1
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Geiser A, Foylan S, Tinning PW, Bryant NJ, Gould GW. GLUT4 dispersal at the plasma membrane of adipocytes: a super-resolved journey. Biosci Rep 2023; 43:BSR20230946. [PMID: 37791639 PMCID: PMC10600063 DOI: 10.1042/bsr20230946] [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: 09/07/2023] [Revised: 10/03/2023] [Accepted: 10/04/2023] [Indexed: 10/05/2023] Open
Abstract
In adipose tissue, insulin stimulates glucose uptake by mediating the translocation of GLUT4 from intracellular vesicles to the plasma membrane. In 2010, insulin was revealed to also have a fundamental impact on the spatial distribution of GLUT4 within the plasma membrane, with the existence of two GLUT4 populations at the plasma membrane being defined: (1) as stationary clusters and (2) as diffusible monomers. In this model, in the absence of insulin, plasma membrane-fused GLUT4 are found to behave as clusters. These clusters are thought to arise from exocytic events that retain GLUT4 at their fusion sites; this has been proposed to function as an intermediate hub between GLUT4 exocytosis and re-internalisation. By contrast, insulin stimulation induces the dispersal of GLUT4 clusters into monomers and favours a distinct type of GLUT4-vesicle fusion event, known as fusion-with-release exocytosis. Here, we review how super-resolution microscopy approaches have allowed investigation of the characteristics of plasma membrane-fused GLUT4 and further discuss regulatory step(s) involved in the GLUT4 dispersal machinery, introducing the scaffold protein EFR3 which facilitates localisation of phosphatidylinositol 4-kinase type IIIα (PI4KIIIα) to the cell surface. We consider how dispersal may be linked to the control of transporter activity, consider whether macro-organisation may be a widely used phenomenon to control proteins within the plasma membrane, and speculate on the origin of different forms of GLUT4-vesicle exocytosis.
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Affiliation(s)
- Angéline Geiser
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - Shannan Foylan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - Peter W Tinning
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - Nia J Bryant
- Department of Biology, University of York, Heslington, York, U.K
| | - Gwyn W Gould
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
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2
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Lui A, Patel RS, Krause-Hauch M, Sparks RP, Patel NA. Regulation of Human Sortilin Alternative Splicing by Glucagon-like Peptide-1 (GLP1) in Adipocytes. Int J Mol Sci 2023; 24:14324. [PMID: 37762628 PMCID: PMC10531797 DOI: 10.3390/ijms241814324] [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: 09/01/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
Type 2 diabetes mellitus is a chronic metabolic disease with no cure. Adipose tissue is a major site of systemic insulin resistance. Sortilin is a central component of the glucose transporter -Glut4 storage vesicles (GSV) which translocate to the plasma membrane to uptake glucose from circulation. Here, using human adipocytes we demonstrate the presence of the alternatively spliced, truncated sortilin variant (Sort_T) whose expression is significantly increased in diabetic adipose tissue. Artificial-intelligence-based modeling, molecular dynamics, intrinsically disordered region analysis, and co-immunoprecipitation demonstrated association of Sort_T with Glut4 and decreased glucose uptake in adipocytes. The results show that glucagon-like peptide-1 (GLP1) hormone decreases Sort_T. We deciphered the molecular mechanism underlying GLP1 regulation of alternative splicing of human sortilin. Using splicing minigenes and RNA-immunoprecipitation assays, the results show that GLP1 regulates Sort_T alternative splicing via the splice factor, TRA2B. We demonstrate that targeted antisense oligonucleotide morpholinos reduces Sort_T levels and improves glucose uptake in diabetic adipocytes. Thus, we demonstrate that GLP1 regulates alternative splicing of sortilin in human diabetic adipocytes.
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Affiliation(s)
- Ashley Lui
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA; (A.L.); (M.K.-H.)
| | - Rekha S. Patel
- Research Service, James A. Haley Veterans Hospital, Tampa, FL 33612, USA; (R.S.P.); (R.P.S.)
| | - Meredith Krause-Hauch
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA; (A.L.); (M.K.-H.)
| | - Robert P. Sparks
- Research Service, James A. Haley Veterans Hospital, Tampa, FL 33612, USA; (R.S.P.); (R.P.S.)
- Department of Medicine, Division of Gastroenterology, UMass Chan Medical School, Worcester, MA 01655, USA
| | - Niketa A. Patel
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA; (A.L.); (M.K.-H.)
- Research Service, James A. Haley Veterans Hospital, Tampa, FL 33612, USA; (R.S.P.); (R.P.S.)
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3
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Szczęsny S, Pietrzak P. Exocytotic vesicle fusion classification for early disease diagnosis using a mobile GPU microsystem. Neural Comput Appl 2022. [DOI: 10.1007/s00521-021-06676-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
AbstractThis work addresses monitoring vesicle fusions occurring during the exocytosis process, which is the main way of intercellular communication. Certain vesicle behaviors may also indicate certain precancerous conditions in cells. For this purpose we designed a system able to detect two main types of exocytosis: a full fusion and a kiss-and-run fusion, based on data from multiple amperometric sensors at once. It uses many instances of small perceptron neural networks in a massively parallel manner and runs on Jetson TX2 platform, which uses a GPU for parallel processing. Based on performed benchmarking, approximately 140,000 sensors can be processed in real time within the sensor sampling period equal to 10 ms and an accuracy of 99$$\%$$
%
. The work includes an analysis of the system performance with varying neural network sizes, input data sizes, and sampling periods of fusion signals.
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4
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Fazakerley DJ, Koumanov F, Holman GD. GLUT4 On the move. Biochem J 2022; 479:445-462. [PMID: 35147164 PMCID: PMC8883492 DOI: 10.1042/bcj20210073] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 01/11/2022] [Accepted: 01/14/2022] [Indexed: 12/16/2022]
Abstract
Insulin rapidly stimulates GLUT4 translocation and glucose transport in fat and muscle cells. Signals from the occupied insulin receptor are translated into downstream signalling changes in serine/threonine kinases within timescales of seconds, and this is followed by delivery and accumulation of the glucose transporter GLUT4 at the plasma membrane. Kinetic studies have led to realisation that there are distinct phases of this stimulation by insulin. There is a rapid initial burst of GLUT4 delivered to the cell surface from a subcellular reservoir compartment and this is followed by a steady-state level of continuing stimulation in which GLUT4 recycles through a large itinerary of subcellular locations. Here, we provide an overview of the phases of insulin stimulation of GLUT4 translocation and the molecules that are currently considered to activate these trafficking steps. Furthermore, we suggest how use of new experimental approaches together with phospho-proteomic data may help to further identify mechanisms for activation of these trafficking processes.
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Affiliation(s)
- Daniel J Fazakerley
- Metabolic Research Laboratories, Wellcome-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, U.K
| | - Francoise Koumanov
- Department for Health, Centre for Nutrition, Exercise, and Metabolism, University of Bath, Bath, Somerset BA2 7AY, U.K
| | - Geoffrey D Holman
- Department of Biology and Biochemistry, University of Bath, Bath, Somerset BA2 7AY, U.K
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5
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Li J, Zhang Y, Zeng X, Cheng Y, Tang L, Hong D, Yang X. Lycopene ameliorates insulin resistance and increases muscle capillary density in aging via activation of SIRT1. J Nutr Biochem 2021; 99:108862. [PMID: 34530111 DOI: 10.1016/j.jnutbio.2021.108862] [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: 04/20/2020] [Revised: 02/14/2021] [Accepted: 07/25/2021] [Indexed: 11/27/2022]
Abstract
Lycopene (Ly) is a kind of hydrocarbon, which belongs to the family of tetraterpene carotene and exists in red fruits and vegetables. The decrease of capillary density and blood flow with age is a significant reason for the increase of mortality and morbidity. Herein, our study aims to explore the effects of Ly (a bioactive food compound) on vascular aging in vitro and in vivo and its potential mechanisms. The cytological results showed that Ly could promote the proliferation of human umbilical vein endothelial cell (HUVECs) and enhance the ability of HUVECs to form capillary-like structures. Furthermore, the expression of SIRT1 in aged HUVECs was up-regulated. In vivo, aging rats showed signs of insulin resistance and blood vessel damage. Additionally, the capillary density and blood flow were reduced during the vascular aging process in both D-gal-induced and naturally aging muscle. However, when Ly was given, these conditions could be reversed. Simultaneously, the contents of ATP, lactic acid and pyruvic acid were determined, and it was found that Ly could promote angiogenesis by increasing the utilization rate of glucose and promoting energy metabolism. Finally, in the insulin resistance cell model, we knocked down the SIRT1 and administrated with Ly, and found that it couldn't restore insulin transdution. In conclusion, all the data in this study demonstrate that Ly could reactivate SIRT1 and improve insulin resistance, which was a reversible cause of vascular aging.
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Affiliation(s)
- Jing Li
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, P. R. China; Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, P. R. China
| | - Yingjiang Zhang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, P. R. China
| | - Xin Zeng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, P. R. China
| | - Yahong Cheng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, P. R. China
| | - Liu Tang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, P. R. China
| | - Ding Hong
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, P. R. China.
| | - Xiaolong Yang
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, P. R. China.
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6
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Wang S, Liu Y, Crisman L, Wan C, Miller J, Yu H, Shen J. Genetic evidence for an inhibitory role of tomosyn in insulin-stimulated GLUT4 exocytosis. Traffic 2021; 21:636-646. [PMID: 32851733 DOI: 10.1111/tra.12760] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/21/2020] [Accepted: 08/22/2020] [Indexed: 12/11/2022]
Abstract
Exocytosis is a vesicle fusion process driven by soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). A classic exocytic pathway is insulin-stimulated translocation of the glucose transporter type 4 (GLUT4) from intracellular vesicles to the plasma membrane in adipocytes and skeletal muscles. The GLUT4 exocytic pathway plays a central role in maintaining blood glucose homeostasis and is compromised in insulin resistance and type 2 diabetes. A candidate regulator of GLUT4 exocytosis is tomosyn, a soluble protein expressed in adipocytes. Tomosyn directly binds to GLUT4 exocytic SNAREs in vitro but its role in GLUT4 exocytosis was unknown. In this work, we used CRISPR-Cas9 genome editing to delete the two tomosyn-encoding genes in adipocytes. We observed that both basal and insulin-stimulated GLUT4 exocytosis was markedly elevated in the double knockout (DKO) cells. By contrast, adipocyte differentiation and insulin signaling remained intact in the DKO adipocytes. In a reconstituted liposome fusion assay, tomosyn inhibited all the SNARE complexes underlying GLUT4 exocytosis. The inhibitory activity of tomosyn was relieved by NSF and α-SNAP, which act in concert to remove tomosyn from GLUT4 exocytic SNAREs. Together, these studies revealed an inhibitory role for tomosyn in insulin-stimulated GLUT4 exocytosis in adipocytes. We suggest that tomosyn-arrested SNAREs represent a reservoir of fusion capacity that could be harnessed to treat patients with insulin resistance and type 2 diabetes.
