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Haeusler RA, McGraw TE, Accili D. Biochemical and cellular properties of insulin receptor signalling. Nat Rev Mol Cell Biol 2018; 19:31-44. [PMID: 28974775 PMCID: PMC5894887 DOI: 10.1038/nrm.2017.89] [Citation(s) in RCA: 409] [Impact Index Per Article: 68.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The mechanism of insulin action is a central theme in biology and medicine. In addition to the rather rare condition of insulin deficiency caused by autoimmune destruction of pancreatic β-cells, genetic and acquired abnormalities of insulin action underlie the far more common conditions of type 2 diabetes, obesity and insulin resistance. The latter predisposes to diseases ranging from hypertension to Alzheimer disease and cancer. Hence, understanding the biochemical and cellular properties of insulin receptor signalling is arguably a priority in biomedical research. In the past decade, major progress has led to the delineation of mechanisms of glucose transport, lipid synthesis, storage and mobilization. In addition to direct effects of insulin on signalling kinases and metabolic enzymes, the discovery of mechanisms of insulin-regulated gene transcription has led to a reassessment of the general principles of insulin action. These advances will accelerate the discovery of new treatment modalities for diabetes.
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Affiliation(s)
- Rebecca A Haeusler
- Columbia University College of Physicians and Surgeons, Department of Pathology and Cell Biology, New York, New York 10032, USA
| | - Timothy E McGraw
- Weill Cornell Medicine, Departments of Biochemistry and Cardiothoracic Surgery, New York, New York 10065, USA
| | - Domenico Accili
- Columbia University College of Physicians & Surgeons, Department of Medicine, New York, New York 10032, USA
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2
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Elong Edimo W, Schurmans S, Roger PP, Erneux C. SHIP2 signaling in normal and pathological situations: Its impact on cell proliferation. Adv Biol Regul 2014; 54:142-151. [PMID: 24091101 DOI: 10.1016/j.jbior.2013.09.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 09/03/2013] [Indexed: 06/02/2023]
Abstract
Phosphoinositide 5-phosphatases are critical enzymes in modulating the concentrations of PI(3,4,5)P3, PI(4,5)P2 and PI(3,5)P2. The SH2 domain containing inositol 5-phosphatases SHIP1 and SHIP2 belong to this family of enzymes that dephosphorylate the 5 position of PI(3,4,5)P3 to produce PI(3,4)P2. Data obtained in zebrafish and in mice have shown that SHIP2 is critical in development and growth. Exome sequencing identifies mutations in the coding region of SHIP2 as a cause of opsismodysplasia, a severe but rare chondrodysplasia in human. SHIP2 has been reported to have both protumorigenic and tumor suppressor function in human cancer very much depending on the cell model. This could be linked to the relative importance of PI(3,4)P2 (a product of SHIP2 phosphatase activity) which is also controlled by the PI 4-phosphatase and tumor suppressor INPP4B. In the glioblastoma cell line 1321 N1, that do not express PTEN, lowering SHIP2 expression has an impact on the levels of PI(3,4,5)P3, cell morphology and cell proliferation. It positively stimulates cell proliferation by decreasing the expression of key regulatory proteins of the cell cycle such as p27. Together the data point out to a role of SHIP2 in development in normal cells and at least in cell proliferation in some cancer derived cells.
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Affiliation(s)
- William's Elong Edimo
- Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, Campus Erasme, Bldg C, 808 Route de Lennik, 1070 Brussels, Belgium
| | - Stéphane Schurmans
- Laboratoire de Génétique fonctionnelle, GIGA-Research Centre, Secteur de Biochimie Métabolique, Département des Sciences Fonctionnelles (Faculté de Médecine vétérinaire), Université de Liège, 1 rue de l'Hôpital, 4000 Liège, Belgium; Walloon Excellence in Lifesciences and Biotechnology (WELBIO), Belgium
| | - Pierre P Roger
- Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, Campus Erasme, Bldg C, 808 Route de Lennik, 1070 Brussels, Belgium; Walloon Excellence in Lifesciences and Biotechnology (WELBIO), Belgium
| | - Christophe Erneux
- Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, Campus Erasme, Bldg C, 808 Route de Lennik, 1070 Brussels, Belgium.
