- Ingyu Kim
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06510, USA
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31
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Moore FB, Baleja JD. Molecular remodeling mechanisms of the neural somatodendritic compartment. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1720-30. [PMID: 22705351 DOI: 10.1016/j.bbamcr.2012.06.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 06/06/2012] [Accepted: 06/07/2012] [Indexed: 12/28/2022]
Abstract
Neuronal cells use the process of vesicle trafficking to manipulate the populations of neurotransmitter receptors and other membrane proteins. Long term potentiation (LTP) is a long-lived increase in synaptic strength between neurons and increases postsynaptic dendritic spine size and the concentration of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate-type glutamate receptor (AMPAR) located in the postsynaptic density. AMPAR is removed from the cell surface via clathrin-mediated endocytosis. While the adaptor protein 2 (AP2) complex of endocytosis seems to have the components needed to allow temporal and spatial regulations of internalization, many accessory proteins are involved, such as epidermal growth factor receptor phosphorylation substrate 15 (Eps15). A sequence of repeats in the Eps15 protein is known as the Eps15 homology (EH) domain. It has affinity for asparagine-proline-phenylalanine (NPF) sequences that are contained within vesicle trafficking proteins such as epsin, Rab11 family interacting protein 2 (Rab11-FIP2), and Numb. After endocytosis, a pool of AMPAR is stored in the endosomal recycling compartment that can be transported to the dendritic spine surface upon stimulation during LTP for lateral diffusion into the postsynaptic density. Rab11 and the Eps15 homologue EHD1 are involved in receptor recycling. EHD family members are also involved in transcytosis of the neuronal cell adhesion molecule neuron-glia cell adhesion molecule (NgCAM) from the somatodendritic compartment to the axon. Neurons have a unique morphology comprising many projections of membrane that is constructed in part by the effects of the Eps15 homologue, intersectin. Morphogenesis in the somatodendritic compartment is becoming better understood, but there is still much exciting territory to explore, especially regarding the roles of various EH domain-NPF interactions in endocytic and recycling processes.
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Affiliation(s)
- Fletcher B Moore
- Department of Biochemistry, Tufts University School of Medicine, Boston, MA 02111, USA
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32
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Hsu VW, Bai M, Li J. Getting active: protein sorting in endocytic recycling. Nat Rev Mol Cell Biol 2012; 13:323-8. [PMID: 22498832 DOI: 10.1038/nrm3332] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Endocytic recycling returns proteins to the plasma membrane in many physiological contexts. Studies of these events have helped to elucidate fundamental mechanisms that underlie recycling. Recycling was for some time considered to be the exception to a general mechanism of active cargo sorting in multiple intracellular pathways. In recent years, studies have begun to reconcile this seeming disparity and also suggest explanations for why early recycling studies did not detect active sorting. Further articulation of this emerging trend has far-reaching implications for a deeper understanding of many physiological and pathological events that require recycling.
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Affiliation(s)
- Victor W Hsu
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, and Department of Medicine, Harvard Medical School, Boston, Massachsuetts 02115, USA.
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33
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Bucks MA, Murphy MA, O'Regan KJ, Courtney RJ. Identification of interaction domains within the UL37 tegument protein of herpes simplex virus type 1. Virology 2011; 416:42-53. [PMID: 21601231 DOI: 10.1016/j.virol.2011.04.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 01/03/2011] [Accepted: 04/26/2011] [Indexed: 12/16/2022]
Abstract
Herpes simplex virus type 1 (HSV-1) UL37 is a 1123 amino acid tegument protein that self-associates and binds to the tegument protein UL36 (VP1/2). Studies were undertaken to identify regions of UL37 involved in these protein-protein interactions. Coimmunoprecipitation assays showed that residues within the carboxy-terminal half of UL37, amino acids 568-1123, are important for interaction with UL36. Coimmunoprecipitation assays also revealed that amino acids 1-300 and 568-1123 of UL37 are capable of self-association. UL37 appears to self-associate only under conditions when UL36 is not present or is present in low amounts, suggesting UL36 and UL37 may compete for binding. Transfection-infection experiments were performed to identify domains of UL37 that complement the UL37 deletion virus, K∆UL37. The carboxy-terminal region of UL37 (residues 568-1123) partially rescues the K∆UL37 infection. These results suggest the C-terminus of UL37 may contribute to its essential functional role within the virus-infected cell.
