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Jain L, Vickers MH, Jacob B, Middleditch MJ, Chudakova DA, Ganley ARD, O'Sullivan JM, Perry JK. The growth hormone receptor interacts with transcriptional regulator HMGN1 upon GH-induced nuclear translocation. J Cell Commun Signal 2023; 17:925-937. [PMID: 37043098 PMCID: PMC10409943 DOI: 10.1007/s12079-023-00741-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 03/15/2023] [Indexed: 04/13/2023] Open
Abstract
Growth hormone (GH) actions are mediated through binding to its cell-surface receptor, the GH receptor (GHR), with consequent activation of downstream signalling. However, nuclear GHR localisation has also been observed and is associated with increased cancer cell proliferation. Here we investigated the functional implications of nuclear translocation of the GHR in the human endometrial cancer cell-line, RL95-2, and human mammary epithelial cell-line, MCF-10A. We found that following GH treatment, the GHR rapidly translocates to the nucleus, with maximal localisation at 5-10 min. Combined immunoprecipitation-mass spectrometry analysis of RL95-2 whole cell lysates identified 40 novel GHR binding partners, including the transcriptional regulator, HMGN1. Moreover, microarray analysis demonstrated that the gene targets of HMGN1 were differentially expressed following GH treatment, and co-immunoprecipitation showed that HMGN1 associates with the GHR in the nucleus. Therefore, our results suggest that GHR nuclear translocation might mediate GH actions via interaction with chromatin factors that then drive changes in specific downstream transcriptional programs.
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Affiliation(s)
- Lekha Jain
- The Liggins Institute, University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, 1142, New Zealand
| | - Mark H Vickers
- The Liggins Institute, University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, 1142, New Zealand
| | - Bincy Jacob
- Faculty of Science, University of Auckland, Auckland, New Zealand
| | | | - Daria A Chudakova
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Austen R D Ganley
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Justin M O'Sullivan
- The Liggins Institute, University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, 1142, New Zealand.
| | - Jo K Perry
- The Liggins Institute, University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, 1142, New Zealand.
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Chhabra Y, Lee CMM, Müller AF, Brooks AJ. GHR signalling: Receptor activation and degradation mechanisms. Mol Cell Endocrinol 2021; 520:111075. [PMID: 33181235 DOI: 10.1016/j.mce.2020.111075] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 12/21/2022]
Abstract
Growth hormone (GH) actions via initiating cell signalling through the GH receptor (GHR) are important for many physiological processes, in addition to its well-known role in regulating growth. The activation of JAK-STAT signalling by GH is well characterized, however knowledge on GH activation of SRC family kinases (SFKs) is still limited. In this review we summarise the collective knowledge on the activation, regulation, and downstream signalling of GHR. We highlight studies on GH activation of SFKs and the important outcome of this signalling pathway with a focus on the different degradation mechanisms that can regulate GHR availability since this is an area that warrants further study considering its role in tumour progression.
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Affiliation(s)
- Yash Chhabra
- The University of Queensland Diamantina Institute, The University of Queensland, Woolloongabba, QLD, 4102, Australia; Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21231, USA
| | - Christine M M Lee
- The University of Queensland Diamantina Institute, The University of Queensland, Woolloongabba, QLD, 4102, Australia
| | - Alexandra Franziska Müller
- The University of Queensland Diamantina Institute, The University of Queensland, Woolloongabba, QLD, 4102, Australia
| | - Andrew J Brooks
- The University of Queensland Diamantina Institute, The University of Queensland, Woolloongabba, QLD, 4102, Australia.
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3
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Li R, Hui J, Luo G, Hong P, Li L, Yang Y, Zheng X, Lan H. Zinc ions increase GH signaling ability through regulation of available plasma membrane-localized GHR. J Cell Physiol 2019; 234:23388-23397. [PMID: 31173363 DOI: 10.1002/jcp.28908] [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] [Received: 04/05/2019] [Revised: 05/09/2019] [Accepted: 05/13/2019] [Indexed: 12/15/2022]
Abstract
It is well known that zinc ion (Zn2+ ) can regulate the biological activity of growth hormone (GH). However, until now, the mechanism by which Zn2+ regulates GH biological activity remains unclear. In the current study, we first performed molecular docking between Zn2+ and porcine GH (pGH) using computational biology. We then explored the effect of Zn2+ on the GH signaling ability in the cell model expressing porcine growth hormone receptor (GHR). It was found that the phosphorylation levels of Janus kinase 2, signal transducers and activators of transcription 5/3/1, and GHR increased significantly under Zn2+ treatment, indicating that Zn2+ can enhance the signaling ability of GH/GHR. On this basis, we further explored how Zn2+ regulates the biological activity of GH/GHR. The results showed that downregulation and turnover of GHR changed under Zn2+ /pGH treatment. Zn2+ enhanced the membrane residence time of pGH/GHR and delayed GHR downregulation. Further investigation showed that the internalization dynamic of pGH/GHR was changed by Zn2+ , which prolonged the residence time of pGH/GHR in the cell membrane. These factors acted together to upregulate the signaling of GH/GHR. This study lays a foundation for further exploration of the biological effects of Zn2+ on GH.
