1
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Kioumourtzoglou D, Black HL, Al Tobi M, Livingstone R, Petrie JR, Boyle JG, Gould GW, Bryant NJ. Phosphorylation of Syntaxin 4 by the Insulin Receptor Drives Exocytic SNARE Complex Formation to Deliver GLUT4 to the Cell Surface. Biomolecules 2023; 13:1738. [PMID: 38136609 PMCID: PMC10741561 DOI: 10.3390/biom13121738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/24/2023] [Accepted: 11/29/2023] [Indexed: 12/24/2023] Open
Abstract
A major consequence of insulin binding its receptor on fat and muscle cells is the stimulation of glucose transport into these tissues. This is achieved through an increase in the exocytic trafficking rate of the facilitative glucose transporter GLUT4 from intracellular stores to the cell surface. Delivery of GLUT4 to the cell surface requires the formation of functional SNARE complexes containing Syntaxin 4, SNAP23, and VAMP2. Insulin stimulates the formation of these complexes and concomitantly causes phosphorylation of Syntaxin 4. Here, we use a combination of biochemistry and cell biological approaches to provide a mechanistic link between these observations. We present data to support the hypothesis that Tyr-115 and Tyr-251 of Syntaxin 4 are direct substrates of activated insulin receptors, and that these residues modulate the protein's conformation and thus regulate the rate at which Syntaxin 4 forms SNARE complexes that deliver GLUT4 to the cell surface. This report provides molecular details on how the cell regulates SNARE-mediated membrane traffic in response to an external stimulus.
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Affiliation(s)
| | - Hannah L. Black
- Department of Biology, University of York, Heslington YO10 5DD, UK; (D.K.)
| | - Mohammed Al Tobi
- Institute of Molecular Cell and Systems Biology, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK; (M.A.T.)
| | - Rachel Livingstone
- Institute of Molecular Cell and Systems Biology, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK; (M.A.T.)
| | - John R. Petrie
- Institute of Cardiovascular and Medical Sciences, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - James G. Boyle
- School of Medicine, Dentistry & Nursing, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK;
| | - Gwyn W. Gould
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 ORE, UK
| | - Nia J. Bryant
- Department of Biology, University of York, Heslington YO10 5DD, UK; (D.K.)
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2
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Laiman J, Hsu YJ, Loh J, Tang WC, Chuang MC, Liu HK, Yang WS, Chen BC, Chuang LM, Chang YC, Liu YW. GSK3α phosphorylates dynamin-2 to promote GLUT4 endocytosis in muscle cells. J Cell Biol 2022; 222:213725. [PMID: 36445308 PMCID: PMC9712776 DOI: 10.1083/jcb.202102119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 08/17/2022] [Accepted: 10/31/2022] [Indexed: 12/02/2022] Open
Abstract
Insulin-stimulated translocation of glucose transporter 4 (GLUT4) to plasma membrane of skeletal muscle is critical for postprandial glucose uptake; however, whether the internalization of GLUT4 is also regulated by insulin signaling remains unclear. Here, we discover that the activity of dynamin-2 (Dyn2) in catalyzing GLUT4 endocytosis is negatively regulated by insulin signaling in muscle cells. Mechanistically, the fission activity of Dyn2 is inhibited by binding with the SH3 domain of Bin1. In the absence of insulin, GSK3α phosphorylates Dyn2 to relieve the inhibition of Bin1 and promotes endocytosis. Conversely, insulin signaling inactivates GSK3α and leads to attenuated GLUT4 internalization. Furthermore, the isoform-specific pharmacological inhibition of GSK3α significantly improves insulin sensitivity and glucose tolerance in diet-induced insulin-resistant mice. Together, we identify a new role of GSK3α in insulin-stimulated glucose disposal by regulating Dyn2-mediated GLUT4 endocytosis in muscle cells. These results highlight the isoform-specific function of GSK3α on membrane trafficking and its potential as a therapeutic target for metabolic disorders.
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Affiliation(s)
- Jessica Laiman
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yen-Jung Hsu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Julie Loh
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wei-Chun Tang
- ResearchCenter for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Mei-Chun Chuang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hui-Kang Liu
- National Research Institute of Chinese Medicine, Ministry of Health and Welfare, Taipei, Taiwan,Program in the Clinical Drug Development of Herbal Medicine, Taipei Medical University, Taipei, Taiwan
| | - Wei-Shun Yang
- Division of Nephrology, Department of Internal Medicine, National Taiwan University Hospital, Hsin-Chu Branch, Hsin-Chu, Taiwan
| | - Bi-Chang Chen
- ResearchCenter for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Lee-Ming Chuang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan,Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Yi-Cheng Chang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan,Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei, Taiwan,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan,Yi-Cheng Chang:
| | - Ya-Wen Liu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan,Correspondence to Ya-Wen Liu:
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3
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Heckmann M, Klanert G, Sandner G, Lanzerstorfer P, Auer M, Weghuber J. Fluorescence Microscopy-Based Quantitation of GLUT4 Translocation. Methods Appl Fluoresc 2022; 10. [PMID: 35008072 DOI: 10.1088/2050-6120/ac4998] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 01/10/2022] [Indexed: 11/11/2022]
Abstract
Postprandial insulin-stimulated glucose uptake into target tissue is crucial for the maintenance of normal blood glucose homeostasis. This step is rate-limited by the number of facilitative glucose transporters type 4 (GLUT4) present in the plasma membrane. Since insulin resistance and impaired GLUT4 translocation are associated with the development of metabolic disorders such as type 2 diabetes, this transporter has become an important target of antidiabetic drug research. The application of screening approaches that are based on the analysis of GLUT4 translocation to the plasma membrane to identify substances with insulinomimetic properties has gained global research interest in recent years. Here, we review methods that have been implemented to quantitate the translocation of GLUT4 to the plasma membrane. These methods can be broadly divided into two sections: microscopy-based technologies (e.g., immunoelectron, confocal or total internal reflection fluorescence microscopy) and biochemical and spectrometric approaches (e.g., membrane fractionation, photoaffinity labeling or flow cytometry). In this review, we discuss the most relevant approaches applied to GLUT4 thus far, highlighting the advantages and disadvantages of these approaches, and we provide a critical discussion and outlook into new methodological opportunities.
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Affiliation(s)
- Mara Heckmann
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, Oberösterreich, 4600, AUSTRIA
| | - Gerald Klanert
- FFoQSI GmbH-Austrian Competence Centre for Feed and Food Quality, Safety and Innovation, Technopark 1C, Tulln, 3430, AUSTRIA
| | - Georg Sandner
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, Oberösterreich, 4600, AUSTRIA
| | - Peter Lanzerstorfer
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, Oberösterreich, 4600, AUSTRIA
| | - Manfred Auer
- Division of Pathway Medicine, University of Edinburgh, University of Edinburgh Medical School, The Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, Edinburgh, EH8 9AB, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Julian Weghuber
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, Oberösterreich, 4600, AUSTRIA
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4
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Camus MD, Camus SM. Characterizing Membrane Traffic in the Early Secretory Pathway Using the RUSH Retention System. Methods Mol Biol 2022; 2473:3-14. [PMID: 35819754 DOI: 10.1007/978-1-0716-2209-4_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The early secretory pathway encompasses the endoplasmic reticulum (ER) and the ER-Golgi intermediate compartment (ERGIC) organelles. The ERGIC is now understood to be a complex cargo sorting hub involved in a variety of cellular and tissue processes, however the traffic pathways to and from the ERGIC are still unclear.Classical methods employed for the analysis of a cargo 's journey along the secretory pathway rely on reversible traffic blocks leading to cargo accumulation in the ER . Although these methods were key to characterize Golgi and post-Golgi traffic routes, their poor specificity to the cargo of interest and limited spatiotemporal resolution make them inadequate for the fine characterization of cargo traffic in the early secretory pathway.In this chapter, we describe a protocol to study the traffic of cargo proteins in the early secretory pathway using the Retention Using Selective Hook (RUSH ) system, a highly specific and sensitive tracking system with a high spatiotemporal resolution. Taking GLUT4 and GLUT1 as examples of unconventionally and conventionally secreted cargo respectively, we describe the steps to clone the cargoes in the RUSH vector and follow and quantify their traffic along the early secretory pathway. This RUSH method can also be used to study the traffic of other cargo proteins in the early secretory pathway.
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Affiliation(s)
- Marine D Camus
- Université Paris Saclay, INSERM UMR1184 Centre for Immunology of Viral Infections and Autoimmune Diseases, Paris, France
| | - Stephane M Camus
- Université de Paris, INSERM UMR970, Paris Cardiovascular Research Center, Paris, France.
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5
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Kishikawa T, Higuchi H, Wang L, Panch N, Maymi V, Best S, Lee S, Notoya G, Toker A, Matesic LE, Wulf GM, Wei W, Otsuka M, Koike K, Clohessy JG, Lee YR, Pandolfi PP. WWP1 inactivation enhances efficacy of PI3K inhibitors while suppressing their toxicities in breast cancer models. J Clin Invest 2021; 131:140436. [PMID: 34907909 DOI: 10.1172/jci140436] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 10/27/2021] [Indexed: 12/25/2022] Open
Abstract
Activation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway is a pervasive event in tumorigenesis due to PI3K mutation and dysfunction of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Pharmacological inhibition of PI3K has resulted in variable clinical outcomes, however, raising questions regarding the possible mechanisms of unresponsiveness and resistance to treatment. WWP1 is an oncogenic HECT-type ubiquitin E3 ligase frequently amplified and mutated in multiple cancers, as well as in the germ lines of patients predisposed to cancer, and was recently found to activate PI3K signaling through PTEN inactivation. Here, we demonstrate that PTEN dissociated from the plasma membrane upon treatment with PI3K inhibitors through WWP1 activation, whereas WWP1 genetic or pharmacological inhibition restored PTEN membrane localization, synergizing with PI3K inhibitors to suppress tumor growth both in vitro and in vivo. Furthermore, we demonstrate that WWP1 inhibition attenuated hyperglycemia and the consequent insulin feedback, which is a major tumor-promoting side effect of PI3K inhibitors. Mechanistically, we found that AMPKα2 was ubiquitinated and, in turn, inhibited in its activatory phosphorylation by WWP1, whereas WWP1 inhibition facilitated AMPKα2 activity in the muscle to compensate for the reduction in glucose uptake observed upon PI3K inhibition. Thus, our identification of the cell-autonomous and systemic roles of WWP1 inhibition expands the therapeutic potential of PI3K inhibitors and reveals new avenues of combination cancer therapy.
