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Lee YJ, Shin KJ, Jang HJ, Ryu JS, Lee CY, Yoon JH, Seo JK, Park S, Lee S, Je AR, Huh YH, Kong SY, Kwon T, Suh PG, Chae YC. GPR143 controls ESCRT-dependent exosome biogenesis and promotes cancer metastasis. Dev Cell 2023; 58:320-334.e8. [PMID: 36800996 DOI: 10.1016/j.devcel.2023.01.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 10/17/2022] [Accepted: 01/26/2023] [Indexed: 02/18/2023]
Abstract
Exosomes transport a variety of macromolecules and modulate intercellular communication in physiology and disease. However, the regulation mechanisms that determine exosome contents during exosome biogenesis remain poorly understood. Here, we find that GPR143, an atypical GPCR, controls the endosomal sorting complex required for the transport (ESCRT)-dependent exosome biogenesis pathway. GPR143 interacts with HRS (an ESCRT-0 Subunit) and promotes its association to cargo proteins, such as EGFR, which subsequently enables selective protein sorting into intraluminal vesicles (ILVs) in multivesicular bodies (MVBs). GPR143 is elevated in multiple cancers, and quantitative proteomic and RNA profiling of exosomes in human cancer cell lines showed that the GPR143-ESCRT pathway promotes secretion of exosomes that carry unique cargo, including integrins signaling proteins. Through gain- and loss-of-function studies in mice, we show that GPR143 promotes metastasis by secreting exosomes and increasing cancer cell motility/invasion through the integrin/FAK/Src pathway. These findings provide a mechanism for regulating the exosomal proteome and demonstrate its ability to promote cancer cell motility.
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Affiliation(s)
- Yu Jin Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Kyeong Jin Shin
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Hyun-Jun Jang
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jin-Sun Ryu
- Division of Translational Science, Research Institute and Hospital, National Cancer Center, Goyang 10408, Republic of Korea
| | - Chae Young Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jong Hyuk Yoon
- Korea Brain Research Institute (KBRI), Daegu 41062, Republic of Korea
| | - Jeong Kon Seo
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Sabin Park
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Semin Lee
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - A Reum Je
- Electron Microscopy Research Center, Korea Basic Science Institute (KBSI), Cheongju 28119, Republic of Korea
| | - Yang Hoon Huh
- Electron Microscopy Research Center, Korea Basic Science Institute (KBSI), Cheongju 28119, Republic of Korea
| | - Sun-Young Kong
- Division of Translational Science, Research Institute and Hospital, National Cancer Center, Goyang 10408, Republic of Korea; Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Republic of Korea
| | - Taejoon Kwon
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Pann-Ghill Suh
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea; Korea Brain Research Institute (KBRI), Daegu 41062, Republic of Korea.
| | - Young Chan Chae
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
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2
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Bueschbell B, Manga P, Schiedel AC. The Many Faces of G Protein-Coupled Receptor 143, an Atypical Intracellular Receptor. Front Mol Biosci 2022; 9:873777. [PMID: 35495622 PMCID: PMC9039016 DOI: 10.3389/fmolb.2022.873777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/10/2022] [Indexed: 12/24/2022] Open
Abstract
GPCRs transform extracellular stimuli into a physiological response by activating an intracellular signaling cascade initiated via binding to G proteins. Orphan G protein-coupled receptors (GPCRs) hold the potential to pave the way for development of new, innovative therapeutic strategies. In this review we will introduce G protein-coupled receptor 143 (GPR143), an enigmatic receptor in terms of classification within the GPCR superfamily and localization. GPR143 has not been assigned to any of the GPCR families due to the lack of common structural motifs. Hence we will describe the most important motifs of classes A and B and compare them to the protein sequence of GPR143. While a precise function for the receptor has yet to be determined, the protein is expressed abundantly in pigment producing cells. Many GPR143 mutations cause X-linked Ocular Albinism Type 1 (OA1, Nettleship-Falls OA), which results in hypopigmentation of the eyes and loss of visual acuity due to disrupted visual system development and function. In pigment cells of the skin, loss of functional GPR143 results in abnormally large melanosomes (organelles in which pigment is produced). Studies have shown that the receptor is localized internally, including at the melanosomal membrane, where it may function to regulate melanosome size and/or facilitate protein trafficking to the melanosome through the endolysosomal system. Numerous additional roles have been proposed for GPR143 in determining cancer predisposition, regulation of blood pressure, development of macular degeneration and signaling in the brain, which we will briefly describe as well as potential ligands that have been identified. Furthermore, GPR143 is a promiscuous receptor that has been shown to interact with multiple other melanosomal proteins and GPCRs, which strongly suggests that this orphan receptor is likely involved in many different physiological actions.
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Affiliation(s)
- Beatriz Bueschbell
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, University of Bonn, Bonn, Germany
| | - Prashiela Manga
- Ronald O. Perelman Department of Dermatology, Grossman School of Medicine, New York University, New York City, NY, United States
| | - Anke C. Schiedel
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, University of Bonn, Bonn, Germany
- *Correspondence: Anke C. Schiedel,
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3
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Le L, Sirés-Campos J, Raposo G, Delevoye C, Marks MS. Melanosome Biogenesis in the Pigmentation of Mammalian Skin. Integr Comp Biol 2021; 61:1517-1545. [PMID: 34021746 PMCID: PMC8516112 DOI: 10.1093/icb/icab078] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Melanins, the main pigments of the skin and hair in mammals, are synthesized within membrane-bound organelles of melanocytes called melanosomes. Melanosome structure and function are determined by a cohort of resident transmembrane proteins, many of which are expressed only in pigment cells and localize specifically to melanosomes. Defects in the genes that encode melanosome-specific proteins or components of the machinery required for their transport in and out of melanosomes underlie various forms of ocular or oculocutaneous albinism, characterized by hypopigmentation of the hair, skin, and eyes and by visual impairment. We review major components of melanosomes, including the enzymes that catalyze steps in melanin synthesis from tyrosine precursors, solute transporters that allow these enzymes to function, and structural proteins that underlie melanosome shape and melanin deposition. We then review the molecular mechanisms by which these components are biosynthetically delivered to newly forming melanosomes-many of which are shared by other cell types that generate cell type-specific lysosome-related organelles. We also highlight unanswered questions that need to be addressed by future investigation.
