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Ryu B, Ponce-Zea JE, Mai VH, Lee M, Hyun Sung S, Won Chin Y, Keun Oh W. Inhibition of protein tyrosine phosphatase 1B by serratane triterpenes from Huperzia serrata and their molecular docking study. Bioorg Med Chem Lett 2024; 111:129904. [PMID: 39069105 DOI: 10.1016/j.bmcl.2024.129904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 07/23/2024] [Accepted: 07/23/2024] [Indexed: 07/30/2024]
Abstract
During the search for protein tyrosine phosphatase 1B (PTP1B) inhibitory compounds from the natural resources, two new serratane triterpenes, 3-O-dihydro-p-coumaroyltohogenol (1) and 21-O-acetyltohogenol (2), along with four known serratane triterpenes (3-6), were isolated from the whole plant of Huperzia serrata. The chemical structures of compounds 1 and 2 were determined by NMR study, HRMS analysis, and chemical modification. All isolates were evaluated for their PTP1B inhibitory activities. Among the isolates, compounds 1, 3, 5 and 6 exhibit moderate inhibitory activities against PTP1B. Kinetic studies demonstrated that they are competitive inhibitors. Molecular docking studies support these experimental results by showing that compounds 1, 3, 5 and 6 interact with the active site of PTP1B, clarifying the structure-activity relationship. This study suggests that serratane triterpenes from H. serrata have potential as starting skeletons for anti-diabetes or anti-obesity agents.
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Affiliation(s)
- Byeol Ryu
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
| | - Jorge-Eduardo Ponce-Zea
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
| | - Van-Hieu Mai
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
| | - Mina Lee
- College of Pharmacy, Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, 255 Jungangno, Suncheon 57922, Jeonnam, Republic of Korea
| | - Sang Hyun Sung
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
| | - Young Won Chin
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
| | - Won Keun Oh
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea.
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2
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Shah A, Baiseitova A, Lee G, Kim JH, Park KH. Analogues of Dihydroflavonol and Flavone as Protein Tyrosine Phosphatase 1B Inhibitors from the Leaves of Artocarpus elasticus. ACS OMEGA 2024; 9:9053-9062. [PMID: 38434867 PMCID: PMC10905692 DOI: 10.1021/acsomega.3c07471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/18/2023] [Accepted: 02/01/2024] [Indexed: 03/05/2024]
Abstract
Protein tyrosine phosphatase 1B (PTP1B) is one of the target enzymes whose disruption leads to obesity and diabetes. A series of PTP1B inhibitors were isolated from the leaves of Artocarpus elasticus, used in traditional medicines for diabetes. The isolated inhibitors (1-13), including two new compounds (1 and 2), consisted of dihydroflavonols and flavones. The structural requirements for the PTP1B inhibitory mode and potency were revealed in both skeletons. The two highest PTP1B inhibitory properties were dihydroflavonol 1 and flavone 6 analogs with IC50 values of 0.17 and 0.79 μM, respectively. The stereochemistry also affected inhibitory potencies: trans isomer 1 (IC50= 0.17 μM) vs cis isomer 2 (IC50= 2.24 μM). Surprisingly, the dihydroflavonol and flavone glycosides (11 and 13) displayed potent inhibition with IC50s of 2.39 and 0.22 μM, respectively. Furthermore, competitive inhibitor 1 was applied to time-dependence experiments as a simple slow-binding inhibitor with parameters of Kiapp = 0.064103 μM, k3 = 0.2262 μM-1 min-1, and k4 = 0.0145 min-1. The binding affinities by using the fluorescence quenching experiment were highly correlated with inhibitory potencies: 1 (IC50= 0.17 μM, KSV = 0.4375 × 105 L·mol-1) vs 3 (IC50= 17.79 μM, KSV = 0.0006 × 105 L·mol-1). The specific binding interactions were estimated at active and allosteric sites according to the inhibitory mode by molecular docking.
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Affiliation(s)
- Abdul
Bari Shah
- Division
of Applied Life Science (BK21 Four), IALS, Gyeongsang National University, Jinju 52828, Republic
of Korea
| | - Aizhamal Baiseitova
- Division
of Applied Life Science (BK21 Four), IALS, Gyeongsang National University, Jinju 52828, Republic
of Korea
| | - Gihwan Lee
- Division
of Applied Life Science (BK21 Four), ABC-RLRC, PMBBRC, Gyeongsang National University, Jinju 52828, Korea
| | - Jeong Ho Kim
- Division
of Applied Life Science (BK21 Four), IALS, Gyeongsang National University, Jinju 52828, Republic
of Korea
| | - Ki Hun Park
- Division
of Applied Life Science (BK21 Four), IALS, Gyeongsang National University, Jinju 52828, Republic
of Korea
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3
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An in vitro and in silico α-amylase/α-glucosidase/protein tyrosine phosphatase 1 beta & radical scavenging profiling of the 3,5,7-tricarbo substituted 1H-indazoles. Med Chem Res 2022. [DOI: 10.1007/s00044-022-02972-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Xie Y, Cui Z, Wang N, Li P. Research on Potential Network Markers and Signaling Pathways in Type 2 Diabetes Based on Conditional Cell-Specific Network. Genes (Basel) 2022; 13:1155. [PMID: 35885938 PMCID: PMC9320152 DOI: 10.3390/genes13071155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/21/2022] [Accepted: 06/23/2022] [Indexed: 11/16/2022] Open
Abstract
Traditional methods concerning type 2 diabetes (T2D) are limited to grouped cells instead of each single cell, and thus the heterogeneity of single cells is erased. Therefore, it is still challenging to study T2D based on a single-cell and network perspective. In this study, we construct a conditional cell-specific network (CCSN) for each single cell for the GSE86469 dataset which is a single-cell transcriptional set from nondiabetic (ND) and T2D human islet samples, and obtain a conditional network degree matrix (CNDM). Since beta cells are the key cells leading to T2D, we search for hub genes in CCSN of beta cells and find that ATP6AP2 is essential for regulation and storage of insulin, and the renin-angiotensin system involving ATP6AP2 is related to most pathological processes leading to diabetic nephropathy. The communication between beta cells and other endocrine cells is performed and three gene pairs with obvious interaction are found. In addition, different expression genes (DEGs) are found based on CNDM and the gene expression matrix (GEM), respectively. Finally, 'dark' genes are identified, and enrichment analysis shows that NFATC2 is involved in the VEGF signaling pathway and indirectly affects the production of Prostacyclin (PGI2), which may be a potential biomarker for diabetic nephropathy.
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Affiliation(s)
| | | | | | - Peiluan Li
- School of Mathematics and Statistics, Henan University of Science and Technology, Luoyang 471023, China; (Y.X.); (Z.C.); (N.W.)
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5
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The S100B Protein and Partners in Adipocyte Response to Cold Stress and Adaptive Thermogenesis: Facts, Hypotheses, and Perspectives. Biomolecules 2020; 10:biom10060843. [PMID: 32486507 PMCID: PMC7356379 DOI: 10.3390/biom10060843] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/20/2020] [Accepted: 05/29/2020] [Indexed: 12/17/2022] Open
Abstract
In mammals, adipose tissue is an active secretory tissue that responds to mild hypothermia and as such is a genuine model to study molecular and cellular adaptive responses to cold-stress. A recent study identified a mammal-specific protein of the endoplasmic reticulum that is strongly induced in the inguinal subcutaneous white adipocyte upon exposure to cold, calsyntenin 3β (CLSTN3β). CLSTN3β regulates sympathetic innervation of thermogenic adipocytes and contributes to adaptive non-shivering thermogenesis. The calcium- and zinc-binding S100B is a downstream effector in the CLSTN3β pathways. We review, here, the literature on the transcriptional regulation of the S100b gene in adipocyte cells. We also rationalize the interactions of the S100B protein with its recognized or hypothesized intracellular (p53, ATAD3A, CYP2E1, AHNAK) and extracellular (Receptor for Advanced Glycation End products (RAGE), RPTPσ) target proteins in the context of adipocyte differentiation and adaptive thermogenesis. We highlight a chaperon-associated function for the intracellular S100B and point to functional synergies between the different intracellular S100B target proteins. A model of non-classical S100B secretion involving AHNAK/S100A10/annexin2-dependent exocytosis by the mean of exosomes is also proposed. Implications for related areas of research are noted and suggestions for future research are offered.
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Mphahlele MJ, Choong YS, Maluleka MM, Gildenhuys S. Synthesis, In Vitro Evaluation and Molecular Docking of the 5-Acetyl-2-aryl-6-hydroxybenzo[ b]furans against Multiple Targets Linked to Type 2 Diabetes. Biomolecules 2020; 10:E418. [PMID: 32156083 PMCID: PMC7175131 DOI: 10.3390/biom10030418] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/12/2020] [Accepted: 02/19/2020] [Indexed: 02/06/2023] Open
Abstract
The 5-acetyl-2-aryl-6-hydroxybenzo[b]furans 2a-h have been evaluated through in vitro enzymatic assay against targets which are linked to type 2 diabetes (T2D), namely, α-glucosidase, protein tyrosine phosphatase 1B (PTP1B) and β-secretase. These compounds have also been evaluated for antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging method. The most active compounds against α-glucosidase and/or PTP1B, namely, 4-fluorophenyl 2c, 4-methoxyphenyl 2g and 3,5-dimethoxyphenyl substituted 2h derivatives were also evaluated for potential anti-inflammatory properties against cyclooxygenase-2 activity. The Lineweaver-Burk and Dixon plots were used to determine the type of inhibition on compounds 2c and 2h against α-glucosidase and PTP1B receptors. The interactions were investigated in modelled complexes against α-glucosidase and PTP1B via molecular docking.