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Affiliation(s)
- Shifeng Wang
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA.,Department of Chinese Medicine Information Science, Beijing University of Chinese Medicine, Beijing, China
| | - Yinghui Liu
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Lauren Crisman
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Chun Wan
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Jessica Miller
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Haijia Yu
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Jingshi Shen
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
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7
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Wu L, Lu P, Guo X, Song K, Lyu Y, Bothwell J, Wu J, Hawkins O, Clarke SL, Lucas EA, Smith BJ, Chowanadisai W, Hartson SD, Ritchey JW, Wang W, Medeiros DM, Li S, Lin D. β-carotene oxygenase 2 deficiency-triggered mitochondrial oxidative stress promotes low-grade inflammation and metabolic dysfunction. Free Radic Biol Med 2021; 164:271-284. [PMID: 33453359 PMCID: PMC7946548 DOI: 10.1016/j.freeradbiomed.2021.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/30/2020] [Accepted: 01/03/2021] [Indexed: 02/06/2023]
Abstract
Low-grade inflammation is a critical pathological factor contributing to the development of metabolic disorders. β-carotene oxygenase 2 (BCO2) was initially identified as an enzyme catalyzing carotenoids in the inner mitochondrial membrane. Mutations in BCO2 are associated with inflammation and metabolic disorders in humans, yet the underlying mechanisms remain unknown. Here, we used loss-of-function approaches in mice and cell culture models to investigate the role of BCO2 in inflammation and metabolic dysfunction. We demonstrated decreases in BCO2 mRNA and protein levels and suppression of mitochondrial respiratory complex I proteins and mitochondrial superoxide dismutase levels in the liver of type 2 diabetic human subjects. Deficiency of BCO2 caused disruption of assembly of the mitochondrial respiratory supercomplexes, such as supercomplex III2+IV in mice, and overproduction of superoxide radicals in primary mouse embryonic fibroblasts. Further, deficiency of BCO2 increased protein carbonylation and populations of natural killer cells and M1 macrophages, and decreased populations of T cells, including CD4+ and/or CD8+ in the bone marrow and white adipose tissues. Elevation of plasma inflammatory cytokines and adipose tissue hypertrophy and inflammation were also characterized in BCO2 deficient mice. Moreover, BCO2 deficient mice were more susceptible to high-fat diet-induced obesity and hyperglycemia. Double knockout of BCO2 and leptin receptor genes caused a significantly greater elevation of the fasting blood glucose level in mice at 4 weeks of age, compared to the age- and sex-matched leptin receptor knockout. Finally, administration of Mito-TEMPO, a mitochondrial specific antioxidant attenuated systemic low-grade inflammation induced by BCO2 deficiency. Collectively, these findings suggest that BCO2 is essential for mitochondrial respiration and metabolic homeostasis in mammals. Loss or decreased expression of BCO2 leads to mitochondrial oxidative stress, low-grade inflammation, and the subsequent development of metabolic disorders.
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Affiliation(s)
- Lei Wu
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Peiran Lu
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Xin Guo
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Kun Song
- Department of Microbiology and Immunology, Tulane University, New Orleans, LA, 70112, USA
| | - Yi Lyu
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - James Bothwell
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Jinglong Wu
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Olivia Hawkins
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Stephen L Clarke
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Edralin A Lucas
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Brenda J Smith
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Winyoo Chowanadisai
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Steve D Hartson
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Jerry W Ritchey
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Weiqun Wang
- Department of Food, Nutrition, Dietetics, and Health, Kansas State University, Manhattan, KS, 66506, USA
| | - Denis M Medeiros
- Department of Molecular Biology and Biochemistry, University of Missouri-Kansas City, Kansas City, MO, 64110, USA
| | - Shitao Li
- Department of Microbiology and Immunology, Tulane University, New Orleans, LA, 70112, USA
| | - Dingbo Lin
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA.
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8
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Norris D, Yang P, Shin SY, Kearney AL, Kim HJ, Geddes T, Senior AM, Fazakerley DJ, Nguyen LK, James DE, Burchfield JG. Signaling Heterogeneity is Defined by Pathway Architecture and Intercellular Variability in Protein Expression. iScience 2021; 24:102118. [PMID: 33659881 PMCID: PMC7892930 DOI: 10.1016/j.isci.2021.102118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/07/2021] [Accepted: 01/22/2021] [Indexed: 12/12/2022] Open
Abstract
Insulin's activation of PI3K/Akt signaling, stimulates glucose uptake by enhancing delivery of GLUT4 to the cell surface. Here we examined the origins of intercellular heterogeneity in insulin signaling. Akt activation alone accounted for ~25% of the variance in GLUT4, indicating that additional sources of variance exist. The Akt and GLUT4 responses were highly reproducible within the same cell, suggesting the variance is between cells (extrinsic) and not within cells (intrinsic). Generalized mechanistic models (supported by experimental observations) demonstrated that the correlation between the steady-state levels of two measured signaling processes decreases with increasing distance from each other and that intercellular variation in protein expression (as an example of extrinsic variance) is sufficient to account for the variance in and between Akt and GLUT4. Thus, the response of a population to insulin signaling is underpinned by considerable single-cell heterogeneity that is largely driven by variance in gene/protein expression between cells. Insulin signaling is heterogeneous between cells in the same population The temporal response of signaling components within a cell is highly reproducible Upstream responses (Akt) can only partially predict downstream response (GLUT4) Protein expression variance is a driver of intercellular signaling heterogeneity
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Affiliation(s)
- Dougall Norris
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Pengyi Yang
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia.,Computational Systems Biology Group, Children's Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW 2145, Australia
| | - Sung-Young Shin
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, VIC 3800, Australia.,Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Alison L Kearney
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Hani Jieun Kim
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia.,Computational Systems Biology Group, Children's Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW 2145, Australia
| | - Thomas Geddes
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia.,Computational Systems Biology Group, Children's Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW 2145, Australia
| | - Alistair M Senior
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Daniel J Fazakerley
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia
| | - Lan K Nguyen
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, VIC 3800, Australia.,Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - David E James
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia.,Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia
| | - James G Burchfield
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
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9
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Brumfield A, Chaudhary N, Molle D, Wen J, Graumann J, McGraw TE. Insulin-promoted mobilization of GLUT4 from a perinuclear storage site requires RAB10. Mol Biol Cell 2021; 32:57-73. [PMID: 33175605 PMCID: PMC8098823 DOI: 10.1091/mbc.e20-06-0356] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 10/30/2020] [Accepted: 11/04/2020] [Indexed: 12/05/2022] Open
Abstract
Insulin controls glucose uptake into muscle and fat cells by inducing a net redistribution of glucose transporter 4 (GLUT4) from intracellular storage to the plasma membrane (PM). The TBC1D4-RAB10 signaling module is required for insulin-stimulated GLUT4 translocation to the PM, although where it intersects GLUT4 traffic was unknown. Here we demonstrate that TBC1D4-RAB10 functions to control GLUT4 mobilization from a trans-Golgi network (TGN) storage compartment, establishing that insulin, in addition to regulating the PM proximal effects of GLUT4-containing vesicles docking to and fusion with the PM, also directly regulates the behavior of GLUT4 deeper within the cell. We also show that GLUT4 is retained in an element/domain of the TGN from which newly synthesized lysosomal proteins are targeted to the late endosomes and the ATP7A copper transporter is translocated to the PM by elevated copper. Insulin does not mobilize ATP7A nor does copper mobilize GLUT4, and RAB10 is not required for copper-elicited ATP7A mobilization. Consequently, GLUT4 intracellular sequestration and mobilization by insulin is achieved, in part, through utilizing a region of the TGN devoted to specialized cargo transport in general rather than being specific for GLUT4. Our results define the GLUT4-containing region of the TGN as a sorting and storage site from which different cargo are mobilized by distinct signals through unique molecular machinery.
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Affiliation(s)
| | - Natasha Chaudhary
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Dorothee Molle
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Jennifer Wen
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Johannes Graumann
- Weill Cornell Medical College in Qatar, Education City, 24144 Doha, State of Qatar
| | - 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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10
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Holman GD. Structure, function and regulation of mammalian glucose transporters of the SLC2 family. Pflugers Arch 2020; 472:1155-1175. [PMID: 32591905 PMCID: PMC7462842 DOI: 10.1007/s00424-020-02411-3] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 05/27/2020] [Accepted: 05/29/2020] [Indexed: 12/12/2022]
Abstract
The SLC2 genes code for a family of GLUT proteins that are part of the major facilitator superfamily (MFS) of membrane transporters. Crystal structures have recently revealed how the unique protein fold of these proteins enables the catalysis of transport. The proteins have 12 transmembrane spans built from a replicated trimer substructure. This enables 4 trimer substructures to move relative to each other, and thereby alternately opening and closing a cleft to either the internal or the external side of the membrane. The physiological substrate for the GLUTs is usually a hexose but substrates for GLUTs can include urate, dehydro-ascorbate and myo-inositol. The GLUT proteins have varied physiological functions that are related to their principal substrates, the cell type in which the GLUTs are expressed and the extent to which the proteins are associated with subcellular compartments. Some of the GLUT proteins translocate between subcellular compartments and this facilitates the control of their function over long- and short-time scales. The control of GLUT function is necessary for a regulated supply of metabolites (mainly glucose) to tissues. Pathophysiological abnormalities in GLUT proteins are responsible for, or associated with, clinical problems including type 2 diabetes and cancer and a range of tissue disorders, related to tissue-specific GLUT protein profiles. The availability of GLUT crystal structures has facilitated the search for inhibitors and substrates and that are specific for each GLUT and that can be used therapeutically. Recent studies are starting to unravel the drug targetable properties of each of the GLUT proteins.