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Affiliation(s)
- Ruonan Li
- College of Animal Science and Technology, Jilin Agricultural University, Xincheng Street, Changchun, China
| | - Junnan Hui
- College of Animal Science and Technology, Jilin Agricultural University, Xincheng Street, Changchun, China
| | - Gan Luo
- College of Animal Science and Technology, Jilin Agricultural University, Xincheng Street, Changchun, China.,Department of Anesthesiology and Intensive Care, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Pan Hong
- College of Animal Science and Technology, Jilin Agricultural University, Xincheng Street, Changchun, China.,Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Lingqian Li
- College of Animal Science and Technology, Jilin Agricultural University, Xincheng Street, Changchun, China
| | - Yu Yang
- College of Animal Science and Technology, Jilin Agricultural University, Xincheng Street, Changchun, China
| | - Xin Zheng
- College of Animal Science and Technology, Jilin Agricultural University, Xincheng Street, Changchun, China
| | - Hainan Lan
- College of Animal Science and Technology, Jilin Agricultural University, Xincheng Street, Changchun, China
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4
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Hainan L, Huilin L, Khan MA, Xin Z, YuJiang Y, Hui Z, Naiquan Y. The basic route of the nuclear translocation porcine growth hormone (GH)-growth hormone receptor (GHR) complex (pGH/GHR) in porcine hepatocytes. Gen Comp Endocrinol 2018; 266:101-109. [PMID: 29890130 DOI: 10.1016/j.ygcen.2018.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 04/04/2018] [Accepted: 05/06/2018] [Indexed: 11/19/2022]
Abstract
Traditional views suggest that growth hormone and the growth hormone receptor (GH/GHR complex) exert their functions only on the plasma membrane. This paradigm, however, has been challenged by recent new findings that the GH/GHR complex could translocate into cell nuclei where they could still exhibit important physiological functions. We also reported the nuclear localization of porcine GH/GHR and their potential functions in porcine hepatocytes. However, the basic path of pGH/GHR's nuclear translocation remains unclear. Combining previous research results and our current findings, we proposed two basic routes of pGH/GHR's nuclear transportation as follows: 1) after pGH binding to GHR, pGH/GHR enters into the cytoplasm though clathrin- or caveolin-mediated endocytosis, then the pGH/GHR complex enters into early endosomes (Rab5-positive), and the endosome carries the GH/GHR complex to the endoplasmic reticulum (ER). After endosome docking on the ER, the endosome starts fission, and the pGH/GHR complex enters into the ER lumen. Then the pGH/GHR complex transports into the cytoplasm, possibly by the ERAD pathway. Subsequently, the pGH/GHR complex interacts with IMPα/β, which, in turn, mediates GH/GHR nuclear localization; 2) pGH binds with the GHR on the cell membrane and, subsequently, pGH/GHR internalizes into the cell and enters into the endosome (this endosome may belong to a class of endosomes called envelope-associated endosomes (NAE)). Then, the endosome carries the pGH/GHR to the nuclear membrane. After docking on the nuclear membrane, the pGH/GHR complex fuses with the nuclear membrane and then enters into the cell nucleus.
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Affiliation(s)
- Lan Hainan
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, PR China.
| | - Liu Huilin
- College of Life Sciences, Jilin University, Changchun 130118, PR China
| | - Muhammad Akram Khan
- Department of Pathobiology, Faculty of Veterinary and Animal Sciences, PMAS-Arid Agriculture University, Rawalpindi, Pakistan
| | - Zheng Xin
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, PR China
| | - Yang YuJiang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, PR China
| | - Zhang Hui
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, PR China
| | - Yao Naiquan
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, PR China
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5
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Grove J, Metcalf DJ, Knight AE, Wavre-Shapton ST, Sun T, Protonotarios ED, Griffin LD, Lippincott-Schwartz J, Marsh M. Flat clathrin lattices: stable features of the plasma membrane. Mol Biol Cell 2014; 25:3581-94. [PMID: 25165141 PMCID: PMC4230618 DOI: 10.1091/mbc.e14-06-1154] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Clathrin-mediated endocytosis (CME) is a fundamental property of eukaryotic cells. Classical CME proceeds via the formation of clathrin-coated pits (CCPs) at the plasma membrane, which invaginate to form clathrin-coated vesicles, a process that is well understood. However, clathrin also assembles into flat clathrin lattices (FCLs); these structures remain poorly described, and their contribution to cell biology is unclear. We used quantitative imaging to provide the first comprehensive description of FCLs and explore their influence on plasma membrane organization. Ultrastructural analysis by electron and superresolution microscopy revealed two discrete populations of clathrin structures. CCPs were typified by their sphericity, small size, and homogeneity. FCLs were planar, large, and heterogeneous and present on both the dorsal and ventral surfaces of cells. Live microscopy demonstrated that CCPs are short lived and culminate in a peak of dynamin recruitment, consistent with classical CME. In contrast, FCLs were long lived, with sustained association with dynamin. We investigated the biological relevance of FCLs using the chemokine receptor CCR5 as a model system. Agonist activation leads to sustained recruitment of CCR5 to FCLs. Quantitative molecular imaging indicated that FCLs partitioned receptors at the cell surface. Our observations suggest that FCLs provide stable platforms for the recruitment of endocytic cargo.