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Affiliation(s)
- Malose J. Mphahlele
- Department of Chemistry, University of South Africa, Private Bag X06, Florida 1710, South Africa
| | - Yee Siew Choong
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang 11800, Malaysia;
| | - Marole M. Maluleka
- Department of Chemistry, University of South Africa, Private Bag X06, Florida 1710, South Africa
| | - Samantha Gildenhuys
- Department of Life & Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Private Bag X06, Florida 1710, South Africa;
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PTPRA Phosphatase Regulates GDNF-Dependent RET Signaling and Inhibits the RET Mutant MEN2A Oncogenic Potential. iScience 2020; 23:100871. [PMID: 32062451 PMCID: PMC7021549 DOI: 10.1016/j.isci.2020.100871] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 01/15/2020] [Accepted: 01/26/2020] [Indexed: 12/17/2022] Open
Abstract
The RET proto-oncogene encodes receptor tyrosine kinase, expressed primarily in tissues of neural crest origin. De-regulation of RET signaling is implicated in several human cancers. Recent phosphatome interactome analysis identified PTPRA interacting with the neurotrophic factor (GDNF)-dependent RET-Ras-MAPK signaling-axis. Here, by identifying comprehensive interactomes of PTPRA and RET, we reveal their close physical and functional association. The PTPRA directly interacts with RET, and using the phosphoproteomic approach, we identify RET as a direct dephosphorylation substrate of PTPRA both in vivo and in vitro. The protein phosphatase domain-1 is indispensable for the PTPRA inhibitory role on RET activity and downstream Ras-MAPK signaling, whereas domain-2 has only minor effect. Furthermore, PTPRA also regulates the RET oncogenic mutant variant MEN2A activity and invasion capacity, whereas the MEN2B is insensitive to PTPRA. In sum, we discern PTPRA as a novel regulator of RET signaling in both health and cancer. PTPRA inhibits ligand (GDNF-GFRα1)-mediated RET activity on Ras-MAPK signaling axis PTPRA dephosphorylate RET on key functional phosphotyrosine sites PTPRA catalytic (PTPase) domain 1 regulates RET-driven signaling PTPRA suppresses RET oncogenic mutant MEN2A in both Ras-MAPK and cell invasion models
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Ali MY, Kim DH, Seong SH, Kim HR, Jung HA, Choi JS. α-Glucosidase and Protein Tyrosine Phosphatase 1B Inhibitory Activity of Plastoquinones from Marine Brown Alga Sargassum serratifolium. Mar Drugs 2017; 15:E368. [PMID: 29194348 PMCID: PMC5742828 DOI: 10.3390/md15120368] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/18/2017] [Accepted: 11/27/2017] [Indexed: 01/22/2023] Open
Abstract
Sargassum serratifolium C. Agardh (Phaeophyceae, Fucales) is a marine brown alga that belongs to the family Sargassaceae. It is widely distributed throughout coastal areas of Korea and Japan. S. serratifolium has been found to contain high concentrations of plastoquinones, which have strong anti-cancer, anti-inflammatory, antioxidant, and neuroprotective activity. This study aims to investigate the anti-diabetic activity of S. serratifolium and its major constituents through inhibition of protein tyrosine phosphatase 1B (PTP1B), α-glucosidase, and ONOO--mediated albumin nitration. S. serratifolium ethanolic extract and fractions exhibited broad PTP1B and α-glucosidase inhibitory activity (IC50, 1.83~7.04 and 3.16~24.16 µg/mL for PTP1B and α-glucosidase, respectively). In an attempt to identify bioactive compounds, three plastoquinones (sargahydroquinoic acid, sargachromenol and sargaquinoic acid) were isolated from the active n-hexane fraction of S. serratifolium. All three plastoquinones exhibited dose-dependent inhibitory activity against PTP1B in the IC50 range of 5.14-14.15 µM, while sargachromenol and sargaquinoic acid showed dose-dependent inhibitory activity against α-glucosidase (IC50 42.41 ± 3.09 and 96.17 ± 3.48 µM, respectively). In the kinetic study of PTP1B enzyme inhibition, sargahydroquinoic acid and sargaquinoic acid led to mixed-type inhibition, whereas sargachromenol displayed noncompetitive-type inhibition. Moreover, plastoquinones dose-dependently inhibited ONOO--mediated albumin nitration. Docking simulations of these plastoquinones demonstrated negative binding energies and close proximity to residues in the binding pocket of PTP1B and α-glucosidase, indicating that these plastoquinones have high affinity and tight binding capacity towards the active site of the enzymes. These results demonstrate that S. serratifolium and its major plastoquinones may have the potential as functional food ingredients for the prevention and treatment of type 2 diabetes.
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Affiliation(s)
- Md Yousof Ali
- Department of Food and Life Science, Pukyong National University, Busan 48513, Korea.
| | - Da Hye Kim
- Department of Food and Life Science, Pukyong National University, Busan 48513, Korea.
| | - Su Hui Seong
- Department of Food and Life Science, Pukyong National University, Busan 48513, Korea.
| | - Hyeung-Rak Kim
- Department of Food and Life Science, Pukyong National University, Busan 48513, Korea.
| | - Hyun Ah Jung
- Department of Food Science and Human Nutrition, Chonbuk National University, Jeonju 54896, Korea.
| | - Jae Sue Choi
- Department of Food and Life Science, Pukyong National University, Busan 48513, Korea.
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Tan XF, Uddin Z, Park C, Song YH, Son M, Lee KW, Park KH. Competitive protein tyrosine phosphatase 1B (PTP1B) inhibitors, prenylated caged xanthones from Garcinia hanburyi and their inhibitory mechanism. Bioorg Med Chem 2017; 25:2498-2506. [PMID: 28318895 DOI: 10.1016/j.bmc.2017.03.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 03/01/2017] [Accepted: 03/05/2017] [Indexed: 02/07/2023]
Abstract
Protein tyrosine phosphatase 1B (PTP1B) plays important role in diabetes, obesity and cancer. The methanol extract of the gum resin of Garcinia hanburyi (G. hanburyi) showed potent PTP1B inhibition at 10µg/ml. The active compounds were identified as prenylated caged xanthones (1-9) which inhibited PTP1B in dose-dependent manner. Carboxybutenyl group within caged motif (A ring) was found to play a critical role in enzyme inhibition such as 1-6 (IC50s=0.47-4.69µM), whereas compounds having hydroxymethylbutenyl 7 (IC50=70.25µM) and methylbutenyl 8 (IC50>200µM) showed less activity. The most potent inhibitor, gambogic acid 1 (IC50=0.47µM) showed 30-fold more potency than ursolic acid (IC50=15.5µM), a positive control. In kinetic study, all isolated xanthones behaved as competitive inhibitors which were fully demonstrated with Km, Vmax and Kik/Kiv ratio. It was also proved that inhibitor 1 operated under the enzyme isomerization model having k5=0.0751µM-1S-1, k6=0.0249µM-1S-1 and Kiapp=0.499µM. To develop a pharmacophore model, we explored the binding sites of compound 1 and 7 in PTP1B. These modeling results were in agreement with our findings, which revealed that the inhibitory activities are tightly related to caged motif and prenyl group in A ring.
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Affiliation(s)
- Xue Fei Tan
- Division of Applied Life Science (BK21 Plus), IALS, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Zia Uddin
- Division of Applied Life Science (BK21 Plus), IALS, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Chanin Park
- Division of Applied Life Science (BK21 Plus), PMBBRC, RINS, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Yeong Hun Song
- Division of Applied Life Science (BK21 Plus), IALS, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Minky Son
- Division of Applied Life Science (BK21 Plus), PMBBRC, RINS, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Keun Woo Lee
- Division of Applied Life Science (BK21 Plus), PMBBRC, RINS, Gyeongsang National University, Jinju 52828, Republic of Korea.
| | - Ki Hun Park
- Division of Applied Life Science (BK21 Plus), IALS, Gyeongsang National University, Jinju 52828, Republic of Korea.
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Silva FSG, Oliveira PJ, Duarte MF. Oleanolic, Ursolic, and Betulinic Acids as Food Supplements or Pharmaceutical Agents for Type 2 Diabetes: Promise or Illusion? JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:2991-3008. [PMID: 27012451 DOI: 10.1021/acs.jafc.5b06021] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Oleanolic (OA), ursolic (UA), and betulinic (BA) acids are three triterpenic acids (TAs) with potential effects for treatment of type 2 diabetes (T2DM). Mechanistic studies showed that these TAs act as hypoglycemic and antiobesity agents mainly through (i) reducing the absorption of glucose; (ii) decreasing endogenous glucose production; (iii) increasing insulin sensitivity; (iv) improving lipid homeostasis; and (v) promoting body weight regulation. Besides these promising beneficial effects, it is believed that OA, UA, and BA protect against diabetes-related comorbidities due to their antiatherogenic, anti-inflammatory, and antioxidant properties. We also highlight the protective effect of OA, UA, and BA against oxidative damage, which may be very relevant for the treatment and/or prevention of T2DM. In the present review, we provide an integrative description of the antidiabetic properties of OA, UA, and BA, evaluating the potential use of these TAs as food supplements or pharmaceutical agents to prevent and/or treat T2DM.