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Affiliation(s)
- Geoffrey D Holman
- Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK.
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11
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Abstract
The skeletal muscle is the largest organ in the body, by mass. It is also the regulator of glucose homeostasis, responsible for 80% of postprandial glucose uptake from the circulation. Skeletal muscle is essential for metabolism, both for its role in glucose uptake and its importance in exercise and metabolic disease. In this article, we give an overview of the importance of skeletal muscle in metabolism, describing its role in glucose uptake and the diseases that are associated with skeletal muscle metabolic dysregulation. We focus on the role of skeletal muscle in peripheral insulin resistance and the potential for skeletal muscle-targeted therapeutics to combat insulin resistance and diabetes, as well as other metabolic diseases like aging and obesity. In particular, we outline the possibilities and pitfalls of the quest for exercise mimetics, which are intended to target the molecular mechanisms underlying the beneficial effects of exercise on metabolic disease. We also provide a description of the molecular mechanisms that regulate skeletal muscle glucose uptake, including a focus on the SNARE proteins, which are essential regulators of glucose transport into the skeletal muscle. © 2020 American Physiological Society. Compr Physiol 10:785-809, 2020.
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Affiliation(s)
- Karla E. Merz
- Department of Molecular and Cellular Endocrinology, City of Hope Beckman Research Institute, Duarte, California, USA
- The Irell and Manella Graduate School of Biological Sciences, City of Hope, Duarte, California, USA
| | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, City of Hope Beckman Research Institute, Duarte, California, USA
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12
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Morris S, Geoghegan ND, Sadler JBA, Koester AM, Black HL, Laub M, Miller L, Heffernan L, Simpson JC, Mastick CC, Cooper J, Gadegaard N, Bryant NJ, Gould GW. Characterisation of GLUT4 trafficking in HeLa cells: comparable kinetics and orthologous trafficking mechanisms to 3T3-L1 adipocytes. PeerJ 2020; 8:e8751. [PMID: 32185116 PMCID: PMC7060922 DOI: 10.7717/peerj.8751] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 02/14/2020] [Indexed: 12/18/2022] Open
Abstract
Insulin-stimulated glucose transport is a characteristic property of adipocytes and muscle cells and involves the regulated delivery of glucose transporter (GLUT4)-containing vesicles from intracellular stores to the cell surface. Fusion of these vesicles results in increased numbers of GLUT4 molecules at the cell surface. In an attempt to overcome some of the limitations associated with both primary and cultured adipocytes, we expressed an epitope- and GFP-tagged version of GLUT4 (HA–GLUT4–GFP) in HeLa cells. Here we report the characterisation of this system compared to 3T3-L1 adipocytes. We show that insulin promotes translocation of HA–GLUT4–GFP to the surface of both cell types with similar kinetics using orthologous trafficking machinery. While the magnitude of the insulin-stimulated translocation of GLUT4 is smaller than mouse 3T3-L1 adipocytes, HeLa cells offer a useful, experimentally tractable, human model system. Here, we exemplify their utility through a small-scale siRNA screen to identify GOSR1 and YKT6 as potential novel regulators of GLUT4 trafficking in human cells.
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Affiliation(s)
- Silke Morris
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | | | - Jessica B A Sadler
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | - Anna M Koester
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | | | - Marco Laub
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | - Lucy Miller
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | - Linda Heffernan
- School of Biology & Environmental Science, University College Dublin, Dublin, Ireland
| | - Jeremy C Simpson
- School of Biology & Environmental Science, University College Dublin, Dublin, Ireland
| | | | - Jon Cooper
- School of Engineering, University of Glasgow, Glasgow, UK
| | | | - Nia J Bryant
- Department of Biology, University of York, York, UK
| | - Gwyn W Gould
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
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13
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Wang S, Crisman L, Miller J, Datta I, Gulbranson DR, Tian Y, Yin Q, Yu H, Shen J. Inducible Exoc7/Exo70 knockout reveals a critical role of the exocyst in insulin-regulated GLUT4 exocytosis. J Biol Chem 2019; 294:19988-19996. [PMID: 31740584 PMCID: PMC6937574 DOI: 10.1074/jbc.ra119.010821] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/13/2019] [Indexed: 12/20/2022] Open
Abstract
Insulin promotes glucose uptake by triggering the translocation of glucose transporter type 4 (GLUT4) from intracellular vesicles to the plasma membrane through exocytosis. GLUT4 exocytosis is a vesicle fusion event involving fusion of GLUT4-containing vesicles with the plasma membrane. For GLUT4 vesicle fusion to occur, GLUT4 vesicles must first be tethered to the plasma membrane. A key tethering factor in exocytosis is a heterooctameric protein complex called the exocyst. The role of the exocyst in GLUT4 exocytosis, however, remains incompletely understood. Here we first systematically analyzed data from a genome-scale CRISPR screen in HeLa cells that targeted virtually all known genes in the human genome, including 12 exocyst genes. The screen recovered only a subset of the exocyst genes, including exocyst complex component 7 (Exoc7/Exo70). Other exocyst genes, however, were not isolated in the screen, likely because of functional redundancy. Our findings suggest that selection of an appropriate exocyst gene is critical for genetic studies of exocyst functions. Next we developed an inducible adipocyte genome editing system that enabled Exoc7 gene deletion in adipocytes without interfering with adipocyte differentiation. We observed that insulin-stimulated GLUT4 exocytosis was markedly inhibited in Exoc7 KO adipocytes. Insulin signaling, however, remained intact in these KO cells. These results indicate that the exocyst plays a critical role in insulin-stimulated GLUT4 exocytosis in adipocytes. We propose that the strategy outlined in this work could be instrumental in genetically dissecting other membrane-trafficking pathways in adipocytes.
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Affiliation(s)
- Shifeng Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
- Department of Chinese Medicine Information Science, Beijing University of Chinese Medicine, Beijing 102488, China
| | - Lauren Crisman
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Jessica Miller
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Ishara Datta
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Daniel R Gulbranson
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Yuan Tian
- Department of Biological Sciences and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
| | - Qian Yin
- Department of Biological Sciences and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
| | - Haijia Yu
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Jingshi Shen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
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14
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The SNAP-25 Protein Family. Neuroscience 2019; 420:50-71. [DOI: 10.1016/j.neuroscience.2018.09.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 08/31/2018] [Accepted: 09/14/2018] [Indexed: 01/04/2023]
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15
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Li J, Bai L, Wei F, Zhao J, Wang D, Xiao Y, Yan W, Wei J. Therapeutic Mechanisms of Herbal Medicines Against Insulin Resistance: A Review. Front Pharmacol 2019; 10:661. [PMID: 31258478 PMCID: PMC6587894 DOI: 10.3389/fphar.2019.00661] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 05/23/2019] [Indexed: 12/16/2022] Open
Abstract
Insulin resistance is a condition in which insulin sensitivity is reduced and the insulin signaling pathway is impaired. Although often expressed as an increase in insulin concentration, the disease is characterized by a decrease in insulin action. This increased workload of the pancreas and the consequent decompensation are not only the main mechanisms for the development of type 2 diabetes (T2D), but also exacerbate the damage of metabolic diseases, including obesity, nonalcoholic fatty liver disease, polycystic ovary syndrome, metabolic syndrome, and others. Many clinical trials have suggested the potential role of herbs in the treatment of insulin resistance, although most of the clinical trials included in this review have certain flaws and bias risks in their methodological design, including the generation of randomization, the concealment of allocation, blinding, and inadequate reporting of sample size estimates. These studies involve not only the single-flavored herbs, but also herbal formulas, extracts, and active ingredients. Numerous of in vitro and in vivo studies have pointed out that the role of herbal medicine in improving insulin resistance is related to interventions in various aspects of the insulin signaling pathway. The targets involved in these studies include insulin receptor substrate, phosphatidylinositol 3-kinase, glucose transporter, AMP-activated protein kinase, glycogen synthase kinase 3, mitogen-activated protein kinases, c-Jun-N-terminal kinase, nuclear factor-kappaB, protein tyrosine phosphatase 1B, nuclear factor-E2-related factor 2, and peroxisome proliferator-activated receptors. Improved insulin sensitivity upon treatment with herbal medicine provides considerable prospects for treating insulin resistance. This article reviews studies of the target mechanisms of herbal treatments for insulin resistance.
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Affiliation(s)
- Jun Li
- Department of Endocrinology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China.,Graduate School, Beijing University of Chinese Medicine, Beijing, China
| | - Litao Bai
- Department of Endocrinology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Fan Wei
- Department of Endocrinology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jing Zhao
- Department of Endocrinology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Danwei Wang
- Department of Endocrinology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yao Xiao
- Department of Endocrinology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Weitian Yan
- Department of Endocrinology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Junping Wei
- Department of Endocrinology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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16
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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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17
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Chemical biology probes of mammalian GLUT structure and function. Biochem J 2018; 475:3511-3534. [PMID: 30459202 PMCID: PMC6243331 DOI: 10.1042/bcj20170677] [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: 08/17/2018] [Revised: 10/11/2018] [Accepted: 10/11/2018] [Indexed: 12/14/2022]
Abstract
The structure and function of glucose transporters of the mammalian GLUT family of proteins has been studied over many decades, and the proteins have fascinated numerous research groups over this time. This interest is related to the importance of the GLUTs as archetypical membrane transport facilitators, as key limiters of the supply of glucose to cell metabolism, as targets of cell insulin and exercise signalling and of regulated membrane traffic, and as potential drug targets to combat cancer and metabolic diseases such as type 2 diabetes and obesity. This review focusses on the use of chemical biology approaches and sugar analogue probes to study these important proteins.