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Affiliation(s)
- Takahiro Kishikawa
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.,Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Higuchi
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Limei Wang
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Nivedita Panch
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Valerie Maymi
- Preclinical Murine Pharmacogenetics Facility and Mouse Hospital, and
| | - Sachem Best
- Preclinical Murine Pharmacogenetics Facility and Mouse Hospital, and
| | - Samuel Lee
- Preclinical Murine Pharmacogenetics Facility and Mouse Hospital, and
| | - Genso Notoya
- Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Alex Toker
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Lydia E Matesic
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, USA
| | - Gerburg M Wulf
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine, Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Motoyuki Otsuka
- Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kazuhiko Koike
- Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - John G Clohessy
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.,Preclinical Murine Pharmacogenetics Facility and Mouse Hospital, and
| | - Yu-Ru Lee
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Pier Paolo Pandolfi
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.,Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy.,Renown Institute for Cancer, Nevada System of Higher Education, Reno, Nevada, USA
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6
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Picatoste B, Yammine L, Leahey RA, Soares D, Johnson EF, Cohen P, McGraw TE. Defective insulin-stimulated GLUT4 translocation in brown adipocytes induces systemic glucose homeostasis dysregulation independent of thermogenesis in female mice. Mol Metab 2021; 53:101305. [PMID: 34303022 PMCID: PMC8363886 DOI: 10.1016/j.molmet.2021.101305] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 06/24/2021] [Accepted: 07/14/2021] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVE Recent studies indicate that brown adipose tissue, in addition to its role in thermogenesis, has a role in the regulation of whole-body metabolism. Here we characterize the metabolic effects of deleting Rab10, a protein key for insulin stimulation of glucose uptake into white adipocytes, solely from brown adipocytes. METHODS We used a murine brown adipocyte cell line and stromal vascular fraction-derived in vitro differentiated brown adipocytes to study the role of Rab10 in insulin-stimulated GLUT4 translocation to the plasma membrane and insulin-stimulated glucose uptake. We generated a brown adipocyte-specific Rab10 knockout for in vivo studies of metabolism and thermoregulation. RESULTS We demonstrate that deletion of Rab10 from brown adipocytes results in a two-fold reduction of insulin-stimulated glucose transport by reducing translocation of the GLUT4 glucose transporter to the plasma membrane, an effect linked to whole-body glucose intolerance and insulin resistance in female mice. This effect on metabolism is independent of the thermogenic function of brown adipocytes, thereby revealing a metabolism-specific role for brown adipocytes in female mice. The reduced glucose uptake induced by Rab10 deletion disrupts ChREBP regulation of de novo lipogenesis (DNL) genes, providing a potential link between DNL in brown adipocytes and whole-body metabolic regulation in female mice. However, deletion of Rab10 from male mice does not induce systemic insulin resistance, although ChREBP regulation is disrupted. CONCLUSIONS Our studies of Rab10 reveal the role of insulin-regulated glucose transport into brown adipocytes in whole-body metabolic homeostasis of female mice. Importantly, the contribution of brown adipocytes to whole-body metabolic regulation is independent of its role in thermogenesis. It is unclear whether the whole-body metabolic sexual dimorphism is because female mice are permissive to the effects of Rab10 deletion from brown adipocytes or because male mice are resistant to the effect.
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Affiliation(s)
- Belén Picatoste
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Lucie Yammine
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Rosemary A. Leahey
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - David Soares
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Emma F. Johnson
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Paul Cohen
- Laboratory of Molecular Metabolism, The Rockefeller University, New York, NY, 10065, USA
| | - Timothy E. McGraw
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA,Department of Cardiothoracic Surgery, Weill Cornell Medical College, New York, NY, 10065, USA,Corresponding author. Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA.
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7
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Endo M, Miyasaki M, Li Q, Kawamura G, Ozawa T. A Detection Method for GLUT4 Exocytosis Based on Spontaneous Split Luciferase Complementation. ANAL SCI 2019; 35:835-838. [PMID: 31281129 DOI: 10.2116/analsci.19c003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Glucose transporter 4 (GLUT4) is an insulin-regulated glucose transporter, which is vital for blood glucose homeostasis. To clarify the physiological roles of GLUT4, quantitative measurement of GLUT4 exocytosis is indispensable. Herein, we show a rapid detection system for GLUT4 on the cell surface using spontaneous split-luciferase reconstitution. Upon insulin-induced GLUT4 exocytosis, GLUT4 was exposed outside, where luciferase is reconstituted and emitted luminescence. Pretreatment with inhibitors reduced the insulin-induced signal elevation. The results indicate that the developed method is applicable to high-throughput analysis on GLUT4 trafficking, which will greatly accelerate comprehensive research on the physiological roles of GLUT4.
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Affiliation(s)
- Mizuki Endo
- Department of Chemistry, School of Science, The University of Tokyo
| | - Masashi Miyasaki
- Department of Chemistry, School of Science, The University of Tokyo
| | - Qiaojing Li
- Department of Chemistry, School of Science, The University of Tokyo
| | - Genki Kawamura
- Department of Chemistry, School of Science, The University of Tokyo
| | - Takeaki Ozawa
- Department of Chemistry, School of Science, The University of Tokyo
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8
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Abstract
A pivotal metabolic function of insulin is the stimulation of glucose uptake into muscle and adipose tissues. The discovery of the insulin-responsive glucose transporter type 4 (GLUT4) protein in 1988 inspired its molecular cloning in the following year. It also spurred numerous cellular mechanistic studies laying the foundations for how insulin regulates glucose uptake by muscle and fat cells. Here, we reflect on the importance of the GLUT4 discovery and chronicle additional key findings made in the past 30 years. That exocytosis of a multispanning membrane protein regulates cellular glucose transport illuminated a novel adaptation of the secretory pathway, which is to transiently modulate the protein composition of the cellular plasma membrane. GLUT4 controls glucose transport into fat and muscle tissues in response to insulin and also into muscle during exercise. Thus, investigation of regulated GLUT4 trafficking provides a major means by which to map the essential signaling components that transmit the effects of insulin and exercise. Manipulation of the expression of GLUT4 or GLUT4-regulating molecules in mice has revealed the impact of glucose uptake on whole-body metabolism. Remaining gaps in our understanding of GLUT4 function and regulation are highlighted here, along with opportunities for future discoveries and for the development of therapeutic approaches to manage metabolic disease.
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Affiliation(s)
- Amira Klip
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - Timothy E McGraw
- Department of Biochemistry, Weill Medical College of Cornell University, New York, New York 10065
| | - David E James
- Charles Perkins Centre, School of Life and Environmental Sciences, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia
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9
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Fumagalli M, Camus SM, Diekmann Y, Burke A, Camus MD, Norman PJ, Joseph A, Abi-Rached L, Benazzo A, Rasteiro R, Mathieson I, Topf M, Parham P, Thomas MG, Brodsky FM. Genetic diversity of CHC22 clathrin impacts its function in glucose metabolism. eLife 2019; 8:41517. [PMID: 31159924 PMCID: PMC6548504 DOI: 10.7554/elife.41517] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 05/01/2019] [Indexed: 01/29/2023] Open
Abstract
CHC22 clathrin plays a key role in intracellular membrane traffic of the insulin-responsive glucose transporter GLUT4 in humans. We performed population genetic and phylogenetic analyses of the CHC22-encoding CLTCL1 gene, revealing independent gene loss in at least two vertebrate lineages, after arising from gene duplication. All vertebrates retained the paralogous CLTC gene encoding CHC17 clathrin, which mediates endocytosis. For vertebrates retaining CLTCL1, strong evidence for purifying selection supports CHC22 functionality. All human populations maintained two high frequency CLTCL1 allelic variants, encoding either methionine or valine at position 1316. Functional studies indicated that CHC22-V1316, which is more frequent in farming populations than in hunter-gatherers, has different cellular dynamics than M1316-CHC22 and is less effective at controlling GLUT4 membrane traffic, altering its insulin-regulated response. These analyses suggest that ancestral human dietary change influenced selection of allotypes that affect CHC22's role in metabolism and have potential to differentially influence the human insulin response.
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Affiliation(s)
- Matteo Fumagalli
- Department of Life Sciences, Imperial College London, Ascot, United Kingdom.,Research Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom.,Research Department of Genetics, Evolution and Environment, Division of Biosciences, University College London, London, United Kingdom.,UCL Genetics Institute, University College London, London, United Kingdom
| | - Stephane M Camus
- Research Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Yoan Diekmann
- Research Department of Genetics, Evolution and Environment, Division of Biosciences, University College London, London, United Kingdom.,UCL Genetics Institute, University College London, London, United Kingdom
| | - Alice Burke
- Research Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Marine D Camus
- Research Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Paul J Norman
- Division of Bioinformatics and Personalized Medicine, University of Colorado, Aurora, United States.,Department of Microbiology and Immunology, University of Colorado, Aurora, United States
| | - Agnel Joseph
- Institute of Structural and Molecular Biology, Birkbeck College and University College London, London, United Kingdom
| | - Laurent Abi-Rached
- Aix-Marseille Univ, IRD, MEPHI, IHU Méditerranée Infection, CNRS, Marseille, France
| | - Andrea Benazzo
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Rita Rasteiro
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Iain Mathieson
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Maya Topf
- Institute of Structural and Molecular Biology, Birkbeck College and University College London, London, United Kingdom
| | - Peter Parham
- Department of Structural Biology, Stanford University, Stanford, CA, United States.,Department of Microbiology and Immunology, Stanford University, Stanford, CA, United States
| | - Mark G Thomas
- Research Department of Genetics, Evolution and Environment, Division of Biosciences, University College London, London, United Kingdom.,UCL Genetics Institute, University College London, London, United Kingdom
| | - Frances M Brodsky
- Research Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom.,Institute of Structural and Molecular Biology, Birkbeck College and University College London, London, United Kingdom
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10
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Lu Y, Ma X, Kong Q, Xu Y, Hu J, Wang F, Qin W, Wang L, Xiong W. Novel dual-color drug screening model for GLUT4 translocation in adipocytes. Mol Cell Probes 2019; 43:6-12. [PMID: 30639558 DOI: 10.1016/j.mcp.2019.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/09/2019] [Accepted: 01/09/2019] [Indexed: 12/22/2022]
Abstract
Insulin-responsive glucose transporter type 4 (GLUT4) translocation plays a major role in controlling glucose uptake in adipose tissue and muscle, maintaining homeostasis and preventing hyperglycemia. Screening for chemicals enhancing GLUT4 translocation is an approach for identifying hits of drug development for type 2 diabetes. Here we developed a novel functional dual-color probe, pHluorin-GLUT4-mOrange2, and constructed 3T3-L1 adipocytes based screening system to simply and efficiently screen new compounds stimulating GLUT4 translocation. Based on this system, we successfully identified a few hits facilitating GLUT4 translocation. In conclusion, we developed an easy-to-apply dual color GLUT4 probe to monitor GLUT4 translocation in insulin-responsive cells, which could be alternatively employed to high-throughput screen compounds regulating GLUT4 translocation and glucose uptake, even to dissect GLTU4 approaching, docking and fusion with the plasma membrane (PM), and to reveal relevant molecular mechanisms involved in these steps as expected.
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Affiliation(s)
- Yanting Lu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiuli Ma
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Qinghua Kong
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Yuhui Xu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Jing Hu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Fang Wang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Wanying Qin
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Libin Wang
- The General Hospital of Ningxia Medical University, Department of Beijing National Biochip Research Center Sub-Center in Ningxia, Yinchuan, 750004, China.
| | - Wenyong Xiong
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; The General Hospital of Ningxia Medical University, Department of Beijing National Biochip Research Center Sub-Center in Ningxia, Yinchuan, 750004, China.
