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Kim SS, Park SH, Lee JR, Jung JS, Suh HW. The activation of α 2-adrenergic receptor in the spinal cord lowers sepsis-induced mortality. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 21:495-507. [PMID: 28883754 PMCID: PMC5587600 DOI: 10.4196/kjpp.2017.21.5.495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 05/09/2017] [Accepted: 06/09/2017] [Indexed: 01/27/2023]
Abstract
The effect of clonidine administered intrathecally (i.t.) on the mortality and the blood glucose level induced by sepsis was examined in mice. To produce sepsis, the mixture of D-galactosamine (GaLN; 0.6 g/10 ml)/lipopolysaccharide (LPS; 27 µg/27 µl) was treated intraperitoneally (i.p.). The i.t. pretreatment with clonidine (5 µg/5 µl) increased the blood glucose level and attenuated mortality induced by sepsis in a dose-dependent manner. The i.t. post-treatment with clonidine up to 3 h caused an elevation of the blood glucose level and protected sepsis-induced mortality, whereas clonidine post-treated at 6, 9, or 12 h did not affect. The pre-treatment with oral D-glucose for 30 min prior to i.t. post-treatment (6 h) with clonidine did not rescue sepsis-induced mortality. In addition, i.t. pretreatment with pertussis toxin (PTX) reduced clonidine-induced protection against mortality and clonidine-induced hyperglycemia, suggesting that protective effect against sepsis-induced mortality seems to be mediated via activating PTX-sensitive G-proteins in the spinal cord. Moreover, pretreatment with clonidine attenuated the plasma tumor necrosis factor α (TNF-α) induced by sepsis. Clonidine administered i.t. or i.p. increased p-AMPKα1 and p-AMPKα2, but decreased p-Tyk2 and p-mTOR levels in both control and sepsis groups, suggesting that the up-regulations of p-AMPKα1 and p-AMPKα2, or down-regulations of p-mTOR and p-Tyk2 may play critical roles for the protective effect of clonidine against sepsis-induced mortality.
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Affiliation(s)
- Sung-Su Kim
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine Hallym University, Chuncheon 24252, Korea
| | - Soo-Hyun Park
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine Hallym University, Chuncheon 24252, Korea
| | - Jae-Ryung Lee
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine Hallym University, Chuncheon 24252, Korea
| | - Jun-Sub Jung
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine Hallym University, Chuncheon 24252, Korea
| | - Hong-Won Suh
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine Hallym University, Chuncheon 24252, Korea
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Suh HW, Sim YB, Park SH, Sharma N, Im HJ, Hong JS. Effect of pertussis toxin pretreated centrally on blood glucose level induced by stress. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2016; 20:467-76. [PMID: 27610033 PMCID: PMC5014993 DOI: 10.4196/kjpp.2016.20.5.467] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 04/23/2016] [Accepted: 05/11/2016] [Indexed: 01/08/2023]
Abstract
In the present study, we examined the effect of pertussis toxin (PTX) administered centrally in a variety of stress-induced blood glucose level. Mice were exposed to stress after the pretreatment of PTX (0.05 or 0.1 µg) i.c.v. or i.t. once for 6 days. Blood glucose level was measured at 0, 30, 60 and 120 min after stress stimulation. The blood glucose level was increased in all stress groups. The blood glucose level reached at maximum level after 30 min of stress stimulation and returned to a normal level after 2 h of stress stimulation in restraint stress, physical, and emotional stress groups. The blood glucose level induced by cold-water swimming stress was gradually increased up to 1 h and returned to the normal level. The intracerebroventricular (i.c.v.) or intrathecal (i.t.) pretreatment with PTX, a Gi inhibitor, alone produced a hypoglycemia and almost abolished the elevation of the blood level induced by stress stimulation. The central pretreatment with PTX caused a reduction of plasma insulin level, whereas plasma corticosterone level was further up-regulated in all stress models. Our results suggest that the hyperglycemia produced by physical stress, emotional stress, restraint stress, and the cold-water swimming stress appear to be mediated by activation of centrally located PTX-sensitive G proteins. The reduction of blood glucose level by PTX appears to due to the reduction of plasma insulin level. The reduction of blood glucose level by PTX was accompanied by the reduction of plasma insulin level. Plasma corticosterone level up-regulation by PTX in stress models may be due to a blood glucose homeostatic mechanism.