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18
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Profile of Dr. Tao Xu. SCIENCE CHINA-LIFE SCIENCES 2018; 61:1310-1311. [PMID: 30421292 DOI: 10.1007/s11427-018-9381-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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The IRE1α-XBP1s pathway promotes insulin-stimulated glucose uptake in adipocytes by increasing PPARγ activity. Exp Mol Med 2018; 50:1-15. [PMID: 30111834 PMCID: PMC6093883 DOI: 10.1038/s12276-018-0131-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/09/2018] [Accepted: 04/20/2018] [Indexed: 01/06/2023] Open
Abstract
The peroxisome proliferator-activated receptor-γ (PPARγ) improves whole-body insulin sensitivity by regulating the adipogenic and metabolic functions of mature adipocytes. We have previously demonstrated that an active splice variant of X-box binding protein 1 (XBP1s) enhances PPARγ expression during adipogenesis. In this study, we investigated the role of XBP1s, particularly with respect to PPARγ, in the mechanisms underlying insulin sensitivity in mature adipocytes. Insulin was able to stimulate XBP1s generation by activating inositol-requiring enzyme 1 (IRE1) α and was also able to increase its transcriptional activity by inducing nuclear translocation. XBP1s also upregulated the levels of phosphorylated IRS1 and AKT, demonstrating a positive feedback regulatory mechanism linking insulin and XBP1s. XBP1s enhanced the expression of fibroblast growth factor 21 and, in turn, increased PPARγ activity, translocation of GLUT4 to the cell surface, and glucose uptake rate in adipocytes. In addition, XBP1s abolished palmitate-induced insulin resistance in adipocytes by increasing adiponectin secretion, repressing the secretion of pro-inflammatory adipokines such as leptin, monocyte chemoattractant protein 1, and tumor necrosis factor α, and decreasing fatty acid release. These findings provide a novel mechanism by which XBP1s stimulate insulin sensitivity in adipocytes through fibroblast growth factor 21 induction and PPARγ activation.
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20
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Tokarz VL, MacDonald PE, Klip A. The cell biology of systemic insulin function. J Cell Biol 2018; 217:2273-2289. [PMID: 29622564 PMCID: PMC6028526 DOI: 10.1083/jcb.201802095] [Citation(s) in RCA: 235] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/21/2018] [Accepted: 03/23/2018] [Indexed: 12/12/2022] Open
Abstract
Insulin is the paramount anabolic hormone, promoting carbon energy deposition in the body. Its synthesis, quality control, delivery, and action are exquisitely regulated by highly orchestrated intracellular mechanisms in different organs or "stations" of its bodily journey. In this Beyond the Cell review, we focus on these five stages of the journey of insulin through the body and the captivating cell biology that underlies the interaction of insulin with each organ. We first analyze insulin's biosynthesis in and export from the β-cells of the pancreas. Next, we focus on its first pass and partial clearance in the liver with its temporality and periodicity linked to secretion. Continuing the journey, we briefly describe insulin's action on the blood vasculature and its still-debated mechanisms of exit from the capillary beds. Once in the parenchymal interstitium of muscle and adipose tissue, insulin promotes glucose uptake into myofibers and adipocytes, and we elaborate on the intricate signaling and vesicle traffic mechanisms that underlie this fundamental function. Finally, we touch upon the renal degradation of insulin to end its action. Cellular discernment of insulin's availability and action should prove critical to understanding its pivotal physiological functions and how their failure leads to diabetes.
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Affiliation(s)
- Victoria L Tokarz
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Patrick E MacDonald
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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21
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Action of Phytochemicals on Insulin Signaling Pathways Accelerating Glucose Transporter (GLUT4) Protein Translocation. Molecules 2018; 23:molecules23020258. [PMID: 29382104 PMCID: PMC6017132 DOI: 10.3390/molecules23020258] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/15/2018] [Accepted: 01/23/2018] [Indexed: 11/17/2022] Open
Abstract
Diabetes is associated with obesity, generally accompanied by a chronic state of oxidative stress and redox imbalances which are implicated in the progression of micro- and macro-complications like heart disease, stroke, dementia, cancer, kidney failure and blindness. All these complications rise primarily due to consistent high blood glucose levels. Insulin and glucagon help to maintain the homeostasis of glucose and lipids through signaling cascades. Pancreatic hormones stimulate translocation of the glucose transporter isoform 4 (GLUT4) from an intracellular location to the cell surface and facilitate the rapid insulin-dependent storage of glucose in muscle and fat cells. Malfunction in glucose uptake mechanisms, primarily contribute to insulin resistance in type 2 diabetes. Plant secondary metabolites, commonly known as phytochemicals, are reported to have great benefits in the management of type 2 diabetes. The role of phytochemicals and their action on insulin signaling pathways through stimulation of GLUT4 translocation is crucial to understand the pathogenesis of this disease in the management process. This review will summarize the effects of phytochemicals and their action on insulin signaling pathways accelerating GLUT4 translocation based on the current literature.
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22
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Xiong M, Huang Y, Liu Y, Huang M, Song G, Ming Q, Ma X, Yang J, Deng S, Wen Y, Shen J, Liu QH, Zhao P, Yang X. Antidiabetic Activity of Ergosterol from Pleurotus Ostreatus in KK-A y Mice with Spontaneous Type 2 Diabetes Mellitus. Mol Nutr Food Res 2018; 62. [PMID: 29080247 DOI: 10.1002/mnfr.201700444] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 10/11/2017] [Indexed: 01/10/2023]
Abstract
SCOPE The number of people with diabetes is increasing rapidly in the world. In the present study, the hypoglycemic activity and potential mechanism of ergosterol (ERG), a phytosterol derived from the edible mushroom Pleurotus ostreatus are investigated in vitro and in vivo. METHODS AND RESULTS ERG is isolated from Pleurotus ostreatus and identified by NMR spectra. The effects of ERG on the glucose uptake, glucose transporter 4 (GLUT4) translocation, GLUT4 expression, and the phosphorylation of AMPK, Akt and PKC in L6 cells are evaluated. ERG enhances glucose uptake and displays a GLUT4 translocation activity with up-regulating GLUT4 expression and phosphorylation of Akt and PKC in L6 cells. In vivo, antidiabetic activity of ERG is examined. The phosphorylation of Akt and PKC in different tissues from KK-Ay mice is assessed. ERG significantly improves insulin resistance and blood lipid indices while reducing fasting blood glucose levels and protecting pancreas and liver in the mice. Moreover, the phosphorylation of Akt and PKC is increased in different tissues. CONCLUSION The results suggest that ERG may be a potential hypoglycemic agent for the treatment of T2DM with the probable mechanism of stimulating GLUT4 translocation and expression modulated by the PI3K/Akt pathway and PKC pathway.
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Affiliation(s)
- Mingrui Xiong
- School of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Yun Huang
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Yajing Liu
- School of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Mi Huang
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Guanjun Song
- School of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Qian Ming
- School of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Xinhua Ma
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Jie Yang
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Shihao Deng
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Yanzhang Wen
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Jinhua Shen
- School of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Qing-Hua Liu
- School of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Ping Zhao
- School of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Xinzhou Yang
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China.,National Demonstration Center for Experimental Ethnopharmacology Education, South-Central University for Nationalities, Wuhan, China
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23
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Dias S, Paredes S, Ribeiro L. Drugs Involved in Dyslipidemia and Obesity Treatment: Focus on Adipose Tissue. Int J Endocrinol 2018; 2018:2637418. [PMID: 29593789 PMCID: PMC5822899 DOI: 10.1155/2018/2637418] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 09/28/2017] [Accepted: 10/11/2017] [Indexed: 12/15/2022] Open
Abstract
Metabolic syndrome can be defined as a state of disturbed metabolic homeostasis characterized by visceral obesity, atherogenic dyslipidemia, arterial hypertension, and insulin resistance. The growing prevalence of metabolic syndrome will certainly contribute to the burden of cardiovascular disease. Obesity and dyslipidemia are main features of metabolic syndrome, and both can present with adipose tissue dysfunction, involved in the pathogenic mechanisms underlying this syndrome. We revised the effects, and underlying mechanisms, of the current approved drugs for dyslipidemia and obesity (fibrates, statins, niacin, resins, ezetimibe, and orlistat; sibutramine; and diethylpropion, phentermine/topiramate, bupropion and naltrexone, and liraglutide) on adipose tissue. Specifically, we explored how these drugs can modulate the complex pathways involved in metabolism, inflammation, atherogenesis, insulin sensitivity, and adipogenesis. The clinical outcomes of adipose tissue modulation by these drugs, as well as differences of major importance for clinical practice between drugs of the same class, were identified. Whether solutions to these issues will be found in further adjustments and combinations between drugs already in use or necessarily in new advances in pharmacology is not known. To better understand the effect of drugs used in dyslipidemia and obesity on adipose tissue not only is challenging for physicians but could also be the next step to tackle cardiovascular disease.
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Affiliation(s)
- Sofia Dias
- Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
| | - Sílvia Paredes
- Department of Endocrinology, Hospital de Braga, 4710-243 Braga, Portugal
- Department of Public Health and Forensic Sciences, and Medical Education, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
| | - Laura Ribeiro
- Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
- Department of Public Health and Forensic Sciences, and Medical Education, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
- I3S-Instituto de Investigação e Inovação em Saúde, University of Porto, 4200-135 Porto, Portugal
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24
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Wasserstrom S, Morén B, Stenkula KG. Total Internal Reflection Fluorescence Microscopy to Study GLUT4 Trafficking. Methods Mol Biol 2018; 1713:151-159. [PMID: 29218524 DOI: 10.1007/978-1-4939-7507-5_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Total internal reflection fluorescence (TIRF) microscopy is a powerful method that allows examination of plasma membrane close events in real time. The last decade, the method has successfully been used to explore GLUT4 translocation in adipocytes. Here, we describe the procedure for studying GLUT4 trafficking using TIRF microscopy in isolated primary adipocytes.
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Affiliation(s)
- Sebastian Wasserstrom
- Department of Experimental Medical Science, Lund University, BMC C11, Lund, 22 184, Sweden
| | - Björn Morén
- Department of Experimental Medical Science, Lund University, BMC C11, Lund, 22 184, Sweden
| | - Karin G Stenkula
- Department of Experimental Medical Science, Lund University, BMC C11, Lund, 22 184, Sweden.