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Affiliation(s)
- Filomena S G Silva
- Centro de Biotecnologia Agrı́cola e Agro-Alimentar do Alentejo (CEBAL)/Instituto Politécnico de Beja (IPBeja) , Apartado 6158, 7801-908 Beja, Portugal
| | - Paulo J Oliveira
- CNC, Center for Neuroscience and Cellular Biology, UC-Biotech Building, Biocant Park, University of Coimbra , 3060-107 Cantanhede, Portugal
| | - Maria F Duarte
- Centro de Biotecnologia Agrı́cola e Agro-Alimentar do Alentejo (CEBAL)/Instituto Politécnico de Beja (IPBeja) , Apartado 6158, 7801-908 Beja, Portugal
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Krüger J, Wellnhofer E, Meyborg H, Stawowy P, Östman A, Kintscher U, Kappert K. Inhibition of Src homology 2 domain-containing phosphatase 1 increases insulin sensitivity in high-fat diet-induced insulin-resistant mice. FEBS Open Bio 2016; 6:179-89. [PMID: 27047746 PMCID: PMC4794785 DOI: 10.1002/2211-5463.12000] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/16/2015] [Accepted: 11/19/2015] [Indexed: 11/13/2022] Open
Abstract
Insulin resistance plays a crucial role in the development of type 2 diabetes. Insulin receptor signalling is antagonized and tightly controlled by protein tyrosine phosphatases (PTPs). However, the precise role of the PTP src homology 2 domain‐containing phosphatase 1 (SHP‐1) in insulin resistance has not been explored. Male C57BL/6J mice were fed a high‐fat diet (HFD, 60% kcal from fat), to induce insulin resistance, or a low‐fat diet (LFD, 10% kcal from fat) for 10 weeks. Afterwards, HFD‐fed mice were pharmacologically treated with the SHP‐1 (Ptpn6) inhibitor sodium stibogluconate and the broad spectrum pan‐PTP inhibitor bis(maltolato)oxovanadium(IV) (BMOV). Both inhibitors ameliorated the metabolic phenotype, as evidenced by reduced body weight, improved insulin sensitivity and glucose tolerance, which was not due to altered PTP gene expression. In parallel, phosphorylation of the insulin receptor and of the insulin signalling key intermediate Akt was enhanced, and both PTP inhibitors and siRNA‐mediated SHP‐1 downregulation resulted in an increased glucose uptake in vitro. Finally, recombinant SHP‐1 was capable of dephosphorylating the ligand‐induced tyrosine‐phosphorylated insulin receptor. These results indicate a central role of SHP‐1 in insulin signalling during obesity, and SHP‐1 inhibition as a potential therapeutic approach in metabolic diseases.
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Affiliation(s)
- Janine Krüger
- Center for Cardiovascular Research/CCR Institute of Laboratory Medicine Clinical Chemistry and Pathobiochemistry Charité - Universitätsmedizin Germany
| | | | - Heike Meyborg
- Department of Medicine/Cardiology Deutsches Herzzentrum Germany
| | - Philipp Stawowy
- Department of Medicine/Cardiology Deutsches Herzzentrum Germany
| | - Arne Östman
- Cancer Center Karolinska Karolinska Institutet Stockholm Sweden
| | - Ulrich Kintscher
- Center for Cardiovascular Research/CCR Institute of Pharmacology Charité - Universitätsmedizin Berlin Germany
| | - Kai Kappert
- Center for Cardiovascular Research/CCR Institute of Laboratory Medicine Clinical Chemistry and Pathobiochemistry Charité - Universitätsmedizin Germany
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12
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Shintani T, Higashi S, Takeuchi Y, Gaudio E, Trapasso F, Fusco A, Noda M. The R3 receptor-like protein tyrosine phosphatase subfamily inhibits insulin signalling by dephosphorylating the insulin receptor at specific sites. J Biochem 2015; 158:235-43. [PMID: 26063811 DOI: 10.1093/jb/mvv045] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 03/19/2015] [Indexed: 12/28/2022] Open
Abstract
The autophosphorylation of specific tyrosine residues occurs in the cytoplasmic region of the insulin receptor (IR) upon insulin binding, and this in turn initiates signal transduction. The R3 subfamily (Ptprb, Ptprh, Ptprj and Ptpro) of receptor-like protein tyrosine phosphatases (RPTPs) is characterized by an extracellular region with 6-17 fibronectin type III-like repeats and a cytoplasmic region with a single phosphatase domain. We herein identified the IR as a substrate for R3 RPTPs by using the substrate-trapping mutants of R3 RPTPs. The co-expression of R3 RPTPs with the IR in HEK293T cells suppressed insulin-induced tyrosine phosphorylation of the IR. In vitro assays using synthetic phosphopeptides revealed that R3 RPTPs preferentially dephosphorylated a particular phosphorylation site of the IR: Y960 in the juxtamembrane region and Y1146 in the activation loop. Among four R3 members, only Ptprj was co-expressed with the IR in major insulin target tissues, such as the skeletal muscle, liver and adipose tissue. Importantly, the activation of IR and Akt by insulin was enhanced, and glucose and insulin tolerance was improved in Ptprj-deficient mice. These results demonstrated Ptprj as a physiological enzyme that attenuates insulin signalling in vivo, and indicate that an inhibitor of Ptprj may be an insulin-sensitizing agent.
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Affiliation(s)
- Takafumi Shintani
- Division of Molecular Neurobiology, Department of Neurobiology, National Institute for Basic Biology, Okazaki 444-8787, Japan; Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8787, Japan
| | - Satoru Higashi
- Division of Molecular Neurobiology, Department of Neurobiology, National Institute for Basic Biology, Okazaki 444-8787, Japan; Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8787, Japan
| | - Yasushi Takeuchi
- Division of Molecular Neurobiology, Department of Neurobiology, National Institute for Basic Biology, Okazaki 444-8787, Japan
| | - Eugenio Gaudio
- Dipartimento di Medicina Sperimentale e Clinica, University Magna Græcia, Campus "S. Venuta", Catanzaro 88100, Italy; and
| | - Francesco Trapasso
- Dipartimento di Medicina Sperimentale e Clinica, University Magna Græcia, Campus "S. Venuta", Catanzaro 88100, Italy; and
| | - Alfredo Fusco
- Istituto di Endocrinologia ed Oncologia Sperimentale del CNR c/o Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Scuola di Medicina e Chirurgia di Napoli, Università degli Studi di Napoli Federico II, Napoli 80138, Italy
| | - Masaharu Noda
- Division of Molecular Neurobiology, Department of Neurobiology, National Institute for Basic Biology, Okazaki 444-8787, Japan; Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8787, Japan;
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13
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Herre DJ, Norman JB, Anderson R, Tremblay ML, Huby AC, Belin de Chantemèle EJ. Deletion of Protein Tyrosine Phosphatase 1B (PTP1B) Enhances Endothelial Cyclooxygenase 2 Expression and Protects Mice from Type 1 Diabetes-Induced Endothelial Dysfunction. PLoS One 2015; 10:e0126866. [PMID: 25974252 PMCID: PMC4431674 DOI: 10.1371/journal.pone.0126866] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 04/08/2015] [Indexed: 01/13/2023] Open
Abstract
Protein tyrosine phosphatase 1B (PTP1B) dephosphorylates receptors tyrosine kinase and acts as a molecular brake on insulin signaling pathway. Conditions of metabolic dysfunction increase PTP1B, when deletion of PTP1B protects against metabolic disorders by increasing insulin signaling. Although vascular insulin signaling contributes to the control of glucose disposal, little is known regarding the direct role of PTP1B in the control of endothelial function. We hypothesized that metabolic dysfunctions increase PTP1B expression in endothelial cells and that PTP1B deletion prevents endothelial dysfunction in situation of diminished insulin secretion. Type I diabetes (T1DM) was induced in wild-type (WT) and PTP1B-deficient mice (KO) with streptozotocin (STZ) injection. After 28 days of T1DM, KO mice exhibited a similar reduction in body weight and plasma insulin levels and a comparable increase in glycemia (WT: 384±20 vs. Ko: 432±29 mg/dL), cholesterol and triglycerides, as WT mice. T1DM increased PTP1B expression and impaired endothelial NO-dependent relaxation, in mouse aorta. PTP1B deletion did not affect baseline endothelial function, but preserved endothelium-dependent relaxation, in T1DM mice. NO synthase inhibition with L-NAME abolished endothelial relaxation in control and T1DM WT mice, whereas L-NAME and the cyclooxygenases inhibitor indomethacin were required to abolish endothelium relaxation in T1DM KO mice. PTP1B deletion increased COX-2 expression and PGI2 levels, in mouse aorta and plasma respectively, in T1DM mice. In parallel, simulation of diabetic conditions increased PTP1B expression and knockdown of PTP1B increased COX-2 but not COX-1 expression, in primary human aortic endothelial cells. Taken together these data indicate that deletion of PTP1B protected endothelial function by compensating the reduction in NO bioavailability by increasing COX-2-mediated release of the vasodilator prostanoid PGI2, in T1DM mice.
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Affiliation(s)
- David J. Herre
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States of America
| | - J. Blake Norman
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States of America
| | - Ruchi Anderson
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States of America
| | - Michel L. Tremblay
- Goodman Cancer Center and Department of Biochemistry, McGill University, Montreal, QC, Canada
| | - Anne-Cecile Huby
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States of America
| | - Eric J. Belin de Chantemèle
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States of America
- * E-mail:
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14
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Xu E, Schwab M, Marette A. Role of protein tyrosine phosphatases in the modulation of insulin signaling and their implication in the pathogenesis of obesity-linked insulin resistance. Rev Endocr Metab Disord 2014; 15:79-97. [PMID: 24264858 DOI: 10.1007/s11154-013-9282-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Insulin resistance is a major disorder that links obesity to type 2 diabetes mellitus (T2D). It involves defects in the insulin actions owing to a reduced ability of insulin to trigger key signaling pathways in major metabolic tissues. The pathogenesis of insulin resistance involves several inhibitory molecules that interfere with the tyrosine phosphorylation of the insulin receptor and its downstream effectors. Among those, growing interest has been developed toward the protein tyrosine phosphatases (PTPs), a large family of enzymes that can inactivate crucial signaling effectors in the insulin signaling cascade by dephosphorylating their tyrosine residues. Herein we briefly review the role of several PTPs that have been shown to be implicated in the regulation of insulin action, and then focus on the Src homology 2 (SH2) domain-containing SHP1 and SHP2 enzymes, since recent reports have indicated major roles for these PTPs in the control of insulin action and glucose metabolism. Finally, the therapeutic potential of targeting PTPs for combating insulin resistance and alleviating T2D will be discussed.