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Affiliation(s)
- Hong-Won Suh
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 24252, Korea
| | - Yun-Beom Sim
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 24252, Korea.; Adult Stem Cell Research Center in Kangstem Biotech, Seoul National University, Seoul 08826, Korea
| | - Soo-Hyun Park
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 24252, Korea
| | - Naveen Sharma
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 24252, Korea
| | - Hyun-Ju Im
- College of Physical Education, Kookmin University, Seoul 02707, Korea
| | - Jae-Seung Hong
- Department of Physical Education, College of Natural Science, Hallym University, Chuncheon 24252, Korea
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Lopez-Sanchez I, Ma GS, Pedram S, Kalogriopoulos N, Ghosh P. GIV/girdin binds exocyst subunit-Exo70 and regulates exocytosis of GLUT4 storage vesicles. Biochem Biophys Res Commun 2015; 468:287-93. [PMID: 26514725 DOI: 10.1016/j.bbrc.2015.10.111] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/21/2015] [Indexed: 10/22/2022]
Abstract
Insulin resistance (IR) is a metabolic disorder characterized by impaired glucose uptake in response to insulin. The current paradigm for insulin signaling centers upon the insulin receptor (InsR) and its substrate IRS1; the latter is believed to be the chief conduit for post-receptor signaling. We recently demonstrated that GIV, a Guanidine Exchange Factor (GEF) for the trimeric G protein, Gαi, is a major hierarchical conduit for the metabolic insulin response. By virtue of its ability to directly bind the InsR, IRS1 and PI3K, GIV enhances the InsR-IRS1-Akt-AS160 (RabGAP) signaling cascade and cellular glucose uptake via its GEF function. Phosphoinhibition of GIV-GEF by the fatty-acid/PKCθ pathway inhibits the cascade and impairs glucose uptake. Here we show that GIV directly and constitutively binds the exocyst complex subunit Exo-70 and also associates with GLUT4-storage vesicles (GSVs) exclusively upon insulin stimulation. Without GIV or its GEF function, membrane association of Exo-70 as well as exocytosis of GSVs in response to insulin are impaired. Thus, GIV is an essential component within the insulin signaling cascade that couples upstream signal transducers within the InsR and G-Protein signaling cascade to downstream vesicular trafficking events within the exocytic pathway. These findings suggest a role of GIV in coordinating key signaling and trafficking events of metabolic insulin response.
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Affiliation(s)
- Inmaculada Lopez-Sanchez
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Gary S Ma
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Shabnam Pedram
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Nicholas Kalogriopoulos
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Pradipta Ghosh
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA; Department of Cell and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA.
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Ma GS, Lopez-Sanchez I, Aznar N, Kalogriopoulos N, Pedram S, Midde K, Ciaraldi TP, Henry RR, Ghosh P. Activation of G proteins by GIV-GEF is a pivot point for insulin resistance and sensitivity. Mol Biol Cell 2015; 26:4209-23. [PMID: 26378251 PMCID: PMC4642855 DOI: 10.1091/mbc.e15-08-0553] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 09/11/2015] [Indexed: 11/11/2022] Open
Abstract
A long-held tenet in the field of diabetes is that the tipping point between insulin sensitivity and resistance resides at the level of insulin receptor/insulin receptor substrate–adaptor complexes. Here it is shown that activation of Gαi by GIV/Girdin is a decisive event within the metabolic insulin signaling cascade that reversibly orchestrates insulin sensitivity or resistance. Insulin resistance (IR) is a metabolic disorder characterized by impaired insulin signaling and cellular glucose uptake. The current paradigm for insulin signaling centers upon the insulin receptor (InsR) and its substrate IRS1; the latter is believed to be the sole conduit for postreceptor signaling. Here we challenge that paradigm and show that GIV/Girdin, a guanidine exchange factor (GEF) for the trimeric G protein Gαi, is another major hierarchical conduit for the metabolic insulin response. By virtue of its ability to directly bind InsR, IRS1, and phosphoinositide 3-kinase, GIV serves as a key hub in the immediate postreceptor level, which coordinately enhances the metabolic insulin response and glucose uptake in myotubes via its GEF function. Site-directed mutagenesis or phosphoinhibition of GIV-GEF by the fatty acid/protein kinase C-theta pathway triggers IR. Insulin sensitizers reverse phosphoinhibition of GIV and reinstate insulin sensitivity. We also provide evidence for such reversible regulation of GIV-GEF in skeletal muscles from patients with IR. Thus GIV is an essential upstream component that couples InsR to G-protein signaling to enhance the metabolic insulin response, and impairment of such coupling triggers IR. We also provide evidence that GIV-GEF serves as therapeutic target for exogenous manipulation of physiological insulin response and reversal of IR in skeletal muscles.