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25
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β-ecdysterone from Cyanotis arachnoidea exerts hypoglycemic effects through activating IRS-1/Akt/GLUT4 and IRS-1/Akt/GLUT2 signal pathways in KK-Ay mice. J Funct Foods 2017. [DOI: 10.1016/j.jff.2017.09.061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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26
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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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27
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Campello RS, Fátima LA, Barreto-Andrade JN, Lucas TF, Mori RC, Porto CS, Machado UF. Estradiol-induced regulation of GLUT4 in 3T3-L1 cells: involvement of ESR1 and AKT activation. J Mol Endocrinol 2017; 59:257-268. [PMID: 28729437 DOI: 10.1530/jme-17-0041] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 07/20/2017] [Indexed: 12/11/2022]
Abstract
Impaired insulin-stimulated glucose uptake involves reduced expression of the GLUT4 (solute carrier family 2 facilitated glucose transporter member 4, SLC2A4 gene). 17β-estradiol (E2) modulates SLC2A4/GLUT4 expression, but the involved mechanisms are unclear. Although E2 exerts biological effects by binding to estrogen receptors 1/2 (ESR1/2), which are nuclear transcriptional factors; extranuclear effects have also been proposed. We hypothesize that E2 regulates GLUT4 through an extranuclear ESR1 mechanism. Thus, we investigated the effects of E2 upon (1) subcellular distribution of ESRs and the proto-oncogene tyrosine-protein kinases (SRC) involvement; (2) serine/threonine-protein kinase (AKT) activation; (3) Slc2a4/GLUT4 expression and (4) GLUT4 subcellular distribution and glucose uptake in 3T3-L1 adipocytes. Differentiated 3T3-L1 adipocytes were cultivated or not with E2 for 24 h, and additionally treated or not with ESR1-selective agonist (PPT), ESR1-selective antagonist (MPP) or selective SRC inhibitor (PP2). Subcellular distribution of ESR1, ESR2 and GLUT4 was analyzed by immunocytochemistry; Slc2a4 mRNA and GLUT4 were quantified by qPCR and Western blotting, respectively; plasma membrane GLUT4 translocation and glucose uptake were analyzed under insulin stimulus for 20 min or not. E2 induced (1) translocation of ESR1, but not of ESR2, from nucleus to plasma membrane and AKT phosphorylation, effects mimicked by PPT and blocked by MPP and PP2; (2) increased Slc2a4/GLUT4 expression and (3) increased insulin-stimulated GLUT4 translocation and glucose uptake. In conclusion, E2 treatment promoted a SRC-mediated nucleus-plasma membrane shuttle of ESR1, and increased AKT phosphorylation, Slc2a4/GLUT4 expression and plasma membrane GLUT4 translocation; consequently, improving insulin-stimulated glucose uptake. These results unravel mechanisms through which estrogen improves insulin sensitivity.
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Affiliation(s)
- Raquel S Campello
- Department of Physiology and BiophysicsInstitute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Luciana A Fátima
- Department of Physiology and BiophysicsInstitute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - João Nilton Barreto-Andrade
- Department of Physiology and BiophysicsInstitute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Thais F Lucas
- Section of Experimental EndocrinologyDepartment of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Rosana C Mori
- Department of Physiology and BiophysicsInstitute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Catarina S Porto
- Section of Experimental EndocrinologyDepartment of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Ubiratan F Machado
- Department of Physiology and BiophysicsInstitute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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28
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Li H, Mao Y, Yin Z, Xu Y. A Hierarchical Convolutional Neural Network for vesicle fusion event classification. Comput Med Imaging Graph 2017; 60:22-34. [PMID: 28669577 DOI: 10.1016/j.compmedimag.2017.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 02/15/2017] [Accepted: 04/05/2017] [Indexed: 11/17/2022]
Abstract
Quantitative analysis of vesicle exocytosis and classification of different modes of vesicle fusion from the fluorescence microscopy are of primary importance for biomedical researches. In this paper, we propose a novel Hierarchical Convolutional Neural Network (HCNN) method to automatically identify vesicle fusion events in time-lapse Total Internal Reflection Fluorescence Microscopy (TIRFM) image sequences. Firstly, a detection and tracking method is developed to extract image patch sequences containing potential fusion events. Then, a Gaussian Mixture Model (GMM) is applied on each image patch of the patch sequence with outliers rejected for robust Gaussian fitting. By utilizing the high-level time-series intensity change features introduced by GMM and the visual appearance features embedded in some key moments of the fusion process, the proposed HCNN architecture is able to classify each candidate patch sequence into three classes: full fusion event, partial fusion event and non-fusion event. Finally, we validate the performance of our method on 9 challenging datasets that have been annotated by cell biologists, and our method achieves better performances when comparing with three previous methods.
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Affiliation(s)
- Haohan Li
- Department of Computer Science, Missouri University of Science and Technology, Rolla 65409, USA.
| | - Yunxiang Mao
- Department of Computer Science, Missouri University of Science and Technology, Rolla 65409, USA.
| | - Zhaozheng Yin
- Department of Computer Science, Missouri University of Science and Technology, Rolla 65409, USA.
| | - Yingke Xu
- Department of Biomedical Engineering, MOE Key Laboratory of Biomedical Engineering, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou 310027, China.
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29
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Zhou X, Shentu P, Xu Y. Spatiotemporal Regulators for Insulin-Stimulated GLUT4 Vesicle Exocytosis. J Diabetes Res 2017; 2017:1683678. [PMID: 28529958 PMCID: PMC5424486 DOI: 10.1155/2017/1683678] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/21/2017] [Accepted: 04/03/2017] [Indexed: 11/30/2022] Open
Abstract
Insulin increases glucose uptake and storage in muscle and adipose cells, which is accomplished through the mobilization of intracellular GLUT4 storage vesicles (GSVs) to the cell surface upon stimulation. Importantly, the dysfunction of insulin-regulated GLUT4 trafficking is strongly linked with peripheral insulin resistance and type 2 diabetes in human. The insulin signaling pathway, key signaling molecules involved, and precise trafficking itinerary of GSVs are largely identified. Understanding the interaction between insulin signaling molecules and key regulatory proteins that are involved in spatiotemporal regulation of GLUT4 vesicle exocytosis is of great importance to explain the pathogenesis of diabetes and may provide new potential therapeutic targets.
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Affiliation(s)
- Xiaoxu Zhou
- Department of Biomedical Engineering, Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou 310027, China
| | - Ping Shentu
- Department of Biomedical Engineering, Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou 310027, China
| | - Yingke Xu
- Department of Biomedical Engineering, Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou 310027, China
- *Yingke Xu:
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30
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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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31
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Xie B, Chen Q, Chen L, Sheng Y, Wang HY, Chen S. The Inactivation of RabGAP Function of AS160 Promotes Lysosomal Degradation of GLUT4 and Causes Postprandial Hyperglycemia and Hyperinsulinemia. Diabetes 2016; 65:3327-3340. [PMID: 27554475 DOI: 10.2337/db16-0416] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 08/16/2016] [Indexed: 11/13/2022]
Abstract
The AS160 (Akt substrate of 160 kDa) is a Rab-GTPase activating protein (RabGAP) with several other functional domains, and its deficiency in mice or human patients lowers GLUT4 protein levels and causes severe insulin resistance. How its deficiency causes diminished GLUT4 proteins remains unknown. We found that the deletion of AS160 decreased GLUT4 levels in a cell/tissue-autonomous manner. Consequently, skeletal muscle-specific deletion of AS160 caused postprandial hyperglycemia and hyperinsulinemia. The pathogenic effects of AS160 deletion are mainly, if not exclusively, due to the loss of its RabGAP function since the RabGAP-inactive AS160R917K mutant mice phenocopied the AS160 knockout mice. The inactivation of RabGAP of AS160 promotes lysosomal degradation of GLUT4, and the inhibition of lysosome function could restore GLUT4 protein levels. Collectively, these findings demonstrate that the RabGAP activity of AS160 maintains GLUT4 protein levels in a cell/tissue-autonomous manner and its inactivation causes lysosomal degradation of GLUT4 and postprandial hyperglycemia and hyperinsulinemia.
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Affiliation(s)
- Bingxian Xie
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing, China
| | - Qiaoli Chen
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing, China
| | - Liang Chen
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing, China
| | - Yang Sheng
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing, China
| | - Hong Yu Wang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing, China
- Collaborative Innovation Center of Genetics and Development, Shanghai, China
| | - Shuai Chen
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing, China
- Collaborative Innovation Center of Genetics and Development, Shanghai, China
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32
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Chanda D, Luiken JJFP, Glatz JFC. Signaling pathways involved in cardiac energy metabolism. FEBS Lett 2016; 590:2364-74. [PMID: 27403883 DOI: 10.1002/1873-3468.12297] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/09/2016] [Accepted: 07/11/2016] [Indexed: 11/09/2022]
Abstract
Various signaling pathways coordinate energy metabolism and contractile function in the heart. Myocardial uptake of long-chain fatty acids largely occurs by facilitated diffusion, involving the membrane-associated protein, CD36. Glucose uptake, the rate-limiting step in glucose utilization, is mediated predominantly by the glucose transporter protein, GLUT4. Insulin and contraction-mediated AMPK signaling each are implicated in tightly regulating these myocardial 'gate-keepers' of energy balance, that is, CD36 and GLUT4. The insulin and AMPK signaling cascades are complex and their cross-talk is only beginning to be understood. Moreover, transcriptional regulation of the CD36 and GLUT4 is significantly understudied. This review focuses on recent advances on the role of these signaling pathways and transcription factors involved in the regulation of CD36 and GLUT4.
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Affiliation(s)
- Dipanjan Chanda
- Department of Genetics and Cell Biology, CARIM School of Cardiovascular Diseases, Maastricht University, The Netherlands
| | - Joost J F P Luiken
- Department of Genetics and Cell Biology, CARIM School of Cardiovascular Diseases, Maastricht University, The Netherlands
| | - Jan F C Glatz
- Department of Genetics and Cell Biology, CARIM School of Cardiovascular Diseases, Maastricht University, The Netherlands
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33
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Short B. Insulin sends SEC16A packing. J Biophys Biochem Cytol 2016. [DOI: 10.1083/jcb.2141if] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Study reveals that a protein known for its role in ER–Golgi transport also controls GLUT4 trafficking in adipocytes.
