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Kjøbsted R, Wojtaszewski JFP, Treebak JT. Role of AMP-Activated Protein Kinase for Regulating Post-exercise Insulin Sensitivity. ACTA ACUST UNITED AC 2017; 107:81-126. [PMID: 27812978 DOI: 10.1007/978-3-319-43589-3_5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Skeletal muscle insulin resistance precedes development of type 2 diabetes (T2D). As skeletal muscle is a major sink for glucose disposal, understanding the molecular mechanisms involved in maintaining insulin sensitivity of this tissue could potentially benefit millions of people that are diagnosed with insulin resistance. Regular physical activity in both healthy and insulin-resistant individuals is recognized as the single most effective intervention to increase whole-body insulin sensitivity and thereby positively affect glucose homeostasis. A single bout of exercise has long been known to increase glucose disposal in skeletal muscle in response to physiological insulin concentrations. While this effect is identified to be restricted to the previously exercised muscle, the molecular basis for an apparent convergence between exercise- and insulin-induced signaling pathways is incompletely known. In recent years, we and others have identified the Rab GTPase-activating protein, TBC1 domain family member 4 (TBC1D4) as a target of key protein kinases in the insulin- and exercise-activated signaling pathways. Our working hypothesis is that the AMP-activated protein kinase (AMPK) is important for the ability of exercise to insulin sensitize skeletal muscle through TBC1D4. Here, we aim to provide an overview of the current available evidence linking AMPK to post-exercise insulin sensitivity.
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Affiliation(s)
- Rasmus Kjøbsted
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 2200, Copenhagen, Denmark
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Jonas T Treebak
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 2200, Copenhagen, Denmark.
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Chen L, Chen Q, Rong P, Wang HY, Chen S. The energy sensing LKB1-AMPKα1 pathway regulates IGF1 secretion and consequent activation of the IGF1R-PKB pathway in primary hepatocytes. FEBS J 2017; 284:2096-2109. [PMID: 28500773 DOI: 10.1111/febs.14106] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 05/05/2017] [Accepted: 05/10/2017] [Indexed: 12/22/2022]
Abstract
The insulin-like growth factor 1 (IGF1) pathway has been linked with various diseases including diabetes, cancer and aging. In contrast to the well-established regulatory mechanisms controlling IGF1 expression, molecular mechanisms regulating its secretion are not fully understood. The AMP-activated protein kinase (AMPK) is a key energy sensor, and cumulative evidence shows that it is an attractive therapeutic target for treatment of diabetes, cancer and aging. Here we found that deficiency of AMPK promoted IGF1 secretion in mouse primary hepatocytes. Furthermore, we found that AMPKα1 but not AMPKα2 was involved in regulation of IGF1 secretion in mouse primary hepatocytes. Knockout of AMPK caused activation of the IGF1 receptor (IGF1R)-protein kinase B (PKB; also known as Akt) pathway in hepatocytes, which was mediated by hypersecretion of IGF1. Upstream of AMPK, liver kinase B1 (LKB1) was responsible for AMPK-dependent suppression of IGF1 secretion in hepatocytes. Collectively, these findings demonstrate that the energy-sensing LKB1-AMPK pathway regulates IGF1 secretion in mouse primary hepatocytes, which in turn regulates activation of the IGF1R-PKB pathway.
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Affiliation(s)
- Liang Chen
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing University, China
| | - Qiaoli Chen
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing University, China
| | - Ping Rong
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing University, China
| | - Hong Yu Wang
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing University, China
| | - Shuai Chen
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing University, China
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Kido K, Yokokawa T, Ato S, Sato K, Fujita S. Effect of resistance exercise under conditions of reduced blood insulin on AMPKα Ser485/491 inhibitory phosphorylation and AMPK pathway activation. Am J Physiol Regul Integr Comp Physiol 2017; 313:R110-R119. [PMID: 28515080 DOI: 10.1152/ajpregu.00063.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/02/2017] [Accepted: 05/15/2017] [Indexed: 11/22/2022]
Abstract
Insulin stimulates skeletal muscle glucose uptake via activation of the protein kinase B/Akt (Akt) pathway. Recent studies suggest that insulin downregulates AMP-activated protein kinase (AMPK) activity via Ser485/491 phosphorylation of the AMPK α-subunit. Thus lower blood insulin concentrations may induce AMPK signal activation. Acute exercise is one method to stimulate AMPK activation; however, no study has examined the relationship between blood insulin levels and acute resistance exercise-induced AMPK pathway activation. Based on previous findings, we hypothesized that the acute resistance exercise-induced AMPK pathway activation would be augmented by disruptions in insulin secretion through a decrease in AMPKα Ser485/491 inhibitory phosphorylation. To test the hypothesis, 10-wk-old male Sprague-Dawley rats were administered the toxin streptozotocin (STZ; 55 mg/kg) to destroy the insulin secreting β-cells. Three days postinjection, the right gastrocnemius muscle from STZ and control rats was subjected to resistance exercise by percutaneous electrical stimulation. Animals were killed 0, 1, or 3 h later; activation of the Akt/AMPK and downstream pathways in the muscle tissue was analyzed by Western blotting and real-time PCR. Notably, STZ rats showed a significant decrease in basal Akt and AMPKα Ser485/491 phosphorylation, but substantial exercise-induced increases in both AMPKα Thr172 and acetyl-CoA carboxylase (ACC) Ser79 phosphorylation were observed. Although no significant impact on resistance exercise-induced Akt pathway activation or glucose uptake was found, resistance exercise-induced peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1 α (PGC-1α) gene expression was augmented by STZ treatment. Collectively, these data suggest that circulating insulin levels may regulate acute resistance exercise-induced AMPK pathway activation and AMPK-dependent gene expression relating to basal AMPKα Ser485/491 phosphorylation.
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Affiliation(s)
- Kohei Kido
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Takumi Yokokawa
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan; and
| | - Satoru Ato
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Koji Sato
- Graduate School of Human Development and Environment, Kobe University, Kobe, Hyogo, Japan
| | - Satoshi Fujita
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan;
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Khan AS, Frigo DE. A spatiotemporal hypothesis for the regulation, role, and targeting of AMPK in prostate cancer. Nat Rev Urol 2017; 14:164-180. [PMID: 28169991 PMCID: PMC5672799 DOI: 10.1038/nrurol.2016.272] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The 5'-AMP-activated protein kinase (AMPK) is a master regulator of cellular homeostasis. Despite AMPK's known function in physiology, its role in pathological processes such as prostate cancer is enigmatic. However, emerging evidence is now beginning to decode the paradoxical role of AMPK in cancer and, therefore, inform clinicians if - and how - AMPK could be therapeutically targeted. Spatiotemporal regulation of AMPK complexes could be one of the mechanisms that governs this kinase's role in cancer. We hypothesize that different upstream stimuli will activate select subcellular AMPK complexes. This hypothesis is supported by the distinct subcellular locations of the various AMPK subunits. Each of these unique AMPK complexes regulates discrete downstream processes that can be tumour suppressive or oncogenic. AMPK's final biological output is then determined by the weighted net function of these downstream signalling events, influenced by additional prostate-specific signalling.
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Affiliation(s)
- Ayesha S. Khan
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX USA
| | - Daniel E. Frigo
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX USA
- Genomic Medicine Program, The Houston Methodist Research Institute, Houston, TX USA
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Chen Q, Xie B, Zhu S, Rong P, Sheng Y, Ducommun S, Chen L, Quan C, Li M, Sakamoto K, MacKintosh C, Chen S, Wang HY. A Tbc1d1 Ser231Ala-knockin mutation partially impairs AICAR- but not exercise-induced muscle glucose uptake in mice. Diabetologia 2017; 60:336-345. [PMID: 27826658 DOI: 10.1007/s00125-016-4151-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/14/2016] [Indexed: 11/30/2022]
Abstract
AIMS/HYPOTHESIS TBC1D1 (tre-2/USP6, BUB2, cdc16 domain family member 1) is a Rab GTPase-activating protein (RabGAP) that has been implicated in regulating GLUT4 trafficking. TBC1D1 can be phosphorylated by the AMP-activated protein kinase (AMPK) on Ser231, which consequently interacts with 14-3-3 proteins. Given the key role for AMPK in regulating insulin-independent muscle glucose uptake, we hypothesised that TBC1D1-Ser231 phosphorylation and/or 14-3-3 binding may mediate AMPK-governed glucose homeostasis. METHODS Whole-body glucose homeostasis and muscle glucose uptake were assayed in mice bearing a Tbc1d1 Ser231Ala-knockin mutation or harbouring skeletal muscle-specific Ampkα1/α2 (also known as Prkaa1/2) double-knockout mutations in response to an AMPK-activating agent, 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR). Exercise-induced muscle glucose uptake and exercise capacity were also determined in the Tbc1d1 Ser231Ala-knockin mice. RESULTS Skeletal muscle-specific deletion of Ampkα1/a2 in mice prevented AICAR-induced hypoglycaemia and muscle glucose uptake. The Tbc1d1 Ser231Ala-knockin mutation also attenuated the glucose-lowering effect of AICAR in mice. Glucose uptake and cell surface GLUT4 content were significantly lower in muscle isolated from the Tbc1d1 Ser231Ala-knockin mice upon stimulation with a submaximal dose of AICAR. However, this Tbc1d1 Ser231Ala-knockin mutation neither impaired exercise-induced muscle glucose uptake nor affected exercise capacity in mice. CONCLUSIONS/INTERPRETATION TBC1D1-Ser231 phosphorylation and/or 14-3-3 binding partially mediates AMPK-governed glucose homeostasis and muscle glucose uptake in a context-dependent manner.
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Affiliation(s)
- Qiaoli Chen
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Pukou District, Nanjing, 210061, China
| | - Bingxian Xie
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Pukou District, Nanjing, 210061, China
| | - Sangsang Zhu
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Pukou District, Nanjing, 210061, China
| | - Ping Rong
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Pukou District, Nanjing, 210061, China
| | - Yang Sheng
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Pukou District, Nanjing, 210061, China
| | - Serge Ducommun
- Nestlé Institute of Health Sciences SA, Campus EPFL, Quartier de l'Innovation, Bâtiment G, Lausanne, Switzerland
| | - Liang Chen
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Pukou District, Nanjing, 210061, China
| | - Chao Quan
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Pukou District, Nanjing, 210061, China
| | - Min Li
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Pukou District, Nanjing, 210061, China
| | - Kei Sakamoto
- Nestlé Institute of Health Sciences SA, Campus EPFL, Quartier de l'Innovation, Bâtiment G, Lausanne, Switzerland
| | - Carol MacKintosh
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, Scotland, UK
| | - Shuai Chen
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Pukou District, Nanjing, 210061, China.
- Collaborative Innovation Center of Genetics and Development, Shanghai, China.
| | - Hong Yu Wang
- MOE Key Laboratory of Model Animal for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Pukou District, Nanjing, 210061, China.
- Collaborative Innovation Center of Genetics and Development, Shanghai, China.
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Yuan H, Wang T, Niu Y, Liu X, Fu L. AMP-activated protein kinase-mediated expression of heat shock protein beta 1 enhanced insulin sensitivity in the skeletal muscle. FEBS Lett 2016; 591:97-108. [PMID: 27928820 DOI: 10.1002/1873-3468.12516] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 10/18/2016] [Accepted: 11/24/2016] [Indexed: 11/12/2022]
Abstract
Activation of AMP-activated protein kinase (AMPK) has been viewed as an important target for the treatment of insulin resistance. Here, by proteomic analysis, we found that expression of heat shock protein beta-1 (HSPB1) was induced by the AMP analog 5-aminoimidazole-4-carboxamide 1-β-D-ribofuranoside in palmitate-induced insulin-resistant cells. Overexpression of AMPKα2, or activation of AMPKα via acute/chronic exercise training, increased HSPB1 expression in the skeletal muscle. In AMPKα2-/- mice, HSPB1 expression was downregulated in the quadriceps muscles. Exercise did not increase HSPB1 expression in AMPKα2-/- mice. Moreover, overexpression of HSPB1 enhanced insulin sensitivity in palmitate-induced insulin-resistant cells and restored metabolic phenotypes associated with defective AMPK. Finally, HSPB1 was required for AMPK-mediated activation of the class IIa histone deacetylases and glucose uptake in the skeletal muscle. Our results demonstrate that AMPK-mediated HSPB1 expression enhanced insulin sensitivity in the skeletal muscle.