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Affiliation(s)
- Linh Le
- Department of Pathology & Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Julia Sirés-Campos
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, Paris, 75005, France
| | - Graça Raposo
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, Paris, 75005, France
| | - Cédric Delevoye
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, Paris, 75005, France
| | - Michael S Marks
- Department of Pathology & Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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4
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Patwardhan A, Cheng N, Trejo J. Post-Translational Modifications of G Protein-Coupled Receptors Control Cellular Signaling Dynamics in Space and Time. Pharmacol Rev 2021; 73:120-151. [PMID: 33268549 PMCID: PMC7736832 DOI: 10.1124/pharmrev.120.000082] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are a large family comprising >800 signaling receptors that regulate numerous cellular and physiologic responses. GPCRs have been implicated in numerous diseases and represent the largest class of drug targets. Although advances in GPCR structure and pharmacology have improved drug discovery, the regulation of GPCR function by diverse post-translational modifications (PTMs) has received minimal attention. Over 200 PTMs are known to exist in mammalian cells, yet only a few have been reported for GPCRs. Early studies revealed phosphorylation as a major regulator of GPCR signaling, whereas later reports implicated a function for ubiquitination, glycosylation, and palmitoylation in GPCR biology. Although our knowledge of GPCR phosphorylation is extensive, our knowledge of the modifying enzymes, regulation, and function of other GPCR PTMs is limited. In this review we provide a comprehensive overview of GPCR post-translational modifications with a greater focus on new discoveries. We discuss the subcellular location and regulatory mechanisms that control post-translational modifications of GPCRs. The functional implications of newly discovered GPCR PTMs on receptor folding, biosynthesis, endocytic trafficking, dimerization, compartmentalized signaling, and biased signaling are also provided. Methods to detect and study GPCR PTMs as well as PTM crosstalk are further highlighted. Finally, we conclude with a discussion of the implications of GPCR PTMs in human disease and their importance for drug discovery. SIGNIFICANCE STATEMENT: Post-translational modification of G protein-coupled receptors (GPCRs) controls all aspects of receptor function; however, the detection and study of diverse types of GPCR modifications are limited. A thorough understanding of the role and mechanisms by which diverse post-translational modifications regulate GPCR signaling and trafficking is essential for understanding dysregulated mechanisms in disease and for improving and refining drug development for GPCRs.
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Affiliation(s)
- Anand Patwardhan
- Department of Pharmacology and the Biomedical Sciences Graduate Program, School of Medicine, University of California, San Diego, La Jolla, California
| | - Norton Cheng
- Department of Pharmacology and the Biomedical Sciences Graduate Program, School of Medicine, University of California, San Diego, La Jolla, California
| | - JoAnn Trejo
- Department of Pharmacology and the Biomedical Sciences Graduate Program, School of Medicine, University of California, San Diego, La Jolla, California
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5
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Davies BA, Morton LO, Jefferson JR, Rozeveld CN, Doskey LC, LaRusso NF, Katzmann DJ. Polarized human cholangiocytes release distinct populations of apical and basolateral small extracellular vesicles. Mol Biol Cell 2020; 31:2463-2474. [PMID: 32845745 PMCID: PMC7851850 DOI: 10.1091/mbc.e19-03-0133] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Intercellular communication is critical for organismal homeostasis, and defects can contribute to human disease states. Polarized epithelial cells execute distinct signaling agendas via apical and basolateral surfaces to communicate with different cell types. Small extracellular vesicles (sEVs), including exosomes and small microvesicles, represent an understudied form of intercellular communication in polarized cells. Human cholangiocytes, epithelial cells lining bile ducts, were cultured as polarized epithelia in a Transwell system as a model with which to study polarized sEV communication. Characterization of isolated apically and basolaterally released EVs revealed enrichment in sEVs. However, differences in apical and basolateral sEV composition and numbers were observed. Genetic or pharmacological perturbation of cellular machinery involved in the biogenesis of intralumenal vesicles at endosomes (the source of exosomes) revealed general and domain-specific effects on sEV biogenesis/release. Additionally, analyses of signaling revealed distinct profiles of activation depending on sEV population, target cell, and the function of the endosomal sorting complex required for transport (ESCRT)-associated factor ALG-2–interacting protein X (ALIX) within the donor cells. These results support the conclusion that polarized cholangiocytes release distinct sEV pools to mediate communication via their apical and basolateral domains and suggest that defective ESCRT function may contribute to disease states through altered sEV signaling.