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Affiliation(s)
- Michelle A Bucks
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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34
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HIV-1 Nef disrupts intracellular trafficking of major histocompatibility complex class I, CD4, CD8, and CD28 by distinct pathways that share common elements. J Virol 2011; 85:6867-81. [PMID: 21543478 DOI: 10.1128/jvi.00229-11] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The Nef protein is an important HIV virulence factor that promotes the degradation of host proteins to augment virus production and facilitate immune evasion. The best-characterized targets of Nef are major histocompatibility complex class I (MHC-I) and CD4, but Nef also has been reported to target several other proteins, including CD8β, CD28, CD80, CD86, and CD1d. To compare and contrast the effects of Nef on each protein, we constructed a panel of chimeric proteins in which the extracellular and transmembrane regions of the MHC-I allele HLA-A2 were fused to the cytoplasmic tails of CD4, CD28, CD8β, CD80, CD86, and CD1d. We found that Nef coprecipitated with and disrupted the expression of molecules with cytoplasmic tails from MHC-I HLA-A2, CD4, CD8β, and CD28, but Nef did not bind to or alter the expression of molecules with cytoplasmic tails from CD80, CD86, and CD1d. In addition, we used short interfering RNA (siRNA) knockdown and coprecipitation experiments to implicate AP-1 as a cellular cofactor for Nef in the downmodulation of both CD28 and CD8β. The interaction with AP-1 required for CD28 and CD8β differed from the AP-1 interaction required for MHC-I downmodulation in that it was mediated through the dileucine motif within Nef (LL(164,165)AA) and did not require the tyrosine binding pocket of the AP-1 μ subunit. In addition, we demonstrate a requirement for β-COP as a cellular cofactor for Nef that was necessary for the degradation of targeted molecules HLA-A2, CD4, and CD8. These studies provide important new information on the similarities and differences with which Nef affects intracellular trafficking and help focus future research on the best potential pharmaceutical targets.
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35
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Yu A, Xing Y, Harrison SC, Kirchhausen T. Structural analysis of the interaction between Dishevelled2 and clathrin AP-2 adaptor, a critical step in noncanonical Wnt signaling. Structure 2011; 18:1311-20. [PMID: 20947020 DOI: 10.1016/j.str.2010.07.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 07/21/2010] [Accepted: 07/22/2010] [Indexed: 01/22/2023]
Abstract
Wnt association with its receptor, Frizzled (Fz), and recruitment by the latter of an adaptor, Dishevelled (Dvl), initiates signaling through at least two distinct pathways ("canonical" and "noncanonical"). Endocytosis and compartmentalization help determine the signaling outcome. Our previous work has shown that Dvl2 links at least one Frizzled family member (Fz4) to clathrin-mediated endocytosis by interacting with the μ2 subunit of the AP-2 clathrin adaptor, through both a classical endocytic tyrosine motif and a so-called "DEP domain." We report here the crystal structure of a chimeric protein that mimics the Dvl2-μ2 complex. The DEP domain binds at one end of the elongated, C-terminal domain of μ2. This domain:domain interface shows that parts of the μ2 surface distinct from the tyrosine-motif site can help recruit specific receptors or adaptors into a clathrin coated pit. Mutation of residues at the DEP-μ2 contact or in the tyrosine motif reduce affinity of Dvl2 for μ2 and block efficient internalization of Fz4 in response to ligation by Wnt5a. The crystal structure has thus allowed us to identify the specific interaction that leads to Frizzled uptake and to downstream, noncanonical signaling events.