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11
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Dandelion Chloroform Extract Promotes Glucose Uptake via the AMPK/GLUT4 Pathway in L6 Cells. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 2018:1709587. [PMID: 30524480 PMCID: PMC6247471 DOI: 10.1155/2018/1709587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 08/02/2018] [Accepted: 09/04/2018] [Indexed: 01/01/2023]
Abstract
The number of patients with type 2 diabetes mellitus (T2DM) is increasing rapidly worldwide. Glucose transporter 4 (GLUT4) is one of the main proteins that transport blood glucose into the cells and is a target in the treatment of T2DM. In this study, we investigated the mechanism of action of dandelion chloroform extract (DCE) on glucose uptake in L6 cells. The glucose consumption of L6 cell culture supernatant was measured by a glucose uptake assay kit, and the dynamic changes of intracellular GLUT4 and calcium (Ca2+) levels were monitored by laser scanning confocal microscopy in L6 cell lines stably expressing IRAP-mOrange. The GLUT4 fusion with the plasma membrane (PM) was traced via myc-GLUT4-mOrange. GLUT4 expression and AMP-activated protein kinase (AMPK), protein kinase B (PKB/Akt), protein kinase C (PKC), and phosphorylation levels were determined by performing western blotting. GLUT4 mRNA expression was detected by real-time PCR. DCE up-regulated GLUT4 expression, promoted GLUT4 translocation and fusion to the membrane eventually leading to glucose uptake, and induced AMPK phosphorylation in L6 cells. The AMPK inhibitory compound C significantly inhibited DCE-induced GLUT4 expression and translocation while no inhibitory effect was observed by the phosphatidylinositol 3-kinase (PI3K) inhibitor Wortmannin and PKC inhibitor Gö6983. These data suggested that DCE promoted GLUT4 expression and transport to the membrane through the AMPK signaling pathway, thereby stimulating GLUT4 fusion with PM to enhance glucose uptake in L6 cells. DCE-induced GLUT4 translocation was also found to be Ca2+-independent. Together, these findings indicate that DCE could be a new hypoglycemic agent for the treatment of T2DM.
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Feng D, Amgalan D, Singh R, Wei J, Wen J, Wei TP, McGraw TE, Kitsis RN, Pessin JE. SNAP23 regulates BAX-dependent adipocyte programmed cell death independently of canonical macroautophagy. J Clin Invest 2018; 128:3941-3956. [PMID: 30102258 PMCID: PMC6118598 DOI: 10.1172/jci99217] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 06/26/2018] [Indexed: 01/19/2023] Open
Abstract
The t-SNARE protein SNAP23 conventionally functions as a component of the cellular machinery required for intracellular transport vesicle fusion with target membranes and has been implicated in the regulation of fasting glucose levels, BMI, and type 2 diabetes. Surprisingly, we observed that adipocyte-specific KO of SNAP23 in mice resulted in a temporal development of severe generalized lipodystrophy associated with adipose tissue inflammation, insulin resistance, hyperglycemia, liver steatosis, and early death. This resulted from adipocyte cell death associated with an inhibition of macroautophagy and lysosomal degradation of the proapoptotic regulator BAX, with increased BAX activation. BAX colocalized with LC3-positive autophagic vacuoles and was increased upon treatment with lysosome inhibitors. Moreover, BAX deficiency suppressed the lipodystrophic phenotype in the adipocyte-specific SNAP23-KO mice and prevented cell death. In addition, ATG9 deficiency phenocopied SNAP23 deficiency, whereas ATG7 deficiency had no effect on BAX protein levels, BAX activation, or apoptotic cell death. These data demonstrate a role for SNAP23 in the control of macroautophagy and programmed cell death through an ATG9-dependent, but ATG7-independent, pathway regulating BAX protein levels and BAX activation.
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Affiliation(s)
- Daorong Feng
- Department of Medicine
- Department of Molecular Pharmacology
| | | | - Rajat Singh
- Department of Medicine
- Department of Molecular Pharmacology
- Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Jianwen Wei
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, and
| | - Jennifer Wen
- Department of Biochemistry, Weill Medical College of Cornell University, New York, New York, USA
| | | | - Timothy E. McGraw
- Department of Biochemistry, Weill Medical College of Cornell University, New York, New York, USA
| | - Richard N. Kitsis
- Department of Medicine
- Department of Cell Biology, and
- Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, New York, USA
- Wilf Family Cardiovascular Research Center, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Jeffrey E. Pessin
- Department of Medicine
- Department of Molecular Pharmacology
- Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, New York, USA
- Wilf Family Cardiovascular Research Center, Albert Einstein College of Medicine, Bronx, New York, USA
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13
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Huang Y, Hao J, Tian D, Wen Y, Zhao P, Chen H, Lv Y, Yang X. Antidiabetic Activity of a Flavonoid-Rich Extract From Sophora davidii (Franch.) Skeels in KK-Ay Mice via Activation of AMP-Activated Protein Kinase. Front Pharmacol 2018; 9:760. [PMID: 30061831 PMCID: PMC6055046 DOI: 10.3389/fphar.2018.00760] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/22/2018] [Indexed: 12/19/2022] Open
Abstract
The present study was undertaken to investigate the hypoglycemic activity and potential mechanisms of action of a flavonoid-rich extract from Sophora davidii (Franch.) Skeels (SD-FRE) through in vitro and in vivo studies. Four main flavonoids of SD-FRE namely apigenin, maackiain, leachianone A and leachianone B were purified and identified. In vitro, SD-FRE significantly promoted the translocation and expression of glucose transporter 4 (GLUT4) in L6 cells, which was significantly inhibited by Compound C (AMPK inhibitor), but not by Wortmannin (PI3K inhibitor) or Gö6983 (PKC inhibitor). These results indicated that SD-FRE enhanced GLUT4 expression and translocation to the plasma membrane via the AMPK pathway and finally resulted in an increase of glucose uptake. In vivo, using a spontaneously type 2 diabetic model, KK-Ay mice received intragastric administration of SD-FRE for 4 weeks. As a consequence, SD-FRE significantly alleviated the hyperglycemia, glucose intolerance, insulin resistance and hyperlipidemia in these mice. Hepatic steatosis, islet hypertrophy and larger adipocyte size were observed in KK-Ay mice. However, these pathological changes were effectively relieved by SD-FRE treatment. SD-FRE promoted GLUT4 expression and activated AMPK phosphorylation in insulin target tissues (muscle, adipose tissue and liver) of KK-Ay mice, thus facilitating glucose utilization to ameliorate insulin resistance. Regulation of ACC phosphorylation and PPARγ were also involved in the antidiabetic effects of SD-FRE. Taken together, these findings indicated that SD-FRE has the potential to alleviate type 2 diabetes.
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Affiliation(s)
- Yun Huang
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Ji Hao
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Di Tian
- School of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Yanzhang Wen
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Ping Zhao
- School of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Hao Chen
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China.,College of Pharmacy, Guangxi University of Chinese Medicine, Nanning, China
| | - Yibin Lv
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Xinzhou Yang
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
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14
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Isolation of state-dependent monoclonal antibodies against the 12-transmembrane domain glucose transporter 4 using virus-like particles. Proc Natl Acad Sci U S A 2018; 115:E4990-E4999. [PMID: 29769329 DOI: 10.1073/pnas.1716788115] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The insulin-responsive 12-transmembrane transporter GLUT4 changes conformation between an inward-open state and an outward-open state to actively facilitate cellular glucose uptake. Because of the difficulties of generating conformational mAbs against complex and highly conserved membrane proteins, no reliable tools exist to measure GLUT4 at the cell surface, follow its trafficking, or detect the conformational state of the protein. Here we report the isolation and characterization of conformational mAbs that recognize the extracellular and intracellular domains of GLUT4, including mAbs that are specific for the inward-open and outward-open states of GLUT4. mAbs against GLUT4 were generated using virus-like particles to present this complex membrane protein in its native conformation and using a divergent host species (chicken) for immunization to overcome immune tolerance. As a result, the isolated mAbs recognize conformational epitopes on native GLUT4 in cells, with apparent affinities as high as 1 pM and with specificity for GLUT4 across the human membrane proteome. Epitope mapping using shotgun mutagenesis alanine scanning across the 509 amino acids of GLUT4 identified the binding epitopes for mAbs specific for the states of GLUT4 and allowed the comprehensive identification of the residues that functionally control the GLUT4 inward-open and outward-open states. The mAbs identified here will be valuable molecular tools for monitoring GLUT4 structure, function, and trafficking, for differentiating GLUT4 conformational states, and for the development of novel therapeutics for the treatment of diabetes.
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15
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Haeusler RA, McGraw TE, Accili D. Biochemical and cellular properties of insulin receptor signalling. Nat Rev Mol Cell Biol 2018; 19:31-44. [PMID: 28974775 PMCID: PMC5894887 DOI: 10.1038/nrm.2017.89] [Citation(s) in RCA: 427] [Impact Index Per Article: 71.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The mechanism of insulin action is a central theme in biology and medicine. In addition to the rather rare condition of insulin deficiency caused by autoimmune destruction of pancreatic β-cells, genetic and acquired abnormalities of insulin action underlie the far more common conditions of type 2 diabetes, obesity and insulin resistance. The latter predisposes to diseases ranging from hypertension to Alzheimer disease and cancer. Hence, understanding the biochemical and cellular properties of insulin receptor signalling is arguably a priority in biomedical research. In the past decade, major progress has led to the delineation of mechanisms of glucose transport, lipid synthesis, storage and mobilization. In addition to direct effects of insulin on signalling kinases and metabolic enzymes, the discovery of mechanisms of insulin-regulated gene transcription has led to a reassessment of the general principles of insulin action. These advances will accelerate the discovery of new treatment modalities for diabetes.
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Affiliation(s)
- Rebecca A Haeusler
- Columbia University College of Physicians and Surgeons, Department of Pathology and Cell Biology, New York, New York 10032, USA
| | - Timothy E McGraw
- Weill Cornell Medicine, Departments of Biochemistry and Cardiothoracic Surgery, New York, New York 10065, USA
| | - Domenico Accili
- Columbia University College of Physicians & Surgeons, Department of Medicine, New York, New York 10032, USA
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16
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Translocation and Redistribution of GLUT4 Using a Dual-Labeled Reporter Assay. Methods Mol Biol 2017. [PMID: 29218525 DOI: 10.1007/978-1-4939-7507-5_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
It is crucial to determine the regulation of GLUT4 translocation and redistribution to the plasma membrane. The HA-GLUT4-GFP dual-reporter construct has become an important tool in the assessment of GLUT4 recycling in cultured adipocytes and myocytes. Through the use of light microscopy, this reporter construct allows for visualization of GLUT4 specifically at the cell surface or GLUT4 that has recycled from the cell surface while simultaneously marking the total GLUT4 pool. Here, we discuss and outline the general application of this reporter construct and its use in evaluating GLUT4 translocation within cultured adipocytes.
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17
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Chaudhary N, Gonzalez E, Chang SH, Geng F, Rafii S, Altorki NK, McGraw TE. Adenovirus Protein E4-ORF1 Activation of PI3 Kinase Reveals Differential Regulation of Downstream Effector Pathways in Adipocytes. Cell Rep 2017; 17:3305-3318. [PMID: 28009298 DOI: 10.1016/j.celrep.2016.11.082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 10/05/2016] [Accepted: 11/28/2016] [Indexed: 12/13/2022] Open
Abstract
Insulin activation of phosphatidylinositol 3-kinase (PI3K) regulates metabolism, including the translocation of the Glut4 glucose transporter to the plasma membrane and inactivation of the FoxO1 transcription factor. Adenoviral protein E4-ORF1 stimulates cellular glucose metabolism by mimicking growth-factor activation of PI3K. We have used E4-ORF1 as a tool to dissect PI3K-mediated signaling in adipocytes. E4-ORF1 activation of PI3K in adipocytes recapitulates insulin regulation of FoxO1 but not regulation of Glut4. This uncoupling of PI3K effects occurs despite E4-ORF1 activating PI3K and downstream signaling to levels achieved by insulin. Although E4-ORF1 does not fully recapitulate insulin's effects on Glut4, it enhances insulin-stimulated insertion of Glut4-containing vesicles to the plasma membrane independent of Rab10, a key regulator of Glut4 trafficking. E4-ORF1 also stimulates plasma membrane translocation of ubiquitously expressed Glut1 glucose transporter, an effect that is likely essential for E4-ORF1 to promote an anabolic metabolism in a broad range of cell types.