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34
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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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35
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Gongpan P, Lu Y, Wang F, Xu Y, Xiong W. AS160 controls eukaryotic cell cycle and proliferation by regulating the CDK inhibitor p21. Cell Cycle 2016; 15:1733-41. [PMID: 27152871 DOI: 10.1080/15384101.2016.1183853] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
AS160 (TBC1D4) has been implicated in multiple biological processes. However, the role and the mechanism of action of AS160 in the regulation of cell proliferation remain unclear. In this study, we demonstrated that AS160 knockdown led to blunted cell proliferation in multiple cell types, including fibroblasts and cancer cells. The results of cell cycle analysis showed that these cells were arrested in the G1 phase. Intriguingly, this inhibition of cell proliferation and the cell cycle arrest caused by AS160 depletion were glucose independent. Moreover, AS160 silencing led to a marked upregulation of the expression of the cyclin-dependent kinase inhibitor p21. Furthermore, whereas AS160 overexpression resulted in p21 downregulation and rescued the arrested cell cycle in AS160-depeleted cells, p21 silencing rescued the inhibited cell cycle and proliferation in the cells. Thus, our results demonstrated that AS160 regulates glucose-independent eukaryotic cell proliferation through p21-dependent control of the cell cycle, and thereby revealed a molecular mechanism of AS160 modulation of cell cycle and proliferation that is of general physiological significance.
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Affiliation(s)
- Pianchou Gongpan
- a State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany , Chinese Academy of Sciences , Kunming , Yunnan , P.R. China.,b Graduate University of Chinese Academy of Sciences , Beijing , P.R. China
| | - Yanting Lu
- a State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany , Chinese Academy of Sciences , Kunming , Yunnan , P.R. China.,b Graduate University of Chinese Academy of Sciences , Beijing , P.R. China
| | - Fang Wang
- a State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany , Chinese Academy of Sciences , Kunming , Yunnan , P.R. China.,b Graduate University of Chinese Academy of Sciences , Beijing , P.R. China
| | - Yuhui Xu
- a State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany , Chinese Academy of Sciences , Kunming , Yunnan , P.R. China.,b Graduate University of Chinese Academy of Sciences , Beijing , P.R. China
| | - Wenyong Xiong
- a State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany , Chinese Academy of Sciences , Kunming , Yunnan , P.R. China
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36
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Xu Y, Nan D, Fan J, Bogan JS, Toomre D. Optogenetic activation reveals distinct roles of PIP3 and Akt in adipocyte insulin action. J Cell Sci 2016; 129:2085-95. [PMID: 27076519 DOI: 10.1242/jcs.174805] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 03/31/2016] [Indexed: 12/26/2022] Open
Abstract
Glucose transporter 4 (GLUT4; also known as SLC2A4) resides on intracellular vesicles in muscle and adipose cells, and translocates to the plasma membrane in response to insulin. The phosphoinositide 3-kinase (PI3K)-Akt signaling pathway plays a major role in GLUT4 translocation; however, a challenge has been to unravel the potentially distinct contributions of PI3K and Akt (of which there are three isoforms, Akt1-Akt3) to overall insulin action. Here, we describe new optogenetic tools based on CRY2 and the N-terminus of CIB1 (CIBN). We used these 'Opto' modules to activate PI3K and Akt selectively in time and space in 3T3-L1 adipocytes. We validated these tools using biochemical assays and performed live-cell kinetic analyses of IRAP-pHluorin translocation (IRAP is also known as LNPEP and acts as a surrogate marker for GLUT4 here). Strikingly, Opto-PIP3 largely mimicked the maximal effects of insulin stimulation, whereas Opto-Akt only partially triggered translocation. Conversely, drug-mediated inhibition of Akt only partially dampened the translocation response of Opto-PIP3 In spatial optogenetic studies, focal targeting of Akt to a region of the cell marked the sites where IRAP-pHluorin vesicles fused, supporting the idea that local Akt-mediated signaling regulates exocytosis. Taken together, these results indicate that PI3K and Akt play distinct roles, and that PI3K stimulates Akt-independent pathways that are important for GLUT4 translocation.
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Affiliation(s)
- Yingke Xu
- Department of Biomedical Engineering, MOE Key Laboratory of Biomedical Engineering, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou 310027, China Department of Cell Biology, Yale University School of Medicine, New Haven, 06510, USA
| | - Di Nan
- Department of Biomedical Engineering, MOE Key Laboratory of Biomedical Engineering, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou 310027, China
| | - Jiannan Fan
- Department of Biomedical Engineering, MOE Key Laboratory of Biomedical Engineering, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou 310027, China
| | - Jonathan S Bogan
- Department of Cell Biology, Yale University School of Medicine, New Haven, 06510, USA Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520-8020, USA
| | - Derek Toomre
- Department of Cell Biology, Yale University School of Medicine, New Haven, 06510, USA
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Lopez-Sanchez I, Ma GS, Pedram S, Kalogriopoulos N, Ghosh P. GIV/girdin binds exocyst subunit-Exo70 and regulates exocytosis of GLUT4 storage vesicles. Biochem Biophys Res Commun 2015; 468:287-93. [PMID: 26514725 DOI: 10.1016/j.bbrc.2015.10.111] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/21/2015] [Indexed: 10/22/2022]
Abstract
Insulin resistance (IR) is a metabolic disorder characterized by impaired glucose uptake in response to insulin. The current paradigm for insulin signaling centers upon the insulin receptor (InsR) and its substrate IRS1; the latter is believed to be the chief conduit for post-receptor signaling. We recently demonstrated that GIV, a Guanidine Exchange Factor (GEF) for the trimeric G protein, Gαi, is a major hierarchical conduit for the metabolic insulin response. By virtue of its ability to directly bind the InsR, IRS1 and PI3K, GIV enhances the InsR-IRS1-Akt-AS160 (RabGAP) signaling cascade and cellular glucose uptake via its GEF function. Phosphoinhibition of GIV-GEF by the fatty-acid/PKCθ pathway inhibits the cascade and impairs glucose uptake. Here we show that GIV directly and constitutively binds the exocyst complex subunit Exo-70 and also associates with GLUT4-storage vesicles (GSVs) exclusively upon insulin stimulation. Without GIV or its GEF function, membrane association of Exo-70 as well as exocytosis of GSVs in response to insulin are impaired. Thus, GIV is an essential component within the insulin signaling cascade that couples upstream signal transducers within the InsR and G-Protein signaling cascade to downstream vesicular trafficking events within the exocytic pathway. These findings suggest a role of GIV in coordinating key signaling and trafficking events of metabolic insulin response.
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Affiliation(s)
- Inmaculada Lopez-Sanchez
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Gary S Ma
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Shabnam Pedram
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Nicholas Kalogriopoulos
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Pradipta Ghosh
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA; Department of Cell and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA.
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38
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Spatiotemporal detection and analysis of exocytosis reveal fusion "hotspots" organized by the cytoskeleton in endocrine cells. Biophys J 2015; 108:251-60. [PMID: 25606674 DOI: 10.1016/j.bpj.2014.11.3462] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/11/2014] [Accepted: 11/19/2014] [Indexed: 02/07/2023] Open
Abstract
Total internal reflection fluorescence microscope has often been used to study the molecular mechanisms underlying vesicle exocytosis. However, the spatial occurrence of the fusion events within a single cell is not frequently explored due to the lack of sensitive and accurate computer-assisted programs to analyze large image data sets. Here, we have developed an image analysis platform for the nonbiased identification of different types of vesicle fusion events with high accuracy in different cell types. By performing spatiotemporal analysis of stimulus-evoked exocytosis in insulin-secreting INS-1 cells, we statistically prove that individual vesicle fusion events are clustered at hotspots. This spatial pattern disappears upon the disruption of either the actin or the microtubule network; this disruption also severely inhibits evoked exocytosis. By demonstrating that newcomer vesicles are delivered from the cell interior to the surface membrane for exocytosis, we highlight a previously unappreciated mechanism in which the cytoskeleton-dependent transportation of secretory vesicles organizes exocytosis hotspots in endocrine cells.
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39
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Ma GS, Lopez-Sanchez I, Aznar N, Kalogriopoulos N, Pedram S, Midde K, Ciaraldi TP, Henry RR, Ghosh P. Activation of G proteins by GIV-GEF is a pivot point for insulin resistance and sensitivity. Mol Biol Cell 2015; 26:4209-23. [PMID: 26378251 PMCID: PMC4642855 DOI: 10.1091/mbc.e15-08-0553] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 09/11/2015] [Indexed: 11/11/2022] Open
Abstract
A long-held tenet in the field of diabetes is that the tipping point between insulin sensitivity and resistance resides at the level of insulin receptor/insulin receptor substrate–adaptor complexes. Here it is shown that activation of Gαi by GIV/Girdin is a decisive event within the metabolic insulin signaling cascade that reversibly orchestrates insulin sensitivity or resistance. Insulin resistance (IR) is a metabolic disorder characterized by impaired insulin signaling and cellular glucose uptake. The current paradigm for insulin signaling centers upon the insulin receptor (InsR) and its substrate IRS1; the latter is believed to be the sole conduit for postreceptor signaling. Here we challenge that paradigm and show that GIV/Girdin, a guanidine exchange factor (GEF) for the trimeric G protein Gαi, is another major hierarchical conduit for the metabolic insulin response. By virtue of its ability to directly bind InsR, IRS1, and phosphoinositide 3-kinase, GIV serves as a key hub in the immediate postreceptor level, which coordinately enhances the metabolic insulin response and glucose uptake in myotubes via its GEF function. Site-directed mutagenesis or phosphoinhibition of GIV-GEF by the fatty acid/protein kinase C-theta pathway triggers IR. Insulin sensitizers reverse phosphoinhibition of GIV and reinstate insulin sensitivity. We also provide evidence for such reversible regulation of GIV-GEF in skeletal muscles from patients with IR. Thus GIV is an essential upstream component that couples InsR to G-protein signaling to enhance the metabolic insulin response, and impairment of such coupling triggers IR. We also provide evidence that GIV-GEF serves as therapeutic target for exogenous manipulation of physiological insulin response and reversal of IR in skeletal muscles.