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Affiliation(s)
- Joe Grove
- MRC Laboratory for Molecular Cell Biology, London WC1E 6BT, United Kingdom Institute of Immunity and Transplantation, University College London, London NW3 2PF, United Kingdom
| | - Daniel J Metcalf
- Biophysics and Diagnostics, National Physical Laboratory, Teddington TW11 0LW, United Kingdom
| | - Alex E Knight
- Biophysics and Diagnostics, National Physical Laboratory, Teddington TW11 0LW, United Kingdom
| | | | - Tony Sun
- MRC Laboratory for Molecular Cell Biology, London WC1E 6BT, United Kingdom
| | | | - Lewis D Griffin
- CoMPLEX, University College London, London WC1E 6BT, United Kingdom
| | - Jennifer Lippincott-Schwartz
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Mark Marsh
- MRC Laboratory for Molecular Cell Biology, London WC1E 6BT, United Kingdom
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6
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Gilleron J, Carette D, Chevallier D, Segretain D, Pointis G. Molecular connexin partner remodeling orchestrates connexin traffic: from physiology to pathophysiology. Crit Rev Biochem Mol Biol 2012; 47:407-23. [PMID: 22551357 DOI: 10.3109/10409238.2012.683482] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Connexins, through gap junctional intercellular communication, are known to regulate many physiological functions involved in developmental processes such as cell proliferation, differentiation, migration and apoptosis. Strikingly, alterations of connexin expression and trafficking are often, if not always, associated with human developmental diseases and carcinogenesis. In this respect, disrupted trafficking dynamics and aberrant intracytoplasmic localization of connexins are considered as typical features of functionality failure leading to the pathological state. Recent findings demonstrate that interactions of connexins with numerous protein partners, which take place throughout connexin trafficking, are essential for gap junction formation, membranous stabilization and degradation. In the present study, we give an overview of the physiological molecular machinery and of the specific interactions between connexins and their partners, which are involved in connexin trafficking, and we highlight their changes in pathological situations.
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Affiliation(s)
- Jérôme Gilleron
- INSERM U 1065, University Nice Sophia Antipolis, Team 5, C3M, 151 route Saint-Antoine de Ginestière, France
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7
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da Silva Almeida AC, Strous GJ, van Rossum AGSH. βTrCP controls GH receptor degradation via two different motifs. Mol Endocrinol 2011; 26:165-77. [PMID: 22034227 DOI: 10.1210/me.2011-1211] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The physiological roles of GH are broad and include metabolism regulation and promotion of somatic growth. Therefore, the responsiveness of cells to GH must be tightly regulated. This is mainly achieved by a complex and well-controlled mechanism of GH receptor (GHR) endocytosis. GHR endocytosis occurs independently of GH and requires the ubiquitin ligase, SCF (βTrCP) that is recruited to the ubiquitin-dependent endocytosis (UbE) motif in the cytoplasmic tail of the GHR. In this study we report that, in addition to the UbE motif, a downstream degron, DSGRTS, binds to βTrCP. The WD40 residues on βTrCP involved in the interaction with this sequence are identical to the ones necessary for binding the classical motif, DSGxxS, in inhibitor of NFκB signalling, and β-catenin. Previously, we showed that this motif is not involved in GH-induced endocytosis. We show here that the DSGRTS sequence significantly contributes to GHR endocytosis/degradation in basal conditions, whereas the UbE motif is involved both in basal and GH-induced conditions. These findings explain the high rate of GHR degradation under basal conditions, which is important for regulating the responsiveness of cells to GH.