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Affiliation(s)
- Natasha Chaudhary
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Eva Gonzalez
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Sung-Hee Chang
- Department of Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Fuqiang Geng
- Department of Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Shahin Rafii
- Department of Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Nasser K Altorki
- Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, NY 10065, USA; Lung Cancer Program, Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10065, USA
| | - Timothy E McGraw
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA; Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, NY 10065, USA; Lung Cancer Program, Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10065, USA.
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18
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Du K, Murakami S, Sun Y, Kilpatrick CL, Luscher B. DHHC7 Palmitoylates Glucose Transporter 4 (Glut4) and Regulates Glut4 Membrane Translocation. J Biol Chem 2017; 292:2979-2991. [PMID: 28057756 DOI: 10.1074/jbc.m116.747139] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 12/30/2016] [Indexed: 11/06/2022] Open
Abstract
Insulin-dependent translocation of glucose transporter 4 (Glut4) to the plasma membrane plays a key role in the dynamic regulation of glucose homeostasis. We recently showed that this process is critically dependent on palmitoylation of Glut4 at Cys-223. To gain further insights into the regulation of Glut4 palmitoylation, we set out to identify the palmitoyl acyltransferase (PAT) involved. Here we report that among 23 mammalian DHHC proteins, DHHC7 is the major Glut4 PAT, based on evidence that ectopic expression of DHHC7 increased Glut4 palmitoylation, whereas DHHC7 knockdown in 3T3-L1 adipocytes and DHHC7 KO in adipose tissue and muscle decreased Glut4 palmitoylation. Moreover, inactivation of DHHC7 suppressed insulin-dependent Glut4 membrane translocation in both 3T3-L1 adipocytes and primary adipocytes. Finally, DHHC7 KO mice developed hyperglycemia and glucose intolerance, thereby confirming that DHHC7 represents the principal PAT for Glut4 and that this mechanism is essential for insulin-regulated glucose homeostasis.
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Affiliation(s)
- Keyong Du
- From the Molecular Oncology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111 and
| | | | - Yingmin Sun
- From the Molecular Oncology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111 and
| | - Casey L Kilpatrick
- Department of Biochemistry and Molecular Biology.,Department of Biology, and.,Center for Molecular Investigation of Neurological Disorders, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Bernhard Luscher
- Department of Biochemistry and Molecular Biology.,Department of Biology, and.,Center for Molecular Investigation of Neurological Disorders, Pennsylvania State University, University Park, Pennsylvania 16802
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19
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Gao L, Chen J, Gao J, Wang H, Xiong W. Super-resolution microscopy reveals the insulin-resistance-regulated reorganization of GLUT4 on plasma membranes. J Cell Sci 2016; 130:396-405. [PMID: 27888215 DOI: 10.1242/jcs.192450] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 11/11/2016] [Indexed: 02/01/2023] Open
Abstract
GLUT4 (also known as SLC2A4) is essential for glucose uptake in skeletal muscles and adipocytes, which play central roles in whole-body glucose metabolism. Here, using direct stochastic optical reconstruction microscopy (dSTORM) to investigate the characteristics of plasma-membrane-fused GLUT4 at the single-molecule level, we have demonstrated that insulin and insulin resistance regulate the spatial organization of GLUT4 in adipocytes. Stimulation with insulin shifted the balance of GLUT4 on the plasma membrane toward a more dispersed configuration. In contrast, insulin resistance induced a more clustered distribution of GLUT4 and increased the mean number of molecules per cluster. Furthermore, our data demonstrate that the F5QQI motif and lipid rafts mediate the maintenance of GLUT4 clusters on the plasma membrane. Mutation of F5QQI (F5QQA-GLUT4) induced a more clustered distribution of GLUT4; moreover, destruction of lipid rafts in adipocytes expressing F5QQA-GLUT4 dramatically decreased the percentage of large clusters and the mean number of molecules per cluster. In conclusion, our data clarify the effects of insulin stimulation or insulin resistance on GLUT4 reorganization on the plasma membrane and reveal new pathogenic mechanisms of insulin resistance.
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Affiliation(s)
- Lan Gao
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, P.R. China.,Graduate University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Junling Chen
- Graduate University of Chinese Academy of Sciences, Beijing 100049, P.R. China.,State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilil 130022, P.R. China
| | - Jing Gao
- Graduate University of Chinese Academy of Sciences, Beijing 100049, P.R. China.,State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilil 130022, P.R. China
| | - Hongda Wang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilil 130022, P.R. China
| | - Wenyong Xiong
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, P.R. China
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20
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Bruno J, Brumfield A, Chaudhary N, Iaea D, McGraw TE. SEC16A is a RAB10 effector required for insulin-stimulated GLUT4 trafficking in adipocytes. J Cell Biol 2016; 214:61-76. [PMID: 27354378 PMCID: PMC4932369 DOI: 10.1083/jcb.201509052] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 06/08/2016] [Indexed: 12/19/2022] Open
Abstract
Sec16A is known to be required for COPII vesicle formation from the ER. Here, Bruno et al. show that, independent of its role at the ER, Sec16A is a RAB10 effector involved in the insulin-stimulated formation of specialized transport vesicles that ferry the GLUT4 glucose transporter to the plasma membrane of adipocytes. RAB10 is a regulator of insulin-stimulated translocation of the GLUT4 glucose transporter to the plasma membrane (PM) of adipocytes, which is essential for whole-body glucose homeostasis. We establish SEC16A as a novel RAB10 effector in this process. Colocalization of SEC16A with RAB10 is augmented by insulin stimulation, and SEC16A knockdown attenuates insulin-induced GLUT4 translocation, phenocopying RAB10 knockdown. We show that SEC16A and RAB10 promote insulin-stimulated mobilization of GLUT4 from a perinuclear recycling endosome/TGN compartment. We propose RAB10–SEC16A functions to accelerate formation of the vesicles that ferry GLUT4 to the PM during insulin stimulation. Because GLUT4 continually cycles between the PM and intracellular compartments, the maintenance of elevated cell-surface GLUT4 in the presence of insulin requires accelerated biogenesis of the specialized GLUT4 transport vesicles. The function of SEC16A in GLUT4 trafficking is independent of its previously characterized activity in ER exit site formation and therefore independent of canonical COPII-coated vesicle function. However, our data support a role for SEC23A, but not the other COPII components SEC13, SEC23B, and SEC31, in the insulin stimulation of GLUT4 trafficking, suggesting that vesicles derived from subcomplexes of COPII coat proteins have a role in the specialized trafficking of GLUT4.
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Affiliation(s)
- Joanne Bruno
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065 Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10065
| | | | - Natasha Chaudhary
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - David Iaea
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Timothy E McGraw
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065 Department of Cardiothoracic Surgery, Weill Cornell Medical College, New York, NY 10065
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Talantikite M, Berenguer M, Gonzalez T, Alessi MC, Poggi M, Peiretti F, Govers R. The first intracellular loop of GLUT4 contains a retention motif. J Cell Sci 2016; 129:2273-84. [DOI: 10.1242/jcs.183525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 04/20/2016] [Indexed: 01/02/2023] Open
Abstract
Glucose transporter GLUT4 plays a major role in glucose homeostasis and is efficiently retained intracellularly in adipocytes and myocytes. To simplify the analysis of its retention, various intracellular GLUT4 domains were fused individually to reporter molecules. Of the four short cytoplasmic loops of GLUT4, only the first nine-residue-long loop conferred intracellular retention of truncated forms of the transferrin receptor and CD4 in adipocytes. In contrast, the same loop of GLUT1 was without effect. The reporter molecules to which the first loop of GLUT4 was fused localized, unlike GLUT4, to the TGN, possibly explaining why these molecules did not respond to insulin. The retention induced by the GLUT4 loop was specific to adipocytes as it did not induce retention in preadipocytes. Of the SQWLGRKRA sequence that constitutes this loop, mutation of either the tryptophan or lysine residue abrogated reporter retention. Mutation of these residues individually into alanines in the full-length GLUT4 molecule resulted in a decreased retention for GLUT4-W105A. We conclude that the first intracellular loop of GLUT4 contains retention motif WLGRK, in which Trp105 plays a prominent role.
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Affiliation(s)
- Maya Talantikite
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
| | - Marion Berenguer
- Inserm U895, Mediterranean Research Center for Molecular Medicine (C3M), Nice, F-06204, France
| | - Teresa Gonzalez
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
| | - Marie Christine Alessi
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
| | - Marjorie Poggi
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
| | - Franck Peiretti
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
| | - Roland Govers
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
- Inserm U895, Mediterranean Research Center for Molecular Medicine (C3M), Nice, F-06204, France
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TUSC5 regulates insulin-mediated adipose tissue glucose uptake by modulation of GLUT4 recycling. Mol Metab 2015; 4:795-810. [PMID: 26629404 PMCID: PMC4632119 DOI: 10.1016/j.molmet.2015.08.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 08/11/2015] [Accepted: 08/18/2015] [Indexed: 12/26/2022] Open
Abstract
Objective Failure to properly dispose of glucose in response to insulin is a serious health problem, occurring during obesity and is associated with type 2 diabetes development. Insulin-stimulated glucose uptake is facilitated by the translocation and plasma membrane fusion of vesicles containing glucose transporter 4 (GLUT4), the rate-limiting step of post-prandial glucose disposal. Methods We analyzed the role of Tusc5 in the regulation of insulin-stimulated Glut4-mediated glucose uptake in vitro and in vivo. Furthermore, we measured Tusc5 expression in two patient cohorts. Results Herein, we report that TUSC5 controls insulin-stimulated glucose uptake in adipocytes, in vitro and in vivo. TUSC5 facilitates the proper recycling of GLUT4 and other key trafficking proteins during prolonged insulin stimulation, thereby enabling proper protein localization and complete vesicle formation, processes that ultimately enable insulin-stimulated glucose uptake. Tusc5 knockout mice exhibit impaired glucose disposal and TUSC5 expression is predictive of glucose tolerance in obese individuals, independent of body weight. Furthermore, we show that TUSC5 is a PPARγ target and in its absence the anti-diabetic effects of TZDs are significantly blunted. Conclusions Collectively, these findings establish TUSC5 as an adipose tissue-specific protein that enables proper protein recycling, linking the ubiquitous vesicle traffic machinery with tissue-specific insulin-mediated glucose uptake into adipose tissue and the maintenance of a healthy metabolic phenotype in mice and humans. Tusc5 regulates glucose uptake in adipose tissue by modulating the GSV recycling machinery. Tusc5 knockout mice develop insulin resistance due to impaired adipose tissue glucose uptake. Rosiglitazone improves glucose homeostasis in part through the induction of Tusc5. Tusc5 is a novel adipose specific adaptor protein linking Glut4 trafficking to the ubiquitous machinery.