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Affiliation(s)
- Hairui Yuan
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Tianjin Medical University, China.,Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, China
| | - Tianyi Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Tianjin Medical University, China
| | - Yanmei Niu
- Department of Rehabilitation and Sports Medicine, Tianjin Medical University, China
| | - Xiaolei Liu
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Tianjin Medical University, China
| | - Li Fu
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Tianjin Medical University, China
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Jiang J, Gao Y, Hou Y, Li W, Zhang S, Zhang Q, Sun D. Whole-Genome Resequencing of Holstein Bulls for Indel Discovery and Identification of Genes Associated with Milk Composition Traits in Dairy Cattle. PLoS One 2016; 11:e0168946. [PMID: 28030618 PMCID: PMC5193355 DOI: 10.1371/journal.pone.0168946] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 12/08/2016] [Indexed: 11/18/2022] Open
Abstract
The use of whole-genome resequencing to obtain more information on genetic variation could produce a range of benefits for the dairy cattle industry, especially with regard to increasing milk production and improving milk composition. In this study, we sequenced the genomes of eight Holstein bulls from four half- or full-sib families, with high and low estimated breeding values (EBVs) of milk protein percentage and fat percentage at an average effective depth of 10×, using Illumina sequencing. Over 0.9 million nonredundant short insertions and deletions (indels) [1–49 base pairs (bp)] were obtained. Among them, 3,625 indels that were polymorphic between the high and low groups of bulls were revealed and subjected to further analysis. The vast majority (76.67%) of these indels were novel. Follow-up validation assays confirmed that most (70%) of the randomly selected indels represented true variations. The indels that were polymorphic between the two groups were annotated based on the cattle genome sequence assembly (UMD3.1.69); as a result, nearly 1,137 of them were found to be located within 767 annotated genes, only 5 (0.138%) of which were located in exons. Then, by integrated analysis of the 767 genes with known quantitative trait loci (QTL); significant single-nucleotide polymorphisms (SNPs) previously identified by genome-wide association studies (GWASs) to be associated with bovine milk protein and fat traits; and the well-known pathways involved in protein, fat synthesis, and metabolism, we identified a total of 11 promising candidate genes potentially affecting milk composition traits. These were FCGR2B, CENPE, RETSAT, ACSBG2, NFKB2, TBC1D1, NLK, MAP3K1, SLC30A2, ANGPT1 and UGDH. Our findings provide a basis for further study and reveal key genes for milk composition traits in dairy cattle.
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Affiliation(s)
- Jianping Jiang
- Department of Animal Genetics and Breeding, College of Animal Science and Technology, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, China
| | - Yahui Gao
- Department of Animal Genetics and Breeding, College of Animal Science and Technology, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, China
| | - Yali Hou
- Laboratory of Disease Genomics and Individualized Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Wenhui Li
- Department of Animal Genetics and Breeding, College of Animal Science and Technology, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, China
| | - Shengli Zhang
- Department of Animal Genetics and Breeding, College of Animal Science and Technology, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, China
| | - Qin Zhang
- Department of Animal Genetics and Breeding, College of Animal Science and Technology, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, China
| | - Dongxiao Sun
- Department of Animal Genetics and Breeding, College of Animal Science and Technology, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, China
- * E-mail:
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Kim J, Yang G, Ha J. Targeting of AMP-activated protein kinase: prospects for computer-aided drug design. Expert Opin Drug Discov 2016; 12:47-59. [PMID: 27797589 DOI: 10.1080/17460441.2017.1255194] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Dysregulation of energy homeostasis has been implicated in a number of human chronic diseases including diabetes, obesity, cancer, and inflammation. Given the functional attributes as a central regulator of energy homeostasis, AMP-activated protein kinase (AMPK) is emerging as a therapeutic target for these diseases, and lines of evidence have highlighted the need for rational and robust screening systems for identifying specific AMPK modulators with a therapeutic potential for preventing and/or curing these diseases. Areas covered: Here, the authors review the recent advances in the understanding of three-dimensional structures of AMPK in relationship with the regulatory mechanisms, potentials of AMPK as a therapeutic target in human chronic diseases, and prospects of computer-based drug design for AMPK. Expert opinion: Accumulating information of AMPK structure has provided us with deep insight into the molecular basis underlying the regulatory mechanisms, and further discloses several structural domains, which can be served for a target site for computer-based drug design. Molecular docking and simulations provides useful information about the binding sites between potent drugs and AMPK as well as a rational screening format to discover isoform-specific AMPK modulators. For these reasons, the authors suggest that computer-aided virtual screening methods hold promise as a rational approach for discovering more specific AMPK modulators.
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Affiliation(s)
- Joungmok Kim
- a Department of Oral Biochemistry and Molecular Biology, School of Dentistry , Kyung Hee University , Dongdaemun-gu , Republic of Korea
| | - Goowon Yang
- b Department of Biochemistry and Molecular Biology, Graduate School , Kyung Hee University , Seoul , Republic of Korea
| | - Joohun Ha
- b Department of Biochemistry and Molecular Biology, Graduate School , Kyung Hee University , Seoul , Republic of Korea
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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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High Fat Diet-Induced Skeletal Muscle Wasting Is Decreased by Mesenchymal Stem Cells Administration: Implications on Oxidative Stress, Ubiquitin Proteasome Pathway Activation, and Myonuclear Apoptosis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:9047821. [PMID: 27579157 PMCID: PMC4992759 DOI: 10.1155/2016/9047821] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/14/2016] [Indexed: 12/20/2022]
Abstract
Obesity can lead to skeletal muscle atrophy, a pathological condition characterized by the loss of strength and muscle mass. A feature of muscle atrophy is a decrease of myofibrillar proteins as a result of ubiquitin proteasome pathway overactivation, as evidenced by increased expression of the muscle-specific ubiquitin ligases atrogin-1 and MuRF-1. Additionally, other mechanisms are related to muscle wasting, including oxidative stress, myonuclear apoptosis, and autophagy. Stem cells are an emerging therapy in the treatment of chronic diseases such as high fat diet-induced obesity. Mesenchymal stem cells (MSCs) are a population of self-renewable and undifferentiated cells present in the bone marrow and other mesenchymal tissues of adult individuals. The present study is the first to analyze the effects of systemic MSC administration on high fat diet-induced skeletal muscle atrophy in the tibialis anterior of mice. Treatment with MSCs reduced losses of muscle strength and mass, decreases of fiber diameter and myosin heavy chain protein levels, and fiber type transitions. Underlying these antiatrophic effects, MSC administration also decreased ubiquitin proteasome pathway activation, oxidative stress, and myonuclear apoptosis. These results are the first to indicate that systemically administered MSCs could prevent muscle wasting associated with high fat diet-induced obesity and diabetes.
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Disruption of the AMPK-TBC1D1 nexus increases lipogenic gene expression and causes obesity in mice via promoting IGF1 secretion. Proc Natl Acad Sci U S A 2016; 113:7219-24. [PMID: 27307439 DOI: 10.1073/pnas.1600581113] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tre-2/USP6, BUB2, cdc16 domain family member 1 (the TBC domain is the GTPase activating protein domain) (TBC1D1) is a Rab GTPase activating protein that is phosphorylated on Ser(231) by the AMP-activated protein kinase (AMPK) in response to intracellular energy stress. However, the in vivo role and importance of this phosphorylation event remains unknown. To address this question, we generated a mouse model harboring a TBC1D1(Ser231Ala) knockin (KI) mutation and found that the KI mice developed obesity on a normal chow diet. Mechanistically, TBC1D1 is located on insulin-like growth factor 1 (IGF1) storage vesicles, and the KI mutation increases endocrinal and paracrinal/autocrinal IGF1 secretion in an Rab8a-dependent manner. Hypersecretion of IGF1 causes increased expression of lipogenic genes via activating the protein kinase B (PKB; also known as Akt)-mammalian target of rapamycin (mTOR) pathway in adipose tissues, which contributes to the development of obesity, diabetes, and hepatic steatosis as the KI mice age. Collectively, these findings demonstrate that the AMPK-TBC1D1 signaling nexus interacts with the PKB-mTOR pathway via IGF1 secretion, which consequently controls expression of lipogenic genes in the adipose tissue. These findings also have implications for drug discovery to combat obesity.
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Krag TO, Pinós T, Nielsen TL, Duran J, García-Rocha M, Andreu AL, Vissing J. Differential glucose metabolism in mice and humans affected by McArdle disease. Am J Physiol Regul Integr Comp Physiol 2016; 311:R307-14. [PMID: 27280431 DOI: 10.1152/ajpregu.00489.2015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 05/27/2016] [Indexed: 11/22/2022]
Abstract
McArdle disease (muscle glycogenosis type V) is a disease caused by myophosphorylase deficiency leading to "blocked" glycogen breakdown. A significant but varying glycogen accumulation in especially distal hind limb muscles of mice affected by McArdle disease has recently been demonstrated. In this study, we investigated how myophosphorylase deficiency affects glucose metabolism in hind limb muscle of 20-wk-old McArdle mice and vastus lateralis muscles from patients with McArdle disease. Western blot analysis and activity assay demonstrated that glycogen synthase was inhibited in glycolytic muscle from McArdle mice. The level and activation of proteins involved in contraction-induced glucose transport (AMPK, GLUT4) and glycogen synthase inhibition were increased in quadriceps muscle of McArdle mice. In addition, pCaMKII in quadriceps was reduced, suggesting lower insulin-induced glucose uptake, which could lead to lower glycogen accumulation. In comparison, tibialis anterior, extensor digitorum longus, and soleus had massive glycogen accumulation, but few, if any, changes or adaptations in glucose metabolism compared with wild-type mice. The findings suggest plasticity in glycogen metabolism in the McArdle mouse that is related to myosin heavy chain type IIB content in muscles. In patients, the level of GLUT4 was vastly increased, as were hexokinase II and phosphofructokinase, and glycogen synthase was more inhibited, suggesting that patients adapt by increasing capture of glucose for direct metabolism, thereby significantly reducing glycogen buildup compared with the mouse model. Hence, the McArdle mouse may be a useful tool for further comparative studies of disease mechanism caused by myophosphorylase deficiency and basic studies of metabolic adaptation in muscle.
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Affiliation(s)
- Thomas O Krag
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark;
| | - Tomàs Pinós
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Mitochondrial Pathology and Neuromuscular Disorders Laboratory, Vall d'Hebron Research Institute, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Tue L Nielsen
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jordi Duran
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Barcelona, Spain
| | - Mar García-Rocha
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain; and
| | - Antoni L Andreu
- Mitochondrial Pathology and Neuromuscular Disorders Laboratory, Vall d'Hebron Research Institute, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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Hargett SR, Walker NN, Keller SR. Rab GAPs AS160 and Tbc1d1 play nonredundant roles in the regulation of glucose and energy homeostasis in mice. Am J Physiol Endocrinol Metab 2016; 310:E276-88. [PMID: 26625902 PMCID: PMC4888528 DOI: 10.1152/ajpendo.00342.2015] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/29/2015] [Indexed: 11/22/2022]
Abstract
The related Rab GTPase-activating proteins (Rab GAPs) AS160 and Tbc1d1 regulate the trafficking of the glucose transporter GLUT4 that controls glucose uptake in muscle and fat cells and glucose homeostasis. AS160- and Tbc1d1-deficient mice exhibit different adipocyte- and skeletal muscle-specific defects in glucose uptake, GLUT4 expression and trafficking, and glucose homeostasis. A recent study analyzed male mice with simultaneous deletion of AS160 and Tbc1d1 (AS160(-/-)/Tbc1d1(-/-) mice). Herein, we describe abnormalities in male and female AS160(-/-)/Tbc1d1(-/-) mice on another strain background. We confirm the earlier observation that GLUT4 expression and glucose uptake defects of single-knockout mice join in AS160(-/-)/Tbc1d1(-/-) mice to affect all skeletal muscle and adipose tissues. In large mixed fiber-type skeletal muscles, changes in relative basal GLUT4 plasma membrane association in AS160(-/-) and Tbc1d1(-/-) mice also combine in AS160(-/-)/Tbc1d1(-/-) mice. However, we found different glucose uptake abnormalities in isolated skeletal muscles and adipocytes than reported previously, resulting in different interpretations of how AS160 and Tbc1d1 regulate GLUT4 translocation to the cell surface. In support of a larger role for AS160 in glucose homeostasis, in contrast with the previous study, we find similarly impaired glucose and insulin tolerance in AS160(-/-)/Tbc1d1(-/-) and AS160(-/-) mice. However, in vivo glucose uptake abnormalities in AS160(-/-)/Tbc1d1(-/-) skeletal muscles differ from those observed previously in AS160(-/-) mice, indicating additional defects due to Tbc1d1 deletion. Similar to AS160- and Tbc1d1-deficient mice, AS160(-/-)/Tbc1d1(-/-) mice show sex-specific abnormalities in glucose and energy homeostasis. In conclusion, our study supports nonredundant functions for AS160 and Tbc1d1.