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Affiliation(s)
- Gary S Ma
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Inmaculada Lopez-Sanchez
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Nicolas Aznar
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Nicholas Kalogriopoulos
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Shabnam Pedram
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Krishna Midde
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Theodore P Ciaraldi
- Department of Veterans Affairs, VA San Diego Healthcare System, San Diego, CA 92161
| | - Robert R Henry
- Department of Veterans Affairs, VA San Diego Healthcare System, San Diego, CA 92161
| | - Pradipta Ghosh
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093 Department of Veterans Affairs, VA San Diego Healthcare System, San Diego, CA 92161 Department of Cell and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
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Lim CY, Han W. Tropomodulin3 as the link between insulin-activated AKT2 and cortical actin remodeling in preparation of GLUT4 exocytosis. BIOARCHITECTURE 2015; 4:210-4. [PMID: 26280982 DOI: 10.1080/19490992.2015.1031949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
It is well established that insulin-induced remodeling of actin filaments into a cortical mesh is required for insulin-stimulated GLUT4 exocytosis. Akt2 and its downstream effectors play a pivotal role in mediating the translocation and membrane fusion of GLUT4-storage vesicle (GSV). However, the direct downstream effector underlying the event of cortical actin reorganization has not been elucidated. In a recent study in Nature Communications, (1) Lim et al identify Tropomodulin3 (Tmod3) as a downstream target of the Akt2 kinase and describe the role of this pointed-end actin-capping protein in regulating insulin-dependent exocytosis of GSVs in adipocytes through the remodeling of the cortical actin network. Phosphorylation of Tmod3 by Akt2 on Ser71 modulates insulin-induced actin remodeling, a key step for GSV fusion with the plasma membrane (PM). Furthermore, the authors establish Tm5NM1 (Tpm3.1 in new nomenclature) (2) as the cognate tropomyosin partner of Tmod3, and an essential role of Tmod3-Tm5NM1 interaction for GSV exocytosis and glucose uptake. This study elucidates a novel effector of Akt2 that provides a direct mechanistic link between Akt2 signaling and actin reorganization essential for vesicle fusion, and suggests that a subset of actin filaments with specific molecular compositions may be dedicated for the process of vesicle fusion.
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Affiliation(s)
- Chun-Yan Lim
- a Laboratory of Metabolic Medicine; Singapore Bioimaging Consortium ; Agency for Science; Technology and Research ; Singapore , Republic of Singapore
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41
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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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Yang X, Yang J, Xu C, Huang M, Zhou Q, Lv J, Ma X, Ke C, Ye Y, Shu G, Zhao P. Antidiabetic effects of flavonoids from Sophora flavescens EtOAc extract in type 2 diabetic KK-ay mice. JOURNAL OF ETHNOPHARMACOLOGY 2015; 171:161-70. [PMID: 26051831 DOI: 10.1016/j.jep.2015.05.043] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 04/22/2015] [Accepted: 05/27/2015] [Indexed: 05/14/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Bitter and cold Chinese medicines have been long used for the treatment for diabetes mellitus (DM) for thousands of years in China. The roots of Sophora flavescens Ait., one of bitter and cold Chinese medicines commonly used to remove lung heat have been used to counteract DM and exerted good clinical effects for diabetic patients in some folk hospitals in Fujian province, PR China. However, the corresponding active principles and antidiabetic mechanism of this Traditional Chinese Medicine remain unclear. Therefore, in this study, we aim at chemical profiling of the active principles, validating the potential antidiabetic effects of the active EtOAc extract (SF-EtOAc) in vitro and in vivo, and elucidating its probable antidiabetic mechanism as well as evaluating its acute oral toxicity. MATERIALS AND METHODS An off-line semi-preparative LC-NMR and LC-UV-ESI MS protocol was developed to determine the chemical principles of the active EtOAc extract rapidly and unambiguously. The effect of SF-EtOAc on the glucose transporter type 4 (GLUT4) translocation in L6 myotubes was examined. T2DM KK-Ay mice were induced by high-fat diet. SF-EtOAc was orally administration at the dose of 30, 60 and 120 mg/kg/d, for 21 days. Metformin was used as positive control. Body weight, plasma glucose, oral glucose tolerance test, serum insulin and blood-lipid indexes were measured. Phosphorylation of the AMP-activated protein kinase (AMPK) expression in liver was measured. RESULTS We found that SF-EtOAc significantly improved oral glucose tolerance, increased serum high density lipoprotein cholesterol (HDL-C) and reduced body weight, blood glucose levels and other related blood-lipid indexes. Mechanistically, SF-EtOAc elevated phosphorylation of AMP-activated protein kinase (AMPK) and stimulated membrane translocation of GLUT4. Moreover, it was unveiled that oral median lethal dose (LD50) of SF-EtOAc was more than 7500 mg/kg, suggesting that SF-EtOAc was practically non-toxic for mice. CONCLUSIONS SF-EtOAc improves glucose tolerance, reduces hyperglycemia and resumes insulin levels, at least in part, by activating GLUT4 translocation which may be modulated by AMPK pathway. According to the results of the present study, SF-EtOAc possesses a potent antidiabetic activity and could be used as a safe remedy for the treatment of diabetes.
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MESH Headings
- Animals
- Blood Glucose/analysis
- Cell Line
- Cholesterol/blood
- Cholesterol/metabolism
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Diet, High-Fat
- Fatty Acids, Nonesterified/blood
- Fatty Acids, Nonesterified/metabolism
- Female
- Flavonoids/pharmacology
- Flavonoids/therapeutic use
- Flavonoids/toxicity
- Glucose/metabolism
- Glucose Tolerance Test
- Hypoglycemic Agents/pharmacology
- Hypoglycemic Agents/therapeutic use
- Hypoglycemic Agents/toxicity
- Insulin/blood
- Insulin/metabolism
- Liver/drug effects
- Liver/metabolism
- Liver/pathology
- Male
- Mice
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Pancreas/drug effects
- Pancreas/pathology
- Phytotherapy
- Plant Roots
- Rats
- Sophora
- Triglycerides/blood
- Triglycerides/metabolism
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Affiliation(s)
- Xinzhou Yang
- College of Pharmacy, South-Central University for Nationalities, 182 Min-Zu Road, Wuhan 430074, PR China; State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu-Chong-Zhi Road, Shanghai 201201, PR China
| | - Jing Yang
- College of Pharmacy, South-Central University for Nationalities, 182 Min-Zu Road, Wuhan 430074, PR China
| | - Chan Xu
- College of Pharmacy, South-Central University for Nationalities, 182 Min-Zu Road, Wuhan 430074, PR China
| | - Mi Huang
- College of Pharmacy, South-Central University for Nationalities, 182 Min-Zu Road, Wuhan 430074, PR China
| | - Qi Zhou
- College of Pharmacy, South-Central University for Nationalities, 182 Min-Zu Road, Wuhan 430074, PR China
| | - Jingnan Lv
- College of Pharmacy, South-Central University for Nationalities, 182 Min-Zu Road, Wuhan 430074, PR China
| | - Xinhua Ma
- College of Pharmacy, South-Central University for Nationalities, 182 Min-Zu Road, Wuhan 430074, PR China
| | - Changqiang Ke
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu-Chong-Zhi Road, Shanghai 201201, PR China
| | - Yang Ye
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu-Chong-Zhi Road, Shanghai 201201, PR China
| | - Guangwen Shu
- College of Pharmacy, South-Central University for Nationalities, 182 Min-Zu Road, Wuhan 430074, PR China.
| | - Ping Zhao
- College of Pharmacy, South-Central University for Nationalities, 182 Min-Zu Road, Wuhan 430074, PR China.
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Koumanov F, Pereira VJ, Richardson JD, Sargent SL, Fazakerley DJ, Holman GD. Insulin regulates Rab3-Noc2 complex dissociation to promote GLUT4 translocation in rat adipocytes. Diabetologia 2015; 58:1877-86. [PMID: 26024738 PMCID: PMC4499112 DOI: 10.1007/s00125-015-3627-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 04/21/2015] [Indexed: 01/10/2023]
Abstract
AIMS/HYPOTHESIS The glucose transporter GLUT4 is present mainly in insulin-responsive tissues of fat, heart and skeletal muscle and is translocated from intracellular membrane compartments to the plasma membrane (PM) upon insulin stimulation. The transit of GLUT4 to the PM is known to be dependent on a series of Rab proteins. However, the extent to which the activity of these Rabs is regulated by the action of insulin action is still unknown. We sought to identify insulin-activated Rab proteins and Rab effectors that facilitate GLUT4 translocation. METHODS We developed a new photoaffinity reagent (Bio-ATB-GTP) that allows GTP-binding proteomes to be explored. Using this approach we screened for insulin-responsive GTP loading of Rabs in primary rat adipocytes. RESULTS We identified Rab3B as a new candidate insulin-stimulated G-protein in adipocytes. Using constitutively active and dominant negative mutants and Rab3 knockdown we provide evidence that Rab3 isoforms are key regulators of GLUT4 translocation in adipocytes. Insulin-stimulated Rab3 GTP binding is associated with disruption of the interaction between Rab3 and its negative effector Noc2. Disruption of the Rab3-Noc2 complex leads to displacement of Noc2 from the PM. This relieves the inhibitory effect of Noc2, facilitating GLUT4 translocation. CONCLUSIONS/INTERPRETATION The discovery of the involvement of Rab3 and Noc2 in an insulin-regulated step in GLUT4 translocation suggests that the control of this translocation process is unexpectedly similar to regulated secretion and particularly pancreatic insulin-vesicle release.
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Affiliation(s)
- Francoise Koumanov
- />Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY UK
| | - Vinit J. Pereira
- />Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY UK
| | | | - Samantha L. Sargent
- />Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY UK
| | - Daniel J. Fazakerley
- />Charles Perkins Centre, School of Molecular Bioscience, The University of Sydney, Sydney, NSW Australia
| | - Geoffrey D. Holman
- />Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY UK
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44
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Abstract
NUCKS regulates genes involved in insulin signalling and loss of NUCKS in vivo leads to insulin resistance and obesity. We report here the specificity of NUCKS in hypothalamus to regulate hypothalamic insulin signalling and peripheral glucose homoeostasis.