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3
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Condé C, Gloire G, Piette J. Enzymatic and non-enzymatic activities of SHIP-1 in signal transduction and cancer. Biochem Pharmacol 2011; 82:1320-34. [PMID: 21672530 DOI: 10.1016/j.bcp.2011.05.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 05/27/2011] [Indexed: 12/29/2022]
Abstract
PI3K cascade is a central signaling pathway regulating cell proliferation, growth, differentiation, and survival. Tight regulation of the PI3K signaling pathway is necessary to avoid aberrant cell proliferation and cancer development. Together with SHIP-1, the inositol phosphatases PTEN and SHIP-2 are the gatekeepers of this pathway. In this review, we will focus on SHIP-1 functions. Negative regulation of immune cell activation by SHIP-1 is well characterized. Besides its catalytic activity, SHIP-1 also displays non-enzymatic activity playing role in several immune pathways. Indeed, SHIP-1 exhibits several domains that mediate protein-protein interaction. This review emphasizes the negative regulation of immune cell activation by SHIP-1 that is mediated by its protein-protein interaction.
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Affiliation(s)
- Claude Condé
- Laboratory of Virology & Immunology, GIGA-Research B34, University of Liège, B-4000 Liège, Belgium
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4
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Liu E, Yuan JM. Dynamic sensitivity and control analyses of metabolic insulin signalling pathways. IET Syst Biol 2010; 4:64-81. [PMID: 20001093 DOI: 10.1049/iet-syb.2008.0178] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- E Liu
- Drexel University, Department of Physics, Philadelphia, PA 19104-2875, USA
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5
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Xie J, Onnockx S, Vandenbroere I, Degraef C, Erneux C, Pirson I. The docking properties of SHIP2 influence both JIP1 tyrosine phosphorylation and JNK activity. Cell Signal 2008; 20:1432-41. [PMID: 18486448 DOI: 10.1016/j.cellsig.2008.03.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 03/14/2008] [Accepted: 03/19/2008] [Indexed: 12/30/2022]
Abstract
SHIP2 (SH2-containing inositol polyphosphate 5-phosphatase 2) is an ubiquitously expressed phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P(3)) 5-phosphatase which contains various motifs susceptible to mediate protein-protein interaction. In cell models, evidence has been provided that SHIP2 plays a role in insulin and growth factor signaling, cytoskeletal organization, cell adhesion and migration. Herein we describe the c-Jun NH2-terminal kinase (JNK)-interacting protein 1 (JIP1) as a new protein partner of SHIP2. The interaction between SHIP2 and JIP1 was confirmed in both overexpression systems and native cells. Without modifying the association of JIP1 with the MAPKs in the scaffold complex and with no apparent change of Akt phosphorylation, SHIP2 positively modulated the MLK3/JIP1-mediated JNK1 activation. Moreover, SHIP2 positively regulated the tyrosine phosphorylation of JIP1. This up-regulation was prevented by inhibitors of the Src family and Abl kinases, PP2 and Glivec. The effects of SHIP2 on JNK activity and JIP1 tyrosine phosphorylation were independent of the SHIP2 phosphoinositide 5-phosphatase activity, as similar results were obtained when using a SHIP2 catalytic inactive mutant instead of wild-type SHIP2. Together, these data suggest that by its docking properties, SHIP2 can modulate JIP1-mediated JNK pathway signaling.