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Affiliation(s)
- Gary S Ma
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Inmaculada Lopez-Sanchez
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Nicolas Aznar
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Nicholas Kalogriopoulos
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Shabnam Pedram
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Krishna Midde
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
| | - Theodore P Ciaraldi
- Department of Veterans Affairs, VA San Diego Healthcare System, San Diego, CA 92161
| | - Robert R Henry
- Department of Veterans Affairs, VA San Diego Healthcare System, San Diego, CA 92161
| | - Pradipta Ghosh
- Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093 Department of Veterans Affairs, VA San Diego Healthcare System, San Diego, CA 92161 Department of Cell and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093
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Kim CH, Park SH, Sim YB, Sharma N, Kim SS, Lim SM, Jung JS, Suh HW. Effect of pertussis and cholera toxins administered supraspinally on CA3 hippocampal neuronal cell death and the blood glucose level induced by kainic acid in mice. Neurosci Res 2014; 89:31-6. [DOI: 10.1016/j.neures.2014.08.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 08/20/2014] [Accepted: 08/26/2014] [Indexed: 10/24/2022]
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Phillips SA, Ciaraldi TP, Oh DK, Savu MK, Henry RR. Adiponectin secretion and response to pioglitazone is depot dependent in cultured human adipose tissue. Am J Physiol Endocrinol Metab 2008; 295:E842-50. [PMID: 18664597 PMCID: PMC2575897 DOI: 10.1152/ajpendo.90359.2008] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The subcutaneous (S) and visceral (V) adipose tissue (AT) depots are increasingly recognized as distinct. To test the hypothesis that depot differences exist for adiponectin, fresh and cultured human VAT and SAT from obese type 2 diabetic (T2D) and obese nondiabetic (ND) subjects was examined to determine whether differences in adiponectin content and secretion occurred as a function of depot studied, diabetic status, and response to thiazolidinedione treatment. VAT and SAT were obtained by biopsy and AT explants cultured in defined media for 7 days. Protein expression was assessed by Western blot. Adiponectin content of conditioned medium was determined by radioimmunoassay. Diabetic status had no effect on adiponectin secretion over days 0-2 of culture. In ND SAT, secretion fell over days 2-4 but was sustained at greater levels vs. T2D SAT. In both ND and T2D VAT, adiponectin secretion was low, similar to T2D SAT. Over the 7-day culture period, cellular adiponectin increased in ND SAT and VAT; it remained unchanged in T2D SAT and VAT. Pioglitazone increased adiponectin secretion and content in all SAT. Pioglitazone failed to increase adiponectin secretion from either ND or T2D VAT and increased cellular content only in ND VAT. AT depot differences exist in the secretion of adiponectin and responsiveness to thiazolidinedione treatment. These data suggest that SAT, not VAT, appears to be the major contributor to increased circulating adiponectin levels in response to pioglitazone treatment.
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Affiliation(s)
- Susan A Phillips
- Veterans Affairs San Diego Healthcare System, La Jolla, California 92161, USA.
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Hawkes C, Amritraj A, Macdonald RG, Jhamandas JH, Kar S. Heterotrimeric G proteins and the single-transmembrane domain IGF-II/M6P receptor: functional interaction and relevance to cell signaling. Mol Neurobiol 2008; 35:329-45. [PMID: 17917122 DOI: 10.1007/s12035-007-0021-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 11/30/1999] [Accepted: 04/02/2007] [Indexed: 12/11/2022]
Abstract
The G protein-coupled receptor (GPCR) family represents the largest and most versatile group of cell surface receptors. Classical GPCR signaling constitutes ligand binding to a seven-transmembrane domain receptor, receptor interaction with a heterotrimeric G protein, and the subsequent activation or inhibition of downstream intracellular effectors to mediate a cellular response. However, recent reports on direct, receptor-independent G protein activation, G protein-independent signaling by GPCRs, and signaling of nonheptahelical receptors via trimeric G proteins have highlighted the intrinsic complexities of G protein signaling mechanisms. The insulin-like growth factor-II/mannose-6 phosphate (IGF-II/M6P) receptor is a single-transmembrane glycoprotein whose principal function is the intracellular transport of lysosomal enzymes. In addition, the receptor also mediates some biological effects in response to IGF-II binding in both neuronal and nonneuronal systems. Multidisciplinary efforts to elucidate the intracellular signaling pathways that underlie these effects have generated data to suggest that the IGF-II/M6P receptor might mediate transmembrane signaling via a G protein-coupled mechanism. The purpose of this review is to outline the characteristics of traditional and nontraditional GPCRs, to relate the IGF-II/M6P receptor's structure with its role in G protein-coupled signaling and to summarize evidence gathered over the years regarding the putative signaling of the IGF-II/M6P receptor mediated by a G protein.