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Affiliation(s)
- Stefan R Hargett
- Department of Medicine-Division of Endocrinology, University of Virginia, Charlottesville Virginia
| | - Natalie N Walker
- Department of Medicine-Division of Endocrinology, University of Virginia, Charlottesville Virginia
| | - Susanna R Keller
- Department of Medicine-Division of Endocrinology, University of Virginia, Charlottesville Virginia
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64
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Regulation of Carbohydrate Metabolism, Lipid Metabolism, and Protein Metabolism by AMPK. EXPERIENTIA SUPPLEMENTUM (2012) 2016; 107:23-43. [PMID: 27812975 DOI: 10.1007/978-3-319-43589-3_2] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This chapter summarizes AMPK function in the regulation of substrate and energy metabolism with the main emphasis on carbohydrate and lipid metabolism, protein turnover, mitochondrial biogenesis, and whole-body energy homeostasis. AMPK acts as whole-body energy sensor and integrates different signaling pathway to meet both cellular and body energy requirements while inhibiting energy-consuming processes but also activating energy-producing ones. AMPK mainly promotes glucose and fatty acid catabolism, whereas it prevents protein, glycogen, and fatty acid synthesis.
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65
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Liu K, Mei F, Wang Y, Xiao N, Yang L, Wang Y, Li J, Huang F, Kou J, Liu B, Qi LW. Quercetin oppositely regulates insulin-mediated glucose disposal in skeletal muscle under normal and inflammatory conditions: The dual roles of AMPK activation. Mol Nutr Food Res 2015; 60:551-65. [PMID: 26627467 DOI: 10.1002/mnfr.201500509] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 11/15/2015] [Accepted: 11/27/2015] [Indexed: 11/11/2022]
Abstract
SCOPE Quercetin is a dietary flavonoid whose role in the regulation of the activity of insulin remains controversial. Our study aimed to investigate how quercetin and its major metabolite quercetin-3-glucuronide (Q-3-G) regulate insulin-mediated glucose disposal in skeletal muscle under normal and inflammatory conditions. METHODS AND RESULTS Under normal conditions, quercetin impaired glucose and insulin tolerance and attenuated insulin-mediated phosphorylation of Akt substrate of 160 kDa (AS160) and TBC1D1 without affecting Akt activity in male Institute of Cancer Research (ICR) mice. However, under inflammatory conditions, quercetin exhibited an opposite effect in these animals. In C2C12 cells, quercetin also decreased insulin-stimulated AS160 and TBC1D1 phosphorylation and glucose uptake in the absence of an inflammatory insult, whereas it improved the action of insulin under inflammatory conditions. Knockdown of adenosine 5'-monophosphate-activated protein kinase α (AMPKα) blocked the differential effects of quercetin under both conditions. Unlike quercetin, Q-3-G had no influence on insulin-induced phosphorylation of AS160 and TBC1D1 and glucose uptake in C2C12 myotubes under normal conditions. Q-3-G displayed a similar regulation with quercetin in glucose disposal under inflammatory conditions. CONCLUSION Quercetin suppressed insulin-mediated glucose disposal in skeletal muscle tissue/cells under normal conditions while it ameliorated impaired glucose uptake under inflammatory conditions with activation of AMPK. In contrast, Q-3-G ameliorated insulin resistance in skeletal cells under inflammatory conditions without affecting glucose disposal under normal conditions.
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Affiliation(s)
- Kang Liu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, China
| | - Fan Mei
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, China
| | - Yapu Wang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, China
| | - Na Xiao
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Lele Yang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Yilei Wang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, China
| | - Jia Li
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Fang Huang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, China
| | - Junping Kou
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, China
| | - Baolin Liu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, China
| | - Lian-Wen Qi
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
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66
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Liang Y, Yuan W, Zhu W, Zhu J, Lin Q, Zou X, Deng C, Fu Y, Zheng X, Yang M, Wu S, Yu X, Shan Z. Macrophage migration inhibitory factor promotes expression of GLUT4 glucose transporter through MEF2 and Zac1 in cardiomyocytes. Metabolism 2015; 64:1682-93. [PMID: 26455966 DOI: 10.1016/j.metabol.2015.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 08/20/2015] [Accepted: 09/08/2015] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Evidence shows that both macrophage migration inhibitory factor (MIF) and GLUT4 glucose transporter are involved in diabetic cardiomyopathy (DCM), but it remains largely unknown whether and how MIF regulates GLUT4 expression in cardiomyocytes. The present study aims to investigate the mechanism underlying the modulation of GLUT4 by MIF in cardiomyocytes. MATERIAL AND METHODS Activations of AKT and AMPK signaling, and expressions of MIF, GLUT4 and the candidate GLUT4 regulation associated transcription factors in the diabetic mouse myocardium were determined. The screened transcription factors mediating MIF-promoted GLUT4 expression were verified by RNA interference (RNAi) and electrophoretic mobility shift assay (EMSA), respectively. RESULTS MIF was increased, but GLUT4 was decreased in the diabetic mouse myocardium. MIF could enhance glucose uptake and up-regulate GLUT4 expression in NMVCs. Expressions of transcription factor MEF2A, -2C, -2D and Zac1 were significantly up-regulated in MIF-treated neonatal mouse ventricular cardiomyocytes (NMVCs), and markedly reduced in the diabetic myocardium. Knockdown of MEF2A, -2C, -2D and Zac1 could significantly inhibit glucose uptake and GLUT4 expression in cardiomyocytes. Moreover, EMSA results revealed that transcriptional activities of MEF2 and Zac1 were significantly increased in MIF-treated NMVCs. AMPK signaling was activated in MIF-stimulated NMVCs, and AMPK activator AICAR could enhance MEF2A, -2C, -2D, Zac1 and GLUT4 expression. Additionally, MIF effects were inhibited by an AMPK inhibitor compound C and siRNA targeting MIF receptor CD74, suggesting the involvement of CD74-dependent AMPK activation. CONCLUSIONS Transcription factor MEF2 and Zac1 mediate MIF-induced GLUT4 expression through CD74-dependent AMPK activation in cardiomyocytes.
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Affiliation(s)
- Yeyou Liang
- Southern Medical University, 1838 Guangzhou Avenue North, Guangzhou, China.
| | - Weiwei Yuan
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Wensi Zhu
- Southern Medical University, 1838 Guangzhou Avenue North, Guangzhou, China.
| | - Jiening Zhu
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Qiuxiong Lin
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Xiao Zou
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Chunyu Deng
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Yongheng Fu
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Xilong Zheng
- The Libin Cardiovascular Institute of AB, Department of Biochemistry & Molecular Biology, Cumming School of Medicine, The University of Calgary, Calgary, Canada.
| | - Min Yang
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Shulin Wu
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Xiyong Yu
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Zhixin Shan
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
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67
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Kosfeld A, Kreuzer M, Daniel C, Brand F, Schäfer AK, Chadt A, Weiss AC, Riehmer V, Jeanpierre C, Klintschar M, Bräsen JH, Amann K, Pape L, Kispert A, Al-Hasani H, Haffner D, Weber RG. Whole-exome sequencing identifies mutations of TBC1D1 encoding a Rab-GTPase-activating protein in patients with congenital anomalies of the kidneys and urinary tract (CAKUT). Hum Genet 2015; 135:69-87. [PMID: 26572137 DOI: 10.1007/s00439-015-1610-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/04/2015] [Indexed: 01/06/2023]
Abstract
Congenital anomalies of the kidneys and urinary tract (CAKUT) are genetically highly heterogeneous leaving most cases unclear after mutational analysis of the around 30 causative genes known so far. Assuming that phenotypes frequently showing dominant inheritance, such as CAKUT, can be caused by de novo mutations, de novo analysis of whole-exome sequencing data was done on two patient-parent-trios to identify novel CAKUT genes. In one case, we detected a heterozygous de novo frameshift variant in TBC1D1 encoding a Rab-GTPase-activating protein regulating glucose transporter GLUT4 translocation. Sequence analysis of 100 further CAKUT cases yielded three novel or rare inherited heterozygous TBC1D1 missense variants predicted to be pathogenic. TBC1D1 mutations affected Ser237-phosphorylation or protein stability and thereby act as hypomorphs. Tbc1d1 showed widespread expression in the developing murine urogenital system. A mild CAKUT spectrum phenotype, including anomalies observed in patients carrying TBC1D1 mutations, was found in kidneys of some Tbc1d1 (-/-) mice. Significantly reduced Glut4 levels were detected in kidneys of Tbc1d1 (-/-) mice and the dysplastic kidney of a TBC1D1 mutation carrier versus controls. TBC1D1 and SLC2A4 encoding GLUT4 were highly expressed in human fetal kidney. The patient with the truncating TBC1D1 mutation showed evidence for insulin resistance. These data demonstrate heterozygous deactivating TBC1D1 mutations in CAKUT patients with a similar renal and ureteral phenotype, and provide evidence that TBC1D1 mutations may contribute to CAKUT pathogenesis, possibly via a role in glucose homeostasis.
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Affiliation(s)
- Anne Kosfeld
- Department of Human Genetics, OE 6300, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Martin Kreuzer
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Christoph Daniel
- Department of Nephropathology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Frank Brand
- Department of Human Genetics, OE 6300, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | | | - Alexandra Chadt
- German Diabetes Center, Leibniz Center for Diabetes Research at the Heinrich-Heine-University, Düsseldorf, Germany.,German Center for Diabetes Research (DZD), Düsseldorf, Germany
| | - Anna-Carina Weiss
- Institute of Molecular Biology, Hannover Medical School, Hannover, Germany
| | - Vera Riehmer
- Department of Human Genetics, OE 6300, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Cécile Jeanpierre
- Institut National de la Santé et de la Recherche Médicale UMR1163, Hôpital Necker-Enfants Malades, 75015, Paris, France.,Institut Imagine, Université Paris Descartes - Sorbonne Paris Cité, 75015, Paris, France
| | - Michael Klintschar
- Department of Legal Medicine, Hannover Medical School, Hannover, Germany
| | | | - Kerstin Amann
- Department of Nephropathology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Lars Pape
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Andreas Kispert
- Institute of Molecular Biology, Hannover Medical School, Hannover, Germany
| | - Hadi Al-Hasani
- German Diabetes Center, Leibniz Center for Diabetes Research at the Heinrich-Heine-University, Düsseldorf, Germany.,German Center for Diabetes Research (DZD), Düsseldorf, Germany
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Ruthild G Weber
- Department of Human Genetics, OE 6300, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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68
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Schaffer BE, Levin RS, Hertz NT, Maures TJ, Schoof ML, Hollstein PE, Benayoun BA, Banko MR, Shaw RJ, Shokat KM, Brunet A. Identification of AMPK Phosphorylation Sites Reveals a Network of Proteins Involved in Cell Invasion and Facilitates Large-Scale Substrate Prediction. Cell Metab 2015; 22:907-21. [PMID: 26456332 PMCID: PMC4635044 DOI: 10.1016/j.cmet.2015.09.009] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 07/28/2015] [Accepted: 09/08/2015] [Indexed: 12/22/2022]
Abstract
AMP-activated protein kinase (AMPK) is a central energy gauge that regulates metabolism and has been increasingly involved in non-metabolic processes and diseases. However, AMPK's direct substrates in non-metabolic contexts are largely unknown. To better understand the AMPK network, we use a chemical genetics screen coupled to a peptide capture approach in whole cells, resulting in identification of direct AMPK phosphorylation sites. Interestingly, the high-confidence AMPK substrates contain many proteins involved in cell motility, adhesion, and invasion. AMPK phosphorylation of the RHOA guanine nucleotide exchange factor NET1A inhibits extracellular matrix degradation, an early step in cell invasion. The identification of direct AMPK phosphorylation sites also facilitates large-scale prediction of AMPK substrates. We provide an AMPK motif matrix and a pipeline to predict additional AMPK substrates from quantitative phosphoproteomics datasets. As AMPK is emerging as a critical node in aging and pathological processes, our study identifies potential targets for therapeutic strategies.