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23
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Lanzerstorfer P, Stadlbauer V, Chtcheglova LA, Haselgrübler R, Borgmann D, Wruss J, Hinterdorfer P, Schröder K, Winkler SM, Höglinger O, Weghuber J. Identification of novel insulin mimetic drugs by quantitative total internal reflection fluorescence (TIRF) microscopy. Br J Pharmacol 2015; 171:5237-51. [PMID: 25039620 PMCID: PMC4262000 DOI: 10.1111/bph.12845] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 06/18/2014] [Accepted: 06/27/2014] [Indexed: 12/25/2022] Open
Abstract
Background and Purpose Insulin stimulates the transport of glucose in target tissues by triggering the translocation of glucose transporter 4 (GLUT4) to the plasma membrane. Resistance to insulin, the major abnormality in type 2 diabetes, results in a decreased GLUT4 translocation efficiency. Thus, special attention is being paid to search for compounds that are able to enhance this translocation process in the absence of insulin. Experimental Approach Total internal reflection fluorescence (TIRF) microscopy was applied to quantify GLUT4 translocation in highly insulin-sensitive CHO-K1 cells expressing a GLUT4-myc-GFP fusion protein. Key Results Using our approach, we demonstrated GLUT4 translocation modulatory properties of selected substances and identified novel potential insulin mimetics. An increase in the TIRF signal was found to correlate with an elevated glucose uptake. Variations in the expression level of the human insulin receptor (hInsR) showed that the insulin mimetics identified stimulate GLUT4 translocation by a mechanism that is independent of the presence of the hInsR. Conclusions and Implications Taken together, the results indicate that TIRF microscopy is an excellent tool for the quantification of GLUT4 translocation and for identifying insulin mimetic drugs.
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Affiliation(s)
- Peter Lanzerstorfer
- School of Engineering and Environmental Sciences, University of Applied Sciences Upper Austria, Wels, Austria
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Development of a new model system to dissect isoform specific Akt signalling in adipocytes. Biochem J 2015; 468:425-34. [PMID: 25856301 PMCID: PMC4604748 DOI: 10.1042/bj20150191] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 04/09/2015] [Indexed: 12/17/2022]
Abstract
Our study describes the development and validation of a new model system that allows for acute control of signalling by specific Akt isoforms. This model system revealed new insights into the role of Akt kinases in glucose transport and adipogenesis. Protein kinase B (Akt) kinases are critical signal transducers mediating insulin action. Genetic studies revealed that Akt1 and Akt2 signalling differentially contribute to sustain lipid and glucose homoeostasis; however Akt isoform-specific effectors remain elusive due to the lack of a suitable model system to mechanistically interrogate Akt isoform-specific signalling. To overcome those technical limitations we developed a novel model system that provides acute and specific control of signalling by Akt isoforms. We generated mutants of Akt1 and Akt2 resistant to the allosteric Akt inhibitor MK-2206. We then developed adipocyte cell lines, in which endogenous Akt1 or Akt2 has been replaced by their corresponding drug-resistant Akt mutant. Treatment of those cells with MK-2206 allowed for acute and specific control of either Akt1 or Akt2 function. Our data showed that Akt1W80A and Akt2W80A mutants are resistant to MK-2206, dynamically regulated by insulin and able to signal to Akt downstream effectors. Analyses of insulin action in this cellular system showed that Akt1 and Akt2 are both able to mediate insulin regulation of the transcription factor forkhead box O1 (FoxO1) and the glucose transporter 4 (GLUT4), revealing a redundant role for these Akt kinases in the control of glucose transport into fat cells. In contrast, Akt1 signalling is uniquely required for adipogenesis, by controlling the mitotic clonal expansion (MCE) of pre-adipocytes that precedes white adipose cell differentiation. Our data provide new insights into the role of Akt kinases in glucose transport and adipogenesis and support our model system as a valuable tool for the biochemical characterization of signalling by specific Akt isoforms.
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Govers R. Molecular mechanisms of GLUT4 regulation in adipocytes. DIABETES & METABOLISM 2014; 40:400-10. [DOI: 10.1016/j.diabet.2014.01.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/24/2014] [Accepted: 01/26/2014] [Indexed: 01/28/2023]
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A naturally occurring GIP receptor variant undergoes enhanced agonist-induced desensitization, which impairs GIP control of adipose insulin sensitivity. Mol Cell Biol 2014; 34:3618-29. [PMID: 25047836 DOI: 10.1128/mcb.00256-14] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Glucose-dependent insulinotropic polypeptide (GIP), an incretin hormone secreted from gastrointestinal K cells in response to food intake, has an important role in the control of whole-body metabolism. GIP signals through activation of the GIP receptor (GIPR), a G-protein-coupled receptor (GPCR). Dysregulation of this pathway has been implicated in the development of metabolic disease. Here we demonstrate that GIPR is constitutively trafficked between the plasma membrane and intracellular compartments of both GIP-stimulated and unstimulated adipocytes. GIP induces a downregulation of plasma membrane GIPR by slowing GIPR recycling without affecting internalization kinetics. This transient reduction in the expression of GIPR in the plasma membrane correlates with desensitization to the effects of GIP. A naturally occurring variant of GIPR (E354Q) associated with an increased incidence of insulin resistance, type 2 diabetes, and cardiovascular disease in humans responds to GIP stimulation with an exaggerated downregulation from the plasma membrane and a delayed recovery of GIP sensitivity following cessation of GIP stimulation. This perturbation in the desensitization-resensitization cycle of the GIPR variant, revealed in studies of cultured adipocytes, may contribute to the link of the E354Q variant to metabolic disease.
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Abstract
GLUT4 is regulated by its intracellular localization. In the absence of insulin, GLUT4 is efficiently retained intracellularly within storage compartments in muscle and fat cells. Upon insulin stimulation (and contraction in muscle), GLUT4 translocates from these compartments to the cell surface where it transports glucose from the extracellular milieu into the cell. Its implication in insulin-regulated glucose uptake makes GLUT4 not only a key player in normal glucose homeostasis but also an important element in insulin resistance and type 2 diabetes. Nevertheless, how GLUT4 is retained intracellularly and how insulin acts on this retention mechanism is largely unclear. In this review, the current knowledge regarding the various molecular processes that govern GLUT4 physiology is discussed as well as the questions that remain.
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Huang G, Buckler-Pena D, Nauta T, Singh M, Asmar A, Shi J, Kim JY, Kandror KV. Insulin responsiveness of glucose transporter 4 in 3T3-L1 cells depends on the presence of sortilin. Mol Biol Cell 2013; 24:3115-22. [PMID: 23966466 PMCID: PMC3784384 DOI: 10.1091/mbc.e12-10-0765] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Insulin-dependent translocation of Glut4 to the plasma membrane of fat and skeletal muscle cells plays the key role in postprandial clearance of blood glucose. In undifferentiated cells, insulin responsiveness of Glut4 depends on the presence of sortilin, whereas sortilin responds to insulin regardless of Glut4 expression. Insulin-dependent translocation of glucose transporter 4 (Glut4) to the plasma membrane of fat and skeletal muscle cells plays the key role in postprandial clearance of blood glucose. Glut4 represents the major cell-specific component of the insulin-responsive vesicles (IRVs). It is not clear, however, whether the presence of Glut4 in the IRVs is essential for their ability to respond to insulin stimulation. We prepared two lines of 3T3-L1 cells with low and high expression of myc7-Glut4 and studied its translocation to the plasma membrane upon insulin stimulation, using fluorescence-assisted cell sorting and cell surface biotinylation. In undifferentiated 3T3-L1 preadipocytes, translocation of myc7-Glut4 was low regardless of its expression levels. Coexpression of sortilin increased targeting of myc7-Glut4 to the IRVs, and its insulin responsiveness rose to the maximal levels observed in fully differentiated adipocytes. Sortilin ectopically expressed in undifferentiated cells was translocated to the plasma membrane regardless of the presence or absence of myc7-Glut4. AS160/TBC1D4 is expressed at low levels in preadipocytes but is induced in differentiation and provides an additional mechanism for the intracellular retention and insulin-stimulated release of Glut4.
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Affiliation(s)
- Guanrong Huang
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118
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29
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Sadacca LA, Bruno J, Wen J, Xiong W, McGraw TE. Specialized sorting of GLUT4 and its recruitment to the cell surface are independently regulated by distinct Rabs. Mol Biol Cell 2013; 24:2544-57. [PMID: 23804653 PMCID: PMC3744946 DOI: 10.1091/mbc.e13-02-0103] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
RAB10 and RAB14 function at sequential steps of insulin-stimulated GLUT4 translocation to the plasma membrane. RAB14 functions upstream of RAB10 in GLUT4 sorting to the specialized transport vesicles, and RAB10 and its GAP protein comprise the main signaling module that regulates the accumulation of GLUT4 transport vesicles at the plasma membrane. Adipocyte glucose uptake in response to insulin is essential for physiological glucose homeostasis: stimulation of adipocytes with insulin results in insertion of the glucose transporter GLUT4 into the plasma membrane and subsequent glucose uptake. Here we establish that RAB10 and RAB14 are key regulators of GLUT4 trafficking that function at independent, sequential steps of GLUT4 translocation. RAB14 functions upstream of RAB10 in the sorting of GLUT4 to the specialized transport vesicles that ferry GLUT4 to the plasma membrane. RAB10 and its GTPase-activating protein (GAP) AS160 comprise the principal signaling module downstream of insulin receptor activation that regulates the accumulation of GLUT4 transport vesicles at the plasma membrane. Although both RAB10 and RAB14 are regulated by the GAP activity of AS160 in vitro, only RAB10 is under the control of AS160 in vivo. Insulin regulation of the pool of RAB10 required for GLUT4 translocation occurs through regulation of AS160, since activation of RAB10 by DENND4C, its GTP exchange factor, does not require insulin stimulation.
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Affiliation(s)
- L Amanda Sadacca
- Department of Biochemistry, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA
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30
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Bogan JS, Rubin BR, Yu C, Löffler MG, Orme CM, Belman JP, McNally LJ, Hao M, Cresswell JA. Endoproteolytic cleavage of TUG protein regulates GLUT4 glucose transporter translocation. J Biol Chem 2012; 287:23932-47. [PMID: 22610098 DOI: 10.1074/jbc.m112.339457] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To promote glucose uptake into fat and muscle cells, insulin causes the translocation of GLUT4 glucose transporters from intracellular vesicles to the cell surface. Previous data support a model in which TUG traps GLUT4-containing vesicles and tethers them intracellularly in unstimulated cells and in which insulin mobilizes this pool of vesicles by releasing this tether. Here we show that TUG undergoes site-specific endoproteolytic cleavage, which separates a GLUT4-binding, N-terminal region of TUG from a C-terminal region previously suggested to bind an intracellular anchor. Cleavage is accelerated by insulin stimulation in 3T3-L1 adipocytes and is highly dependent upon adipocyte differentiation. The N-terminal TUG cleavage product has properties of a novel 18-kDa ubiquitin-like modifier, which we call TUGUL. The C-terminal product is observed at the expected size of 42 kDa and also as a 54-kDa form that is released from membranes into the cytosol. In transfected cells, intact TUG links GLUT4 to PIST and also binds Golgin-160 through its C-terminal region. PIST is an effector of TC10α, a GTPase previously shown to transmit an insulin signal required for GLUT4 translocation, and we show using RNAi that TC10α is required for TUG proteolytic processing. Finally, we demonstrate that a cleavage-resistant form of TUG does not support highly insulin-responsive GLUT4 translocation or glucose uptake in 3T3-L1 adipocytes. Together with previous results, these data support a model whereby insulin stimulates TUG cleavage to liberate GLUT4 storage vesicles from the Golgi matrix, which promotes GLUT4 translocation to the cell surface and enhances glucose uptake.
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Affiliation(s)
- Jonathan S Bogan
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520-8020, USA.