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Affiliation(s)
- Brian A Davies
- Biochemistry and Molecular Biology Department, Mayo Clinic, Rochester, MN 55905
| | - Leslie O Morton
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905
| | - John R Jefferson
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905.,Chemistry Department, Luther College, Decorah, IA 52101
| | - Cody N Rozeveld
- Biochemistry and Molecular Biology Department, Mayo Clinic, Rochester, MN 55905.,Mayo Clinic Graduate School of Biomedical Science, Mayo Clinic, Rochester, MN 55905
| | - Luke C Doskey
- Biochemistry and Molecular Biology Department, Mayo Clinic, Rochester, MN 55905.,Mayo Clinic Graduate School of Biomedical Science, Mayo Clinic, Rochester, MN 55905
| | - Nicholas F LaRusso
- Biochemistry and Molecular Biology Department, Mayo Clinic, Rochester, MN 55905.,Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905
| | - David J Katzmann
- Biochemistry and Molecular Biology Department, Mayo Clinic, Rochester, MN 55905.,Mayo Clinic Graduate School of Biomedical Science, Mayo Clinic, Rochester, MN 55905
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6
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Bebelman MP, Crudden C, Pegtel DM, Smit MJ. The Convergence of Extracellular Vesicle and GPCR Biology. Trends Pharmacol Sci 2020; 41:627-640. [PMID: 32711926 DOI: 10.1016/j.tips.2020.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 02/07/2023]
Abstract
Transmembrane receptors, of which G protein-coupled receptors (GPCRs) constitute the largest group, typically act as cellular antennae that reside at the plasma membrane (PM) to collect and interpret information from the extracellular environment. The discovery of cell-released extracellular vesicles (EVs) has added a new dimension to intercellular communication. These unique nanocarriers reflect cellular topology and can systemically transport functionally competent transmembrane receptors, ligands, and a cargo of signal proteins. Recent developments hint at roles for GPCRs in the EV life cycle and, conversely, at roles for EVs in GPCR signal transduction. We highlight key points of convergence, discuss their relevance to current GPCR and EV paradigms, and speculate on how this intersection could lend itself to future therapeutic avenues.
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Affiliation(s)
- Maarten P Bebelman
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands; Department of Pathology, Cancer Center Amsterdam, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Caitrin Crudden
- Department of Pathology, Cancer Center Amsterdam, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - D Michiel Pegtel
- Department of Pathology, Cancer Center Amsterdam, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Martine J Smit
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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7
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Single Cell Fluorescence Ratio Image Analysis for Studying ESCRT Function in Receptor Trafficking. Methods Mol Biol 2019; 1998:93-103. [PMID: 31250296 DOI: 10.1007/978-1-4939-9492-2_7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The endosomal sorting complexes required for transport (ESCRT) comprise a major trafficking pathway for plasma membrane proteins and are fundamental for ubiquitin-dependent cargo endocytosis. Here, we describe a method for studying the effect of ESCRT complexes on endo-lysosomal membrane trafficking and their role in receptor integrin α5β1 downregulation. Single cell fluorescence ratio image analysis (FRIA), using appropriate fluorescence probes, enables the measurement of dynamics of integrin α5β1 containing vesicles and represents a live cell-based method for studying the role of ESCRTs.
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8
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Jovancevic N, Khalfaoui S, Weinrich M, Weidinger D, Simon A, Kalbe B, Kernt M, Kampik A, Gisselmann G, Gelis L, Hatt H. Odorant Receptor 51E2 Agonist β-ionone Regulates RPE Cell Migration and Proliferation. Front Physiol 2017; 8:888. [PMID: 29249973 PMCID: PMC5714887 DOI: 10.3389/fphys.2017.00888] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/19/2017] [Indexed: 01/09/2023] Open
Abstract
The odorant receptor 51E2 (OR51E2), which is well-characterized in prostate cancer cells and epidermal pigment cells, was identified for the first time as the most highly expressed OR in human fetal and adult retinal pigment epithelial (RPE) cells. Immunofluorescence staining and Western blot analysis revealed OR51E2 localization throughout the cytosol and in the plasma membrane. Additionally, immunohistochemical staining of diverse layers of the eye showed that the expression of OR51E2 is restricted to the pigment cells of the RPE and choroid. The results of Ca2+-imaging experiments demonstrate that activation of OR51E2 triggers a Ca2+ dependent signal pathway in RPE cells. Downstream signaling of OR51E2 involves the activation of adenylyl cyclase, ERK1/2 and AKT. The activity of these protein kinases likely accounts for the demonstrated increase in the migration and proliferation of RPE cells upon stimulation with the OR51E2 ligand β-ionone. These findings suggest that OR51E2 is involved in the regulation of RPE cell growth. Thus, OR51E2 represents a potential target for the treatment of proliferative disorders.
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Affiliation(s)
| | | | | | | | - Annika Simon
- Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Benjamin Kalbe
- Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Marcus Kernt
- Ophthalmology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Anselm Kampik
- Ophthalmology, Ludwig Maximilian University of Munich, Munich, Germany
| | | | - Lian Gelis
- Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Hanns Hatt
- Cell Physiology, Ruhr-University Bochum, Bochum, Germany
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9
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Szymanska E, Budick-Harmelin N, Miaczynska M. Endosomal "sort" of signaling control: The role of ESCRT machinery in regulation of receptor-mediated signaling pathways. Semin Cell Dev Biol 2017; 74:11-20. [PMID: 28797837 DOI: 10.1016/j.semcdb.2017.08.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 07/24/2017] [Accepted: 08/04/2017] [Indexed: 12/31/2022]
Abstract
The endosomal sorting complexes required for transport (ESCRTs) machinery consists of four protein assemblies (ESCRT-0 to -III subcomplexes) which mediate various processes of membrane remodeling in the cell. In the endocytic pathway, ESCRTs sort cargo destined for degradation into intraluminal vesicles (ILVs) of endosomes. Cargos targeted by ESCRTs include various signaling molecules, mainly internalized cell-surface receptors but also some cytosolic proteins. It is therefore expected that aberrant trafficking caused by ESCRT dysfunction affects different signaling pathways. Here we review how perturbation of ESCRT activity alters intracellular transport of membrane receptors, causing their accumulation on endocytic compartments, decreased degradation and/or altered recycling to the plasma membrane. We further describe how perturbed trafficking of receptors impacts the activity of their downstream signaling pathways, with or without changes in transcriptional responses. Finally, we present evidence that ESCRT components can also control activity and intracellular distribution of cytosolic signaling proteins (kinases, other effectors and soluble receptors). The underlying mechanisms involve sequestration of such proteins in ILVs, their sorting for degradation or towards non-lysosomal destinations, and regulating their availability in various cellular compartments. All these ESCRT-mediated processes can modulate final outputs of multiple signaling pathways.