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Affiliation(s)
- Anan Yu
- Department of Cell Biology and Immune Disease Institute, Harvard Medical School, Boston, MA 02115, USA
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36
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Single-molecule analysis of a molecular disassemblase reveals the mechanism of Hsc70-driven clathrin uncoating. Nat Struct Mol Biol 2011; 18:295-301. [PMID: 21278753 PMCID: PMC3056279 DOI: 10.1038/nsmb.1985] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 11/23/2010] [Indexed: 11/13/2022]
Abstract
Heat shock cognate protein 70 (Hsc70) supports remodeling of protein complexes -- for example, disassembly of clathrin coats on endocytic coated vesicles. To understand how a simple ATP driven molecular clamp catalyzes a large-scale disassembly reaction, we have used single-particle fluorescence imaging to track the dynamics of Hsc70 and its clathrin substrate in real time. Hsc70 accumulates to a critical level, determined by kinetic modeling to be one Hsc70 for every two functional attachment sites; rapid, all-or-none uncoating then ensues. We propose that Hsc70 traps conformational distortions, seen previously by electron cryomicroscopy, in the vicinity of each occupied site and that accumulation of local strains destabilises the clathrin lattice. Capture of conformational fluctuations may be a general mechanism for chaperone-driven disassembly of protein complexes.
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37
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Mattera R, Boehm M, Chaudhuri R, Prabhu Y, Bonifacino JS. Conservation and diversification of dileucine signal recognition by adaptor protein (AP) complex variants. J Biol Chem 2011; 286:2022-30. [PMID: 21097499 PMCID: PMC3023499 DOI: 10.1074/jbc.m110.197178] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Indexed: 12/22/2022] Open
Abstract
The clathrin-associated, heterotetrameric adaptor protein (AP) complexes, AP-1, AP-2, and AP-3, recognize signals in the cytosolic domains of transmembrane proteins, leading to their sorting to endosomes, lysosomes, lysosome-related organelles, and/or the basolateral membrane of polarized epithelial cells. One type of signal, referred to as "dileucine-based," fits the consensus motif (D/E)XXXL(L/I). Previous biochemical analyses showed that (D/E)XXXL(L/I) signals bind to a combination of two subunits of each AP complex, namely the AP-1 γ-σ1, AP-2 α-σ2, and AP-3 δ-σ3 hemicomplexes, and structural studies revealed that an imperfect variant of this motif lacking the (D/E) residue binds to a site straddling the interface of α and σ2. Herein, we report mutational and binding analyses showing that canonical (D/E)XXXL(L/I) signals bind to this same site on AP-2, and to similar sites on AP-1 and AP-3. The strength and amino acid requirements of different interactions depend on the specific signals and AP complexes involved. We also demonstrate the occurrence of diverse AP-1 heterotetramers by combinatorial assembly of various γ and σ1 subunit isoforms encoded by different genes. These AP-1 variants bind (D/E)XXXL(L/I) signals with marked preferences for certain sequences, implying that they are not functionally equivalent. Our results thus demonstrate that different AP complexes share a conserved binding site for (D/E)XXXL(L/I) signals. However, the characteristics of the binding site on each complex vary, providing for the specific recognition of a diverse repertoire of (D/E)XXXL(L/I) signals.
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Affiliation(s)
- Rafael Mattera
- From the Cell Biology and Metabolism Program, NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Markus Boehm
- From the Cell Biology and Metabolism Program, NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Rittik Chaudhuri
- From the Cell Biology and Metabolism Program, NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Yogikala Prabhu
- From the Cell Biology and Metabolism Program, NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Juan S. Bonifacino
- From the Cell Biology and Metabolism Program, NICHD, National Institutes of Health, Bethesda, Maryland 20892
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38
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Li W, Puertollano R, Bonifacino JS, Overbeek PA, Everett ET. Disruption of the murine Ap2β1 gene causes nonsyndromic cleft palate. Cleft Palate Craniofac J 2010; 47:566-73. [PMID: 20500056 DOI: 10.1597/09-145] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Development of the secondary palate in mammals is a complex process that can be easily perturbed, leading to the common and distressing birth defect cleft palate. Animal models are particularly useful tools for dissecting underlying genetic components of cleft palate. We describe a new cleft palate model resulting from a transgene insertion mutation. Transgene insertional mutagenesis disrupts the genomic organization and expression of the Ap2β1 gene located on chromosome 11. This gene encodes the β2-adaptin subunit of the heterotetrameric adaptor protein 2 complex involved in clathrin-dependent endocytosis. Homozygous cleft palate mutant mice express no Ap2β1 messenger RNA or β2-adaptin protein and die during the perinatal period. Heterozygous mice are phenotypically normal despite expressing diminished β2-adaptin messenger RNA and protein compared with wildtype. Remarkably, the paralogous β1-adaptin subunit of the adaptor protein 1 complex partially substitutes for the missing β2-adaptin in embryonic fibroblasts from homozygous mutant mice, resulting in assembly of reduced levels of an adaptor protein 2 complex bearing β1-adaptin. This variant adaptor protein 2 complex is, therefore, apparently capable of maintaining viability of the homozygous mutant embryos until birth but insufficient to support palatogenesis. Nonsyndromic cleft palate in an animal model is associated with disruption of the Ap2β1 gene.