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31
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Nazari H, Khaleghian A, Takahashi A, Harada N, Webster NJG, Nakano M, Kishi K, Ebina Y, Nakaya Y. Cortactin, an actin binding protein, regulates GLUT4 translocation via actin filament remodeling. BIOCHEMISTRY (MOSCOW) 2012; 76:1262-9. [PMID: 22117553 DOI: 10.1134/s0006297911110083] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Insulin regulates glucose uptake into fat and skeletal muscle cells by modulating the translocation of GLUT4 between the cell surface and interior. We investigated a role for cortactin, a cortical actin binding protein, in the actin filament organization and translocation of GLUT4 in Chinese hamster ovary (CHO-GLUT4myc) and L6-GLUT4myc myotube cells. Overexpression of wild-type cortactin enhanced insulin-stimulated GLUT4myc translocation but did not alter actin fiber formation. Conversely, cortactin mutants lacking the Src homology 3 (SH3) domain inhibited insulin-stimulated formation of actin stress fibers and GLUT4 translocation similar to the actin depolymerizing agent cytochalasin D. Wortmannin, genistein, and a PP1 analog completely blocked insulin-induced Akt phosphorylation, formation of actin stress fibers, and GLUT4 translocation indicating the involvement of both PI3-K/Akt and the Src family of kinases. The effect of these inhibitors was even more pronounced in the presence of overexpressed cortactin suggesting that the same pathways are involved. Knockdown of cortactin by siRNA did not inhibit insulin-induced Akt phosphorylation but completely inhibited actin stress fiber formation and glucose uptake. These results suggest that the actin binding protein cortactin is required for actin stress fiber formation in muscle cells and that this process is absolutely required for translocation of GLUT4-containing vesicles to the plasma membrane.
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Affiliation(s)
- H Nazari
- Department of Nutrition and Metabolism, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Japan
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32
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Zhang Y, Zhang H, Yao XG, Shen H, Chen J, Li C, Chen L, Zheng M, Ye J, Hu L, Shen X, Jiang H. (+)-Rutamarin as a dual inducer of both GLUT4 translocation and expression efficiently ameliorates glucose homeostasis in insulin-resistant mice. PLoS One 2012; 7:e31811. [PMID: 22384078 PMCID: PMC3288053 DOI: 10.1371/journal.pone.0031811] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 01/16/2012] [Indexed: 01/07/2023] Open
Abstract
Glucose transporter 4 (GLUT4) is a principal glucose transporter in response to insulin, and impaired translocation or decreased expression of GLUT4 is believed to be one of the major pathological features of type 2 diabetes mellitus (T2DM). Therefore, induction of GLUT4 translocation or/and expression is a promising strategy for anti-T2DM drug discovery. Here we report that the natural product (+)-Rutamarin (Rut) functions as an efficient dual inducer on both insulin-induced GLUT4 translocation and expression. Rut-treated 3T3-L1 adipocytes exhibit efficiently enhanced insulin-induced glucose uptake, while diet-induced obese (DIO) mice based assays further confirm the Rut-induced improvement of glucose homeostasis and insulin sensitivity in vivo. Subsequent investigation of Rut acting targets indicates that as a specific protein tyrosine phosphatase 1B (PTP1B) inhibitor Rut induces basal GLUT4 translocation to some extent and largely enhances insulin-induced GLUT4 translocation through PI3 kinase-AKT/PKB pathway, while as an agonist of retinoid X receptor α (RXRα), Rut potently increases GLUT4 expression. Furthermore, by using molecular modeling and crystallographic approaches, the possible binding modes of Rut to these two targets have been also determined at atomic levels. All our results have thus highlighted the potential of Rut as both a valuable lead compound for anti-T2DM drug discovery and a promising chemical probe for GLUT4 associated pathways exploration.
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Affiliation(s)
- Yu Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Haitao Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xin-gang Yao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Hong Shen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jing Chen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Chenjing Li
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Lili Chen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Mingyue Zheng
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jiming Ye
- Molecular Pharmacology for Diabetes, School of Health Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Lihong Hu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (LH); (XS); (HJ)
| | - Xu Shen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (LH); (XS); (HJ)
| | - Hualiang Jiang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (LH); (XS); (HJ)
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Mohammad S, Ramos LS, Buck J, Levin LR, Rubino F, McGraw TE. Gastric inhibitory peptide controls adipose insulin sensitivity via activation of cAMP-response element-binding protein and p110β isoform of phosphatidylinositol 3-kinase. J Biol Chem 2011; 286:43062-70. [PMID: 22027830 DOI: 10.1074/jbc.m111.289009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Gastric inhibitory peptide (GIP) is an incretin hormone secreted in response to food intake. The best known function of GIP is to enhance glucose-dependent insulin secretion from pancreatic β-cells. Extra-pancreatic effects of GIP primarily occur in adipose tissues. Here, we demonstrate that GIP increases insulin-dependent translocation of the Glut4 glucose transporter to the plasma membrane and exclusion of FoxO1 transcription factor from the nucleus in adipocytes, establishing that GIP has a general effect on insulin action in adipocytes. Stimulation of adipocytes with GIP alone has no effect on these processes. Using pharmacologic and molecular genetic approaches, we show that the effect of GIP on adipocyte insulin sensitivity requires activation of both the cAMP/protein kinase A/CREB signaling module and p110β phosphoinositol-3' kinase, establishing a novel signal transduction pathway modulating insulin action in adipocytes. This insulin-sensitizing effect is specific for GIP because isoproterenol, which elevates adipocyte cAMP and activates PKA/CREB signaling, does not affect adipocyte insulin sensitivity. The insulin-sensitizing activity points to a more central role for GIP in intestinal regulation of peripheral tissue metabolism, an emerging feature of inter-organ communication in the control of metabolism.
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Affiliation(s)
- Sameer Mohammad
- Department of Biochemistry, Weill Medical College of Cornell University, New York, New York 10065, USA
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34
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Haga Y, Ishii K, Suzuki T. N-glycosylation is critical for the stability and intracellular trafficking of glucose transporter GLUT4. J Biol Chem 2011; 286:31320-7. [PMID: 21757715 DOI: 10.1074/jbc.m111.253955] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The facilitative glucose transporter GLUT4 plays a key role in regulating whole body glucose homeostasis. GLUT4 dramatically changes its distribution upon insulin stimulation, and insulin-resistant diabetes is often linked with compromised translocation of GLUT4 under insulin stimulation. To elucidate the functional significance of the sole N-glycan chain on GLUT4, wild-type GLUT4 and a GLUT4 glycosylation mutant conjugated with enhanced GFP were stably expressed in HeLa cells. The N-glycan contributed to the overall stability of newly synthesized GLUT4. Moreover, cell surface expression of wild-type GLUT4 in HeLa cells was elevated upon insulin treatment, whereas the glycosylation mutant lost the ability to respond to insulin. Subcellular distribution of the mutant was distinct from that of wild-type GLUT4, implying that the subcellular localization required for insulin-mediated translocation was impaired in the mutant protein. Interestingly, kifunensine-treated cells also lost sensitivity to insulin, suggesting the functional importance of the N-glycan structure for GLUT4 trafficking. The K(m) or turnover rates of wild-type and mutant GLUT4, however, were similar, suggesting that the N-glycan had little effect on transporter activity. These findings underscore the critical roles of the N-glycan chain in quality control as well as intracellular trafficking of GLUT4.
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Affiliation(s)
- Yoshimi Haga
- Glycometabolome Team, RIKEN Advanced Science Institute, Wako, Saitama 351-0198, Japan
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Kim HY, Choi HJ, Lim JS, Park EJ, Jung HJ, Lee YJ, Kim SY, Kwon TH. Emerging role of Akt substrate protein AS160 in the regulation of AQP2 translocation. Am J Physiol Renal Physiol 2011; 301:F151-61. [DOI: 10.1152/ajprenal.00519.2010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
AS160, a novel Akt substrate of 160 kDa, contains a Rab GTPase-activating protein (GAP) domain. The present study examined the role of Akt and AS160 in aquaporin-2 (AQP2) trafficking. The main strategy was to examine the changes in AQP2 translocation in response to small interfering RNA (siRNA)-mediated AS160 knockdown in mouse cortical collecting duct cells (M-1 cells and mpkCCDc14 cells). Short-term dDAVP treatment in M-1 cells stimulated phosphorylation of Akt (S473) and AS160, which was also seen in mpkCCDc14 cells. Conversely, the phosphoinositide 3-kinase (PI3K) inhibitor LY 294002 diminished phosphorylation of Akt (S473) and AS160. Moreover, siRNA-mediated Akt1 knockdown was associated with unchanged total AS160 but decreased phospho-AS160 expression, indicating that phosphorylation of AS160 is dependent on PI3K/Akt pathways. siRNA-mediated AS160 knockdown significantly decreased total AS160 and phospho-AS160 expression. Immunocytochemistry revealed that AS160 knockdown in mpkCCDc14 cells was associated with increased AQP2 density in the plasma membrane [135 ± 3% of control mpkCCDc14 cells ( n = 65), P < 0.05, n = 64] despite the absence of dDAVP stimulation. Moreover, cell surface biotinylation assays of mpkCCDc14 cells with AS160 knockdown exhibited significantly higher AQP2 expression [150 ± 15% of control mpkCCDc14 cells ( n = 3), P < 0.05, n = 3]. Taken together, PI3K/Akt pathways mediate the dDAVP-induced AS160 phosphorylation, and AS160 knockdown is associated with higher AQP2 expression in the plasma membrane. Since AS160 contains a GAP domain leading to a decrease in the active GTP-bound form of AS160 target Rab proteins for vesicle trafficking, decreased expression of AS160 is likely to play a role in the translocation of AQP2 to the plasma membrane.
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Affiliation(s)
- Hyo-Young Kim
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
| | - Hyo-Jung Choi
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
| | - Jung-Suk Lim
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
| | - Eui-Jung Park
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
| | - Hyun Jun Jung
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
| | - Yu-Jung Lee
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
| | - Sang-Yeob Kim
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
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Demaegdt H, Gard P, De Backer JP, Lukaszuk A, Szemenyei E, Tóth G, Tourwé D, Vauquelin G. Binding of "AT4 receptor" ligands to insulin regulated aminopeptidase (IRAP) in intact Chinese hamster ovary cells. Mol Cell Endocrinol 2011; 339:34-44. [PMID: 21457753 DOI: 10.1016/j.mce.2011.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/17/2011] [Accepted: 03/22/2011] [Indexed: 01/03/2023]
Abstract
Insulin regulated aminopeptidase (IRAP) recognises "AT(4)-receptor" ligands like angiotensin IV (Ang IV) and peptidomimetics like AL-11. The metabolic stability and high affinity of [(3)H]AL-11 for catalytically active IRAP allowed its detection in Chinese hamster ovary (CHO-K1) cell membranes in the absence of chelators (Demaegdt et al., 2009). Here, we show that, contrary to [(3)H]Ang IV, [(3)H]AL-11 displays high affinity and specificity for IRAP in intact CHO-K1 cells as well. After binding to IRAP at the surface, [(3)H]AL-11 is effectively internalized by an endocytotic process. Unexpectedly, surface binding and internalization of [(3)H]AL-11 was not affected by pretreating the cells with Ang IV but declined with AL-11. In the latter case surface expression of IRAP even increased. After elimination of simpler explanations, it is proposed that metabolically stable "AT(4)-receptor" ligands undergo semi-continuous cycling between the cell surface and endosomal compartments. The in vivo efficacy of stable and unstable "AT(4)-receptor" ligands could therefore differ.