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Affiliation(s)
- Ana C da Silva Almeida
- Department of Cell Biology and Institute of Biomembranes, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
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8
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Mercanti V, Marchetti A, Lelong E, Perez F, Orci L, Cosson P. Transmembrane domains control exclusion of membrane proteins from clathrin-coated pits. J Cell Sci 2010; 123:3329-35. [DOI: 10.1242/jcs.073031] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Efficient sorting of proteins is essential to allow transport between intracellular compartments while maintaining their specific composition. During endocytosis, membrane proteins can be concentrated in endocytic vesicles by specific interactions between their cytoplasmic domains and cytosolic coat proteins. It is, however, unclear whether they can be excluded from transport vesicles and what the determinants for this sorting could be. Here, we show that in the absence of cytosolic sorting signals, transmembrane domains control the access of surface proteins to endosomal compartments. They act in particular by determining the degree of exclusion of membrane proteins from endocytic clathrin-coated vesicles. When cytosolic endocytosis signals are present, it is the combination of cytosolic and transmembrane determinants that ultimately controls the efficiency with which a given transmembrane protein is endocytosed.
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Affiliation(s)
- Valentina Mercanti
- Centre Médical Universitaire, Département de Physiologie Cellulaire et Métabolisme, 1, rue Michel Servet, CH1211 Geneva 4, Switzerland
- UMR 144 CNRS, Institut Curie, 12 rue Lhomond, 75005 Paris, France
| | - Anna Marchetti
- Centre Médical Universitaire, Département de Physiologie Cellulaire et Métabolisme, 1, rue Michel Servet, CH1211 Geneva 4, Switzerland
| | - Emmanuelle Lelong
- Centre Médical Universitaire, Département de Physiologie Cellulaire et Métabolisme, 1, rue Michel Servet, CH1211 Geneva 4, Switzerland
| | - Franck Perez
- UMR 144 CNRS, Institut Curie, 12 rue Lhomond, 75005 Paris, France
| | - Lelio Orci
- Centre Médical Universitaire, Département de Physiologie Cellulaire et Métabolisme, 1, rue Michel Servet, CH1211 Geneva 4, Switzerland
| | - Pierre Cosson
- Centre Médical Universitaire, Département de Physiologie Cellulaire et Métabolisme, 1, rue Michel Servet, CH1211 Geneva 4, Switzerland
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9
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Shepard BD, Fernandez DJ, Tuma PL. Alcohol consumption impairs hepatic protein trafficking: mechanisms and consequences. GENES AND NUTRITION 2009; 5:129-40. [PMID: 19890673 DOI: 10.1007/s12263-009-0156-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 10/11/2009] [Indexed: 12/20/2022]
Abstract
Alcoholic liver disease is a major biomedical health concern in the United States. Despite considerable research efforts aimed at understanding the progression of the disease, the specific mechanisms leading to alcohol-induced damage remain elusive. Numerous proteins are known to have alcohol-induced alterations in their dynamics. Defining these defects in protein trafficking is an active area of research. In general, two trafficking pathways are affected: transport of newly synthesized secretory or membrane glycoproteins from the Golgi to the basolateral membrane and clathrin-mediated endocytosis from the sinusoidal surface. Both impaired secretion and internalization require ethanol metabolism and are likely mediated by acetaldehyde. Although the mechanisms by which ethanol exposure impairs protein trafficking are not fully understood, recent work implicates alcohol-induced modifications on tubulin or components of the clathrin machinery as potential mediators. Furthermore, the physiological ramifications of impaired protein trafficking are not fully understood. In this review, we will list and discuss the proteins whose trafficking patterns are known to be impaired by ethanol exposure. We will then describe what is known about the possible mechanisms leading to impaired protein trafficking and how disrupted protein trafficking alters liver function and may explain clinical features of the alcoholic patient.
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Affiliation(s)
- Blythe D Shepard
- Department of Biology, The Catholic University of America, 620 Michigan Avenue, NE, Washington, DC, 20064, USA
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10
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Frank SJ, Fuchs SY. Modulation of growth hormone receptor abundance and function: roles for the ubiquitin-proteasome system. Biochim Biophys Acta Mol Basis Dis 2008; 1782:785-94. [PMID: 18586085 DOI: 10.1016/j.bbadis.2008.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2008] [Revised: 05/27/2008] [Accepted: 06/03/2008] [Indexed: 10/22/2022]
Abstract
Growth hormone plays an important role in regulating numerous functions in vertebrates. Several pathways that negatively regulate the magnitude and duration of its signaling (including expression of tyrosine phosphatases, SOCS and PIAS proteins) are shared between signaling induced by growth hormone itself and by other cytokines. Here we overview downregulation of the growth hormone receptor as the most specific and potent mechanism of restricting cellular responses to growth hormone and analyze the role of several proteolytic systems and, specifically, ubiquitin-dependent pathways in this regulation.
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Affiliation(s)
- Stuart J Frank
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA.