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Affiliation(s)
- Wei Li
- Department of Oral Facial Development, Indiana University School of Dentistry, Indianapolis, Indiana, USA
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Grygoruk A, Fei H, Daniels RW, Miller BR, Diantonio A, Krantz DE. A tyrosine-based motif localizes a Drosophila vesicular transporter to synaptic vesicles in vivo. J Biol Chem 2010; 285:6867-78. [PMID: 20053989 DOI: 10.1074/jbc.m109.073064] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vesicular neurotransmitter transporters must localize to synaptic vesicles (SVs) to allow regulated neurotransmitter release at the synapse. However, the signals required to localize vesicular proteins to SVs in vivo remain unclear. To address this question we have tested the effects of mutating proposed trafficking domains in Drosophila orthologs of the vesicular monoamine and glutamate transporters, DVMAT-A and DVGLUT. We show that a tyrosine-based motif (YXXY) is important both for DVMAT-A internalization from the cell surface in vitro, and localization to SVs in vivo. In contrast, DVGLUT deletion mutants that lack a putative C-terminal trafficking domain show more modest defects in both internalization in vitro and trafficking to SVs in vivo. Our data show for the first time that mutation of a specific trafficking motif can disrupt localization to SVs in vivo and suggest possible differences in the sorting of VMATs versus VGLUTs to SVs at the synapse.
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Affiliation(s)
- Anna Grygoruk
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, Hatos Center for Neuropharmacology, David Geffen School of Medicine, UCLA, Los Angeles, California 90095-1761, USA
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40
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Spatiotemporal regulation of intracellular trafficking of Toll-like receptor 9 by an inhibitory receptor, Ly49Q. Blood 2009; 114:1518-27. [PMID: 19528537 DOI: 10.1182/blood-2008-12-192344] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Toll-like receptor (TLR) 9 recognizes unmethylated microorganismal cytosine guanine dinucleotide (CpG) DNA and elicits innate immune responses. However, the regulatory mechanisms of the TLR signaling remain elusive. We recently reported that Ly49Q, an immunoreceptor tyrosine-based inhibitory motif-bearing inhibitory receptor belonging to the natural killer receptor family, is crucial for TLR9-mediated type I interferon production by plasmacytoid dendritic cells. Ly49Q is expressed in plasmacytoid dendritic cells, macrophages, and neutrophils, but not natural killer cells. In this study, we showed that Ly49Q regulates TLR9 signaling by affecting endosome/lysosome behavior. Ly49Q colocalized with CpG in endosome/lysosome compartments. Cells lacking Ly49Q showed a disturbed redistribution of TLR9 and CpG. In particular, CpG-induced tubular endolysosomal extension was impaired in the absence of Ly49Q. Consistent with these findings, cells lacking Ly49Q showed impaired cytokine production in response to CpG-oligodeoxynucleotide. Our data highlight a novel mechanism by which TLR9 signaling is controlled through the spatiotemporal regulation of membrane trafficking by the immunoreceptor tyrosine-based inhibitory motif-bearing receptor Ly49Q.