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Affiliation(s)
- Ewelina Szymanska
- Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Noga Budick-Harmelin
- Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Warsaw, Poland; Cell Research and Immunology Department, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel
| | - Marta Miaczynska
- Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Warsaw, Poland.
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10
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Gioria M, Pasini ME, Berruti G. Dynamic of contribution of UBPy-sorted cargo to acrosome biogenesis: effects of its derailment in a mouse model of globozoospermia, the infertile Vps54 (L967Q) mutant. Cell Tissue Res 2017; 369:413-427. [DOI: 10.1007/s00441-017-2592-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/21/2017] [Indexed: 12/14/2022]
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11
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Dauner K, Eid W, Raghupathy R, Presley JF, Zha X. mTOR complex 1 activity is required to maintain the canonical endocytic recycling pathway against lysosomal delivery. J Biol Chem 2017; 292:5737-5747. [PMID: 28196862 DOI: 10.1074/jbc.m116.771451] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 02/10/2017] [Indexed: 12/30/2022] Open
Abstract
The plasma membrane of mammalian cells undergoes constitutive endocytosis, endocytic sorting, and recycling, which delivers nutrients to the lysosomes. The receptors, along with membrane lipids, are normally returned to the plasma membrane to sustain this action. It is not known, however, whether this process is influenced by metabolic conditions. Here we report that endocytic recycling requires active mechanistic target of rapamycin (aka mammalian target of rapamycin) (mTORC1), a master metabolic sensor. Upon mTORC1 inactivation, either by starvation or by inhibitor, recycling receptors and plasma membrane lipids, such as transferrin receptors and sphingomyelin, are delivered to the lysosomes. This lysosomal targeting is independent of canonical autophagy: both WT and Atg5-/- mouse embryonic fibroblasts responded similarly. Furthermore, we identify hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs), an endosomal sorting complexes required for transport (ESCORT-0) component, as a downstream target of mTORC1. Hrs requires mTORC1 activity to maintain its protein expression level. Silencing Hrs without decreasing mTORC1 activity is sufficient to target transferrin and sphingomyelin to the lysosomes. It is thus evident that the canonical recycling pathway is under the regulation of mTORC1 and likely most predominant in proliferating cells where mTORC1 is highly active.
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Affiliation(s)
- Kristin Dauner
- From the Chronic Disease Program, Ottawa Hospital Research Institute and
| | - Walaa Eid
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario K1H 8L6, Canada and
| | - Riya Raghupathy
- From the Chronic Disease Program, Ottawa Hospital Research Institute and
| | - John F Presley
- the Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
| | - Xiaohui Zha
- From the Chronic Disease Program, Ottawa Hospital Research Institute and .,Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario K1H 8L6, Canada and
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12
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Ocular Albinism Type 1 Regulates Melanogenesis in Mouse Melanocytes. Int J Mol Sci 2016; 17:ijms17101596. [PMID: 27690000 PMCID: PMC5085629 DOI: 10.3390/ijms17101596] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 09/07/2016] [Accepted: 09/13/2016] [Indexed: 12/22/2022] Open
Abstract
To investigate whether ocular albinism type 1 (OA1) is differentially expressed in the skin of mice with different coat colors and to determine its correlation with coat color establishment in mouse, the expression patterns and tissue distribution characterization of OA1 in the skin of mice with different coat colors were qualitatively and quantitatively analyzed by real-time quantitative PCR (qRT-PCR), immunofluorescence staining and Western blot. The qRT-PCR analysis revealed that OA1 mRNA was expressed in all mice skin samples tested, with the highest expression level in brown skin, a moderate expression level in black skin and the lowest expression level in gray skin. Positive OA1 protein bands were also detected in all skin samples by Western blot analysis. The relative expression levels of OA1 protein in both black and brown skin were significantly higher than that in gray skin, but there was no significant difference between black and brown mice. Immunofluorescence assays revealed that OA1 was mainly expressed in the hair follicle matrix, the inner and outer root sheath in the skin tissues with different coat colors. To get further insight into the important role of OA1 in the melanocytes’ pigmentation, we transfected the OA1 into mouse melanocytes and then detected the relative expression levels of pigmentation-related gene. Simultaneously, we tested the melanin content of melanocytes. As a result, the overexpression of OA1 significantly increased the expression levels of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), tyrosinase-related protein 1 (TRP1) and premelanosome protein (PMEL). However, the tyrosinase-related protein 2 (TRP2) level was attenuated. By contrast, the level of glycoprotein non-metastatic melanoma protein b (GPNMB) was unaffected by OA1 overexpression. Furthermore, we observed a significant increase in melanin content in mouse melanocyte transfected OA1. Therefore, we propose that OA1 may participate in the formation of coat color by regulating the level of MITF and the number, size, motility and maturation of melanosome.