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Affiliation(s)
- C Hawkes
- Department of Psychiatry, Centre for Alzheimer and Neurodegenerative Research, University of Alberta, Edmonton, AB, T6G 2B7, Canada
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Abstract
Receptor tyrosine kinases (RTKs) are a unique family of cell surface receptors, each containing a common intracellular domain that has tyrosine kinase activity. However, RTKs share many signaling molecules with another unique family of cell surface receptors, the seven-transmembrane receptors (7TMRs), and these receptor families can activate similar signaling cascades. In this review of RTK signaling, we describe the role of cross talk between RTKs and 7TMRs, focusing specifically on the role played in this process by beta-arrestins and by G proteins.
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Affiliation(s)
- Christopher J Hupfeld
- Department of Medicine, Division of Endocrinology and Metabolism, University of California San Diego, La Jolla, California 92093, USA.
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Abstract
Heterotrimeric G proteins are key players in transmembrane signaling by coupling a huge variety of receptors to channel proteins, enzymes, and other effector molecules. Multiple subforms of G proteins together with receptors, effectors, and various regulatory proteins represent the components of a highly versatile signal transduction system. G protein-mediated signaling is employed by virtually all cells in the mammalian organism and is centrally involved in diverse physiological functions such as perception of sensory information, modulation of synaptic transmission, hormone release and actions, regulation of cell contraction and migration, or cell growth and differentiation. In this review, some of the functions of heterotrimeric G proteins in defined cells and tissues are described.
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Affiliation(s)
- Nina Wettschureck
- Institute of Pharmacology, University of Heidelberg, Im Neuenheimer Feld 366, D-69120 Heidelberg, Germany
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Patel TB. Single Transmembrane Spanning Heterotrimeric G Protein-Coupled Receptors and Their Signaling Cascades. Pharmacol Rev 2004; 56:371-85. [PMID: 15317909 DOI: 10.1124/pr.56.3.4] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heptahelical of serpentine receptors such as the adrenergic receptors are well known to mediate their actions via heterotrimeric GTP-binding proteins. Likewise, receptors that traverse the cell membrane once have been shown to mediate their biological actions by activating several different mechanisms including stimulation of their intrinsic tyrosine kinase activities or the kinase activities of other proteins. Some of these single transmembrane receptors have an intrinsic guanylyl cyclase activity and can stimulate the cyclic GMP second messenger system; however, over the last few years, several studies have shown the involvement of heterotrimeric GTP-binding proteins in mediating signals that eventually culminate in the biological actions of single transmembrane spanning receptors and proteins. These receptors include the receptor tyrosine kinases that mediate the actions of growth factors such as epidermal growth factor, insulin, insulin-like growth factor as well as receptors for atrial natiuretic hormone or the zona pellucida protein (ZP3) and integrins. In this review, the significance of the coupling of the single transmembrane spanning receptors to G proteins has been highlighted by providing several examples of the concept that signaling via these receptors may involve the activation of multiple signaling cascades.
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Affiliation(s)
- Tarun B Patel
- Department of Pharmacology and Experimental Therapeutics, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60513, USA.