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41
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Chao WT, Kunz J. Focal adhesion disassembly requires clathrin-dependent endocytosis of integrins. FEBS Lett 2009; 583:1337-43. [PMID: 19306879 DOI: 10.1016/j.febslet.2009.03.037] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 03/15/2009] [Accepted: 03/18/2009] [Indexed: 10/21/2022]
Abstract
Cell migration requires the controlled disassembly of focal adhesions, but the underlying mechanisms remain poorly understood. Here, we show that adhesion turnover is mediated through dynamin- and clathrin-dependent endocytosis of activated beta1 integrins. Consistent with this, clathrin and the clathrin adaptors AP-2 and disabled-2 (DAB2) distribute along with dynamin 2 to adhesion sites prior to adhesion disassembly. Moreover, knockdown of either dynamin 2 or both clathrin adaptors blocks beta1 integrin internalization, leading to impaired focal adhesion disassembly and cell migration. Together, these results provide important insight into the mechanisms underlying adhesion disassembly and identify novel components of the disassembly pathway.
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Affiliation(s)
- Wei-Ting Chao
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, 1 Baylor Plaza, BCM335, RM T419, Houston, TX 77030, USA
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42
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Wang X, Herr RA, Hansen T. Viral and cellular MARCH ubiquitin ligases and cancer. Semin Cancer Biol 2008; 18:441-50. [PMID: 18948196 DOI: 10.1016/j.semcancer.2008.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 09/26/2008] [Indexed: 11/18/2022]
Abstract
Covalent conjugation of proteins with ubiquitin is one the most important post-translational modifications because it controls intracellular protein trafficking typically resulting in protein degradation. Frequently ubiquitinated proteins are targeted to the proteasome for degradation in the cytosol. However, ubiquitinated membrane bound proteins can also be targeted for endocytosis and degradation in the lysosome. Ubiquitin-dependent degradation pathways have clear cancer relevance due to their integral involvement in protein quality control, regulation of immune responses, signal transduction, and cell cycle regulation. In spite of its fundamental importance, little is known regarding how proteins are specifically identified for ubiquitin-dependent degradation. In this article we review a newly discovered family of viral and cellular ubiquitin ligases called MARCH proteins. Recent studies of MARCH proteins define new paradigms showing how ubiquitin E3 ligases determine the intracellular location and fate of proteins.
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Affiliation(s)
- Xiaoli Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
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43
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Lan H, Liu Y, Bell MI, Gurevich VV, Neve KA. A dopamine D2 receptor mutant capable of G protein-mediated signaling but deficient in arrestin binding. Mol Pharmacol 2008; 75:113-23. [PMID: 18809670 DOI: 10.1124/mol.108.050534] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Arrestins mediate G protein-coupled receptor desensitization, internalization, and signaling. Dopamine D(2) and D(3) receptors have similar structures but distinct characteristics of interaction with arrestins. The goals of this study were to compare arrestin-binding determinants in D(2) and D(3) receptors other than phosphorylation sites and to create a D(2) receptor that is deficient in arrestin binding. We first assessed the ability of purified arrestins to bind to glutathione transferase (GST) fusion proteins containing the receptor third intracellular loops (IC3). Arrestin3 bound to IC3 of both D(2) and D(3) receptors, with the affinity and localization of the binding site indistinguishable between the receptor subtypes. Mutagenesis of the GST-IC3 fusion proteins identified an important determinant of the binding of arrestin3 in the N-terminal region of IC3. Alanine mutations of this determinant (IYIV212-215) in the full-length D(2) receptor generated a signaling-biased receptor with intact ligand binding and G-protein coupling and activation, but deficient in receptor-mediated arrestin3 translocation to the membrane, agonist-induced receptor internalization, and agonist-induced desensitization in human embryonic kidney 293 cells. This mutation also decreased arrestin-dependent activation of extracellular signal-regulated kinases. The finding that nonphosphorylated D(2)-IC3 and D(3)-IC3 have similar affinity for arrestin is consistent with previous suggestions that the differential effects of D(2) and D(3) receptor activation on membrane translocation of arrestin and receptor internalization are due, at least in part, to differential phosphorylation of the receptors. In addition, these results imply that the sequence IYIV212-215 at the N terminus of IC3 of the D(2) receptor is a key element of the arrestin binding site.