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Affiliation(s)
- Heidi Demaegdt
- Department of Molecular and Biochemical Pharmacology, Research Group of Experimental Pharmacology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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Qu F, Chen Z, Wang X, Meng L, Wu Z, Qu A. Observing GLUT4 translocation in live L6 cells using quantum dots. SENSORS 2011; 11:2077-89. [PMID: 22319399 PMCID: PMC3274056 DOI: 10.3390/s110202077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 12/29/2010] [Accepted: 02/06/2011] [Indexed: 12/30/2022]
Abstract
The glucose transporter 4 (GLUT4) plays a key role in maintaining whole body glucose homeostasis. Tracking GLUT4 in space and time can provide new insights for understanding the mechanisms of insulin-regulated GLUT4 translocation. Organic dyes and fluorescent proteins were used in previous studies for investigating the traffic of GLUT4 in skeletal muscle cells and adipocytes. Because of their relative weak fluorescent signal against strong cellular autofluorescence background and their fast photobleaching rate, most studies only focused on particular segments of GLUT4 traffic. In this study, we have developed a new method for observing the translocation of GLUT4 targeted with photostable and bright quantum dots (QDs) in live L6 cells. QDs were targeted to GLUT4myc specifically and internalized with GLUT4myc through receptor-mediated endocytosis. Compared with traditional fluorescence dyes and fluorescent proteins, QDs with high brightness and extremely photostability are suitable for long-term single particle tracking, so individual GLUT4-QD complex can be easily detected and tracked for long periods of time. This newly described method will be a powerful tool for observing the translocation of GLUT4 in live L6 cells.
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Affiliation(s)
- Feng Qu
- Institute of Biophysics and Biochemistry, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
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38
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Human cytomegalovirus activates glucose transporter 4 expression to increase glucose uptake during infection. J Virol 2010; 85:1573-80. [PMID: 21147915 DOI: 10.1128/jvi.01967-10] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Glucose transport into mammalian cells is mediated by a group of glucose transporters (GLUTs) on the plasma membrane. Human cytomegalovirus (HCMV)-infected human fibroblasts (HFs) demonstrate significantly increased glucose consumption compared to mock-infected cells, suggesting a possible alteration in glucose transport during infection. Inhibition of GLUTs by using cytochalasin B indicated that infected cells utilize GLUT4, whereas normal HFs use GLUT1. Quantitative reverse transcription-PCR and Western analysis confirmed that GLUT4 levels are greatly increased in infected cells. In contrast, GLUT1 was eliminated by a mechanism involving the HCMV major immediate-early protein IE72. The HCMV-mediated induction of GLUT4 circumvents characterized controls of GLUT4 expression that involve serum stimulation, glucose concentration, and nuclear functions of ATP-citrate lyase (ACL). In infected cells the well-characterized Akt-mediated translocation of GLUT4 to the cell surface is also circumvented; GLUT4 localized on the surface of infected cells that were serum starved and had Akt activity inhibited. The significance of GLUT4 induction for the success of HCMV infection was indicated using indinavir, a drug that specifically inhibits glucose uptake by GLUT4. The addition of the drug inhibited glucose uptake in infected cells as well as viral production. Our data show that HCMV-specific mechanisms are used to replace GLUT1, the normal HF GLUT, with GLUT4, the major glucose transporter in adipose tissue, which has a 3-fold-higher glucose transport capacity.
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Jordens I, Molle D, Xiong W, Keller SR, McGraw TE. Insulin-regulated aminopeptidase is a key regulator of GLUT4 trafficking by controlling the sorting of GLUT4 from endosomes to specialized insulin-regulated vesicles. Mol Biol Cell 2010; 21:2034-44. [PMID: 20410133 PMCID: PMC2883947 DOI: 10.1091/mbc.e10-02-0158] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
IRAP is a key regulator of GLUT4 trafficking by controlling sorting from endosomes to specialized insulin-regulated vesicles. Insulin stimulates glucose uptake by regulating translocation of the GLUT4 glucose transporter from intracellular compartments to the plasma membrane. In the absence of insulin GLUT4 is actively sequestered away from the general endosomes into GLUT4-specialized compartments, thereby controlling the amount of GLUT4 at the plasma membrane. Here, we investigated the role of the aminopeptidase IRAP in GLUT4 trafficking. In unstimulated IRAP knockdown adipocytes, plasma membrane GLUT4 levels are elevated because of increased exocytosis, demonstrating an essential role of IRAP in GLUT4 retention. Current evidence supports the model that AS160 RabGAP, which is required for basal GLUT4 retention, is recruited to GLUT4 compartments via an interaction with IRAP. However, here we show that AS160 recruitment to GLUT4 compartments and AS160 regulation of GLUT4 trafficking were unaffected by IRAP knockdown. These results demonstrate that AS160 is recruited to membranes by an IRAP-independent mechanism. Consistent with a role independent of AS160, we showed that IRAP functions in GLUT4 sorting from endosomes to GLUT4-specialized compartments. This is revealed by the relocalization of GLUT4 to endosomes in IRAP knockdown cells. Although IRAP knockdown has profound effects on GLUT4 traffic, GLUT4 knockdown does not affect IRAP trafficking, demonstrating that IRAP traffics independent of GLUT4. In sum, we show that IRAP is both cargo and a key regulator of the insulin-regulated pathway.
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Affiliation(s)
- Ingrid Jordens
- Department of Biochemistry, Weill Medical College of Cornell University, New York, NY 10065, USA
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40
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Xiong W, Jordens I, Gonzalez E, McGraw TE. GLUT4 is sorted to vesicles whose accumulation beneath and insertion into the plasma membrane are differentially regulated by insulin and selectively affected by insulin resistance. Mol Biol Cell 2010; 21:1375-86. [PMID: 20181829 PMCID: PMC2854095 DOI: 10.1091/mbc.e09-08-0751] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
GLUT4 is sorted to vesicles whose accumulation beneath and insertion into the plasma membrane are differentially regulated by insulin and selectively affected by insulin resistance. Insulin stimulates glucose transport by recruiting the GLUT4 glucose transporter to the plasma membrane. Here we use total internal reflection fluorescence microscopy to show that two trafficking motifs of GLUT4, a FQQI motif and a TELE-based motif, target GLUT4 to specialized vesicles that accumulate adjacent to the plasma membrane of unstimulated adipocytes. Mutations of these motifs redistributed GLUT4 to transferrin-containing recycling vesicles adjacent to the plasma membrane, and the degree of redistribution correlated with the increases of the GLUT4 mutants in the plasma membrane of basal adipocytes. These results establish that GLUT4 defaults to recycling endosomes when trafficking to specialized vesicles is disrupted, supporting the hypothesis that the specialized vesicles are derived from an endosomal compartment. Insulin stimulates both the accumulation of GLUT4 in the evanescent field and the fraction of this GLUT4 that is inserted into the plasma membrane. Unexpectedly, these two steps are differentially affected by the development of insulin resistance. We ascribe this selective insulin resistance to inherent differences in the sensitivities of GLUT4 vesicle accumulation and insertion into the plasma membrane to insulin. Differences in insulin sensitivities of various processes may be a general mechanism for the development of the physiologically important phenomenon of selective insulin resistance.
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Affiliation(s)
- Wenyong Xiong
- Department of Biochemistry, Weill Medical College of Cornell University, New York, NY 10065, USA
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41
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Burchfield JG, Lopez JA, Mele K, Vallotton P, Hughes WE. Exocytotic vesicle behaviour assessed by total internal reflection fluorescence microscopy. Traffic 2010; 11:429-39. [PMID: 20070611 DOI: 10.1111/j.1600-0854.2010.01039.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The regulated trafficking or exocytosis of cargo-containing vesicles to the cell surface is fundamental to all cells. By coupling the technology of fluorescently tagged fusion proteins with total internal reflection fluorescence microscopy (TIRFM), it is possible to achieve the high spatio-temporal resolution required to study the dynamics of sub-plasma membrane vesicle trafficking and exocytosis. TIRFM has been used in a number of cell types to visualize and dissect the various steps of exocytosis revealing how molecules identified via genetic and/or biochemical approaches are involved in the regulation of this process. Here, we summarize the contribution of TIRFM to our understanding of the mechanism of exocytosis and discuss the novel methods of analysis that are required to exploit the large volumes of data that can be produced using this technique.
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Affiliation(s)
- James G Burchfield
- The Garvan Institute of Medical Research, 384 Victoria Street, Sydney, New South Wales 2010, Australia
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42
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GLUT4 molecules are recruited at random for insertion within the plasma membrane upon insulin stimulation. FEBS Lett 2009; 584:537-42. [DOI: 10.1016/j.febslet.2009.11.093] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 11/30/2009] [Accepted: 11/30/2009] [Indexed: 01/14/2023]
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43
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Prasad CNV, Anjana T, Banerji A, Gopalakrishnapillai A. Gallic acid induces GLUT4 translocation and glucose uptake activity in 3T3-L1 cells. FEBS Lett 2009; 584:531-6. [PMID: 19962377 DOI: 10.1016/j.febslet.2009.11.092] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 11/16/2009] [Accepted: 11/28/2009] [Indexed: 01/15/2023]
Abstract
GLUT4, a 12 transmembrane protein, plays a major role in insulin mediated glucose transport in muscle and adipocytes. For glucose transport, the GLUT4 protein needs to be translocated to the plasma membrane from the intracellular pool and it is possible that certain compounds may be able to enhance this process. In the present work, we have shown that gallic acid can increase GLUT4 translocation and glucose uptake activity in an Akt-independent but wortmannin-sensitive manner. Further analysis suggested the role of atypical protein kinase Czeta/lambda in gallic acid mediated GLUT4 translocation and glucose uptake.
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Affiliation(s)
- C N Vishnu Prasad
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kollam, Kerala, India
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44
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Zhang Y, Li Y, Guo YW, Jiang HL, Shen X. A sesquiterpene quinone, dysidine, from the sponge Dysidea villosa, activates the insulin pathway through inhibition of PTPases. Acta Pharmacol Sin 2009; 30:333-45. [PMID: 19262557 PMCID: PMC4002405 DOI: 10.1038/aps.2009.5] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Accepted: 01/07/2009] [Indexed: 12/19/2022] Open
Abstract
AIM The sesquiterpene hydroquinones/quinones belong to one class of marine sponge metabolites, and they have received considerable attention due to their varied biological activities, including anti-tumor, anti-HIV, and anti-inflammatory action. In order to probe the potential anti-diabetic effect of the sesquiterpene hydroquinones/quinones, the effect of dysidine on the insulin pathway was studied. METHODS The promotion of glucose uptake by dysidine was studied in differentiated 3T3-L1 cells. The increase in membrane-located GLUT4 by dysidine was studied in CHO-K1/GLUT4 and 3T3-L1 cells by immuno-staining. The activation of the insulin signaling pathway by dysidine was probed by Western blotting. The inhibition of PTPases by dysidine was detected in vitro. RESULTS Dysidine, found in the Hainan sponge Dysidea villosa in the Chinese South Sea, effectively activated the insulin signaling pathway, greatly promoted glucose uptake in 3T3-L1 cells, and showed strong insulin-sensitizing activities. The potential targets of action for dysidine were probed, and the results indicated that dysidine exhibited its cellular effects through activation of the insulin pathway, possibly through the inhibition of protein tyrosine phosphatases, with more specific inhibition against protein tyrosine phosphatase 1B (PTP1B). CONCLUSION Our findings are expected to expand understanding of the biological activities of sesquiterpene hydroquinones/quinones, and they show that dysidine could be a potential lead compound in the development of an alternative adjuvant in insulin therapy.