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Affiliation(s)
- Elaine Xu
- Department of Medicine, Cardiology Axis of the Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Ste-Foy, Québec, Canada, G1V 4G2
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15
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Guan HP, Chen G. Factors affecting insulin-regulated hepatic gene expression. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 121:165-215. [PMID: 24373238 DOI: 10.1016/b978-0-12-800101-1.00006-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Obesity has become a major concern of public health. A common feature of obesity and related metabolic disorders such as noninsulin-dependent diabetes mellitus is insulin resistance, wherein a given amount of insulin produces less than normal physiological responses. Insulin controls hepatic glucose and fatty acid metabolism, at least in part, via the regulation of gene expression. When the liver is insulin-sensitive, insulin can stimulate the expression of genes for fatty acid synthesis and suppress those for gluconeogenesis. When the liver becomes insulin-resistant, the insulin-mediated suppression of gluconeogenic gene expression is lost, whereas the induction of fatty acid synthetic gene expression remains intact. In the past two decades, the mechanisms of insulin-regulated hepatic gene expression have been studied extensively and many components of insulin signal transduction pathways have been identified. Factors that alter these pathways, and the insulin-regulated hepatic gene expression, have been revealed and the underlying mechanisms have been proposed. This chapter summarizes the recent progresses in our understanding of the effects of dietary factors, drugs, bioactive compounds, hormones, and cytokines on insulin-regulated hepatic gene expression. Given the large amount of information and progresses regarding the roles of insulin, this chapter focuses on findings in the liver and hepatocytes and not those described for other tissues and cells. Typical insulin-regulated hepatic genes, such as insulin-induced glucokinase and sterol regulatory element-binding protein-1c and insulin-suppressed cytosolic phosphoenolpyruvate carboxyl kinase and insulin-like growth factor-binding protein 1, are used as examples to discuss the mechanisms such as insulin regulatory element-mediated transcriptional regulation. We also propose the potential mechanisms by which these factors affect insulin-regulated hepatic gene expression and discuss potential future directions of the area of research.
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Affiliation(s)
- Hong-Ping Guan
- Department of Diabetes, Merck Research Laboratories, Kenilworth, New Jersey, USA
| | - Guoxun Chen
- Department of Nutrition, University of Tennessee at Knoxville, Knoxville, Tennessee, USA
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16
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Chen G. Roles of Vitamin A Metabolism in the Development of Hepatic Insulin Resistance. ISRN HEPATOLOGY 2013; 2013:534972. [PMID: 27335827 PMCID: PMC4890907 DOI: 10.1155/2013/534972] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 08/18/2013] [Indexed: 02/07/2023]
Abstract
The increase in the number of people with obesity- and noninsulin-dependent diabetes mellitus has become a major public health concern. Insulin resistance is a common feature closely associated with human obesity and diabetes. Insulin regulates metabolism, at least in part, via the control of the expression of the hepatic genes involved in glucose and fatty acid metabolism. Insulin resistance is always associated with profound changes of the expression of hepatic genes for glucose and lipid metabolism. As an essential micronutrient, vitamin A (VA) is needed in a variety of physiological functions. The active metablite of VA, retinoic acid (RA), regulates the expression of genes through the activation of transcription factors bound to the RA-responsive elements in the promoters of RA-targeted genes. Recently, retinoids have been proposed to play roles in glucose and lipid metabolism and energy homeostasis. This paper summarizes the recent progresses in our understanding of VA metabolism in the liver and of the potential transcription factors mediating RA responses. These transcription factors are the retinoic acid receptor, the retinoid X receptor, the hepatocyte nuclear factor 4α, the chicken ovalbumin upstream promoter-transcription factor II, and the peroxisome proliferator-activated receptor β/δ. This paper also summarizes the effects of VA status and RA treatments on the glucose and lipid metabolism in vivo and the effects of retinoid treatments on the expression of insulin-regulated genes involved in the glucose and fatty acid metabolism in the primary hepatocytes. I discuss the roles of RA production in the development of insulin resistance in hepatocytes and proposes a mechanism by which RA production may contribute to hepatic insulin resistance. Given the large amount of information and progresses regarding the physiological functions of VA, this paper mainly focuses on the findings in the liver and hepatocytes and only mentions the relative findings in other tissues and cells.
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Affiliation(s)
- Guoxun Chen
- Department of Nutrition, University of Tennessee at Knoxville, Knoxville, TN 37996, USA
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17
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Hendriks WJAJ, Pulido R. Protein tyrosine phosphatase variants in human hereditary disorders and disease susceptibilities. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1673-96. [PMID: 23707412 DOI: 10.1016/j.bbadis.2013.05.022] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/14/2013] [Accepted: 05/16/2013] [Indexed: 12/18/2022]
Abstract
Reversible tyrosine phosphorylation of proteins is a key regulatory mechanism to steer normal development and physiological functioning of multicellular organisms. Phosphotyrosine dephosphorylation is exerted by members of the super-family of protein tyrosine phosphatase (PTP) enzymes and many play such essential roles that a wide variety of hereditary disorders and disease susceptibilities in man are caused by PTP alleles. More than two decades of PTP research has resulted in a collection of PTP genetic variants with corresponding consequences at the molecular, cellular and physiological level. Here we present a comprehensive overview of these PTP gene variants that have been linked to disease states in man. Although the findings have direct bearing for disease diagnostics and for research on disease etiology, more work is necessary to translate this into therapies that alleviate the burden of these hereditary disorders and disease susceptibilities in man.
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Affiliation(s)
- Wiljan J A J Hendriks
- Department of Cell Biology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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18
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Variants of insulin-signaling inhibitor genes in type 2 diabetes and related metabolic abnormalities. Int J Genomics 2013; 2013:376454. [PMID: 23762820 PMCID: PMC3674720 DOI: 10.1155/2013/376454] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 04/23/2013] [Indexed: 02/08/2023] Open
Abstract
Insulin resistance has a central role in the pathogenesis of several metabolic diseases, including type 2 diabetes, obesity, glucose intolerance, metabolic syndrome, atherosclerosis, and cardiovascular diseases. Insulin resistance and related traits are likely to be caused by abnormalities in the genes encoding for proteins involved in the composite network of insulin-signaling; in this review we have focused our attention on genetic variants of insulin-signaling inhibitor molecules. These proteins interfere with different steps in insulin-signaling: ENPP1/PC-1 and the phosphatases PTP1B and PTPRF/LAR inhibit the insulin receptor activation; INPPL1/SHIP-2 hydrolyzes PI3-kinase products, hampering the phosphoinositide-mediated downstream signaling; and TRIB3 binds the serine-threonine kinase Akt, reducing its phosphorylation levels. While several variants have been described over the years for all these genes, solid evidence of an association with type 2 diabetes and related diseases seems to exist only for rs1044498 of the ENPP1 gene and for rs2295490 of the TRIB3 gene. However, overall the data recapitulated in this Review article may supply useful elements to interpret the results of novel, more technically advanced genetic studies; indeed it is becoming increasingly evident that genetic information on metabolic diseases should be interpreted taking into account the complex biological pathways underlying their pathogenesis.
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Forbes K. IFPA Gabor Than Award lecture: molecular control of placental growth: the emerging role of microRNAs. Placenta 2013; 34 Suppl:S27-33. [PMID: 23352588 DOI: 10.1016/j.placenta.2012.12.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 12/17/2012] [Accepted: 12/18/2012] [Indexed: 12/22/2022]
Abstract
Fetal growth is dependent on appropriate growth and function of the placenta. This is modulated by a variety of factors, including maternal growth factors that exert their actions by binding to specific receptors on trophoblast to promote activation of signaling events. Kinases and phosphatases within trophoblast act in concert to regulate growth factor actions and recent studies have begun to elucidate a role for microRNAs (miRs) in regulating the levels of these proteins in the placenta. This review will discuss growth factor signaling in the placenta and describe the emerging role of miRs in regulating placental development.
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Affiliation(s)
- K Forbes
- Maternal & Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester M13 0JH, United Kingdom.
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20
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Forbes K, Skinner L, Aplin JD, Westwood M. The tyrosine phosphatase SHP-1 negatively regulates cytotrophoblast proliferation in first-trimester human placenta by modulating EGFR activation. Cell Mol Life Sci 2012; 69:4029-40. [PMID: 22797910 PMCID: PMC11115170 DOI: 10.1007/s00018-012-1067-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 06/01/2012] [Accepted: 06/19/2012] [Indexed: 11/30/2022]
Abstract
Insulin-like growth factors (IGFs) influence placental cell (cytotrophoblast) kinetics. We recently reported that the protein tyrosine phosphatase (PTP) SHP-2 positively regulates IGF actions in the placenta. In other systems, the closely related PTP, SHP-1, functions as a negative regulator of signaling events but its role in the placenta is still unknown. We examined the hypothesis that SHP-1 negatively regulates IGF actions in the human placenta. Immunohistochemical (IHC) analysis demonstrated that SHP-1 is abundant in cytotrophoblast. SHP-1 expression was decreased in first-trimester placental explants using siRNA; knockdown did not alter IGF-induced proliferation but it significantly enhanced proliferation in serum-free conditions, revealing that placental growth is endogenously regulated. Candidate regulators were determined by using antibody arrays, Western blotting, and IHC to examine the activation status of multiple receptor tyrosine kinases (RTKs) in SHP-1-depleted explants; amongst the alterations observed was enhanced activation of EGFR, suggesting that SHP-1 may interact with EGFR to inhibit proliferation. The EGFR tyrosine kinase inhibitor PD153035 reversed the elevated proliferation seen in the absence of SHP-1. This study demonstrates a role for SHP-1 in human trophoblast turnover and establishes SHP-1 as a negative regulator of EGFR activation. Targeting placental SHP-1 expression may provide therapeutic benefits in common pregnancy conditions with abnormal trophoblast proliferation.