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13
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Gelis L, Jovancevic N, Veitinger S, Mandal B, Arndt HD, Neuhaus EM, Hatt H. Functional Characterization of the Odorant Receptor 51E2 in Human Melanocytes. J Biol Chem 2016; 291:17772-86. [PMID: 27226631 DOI: 10.1074/jbc.m116.734517] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Indexed: 12/17/2022] Open
Abstract
Olfactory receptors, which belong to the family of G-protein-coupled receptors, are found to be ectopically expressed in non-sensory tissues mediating a variety of cellular functions. In this study we detected the olfactory receptor OR51E2 at the transcript and the protein level in human epidermal melanocytes. Stimulation of primary melanocytes with the OR51E2 ligand β-ionone significantly inhibited melanocyte proliferation. Our results further showed that β-ionone stimulates melanogenesis and dendritogenesis. Using RNA silencing and receptor antagonists, we demonstrated that OR51E2 activation elevated cytosolic Ca(2+) and cAMP, which could mediate the observed increase in melanin synthesis. Co-immunocytochemical stainings using a specific OR51E2 antibody revealed subcellular localization of the receptor in early endosomes associated with EEA-1 (early endosome antigen 1). Plasma membrane preparations showed that OR51E2 protein is present at the melanocyte cell surface. Our findings thus suggest that activation of olfactory receptor signaling by external compounds can influence melanocyte homeostasis.
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Affiliation(s)
- Lian Gelis
- From the Cell Physiology, Ruhr-University Bochum, Universitaetsstrasse 150, 44801 Bochum, Germany,
| | - Nikolina Jovancevic
- From the Cell Physiology, Ruhr-University Bochum, Universitaetsstrasse 150, 44801 Bochum, Germany
| | - Sophie Veitinger
- From the Cell Physiology, Ruhr-University Bochum, Universitaetsstrasse 150, 44801 Bochum, Germany
| | - Bhubaneswar Mandal
- Organic Chemistry I, Friedrich Schiller University, Humboldtstrasse 10, 07743 Jena, Germany. and
| | - Hans-Dieter Arndt
- Organic Chemistry I, Friedrich Schiller University, Humboldtstrasse 10, 07743 Jena, Germany. and
| | - Eva M Neuhaus
- Pharmacology and Toxicology, University Hospital Jena, Drackendorfer Strasse 1, 07747 Jena, Germany
| | - Hanns Hatt
- From the Cell Physiology, Ruhr-University Bochum, Universitaetsstrasse 150, 44801 Bochum, Germany
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14
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Sun L, Wang Z, Wu H, Liu P, Zou C, Xue X, Cao C. Role of ocular albinism type 1 (OA1) GPCR in Asian gypsy moth development and transcriptional expression of heat-shock protein genes. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2016; 126:35-41. [PMID: 26778432 DOI: 10.1016/j.pestbp.2015.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 07/01/2015] [Accepted: 07/20/2015] [Indexed: 06/05/2023]
Abstract
The ocular albinism type 1 gene, named OA1, is a coding pigment cell-specific G protein-coupled receptor exclusively localized in intracellular organelles. However, the function of OA1 in insects remains generally unknown. In the present study, we explore for the first time the function of LdOA1 in the Asian gypsy moth, Lymantria dispar. To identify the function of LdOA1 gene in the development and growth of the Asian gypsy moth, the LdOA1 gene in third instar larvae was knocked down by RNAi. Compared with the controls, the knockdown of LdOA1 increased larval mortality but did not significantly affect their utilization of nutrition. Moreover, LdOA1 was stably transformed into the third chromosome of Drosophila melanogaster. The LdOA1 gene in the transformed D. melanogaster modulated the expression of heat-shock protein (hsp) and increased the expression of hsp genes under deltamethrin stress, which indicates that LdOA1 is involved in the regulation of hsp gene expression. These results deepen our understanding of the molecular function of OA1 in insects.
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Affiliation(s)
- LiLi Sun
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - ZhiYing Wang
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - HongQu Wu
- Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Peng Liu
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - ChuanShan Zou
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - XuTing Xue
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - ChuanWang Cao
- School of Forestry, Northeast Forestry University, Harbin 150040, China.
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15
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Jean-Charles PY, Snyder JC, Shenoy SK. Chapter One - Ubiquitination and Deubiquitination of G Protein-Coupled Receptors. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 141:1-55. [PMID: 27378754 DOI: 10.1016/bs.pmbts.2016.05.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The seven-transmembrane containing G protein-coupled receptors (GPCRs) constitute the largest family of cell-surface receptors. Transmembrane signaling by GPCRs is fundamental to many aspects of physiology including vision, olfaction, cardiovascular, and reproductive functions as well as pain, behavior and psychomotor responses. The duration and magnitude of signal transduction is tightly controlled by a series of coordinated trafficking events that regulate the cell-surface expression of GPCRs at the plasma membrane. Moreover, the intracellular trafficking profiles of GPCRs can correlate with the signaling efficacy and efficiency triggered by the extracellular stimuli that activate GPCRs. Of the various molecular mechanisms that impart selectivity, sensitivity and strength of transmembrane signaling, ubiquitination of the receptor protein plays an important role because it defines both trafficking and signaling properties of the activated GPCR. Ubiquitination of proteins was originally discovered in the context of lysosome-independent degradation of cytosolic proteins by the 26S proteasome; however a large body of work suggests that ubiquitination also orchestrates the downregulation of membrane proteins in the lysosomes. In the case of GPCRs, such ubiquitin-mediated lysosomal degradation engenders long-term desensitization of transmembrane signaling. To date about 40 GPCRs are known to be ubiquitinated. For many GPCRs, ubiquitination plays a major role in postendocytic trafficking and sorting to the lysosomes. This chapter will focus on the patterns and functional roles of GPCR ubiquitination, and will describe various molecular mechanisms involved in GPCR ubiquitination.
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Affiliation(s)
- P-Y Jean-Charles
- Department of Medicine (Cardiology), Duke University Medical Center, Durham, NC, United States
| | - J C Snyder
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
| | - S K Shenoy
- Department of Medicine (Cardiology), Duke University Medical Center, Durham, NC, United States; Department of Cell Biology, Duke University Medical Center, Durham, NC, United States.