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Affiliation(s)
- Yu Zhang
- Drug Discovery and Design Centre, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 210203, China
| | - Yan Li
- Drug Discovery and Design Centre, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 210203, China
| | - Yue-wei Guo
- Drug Discovery and Design Centre, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 210203, China
| | - Hua-liang Jiang
- Drug Discovery and Design Centre, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 210203, China
| | - Xu Shen
- Drug Discovery and Design Centre, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 210203, China
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45
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Fazakerley DJ, Lawrence SP, Lizunov VA, Cushman SW, Holman GD. A common trafficking route for GLUT4 in cardiomyocytes in response to insulin, contraction and energy-status signalling. J Cell Sci 2009; 122:727-34. [PMID: 19208760 DOI: 10.1242/jcs.041178] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A new mouse model has been developed to study the localisation and trafficking of the glucose transporter GLUT4 in muscle. The mouse line has specific expression of a GFP and HA-epitope-tagged version of GLUT4 under the control of a muscle-specific promoter. The exofacial HA-tag has enabled fluorescent labelling of only the GLUT4 exposed at the external surface. A distinction between sarcolemma labelling and transverse-tubule labelling has also been possible because the former compartment is much more accessible to intact anti-HA antibody. By contrast, the Fab fragment of the anti-HA antibody could readily detect GLUT4 at the surface of both the sarcolemma and transverse tubules. Here, we have used this mouse model to examine the route taken by cardiomyocyte GLUT4 as it moves to the limiting external membrane surface of sarcolemma and transverse-tubules in response to insulin, contraction or activators of energy-status signalling, including hypoxia. HA-GLUT4-GFP is largely excluded from the sarcolemma and transverse-tubule membrane of cardiomyocytes under basal conditions, but is similarly trafficked to these membrane surfaces after stimulation with insulin, contraction or hypoxia. Internalisation of sarcolemma GLUT4 has been investigated by pulse-labelling surface GLUT4 with intact anti-HA antibody. At early stages of internalisation, HA-tagged GLUT4 colocalises with clathrin at puncta at the sarcolemma, indicating that in cells returning to a basal state, GLUT4 is removed from external membranes by a clathrin-mediated route. We also observed colocalisation of GLUT4 with clathrin under basal conditions. At later stages of internalisation and at steady state, anti-HA antibody labeled-GLUT4 originating from the sarcolemma was predominantly detected in a peri-nuclear compartment, indistinguishable among the specific initial stimuli. These results taken together imply a common pathway for internalisation of GLUT4, independent of the initial stimulus.
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Affiliation(s)
- Daniel J Fazakerley
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
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Rubin BR, Bogan JS. Intracellular retention and insulin-stimulated mobilization of GLUT4 glucose transporters. VITAMINS AND HORMONES 2009; 80:155-92. [PMID: 19251038 DOI: 10.1016/s0083-6729(08)00607-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
GLUT4 glucose transporters are expressed nearly exclusively in adipose and muscle cells, where they cycle to and from the plasma membrane. In cells not stimulated with insulin, GLUT4 is targeted to specialized GLUT4 storage vesicles (GSVs), which sequester it away from the cell surface. Insulin acts within minutes to mobilize these vesicles, translocating GLUT4 to the plasma membrane to enhance glucose uptake. The mechanisms controlling GSV sequestration and mobilization are poorly understood. An insulin-regulated aminopeptidase that cotraffics with GLUT4, IRAP, is required for basal GSV retention and insulin-stimulated mobilization. TUG and Ubc9 bind GLUT4, and likely retain GSVs within unstimulated cells. These proteins may be components of a retention receptor, which sequesters GLUT4 and IRAP away from recycling vesicles. Insulin may then act on this protein complex to liberate GLUT4 and IRAP, discharging GSVs into a recycling pathway for fusion at the cell surface. How GSVs are anchored intracellularly, and how insulin mobilizes these vesicles, are the important topics for ongoing research. Regulation of GLUT4 trafficking is tissue-specific, perhaps in part because the formation of GSVs requires cell type-specific expression of sortilin. Proteins controlling GSV retention and mobilization can then be more widely expressed. Indeed, GLUT4 likely participates in a general mechanism by which the cell surface delivery of various membrane proteins can be controlled by extracellular stimuli. Finally, it is not known if defects in the formation or intracellular retention of GSVs contribute to human insulin resistance, or play a role in the pathogenesis of type 2 diabetes.
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Affiliation(s)
- Bradley R Rubin
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06520-8020, USA
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Lin Z, Zhang Y, Zhang Y, Shen H, Hu L, Jiang H, Shen X. Oleanolic acid derivative NPLC441 potently stimulates glucose transport in 3T3-L1 adipocytes via a multi-target mechanism. Biochem Pharmacol 2008; 76:1251-62. [PMID: 18778688 DOI: 10.1016/j.bcp.2008.08.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 08/11/2008] [Accepted: 08/13/2008] [Indexed: 01/11/2023]
Abstract
The natural product oleanolic acid (OA) has been discovered to exhibit varied pharmacological functions including anti-inflammation, anti-tumor and anti-diabetes, while appropriate synthetic oleanolic acid derivatives seem to possess more potent activities. Here we identified a new oleanolic acid derivative, 3-beta-(2-carboxybenzoyloxy)-oleanolic acid (NPLC441), which functioned as a competitive PTP1B inhibitor and enhanced insulin-stimulated phosphorylation of IR and AKT in HepG2 cells. As an RXRalpha antagonist, it could selectively activate LXRalpha:RXRalpha heterodimer and increase the promoter activities of ABCA1 and ABCG1 genes in transient transfection assays. Quantitative RT-PCR and Western blot analyses suggested that NPLC441 could up-regulate GLUT4 expression in 3T3-L1 adipocytes, and such effect was further proved to be dependent on LXRalpha:RXRalpha activation. Moreover, 2-deoxyglucose uptake technology-based characterization demonstrated that this compound could stimulate glucose uptake in 3T3-L1 adipocytes. Finally, NPLC441 was observed to be able to suppress 11beta-HSD(1) expression in HepG2 cells, following the discovery that activation of LXRalpha:RXRalpha could repress the expression of 11beta-HSD(1). Compared with NPLC441, OA showed no effects on the transactivation of either LXRalpha:RXRalpha heterodimer or RXRalpha-LBD. Our work is thus expected to provide a new insight into the anti-diabetic application for oleanolic acid derivatives via multi-target mechanism, and NPLC441 could be used as a potential lead compound for further research.
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Affiliation(s)
- Zhonghui Lin
- Drug Discovery and Design Centre, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Zhangjiang, Pu Dong, Shanghai 201203, China
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Watson RT, Hou JC, Pessin JE. Recycling of IRAP from the plasma membrane back to the insulin-responsive compartment requires the Q-SNARE syntaxin 6 but not the GGA clathrin adaptors. J Cell Sci 2008; 121:1243-51. [PMID: 18388312 DOI: 10.1242/jcs.017517] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Insulin recruits two transmembrane proteins, GLUT4 and IRAP, to the plasma membrane of muscle cells and adipocytes. The subcellular trafficking and localization of GLUT4, and to a lesser extent IRAP, have been intensely studied, yet the molecular mechanisms responsible for their insulin-responsive compartmentalization remain unknown. Herein we have investigated the endocytosis and recycling of IRAP from the cell surface back to the insulin-responsive compartment (IRC). Our results show that a key dileucine motif at position 76,77 (LL76,77), although required for the initial biosynthetic entry of IRAP into the IRC, is dispensable for entry into the IRC via the endosomal system. Indeed, we found that an AA76,77 mutant of IRAP is fully capable of undergoing endocytosis and is correctly routed back to the IRC. To verify that the AA76,77 mutant enters the bona fide IRC, we show that the internalized IRAP-AA76,77 construct is sequestered in an IRC that is insensitive to brefeldin A yet sensitive to a dominant-interfering mutant of AS160 (AS160-4P). In addition, we show that the GGA clathrin adaptors are not required for the re-entry of IRAP from the cell surface back into the IRC, whereas the Q-SNARE syntaxin 6 is required for this process.
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Affiliation(s)
- Robert T Watson
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
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Blot V, McGraw TE. Molecular mechanisms controlling GLUT4 intracellular retention. Mol Biol Cell 2008; 19:3477-87. [PMID: 18550797 PMCID: PMC2488284 DOI: 10.1091/mbc.e08-03-0236] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In basal adipocytes, glucose transporter 4 (GLUT4) is sequestered intracellularly by an insulin-reversible retention mechanism. Here, we analyze the roles of three GLUT4 trafficking motifs (FQQI, TELEY, and LL), providing molecular links between insulin signaling, cellular trafficking machinery, and the motifs in the specialized trafficking of GLUT4. Our results support a GLUT4 retention model that involves two linked intracellular cycles: one between endosomes and a retention compartment, and the other between endosomes and specialized GLUT4 transport vesicles. Targeting of GLUT4 to the former is dependent on the FQQI motif and its targeting to the latter is dependent on the TELEY motif. These two motifs act independently in retention, with the TELEY-dependent step being under the control of signaling downstream of the AS160 rab GTPase activating protein. Segregation of GLUT4 from endosomes, although positively correlated with the degree of basal retention, does not completely account for GLUT4 retention or insulin-responsiveness. Mutation of the LL motif slows return to basal intracellular retention after insulin withdrawal. Knockdown of clathrin adaptin protein complex-1 (AP-1) causes a delay in the return to intracellular retention after insulin withdrawal. The effects of mutating the LL motif and knockdown of AP-1 were not additive, establishing that AP-1 regulation of GLUT4 trafficking requires the LL motif.
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Affiliation(s)
- Vincent Blot
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
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Demaegdt H, Smitz L, De Backer JP, Le MT, Bauwens M, Szemenyei E, Tóth G, Michotte Y, Vanderheyden P, Vauquelin G. Translocation of the insulin-regulated aminopeptidase to the cell surface: detection by radioligand binding. Br J Pharmacol 2008; 154:872-81. [PMID: 18536739 PMCID: PMC2439846 DOI: 10.1038/bjp.2008.117] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 02/20/2008] [Accepted: 02/27/2008] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Insulin-regulated aminopeptidase (IRAP) and the insulin-dependent glucose transporter GLUT4 colocalize in specific intracellular vesicles (that is, GLUT4 vesicles). These vesicles move slowly to the cell surface, but their translocation is markedly enhanced by insulin, resulting in higher glucose uptake. Previous studies of the insulin-mediated translocation of IRAP to the cell surface have been hampered by the laborious detection of IRAP at the cell surface. We aimed to develop a more direct and faster method to detect IRAP. To this end, we used model systems with well-characterized IRAP: CHO-K1 cells expressing endogenous IRAP and recombinant HEK293 cells expressing human IRAP. A more widespread application of the method was demonstrated by the use of 3T3-L1 adipocytes. EXPERIMENTAL APPROACH After stimulation of the cells with insulin, internalization of IRAP was inhibited by the addition of phenyl arsine oxide (PAO). Then, cell-surface IRAP was detected by the high-affinity binding of radiolabelled angiotensin (Ang) IV (either 125I or 3H). KEY RESULTS We monitored the time- and concentration dependence of insulin-mediated translocation of IRAP in both cell lines and 3T3-L1 adipocytes. A plateau was reached between 6 and 8 min, and 10(-7) M insulin led to the highest amount of IRAP at the cell surface. CONCLUSIONS AND IMPLICATIONS Based on the capacity of the IRAP apoenzyme to display high affinity for radiolabelled Ang IV and on the ability of PAO to inhibit IRAP internalization, we developed a more direct and faster method to measure insulin-mediated translocation of IRAP to the cell surface.
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Affiliation(s)
- H Demaegdt
- Department of Molecular and Biochemical Pharmacology, Vrije Universiteit Brussel, Brussels, Belgium.
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