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11
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Hanyaloglu AC, von Zastrow M. Regulation of GPCRs by endocytic membrane trafficking and its potential implications. Annu Rev Pharmacol Toxicol 2008; 48:537-68. [PMID: 18184106 DOI: 10.1146/annurev.pharmtox.48.113006.094830] [Citation(s) in RCA: 447] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The endocytic pathway tightly controls the activity of G protein-coupled receptors (GPCRs). Ligand-induced endocytosis can drive receptors into divergent lysosomal and recycling pathways, producing essentially opposite effects on the strength and duration of cellular signaling via heterotrimeric G proteins, and may also promote distinct signaling events from intracellular membranes. This chapter reviews recent developments toward understanding the molecular machinery and functional implications of GPCR sorting in the endocytic pathway, focusing on mammalian GPCRs whose ligand-induced endocytosis is mediated primarily by clathrin-coated pits. Lysosomal sorting of a number of GPCRs occurs via a highly conserved mechanism requiring covalent tagging of receptors with ubiquitin. There is increasing evidence that additional, noncovalent mechanisms control the sorting of endocytosed GPCRs to lysosomes in mammalian cells. Recycling of several GPCRs to the plasma membrane is also specifically sorted, via a mechanism requiring both receptor-specific and shared sorting proteins. The current data reveal an unprecedented degree of specificity and plasticity in the cellular regulation of mammalian GPCRs by endocytic membrane trafficking. These developments have fundamental implications for GPCR pharmacology, and suggest new mechanisms that could be exploited in GPCR-directed pharmacotherapy.
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Affiliation(s)
- Aylin C Hanyaloglu
- Institute of Reproductive Biology and Development, Imperial College London, Hammersmith Campus, London, United Kingdom
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12
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van den Eijnden MJM, Lahaye LL, Strous GJ. Disulfide bonds determine growth hormone receptor folding, dimerisation and ligand binding. J Cell Sci 2006; 119:3078-86. [PMID: 16820415 DOI: 10.1242/jcs.03036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The growth hormone receptor contains seven cysteine residues in its extracellular domain. The six in the growth hormone binding domain form disulfide bonds, and help the receptor to gain its correct three-dimensional structure. In this study we replaced the cysteine for serine and alanine residues and investigated their role in growth hormone receptor folding, dimerisation and signal transduction. Folding and growth hormone binding capacity of the wild-type growth hormone receptor require less than two minutes for completion. Although less efficient, all mutant receptors arrive at the cell surface as pre-formed dimers. Disulfide bond C38-C48 is important for efficient maturation. The middle disulfide-bond, C83-C94, is important for ligand binding. Removing disulfide bond C108-C122 has little effect without affecting signalling. When two or all disulfide bonds are changed, ligand binding and activation are blocked. Dimerisation is delayed when all disulfide bonds are destroyed.
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Affiliation(s)
- Monique J M van den Eijnden
- Department of Cell Biology, Institute of Biomembranes, University Medical Center Utrecht, Heidelberglaan 100, G02.525, 3584 CX Utrecht, The Netherlands
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13
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Landsman T, Waxman DJ. Role of the cytokine-induced SH2 domain-containing protein CIS in growth hormone receptor internalization. J Biol Chem 2005; 280:37471-80. [PMID: 16154995 DOI: 10.1074/jbc.m504125200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cytokine-inducible SH2 domain-containing protein CIS inhibits signaling from the growth hormone (GH) receptor (GHR) to STAT5b by a proteasome-dependent mechanism. Here, we used the GH-responsive rat liver cell line CWSV-1 to investigate the role of CIS and the proteasome in GH-induced GHR internalization. Cell-surface GHR localization and internalization were monitored in GH-stimulated cells by confocal immunofluorescence microscopy using an antibody directed against the GHR extracellular domain. In GH naïve cells, GHR was detected in small, randomly distributed granules on the cell surface and in the cytoplasm, with accumulation in the perinuclear area. GH treatment induced a rapid (within 5 min) internalization of GH.GHR complexes, which coincided with the onset of GHR tyrosine phosphorylation and the appearance in the cytosol of distinct granular structures containing internalized GH. GHR signaling to STAT5b continued for approximately 30-40 min, however, indicating that GHR signaling and deactivation of the GH.GHR complex both proceed from an intracellular compartment. The internalization of GH and GHR was inhibited by CIS-R107K, a dominant-negative SH2 domain mutant of CIS, and by the proteasome inhibitors MG132 and epoxomicin, which prolong GHR signaling to STAT5b. GH pulse-chase studies established that the internalized GH.GHR complexes did not recycle back to the cell surface in significant amounts under these conditions. Given the established specificity of CIS-R107K for blocking the GHR signaling inhibitory actions of CIS, but not those of other SOCS/CIS family members, these findings implicate CIS and the proteasome in the control of GHR internalization following receptor activation and suggest that CIS-dependent receptor internalization is a prerequisite for efficient termination of GHR signaling.