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16
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Yan R, Wang X, Huang L, Lin J, Cai W, Zhang Z. GPCRserver: an accurate and novel G protein-coupled receptor predictor. MOLECULAR BIOSYSTEMS 2015; 10:2495-504. [PMID: 25014909 DOI: 10.1039/c4mb00272e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
G protein coupled receptors (GPCRs), also known as seven-transmembrane domain receptors, pass through the cellular membrane seven times and play diverse biological roles in the cells such as signaling, transporting of molecules and cell-cell communication. In this work, we develop a web server, namely the GPCRserver, which is capable of identifying GPCRs from genomic sequences, and locating their transmembrane regions. The GPCRserver contains three modules: (1) the Trans-GPCR for the transmembrane region prediction by using sequence evolutionary profiles with the assistance of neural network training, (2) the SSEA-GPCR for identifying GPCRs from genomic data by using secondary structure element alignment, and (3) the PPA-GPCR for identifying GPCRs by using profile-to-profile alignment. Our predictor was strictly benchmarked and showed its favorable performance in the real application. The web server and stand-alone programs are publicly available at .
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Affiliation(s)
- Renxiang Yan
- Institute of Applied Genomics, School of Biological Sciences and Engineering, Fuzhou University, Fuzhou 350002, China.
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17
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Erpapazoglou Z, Walker O, Haguenauer-Tsapis R. Versatile roles of k63-linked ubiquitin chains in trafficking. Cells 2014; 3:1027-88. [PMID: 25396681 PMCID: PMC4276913 DOI: 10.3390/cells3041027] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/14/2014] [Accepted: 10/21/2014] [Indexed: 12/11/2022] Open
Abstract
Modification by Lys63-linked ubiquitin (UbK63) chains is the second most abundant form of ubiquitylation. In addition to their role in DNA repair or kinase activation, UbK63 chains interfere with multiple steps of intracellular trafficking. UbK63 chains decorate many plasma membrane proteins, providing a signal that is often, but not always, required for their internalization. In yeast, plants, worms and mammals, this same modification appears to be critical for efficient sorting to multivesicular bodies and subsequent lysosomal degradation. UbK63 chains are also one of the modifications involved in various forms of autophagy (mitophagy, xenophagy, or aggrephagy). Here, in the context of trafficking, we report recent structural studies investigating UbK63 chains assembly by various E2/E3 pairs, disassembly by deubiquitylases, and specifically recognition as sorting signals by receptors carrying Ub-binding domains, often acting in tandem. In addition, we address emerging and unanticipated roles of UbK63 chains in various recycling pathways that function by activating nucleators required for actin polymerization, as well as in the transient recruitment of signaling molecules at the plasma or ER membrane. In this review, we describe recent advances that converge to elucidate the mechanisms underlying the wealth of trafficking functions of UbK63 chains.
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Affiliation(s)
- Zoi Erpapazoglou
- Institut Jacques Monod-CNRS, UMR 7592, Université-Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France.
| | - Olivier Walker
- Institut des Sciences Analytiques, UMR5280, Université de Lyon/Université Lyon 1, 69100 Villeurbanne, France.
| | - Rosine Haguenauer-Tsapis
- Institut Jacques Monod-CNRS, UMR 7592, Université-Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France.
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18
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Rosciglione S, Thériault C, Boily MO, Paquette M, Lavoie C. Gαs regulates the post-endocytic sorting of G protein-coupled receptors. Nat Commun 2014; 5:4556. [PMID: 25089012 PMCID: PMC4846350 DOI: 10.1038/ncomms5556] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 06/30/2014] [Indexed: 12/31/2022] Open
Abstract
The role of Gαs in G protein-coupled receptor (GPCR) signalling at the cell surface is well established. Recent evidence has revealed the presence of Gαs on endosomes and its capacity to elicit GPCR-promoted signalling from this intracellular compartment. Here, we report an unconventional role for Gαs in the endocytic sorting of GPCRs to lysosomes. Cellular depletion of Gαs specifically delays the lysosomal degradation of GPCRs by disrupting the transfer of GPCRs into the intraluminal vesicles (ILVs) of multivesicular bodies. We show that Gαs interacts with GPCR-associated binding protein-1 (GASP1) and dysbindin, two key proteins that serve as linkers between GPCRs and the endosomal-sorting complex required for transport (ESCRT) machinery involved in receptor sorting into ILVs. Our findings reveal that Gαs plays a role in both GPCR signalling and trafficking pathways, providing another piece in the intertwining molecular network between these processes.
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Affiliation(s)
- Stéphanie Rosciglione
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Caroline Thériault
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Marc-Olivier Boily
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Marilène Paquette
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Christine Lavoie
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
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19
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Abstract
Live-cell imaging reveals the endolysosomal system as a complex and highly dynamic network of interacting compartments. Distinct types of endosomes are discerned by kinetic, molecular, and morphological criteria. Although none of these criteria, or combinations thereof, can capture the full complexity of the endolysosomal system, they are extremely useful for experimental purposes. Some membrane domain specializations and specific morphological characteristics can only be seen by ultrastructural analysis after preparation for electron microscopy (EM). Immuno-EM allows a further discrimination of seemingly identical compartments by their molecular makeup. In this review we provide an overview of the ultrastructural characteristics and membrane organization of endosomal compartments, along with their organizing machineries.