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Affiliation(s)
- Jingwei Xie
- Institute of Interdisciplinary Research (IRIBHM), School of Medicine, Free University of Brussels, Campus Erasme, Building C, Route de Lennik 808, B-1070 Brussels, Belgium
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6
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Onnockx S, De Schutter J, Blockmans M, Xie J, Jacobs C, Vanderwinden JM, Erneux C, Pirson I. The association between the SH2-containing inositol polyphosphate 5-Phosphatase 2 (SHIP2) and the adaptor protein APS has an impact on biochemical properties of both partners. J Cell Physiol 2007; 214:260-72. [PMID: 17620296 DOI: 10.1002/jcp.21193] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SHIP2 (SH2-containing inositol polyphosphate 5-phosphatase 2) is a phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P(3)) 5-phosphatase containing various motifs susceptible to mediate protein-protein interaction. In cell models, SHIP2 negatively regulates insulin signalling through its catalytic PtdIns(3,4,5)P(3) 5-phosphatase activity. We have previously reported that SHIP2 interacts with the c-Cbl associated protein (CAP) and c-Cbl, proteins implicated in the insulin cellular response regulating the small G protein TC10. The first steps of the TC10 pathway are the recruitment and tyrosine phosphorylation by the insulin receptor of the adaptor protein with Pleckstrin Homology and Src Homology 2 domains (APS). Herein, we show that SHIP2 can directly interact with APS in 3T3-L1 adipocytes and in transfected CHO-IR cells (Chinese hamster ovary cells stably transfected with the insulin receptor). Upon insulin stimulation, APS and SHIP2 are recruited to cell membranes as seen by immunofluorescence studies, which is consistent with their interaction. We also observed that SHIP2 negatively regulates APS insulin-induced tyrosine phosphorylation and consequently inhibits APS association with c-Cbl. APS, which specifically interacts with SHIP2, but not PTEN, in turn, increases the PtdIns(3,4,5)P(3) 5-phosphatase activity of SHIP2 in an inositol phosphatase assay. Co-transfection of SHIP2 and APS in CHO-IR cells further increases the inhibitory effect of SHIP2 on Akt insulin-induced phosphorylation. Therefore, the interaction between APS and SHIP2 provides to both proteins potential negative regulatory mechanisms to act on the insulin cascade.
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Affiliation(s)
- Sheela Onnockx
- Institute of Interdisciplinary Research (IRIBHM), Brussels, Belgium
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7
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Zhang J, Liu Z, Rasschaert J, Blero D, Deneubourg L, Schurmans S, Erneux C, Pesesse X. SHIP2 controls PtdIns(3,4,5)P3 levels and PKB activity in response to oxidative stress. Cell Signal 2007; 19:2194-200. [PMID: 17643961 DOI: 10.1016/j.cellsig.2007.06.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Accepted: 06/21/2007] [Indexed: 01/01/2023]
Abstract
Reactive oxygen species (ROS) are known to be involved in redox signalling pathways that may contribute to normal cell function as well as disease progression. The tumour suppressor PTEN and the inositol 5-phosphatase SHIP2 are critical enzymes in the control of PtdIns(3,4,5)P(3) level. It has been reported that oxidants, including those produced in cells such as macrophages, can activate downstream signalling via the inactivation of PTEN. The present study evaluates the potential impact of SHIP2 on phosphoinositides in cells exposed to sodium peroxide. We used a model of SHIP2 deficient mouse embryonic fibroblasts (MEFs) stimulated by H(2)O(2): at 15 min, PtdIns(3,4,5)P(3) was markedly increased in SHIP2 -/- cells as compared to +/+ cells. In contrast, no significant increase in PtdIns(3,4)P(2) could be detected at 15 or 120 min incubation of the cells with H(2)O(2) (0.6 mM). PKB activity was also upregulated in SHIP2 -/- cells as compared to +/+ cells in response to H(2)O(2). SHIP2 add back experiments in SHIP2 -/- cells confirm its critical role as a lipid phosphatase in the control of PtdIns(3,4,5)P(3) level in response to H(2)O(2). We conclude that SHIP2 lipid phosphatase activity plays an important role in the metabolism PtdIns(3,4,5)P(3) which is demonstrated in oxygen stressed cells.