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Affiliation(s)
- Karen Forbes
- Maternal and Fetal Health Research Centre, Manchester Academic Health Sciences Centre, St Mary's Hospital, University of Manchester, School of Biomedicine, Manchester, M13 9WL, UK,
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21
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Gorgani-Firuzjaee S, Bakhtiyari S, Golestani A, Meshkani R. Leukocyte antigen-related inhibition attenuates palmitate-induced insulin resistance in muscle cells. J Endocrinol 2012; 215:71-7. [PMID: 22899729 DOI: 10.1530/joe-12-0160] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Palmitate has been shown to induce insulin resistance in skeletal muscle cells. The aim of this study was to investigate the role of the leukocyte common antigen-related (LAR) gene in palmitate-induced insulin resistance in C2C12 cells. A stable C2C12 cell line was generated using LAR short hairpin RNA. The levels of LAR protein and phosphorylation of insulin receptor substrate-1 (IRS1) and Akt were detected by western blot analysis. 2-Deoxyglucose uptake was measured in LAR knockdown and control cells using d-[2-(3)H]glucose. LAR protein level was decreased by 65% in the stable cell line compared with the control cells. Palmitate (0.5 mM) significantly induced LAR mRNA (65%) and protein levels (40%) in myotubes compared with untreated cells. Palmitate significantly reduced insulin-stimulated glucose uptake in both the control and LAR knockdown cells by 33 and 51% respectively. However, LAR depletion improved insulin-stimulated glucose uptake in myotubes treated with palmitate. Furthermore, the inhibition of LAR prevented palmitate-induced decreases in phosphorylation of IRS1(Tyr632) and Akt(Ser473) in C2C12 cells. In conclusion, these results reveal that palmitate induces LAR expression in C2C12 cells. We also provided evidence that the inhibition of LAR attenuates palmitate-induced insulin resistance in myotubes.
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Affiliation(s)
- Sattar Gorgani-Firuzjaee
- Department of Biochemistry, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran
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22
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Abstract
Insulin-like growth factor-II (IGF-II) affects many aspects of cellular function through its ability to activate several different receptors and, consequently, numerous intracellular signalling molecules. Thus, IGF-II is a key regulator of normal foetal development and growth. However, abnormalities in IGF-II function are associated with cardiovascular disease and cancer. Here, we review the cellular mechanisms by which IGF-II's physiological and pathophysiological actions are exerted by discussing the involvement of the type 1 and type 2 IGF receptors (IGF1R and IGF2R), the insulin receptor and the downstream MAP kinase, PI-3 kinase and G-protein-coupled signalling pathways in mediating IGF-II stimulated cellular proliferation, survival, differentiation and migration.
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Affiliation(s)
- Lynda K Harris
- Maternal and Fetal Health Research Centre, University of Manchester, UK
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23
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Lodeiro M, Alén BO, Mosteiro CS, Beiroa D, Nogueiras R, Theodoropoulou M, Pardo M, Gallego R, Pazos Y, Casanueva FF, Camiña JP. The SHP-1 protein tyrosine phosphatase negatively modulates Akt signaling in the ghrelin/GHSR1a system. Mol Biol Cell 2011; 22:4182-91. [PMID: 21900501 PMCID: PMC3204078 DOI: 10.1091/mbc.e11-04-0373] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The SHP-1 tyrosine phosphatase is a negative regulator of ghrelin activity, being a critical signaling component for proper regulation of Akt-dependent processes. Based on the SHP-1 expression pattern in white adipose tissue (WAT) and its regulation in a positive energy balance situation, it is possible to speculate about its role in the enlargement of WAT in obesity. The aim of the present study was to identify the signaling mechanism(s) responsible for the modulation of growth hormone secretagogue receptor type 1a (GHSR1a)-associated Akt activity. Ghrelin leads to the activation of Akt through the interplay of distinct signaling mechanisms: an early Gi/o protein-dependent pathway and a late pathway mediated by β-arrestins. We found that the Src homology 2–containing protein tyrosine phosphatase (SHP-1) was an essential molecule in both Gi/o protein–dependent and β-arrestin–mediated pathways. More specifically, the role of SHP-1 in the Gi/o protein–dependent pathway was demonstrated by the fact that the overexpression of a catalytically defective SHP-1 augments tyrosine phosphorylation of the PI3K regulatory subunit p85, leading to an increase in the phosphorylation of cSrc and phosphoinositide-dependent protein kinase 1, and finally activating Akt. The presence of SHP-1 in the β-arrestin–scaffolded complex and its attenuating effect on the cSrc and Akt activities verified that SHP-1 regulates not only the Gi/o protein–dependent pathway but also the β-arrestin–mediated pathway. Assays performed in preadipocyte and adipocyte 3T3-L1 cells showed SHP-1 expression. According to our results in HEK-GHSR1a cells, ghrelin stimulated SHP-1 phosphorylation in 3T3-L1 cells. The increase in ghrelin-induced Akt activity was enhanced by small interfering RNA of SHP-1 in preadipocyte 3T3-L1 cells. These results were reproduced in white adipose tissue obtained from mice, in which SHP-1 exhibited higher expression in omental than in subcutaneous tissue. Furthermore, this pattern of expression was inverted in mice fed a high-fat diet, suggesting a role for SHP-1 in controlling ghrelin sensitivity in adipose tissue. Indeed, SHP-1 deficiency was associated with augmented ghrelin-evoked Akt phosphorylation in omental tissue, as well as decreased phosphorylation under overexpression of SHP-1 in subcutaneous tissue. These findings showed a novel role for SHP-1 in the regulation of Akt activity through the modulation of the ghrelin/GHSR1a system signaling.
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Affiliation(s)
- Maria Lodeiro
- Área de Endocrinología Molecular y Celular, Instituto de Investigación Sanitaria de Santiago, Hospital Clinico Universitario de Santiago, Servicio Gallego de Salud, 15706 Santiago de Compostela, Spain
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24
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Tremper-Wells B, Resnick RJ, Zheng X, Holsinger LJ, Shalloway D. Extracellular domain dependence of PTPalpha transforming activity. Genes Cells 2010; 15:711-724. [PMID: 20545765 DOI: 10.1111/j.1365-2443.2010.01410.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Two isoforms of the transmembrane protein tyrosine phosphatase PTPalpha, which differ by nine amino acids in their extracellular regions, are expressed in a tissue-specific manner. Over-expression of the shorter isoform transforms rodent cells, and it has previously been reasonable to assume that this was a direct consequence of its dephosphorylation and activation of Src. Transformation by the longer wild-type isoform has not previously been studied. We tested the activities of both isoforms in NIH3T3 cells and found that, while both dephosphorylated and activated Src similarly, only the shorter isoform induced focus formation or anchorage-independent growth. Differences in phosphorylation of PTPalpha at its known regulatory sites, Grb2 binding to PTPalpha, phosphorylation level of focal adhesion kinase by PTPalpha, or overall localization were excluded as possible explanations for the differences in transforming activities. The results suggest that transformation by PTPalpha involves at least one function other than, or in addition to, its activation of Src and that this depends on PTPalpha's extracellular domain. Previous studies have suggested that PTPalpha might be a useful target in breast and colon cancer therapy, and the results presented here suggest that it may be advantageous to develop isoform-specific therapeutic reagents.
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Affiliation(s)
- Barbara Tremper-Wells
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Ross J Resnick
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Xinmin Zheng
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | | | - David Shalloway
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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25
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Forbes K, West G, Garside R, Aplin JD, Westwood M. The protein-tyrosine phosphatase, SRC homology-2 domain containing protein tyrosine phosphatase-2, is a crucial mediator of exogenous insulin-like growth factor signaling to human trophoblast. Endocrinology 2009; 150:4744-54. [PMID: 19589868 DOI: 10.1210/en.2009-0166] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Adequate fetal growth depends on placental transfer of nutrients and gases from the mother; thus, as pregnancy progresses, the placenta must grow to meet the increasing demands of the developing fetus. IGFs control proliferation, differentiation, and survival of trophoblast in first-trimester placenta via intracellular tyrosine kinase signaling cascades, the activation of which is also regulated by tyrosine phosphatases. The protein-tyrosine phosphatase, Src homology-2 domain containing protein tyrosine phosphatase (SHP)-2, is crucial for mouse placental development and is known to mediate IGF actions in other systems. In this study we examined the role of SHP-2 in regulating IGF-mediated proliferation in human trophoblast. Immunohistochemical analysis demonstrated that SHP-2 is expressed strongly in cytotrophoblast and only weakly in syncytium. After small interfering RNA-mediated knockdown of SHP-2 in BeWo choriocarcinoma cells and human first-trimester placental explants, IGF-induced trophoblast proliferation, examined using immunohistochemical analysis of Ki67 and 5-bromo-2'-deoxyuridine incorporation, was significantly reduced (P < 0.05). Kinase activation assays suggested that SHP-2 interacts with the MAPK pathway to mediate these effects. Markers of trophoblast differentiation were elevated after SHP-2 knockdown. This study demonstrates a role for tyrosine phosphatases in human trophoblast and establishes SHP-2 as a component of the IGF signaling pathway that is required for normal placental growth.