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Affiliation(s)
- Tanya Landsman
- Division of Cell and Molecular Biology, Department of Biology, Boston University, MA 02215, USA
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14
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Dupré S, Urban-Grimal D, Haguenauer-Tsapis R. Ubiquitin and endocytic internalization in yeast and animal cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1695:89-111. [PMID: 15571811 DOI: 10.1016/j.bbamcr.2004.09.024] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Endocytosis is involved in a wide variety of cellular processes, and the internalization step of endocytosis has been extensively studied in both lower and higher eukaryotic cells. Studies in mammalian cells have described several endocytic pathways, with the main emphasis on clathrin-dependent endocytosis. Genetic studies in yeast have underlined the critical role of actin and actin-binding proteins, lipid modification, and the ubiquitin conjugation system. The combined results of studies of endocytosis in higher and lower eukaryotic cells reveal an interesting interplay in the two systems, including a crucial role for ubiquitin-associated events. The ubiquitylation of yeast cell-surface proteins clearly acts as a signal triggering their internalization. Mammalian cells display variations on the common theme of ubiquitin-linked endocytosis, according to the cell-surface protein considered. Many plasma membrane channels, transporters and receptors undergo cell-surface ubiquitylation, required for the internalization or later endocytic steps of some cell-surface proteins, whereas for others, internalization involves interaction with the ubiquitin conjugation system or with ancillary proteins, which are themselves ubiquitylated. Epsins and Eps15 (or Eps15 homologs), are commonly involved in the process of endocytosis in all eukaryotes, their critical role in this process stemming from their capacity to bind ubiquitin, and to undergo ubiquitylation.
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Affiliation(s)
- S Dupré
- Institut Jacques Monod-CNRS Universités Paris VI and Paris VII, 2 place Jussieu 75005 Paris, France
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15
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Signoret N, Hewlett L, Wavre S, Pelchen-Matthews A, Oppermann M, Marsh M. Agonist-induced endocytosis of CC chemokine receptor 5 is clathrin dependent. Mol Biol Cell 2004; 16:902-17. [PMID: 15591129 PMCID: PMC545921 DOI: 10.1091/mbc.e04-08-0687] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The signaling activity of several chemokine receptors, including CC chemokine receptor 5 (CCR5), is in part controlled by their internalization, recycling, and/or degradation. For CCR5, agonists such as the chemokine CCL5 induce internalization into early endosomes containing the transferrin receptor, a marker for clathrin-dependent endocytosis, but it has been suggested that CCR5 may also follow clathrin-independent routes of internalization. Here, we present a detailed analysis of the role of clathrin in chemokine-induced CCR5 internalization. Using CCR5-transfected cell lines, immunofluorescence, and electron microscopy, we demonstrate that CCL5 causes the rapid redistribution of scattered cell surface CCR5 into large clusters that are associated with flat clathrin lattices. Invaginated clathrin-coated pits could be seen at the edge of these lattices and, in CCL5-treated cells, these pits contain CCR5. Receptors internalized via clathrin-coated vesicles follow the clathrin-mediated endocytic pathway, and depletion of clathrin with small interfering RNAs inhibits CCL5-induced CCR5 internalization. We found no evidence for CCR5 association with caveolae during agonist-induced internalization. However, sequestration of cholesterol with filipin interferes with agonist binding to CCR5, suggesting that cholesterol and/or lipid raft domains play some role in the events required for CCR5 activation before internalization.
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Affiliation(s)
- Nathalie Signoret
- Cell Biology Unit, Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
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16
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Abstract
Proteins that make, consume, and bind to phosphoinositides are important for constitutive membrane traffic. Different phosphoinositides are concentrated in different parts of the central vacuolar pathway, with phosphatidylinositol 4-phosphate predominate on Golgi, phosphatidylinositol 4,5-bisphosphate predominate at the plasma membrane, phosphatidylinositol 3-phosphate the major phosphoinositide on early endosomes, and phosphatidylinositol 3,5-bisphosphate found on late endocytic organelles. This spatial segregation may be the mechanism by which the direction of membrane traffic is controlled. Phosphoinositides increase the affinity of membranes for peripheral membrane proteins that function for sorting protein cargo or for the docking and fusion of transport vesicles. This implies that constitutive membrane traffic may be regulated by the mechanisms that control the activity of the enzymes that produce and consume phosphoinositides. Although the lipid kinases and phosphatases that function in constitutive membrane traffic are beginning to be identified, their regulation is poorly understood.
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Affiliation(s)
- Michael G Roth
- Dept. of Biochemistry, Univ. of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, TX 75390-9038, USA.