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Affiliation(s)
- Jing Zhang
- Institut de Recherche Interdisciplinaire (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 808 Route de Lennik, 1070 Brussels, Belgium
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8
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Blero D, Payrastre B, Schurmans S, Erneux C. Phosphoinositide phosphatases in a network of signalling reactions. Pflugers Arch 2007; 455:31-44. [PMID: 17605038 DOI: 10.1007/s00424-007-0304-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 05/18/2007] [Accepted: 05/29/2007] [Indexed: 12/18/2022]
Abstract
Phosphoinositide phosphatases dephosphorylate the three positions (D-3, 4 and 5) of the inositol ring of the poly-phosphoinositides. They belong to different families of enzymes. The PtdIns(3,4)P(2) 4-phosphatase family, the tumour suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN), SAC1 domain phosphatases and myotubularins belong to the tyrosine protein phosphatases superfamily. They share the presence of a conserved cysteine residue in the consensus CX(5)RT/S. Another family consists of the inositol polyphosphate 5-phosphatase isoenzymes. The importance of these phosphoinositide phosphatases in cell regulation is illustrated by multiple examples of their implications in human diseases such as Lowe syndrome, X-linked myotubular myopathy, cancer, diabetes or bacterial infection.
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Affiliation(s)
- Daniel Blero
- Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, Campus Erasme, Bldg C, 808 Route de Lennik, 1070, Brussels, Belgium
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9
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Huard C, Martinez RV, Ross C, Johnson JW, Zhong W, Hill AA, Kim R, Paulsen JE, Shih HH. Transcriptional profiling of C2C12 myotubes in response to SHIP2 depletion and insulin stimulation. Genomics 2007; 89:270-9. [PMID: 17123777 DOI: 10.1016/j.ygeno.2006.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 10/18/2006] [Accepted: 10/18/2006] [Indexed: 11/23/2022]
Abstract
Phosphoinositide lipids generated at the cell membrane are a key component of a variety of signaling pathways. Among several inositol phosphatases that regulate the availability of signaling phosphoinositide lipids, the type II SH2-domain-containing inositol 5-phosphatase (SHIP2; approved gene symbol Inppl1) is believed to have multiple functions, including the regulation of insulin signaling and cytoskeletal functions. To understand the function of SHIP2 in C2C12 muscle cells, we depleted SHIP2 through the use of RNA interference and analyzed the global effect of SHIP2 depletion on gene expression using Affymetrix microarrays containing approximately 45,000 mouse probe sets. Expression of SHIP2-targeting small-hairpin RNA in differentiated C2C12 muscle cells led to >80% decrease in SHIP2 mRNA and 60-80% decrease in SHIP2 protein, which resulted in significant gene expression changes linked to cytoskeletal functions, including altered expression of adducin-alpha, pallidin, stathmin-like-2, and synaptojanin-2 binding protein. Insulin treatment of C2C12 muscle cells caused transcriptional changes associated with known signaling pathways. However, SHIP2 depletion had no discernible effect on insulin-regulated gene expression. Taken together, our results suggest that SHIP2 is involved in the regulation of cytoskeletal functions, but a large reduction of SHIP2 in C2C12 muscle cells is not sufficient to affect insulin-mediated gene expression.