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Affiliation(s)
- Karen Forbes
- Maternal and Fetal Health Research Group, University of Manchester, Manchester M13 0JH, United Kingdom
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26
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Expression of pleiotrophin and its receptors in human placenta suggests roles in trophoblast life cycle and angiogenesis. Placenta 2009; 30:649-53. [PMID: 19481257 DOI: 10.1016/j.placenta.2009.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Revised: 04/28/2009] [Accepted: 05/01/2009] [Indexed: 11/22/2022]
Abstract
Pleiotrophin (PTN) is a heparin-binding protein with multiple activities in cell growth, migration and differentiation mediated through multiple receptors. In mammals, PTN expression in trophoblast is found exclusively in the human and in some of the apes in which an endogenous retrovirus upstream of the first coding exon generates a phylogenetically new trophoblast-specific promoter associated with exon UV3. To understand the functions of ERV promoter-mediated trophoblastic PTN expression in pregnancy, we correlated the expression of PTN and its receptors anaplastic lymphoma kinase (ALK), receptor protein tyrosine phosphatase beta/zeta (RPTPbeta/zeta), and Syndecan-1 and Syndecan-3 (SDC1 and SDC3) with key developmental processes in first-trimester human placentation. In an extensive survey of cell lines and primary tissues, we found that trophoblastic transcription of PTN is initiated exclusively from the ERV promoter, whereas decidual expression is initiated at the phylogenetically ancient U1 exon-associated promoter. Using immunohistochemistry, we found that different patterns of overlapping expression of PTN and its receptors occur in different trophoblast subtypes. Notably, a role in angiogenesis is supported by expression of PTN and its receptors in villous mesenchyme, fetal macrophages and villus core fetal vessels. PTN staining of extravillous cytotrophoblasts and the syncytial microvillous membrane is consistent with increasing levels of PTN, as measured by ELISA, in the maternal bloodstream as pregnancy progresses.
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27
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Shi L, Zhang W, Zhou YY, Zhang YN, Li JY, Hu LH, Li J. Corosolic acid stimulates glucose uptake via enhancing insulin receptor phosphorylation. Eur J Pharmacol 2008; 584:21-9. [DOI: 10.1016/j.ejphar.2008.01.020] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2007] [Revised: 12/23/2007] [Accepted: 01/15/2008] [Indexed: 11/25/2022]
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28
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Kapp K, Siemens J, Weyrich P, Schulz JB, Häring HU, Lammers R. Extracellular domain splice variants of a transforming protein tyrosine phosphatase alpha mutant differentially activate Src-kinase dependent focus formation. Genes Cells 2007; 12:63-73. [PMID: 17212655 DOI: 10.1111/j.1365-2443.2006.01034.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The extracellular domains of receptor-type protein-tyrosine phosphatases (PTPs) contain a diverse range of protein modules like fibronectin- or immunoglobulin-like structures. These are frequently expressed in a tissue- and development specific manner as splice variants. The extracellular domain of PTPalpha is rather short and heavily glycosylated. Two splice variants are known, which it differs by an exon encoding nine amino acids within the extracellular domain. We have analyzed the expression pattern of both variants and found that the smaller form is ubiquitously expressed while the larger form was found at an increased level only in brain, some skeletal muscle and differentiating cells like granule neurons, adipocytes and myotubes. The phosphatase activity of both forms was similar when tested in vitro using para-nitrophenylphosphate as a substrate and in a transient expression system with the substrates c-Fyn or c-Src. In a quantitative focus formation assay the capability of the larger form to activate Src-dependent focus formation in intact cells was increased more than twofold whereas the capability to dephosphorylate the insulin receptor in a BHK cell system was similar. We conclude that the two splice variants of PTPalpha are expressed differentially and regulate c-Src activity in different ways.
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Affiliation(s)
- Katja Kapp
- Medical Clinic IV, Otfried-Müller Str.10, 72076 Tübingen, Germany
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Wan ZK, Lee J, Xu W, Erbe DV, Joseph-McCarthy D, Follows BC, Zhang YL. Monocyclic thiophenes as protein tyrosine phosphatase 1B inhibitors: Capturing interactions with Asp48. Bioorg Med Chem Lett 2006; 16:4941-5. [PMID: 16806920 DOI: 10.1016/j.bmcl.2006.06.051] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2006] [Revised: 06/13/2006] [Accepted: 06/14/2006] [Indexed: 11/21/2022]
Abstract
A series of monocyclic thiophenes was designed and synthesized as PTP1B inhibitors. Guided by X-ray co-crystal structural information and computational modeling, rational design led to key interactions with Asp48 and improved inhibitory potency against PTP1B.
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Affiliation(s)
- Zhao-Kui Wan
- Chemical and Screening Sciences, Wyeth Research, 200 Cambridge Park Drive, Cambridge, MA 02140, USA
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30
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Chagnon MJ, Elchebly M, Uetani N, Dombrowski L, Cheng A, Mooney RA, Marette A, Tremblay ML. Altered glucose homeostasis in mice lacking the receptor protein tyrosine phosphatase sigmaThis paper is one of a selection of papers published in this Special issue, entitled Second Messengers and Phosphoproteins—12th International Conference. Can J Physiol Pharmacol 2006; 84:755-63. [PMID: 16998539 DOI: 10.1139/y06-020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Several protein tyrosine phosphatases (PTPs) expressed in insulin sensitive-tissues are proposed to attenuate insulin action and could act as key regulators of the insulin receptor (IR) signaling pathway. Among these PTPs, RPTPσ is expressed in relatively high levels in insulin-target tissues. We show that RPTPσ−/− knockout mice have reduced plasma glucose and insulin concentrations in the fasted state compared with their wild-type siblings. The knockout animals were also more sensitive to exogenous insulin as assayed by insulin-tolerance tests. Despite increased whole-body insulin sensitivity, tyrosine phosphorylation of the IR was not increased in muscle of RPTPσ−/− animals, as would be expected in insulin-sensitive animals. Instead, the levels of IR tyrosine phosphorylation and PI3-kinase activity were reduced in the muscle of knockout animals stimulated with insulin in vivo. However, insulin-stimulated Akt serine phosphorylation was essentially identical between both groups of mice. Accordingly, muscles isolated from RPTPσ−/− mice did not have a significant increase in glucose uptake in response to insulin, suggesting that RPTPσ did not play a direct role in this process. Taken together, our results suggest an indirect modulation of the IR signaling pathways by RPTPσ. Since low dose injection of growth hormone (GH) normalized the response to exogenous insulin in RPTPσ−/− mice, we propose that the insulin hypersensitivity observed in RPTPσ−/− mice is secondary to their neuroendocrine dysplasia and GH/IGF-1 deficiency.
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Affiliation(s)
- Mélanie J Chagnon
- McGill Cancer Centre and Department of Biochemistry, McIntyre Medical Sciences Building, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC H3G 1Y6, Canada
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31
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Das D, Nahlé Z, Zhang MQ. Adaptively inferring human transcriptional subnetworks. Mol Syst Biol 2006; 2:2006.0029. [PMID: 16760900 PMCID: PMC1681499 DOI: 10.1038/msb4100067] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2005] [Accepted: 03/28/2006] [Indexed: 12/21/2022] Open
Abstract
Although the human genome has been sequenced, progress in understanding gene regulation in humans has been particularly slow. Many computational approaches developed for lower eukaryotes to identify cis-regulatory elements and their associated target genes often do not generalize to mammals, largely due to the degenerate and interactive nature of such elements. Motivated by the switch-like behavior of transcriptional responses, we present a systematic approach that allows adaptive determination of active transcriptional subnetworks (cis-motif combinations, the direct target genes and physiological processes regulated by the corresponding transcription factors) from microarray data in mammals, with accuracy similar to that achieved in lower eukaryotes. Our analysis uncovered several new subnetworks active in human liver and in cell-cycle regulation, with similar functional characteristics as the known ones. We present biochemical evidence for our predictions, and show that the recently discovered G2/M-specific E2F pathway is wider than previously thought; in particular, E2F directly activates certain mitotic genes involved in hepatocellular carcinomas. Additionally, we demonstrate that this method can predict subnetworks in a condition-specific manner, as well as regulatory crosstalk across multiple tissues. Our approach allows systematic understanding of how phenotypic complexity is regulated at the transcription level in mammals and offers marked advantage in systems where little or no prior knowledge of transcriptional regulation is available.
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Affiliation(s)
- Debopriya Das
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Zaher Nahlé
- Department of Internal Medicine, Center for Human Nutrition, Washington University in St Louis, St Louis, MO, USA
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32
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Lok CAR, Böing AN, Reitsma PH, van der Post JAM, van Bavel E, Boer K, Sturk A, Nieuwland R. Expression of inflammation-related genes in endothelial cells is not directly affected by microparticles from preeclamptic patients. ACTA ACUST UNITED AC 2006; 147:310-20. [PMID: 16750669 DOI: 10.1016/j.lab.2006.02.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Revised: 01/06/2006] [Accepted: 02/02/2006] [Indexed: 11/18/2022]
Abstract
BACKGROUND Inflammation and endothelial dysfunction are prominent in preeclampsia. Microparticles (MPs) may link these processes, as MPs induce the production of pro-inflammatory cytokines by endothelial cells and cause endothelial dysfunction. AIM To study changes in expression of inflammation-related genes in human endothelial cells in response to MPs from preeclamptic patients. METHODS Human umbilical vein endothelial cells (HUVECs) were incubated for various time intervals in the absence or presence of isolated MP fractions from preeclamptic patients (n = 3), normotensive pregnant women (n = 3), non-pregnant controls (n = 3), and interleukin (IL)-1alpha as a positive control. Total RNA was isolated and used for multiplex ligation-dependent probe amplification (MLPA) and real-time polymerase chain reaction (PCR). RESULTS IL-1alpha enhanced the expression of IL-1alpha, IL-2, IL-6, and IL-8; nuclear factor of kappa light chain enhancer in B-cells (NFkappaB)-1, NFkappaB-2, and NFkappaB-inhibitor; cyclin-dependent kinase inhibitor and monocyte chemotactic protein-1; and transiently increased tissue factor expression. RNA expression of inflammation-related genes and genes encoding adhesion receptors, however, were unaffected by any of the MP fractions tested. CONCLUSION MLPA is a suitable assay to test the inflammatory status of endothelial cells, because incubation with IL-1alpha triggered substantial changes in RNA expression in endothelial cells. Taken together, it seems unlikely that MPs from preeclamptic patients induce endothelial dysfunction by directly affecting the expression of inflammation-related genes in these cells.