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Affiliation(s)
- Judith Klumperman
- Department of Cell Biology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Graça Raposo
- Institut Curie, Centre de Recherche, Paris F-75248, France Structure and Membrane Compartments CNRS UMR144, Paris F-75248, France
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20
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Bai J, Xie X, Lei Y, An G, He L, Lv X. Ocular albinism type 1-induced melanoma cell migration is mediated through the RAS/RAF/MEK/ERK signaling pathway. Mol Med Rep 2014; 10:491-5. [PMID: 24736838 DOI: 10.3892/mmr.2014.2154] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 03/04/2014] [Indexed: 11/06/2022] Open
Abstract
Malignant melanoma has the highest risk of mortality among all types of skin cancer due to its highly metastatic potential. The ocular albinism type 1 (OA1) protein is a pigment cell‑specific glycoprotein, which shares significant structural and functional features with G protein‑coupled receptors. However, the role of OA1 in melanoma has yet to be elucidated. The present study aimed to investigate whether OA1 is involved in melanoma cell migration. OA1 was found to stimulate cell migration in a dose‑dependent manner in cultured human melanoma cells. Furthermore, knockdown of OA1 using small interfering RNA was observed to significantly inhibit melanoma cell migration. In addition, the mechanism underlying OA1‑induced melanoma cell migration was investigated. Stimulation of the RAS/RAF/mitogen activated protein kinase kinase (MEK)/extracellular signal‑regulated kinase (ERK) pathway using growth factors enhanced OA1 expression and melanoma cell migration, whereas inhibition of this pathway using U0126 was observed to markedly decrease OA1 expression and the number of migrated cells. These findings indicate that OA1 is involved in melanoma cell migration and that OA1‑induced melanoma cell migration is mediated through the RAS/RAF/MEK/ERK signaling pathway. Therefore, OA1 may serve as a novel therapeutic target for melanoma.
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Affiliation(s)
- Jun Bai
- Department of Medical Oncology, Shaanxi Provincial People's Hospital, The Third Affiliated Hospital of The School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710068, P.R. China
| | - Xin Xie
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China
| | - Yun Lei
- Department of Medical Oncology, Shaanxi Provincial People's Hospital, The Third Affiliated Hospital of The School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710068, P.R. China
| | - Gaili An
- Department of Medical Oncology, Shaanxi Provincial People's Hospital, The Third Affiliated Hospital of The School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710068, P.R. China
| | - Li He
- Department of Medical Oncology, Shaanxi Provincial People's Hospital, The Third Affiliated Hospital of The School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710068, P.R. China
| | - Xiaopeng Lv
- Department of Translational Medicine, Institute of Integrated Medical Information, Xi'an, Shaanxi 710016, P.R. China
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21
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Burgoyne T, Jolly R, Martin-Martin B, Seabra MC, Piccirillo R, Schiaffino MV, Futter CE. Expression of OA1 limits the fusion of a subset of MVBs with lysosomes - a mechanism potentially involved in the initial biogenesis of melanosomes. J Cell Sci 2013; 126:5143-52. [PMID: 24006264 PMCID: PMC3828590 DOI: 10.1242/jcs.128561] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Multivesicular endosomes/bodies (MVBs) deliver proteins, such as activated EGF receptor (EGFR), to the lysosome for degradation, and, in pigmented cells, MVBs containing PMEL are an initial stage in melanosome biogenesis. The mechanisms regulating numbers and fate of different populations of MVB are unclear. Here, we focus on the role of the G-protein-coupled receptor OA1 (also known as GPR143), which is expressed exclusively in pigmented cells and mutations in which cause the most common type of ocular albinism. When exogenously expressing PMEL, HeLa cells have been shown to form MVBs resembling early stage melanosomes. To focus on the role of OA1 in the initial stages of melanosome biogenesis we take advantage of the absence of the later stages of melanosome maturation in HeLa cells to determine whether OA1 activity can regulate MVB number and fate. Expression of wild-type but not OA1 mutants carrying inactivating mutations or deletions causes MVB numbers to increase. Whereas OA1 expression has no effect on delivery of EGFR-containing MVBs to the lysosome, it inhibits the lysosomal delivery of PMEL and PMEL-containing MVBs accumulate. We propose that OA1 activity delays delivery of PMEL-containing MVBs to the lysosome to allow time for melanin synthesis and commitment to melanosome biogenesis.
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Affiliation(s)
- Thomas Burgoyne
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
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22
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Alonso V, Friedman PA. Minireview: ubiquitination-regulated G protein-coupled receptor signaling and trafficking. Mol Endocrinol 2013; 27:558-72. [PMID: 23471539 DOI: 10.1210/me.2012-1404] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are the largest and most diverse superfamily of membrane proteins and mediate most cellular responses to hormones and neurotransmitters. Posttranslational modifications are considered the main regulators of all GPCRs. In addition to phosphorylation, glycosylation, and palmitoylation, increasing evidence as reviewed here reveals that ubiquitination also regulates the magnitude and temporospatial aspects of GPCR signaling. Posttranslational protein modification by ubiquitin is a key molecular mechanism governing proteins degradation. Ubiquitination mediates the covalent conjugation of ubiquitin, a highly conserved polypeptide of 76 amino acids, to protein substrates. This process is catalyzed by 3 enzymes acting in tandem: an E1, ubiquitin-activating enzyme; an E2, ubiquitin-carrying enzyme; and an E3, ubiquitin ligase. Ubiquitination is counteracted by deubiquitinating enzymes that deconjugate ubiquitin-modified proteins and rescue the substrate from proteasomal degradation. Although ubiquitination is known to target many GPCRs for lysosomal or proteasomal degradation, emerging findings define novel roles for the basal status of ubiquitination and for rapid deubiquitination and transubiquitination controlling cell surface expression and cellular responsiveness of some GPCRs. In this review, we highlight the classical and novel roles of ubiquitin in the regulation of GPCR function, signaling, and trafficking.