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Russ M, Reinauer H, Eckel J. Regulation of cardiac insulin receptor function by guanosine nucleotides. FEBS Lett 2001. [DOI: 10.1016/0014-5793(92)81464-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Russ M, Reinauer H, Eckel J. Regulation of cardiac insulin receptor function by guanosine nucleotides. FEBS Lett 2001. [DOI: 10.1016/0014-5793(93)81518-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Yu S, Castle A, Chen M, Lee R, Takeda K, Weinstein LS. Increased insulin sensitivity in Gsalpha knockout mice. J Biol Chem 2001; 276:19994-8. [PMID: 11274197 DOI: 10.1074/jbc.m010313200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The stimulatory guanine nucleotide-binding protein (G(s)) is required for hormone-stimulated cAMP generation. Gnas, the gene encoding the G(s) alpha-subunit, is imprinted, and targeted disruption of this gene in mice leads to distinct phenotypes in heterozygotes depending on whether the maternal (m-/+) or paternal (+/p-) allele is mutated. Notably, m-/+ mice become obese, whereas +/p- mice are thinner than normal. In this study we show that despite these opposite changes in energy metabolism, both m-/+ and +/p- mice have greater sensitivity to insulin, with low to normal fasting glucose levels, low fasting insulin levels, improved glucose tolerance, and exaggerated hypoglycemic response to administered insulin. The combination of increased insulin sensitivity with obesity in m-/+ mice is unusual, because obesity is typically associated with insulin resistance. In skeletal muscles isolated from both m-/+ and +/p- mice, the basal rate of 2-deoxyglucose uptake was normal, whereas the rate of 2-deoxyglucose uptake in response to maximal insulin stimulation was significantly increased. The similar changes in muscle sensitivity to insulin in m-/+ and +/p- mice may reflect the fact that muscle G(s)alpha expression is reduced by approximately 50% in both groups of mice. GLUT4 expression is unaffected in muscles from +/p- mice. Increased responsiveness to insulin is therefore the result of altered insulin signaling and/or GLUT4 translocation. This is the first direct demonstration in a genetically altered in vivo model that G(s)-coupled pathways negatively regulate insulin signaling.
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Affiliation(s)
- S Yu
- Metabolic Diseases Branch and Diabetes Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
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O'Neill LA. Towards an understanding of the signal transduction pathways for interleukin 1. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1266:31-44. [PMID: 7718619 DOI: 10.1016/0167-4889(94)00217-3] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- L A O'Neill
- Department of Biochemistry and Biotechnology Institute, Trinity College, University of Dublin, Ireland
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Russ M, Wichelhaus A, Uphues I, Kolter T, Eckel J. Photoaffinity labelling of cardiac membrane GTP-binding proteins in response to insulin. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 219:325-30. [PMID: 8306999 DOI: 10.1111/j.1432-1033.1994.tb19944.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Plasma membranes from rat cardiac ventricular tissue and insulin receptors partially purified by wheat-germ-agglutinin chromatography were subjected to direct photoaffinity labelling with [alpha-32P]GTP in order to elucidate the presence of insulin-receptor-coupled GTP-binding proteins. In plasma membranes three proteins have been identified that exhibit an enhanced photolabelling with the nucleotide in response to insulin. The apparent molecular masses of these proteins were found to be 56, 60 and 74 kDa. Photolabelling of partially purified insulin receptors showed the copurification of the 60-kDa species, whereas the 56-kDa and 74-kDa proteins could not be detected. Furthermore, the 60-kDa G-protein was found to be specifically co-immunoprecipitated with the insulin receptor. Incubation of insulin receptors with insulin increased the labelling of the 60-kDa band to 205 +/- 27% (n = 5) of control. Immuno- and ligand-blotting experiments revealed the additional presence of a 39-kDa G(o)-like protein and two G-proteins with molecular masses of 24 and 26 kDa in the receptor preparation. Under basal conditions the insulin receptor and the 60-kDa G-protein exhibited an apparent inverse distribution between plasma and microsomal membranes with the G-protein being extensively labelled in the microsomal fraction. In conclusion, our data show that, in its native environment, the cardiac insulin receptor couples to at least three GTP-binding proteins. Out of these, a 60-kDa species of microsomal origin, copurifies with the insulin receptor. It is suggested that this G-protein is associated with the insulin receptor and may be involved in insulin receptor signalling in target cells.