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Strous GJ, dos Santos CA, Gent J, Govers R, Sachse M, Schantl J, van Kerkhof P. Ubiquitin system-dependent regulation of growth hormone receptor signal transduction. Curr Top Microbiol Immunol 2004; 286:81-118. [PMID: 15645711 DOI: 10.1007/978-3-540-69494-6_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The growth hormone (GH) receptor is a key regulator of cellular metabolism. Unlike most growth factor receptors, its downregulation is not initiated by its ligand. Like many growth factor receptors, specific molecular mechanisms guarantee that a receptor can signal only once in its lifetime. Three features render the GH receptor unique: (a) an active ubiquitination system is required for both uptake (endocytosis) and degradation in the lysosomes; (b) uptake of the receptor is a continuous process, independent of both GH binding and Jak2 signal transduction; (c) only the cell surface expression of dimerised GH receptors is controlled by the ubiquitin system. This system enables two independent regulatory mechanisms for the endocrinology of the GH/GHR axis: the pulsatile secretion of GH by the pituitary and the GH sensitivity of individual cells of the body by the effects of the ubiquitin system on GH receptor availability.
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Affiliation(s)
- G J Strous
- Department of Cell Biology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands.
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18
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Khor R, McElroy LJ, Whittaker GR. The Ubiquitin-Vacuolar Protein Sorting System is Selectively Required During Entry of Influenza Virus into Host Cells. Traffic 2003; 4:857-68. [PMID: 14617349 DOI: 10.1046/j.1398-9219.2003.0140.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Influenza virus enters cells by endocytosis, and requires the low pH of the late endosome for successful infection. Here, we investigated the requirements for sorting into the multivesicular body pathway of endocytosis. We show that treatment of host cells with the proteasome inhibitors MG132 and lactacystin directly affects the early stages of virus replication. Unlike other viruses, such as retroviruses, influenza virus budding was not affected. The requirement for proteasome function was not shared by two other pH-dependent viruses: Semliki Forest virus and vesicular stomatitis virus. With MG132 treatment, incoming influenza viruses were retained in endosomes that partially colocalized with mannose 6-phosphate receptor, but not with classical markers of early or late endosomes. Colocalization was also observed with Rme-1, which is part of the recycling pathway of endocytosis. In addition, influenza virus entry was dependent on the vacuolar protein sorting pathway, as over-expression of dominant-negative hVPS4 caused arrest of viruses in endosome-like populations that partially colocalized with the hVPS4 protein. Overall, we conclude that influenza virus selectively requires the ubiquitin/vacuolar protein sorting pathway for entry into host cells, and that it must communicate with a specific cellular machinery for intracellular sorting during the initial phase of virus infection.
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Affiliation(s)
- Rebecca Khor
- Department of Microbiology & Immunology, Cornell University, Ithaca NY 14853, USA
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19
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Mihalik B, Gáborik Z, Várnai P, Clark AJL, Catt KJ, Hunyady L. Endocytosis of the AT1A angiotensin receptor is independent of ubiquitylation of its cytoplasmic serine/threonine-rich region. Int J Biochem Cell Biol 2003; 35:992-1002. [PMID: 12676183 DOI: 10.1016/s1357-2725(02)00277-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Agonist-induced internalisation of the rat type 1A (AT(1A)) angiotensin II receptor is associated with phosphorylation of a serine/threonine-rich region in its cytoplasmic tail. In yeast, hyperphosphorylation of the alpha-factor pheromone receptor regulates endocytosis of the receptor by facilitating the monoubiquitylation of its cytoplasmic tail on lysine residues. The role of receptor ubiquitylation in AT(1A) receptor internalisation was evaluated by deletion or replacement of lysine residues in its agonist-sensitive serine/threonine-rich region. Expression of such receptor mutants in CHO cells showed that these modifications had no detectable effect on the angiotensin II-induced endocytosis of the AT(1A) receptor. Furthermore, fusion of ubiquitin in-frame to an internalisation-deficient AT(1A) receptor mutant with a truncated carboxyl-terminal tail did not restore the endocytosis of the resulting chimeric receptor. No impairment of receptor internalisation was observed after substitution of all lysine residues in the serine/threonine-rich region at saturating angiotensin II concentrations, where endocytosis occurs by a beta-arrestin and dynamin independent mechanism. Taken together, these data demonstrate that ubiquitylation of the cytoplasmic serine/threonine-rich region of the AT(1A) receptor on lysine residues is not required for its agonist-induced internalisation, and suggest that endocytosis of mammalian G protein-coupled receptors (GPCRs) occurs by a different mechanism than that of yeast GPCRs.