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Affiliation(s)
- Bethany E Schaffer
- Cancer Biology Program, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Rebecca S Levin
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, CA 94158, USA
| | - Nicholas T Hertz
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, CA 94158, USA
| | - Travis J Maures
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Michael L Schoof
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Pablo E Hollstein
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | | | - Max R Banko
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Reuben J Shaw
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Kevan M Shokat
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, CA 94158, USA
| | - Anne Brunet
- Cancer Biology Program, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA; Glenn Laboratories for the Biology of Aging, Stanford, CA 94305, USA.
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Ha J, Guan KL, Kim J. AMPK and autophagy in glucose/glycogen metabolism. Mol Aspects Med 2015; 46:46-62. [PMID: 26297963 DOI: 10.1016/j.mam.2015.08.002] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/04/2015] [Indexed: 12/14/2022]
Abstract
Glucose/glycogen metabolism is a primary metabolic pathway acting on a variety of cellular needs, such as proliferation, growth, and survival against stresses. The multiple regulatory mechanisms underlying a specific metabolic fate have been documented and explained the molecular basis of various pathophysiological conditions, including metabolic disorders and cancers. AMP-activated protein kinase (AMPK) has been appreciated for many years as a central metabolic regulator to inhibit energy-consuming pathways as well as to activate the compensating energy-producing programs. In fact, glucose starvation is a potent physiological AMPK activating condition, in which AMPK triggers various subsequent metabolic events depending on cells or tissues. Of note, the recent studies show bidirectional interplay between AMPK and glycogen. A growing number of studies have proposed additional level of metabolic regulation by a lysosome-dependent catabolic program, autophagy. Autophagy is a critical degradative pathway not only for maintenance of cellular homeostasis to remove potentially dangerous constituents, such as protein aggregates and dysfunctional subcellular organelles, but also for adaptive responses to metabolic stress, such as nutrient starvation. Importantly, many lines of evidence indicate that autophagy is closely connected with nutrient signaling modules, including AMPK, to fine-tune the metabolic pathways in response to many different cellular cues. In this review, we introduce the studies demonstrating the role of AMPK and autophagy in glucose/glycogen metabolism. Also, we describe the recent advances on their contributions to the metabolic disorders.
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Affiliation(s)
- Joohun Ha
- Department of Biochemistry and Molecular Biology, Medical Research Center and Biomedical Science Institute, School of Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Kun-Liang Guan
- Department of Pharmacology, Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Joungmok Kim
- Department of Oral Biochemistry and Molecular Biology, Research Center for Tooth and Periodontal Tissue Regeneration, School of Dentistry, Kyung Hee University, Seoul, Republic of Korea.
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70
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Hargett SR, Walker NN, Hussain SS, Hoehn KL, Keller SR. Deletion of the Rab GAP Tbc1d1 modifies glucose, lipid, and energy homeostasis in mice. Am J Physiol Endocrinol Metab 2015; 309:E233-45. [PMID: 26015432 PMCID: PMC4525116 DOI: 10.1152/ajpendo.00007.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 05/24/2015] [Indexed: 11/22/2022]
Abstract
Tbc1d1 is a Rab GTPase-activating protein (GAP) implicated in regulating intracellular retention and cell surface localization of the glucose transporter GLUT4 and thus glucose uptake in a phosphorylation-dependent manner. Tbc1d1 is most abundant in skeletal muscle but is expressed at varying levels among different skeletal muscles. Previous studies with male Tbc1d1-deficient (Tbc1d1(-/-)) mice on standard and high-fat diets established a role for Tbc1d1 in glucose, lipid, and energy homeostasis. Here we describe similar, but also additional abnormalities in male and female Tbc1d1(-/-) mice. We corroborate that Tbc1d1 loss leads to skeletal muscle-specific and skeletal muscle type-dependent abnormalities in GLUT4 expression and glucose uptake in female and male mice. Using subcellular fractionation, we show that Tbc1d1 controls basal intracellular GLUT4 retention in large skeletal muscles. However, cell surface labeling of extensor digitorum longus muscle indicates that Tbc1d1 does not regulate basal GLUT4 cell surface exposure as previously suggested. Consistent with earlier observations, female and male Tbc1d1(-/-) mice demonstrate increased energy expenditure and skeletal muscle fatty acid oxidation. Interestingly, we observe sex-dependent differences in in vivo phenotypes. Female, but not male, Tbc1d1(-/-) mice have decreased body weight and impaired glucose and insulin tolerance, but only male Tbc1d1(-/-) mice show increased lipid clearance after oil gavage. We surmise that similar changes at the tissue level cause differences in whole-body metabolism between male and female Tbc1d1(-/-) mice and between male Tbc1d1(-/-) mice in different studies due to variations in body composition and nutrient handling.
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Affiliation(s)
- Stefan R Hargett
- Department of Medicine, Division of Endocrinology, University of Virginia, Charlottesville Virginia
| | - Natalie N Walker
- Department of Medicine, Division of Endocrinology, University of Virginia, Charlottesville Virginia
| | - Syed S Hussain
- Department of Medicine, Division of Endocrinology, University of Virginia, Charlottesville Virginia
| | - Kyle L Hoehn
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia
| | - Susanna R Keller
- Department of Medicine, Division of Endocrinology, University of Virginia, Charlottesville Virginia;
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71
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Stöckli J, Meoli CC, Hoffman NJ, Fazakerley DJ, Pant H, Cleasby ME, Ma X, Kleinert M, Brandon AE, Lopez JA, Cooney GJ, James DE. The RabGAP TBC1D1 plays a central role in exercise-regulated glucose metabolism in skeletal muscle. Diabetes 2015; 64:1914-22. [PMID: 25576050 DOI: 10.2337/db13-1489] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 12/24/2014] [Indexed: 11/13/2022]
Abstract
Insulin and exercise stimulate glucose uptake into skeletal muscle via different pathways. Both stimuli converge on the translocation of the glucose transporter GLUT4 from intracellular vesicles to the cell surface. Two Rab guanosine triphosphatases-activating proteins (GAPs) have been implicated in this process: AS160 for insulin stimulation and its homolog, TBC1D1, are suggested to regulate exercise-mediated glucose uptake into muscle. TBC1D1 has also been implicated in obesity in humans and mice. We investigated the role of TBC1D1 in glucose metabolism by generating TBC1D1(-/-) mice and analyzing body weight, insulin action, and exercise. TBC1D1(-/-) mice showed normal glucose and insulin tolerance, with no difference in body weight compared with wild-type littermates. GLUT4 protein levels were reduced by ∼40% in white TBC1D1(-/-) muscle, and TBC1D1(-/-) mice showed impaired exercise endurance together with impaired exercise-mediated 2-deoxyglucose uptake into white but not red muscles. These findings indicate that the RabGAP TBC1D1 plays a key role in regulating GLUT4 protein levels and in exercise-mediated glucose uptake in nonoxidative muscle fibers.
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Affiliation(s)
- Jacqueline Stöckli
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia Garvan Institute of Medical Research, Sydney, New South Wales, Australia St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Christopher C Meoli
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Nolan J Hoffman
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Daniel J Fazakerley
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Himani Pant
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Mark E Cleasby
- The Royal Veterinary College, University of London, London, U.K
| | - Xiuquan Ma
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Maximilian Kleinert
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia Molecular Physiology Group, Department of Nutrition, Exercise and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Amanda E Brandon
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Jamie A Lopez
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Gregory J Cooney
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - David E James
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia Garvan Institute of Medical Research, Sydney, New South Wales, Australia School of Medicine, University of Sydney, Sydney, New South Wales, Australia
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72
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Kjøbsted R, Treebak JT, Fentz J, Lantier L, Viollet B, Birk JB, Schjerling P, Björnholm M, Zierath JR, Wojtaszewski JFP. Prior AICAR stimulation increases insulin sensitivity in mouse skeletal muscle in an AMPK-dependent manner. Diabetes 2015; 64:2042-55. [PMID: 25552597 DOI: 10.2337/db14-1402] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 12/20/2014] [Indexed: 11/13/2022]
Abstract
An acute bout of exercise increases glucose uptake in skeletal muscle by an insulin-independent mechanism. In the period after exercise, insulin sensitivity to increased glucose uptake is enhanced. The molecular mechanisms underpinning this phenomenon are poorly understood but appear to involve an increased cell surface abundance of GLUT4. While increased proximal insulin signaling does not seem to mediate this effect, elevated phosphorylation of TBC1D4, a downstream target of both insulin (Akt) and exercise (AMPK) signaling, appears to play a role. The main purpose of this study was to determine whether AMPK activation increases skeletal muscle insulin sensitivity. We found that prior AICAR stimulation of wild-type mouse muscle increases insulin sensitivity to stimulate glucose uptake. However, this was not observed in mice with reduced or ablated AMPK activity in skeletal muscle. Furthermore, prior AICAR stimulation enhanced insulin-stimulated phosphorylation of TBC1D4 at Thr(649) and Ser(711) in wild-type muscle only. These phosphorylation events were positively correlated with glucose uptake. Our results provide evidence to support that AMPK activation is sufficient to increase skeletal muscle insulin sensitivity. Moreover, TBC1D4 phosphorylation may facilitate the effect of prior AMPK activation to enhance glucose uptake in response to insulin.
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Affiliation(s)
- Rasmus Kjøbsted
- Section of Molecular Physiology, August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark The Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Jonas T Treebak
- Section of Molecular Physiology, August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark The Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Joachim Fentz
- Section of Molecular Physiology, August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Louise Lantier
- INSERM, U1016, Institut Cochin, Paris, France CNRS, UMR8104, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Benoit Viollet
- INSERM, U1016, Institut Cochin, Paris, France CNRS, UMR8104, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jesper B Birk
- Section of Molecular Physiology, August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Peter Schjerling
- Institute of Sports Medicine, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marie Björnholm
- Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Juleen R Zierath
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, University of Copenhagen, Copenhagen, Denmark Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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73
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Jensen TE, Ross FA, Kleinert M, Sylow L, Knudsen JR, Hardie DG, Richter EA. PT-1 selectively activates AMPK-γ1 complexes in mouse skeletal muscle, but activates all three γ subunit complexes in cultured human cells by inhibiting the respiratory chain. Biochem J 2015; 467:461-72. [PMID: 25695398 PMCID: PMC5689378 DOI: 10.1042/bj20141142] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
AMP-activated protein kinase (AMPK) occurs as heterotrimeric complexes in which a catalytic subunit (α1/α2) is bound to one of two β subunits (β1/β2) and one of three γ subunits (γ1/γ2/γ3). The ability to selectively activate specific isoforms would be a useful research tool and a promising strategy to combat diseases such as cancer and Type 2 diabetes. We report that the AMPK activator PT-1 selectively increased the activity of γ1- but not γ3-containing complexes in incubated mouse muscle. PT-1 increased the AMPK-dependent phosphorylation of the autophagy-regulating kinase ULK1 (unc-51-like autophagy-activating kinase 1) on Ser555, but not proposed AMPK-γ3 substrates such as Ser231 on TBC1 (tre-2/USP6, BUB2, cdc16) domain family, member 1 (TBC1D1) or Ser212 on acetyl-CoA carboxylase subunit 2 (ACC2), nor did it stimulate glucose transport. Surprisingly, however, in human embryonic kidney (HEK) 293 cells expressing human γ1, γ2 or γ3, PT-1 activated all three complexes equally. We were unable to reproduce previous findings suggesting that PT-1 activates AMPK by direct binding between the kinase and auto-inhibitory domains (AIDs) of the α subunit. We show instead that PT-1 activates AMPK indirectly by inhibiting the respiratory chain and increasing cellular AMP:ATP and/or ADP:ATP ratios. Consistent with this mechanism, PT-1 failed to activate AMPK in HEK293 cells expressing an AMP-insensitive R299G mutant of AMPK-γ1. We propose that the failure of PT-1 to activate γ3-containing complexes in muscle is not an intrinsic feature of such complexes, but is because PT-1 does not increase cellular AMP:ATP ratios in the specific subcellular compartment(s) in which γ3 complexes are located.