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Affiliation(s)
- Hongxiang Lan
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon, USA
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44
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Han J, Wang Y, Wang S, Chi C. Interaction of Mint3 with Furin regulates the localization of Furin in the trans-Golgi network. J Cell Sci 2008; 121:2217-23. [PMID: 18544638 DOI: 10.1242/jcs.019745] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Furin is a proprotein convertase that cycles between the plasma membrane, endosomes and the trans-Golgi network (TGN), maintaining a predominant distribution in the latter. Mint3, a member of the Mint protein family, is involved in the signaling and trafficking of membrane proteins. Until now, little has been known about the roles of Mint3 in the localization or trafficking of Furin. Here, using co-immunoprecipitation and immunofluorescence assays, we show that Mint3 interacts with Furin in the Golgi compartment of HeLa cells. Knockdown of endogenous Mint3 expression by RNA interference disrupts the TGN-specific localization of Furin and increases its distribution in endosomes. We further demonstrate that the phosphotyrosine-binding (PTB) domain of Mint3 is essential for the binding of Furin and that this binding affects the TGN-specific localization of Furin. Moreover, mutation studies of Furin indicate that Mint3 regulates Furin distribution mainly through interaction with the acidic peptide signal of Furin. Collectively, these data suggest that the interaction between the PTB domain of Mint3 and the acidic peptide signal of Furin regulates the specific localization of Furin in the TGN.
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Affiliation(s)
- Jinbo Han
- Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, People's Republic of China
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45
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Pandey MS, Harris EN, Weigel JA, Weigel PH. The cytoplasmic domain of the hyaluronan receptor for endocytosis (HARE) contains multiple endocytic motifs targeting coated pit-mediated internalization. J Biol Chem 2008; 283:21453-61. [PMID: 18539600 DOI: 10.1074/jbc.m800886200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The hyaluronic acid (HA) receptor for endocytosis (HARE) is the primary scavenger receptor for HA and chondroitin sulfates in mammals. The two human isoforms of HARE (full-length 315-kDa and a 190-kDa proteolytic cleavage product), which are type I single-pass membrane proteins, are highly expressed in sinusoidal endothelial cells of lymph nodes, liver, and spleen. Their identical HARE cytoplasmic domains contain four candidate AP-2/clathrin-mediated endocytic signaling motifs as follows: YSYFRI(2485), FQHF(2495), NPLY(2519), and DPF(2534) (315-HARE numbering). Stably transfected cells expressing 190-HARE(DeltaYSYFRI), 190-HARE(DeltaFQHF), or 190-HARE(DeltaNPLY) (lacking Motifs 1, 2, or 3) had decreased (125)I-HA endocytosis rates of approximately 49, approximately 39, and approximately 56%, respectively (relative to wild type). In contrast, 190-HARE(DeltaDPF) cells (lacking Motif 4) showed no change in HA endocytic rate. Deletions of motifs 1 and 2 or of 1, 2, and 4 decreased the rate of HA endocytosis by only approximately 41%. Endocytosis was approximately 95% decreased in mutants lacking all four motifs. Cells expressing a 190-HARE(Y2519A) mutant of the NPLY motif retained 85-90% of wild type endocytosis, whereas this mutation in the triple motif deletant decreased endocytosis to approximately 7% of wild type. Tyr in NPLY(2519) is thus important for endocytosis. All HARE mutants showed similar HA binding and degradation of the internalized HA, indicating that altering endocytic motifs did not affect ectodomain binding of HA or targeting of internalized HA to lysosomes. We conclude that, although NPLY may be the most important motif, it functions together with two other endocytic motifs; thus three signal sequences (YSYFRI, FQHF, and NPLY) provide redundancy to mediate coated pit targeting and endocytosis of HARE.