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Affiliation(s)
- Christine Huard
- Biological Technologies, Wyeth Research, 87 Cambridge Park Drive, Cambridge, MA 02140, USA
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10
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Sasaoka T, Wada T, Tsuneki H. Lipid phosphatases as a possible therapeutic target in cases of type 2 diabetes and obesity. Pharmacol Ther 2006; 112:799-809. [PMID: 16842857 DOI: 10.1016/j.pharmthera.2006.06.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Accepted: 06/05/2006] [Indexed: 11/26/2022]
Abstract
Phosphatidyl inositol 3-kinase (PI3-kinase) functions as a lipid kinase to produce PI(3,4,5)P(3) from PI(4,5)P(2) in vivo. PI(3,4,5)P(3) is crucial as a lipid second messenger in various metabolic effects of insulin. Lipid phosphatases, src homology 2 domain containing inositol 5'-phosphatase 2 (SHIP2) and skeletal muscle and kidney-enriched inositol phosphatase (SKIP) hydrolyze PI(3,4,5)P(3) to PI(3,4)P(2) and phosphatase and tensin homolog deleted on chromosome ten (PTEN) hydrolyzes PI(3,4,5)P(3) to PI(4,5)P(2). SHIP2 negatively regulates insulin signaling relatively specifically via its 5'-phosphatase activity. Targeted disruption of the SHIP2 gene in mice resulted in increased insulin sensitivity and conferred protection from obesity induced by a high-fat diet. Polymorphisms in the human SHIP2 gene are associated, at least in part, with the insulin resistance of type 2 diabetes. Importantly, inhibition of endogenous SHIP2 through the liver-specific expression of a dominant-negative SHIP2 improves glucose metabolism and insulin resistance in diabetic db/db mice. Overexpression of PTEN and SKIP also inhibited insulin-induced phosphorylation of Akt and the uptake of glucose in cultured cells. Although a homozygous disruption of the PTEN gene in mice results in embryonic lethality, either skeletal muscle or adipose tissue-specific disruption of PTEN ameliorated glucose metabolism without formation of tumors in animal models of diabetes. The role of SKIP in glucose metabolism remains to be further clarified in vivo. Taken together, inhibition of endogenous SHIP2 in the whole body appears to be effective at improving the insulin resistance associated with type 2 diabetes and/or obesity. Inhibition of PTEN in the tissues specifically targeted, including skeletal muscle and fat, may result in an amelioration of insulin resistance in type 2 diabetes, although caution against the formation of tumors is needed.
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Affiliation(s)
- Toshiyasu Sasaoka
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
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11
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Lazar DF, Saltiel AR. Lipid phosphatases as drug discovery targets for type 2 diabetes. Nat Rev Drug Discov 2006; 5:333-42. [PMID: 16582877 DOI: 10.1038/nrd2007] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The soaring incidence of type 2 diabetes has created pressure for new pharmaceutical strategies to treat this devastating disease. With much of the focus on overcoming insulin resistance, investigation has focused on finding ways to restore activation of the phosphatidylinositol 3'-kinase pathway, which is diminished in many patients with type 2 diabetes. Here we review the evidence that lipid phosphatases, specifically PTEN and SHIP2, attenuate this important insulin signalling pathway. Both in vivo and in vitro studies indicate their role in regulating whole-body energy metabolism, and possibly weight gain as well. The promise and challenges presented by this new class of drug discovery targets will also be discussed.
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Affiliation(s)
- Dan F Lazar
- Eli Lilly and Co., Endocrine Division, Lilly Research Laboratories, Indianapolis, Indianapolis 46285, USA.