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Affiliation(s)
- Thomas E. Jensen
- Corresponding author: Thomas E. Jensen, Department of Nutrition, Exercise and Sports, Universitetsparken 13, 307, 2100 Copenhagen, Denmark, , (+45)-30593437
| | - Fiona A. Ross
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland, UK
| | - Maximilian Kleinert
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Universitetsparken 13, 2100 Copenhagen, Denmark
| | - Lykke Sylow
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Universitetsparken 13, 2100 Copenhagen, Denmark
| | - Jonas R. Knudsen
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Universitetsparken 13, 2100 Copenhagen, Denmark
| | - D. Grahame Hardie
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland, UK
| | - Erik A. Richter
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Universitetsparken 13, 2100 Copenhagen, Denmark
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74
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Quan C, Xie B, Wang HY, Chen S. PKB-Mediated Thr649 Phosphorylation of AS160/TBC1D4 Regulates the R-Wave Amplitude in the Heart. PLoS One 2015; 10:e0124491. [PMID: 25923736 PMCID: PMC4414484 DOI: 10.1371/journal.pone.0124491] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/04/2015] [Indexed: 11/18/2022] Open
Abstract
The Rab GTPase activating protein (RabGAP), AS160/TBC1D4, is an important substrate of protein kinase B (PKB), and regulates insulin-stimulated trafficking of glucose transporter 4. Besides, AS160/TBC1D4 has also been shown to regulate trafficking of many other membrane proteins including FA translocase/CD36 in cardiomyocytes. However, it is not clear whether it plays any role in regulating heart functions in vivo. Here, we found that PKB-mediated phosphorylation of Thr649 on AS160/TBC1D4 represented one of the major PAS-binding signals in the heart in response to insulin. Mutation of Thr649 to a non-phosphorylatable alanine increased the R-wave amplitude in the AS160Thr649Ala knockin mice. However, this knockin mutation did not affect the heart functions under both normal and infarct conditions. Interestingly, myocardial infarction induced the expression of a related RabGAP, TBC1D1, in the infarct zone as well as in the border zone. Together, these data show that the Thr649 phosphorylation of AS160/TBC1D4 plays an important role in the heart’s electrical conduction system through regulating the R-wave amplitude.
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Affiliation(s)
- Chao Quan
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, 210061, China
| | - Bingxian Xie
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, 210061, China
| | - Hong Yu Wang
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, 210061, China
- * E-mail: (HYW); ( (SC)
| | - Shuai Chen
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, 210061, China
- * E-mail: (HYW); ( (SC)
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75
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Chadt A, Immisch A, de Wendt C, Springer C, Zhou Z, Stermann T, Holman GD, Loffing-Cueni D, Loffing J, Joost HG, Al-Hasani H. “Deletion of both Rab-GTPase–activating proteins TBC1D1 and TBC1D4 in mice eliminates insulin- and AICAR-stimulated glucose transport [corrected]. Diabetes 2015; 64:746-59. [PMID: 25249576 DOI: 10.2337/db14-0368] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The Rab-GTPase–activating proteins TBC1D1 and TBC1D4 (AS160) were previously shown to regulate GLUT4 translocation in response to activation of AKT and AMP-dependent kinase [corrected]. However, knockout mice lacking either Tbc1d1 or Tbc1d4 displayed only partially impaired insulin-stimulated glucose uptake in fat and muscle tissue. The aim of this study was to determine the impact of the combined inactivation of Tbc1d1 and Tbc1d4 on glucose metabolism in double-deficient (D1/4KO) mice. D1/4KO mice displayed normal fasting glucose concentrations but had reduced tolerance to intraperitoneally administered glucose, insulin, and AICAR. D1/4KO mice showed reduced respiratory quotient, indicating increased use of lipids as fuel. These mice also consistently showed elevated fatty acid oxidation in isolated skeletal muscle, whereas insulin-stimulated glucose uptake in muscle and adipose cells was almost completely abolished. In skeletal muscle and white adipose tissue, the abundance of GLUT4 protein, but not GLUT4 mRNA, was substantially reduced. Cell surface labeling of GLUTs indicated that RabGAP deficiency impairs retention of GLUT4 in intracellular vesicles in the basal state. Our results show that TBC1D1 and TBC1D4 together play essential roles in insulin-stimulated glucose uptake and substrate preference in skeletal muscle and adipose cells.
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Affiliation(s)
- Alexandra Chadt
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich-Heine-University, Düsseldorf, Germany German Center for Diabetes Research (DZD), Düsseldorf, Germany
| | - Anja Immisch
- German Institute for Human Nutrition, Potsdam, Germany
| | - Christian de Wendt
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich-Heine-University, Düsseldorf, Germany
| | - Christian Springer
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich-Heine-University, Düsseldorf, Germany
| | - Zhou Zhou
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich-Heine-University, Düsseldorf, Germany
| | - Torben Stermann
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich-Heine-University, Düsseldorf, Germany
| | - Geoffrey D Holman
- Department of Biology and Biochemistry, University of Bath, Bath, U.K
| | | | | | - Hans-Georg Joost
- German Center for Diabetes Research (DZD), Düsseldorf, Germany German Institute for Human Nutrition, Potsdam, Germany
| | - Hadi Al-Hasani
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich-Heine-University, Düsseldorf, Germany German Center for Diabetes Research (DZD), Düsseldorf, Germany
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76
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Cartee GD. Roles of TBC1D1 and TBC1D4 in insulin- and exercise-stimulated glucose transport of skeletal muscle. Diabetologia 2015; 58:19-30. [PMID: 25280670 PMCID: PMC4258142 DOI: 10.1007/s00125-014-3395-5] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/07/2014] [Indexed: 10/24/2022]
Abstract
This review focuses on two paralogue Rab GTPase activating proteins known as TBC1D1 Tre-2/BUB2/cdc 1 domain family (TBC1D) 1 and TBC1D4 (also called Akt Substrate of 160 kDa, AS160) and their roles in controlling skeletal muscle glucose transport in response to the independent and combined effects of insulin and exercise. Convincing evidence implicates Akt2-dependent TBC1D4 phosphorylation on T642 as a key part of the mechanism for insulin-stimulated glucose uptake by skeletal muscle. TBC1D1 phosphorylation on several insulin-responsive sites (including T596, a site corresponding to T642 in TBC1D4) does not appear to be essential for in vivo insulin-stimulated glucose uptake by skeletal muscle. In vivo exercise or ex vivo contraction of muscle result in greater TBC1D1 phosphorylation on S237 that is likely to be secondary to increased AMP-activated protein kinase activity and potentially important for contraction-stimulated glucose uptake. Several studies that evaluated both normal and insulin-resistant skeletal muscle stimulated with a physiological insulin concentration after a single exercise session found that greater post-exercise insulin-stimulated glucose uptake was accompanied by greater TBC1D4 phosphorylation on several sites. In contrast, enhanced post-exercise insulin sensitivity was not accompanied by greater insulin-stimulated TBC1D1 phosphorylation. The mechanism for greater TBC1D4 phosphorylation in insulin-stimulated muscles after acute exercise is uncertain, and a causal link between enhanced TBC1D4 phosphorylation and increased post-exercise insulin sensitivity has yet to be established. In summary, TBC1D1 and TBC1D4 have important, but distinct roles in regulating muscle glucose transport in response to insulin and exercise.
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Affiliation(s)
- Gregory D Cartee
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, 401 Washtenaw Avenue, Ann Arbor, MI, 48109-2214, USA,
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77
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Grahame Hardie D. AMP-activated protein kinase: a key regulator of energy balance with many roles in human disease. J Intern Med 2014; 276:543-59. [PMID: 24824502 PMCID: PMC5705060 DOI: 10.1111/joim.12268] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The AMP-activated protein kinase (AMPK) is a sensor of cellular energy status that regulates cellular and whole-body energy balance. A recently reported crystal structure has illuminated the complex regulatory mechanisms by which AMP and ADP cause activation of AMPK, involving phosphorylation by the upstream kinase LKB1. Once activated by falling cellular energy status, AMPK activates catabolic pathways that generate ATP whilst inhibiting anabolic pathways and other cellular processes that consume ATP. A role of AMPK is implicated in many human diseases. Mutations in the γ2 subunit cause heart disease due to excessive glycogen storage in cardiac myocytes, leading to ventricular pre-excitation. AMPK-activating drugs reverse many of the metabolic defects associated with insulin resistance, and recent findings suggest that the insulin-sensitizing effects of the widely used antidiabetic drug metformin are mediated by AMPK. The upstream kinase LKB1 is a tumour suppressor, and AMPK may exert many of its antitumour effects. AMPK activation promotes the oxidative metabolism typical of quiescent cells, rather than the aerobic glycolysis observed in tumour cells and cells involved in inflammation, explaining in part why AMPK activators have both antitumour and anti-inflammatory effects. Salicylate (the major in vivo metabolite of aspirin) activates AMPK, and this could be responsible for at least some of the anticancer and anti-inflammatory effects of aspirin. In addition to metformin and salicylates, novel drugs that modulate AMPK are likely to enter clinical trials soon. Finally, AMPK may be involved in viral infection: downregulation of AMPK during hepatitis C virus infection appears to be essential for efficient viral replication.
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Affiliation(s)
- D Grahame Hardie
- Division of Cell Signalling and Immunology, College of Life Sciences, University of Dundee, Scotland, UK
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78
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Krishan S, Richardson DR, Sahni S. Adenosine Monophosphate–Activated Kinase and Its Key Role in Catabolism: Structure, Regulation, Biological Activity, and Pharmacological Activation. Mol Pharmacol 2014; 87:363-77. [DOI: 10.1124/mol.114.095810] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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79
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Cheng KKY, Zhu W, Chen B, Wang Y, Wu D, Sweeney G, Wang B, Lam KSL, Xu A. The adaptor protein APPL2 inhibits insulin-stimulated glucose uptake by interacting with TBC1D1 in skeletal muscle. Diabetes 2014; 63:3748-58. [PMID: 24879834 DOI: 10.2337/db14-0337] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Insulin stimulates glucose uptake by promoting the trafficking of GLUT4 to the plasma membrane in muscle cells, and impairment of this insulin action contributes to hyperglycemia in type 2 diabetes. The adaptor protein APPL1 potentiates insulin-stimulated Akt activation and downstream actions. However, the physiological functions of APPL2, a close homolog of APPL1, in regulating glucose metabolism remain elusive. We show that insulin-evoked plasma membrane recruitment of GLUT4 and glucose uptake are impaired by APPL2 overexpression but enhanced by APPL2 knockdown. Likewise, conditional deletion of APPL2 in skeletal muscles enhances insulin sensitivity, leading to an improvement in glucose tolerance. We identified the Rab-GTPase-activating protein TBC1D1 as an interacting partner of APPL2. Insulin stimulates TBC1D1 phosphorylation on serine 235, leading to enhanced interaction with the BAR domain of APPL2, which in turn suppresses insulin-evoked TBC1D1 phosphorylation on threonine 596 in cultured myotubes and skeletal muscle. Substitution of serine 235 with alanine diminishes APPL2-mediated inhibition on insulin-dependent TBC1D1 phosphorylation on threonine 596 and the suppressive effects of TBC1D1 on insulin-induced glucose uptake and GLUT4 translocation to the plasma membrane in cultured myotubes. Therefore, the APPL2-TBC1D1 interaction is a key step to fine tune insulin-stimulated glucose uptake by regulating the membrane recruitment of GLUT4 in skeletal muscle.
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Affiliation(s)
- Kenneth K Y Cheng
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong Department of Medicine, The University of Hong Kong, Hong Kong
| | - Weidong Zhu
- Department of Medicine, The University of Hong Kong, Hong Kong
| | - Bin Chen
- Department of Medicine, The University of Hong Kong, Hong Kong
| | - Yu Wang
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong Department of Pharmacology & Pharmacy, The University of Hong Kong, Hong Kong
| | - Donghai Wu
- The Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Gary Sweeney
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Baile Wang
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong Department of Medicine, The University of Hong Kong, Hong Kong
| | - Karen S L Lam
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong Department of Medicine, The University of Hong Kong, Hong Kong
| | - Aimin Xu
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong Department of Medicine, The University of Hong Kong, Hong Kong Department of Pharmacology & Pharmacy, The University of Hong Kong, Hong Kong
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80
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Chen Q, Quan C, Xie B, Chen L, Zhou S, Toth R, Campbell DG, Lu S, Shirakawa R, Horiuchi H, Li C, Yang Z, MacKintosh C, Wang HY, Chen S. GARNL1, a major RalGAP α subunit in skeletal muscle, regulates insulin-stimulated RalA activation and GLUT4 trafficking via interaction with 14-3-3 proteins. Cell Signal 2014; 26:1636-48. [DOI: 10.1016/j.cellsig.2014.04.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 04/11/2014] [Indexed: 11/16/2022]
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81
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Tinti M, Dissanayake K, Synowsky S, Albergante L, MacKintosh C. Identification of 2R-ohnologue gene families displaying the same mutation-load skew in multiple cancers. Open Biol 2014; 4:140029. [PMID: 24806839 PMCID: PMC4042849 DOI: 10.1098/rsob.140029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 04/09/2014] [Indexed: 12/12/2022] Open
Abstract
The complexity of signalling pathways was boosted at the origin of the vertebrates, when two rounds of whole genome duplication (2R-WGD) occurred. Those genes and proteins that have survived from the 2R-WGD-termed 2R-ohnologues-belong to families of two to four members, and are enriched in signalling components relevant to cancer. Here, we find that while only approximately 30% of human transcript-coding genes are 2R-ohnologues, they carry 42-60% of the gene mutations in 30 different cancer types. Across a subset of cancer datasets, including melanoma, breast, lung adenocarcinoma, liver and medulloblastoma, we identified 673 2R-ohnologue families in which one gene carries mutations at multiple positions, while sister genes in the same family are relatively mutation free. Strikingly, in 315 of the 322 2R-ohnologue families displaying such a skew in multiple cancers, the same gene carries the heaviest mutation load in each cancer, and usually the second-ranked gene is also the same in each cancer. Our findings inspire the hypothesis that in certain cancers, heterogeneous combinations of genetic changes impair parts of the 2R-WGD signalling networks and force information flow through a limited set of oncogenic pathways in which specific non-mutated 2R-ohnologues serve as effectors. The non-mutated 2R-ohnologues are therefore potential therapeutic targets. These include proteins linked to growth factor signalling, neurotransmission and ion channels.