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Affiliation(s)
- Verónica Alonso
- Institute of Applied Molecular Medicine, San Pablo-CEU University School of Medicine, Madrid, 28668, Spain
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23
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Watt B, van Niel G, Raposo G, Marks MS. PMEL: a pigment cell-specific model for functional amyloid formation. Pigment Cell Melanoma Res 2013; 26:300-15. [PMID: 23350640 DOI: 10.1111/pcmr.12067] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 01/15/2013] [Indexed: 12/15/2022]
Abstract
PMEL is a pigment cell-specific protein responsible for the formation of fibrillar sheets within the pigment organelle, the melanosome. The fibrillar sheets serve as a template upon which melanins polymerize as they are synthesized. The PMEL fibrils are required for optimal pigment cell function, as animals that either lack PMEL expression or express mutant PMEL variants show varying degrees of hypopigmentation and pigment cell inviability. The PMEL fibrils have biophysical properties of amyloid, a protein fold that is frequently associated with neurodegenerative and other diseases. However, PMEL is one of a growing number of non-pathogenic amyloid proteins that contribute to the function of the cell and/or organism that produces them. Understanding how PMEL generates amyloid in a non-pathogenic manner might provide insights into how to avoid toxicity due to pathological amyloid formation. In this review, we summarize and reconcile data concerning the fate of PMEL from its site of synthesis in the endoplasmic reticulum to newly formed melanosomes and the role of distinct PMEL subdomains in trafficking and amyloid fibril formation. We then discuss how its progression through the secretory pathway into the endosomal system might allow for the regulated and non-toxic conversion of PMEL into an ordered amyloid polymer.
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Affiliation(s)
- Brenda Watt
- Department of Pathology and Laboratory Medicine, Department of Physiology, and Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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24
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Sitaram A, Marks MS. Mechanisms of protein delivery to melanosomes in pigment cells. Physiology (Bethesda) 2012; 27:85-99. [PMID: 22505665 DOI: 10.1152/physiol.00043.2011] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vertebrate pigment cells in the eye and skin are useful models for cell types that use specialized endosomal trafficking pathways to partition cargo proteins to unique lysosome-related organelles such as melanosomes. This review describes current models of protein trafficking required for melanosome biogenesis in mammalian melanocytes.
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Affiliation(s)
- Anand Sitaram
- Cell and Molecular Biology Graduate Group, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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25
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Erpapazoglou Z, Dhaoui M, Pantazopoulou M, Giordano F, Mari M, Léon S, Raposo G, Reggiori F, Haguenauer-Tsapis R. A dual role for K63-linked ubiquitin chains in multivesicular body biogenesis and cargo sorting. Mol Biol Cell 2012; 23:2170-83. [PMID: 22493318 PMCID: PMC3364180 DOI: 10.1091/mbc.e11-10-0891] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In yeast, the sorting of transmembrane proteins into the multivesicular body (MVB) internal vesicles requires their ubiquitylation by the ubiquitin ligase Rsp5. This allows their recognition by the ubiquitin-binding domains (UBDs) of several endosomal sorting complex required for transport (ESCRT) subunits. K63-linked ubiquitin (K63Ub) chains decorate several MVB cargoes, and accordingly we show that they localize prominently to the class E compartment, which accumulates ubiquitylated cargoes in cells lacking ESCRT components. Conversely, yeast cells unable to generate K63Ub chains displayed MVB sorting defects. These properties are conserved among eukaryotes, as the mammalian melanosomal MVB cargo MART-1 is modified by K63Ub chains and partly missorted when the genesis of these chains is inhibited. We show that all yeast UBD-containing ESCRT proteins undergo ubiquitylation and deubiquitylation, some being modified through the opposing activities of Rsp5 and the ubiquitin isopeptidase Ubp2, which are known to assemble and disassemble preferentially K63Ub chains, respectively. A failure to generate K63Ub chains in yeast leads to an MVB ultrastructure alteration. Our work thus unravels a double function of K63Ub chains in cargo sorting and MVB biogenesis.
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Affiliation(s)
- Zoi Erpapazoglou
- Institut Jacques Monod, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7592, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
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26
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Haddad A, Flint-Ashtamker G, Minzel W, Sood R, Rimon G, Barki-Harrington L. Prostaglandin EP1 receptor down-regulates expression of cyclooxygenase-2 by facilitating its proteasomal degradation. J Biol Chem 2012; 287:17214-17223. [PMID: 22474323 DOI: 10.1074/jbc.m111.304220] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The enzyme cyclooxygenase-2 (COX-2) is rapidly and transiently up-regulated by a large variety of signals and implicated in pathologies such as inflammation and tumorigenesis. Although many signals cause COX-2 up-regulation, much less is known about mechanisms that actively down-regulate its expression. Here we show that the G protein-coupled receptor prostaglandin E(1) (EP(1)) reduces the expression of COX-2 in a concentration-dependent manner through a mechanism that does not require receptor activation. The reduction in COX-2 protein is not due to decreased protein synthesis and occurs because of enhancement of substrate-independent COX-2 proteolysis. Although EP(1) does not interfere with the entry of COX-2 into the endoplasmic reticulum-associated degradation cascade, it facilitates COX-2 ubiquitination through complex formation. Blockade of proteasomal activity results in degradation of the receptor and concomitant recovery in the expression of COX-2, suggesting that EP(1) may scaffold an unknown E3 ligase that ubiquitinates COX-2. These findings propose a new role for the EP(1) receptor in resolving inflammation through down-regulation of COX-2.
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Affiliation(s)
- Ariz Haddad
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel
| | - Galit Flint-Ashtamker
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel
| | - Waleed Minzel
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel
| | - Rapita Sood
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel
| | - Gilad Rimon
- Department of Clinical Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Liza Barki-Harrington
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel.
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