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12
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Dyson JM, Kong AM, Wiradjaja F, Astle MV, Gurung R, Mitchell CA. The SH2 domain containing inositol polyphosphate 5-phosphatase-2: SHIP2. Int J Biochem Cell Biol 2005; 37:2260-5. [PMID: 15964236 DOI: 10.1016/j.biocel.2005.05.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2005] [Revised: 05/04/2005] [Accepted: 05/04/2005] [Indexed: 11/24/2022]
Abstract
Phosphoinositides are membrane-bound signaling molecules that recruit, activate and localize target effectors to intracellular membranes regulating apoptosis, cell proliferation, insulin signaling and membrane trafficking. The SH2 domain containing inositol polyphosphate 5-phosphatase-2 (SHIP2) hydrolyzes phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3) generating phosphatidylinositol 3,4-bisphosphate (PtdIns(3,4)P2). Overexpression of SHIP2 inhibits insulin-stimulated phosphoinositide 3-kinase (PI3K) dependent signaling events. Analysis of diabetic human subjects has revealed an association between SHIP2 gene polymorphisms and type 2 diabetes mellitus. Genetic ablation of SHIP2 in mice has generated conflicting results. SHIP2 knockout mice were originally reported to show lethal neonatal hypoglycemia resulting from insulin hypersensitivity, but in addition to inactivating the SHIP2 gene, the Phox2a gene was also inadvertently deleted. Another SHIP2 knockout mouse has now been generated which inactivates the SHIP2 gene but leaves Phox2a intact. These animals show normal insulin and glucose tolerance but are highly resistant to weight gain on high fat diets, exhibiting an obesity-resistant phenotype. Therefore, SHIP2 remains a significant therapeutic target for the treatment of both obesity and type 2 diabetes.
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Affiliation(s)
- Jennifer M Dyson
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Vic. 3800, Australia
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13
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Blero D, Zhang J, Pesesse X, Payrastre B, Dumont JE, Schurmans S, Erneux C. Phosphatidylinositol 3,4,5-trisphosphate modulation in SHIP2-deficient mouse embryonic fibroblasts. FEBS J 2005; 272:2512-22. [PMID: 15885100 DOI: 10.1111/j.1742-4658.2005.04672.x] [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] [Indexed: 01/08/2023]
Abstract
SHIP2, the ubiquitous SH2 domain containing inositol 5-phosphatase, includes a series of protein interacting domains and has the ability to dephosphorylate phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P(3)]in vitro. The present study, which was undertaken to evaluate the impact of SHIP2 on PtdIns(3,4,5)P(3) levels, was performed in a mouse embryonic fibroblast (MEF) model using SHIP2 deficient (-/-) MEF cells derived from knockout mice. PtdIns(3,4,5)P(3) was upregulated in serum stimulated -/- MEF cells as compared to +/+ MEF cells. Although the absence of SHIP2 had no effect on basal PtdIns(3,4,5)P(3) levels, we show here that this lipid was significantly upregulated in SHIP2 -/- cells but only after short-term (i.e. 5-10 min) incubation with serum. The difference in PtdIns(3,4,5)P(3) levels in heterozygous fibroblast cells was intermediate between the +/+ and the -/- cells. In our model, insulin-like growth factor-1 stimulation did not show this upregulation. Serum stimulated phosphoinositide 3-kinase (PI 3-kinase) activity appeared to be comparable between +/+ and -/- cells. Moreover, protein kinase B, but not mitogen activated protein kinase activity, was also potentiated in SHIP2 deficient cells stimulated by serum. The upregulation of protein kinase B activity in serum stimulated cells was totally reversed in the presence of the PI 3-kinase inhibitor LY-294002, in both +/+ and -/- cells. Altogether, these data establish a link between SHIP2 and the acute control of PtdIns(3,4,5)P(3) levels in intact cells.