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45
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Automatically Identifying Fusion Events between GLUT4 Storage Vesicles and the Plasma Membrane in TIRF Microscopy Image Sequences. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2015; 2015:610482. [PMID: 26089970 PMCID: PMC4452347 DOI: 10.1155/2015/610482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/02/2015] [Accepted: 01/03/2015] [Indexed: 11/18/2022]
Abstract
Quantitative analysis of the dynamic behavior about membrane-bound secretory vesicles has proven to be important in biological research. This paper proposes a novel approach to automatically identify the elusive fusion events between VAMP2-pHluorin labeled GLUT4 storage vesicles (GSVs) and the plasma membrane. The differentiation is implemented to detect the initiation of fusion events by modified forward subtraction of consecutive frames in the TIRFM image sequence. Spatially connected pixels in difference images brighter than a specified adaptive threshold are grouped into a distinct fusion spot. The vesicles are located at the intensity-weighted centroid of their fusion spots. To reveal the true in vivo nature of a fusion event, 2D Gaussian fitting for the fusion spot is used to derive the intensity-weighted centroid and the spot size during the fusion process. The fusion event and its termination can be determined according to the change of spot size. The method is evaluated on real experiment data with ground truth annotated by expert cell biologists. The evaluation results show that it can achieve relatively high accuracy comparing favorably to the manual analysis, yet at a small fraction of time.
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46
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Kioumourtzoglou D, Pryor PR, Gould GW, Bryant NJ. Alternative routes to the cell surface underpin insulin-regulated membrane trafficking of GLUT4. J Cell Sci 2015; 128:2423-9. [PMID: 26071524 PMCID: PMC4510850 DOI: 10.1242/jcs.166561] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 05/26/2015] [Indexed: 01/12/2023] Open
Abstract
Insulin-stimulated delivery of glucose transporters (GLUT4, also known as SLC2A4) from specialized intracellular GLUT4 storage vesicles (GSVs) to the surface of fat and muscle cells is central to whole-body glucose regulation. This translocation and subsequent internalization of GLUT4 back into intracellular stores transits through numerous small membrane-bound compartments (internal GLUT4-containing vesicles; IGVs) including GSVs, but the function of these different compartments is not clear. Cellugyrin (also known as synaptogyrin-2) and sortilin define distinct populations of IGV; sortilin-positive IGVs represent GSVs, but the function of cellugyrin-containing IGVs is unknown. Here, we demonstrate a role for cellugyrin in intracellular sequestration of GLUT4 in HeLa cells and have used a proximity ligation assay to follow changes in pairwise associations between cellugyrin, sortilin, GLUT4 and membrane trafficking machinery following insulin-stimulation of 3T3-L1 adipoctyes. Our data suggest that insulin stimulates traffic from cellugyrin-containing to sortilin-containing membranes, and that cellugyrin-containing IGVs provide an insulin-sensitive reservoir to replenish GSVs following insulin-stimulated exocytosis of GLUT4. Furthermore, our data support the existence of a pathway from cellugyrin-containing membranes to the surface of 3T3-L1 adipocytes that bypasses GSVs under basal conditions, and that insulin diverts traffic away from this into GSVs.
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Affiliation(s)
- Dimitrios Kioumourtzoglou
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK Department of Biology, University of York, York YO10 5DD, UK
| | - Paul R Pryor
- Department of Biology, University of York, York YO10 5DD, UK Centre for Immunology and Infection, Hull York Medical School, University of York, York YO10 5DD, UK
| | - Gwyn W Gould
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Nia J Bryant
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK Department of Biology, University of York, York YO10 5DD, UK
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47
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Glade MJ, Smith K. A glance at … exercise and glucose uptake. Nutrition 2015; 31:893-7. [PMID: 25933500 DOI: 10.1016/j.nut.2014.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 12/03/2014] [Indexed: 10/24/2022]
Affiliation(s)
| | - Kyl Smith
- Progressive Laboratories Inc., Irving, Texas
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48
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Nagano K, Takeuchi H, Gao J, Mori Y, Otani T, Wang D, Hirata M. Tomosyn is a novel Akt substrate mediating insulin-dependent GLUT4 exocytosis. Int J Biochem Cell Biol 2015; 62:62-71. [PMID: 25725259 DOI: 10.1016/j.biocel.2015.02.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 01/31/2015] [Accepted: 02/18/2015] [Indexed: 12/28/2022]
Abstract
Insulin triggers glucose uptake into skeletal muscle and adipose tissues by gaining the available number of glucose transporter 4 (GLUT4) on the cell surface. GLUT4-loaded vesicles are targeted to plasma membrane from the intracellular reservoir through multiple trafficking and fusion processes that are mainly regulated by Akt. However, it is still largely unknown how GLUT4 expression in the cell surface is promoted by insulin. In the present study, we identified tomosyn at Ser-783 as a possible Akt-substrate motif and examined whether the phosphorylation at Ser-783 is involved in the regulation of GLUT4 expression. Both Akt1 and Akt2 phosphorylated the wild-type tomosyn, but not the mutant tomosyn in which Ser-783 was replaced with Ala. Phosphorylation of tomosyn at Ser-783 was also observed in the intact cells by insulin stimulation, which was blocked by PI3K inhibitor, LY294002. In vitro pull-down assay showed that phosphorylation of tomosyn at Ser-783 by Akt inhibited the interaction with syntaxin 4. Insulin stimulation increased GLUT4 in the cell surface of CHO-K1 cells to promote glucose uptake, however exogenous expression of the mutant tomosyn attenuated the increase by insulin. These results suggest that Ser-783 of tomosyn is a target of Akt and is implicated in the interaction with syntaxin 4.
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Affiliation(s)
- Koki Nagano
- Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Hiroshi Takeuchi
- Division of Applied Pharmacology, Kyushu Dental University, Kitakyushu 803-8580, Japan.
| | - Jing Gao
- Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Yoshihide Mori
- Section of Oral and Maxillofacial Surgery, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Takahito Otani
- Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
| | - DaGuang Wang
- Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Masato Hirata
- Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
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Manna P, Jain SK. Phosphatidylinositol-3,4,5-triphosphate and cellular signaling: implications for obesity and diabetes. Cell Physiol Biochem 2015; 35:1253-75. [PMID: 25721445 DOI: 10.1159/000373949] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2015] [Indexed: 12/26/2022] Open
Abstract
Phosphatidylinositol-3,4,5-triphosphate (PtdIns(3,4,5)P₃) is one of the most important phosphoinositides and is capable of activating a wide range of proteins through its interaction with their specific binding domains. Localization and activation of these effector proteins regulate a number of cellular functions, including cell survival, proliferation, cytoskeletal rearrangement, intracellular vesicle trafficking, and cell metabolism. Phosphoinositides have been investigated as an important agonist-dependent second messenger in the regulation of diverse physiological events depending upon the phosphorylation status of their inositol group. Dysregulation in formation as well as metabolism of phosphoinositides is associated with various pathophysiological disorders such as inflammation, allergy, cardiovascular diseases, cancer, and metabolic diseases. Recent studies have demonstrated that the impaired metabolism of PtdIns(3,4,5)P₃ is a prime mediator of insulin resistance associated with various metabolic diseases including obesity and diabetes. This review examines the current status of the role of PtdIns(3,4,5)P₃ signaling in the regulation of various cellular functions and the implications of dysregulated PtdIns(3,4,5)P₃ signaling in obesity, diabetes, and their associated complications.
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Affiliation(s)
- Prasenjit Manna
- Department of Pediatrics, Louisiana State University Health Sciences Center, Shreveport, LA, USA
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50
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Sylow L, Møller LLV, Kleinert M, Richter EA, Jensen TE. Stretch-stimulated glucose transport in skeletal muscle is regulated by Rac1. J Physiol 2015; 593:645-56. [PMID: 25416624 DOI: 10.1113/jphysiol.2014.284281] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 11/13/2014] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Rac1 regulates stretch-stimulated (i.e. mechanical stress) glucose transport in muscle. Actin depolymerization decreases stretch-induced glucose transport in skeletal muscle. Rac1 is a required part of the mechanical stress-component of the contraction-stimulus to glucose transport in skeletal muscle. ABSTRACT An alternative to the canonical insulin signalling pathway for glucose transport is muscle contraction/exercise. Mechanical stress is an integrated part of the muscle contraction/relaxation cycle, and passive stretch stimulates muscle glucose transport. However, the signalling mechanism regulating stretch-stimulated glucose transport is not well understood. We recently reported that the actin cytoskeleton regulating GTPase, Rac1, was activated in mouse muscle in response to stretching. Rac1 is a regulator of contraction- and insulin-stimulated glucose transport, however, its role in stretch-stimulated glucose transport and signalling is unknown. We therefore investigated whether stretch-induced glucose transport in skeletal muscle required Rac1 and the actin cytoskeleton. We used muscle-specific inducible Rac1 knockout mice as well as pharmacological inhibitors of Rac1 and the actin cytoskeleton in isolated soleus and extensor digitorum longus muscles. In addition, the role of Rac1 in contraction-stimulated glucose transport during conditions without mechanical load on the muscles was evaluated in loosely hanging muscles and muscles in which cross-bridge formation was blocked by the myosin ATPase inhibitors BTS and Blebbistatin. Knockout as well as pharmacological inhibition of Rac1 reduced stretch-stimulated glucose transport by 30-50% in soleus and extensor digitorum longus muscle. The actin depolymerizing agent latrunculin B similarly decreased glucose transport in response to stretching by 40-50%. Rac1 inhibition reduced contraction-stimulated glucose transport by 30-40% in tension developing muscle but did not affect contraction-stimulated glucose transport in muscles in which force development was prevented. Our findings suggest that Rac1 and the actin cytoskeleton regulate stretch-stimulated glucose transport and that Rac1 is a required part of the mechanical stress-component of the contraction-stimulus to glucose transport in skeletal muscle.
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Affiliation(s)
- Lykke Sylow
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
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