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Affiliation(s)
- Michele Tinti
- Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Kumara Dissanayake
- Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Silvia Synowsky
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee DD1 5EH, UK
| | - Luca Albergante
- Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
- Division of Computational Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Carol MacKintosh
- Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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82
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Investigation of LKB1 Ser431 phosphorylation and Cys433 farnesylation using mouse knockin analysis reveals an unexpected role of prenylation in regulating AMPK activity. Biochem J 2014; 458:41-56. [PMID: 24295069 PMCID: PMC3898322 DOI: 10.1042/bj20131324] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The LKB1 tumour suppressor protein kinase functions to activate two isoforms of AMPK (AMP-activated protein kinase) and 12 members of the AMPK-related family of protein kinases. The highly conserved C-terminal residues of LKB1 are phosphorylated (Ser431) by PKA (cAMP-dependent protein kinase) and RSK (ribosomal S6 kinase) and farnesylated (Cys433) within a CAAX motif. To better define the role that these post-translational modifications play, we created homozygous LKB1S431A/S431A and LKB1C433S/C433S knockin mice. These animals were viable, fertile and displayed no overt phenotypes. Employing a farnesylation-specific monoclonal antibody that we generated, we established by immunoprecipitation that the vast majority, if not all, of the endogenous LKB1 is prenylated. Levels of LKB1 localized at the membrane of the liver of LKB1C433S/C433S mice and their fibroblasts were reduced substantially compared with the wild-type mice, confirming that farnesylation plays a role in mediating membrane association. Although AMPK was activated normally in the LKB1S431A/S431A animals, we unexpectedly observed in all of the examined tissues and cells taken from LKB1C433S/C433S mice that the basal, as well as that induced by the AMP-mimetic AICAR (5-amino-4-imidazolecarboxamide riboside), AMPK activation, phenformin and muscle contraction were significantly blunted. This resulted in a reduced ability of AICAR to inhibit lipid synthesis in primary hepatocytes isolated from LKB1C433S/C433S mice. The activity of several of the AMPK-related kinases analysed [BRSK1 (BR serine/threonine kinase 1), BRSK2, NUAK1 (NUAK family, SNF1-like kinase 1), SIK3 (salt-inducible kinase 3) and MARK4 (MAP/microtubule affinity-regulating kinase 4)] was not affected in tissues derived from LKB1S431A/S431A or LKB1C433S/C433S mice. Our observations reveal for the first time that farnesylation of LKB1 is required for the activation of AMPK. Previous reports have indicated that a pool of AMPK is localized at the plasma membrane as a result of myristoylation of its regulatory AMPKβ subunit. This raises the possibility that LKB1 farnesylation and myristoylation of AMPKβ might promote the interaction and co-localization of these enzymes on a two-dimensional membrane surface and thereby promote efficient activation of AMPK.
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83
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Hoffman NJ, Penque BA, Habegger KM, Sealls W, Tackett L, Elmendorf JS. Chromium enhances insulin responsiveness via AMPK. J Nutr Biochem 2014; 25:565-72. [PMID: 24725432 DOI: 10.1016/j.jnutbio.2014.01.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 01/02/2014] [Accepted: 01/24/2014] [Indexed: 12/19/2022]
Abstract
Trivalent chromium (Cr(3+)) is known to improve glucose homeostasis. Cr(3+) has been shown to improve plasma membrane-based aspects of glucose transporter GLUT4 regulation and increase activity of the cellular energy sensor 5' AMP-activated protein kinase (AMPK). However, the mechanism(s) by which Cr(3+) improves insulin responsiveness and whether AMPK mediates this action is not known. In this study we tested if Cr(3+) protected against physiological hyperinsulinemia-induced plasma membrane cholesterol accumulation, cortical filamentous actin (F-actin) loss and insulin resistance in L6 skeletal muscle myotubes. In addition, we performed mechanistic studies to test our hypothesis that AMPK mediates the effects of Cr(3+) on GLUT4 and glucose transport regulation. Hyperinsulinemia-induced insulin-resistant L6 myotubes displayed excess membrane cholesterol and diminished cortical F-actin essential for effective glucose transport regulation. These membrane and cytoskeletal abnormalities were associated with defects in insulin-stimulated GLUT4 translocation and glucose transport. Supplementing the culture medium with pharmacologically relevant doses of Cr(3+) in the picolinate form (CrPic) protected against membrane cholesterol accumulation, F-actin loss, GLUT4 dysregulation and glucose transport dysfunction. Insulin signaling was neither impaired by hyperinsulinemic conditions nor enhanced by CrPic, whereas CrPic increased AMPK signaling. Mechanistically, siRNA-mediated depletion of AMPK abolished the protective effects of CrPic against GLUT4 and glucose transport dysregulation. Together these findings suggest that the micronutrient Cr(3+), via increasing AMPK activity, positively impacts skeletal muscle cell insulin sensitivity and glucose transport regulation.
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Affiliation(s)
- Nolan J Hoffman
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Brent A Penque
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Kirk M Habegger
- Department of Biochemistry and Molecular Biology, Center for Diabetes Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Department of Medicine - Endocrinology, Diabetes & Metabolism University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Whitney Sealls
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Lixuan Tackett
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Jeffrey S Elmendorf
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Department of Biochemistry and Molecular Biology, Center for Diabetes Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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84
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Treebak JT, Pehmøller C, Kristensen JM, Kjøbsted R, Birk JB, Schjerling P, Richter EA, Goodyear LJ, Wojtaszewski JFP. Acute exercise and physiological insulin induce distinct phosphorylation signatures on TBC1D1 and TBC1D4 proteins in human skeletal muscle. J Physiol 2013; 592:351-75. [PMID: 24247980 DOI: 10.1113/jphysiol.2013.266338] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We investigated the phosphorylation signatures of two Rab-GTPase activating proteins TBC1D1 and TBC1D4 in human skeletal muscle in response to physical exercise and physiological insulin levels induced by a carbohydrate rich meal using a paired experimental design. Eight healthy male volunteers exercised in the fasted or fed state and muscle biopsies were taken before and immediately after exercise. We identified TBC1D1/4 phospho-sites that (1) did not respond to exercise or postprandial increase in insulin (TBC1D4: S666), (2) responded to insulin only (TBC1D4: S318), (3) responded to exercise only (TBC1D1: S237, S660, S700; TBC1D4: S588, S751), and (4) responded to both insulin and exercise (TBC1D1: T596; TBC1D4: S341, T642, S704). In the insulin-stimulated leg, Akt phosphorylation of both T308 and S473 correlated significantly with multiple sites on both TBC1D1 (T596) and TBC1D4 (S318, S341, S704). Interestingly, in the exercised leg in the fasted state TBC1D1 phosphorylation (S237, T596) correlated significantly with the activity of the α2/β2/γ3 AMPK trimer, whereas TBC1D4 phosphorylation (S341, S704) correlated with the activity of the α2/β2/γ1 AMPK trimer. Our data show differential phosphorylation of TBC1D1 and TBC1D4 in response to physiological stimuli in human skeletal muscle and support the idea that Akt and AMPK are upstream kinases. TBC1D1 phosphorylation signatures were comparable between in vitro contracted mouse skeletal muscle and exercised human muscle, and we show that AMPK regulated phosphorylation of these sites in mouse muscle. Contraction and exercise elicited a different phosphorylation pattern of TBC1D4 in mouse compared with human muscle, and although different circumstances in our experimental setup may contribute to this difference, the observation exemplifies that transferring findings between species is problematic.
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Affiliation(s)
- Jonas T Treebak
- The August Krogh Centre, Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Universitetsparken 13 DK-2100, Copenhagen, Denmark.
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85
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Abstract
Glucose is an important fuel for contracting muscle, and normal glucose metabolism is vital for health. Glucose enters the muscle cell via facilitated diffusion through the GLUT4 glucose transporter which translocates from intracellular storage depots to the plasma membrane and T-tubules upon muscle contraction. Here we discuss the current understanding of how exercise-induced muscle glucose uptake is regulated. We briefly discuss the role of glucose supply and metabolism and concentrate on GLUT4 translocation and the molecular signaling that sets this in motion during muscle contractions. Contraction-induced molecular signaling is complex and involves a variety of signaling molecules including AMPK, Ca(2+), and NOS in the proximal part of the signaling cascade as well as GTPases, Rab, and SNARE proteins and cytoskeletal components in the distal part. While acute regulation of muscle glucose uptake relies on GLUT4 translocation, glucose uptake also depends on muscle GLUT4 expression which is increased following exercise. AMPK and CaMKII are key signaling kinases that appear to regulate GLUT4 expression via the HDAC4/5-MEF2 axis and MEF2-GEF interactions resulting in nuclear export of HDAC4/5 in turn leading to histone hyperacetylation on the GLUT4 promoter and increased GLUT4 transcription. Exercise training is the most potent stimulus to increase skeletal muscle GLUT4 expression, an effect that may partly contribute to improved insulin action and glucose disposal and enhanced muscle glycogen storage following exercise training in health and disease.
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Affiliation(s)
- Erik A Richter
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
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86
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Mendias CL, Lynch EB, Davis ME, Enselman ERS, Harning JA, DeWolf PD, Makki TA, Bedi A. Changes in circulating biomarkers of muscle atrophy, inflammation, and cartilage turnover in patients undergoing anterior cruciate ligament reconstruction and rehabilitation. Am J Sports Med 2013; 41:1819-26. [PMID: 23739685 PMCID: PMC4086614 DOI: 10.1177/0363546513490651] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND After anterior cruciate ligament (ACL) reconstruction, there is significant atrophy of the quadriceps muscles that can limit full recovery and place athletes at risk for recurrent injuries with return to play. The cause of this muscle atrophy is not fully understood. HYPOTHESIS Circulating levels of proatrophy, proinflammatory, and cartilage turnover cytokines and biomarkers would increase after ACL reconstruction. STUDY DESIGN Descriptive laboratory study. METHODS Patients (N = 18; mean age, 28 ± 2.4 years) underwent surgical reconstruction of the ACL after a noncontact athletic injury. Circulating levels of biomarkers were measured along with Short Form-12, International Knee Documentation Committee, and objective knee strength measures preoperatively and at 6 postoperative visits. Differences were tested using repeated-measures 1-way analysis of variance. RESULTS Myostatin, TGF-β, and C-reactive protein levels were significantly increased in the early postoperative period and returned to baseline. Cartilage oligomeric matrix protein levels decreased immediately after surgery and then returned to baseline. CCL2, CCL3, CCL4, CCL5, EGF, FGF-2, IGF-1, IL-10, IL-1α, IL-1β, IL-1ra, IL-6, myoglobin, and TNF-α were not different over the course of the study. CONCLUSION An increase in potent atrophy-inducing cytokines and corresponding changes in knee strength and functional scores were observed after ACL reconstruction. CLINICAL RELEVANCE Although further studies are necessary, the therapeutic inhibition of myostatin may help prevent the muscle atrophy that occurs after ACL reconstruction and provide an accelerated return of patients to sport.