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Affiliation(s)
- M Russ
- Laboratory of Molecular Cardiology, Diabetes Research Institute, Düsseldorf, Germany
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Okamoto T, Okamoto T, Murayama Y, Hayashi Y, Ogata E, Nishimoto I. GTP-binding protein-activator sequences in the insulin receptor. FEBS Lett 1993; 334:143-8. [PMID: 8224218 DOI: 10.1016/0014-5793(93)81700-a] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Some functions of the insulin receptor (insR) are assumed to be mediated by pertussis toxin-sensitive Gi/G(o) proteins. Here we have located G-protein-activator domains in the cytoplasmic region of the human insR. We searched the sequence of insR and found three candidate regions at residues 1039-1061, 1147-1168 and 1325-1345, referred to as ISRP1, ISRP2 and ISRP3, respectively. Among them, the Gi/G(o)-activating function was observed only in peptide ISRP3. ISRP1 specifically activated Gs, whereas ISRP2 had no effect on G proteins. ISRP2 and ISRP3 contained five of six autophosphorylated tyrosine residues in insR. After tyrosine phosphorylation, ISRP2 showed specific Gi-activating function, and ISRP3 potentiated its ability and became capable of activating G proteins generally. This is the first study that specifies G-protein-activator domains in insR and describes their modification by autophosphorylation.
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Affiliation(s)
- T Okamoto
- Department of Medicine, Harvard Medical School, Charlestown, MA 02129
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Ravindra R, Caro JF. Insulin stimulates GDP release from G proteins in the rat and human liver plasma membranes. J Cell Biochem 1993; 53:181-9. [PMID: 8263034 DOI: 10.1002/jcb.240530302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Plasma membranes (1-2 mg protein) prepared from the livers of adult male rats and human organ donors were incubated with 0.6 microM [alpha-32P] guanosine triphosphate (GTP) in an adenosine triphosphate (ATP)-regenerating buffer at 37 degrees C for 1 h; during this incubation, the [32P]GTP is hydrolyzed and the nucleotide that is predominantly bound to the membranes is [32P] guanosine diphosphate (GDP). [32P]GDP release from the liver membranes was proportional to the protein concentration and increased as a function of time. At 5 mM, Ca2+, Mg2+, Mn2+, and Zn2+ maximally inhibited GDP release by 80-90%, whereas, 5 mM Cu2+ maximally stimulated the reaction by 100%. Therefore, cations were not included in the buffer used in the GDP release step. One microM Gpp(NH)p (5'-guanylylimidodiphosphate), a nonhydrolyzable analog of GTP, maximally stimulated [32P]GDP release in the liver membranes by up to 30%. Although 10 nM Gpp(NH)p had no effect on GDP release, it appeared to stabilize the hormonal effect by blocking further GDP/GTP exchange. In the rat membranes, 1-100 nM glucagon (used as a positive control) stimulated [32P]GDP release by about 17% (P < .05); similarly, 0.1-100 nM insulin stimulated [32P]GDP release by 10-13% (P < .05). In the human membranes, 10 pM to 100 nM insulin stimulated [32P]GDP release by 7-10%. In the rat membranes, 10 nM insulin stimulated [32P]GDP release by 17 and 24% at 2 and 4 min, respectively (P < .05); in the human membranes, 10 nM insulin stimulated [32P]GDP release by about 9% at 2 and 4 min.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R Ravindra
- Department of Cell Biology, UMDNJ-School of Osteopathic Medicine, Stratford 08084
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Jo H, Radding W, Anantharamaiah GM, McDonald JM. An insulin receptor peptide (1135-1156) stimulates guanosine 5'-[gamma-thio]triphosphate binding to the 67 kDa G-protein associated with the insulin receptor. Biochem J 1993; 294 ( Pt 1):19-24. [PMID: 8363571 PMCID: PMC1134559 DOI: 10.1042/bj2940019] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Peptides representing two putative G-protein-binding motifs (GPBP1 and GPBP2) derived from insulin-receptor sequences were tested for their ability to stimulate guanosine 5'-[gamma-thio]-triphosphate (GTP[S]; 'GTP gamma S') binding to a preparation containing the 41 and 67 kDa G-proteins that are associated with the insulin receptor [Jo, Cha, Davis and McDonald (1992) Endocrinology (Baltimore) 131, 2855-2861]. GPBP2 (residues 1135-1156) specifically stimulated GTP[S] binding, whereas GPBP1 (1319-1333) did not. Substitution of Arg-1152 with Gln in GPBP2 corresponding to a mutation site in insulin-resistant patients [Cocozza, Porcellini, Riccardi, Monticelli, Condorelli, Ferrera, Pianese, Miele, Capaldo, Beguinot and Varrone (1992) Diabetes 41, 521-526] attenuated the stimulatory potency of GPBP2. Size-exclusion chromatography and studies with purified 67 kDa G-protein revealed that GPBP2 stimulated GTP[S] binding only to the 67 kDa G-protein. These studies provide evidence for a potential regulatory site for G-protein interaction with the insulin receptor in the tyrosine kinase domain.