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Affiliation(s)
- Balázs Mihalik
- Department of Physiology, Faculty of Medicine, Semmelweis University, P.O. Box 259, H-1444 Budapest, Hungary
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Gent J, Van Den Eijnden M, Van Kerkhof P, Strous GJ. Dimerization and signal transduction of the growth hormone receptor. Mol Endocrinol 2003; 17:967-75. [PMID: 12576487 DOI: 10.1210/me.2002-0261] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
GH binding to cell surface-localized GH receptors (GHRs) induces a conformational change of the dimerized receptors, resulting in activation of Janus kinase 2 and downstream signaling pathways. Interactions between the extracellular subdomain 2 of adjacent GHR polypeptides result in a 500-A2 contact interface, which has previously been suggested to stabilize the GH-(GHR)2 complex. In this study, we investigated further the role of subdomain 2 in GHR function. Amino acids that participate in (e.g. aspartic acid 152, tyrosine 200, or serine 201) or lie close to (e.g. asparagine 143 or cysteine 241) the contact interface were mutated in rabbit GHR. Surprisingly, none of the mutations affected GHR dimerization, as demonstrated by coimmunoprecipitation of a truncated, epitope-tagged GHR. However, signal transduction of GHR(D152H), GHR(Y200D), and GHR(S201K) mutants was precluded. More insight into the molecular mechanism of the signaling defect was obtained when we examined the effect of the mutations on the integrity of the GH-(GHR)2 complex in a protease-protection assay. In contrast to wild-type GHR, GHR(N143K), and GHR(C241S), the GHR(D152H), GHR(Y200D), and GHR(S201K) mutants were not protected against protease digestion by GH, indicating that a structural change is prevented. Together, we provide new evidence for a critical role of aspartic acid 152, tyrosine 200, and serine 201 of the GHR contact interface in the GH-induced conformational change to a signaling-competent complex rather than in GHR dimerization.
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Affiliation(s)
- Jürgen Gent
- Department of Cell Biology, University Medical Center Utrecht, The Netherlands
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21
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Gent J, van Kerkhof P, Roza M, Bu G, Strous GJ. Ligand-independent growth hormone receptor dimerization occurs in the endoplasmic reticulum and is required for ubiquitin system-dependent endocytosis. Proc Natl Acad Sci U S A 2002; 99:9858-63. [PMID: 12105275 PMCID: PMC125043 DOI: 10.1073/pnas.152294299] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The regulatory effect of growth hormone (GH) on its target cells is mediated via the GH receptor (GHR). GH binding to the GHR results in the formation of a GH-(GHR)(2) complex and the initiation of signal transduction cascades via the activation of the tyrosine kinase JAK2. Subsequent endocytosis and transport to the lysosome of the ligand-receptor complex is regulated via the ubiquitin system and requires the presence of an intact ubiquitin-dependent endocytosis (UbE) motif in the cytosolic tail of the GHR. Recently, the model of ligand-induced receptor dimerization has been challenged. In this study, ligand-independent GHR dimerization is demonstrated in the endoplasmic reticulum and at the cell surface by coimmunoprecipitation of an epitope-tagged truncated GHR with wild-type GHR. In addition, evidence is provided that the extracellular domain of the GHR is not required to maintain this interaction. Internalization of a chimeric receptor, which fails to dimerize, is independent of an intact UbE-motif. Therefore, we postulate that dimerization of GHR molecules is required for ubiquitin system-dependent endocytosis.
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Affiliation(s)
- Jürgen Gent
- Department of Cell Biology and Institute of Biomembranes, University Medical Center, 3584 CX, Utrecht, The Netherlands
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22
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Sachse M, Urbé S, Oorschot V, Strous GJ, Klumperman J. Bilayered clathrin coats on endosomal vacuoles are involved in protein sorting toward lysosomes. Mol Biol Cell 2002; 13:1313-28. [PMID: 11950941 PMCID: PMC102271 DOI: 10.1091/mbc.01-10-0525] [Citation(s) in RCA: 270] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In many cells endosomal vacuoles show clathrin coats of which the function is unknown. Herein, we show that this coat is predominantly present on early endosomes and has a characteristic bilayered appearance in the electron microscope. By immunoelectron microscopy we show that the coat contains clathrin heavy as well as light chain, but lacks the adaptor complexes AP1, AP2, and AP3, by which it differs from clathrin coats on endocytic vesicles and recycling endosomes. The coat is insensitive to short incubations with brefeldin A, but disappears in the presence of the phosphatidylinositol 3-kinase inhibitor wortmannin. No association of endosomal coated areas with tracks of tubulin or actin was found. By quantitative immunoelectron microscopy, we found that the lysosomal-targeted receptors for growth hormone (GHR) and epidermal growth factor are concentrated in the coated membrane areas, whereas the recycling transferrin receptor is not. In addition, we found that the proteasomal inhibitor MG 132 induces a redistribution of a truncated GHR (GHR-369) toward recycling vesicles, which coincided with a redistribution of endosomal vacuole-associated GHR-369 to the noncoated areas of the limiting membrane. Together, these data suggest a role for the bilayered clathrin coat on vacuolar endosomes in targeting of proteins to lysosomes.
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Affiliation(s)
- Martin Sachse
- Department of Cell Biology, University Medical Center Utrecht and Institute of Biomembranes, 3584 CX Utrecht, The Netherlands
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