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Dubois MJ, Bergeron S, Kim HJ, Dombrowski L, Perreault M, Fournès B, Faure R, Olivier M, Beauchemin N, Shulman GI, Siminovitch KA, Kim JK, Marette A. The SHP-1 protein tyrosine phosphatase negatively modulates glucose homeostasis. Nat Med 2006; 12:549-56. [PMID: 16617349 DOI: 10.1038/nm1397] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2005] [Accepted: 03/17/2006] [Indexed: 12/17/2022]
Abstract
The protein tyrosine phosphatase SHP-1 is a well-known inhibitor of activation-promoting signaling cascades in hematopoietic cells but its potential role in insulin target tissues is unknown. Here we show that Ptpn6(me-v/me-v) (also known as viable motheaten) mice bearing a functionally deficient SHP-1 protein are markedly glucose tolerant and insulin sensitive as compared to wild-type littermates, as a result of enhanced insulin receptor signaling to IRS-PI3K-Akt in liver and muscle. Downregulation of SHP-1 activity in liver of normal mice by adenoviral expression of a catalytically inert mutant of SHP-1, or after small hairpin RNA-mediated SHP-1 silencing, further confirmed this phenotype. Tyrosine phosphorylation of CEACAM1, a modulator of hepatic insulin clearance, and clearance of serum [125I]-insulin were markedly increased in SHP-1-deficient mice or SHP-1-deficient hepatic cells in vitro. These findings show a novel role for SHP-1 in the regulation of glucose homeostasis through modulation of insulin signaling in liver and muscle as well as hepatic insulin clearance.
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Affiliation(s)
- Marie-Julie Dubois
- Department of Anatomy-Physiology and Lipid Research Unit, Laval University Hospital Research Center, 2705 Laurier Boulevard, Québec, Québec G1V 4G2, Canada
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34
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Lajus S, Lang J. Splice variant 3, but not 2 of receptor protein-tyrosine phosphatase σ can mediate stimulation of insulin-secretion by α-latrotoxin. J Cell Biochem 2006; 98:1552-9. [PMID: 16552719 DOI: 10.1002/jcb.20871] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Alpha-latrotoxin (alpha-LTX) binds to several cell surface receptors including receptor protein-tyrosine phosphatase sigma (RPTPsigma). Here we demonstrate that transient overexpression of the short splice variant 3 conferred alpha-LTX induced secretion to hamster insulinoma (HIT-15) cells. In contrast, the long splice variant 2 containing four additional extracellular fibronectin-III domains was inactive in secretion or in a single cell assay. Toxin-sensitive (MIN6) and toxin-insensitive (HIT-T15) insulinoma cell lines as well as PC12 cells expressed similar amounts of endogenous short RPTPsigma splice variant suggesting that this receptor does not play a role for toxin-sensitivity.
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Affiliation(s)
- Sophie Lajus
- Institut Européen de Chimie et Biologie, JE 2390, F-33607 Bordeaux/Pessac, France
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35
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Yang X, Li J, Zhou Y, Shen Q, Chen J, Li J. Discovery of novel inhibitor of human leukocyte common antigen-related phosphatase. Biochim Biophys Acta Gen Subj 2005; 1726:34-41. [PMID: 16198483 DOI: 10.1016/j.bbagen.2005.07.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Revised: 06/23/2005] [Accepted: 07/08/2005] [Indexed: 11/18/2022]
Abstract
Human leukocyte common antigen-related phosphatase (LAR) may play a role in type 2 diabetes and cancer, and in the development of the nervous system, and it may be an attractive target for the treatment of diabetes and cancer. We identified eight hits from the random screening of LAR D1 with a high-throughput screening assay. Further validation of the eight hits showed that the meD insertion was associated with inhibition of LAR D1D2 and LAR D1Q. These data suggest that the inserted meD peptide influences the interaction of the enzyme and inhibitor, which is consistent with the kinetic catalysis constants of the substrate pNPP. Our data showed that Hit 1, the first published novel inhibitor of LAR, is a competitive inhibitor with a K(i) of 330 nM that displays obvious selectivity for LAR and mouse PTPsigma, but not for other protein tyrosine phosphatases.
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Affiliation(s)
- Xiaoning Yang
- East China Normal University, Academy of Life Science, Shanghai 200062, P. R. China
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36
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Nakagawa Y, Aoki N, Aoyama K, Shimizu H, Shimano H, Yamada N, Miyazaki H. Receptor-Type Protein Tyrosine Phosphatase ε (PTPεM) is a Negative Regulator of Insulin Signaling in Primary Hepatocytes and Liver. Zoolog Sci 2005; 22:169-75. [PMID: 15738637 DOI: 10.2108/zsj.22.169] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Impaired insulin receptor (IR) signaling leads to insulin resistance and type 2 diabetes mellitus. Several inhibitors of the IR tyrosine kinase activity have recently been described and associated with human insulin resistance. Among these negative regulators, protein tyrosine phosphatases (PTPs) are likely to play a pivotal role in IR signaling. Transgenic studies revealed that PTP1B and TCPTP are primary candidates but IR of these animals can be finally dephosphorylated, suggesting that other PTPs are also involved in the dephosphorylation of IR. In this study, we showed that receptor-type PTPepsilon (PTP epsilonM) dephosphorylated IR in rat primary hepatocytes and tyrosines 972, 1158, 1162 and 1163 were primary targets of PTP epsilonM. Wild type as well as substrate-trapping DA forms of PTPepsilonM suppressed phosphorylation of IR downstream enzymes such as Akt, extracellular regulated kinase (ERK) and glycogen synthase kinase 3 (GSK3). It was also demonstrated that PTPepsilonM suppressed insulin-induced glycogen synthesis and inhibited insulin-induced suppression of phosphoenol pyruvate carboxykinase (PEPCK) expression in primary hepatocytes. Furthermore, adenovirally introduced PTPepsilonM also exhibited inhibitory activity against suppression of PEPCK expression in mouse liver. These results suggest that PTPepsilonM is a negative regulator of IR signaling and involved in insulin-induced glucose metabolism mainly through direct dephosphorylation and inactivation of IR in hepatocytes and liver.
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37
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Chagnon MJ, Uetani N, Tremblay ML. Functional significance of the LAR receptor protein tyrosine phosphatase family in development and diseases. Biochem Cell Biol 2004; 82:664-75. [PMID: 15674434 DOI: 10.1139/o04-120] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The protein tyrosine phosphatases (PTPs) have emerged as critical players in diverse cellular functions. The focus of this review is the leukocyte common antigen-related (LAR) subfamily of receptor PTPs (RPTPs). This subfamily is composed of three vertebrate homologs, LAR, RPTP-sigma, and RPTP-delta, as well as few invertebrates orthologs such as Dlar. LAR-RPTPs have a predominant function in nervous system development that is conserved throughout evolution. Proteolytic cleavage of LAR-RPTP proproteins results in the noncovalent association of an extracellular domain resembling cell adhesion molecules and intracellular tandem PTPs domains, which is likely regulated via dimerization. Their receptor-like structures allow them to sense the extracellular environment and transduce signals intracellularly via their cytosolic PTP domains. Although many interacting partners of the LAR-RPTPs have been identified and suggest a role for the LAR-RPTPs in actin remodeling, very little is known about the mechanisms of action of RPTPs. LAR-RPTPs recently raised a lot of interest when they were shown to regulate neurite growth and nerve regeneration in transgenic animal models. In addition, LAR-RPTPs have also been implicated in metabolic regulation and cancer. This RPTP subfamily is likely to become important as drug targets in these various human pathologies, but further understanding of their complex signal transduction cascades will be required.Key words: protein tyrosine phosphatase, LAR, signal transduction, nervous system development.
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Affiliation(s)
- Mélanie J Chagnon
- McGill Cancer Centre and Department of Biochemistry, McGill University, McIntyre Medical Sciences Building, 3655 Promenade Sir-William-Osler, Room 701, Montréal, QC H3G 1Y6, Canada
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38
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Bernier M. Protein tyrosine phosphatases. Cell Biochem Biophys 2004. [DOI: 10.1385/cbb:40:3:209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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39
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Protein tyrosine phosphatases. Cell Biochem Biophys 2004. [DOI: 10.1007/bf02739025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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40
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A receptor-like inositol lipid phosphatase is required for the maturation of developing cochlear hair bundles. J Neurosci 2003. [PMID: 14534255 DOI: 10.1523/jneurosci.23-27-09208.2003] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A screen for protein tyrosine phosphatases (PTPs) expressed in the chick inner ear yielded a high proportion of clones encoding an avian ortholog of protein tyrosine phosphatase receptor Q (Ptprq), a receptor-like PTP. Ptprq was first identified as a transcript upregulated in rat kidney in response to glomerular nephritis and has recently been shown to be active against inositol phospholipids. An antibody to the intracellular domain of Ptprq, anti-Ptprq, stains hair bundles in mice and chicks. In the chick ear, the distribution of Ptprq is almost identical to that of the 275 kDa hair-cell antigen (HCA), a component of hair-bundle shaft connectors recognized by a monoclonal antibody (mAb) that stains inner-ear hair bundles and kidney glomeruli. Furthermore, anti-Ptprq immunoblots a 275 kDa polypeptide immunoprecipitated by the anti-HCA mAb from the avian inner ear, indicating that the HCA and Ptprq are likely to be the same molecule. In two transgenic mouse strains with different mutations in Ptprq, anti-Ptprq immunoreactivity cannot be detected in the ear. Shaft connectors are absent from mutant vestibular hair bundles, but the stereocilia forming the hair bundle are not splayed, indicating that shaft connectors are not necessary to hold the stereocilia together; however, the mice show rapid postnatal deterioration in cochlear hair-bundle structure, associated with smaller than normal transducer currents with otherwise normal adaptation properties, a progressive loss of basal-coil cochlear hair cells, and deafness. These results reveal that Ptprq is required for formation of the shaft connectors of the hair bundle, the normal maturation of cochlear hair bundles, and the long-term survival of high-frequency auditory hair cells.