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Affiliation(s)
- H Jo
- Department of Pathology, University of Alabama, Birmingham 35294
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20
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Wellner M, Mueckler MM, Keller K. GTP analogs suppress uptake but not transport of D-glucose analogs in Glut1 glucose transporter-expressing Xenopus oocytes. FEBS Lett 1993; 327:95-8. [PMID: 8335101 DOI: 10.1016/0014-5793(93)81047-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A Xenopus oocyte expression-co-injection system was used to study the influence of guanine nucleotides on D-glucose uptake. GTP analogs like GTP gamma S and GppNHp had no effect on 3-O-methylglucose transport determined by zero-trans uptake or equilibrium exchange, but suppressed 2-deoxyglucose uptake into Glut1 glucose transporter-expressing oocytes by up to 86%. Both GTP analogs showed concentration dependence of their effectiveness, with GTP gamma S being more potent than GppNHp. No statistically significant differences were observed between groups of oocytes co-injected with water or GDP beta S (250 and 500 microM intracellular concentration). Glut1 transporter expression in plasma membrane was not different between water or GTP gamma S-co-injected oocytes. Thus, inhibition of hexokinase catalytic activity is the most likely causative factor for down-regulation of 2-deoxyglucose uptake.
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Affiliation(s)
- M Wellner
- Institut für Pharmakologie, Freien Universität Berlin, Germany
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21
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Kahn CR, White MF, Shoelson SE, Backer JM, Araki E, Cheatham B, Csermely P, Folli F, Goldstein BJ, Huertas P. The insulin receptor and its substrate: molecular determinants of early events in insulin action. RECENT PROGRESS IN HORMONE RESEARCH 1993; 48:291-339. [PMID: 7680139 DOI: 10.1016/b978-0-12-571148-7.50015-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- C R Kahn
- Joslin Diabetes Center, Department of Medicine Brigham and Women's Hospital, Boston, Massachusetts
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22
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Romero G, Larner J. Insulin mediators and the mechanism of insulin action. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 1993; 24:21-50. [PMID: 8504064 DOI: 10.1016/s1054-3589(08)60932-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- G Romero
- Department of Pharmacology, University of Pittsburgh School of Medicine, Pennsylvania 15261
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23
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Sheriff S, Fischer JE, Balasubramaniam A. Amylin inhibits insulin-stimulated glucose uptake in C2C12 muscle cell line through a cholera-toxin-sensitive mechanism. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1136:219-22. [PMID: 1504107 DOI: 10.1016/0167-4889(92)90260-i] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Rat amylin inhibits insulin-stimulated glucose uptake with an IC50 of 12.1 +/- 4.1 pM in C2C12 myotubes. The maximal inhibition is 64 +/- 5.4% observed at a 100-pM dose of the peptide. Consistently, presence of 100 pM amylin shifted the dose-response curve of insulin to the right, increasing the ED50 from 0.71 to 16 nM. No effect of amylin is observed on basal glucose uptake in these cells. Cholera-toxin treatment of the cells did not affect the insulin-stimulated glucose uptake, while the inhibitory effect is completely lost in toxin-treated cells. These findings strongly suggest that rat amylin is active at a physiological concentration and the amylin inhibition of glucose uptake is mediated through a cholera-toxin-sensitive mechanism.
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Affiliation(s)
- S Sheriff
- Department of Surgery, University of Cincinnati Medical Center, Ohio 45267
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24
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Incerpi S, Baldini P, Lo Bello M, Luly P. Insulin-dependent release of 5'-nucleotidase and alkaline phosphatase from liver plasma membranes. Biosci Rep 1992; 12:101-8. [PMID: 1330052 DOI: 10.1007/bf02351214] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Insulin treatment of isolated liver plasma membranes induced the release of 5'-nucleotidase and alkaline phosphatase. This effect was maximal at physiological hormone concentrations, being 36% and 17% for 5'-nucleotidase and alkaline phosphatase respectively, and was fully mimicked by the phosphatidylinositol specific phospholipase C (PI-PLC), thus confirming the presence of a glycosylphosphatidylinositol anchoring-system for these exofacial enzymatic proteins. The complete inhibition of insulin dependent enzyme release by neomycin is strongly supportive of an involvement of membrane-located PI-PLC activity. In addition, the insulin-like effect on enzyme release induced by the GTP non-hydrolysable analog, GTP-gamma-S, and its sensitivity to the pertussis toxin are in favour of a mediatory role exerted by the G proteins system, in the transduction of some actions of insulin.