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Affiliation(s)
- Christopher L Mendias
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor,Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor,Address Correspondence To: Christopher L Mendias, PhD, ATC, Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, MI 48109-2200, 734-764-3250 office, 734-647-0003 fax,
| | - Evan B Lynch
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor,Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor
| | - Max E Davis
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor
| | | | - Julie A Harning
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor
| | - Paul D DeWolf
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor
| | - Tarek A Makki
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor
| | - Asheesh Bedi
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor
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87
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Abstract
The AMP-activated protein kinase (AMPK) is a highly conserved sensor of cellular energy that appears to have arisen at an early stage during eukaryotic evolution. In 2001 it was shown to be activated by metformin, currently the major drug for treatment for type 2 diabetes. Although the known metabolic effects of AMPK activation are consistent with the idea that it mediates some of the therapeutic benefits of metformin, as discussed below it now appears unlikely that AMPK is the sole target of the drug. AMPK is also activated by several natural plant products derived from traditional medicines, and the mechanisms by which they activate AMPK are discussed. One of these is salicylate, probably the oldest medicinal agent known to humankind. The salicylate prodrug salsalate has been shown to improve metabolic parameters in subjects with insulin resistance and prediabetes, and whether this might be mediated in part by AMPK is discussed. Interestingly, there is evidence that both metformin and aspirin provide some protection against development of cancer in humans, and whether AMPK might be involved in these effects is also discussed.
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Affiliation(s)
- D Grahame Hardie
- Division of Cell Signalling and Immunology, College of Life Sciences, University of Dundee, Dundee, Scotland, UK.
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88
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Tinti M, Johnson C, Toth R, Ferrier DEK, Mackintosh C. Evolution of signal multiplexing by 14-3-3-binding 2R-ohnologue protein families in the vertebrates. Open Biol 2013; 2:120103. [PMID: 22870394 PMCID: PMC3411107 DOI: 10.1098/rsob.120103] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 06/29/2012] [Indexed: 01/09/2023] Open
Abstract
14-3-3 proteins regulate cellular responses to stimuli by docking onto pairs of phosphorylated residues on target proteins. The present study shows that the human 14-3-3-binding phosphoproteome is highly enriched in 2R-ohnologues, which are proteins in families of two to four members that were generated by two rounds of whole genome duplication at the origin of the vertebrates. We identify 2R-ohnologue families whose members share a ‘lynchpin’, defined as a 14-3-3-binding phosphosite that is conserved across members of a given family, and aligns with a Ser/Thr residue in pro-orthologues from the invertebrate chordates. For example, the human receptor expression enhancing protein (REEP) 1–4 family has the commonest type of lynchpin motif in current datasets, with a phosphorylatable serine in the –2 position relative to the 14-3-3-binding phosphosite. In contrast, the second 14-3-3-binding sites of REEPs 1–4 differ and are phosphorylated by different kinases, and hence the REEPs display different affinities for 14-3-3 dimers. We suggest a conceptual model for intracellular regulation involving protein families whose evolution into signal multiplexing systems was facilitated by 14-3-3 dimer binding to lynchpins, which gave freedom for other regulatory sites to evolve. While increased signalling complexity was needed for vertebrate life, these systems also generate vulnerability to genetic disorders.
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Affiliation(s)
- Michele Tinti
- MRC Protein Phosphorylation Unit, College of Life Sciences, James Black Centre, University of Dundee, Dow Street, Dundee DD1 5EH , UK
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89
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Richardson TG, Thomas EC, Sessions RB, Lawlor DA, Tavaré JM, Day INM. Structural and population-based evaluations of TBC1D1 p.Arg125Trp. PLoS One 2013; 8:e63897. [PMID: 23667688 PMCID: PMC3646766 DOI: 10.1371/journal.pone.0063897] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 04/09/2013] [Indexed: 12/04/2022] Open
Abstract
Obesity is now a leading cause of preventable death in the industrialised world. Understanding its genetic influences can enhance insight into molecular pathogenesis and potential therapeutic targets. A non-synonymous polymorphism (rs35859249, p.Arg125Trp) in the N-terminal TBC1D1 phosphotyrosine-binding (PTB) domain has shown a replicated association with familial obesity in women. We investigated these findings in the Avon Longitudinal Study of Parents and Children (ALSPAC), a large European birth cohort of mothers and offspring, and by generating a predicted model of the structure of this domain. Structural prediction involved the use of three separate algorithms; Robetta, HHpred/MODELLER and I-TASSER. We used the transmission disequilibrium test (TDT) to investigate familial association in the ALSPAC study cohort (N = 2,292 mother-offspring pairs). Linear regression models were used to examine the association of genotype with mean measurements of adiposity (Body Mass Index (BMI), waist circumference and Dual-energy X-ray absorptiometry (DXA) assessed fat mass), and logistic regression was used to examine the association with odds of obesity. Modelling showed that the R125W mutation occurs in a location of the TBC1D1 PTB domain that is predicted to have a function in a putative protein:protein interaction. We did not detect an association between R125W and BMI (mean per allele difference 0.27 kg/m2 (95% Confidence Interval: 0.00, 0.53) P = 0.05) or obesity (odds ratio 1.01 (95% Confidence Interval: 0.77, 1.31, P = 0.96) in offspring after adjusting for multiple comparisons. Furthermore, there was no evidence to suggest that there was familial association between R125W and obesity (χ2 = 0.06, P = 0.80). Our analysis suggests that R125W in TBC1D1 plays a role in the binding of an effector protein, but we find no evidence that the R125W variant is related to mean BMI or odds of obesity in a general population sample.
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Affiliation(s)
- Tom G Richardson
- Bristol Genetic Epidemiology Laboratories, School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol, United Kingdom.
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90
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Frøsig C, Jensen TE, Jeppesen J, Pehmøller C, Treebak JT, Maarbjerg SJ, Kristensen JM, Sylow L, Alsted TJ, Schjerling P, Kiens B, Wojtaszewski JFP, Richter EA. AMPK and insulin action--responses to ageing and high fat diet. PLoS One 2013; 8:e62338. [PMID: 23671593 PMCID: PMC3645997 DOI: 10.1371/journal.pone.0062338] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 03/20/2013] [Indexed: 12/21/2022] Open
Abstract
The 5′-AMP-activated protein kinase (AMPK) is considered “a metabolic master-switch” in skeletal muscle reducing ATP- consuming processes whilst stimulating ATP regeneration. Within recent years, AMPK has also been proposed as a potential target to attenuate insulin resistance, although the exact role of AMPK is not well understood. Here we hypothesized that mice lacking α2AMPK activity in muscle would be more susceptible to develop insulin resistance associated with ageing alone or in combination with high fat diet. Young (∼4 month) or old (∼18 month) wild type and muscle specific α2AMPK kinase-dead mice on chow diet as well as old mice on 17 weeks of high fat diet were studied for whole body glucose homeostasis (OGTT, ITT and HOMA-IR), insulin signaling and insulin-stimulated glucose uptake in muscle. We demonstrate that high fat diet in old mice results in impaired glucose homeostasis and insulin stimulated glucose uptake in both the soleus and extensor digitorum longus muscle, coinciding with reduced insulin signaling at the level of Akt (pSer473 and pThr308), TBC1D1 (pThr590) and TBC1D4 (pThr642). In contrast to our hypothesis, the impact of ageing and high fat diet on insulin action was not worsened in mice lacking functional α2AMPK in muscle. It is concluded that α2AMPK deficiency in mouse skeletal muscle does not cause muscle insulin resistance in young and old mice and does not exacerbate obesity-induced insulin resistance in old mice suggesting that decreased α2AMPK activity does not increase susceptibility for insulin resistance in skeletal muscle.
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Affiliation(s)
- Christian Frøsig
- Section of Molecular Physiology, The August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
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91
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Bijland S, Mancini SJ, Salt IP. Role of AMP-activated protein kinase in adipose tissue metabolism and inflammation. Clin Sci (Lond) 2013; 124:491-507. [PMID: 23298225 DOI: 10.1042/cs20120536] [Citation(s) in RCA: 227] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AMPK (AMP-activated protein kinase) is a key regulator of cellular and whole-body energy balance. AMPK phosphorylates and regulates many proteins concerned with nutrient metabolism, largely acting to suppress anabolic ATP-consuming pathways while stimulating catabolic ATP-generating pathways. This has led to considerable interest in AMPK as a therapeutic target for the metabolic dysfunction observed in obesity and insulin resistance. The role of AMPK in skeletal muscle and the liver has been extensively studied, such that AMPK has been demonstrated to inhibit synthesis of fatty acids, cholesterol and isoprenoids, hepatic gluconeogenesis and translation while increasing fatty acid oxidation, muscle glucose transport, mitochondrial biogenesis and caloric intake. The role of AMPK in the other principal metabolic and insulin-sensitive tissue, adipose, remains poorly characterized in comparison, yet increasing evidence supports an important role for AMPK in adipose tissue function. Obesity is characterized by hypertrophy of adipocytes and the development of a chronic sub-clinical pro-inflammatory environment in adipose tissue, leading to increased infiltration of immune cells. This combination of dysfunctional hypertrophic adipocytes and a pro-inflammatory environment contributes to insulin resistance and the development of Type 2 diabetes. Exciting recent studies indicate that AMPK may not only influence metabolism in adipocytes, but also act to suppress this pro-inflammatory environment, such that targeting AMPK in adipose tissue may be desirable to normalize adipose dysfunction and inflammation. In the present review, we discuss the role of AMPK in adipose tissue, focussing on the regulation of carbohydrate and lipid metabolism, adipogenesis and pro-inflammatory pathways in physiological and pathophysiological conditions.
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Affiliation(s)
- Silvia Bijland
- Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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92
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Friedrichsen M, Mortensen B, Pehmøller C, Birk JB, Wojtaszewski JFP. Exercise-induced AMPK activity in skeletal muscle: role in glucose uptake and insulin sensitivity. Mol Cell Endocrinol 2013; 366:204-14. [PMID: 22796442 DOI: 10.1016/j.mce.2012.06.013] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 06/21/2012] [Indexed: 12/25/2022]
Abstract
The energy/fuel sensor 5'-AMP-activated protein kinase (AMPK) is viewed as a master regulator of cellular energy balance due to its many roles in glucose, lipid, and protein metabolism. In this review we focus on the regulation of AMPK activity in skeletal muscle and its involvement in glucose metabolism, including glucose transport and glycogen synthesis. In addition, we discuss the plausible interplay between AMPK and insulin signaling regulating these processes.
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Affiliation(s)
- Martin Friedrichsen
- Molecular Physiology Group, The August Krogh Centre, Department of Exercise and Sport Sciences, University of Copenhagen, Denmark
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93
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Funai K, Song H, Yin L, Lodhi IJ, Wei X, Yoshino J, Coleman T, Semenkovich CF. Muscle lipogenesis balances insulin sensitivity and strength through calcium signaling. J Clin Invest 2013; 123:1229-40. [PMID: 23376793 DOI: 10.1172/jci65726] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 12/14/2012] [Indexed: 12/24/2022] Open
Abstract
Exogenous dietary fat can induce obesity and promote diabetes, but endogenous fat production is not thought to affect skeletal muscle insulin resistance, an antecedent of metabolic disease. Unexpectedly, the lipogenic enzyme fatty acid synthase (FAS) was increased in the skeletal muscle of mice with diet-induced obesity and insulin resistance. Skeletal muscle-specific inactivation of FAS protected mice from insulin resistance without altering adiposity, specific inflammatory mediators of insulin signaling, or skeletal muscle levels of diacylglycerol or ceramide. Increased insulin sensitivity despite high-fat feeding was driven by activation of AMPK without affecting AMP content or the AMP/ATP ratio in resting skeletal muscle. AMPK was induced by elevated cytosolic calcium caused by impaired sarco/endoplasmic reticulum calcium ATPase (SERCA) activity due to altered phospholipid composition of the sarcoplasmic reticulum (SR), but came at the expense of decreased muscle strength. Thus, inhibition of skeletal muscle FAS prevents obesity-associated diabetes in mice, but also causes muscle weakness, which suggests that mammals have retained the capacity for lipogenesis in muscle to preserve physical performance in the setting of disrupted metabolic homeostasis.
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Affiliation(s)
- Katsuhiko Funai
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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94
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Abstract
AMPK is an evolutionary conserved sensor of cellular energy status that is activated during exercise. Pharmacological activation of AMPK promotes glucose uptake, fatty acid oxidation, mitochondrial biogenesis, and insulin sensitivity; processes that are reduced in obesity and contribute to the development of insulin resistance. AMPK deficient mouse models have been used to provide direct genetic evidence either supporting or refuting a role for AMPK in regulating these processes. Exercise promotes glucose uptake by an insulin dependent mechanism involving AMPK. Exercise is important for improving insulin sensitivity; however, it is not known if AMPK is required for these improvements. Understanding how these metabolic processes are regulated is important for the development of new strategies that target obesity-induced insulin resistance. This review will discuss the involvement of AMPK in regulating skeletal muscle metabolism (glucose uptake, glycogen synthesis, and insulin sensitivity).