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Affiliation(s)
- Madhu S Pandey
- Department of Biochemistry and Molecular Biology, and Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190, USA
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46
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NPXY motifs in the beta1 integrin cytoplasmic tail are required for functional reovirus entry. J Virol 2008; 82:3181-91. [PMID: 18216114 DOI: 10.1128/jvi.01612-07] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Reovirus cell entry is mediated by attachment to cell surface carbohydrate and junctional adhesion molecule A (JAM-A) and internalization by beta1 integrin. The beta1 integrin cytoplasmic tail contains two NPXY motifs, which function in recruitment of adaptor proteins and clathrin for endocytosis and serve as sorting signals for internalized cargo. As reovirus infection requires disassembly in the endocytic compartment, we investigated the role of the beta1 integrin NPXY motifs in reovirus internalization. In comparison to wild-type cells (beta1+/+ cells), reovirus infectivity was significantly reduced in cells expressing mutant beta1 integrin in which the NPXY motifs were altered to NPXF (beta1+/+Y783F/Y795F cells). However, reovirus displayed equivalent binding and internalization levels following adsorption to beta1+/+ cells and beta1+/+Y783F/Y795F cells, suggesting that the NPXY motifs are essential for transport of reovirus within the endocytic pathway. Reovirus entry into beta1+/+ cells was blocked by chlorpromazine, an inhibitor of clathrin-mediated endocytosis, while entry into beta1+/+Y783F/Y795F cells was unaffected. Furthermore, virus was distributed to morphologically distinct endocytic organelles in beta1+/+ and beta1+/+Y783F/Y795F cells, providing further evidence that the beta1 integrin NPXY motifs mediate sorting of reovirus in the endocytic pathway. Thus, NPXY motifs in the beta1 integrin cytoplasmic tail are required for functional reovirus entry, which indicates a key role for these sequences in endocytosis of a pathogenic virus.
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47
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Mason AK, Jacobs BE, Welling PA. AP-2-dependent internalization of potassium channel Kir2.3 is driven by a novel di-hydrophobic signal. J Biol Chem 2008; 283:5973-84. [PMID: 18180291 DOI: 10.1074/jbc.m709756200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The localization and density of Kir2.3 channels are influenced by the balance between PDZ protein interaction at the cell surface and routing into the endocytic pathway. Here, we explore mechanisms by which the Kir2.3 channel is directed into the endocytic pathway. We found that Kir2.3 channels are constitutively internalized from the cell surface in a dynamin-dependent manner, indicative of vesicle-mediated endocytosis. The rate of Kir2.3 endocytosis was dramatically attenuated following RNA interference-mediated knockdown of either alpha adaptin (AP-2 clathrin adaptor) or clathrin heavy chain, revealing that Kir2.3 is internalized by an AP-2 clathrin-dependent mechanism. Structure-rationalized mutagenesis studies of a number of different potential AP-2 interaction motifs indicate that internalization of Kir2.3 is largely dependent on a non-canonical di-isoleucine motif (II413) embedded within the C terminus. Internalization assays using CD4-Kir2.3 chimeras demonstrate that the di-isoleucine signal acts in an autonomous and transplantable manner. Kir2.3 co-immunoprecipitates with alpha adaptin, and disruption of the di-isoleucine motif decreased interaction of the channel with AP-2. Replacement of the di-isoleucine motif with a canonical di-leucine internalization signal actually blocked Kir2.3 endocytosis. Moreover, in yeast three-hybrid studies, the Kir2.3 di-isoleucine motif does not bind the AP-2 alphaC-sigma2 hemicomplex in the way that has been recently observed for canonical di-leucine signals. Altogether, the results indicate that Kir2.3 channels are marked for clathrin-dependent internalization from the plasma membrane by a novel AP-2-dependent signal.