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Affiliation(s)
- S Incerpi
- Department of Biology, University of Rome, Tor Vergata, Italy
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25
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Mortensen ER, Drachman J, Guidotti G. Guanosine nucleotides regulate hormone binding of insulin receptors. Biochem J 1992; 281 ( Pt 3):735-43. [PMID: 1536651 PMCID: PMC1130753 DOI: 10.1042/bj2810735] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Insulin receptors in turkey erythrocyte and rat adipocyte plasma membranes display non-linear hormone binding by Scatchard analysis. This result is consistent with evidence that the insulin-binding sites are heterogeneous and have at least two affinities for the hormone. Mild reduction of plasma membranes with dithiothreitol, before insulin binding, increased the fraction of hormone binding with high affinity without significantly changing the total number of receptor-binding sites. In the presence of guanosine 5'-[gamma-thio]triphosphate, the amount of receptor with high affinity for insulin in the reduced membranes decreased to that present in the absence of reduction; the effect of the nucleotide was concentration- and temperature-dependent. This decrease in insulin binding was specific for guanine nucleotides.
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Affiliation(s)
- E R Mortensen
- Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, MA 02138
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26
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McGeoch JE, Guidotti G. An insulin-stimulated cation channel in skeletal muscle. Inhibition by calcium causes oscillation. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)48359-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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27
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Boege F, Neumann E, Helmreich EJ. Structural heterogeneity of membrane receptors and GTP-binding proteins and its functional consequences for signal transduction. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 199:1-15. [PMID: 1648482 DOI: 10.1111/j.1432-1033.1991.tb16085.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Recent information obtained, mainly by recombinant cDNA technology, on structural heterogeneity of hormone and transmitter receptors, of GTP-binding proteins (G-proteins) and, especially, of G-protein-linked receptors is reviewed and the implications of structural heterogeneity for diversity of hormone and transmitter actions is discussed. For the future, three-dimensional structural analysis of membrane proteins participating in signal transmission and transduction pathways is needed in order to understand the molecular basis of allosteric regulatory mechanisms governing the interactions between these proteins including hysteretic properties and cell-cybernetic aspects.
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Affiliation(s)
- F Boege
- Department of Physiological Chemistry, University of Würzburg, Federal Republic of Germany
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28
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Eckel J, Gerlach-Eskuchen E, Reinauer H. G-protein-mediated regulation of the insulin-responsive glucose transporter in isolated cardiac myocytes. Biochem J 1990; 272:691-6. [PMID: 2176473 PMCID: PMC1149764 DOI: 10.1042/bj2720691] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Isolated muscle cells from adult rat heart were used to study the involvement of G-proteins in the regulation of the glucose transporter by insulin and isoprenaline. Efficient modification of G-protein functions was established by measuring isoprenaline-stimulated cyclic AMP production, viability and ATP content after treating the cells with cholera toxin and pertussis toxin for 2 h. Under these conditions cholera toxin decreased the stimulatory action of insulin on 3-O-methylglucose transport by 56%, but pertussis toxin had no effect. Basal transport was not affected by toxin treatment. Isoprenaline increased 3-O-methylglucose transport by 63%. This effect was not mimicked by dibutyryl cyclic AMP, but was completely blocked by cholera toxin. Streptozotocin-diabetes abolished isoprenaline action and decreased stimulation of transport by 64%. Concomitantly, cholera-toxin sensitivity of glucose transport was lost in cells from diabetic animals. This was paralleled by a large decrease (87 +/- 4%) in mRNA expression of the insulin-regulatable glucose transporter, as shown by Northern-blot analysis of RNA isolated from cardiomyocytes of diabetic rats. These data suggest a functional association between the insulin-responsive glucose transporter and a cholera-toxin-sensitive G-protein mediating stimulation by insulin and isoprenaline.
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Affiliation(s)
- J Eckel
- Diabetes Research Institute, Düsseldorf, Federal Republic of Germany
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