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41
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Cheng A, Dubé N, Gu F, Tremblay ML. Coordinated action of protein tyrosine phosphatases in insulin signal transduction. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:1050-9. [PMID: 11856336 DOI: 10.1046/j.0014-2956.2002.02756.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Insulin is the principal regulatory hormone involved in the tight regulation of fuel metabolism. In response to blood glucose levels, it is secreted by the beta cells of the pancreas and exerts its effects by binding to cell surface receptors that are present on virtually all cell types and tissues. In humans, perturbations in insulin function and/or secretion lead to diabetes mellitus, a severe disorder primarily characterized by an inability to maintain blood glucose homeostasis. Furthermore, it is estimated that 90-95% of diabetic patients exhibit resistance to insulin action. Thus an understanding of insulin signal transduction and insulin resistance at the molecular level is crucial to the understanding of the pathogenesis of this disease. The insulin receptor (IR) is a transmembrane tyrosine kinase that becomes activated upon ligand binding. Consequently, the receptor and its downstream substrates become tyrosine phosphorylated. This activates a series of intracellular signaling cascades which coordinately initiate the appropriate biological response. One important mechanism by which insulin signaling is regulated involves the protein tyrosine phosphatases (PTPs), which may either act on the IR itself and/or its substrates. Two well characterized examples include leuckocyte antigen related (LAR) and protein tyrosine phosphatase-1B (PTP-1B). The present review will discuss the current knowledge of these two and other potential PTPs involved in the insulin signaling pathway.
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Affiliation(s)
- Alan Cheng
- Department of Biochemistry and McGill Cancer Center, McGill University, Montreal, Quebec, Canada
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42
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McArdle L, Rafferty M, Maelandsmo GM, Bergin O, Farr CJ, Dervan PA, O'Loughlin S, Herlyn M, Easty DJ. Protein tyrosine phosphatase genes downregulated in melanoma. J Invest Dermatol 2001; 117:1255-60. [PMID: 11710941 DOI: 10.1046/j.0022-202x.2001.01534.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Phospho-tyrosine levels are increased in melanoma, apparently consistent with reports of elevated protein tyrosine kinase activity. Some protein tyrosine kinases are encoded by oncogenes and have been implicated in melanoma genesis. Decreased protein tyrosine phosphatase activity may also increase phospho-tyrosine. Protein tyrosine phosphatase genes are candidate tumor suppressors and loss of expression may contribute to melanoma genesis. Here we survey protein tyrosine phosphatase expression in pigment cells. Protein tyrosine phosphatase genes were cloned by reverse transcriptase polymerase chain reaction using degenerate primers based upon conserved sequences within the phosphatase catalytic domain. Reaction products were cloned and sequenced: 118 and 113 partial protein tyrosine phosphatase products were isolated from normal melanocytes and melanoma cells, respectively. Northern blotting analysis was used to study expression of 15 protein tyrosine phosphatase genes. Expression of PTP-kappa and PTP-pi was absent or downregulated in more than 20% of melanoma cell lines and in some unmanipulated melanoma biopsies. These closely related enzymes are members of the 2B receptor protein tyrosine phosphatase family previously implicated in contact inhibition. Loss of protein tyrosine phosphatase expression may contribute to the abnormal tyrosine phosphorylation seen in melanoma; these genes are candidate tumor suppressors.
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Affiliation(s)
- L McArdle
- Department of Pathology, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
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43
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Abstract
A role for protein tyrosine phosphatases in the negative regulation of insulin signaling and a putative involvement in the insulin resistance associated with type 2 diabetes have been postulated since their discovery. The recent demonstration that mice lacking the protein tyrosine phosphatase-1B (PTP-1B) have enhanced insulin sensitivity validates this. Furthermore, when fed a high fat diet, these mice maintained insulin sensitivity and were resistant to obesity, suggesting that inhibition of PTP-1B activity could be a novel way of treating type 2 diabetes and obesity. This commentary reviews our current knowledge of PTP-1B in insulin signaling and its role in diabetes and discusses the development of potent and selective PTP-1B inhibitors.
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Affiliation(s)
- B P Kennedy
- Department of Biochemistry and Molecular Biology, Merck Frosst Center for Therapeutic Research, Pointe Claire-Dorval, H9R 4P8, Quebec, Canada.
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44
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Wälchli S, Curchod ML, Gobert RP, Arkinstall S, Hooft van Huijsduijnen R. Identification of tyrosine phosphatases that dephosphorylate the insulin receptor. A brute force approach based on "substrate-trapping" mutants. J Biol Chem 2000; 275:9792-6. [PMID: 10734133 DOI: 10.1074/jbc.275.13.9792] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Many pharmacologically important receptors, including all cytokine receptors, signal via tyrosine (auto)phosphorylation, followed by resetting to their original state through the action of protein tyrosine phosphatases (PTPs). Establishing the specificity of PTPs for receptor substrates is critical both for understanding how signaling is regulated and for the development of specific PTP inhibitors that act as ligand mimetics. We have set up a systematic approach for finding PTPs that are specific for a receptor and have validated this approach with the insulin receptor kinase. We have tested nearly all known human PTPs (45) in a membrane binding assay, using "substrate-trapping" PTP mutants. These results, combined with secondary dephosphorylation tests, confirm and extend earlier findings that PTP-1b and T-cell PTP are physiological enzymes for the insulin receptor kinase. We demonstrate that this approach can rapidly reduce the number of PTPs that have a particular receptor or other phosphoprotein as their substrate.
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Affiliation(s)
- S Wälchli
- Serono Pharmaceutical Research Institute, 14, chemin des Aulx, 1228 Plan-les-Ouates, Geneva 1228, Switzerland
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45
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Suárez Pestana E, Tenev T, Gross S, Stoyanov B, Ogata M, Böhmer FD. The transmembrane protein tyrosine phosphatase RPTPsigma modulates signaling of the epidermal growth factor receptor in A431 cells. Oncogene 1999; 18:4069-79. [PMID: 10435588 DOI: 10.1038/sj.onc.1202794] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Attenuation of epidermal growth factor receptor signaling by the ganglioside G(M3) has previously been found to involve activation of an unknown protein-tyrosine phosphatase (PTP). In transient expression experiments we tested different PTPs for activation towards EGF receptor by G(M3). The transmembrane PTP RPTPsigma but not RPTPalpha or the SH2-domain PTP SHP-1 exhibited elevated activity towards EGF receptor in G(M3)-treated cells. The possible relevance of RPTPsigma for regulation of EGF receptor signaling activity was further explored in stable A431 cells lines inducibly expressing RPTPsigma or RPTPsigma antisense RNA. RPTPsigma expression clearly reduced EGF receptor phosphorylation. Also, soft agar colony formation of respective cell lines was reduced upon RPTPsigma expression whereas RPTPsigma antisense RNA expression augmented both, EGF receptor phosphorylation and soft agar colony formation. In addition, RPTPsigma antisense RNA expression rendered A431 cells resistant to inhibition of EGF receptor phosphorylation by G(M3). We propose that RPTPsigma participates in EGF receptor dephosphorylation in A431 cells, becomes activated by G(M3) via an unknown mechanism and is thereby capable to mediate attenuation of EGF receptor phosphorylation by G(M3).
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Affiliation(s)
- E Suárez Pestana
- Research Unit 'Molecular Cell Biology', Klinikum der Friedrich-Schiller Universität Jena, Germany
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46
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Elchebly M, Payette P, Michaliszyn E, Cromlish W, Collins S, Loy AL, Normandin D, Cheng A, Himms-Hagen J, Chan CC, Ramachandran C, Gresser MJ, Tremblay ML, Kennedy BP. Increased insulin sensitivity and obesity resistance in mice lacking the protein tyrosine phosphatase-1B gene. Science 1999; 283:1544-8. [PMID: 10066179 DOI: 10.1126/science.283.5407.1544] [Citation(s) in RCA: 1662] [Impact Index Per Article: 66.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Protein tyrosine phosphatase-1B (PTP-1B) has been implicated in the negative regulation of insulin signaling. Disruption of the mouse homolog of the gene encoding PTP-1B yielded healthy mice that, in the fed state, had blood glucose concentrations that were slightly lower and concentrations of circulating insulin that were one-half those of their PTP-1B+/+ littermates. The enhanced insulin sensitivity of the PTP-1B-/- mice was also evident in glucose and insulin tolerance tests. The PTP-1B-/- mice showed increased phosphorylation of the insulin receptor in liver and muscle tissue after insulin injection in comparison to PTP-1B+/+ mice. On a high-fat diet, the PTP-1B-/- and PTP-1B+/- mice were resistant to weight gain and remained insulin sensitive, whereas the PTP-1B+/+ mice rapidly gained weight and became insulin resistant. These results demonstrate that PTP-1B has a major role in modulating both insulin sensitivity and fuel metabolism, thereby establishing it as a potential therapeutic target in the treatment of type 2 diabetes and obesity.
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Affiliation(s)
- M Elchebly
- Department of Biochemistry, McGill University, 3655 Drummond Street, Montreal, Quebec, Canada, H3G 1Y6
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