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Affiliation(s)
- Hayley M. O'Neill
- Protein Chemistry and Metabolism Unit, St. Vincent's Institute of Medical Research, Fitzroy, Australia
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95
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Hatakeyama H, Kanzaki M. Regulatory mode shift of Tbc1d1 is required for acquisition of insulin-responsive GLUT4-trafficking activity. Mol Biol Cell 2013; 24:809-17. [PMID: 23325788 PMCID: PMC3596251 DOI: 10.1091/mbc.e12-10-0725] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Tbc1d1 is involved in AICAR-dependent GLUT4 liberation. Tbc1d1 acquires temporal insulin responsiveness with AICAR pretreatment. This shift in regulatory mode requires Ser- 237 phosphorylation and the PTB1 domain. PTB1 mutants exhibit no shift in regulatory mode and thus no insulin responsiveness. Tbc1d1 is key to skeletal muscle GLUT4 regulation. By using GLUT4 nanometry combined with a cell-based reconstitution model, we uncover a shift in the regulatory mode of Tbc1d1 by showing that Tbc1d1 temporally acquires insulin responsiveness, which triggers GLUT4 trafficking only after an exercise-mimetic stimulus such as aminoimidazole carboxamide ribonucleotide (AICAR) pretreatment. The functional acquisition of insulin responsiveness requires Ser-237 phosphorylation and an intact phosphotyrosine-binding (PTB) 1 domain. Mutations in PTB1, including R125W (a natural mutant), thus result in complete loss of insulin-responsiveness acquisition, whereas AICAR-responsive GLUT4-liberation activity remains intact. Thus our data provide novel insights into temporal acquisition/memorization of Tbc1d1 insulin responsiveness, relying on the PTB1 domain, possibly a key factor in the beneficial effects of exercise on muscle insulin potency.
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Affiliation(s)
- Hiroyasu Hatakeyama
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi, Japan
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96
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Wang H, Ducommun S, Quan C, Xie B, Li M, Wasserman D, Sakamoto K, Mackintosh C, Chen S. AS160 deficiency causes whole-body insulin resistance via composite effects in multiple tissues. Biochem J 2013; 449:479-89. [PMID: 23078342 PMCID: PMC3685216 DOI: 10.1042/bj20120702] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 10/02/2012] [Accepted: 10/19/2012] [Indexed: 11/17/2022]
Abstract
AS160 (Akt substrate of 160 kDa) is a Rab GTPase-activating protein implicated in insulin control of GLUT4 (glucose transporter 4) trafficking. In humans, a truncation mutation (R363X) in one allele of AS160 decreased the expression of the protein and caused severe postprandial hyperinsulinaemia during puberty. To complement the limited studies possible in humans, we generated an AS160-knockout mouse. In wild-type mice, AS160 expression is relatively high in adipose tissue and soleus muscle, low in EDL (extensor digitorum longus) muscle and detectable in liver only after enrichment. Despite having lower blood glucose levels under both fasted and random-fed conditions, the AS160-knockout mice exhibited insulin resistance in both muscle and liver in a euglycaemic clamp study. Consistent with this paradoxical phenotype, basal glucose uptake was higher in AS160-knockout primary adipocytes and normal in isolated soleus muscle, but their insulin-stimulated glucose uptake and overall GLUT4 levels were markedly decreased. In contrast, insulin-stimulated glucose uptake and GLUT4 levels were normal in EDL muscle. The liver also contributes to the AS160-knockout phenotype via hepatic insulin resistance, elevated hepatic expression of phosphoenolpyruvate carboxykinase isoforms and pyruvate intolerance, which are indicative of increased gluconeogenesis. Overall, as well as its catalytic function, AS160 influences expression of other proteins, and its loss deregulates basal and insulin-regulated glucose homoeostasis, not only in tissues that normally express AS160, but also by influencing liver function.
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Key Words
- akt substrate of 160 kda (as160)
- glucose transport
- insulin resistance
- liver
- muscle
- as160, akt substrate of 160 kda
- edl, extensor digitorum longus
- fbp-1, fructose-1,6-bisphosphatase 1
- gap, gtpase-activating protein
- gapdh, glyceraldehyde-3-phosphate dehydrogenase
- gir, glucose infusion rate
- glut, glucose transporter
- gsk3, glycogen synthase kinase 3
- mbp, myelin basic protein
- pck/pepck, phosphoenolpyruvate carboxykinase
- pkb, protein kinase b
- pm, plasma membrane
- rer, respiratory exchange ratio
- ta, tibialis anterior
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Affiliation(s)
- Hong Yu Wang
- *MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing 210061, China
| | - Serge Ducommun
- †MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K
- ‡Nestlé Institute of Health Sciences SA, Campus EPFL, Quartier de l'Innovation, Bâtiment G, 1015 Lausanne, Switzerland
| | - Chao Quan
- *MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing 210061, China
| | - Bingxian Xie
- *MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing 210061, China
| | - Min Li
- *MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing 210061, China
| | - David H. Wasserman
- §Department of Molecular Physiology and Biophysics, Vanderbilt University, School of Medicine, 2200 Pierce Ave, Nashville, TN 37232, U.S.A
| | - Kei Sakamoto
- †MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K
- ‡Nestlé Institute of Health Sciences SA, Campus EPFL, Quartier de l'Innovation, Bâtiment G, 1015 Lausanne, Switzerland
| | - Carol Mackintosh
- †MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K
- ‖Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K
| | - Shuai Chen
- *MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing 210061, China
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Lansey MN, Walker NN, Hargett SR, Stevens JR, Keller SR. Deletion of Rab GAP AS160 modifies glucose uptake and GLUT4 translocation in primary skeletal muscles and adipocytes and impairs glucose homeostasis. Am J Physiol Endocrinol Metab 2012; 303:E1273-86. [PMID: 23011063 PMCID: PMC3517634 DOI: 10.1152/ajpendo.00316.2012] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Tight control of glucose uptake in skeletal muscles and adipocytes is crucial to glucose homeostasis and is mediated by regulating glucose transporter GLUT4 subcellular distribution. In cultured cells, Rab GAP AS160 controls GLUT4 intracellular retention and release to the cell surface and consequently regulates glucose uptake into cells. To determine AS160 function in GLUT4 trafficking in primary skeletal muscles and adipocytes and investigate its role in glucose homeostasis, we characterized AS160 knockout (AS160(-/-)) mice. We observed increased and normal basal glucose uptake in isolated AS160(-/-) adipocytes and soleus, respectively, while insulin-stimulated glucose uptake was impaired and GLUT4 expression decreased in both. No such abnormalities were found in isolated AS160(-/-) extensor digitorum longus muscles. In plasma membranes isolated from AS160(-/-) adipose tissue and gastrocnemius/quadriceps, relative GLUT4 levels were increased under basal conditions and remained the same after insulin treatment. Concomitantly, relative levels of cell surface-exposed GLUT4, determined with a glucose transporter photoaffinity label, were increased in AS160(-/-) adipocytes and normal in AS160(-/-) soleus under basal conditions. Insulin augmented cell surface-exposed GLUT4 in both. These observations suggest that AS160 is essential for GLUT4 intracellular retention and regulation of glucose uptake in adipocytes and skeletal muscles in which it is normally expressed. In vivo studies revealed impaired insulin tolerance in the presence of normal (male) and impaired (female) glucose tolerance. Concurrently, insulin-elicited increases in glucose disposal were abolished in all AS160(-/-) skeletal muscles and liver but not in AS160(-/-) adipose tissues. This suggests AS160 as a target for differential manipulation of glucose homeostasis.
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Affiliation(s)
- Melissa N Lansey
- Dept. of Medicine/Division of Endocrinology, Univ. of Virginia, Charlottesville, VA 22908, USA.
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Pehmøller C, Brandt N, Birk JB, Høeg LD, Sjøberg KA, Goodyear LJ, Kiens B, Richter EA, Wojtaszewski JF. Exercise alleviates lipid-induced insulin resistance in human skeletal muscle-signaling interaction at the level of TBC1 domain family member 4. Diabetes 2012; 61:2743-52. [PMID: 22851577 PMCID: PMC3478539 DOI: 10.2337/db11-1572] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Excess lipid availability causes insulin resistance. We examined the effect of acute exercise on lipid-induced insulin resistance and TBC1 domain family member 1/4 (TBCD1/4)-related signaling in skeletal muscle. In eight healthy young male subjects, 1 h of one-legged knee-extensor exercise was followed by 7 h of saline or intralipid infusion. During the last 2 h, a hyperinsulinemic-euglycemic clamp was performed. Femoral catheterization and analysis of biopsy specimens enabled measurements of leg substrate balance and muscle signaling. Each subject underwent two experimental trials, differing only by saline or intralipid infusion. Glucose infusion rate and leg glucose uptake was decreased by intralipid. Insulin-stimulated glucose uptake was higher in the prior exercised leg in the saline and the lipid trials. In the lipid trial, prior exercise normalized insulin-stimulated glucose uptake to the level observed in the resting control leg in the saline trial. Insulin increased phosphorylation of TBC1D1/4. Whereas prior exercise enhanced TBC1D4 phosphorylation on all investigated sites compared with the rested leg, intralipid impaired TBC1D4 S341 phosphorylation compared with the control trial. Intralipid enhanced pyruvate dehydrogenase (PDH) phosphorylation and lactate release. Prior exercise led to higher PDH phosphorylation and activation of glycogen synthase compared with resting control. In conclusion, lipid-induced insulin resistance in skeletal muscle was associated with impaired TBC1D4 S341 and elevated PDH phosphorylation. The prophylactic effect of exercise on lipid-induced insulin resistance may involve augmented TBC1D4 signaling and glycogen synthase activation.
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Affiliation(s)
- Christian Pehmøller
- Department of Exercise and Sport Sciences, Molecular Physiology Group, University of Copenhagen, Copenhagen, Denmark
| | - Nina Brandt
- Department of Exercise and Sport Sciences, Molecular Physiology Group, University of Copenhagen, Copenhagen, Denmark
| | - Jesper B. Birk
- Department of Exercise and Sport Sciences, Molecular Physiology Group, University of Copenhagen, Copenhagen, Denmark
| | - Louise D. Høeg
- Department of Exercise and Sport Sciences, Molecular Physiology Group, University of Copenhagen, Copenhagen, Denmark
| | - Kim A. Sjøberg
- Department of Exercise and Sport Sciences, Molecular Physiology Group, University of Copenhagen, Copenhagen, Denmark
| | - Laurie J. Goodyear
- Joslin Diabetes Center, Section on Metabolism, Harvard Medical School, Boston, Massachusetts
| | - Bente Kiens
- Department of Exercise and Sport Sciences, Molecular Physiology Group, University of Copenhagen, Copenhagen, Denmark
| | - Erik A. Richter
- Department of Exercise and Sport Sciences, Molecular Physiology Group, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen F.P. Wojtaszewski
- Department of Exercise and Sport Sciences, Molecular Physiology Group, University of Copenhagen, Copenhagen, Denmark
- Corresponding author: Jørgen F.P. Wojtaszewski,
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Balaji V, Selvaraj J, Sathish S, Mayilvanan C, Balasubramanian K. Molecular Mechanism Underlying the Antidiabetic Effects of a Siddha Polyherbal Preparation in the Liver of Type 2 Diabetic Adult Male Rats. J Evid Based Complementary Altern Med 2012. [DOI: 10.1177/2156587212460047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
A siddha polyherbal preparation consisting of 5 medicinal plants, namely, Asparagus racemosus, Emblica officinalis, Salacia oblonga, Syzygium aromaticum, and Tinospora cordifolia, in equal ratio, was formulated to examine the molecular mechanism by which it exhibits antidiabetic effects in the liver of high-fat and fructose-induced type 2 diabetic rats. The polyherbal preparation treated type 2 diabetic rats showed an increase in insulin receptor, Akt, and glucose transporter2 mRNA levels compared with diabetic rats. Insulin receptor, insulin receptor substrate-2, Akt, phosphorylated Akt substrate of 160kDaThreonine642, α-Actinin-4, β-arrestin-2, and glucose transporter2 proteins were also markedly decreased in diabetic rats, whereas the polyherbal preparation treatment significantly improved the expression of these proteins more than that of metformin-treated diabetic rats. The expression pattern of insulin signaling molecules analyzed in the present study signifies the therapeutic efficacy of the siddha polyherbal preparation.
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