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MESH Headings
- Animals
- Cells, Cultured
- Culture Media/chemistry
- Embryo, Mammalian/anatomy & histology
- Embryo, Mammalian/physiology
- Fibroblasts/cytology
- Fibroblasts/physiology
- Growth Substances/metabolism
- Inositol Polyphosphate 5-Phosphatases
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- PTEN Phosphohydrolase
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphatidylinositol Phosphates/metabolism
- Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
- Phosphoric Monoester Hydrolases/genetics
- Phosphoric Monoester Hydrolases/metabolism
- Protein Tyrosine Phosphatase, Non-Receptor Type 1
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases/metabolism
- Receptor, IGF Type 1/genetics
- Receptor, IGF Type 1/metabolism
- Tumor Suppressor Proteins/genetics
- Tumor Suppressor Proteins/metabolism
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Affiliation(s)
- Daniel Blero
- Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, Belgium
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15
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Prasad NK, Decker SJ. SH2-containing 5'-inositol phosphatase, SHIP2, regulates cytoskeleton organization and ligand-dependent down-regulation of the epidermal growth factor receptor. J Biol Chem 2005; 280:13129-36. [PMID: 15668240 DOI: 10.1074/jbc.m410289200] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Phosphoinositide lipid second messengers are integral components of signaling pathways mediated by insulin, growth factors, and integrins. SHIP2 dephosphorylates phosphatidylinositol 3,4,5-trisphosphate generated by the activated phosphatidylinositol 3'-kinase. SHIP2 down-regulates insulin signaling and is present at higher levels in diabetes and obesity. SHIP2 associates with p130Cas and filamin, regulators of cell adhesion/migration and cytoskeleton, influencing cell adhesion/spreading. Type I collagen specifically induces Src-mediated tyrosine phosphorylation of SHIP2. To better understand SHIP2 function, we employed RNA interference (RNAi) approach to silence the expression of the endogenous SHIP2 in HeLa cells. Suppression of SHIP2 levels caused severe F-actin deformities characterized by weak cortical actin and peripheral actin spikes. SHIP2 RNAi cells displayed cell-spreading defects involving a notable absence of focal contact structures and the formation of multiple slender membrane protrusions capped by actin spikes. Furthermore, decreased SHIP2 levels altered distribution of early endocytic antigen 1 (EEA1)-positive endocytic vesicles and of vesicles containing internalized epidermal growth factor (EGF) and transferrin. EGF treatment of SHIP2 RNAi cells led to the following: enhanced EGF receptor (EGFR) degradation; increased EGFR ubiquitination; and increased association of EGFR with c-Cbl ubiquitin ligase. Taken together, these experiments demonstrate that SHIP2 functions in the maintenance and dynamic remodeling of actin structures as well as in endocytosis, having a major impact on ligand-induced EGFR internalization and degradation. Accordingly, we suggest that, in HeLa cells, SHIP2 plays a distinct role in signaling pathways mediated by integrins and growth factor receptors.
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Affiliation(s)
- Nagendra K Prasad
- Department of Basic Medical Sciences and Purdue Cancer Center, Purdue University, West Lafayette, Indiana 47907, USA.
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16
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Sleeman MW, Wortley KE, Lai KMV, Gowen LC, Kintner J, Kline WO, Garcia K, Stitt TN, Yancopoulos GD, Wiegand SJ, Glass DJ. Absence of the lipid phosphatase SHIP2 confers resistance to dietary obesity. Nat Med 2005; 11:199-205. [PMID: 15654325 DOI: 10.1038/nm1178] [Citation(s) in RCA: 199] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Accepted: 12/22/2004] [Indexed: 12/21/2022]
Abstract
Genetic ablation of Inppl1, which encodes SHIP2 (SH2-domain containing inositol 5-phosphatase 2), was previously reported to induce severe insulin sensitivity, leading to early postnatal death. In the previous study, the targeting construct left the first eighteen exons encoding Inppl1 intact, generating a Inppl1(EX19-28-/-) mouse, and apparently also deleted a second gene, Phox2a. We report a new SHIP2 knockout (Inppl1(-/-)) targeted to the translation-initiating ATG, which is null for Inppl1 mRNA and protein. Inppl1(-/-) mice are viable, have normal glucose and insulin levels, and normal insulin and glucose tolerances. The Inppl1(-/-) mice are, however, highly resistant to weight gain when placed on a high-fat diet. These results suggest that inhibition of SHIP2 would be useful in the effort to ameliorate diet-induced obesity, but call into question a dominant role of SHIP2 in modulating glucose homeostasis.
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Affiliation(s)
- Mark W Sleeman
- Regeneron Pharmaceuticals, Inc. 777 Old Saw Mill River Road, Tarrytown, New York 10591-6707, USA
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