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Affiliation(s)
- Amanda K Mason
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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48
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49
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Wonderlich ER, Williams M, Collins KL. The tyrosine binding pocket in the adaptor protein 1 (AP-1) mu1 subunit is necessary for Nef to recruit AP-1 to the major histocompatibility complex class I cytoplasmic tail. J Biol Chem 2007; 283:3011-3022. [PMID: 18073204 DOI: 10.1074/jbc.m707760200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
To evade the anti-human immunodeficiency virus (HIV) immune response, the HIV Nef protein disrupts major histocompatibility complex class I (MHC-I) trafficking by recruiting the clathrin adaptor protein 1 (AP-1) to the MHC-I cytoplasmic tail. Under normal conditions AP-1 binds dileucine and tyrosine signals (YXX phi motifs) via physically separate binding sites. In the case of the Nef-MHC-I complex, a tyrosine in the human leukocyte antigen (HLA)-A2 cytoplasmic tail ((320)YSQA) and a methionine in Nef (Met(20)) are absolutely required for AP-1 binding. Also present in Nef is a dileucine motif, which does not normally affect MHC-I trafficking and is not needed to recruit AP-1 to the Nef-MHC-I-complex. However, evidence is presented here that this dileucine motif can be activated by fusing Nef to the HLA-A2 tail in cis. Thus, the inability of this motif to function in trans likely results from a structural change that occurs when Nef binds to the MHC-I cytoplasmic tail. The physiologically relevant tyrosine-dependent recruitment of AP-1 to MHC-I, which occurs whether Nef is present in cis or trans, was stabilized by the acidic and polyproline domains within Nef. Additionally, amino acids Ala(324) and Asp(327) in the cytoplasmic tails of HLA-A and (but not HLA-C and HLA-E) molecules also stabilized AP-1 binding. Finally, mutation of the tyrosine binding pocket in the mu subunit of AP-1 created a dominant negative inhibitor of Nef-induced down-modulation of HLA-A2 that disrupted binding of wild type AP-1 to the Nef-MHC-I complex. Thus, these data provide evidence that Nef binding to the MHC-I cytoplasmic tail stabilizes the interaction of a tyrosine in the MHC-I cytoplasmic tail with the natural tyrosine binding pocket in AP-1.
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Affiliation(s)
- Elizabeth R Wonderlich
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Maya Williams
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Kathleen L Collins
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, Michigan 48109; Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan 48109; Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109.
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50
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Rollason R, Korolchuk V, Hamilton C, Schu P, Banting G. Clathrin-mediated endocytosis of a lipid-raft-associated protein is mediated through a dual tyrosine motif. J Cell Sci 2007; 120:3850-8. [DOI: 10.1242/jcs.003343] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We have previously shown that the integral membrane protein CD317 has both a conventional transmembrane domain near its N-terminus and a C-terminal glycosyl-phosphatidylinositol (GPI) anchor. With the possible exception of a minor topological variant of the prion protein, there remain no other convincing examples of a mammalian protein with such a topology. CD317 is localised to cholesterol-rich lipid microdomains (`lipid rafts') in the plasma membrane and is internalised from the cell surface for delivery to a juxta-nuclear compartment (most probably the TGN). We have now investigated the mechanism by which CD317 is internalised and find that this raft-associated integral membrane protein is internalised through a clathrin-dependent pathway, internalisation is dependent upon a novel dual-tyrosine-based motif in the cytosolic domain of CD317, the cytosolic domain of CD317 can interact with the μ subunits of the AP2 and AP1 adaptor complexes, interaction with AP1 is required for delivery of CD317 back to the TGN, and removal of the GPI anchor from CD317 reduces the efficiency of CD317 internalisation. Collectively, these data indicate that CD317 is internalised and delivered back to the TGN by the sequential action of AP2 and AP1 adaptor complexes and that, surprisingly, the clathrin-mediated internalisation of CD317 occurs more efficiently if CD317 is localised to lipid rafts.
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Affiliation(s)
- Ruth Rollason
- Department of Biochemistry, University of Bristol, Bristol, BS8 1T, UK
| | - Viktor Korolchuk
- Department of Biochemistry, University of Bristol, Bristol, BS8 1T, UK
| | - Clare Hamilton
- Department of Biochemistry, University of Bristol, Bristol, BS8 1T, UK
| | - Peter Schu
- Zentrum für Biochemie und Molekulare Zellbiologie, Universität Goettingen, Germany
| | - George Banting
- Department of Biochemistry, University of Bristol, Bristol, BS8 1T, UK
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