Glucose-stimulated Preproinsulin Gene Expression and Nucleartrans-Location of Pancreatic Duodenum Homeobox-1 Require Activation of Phosphatidylinositol 3-Kinase but Not p38 MAPK/SAPK2*

Exposure of islet β-cells to elevated glucose concentrations (30 versus 3 mm) prompts enhanced preproinsulin (PPI) gene transcription and thetrans-location to the nucleoplasm of pancreaticduodenum homeobox-1 (PDX-1; Rafiq, I., Kennedy, H., and Rutter, G. A. (1998) J. Biol. Chem. 273, 23241–23247). Here, we show that in MIN6 β-cells, over-expression of p110.CAAX, a constitutively active form of phosphatidylinositol 3-kinase (PI3K) mimicked the activatory effects of glucose on PPI promoter activity, whereas Δp85, a dominant negative form of the p85 subunit lacking the p110-binding domain, and the PI3K inhibitor LY 294002, blocked these effects. Similarly, glucose-stimulated nucleartrans-location of endogenous PDX-1 was blocked by Δp85 expression, and wortmannin or LY 294002 blocked thetrans-location from the nuclear membrane to the nucleoplasm of epitope-tagged PDX-1.c-myc. By contrast, SB 203580, an inhibitor of stress-activatedprotein kinase-2 (SAPK2)/p38 MAP kinase, had no effect on any of the above parameters, and PPI promoter activity and PDX-1.c-myc localization were unaffected by over-expression of the upstream kinase MKK6 (MAP kinase kinase-6) or wild-type p38/SAPK2, respectively. Furthermore, no change in the activity of extracted p38/SAPK2 could be detected after incubation of cells at either 3 or 30 mm glucose. These data suggest that stimulation of PI3K is necessary and sufficient for the effects of glucose on PPI gene transcription, acting via a downstream signaling pathway that does not involve p38/SAPK2.

[1]  J. Sambrook,et al.  Molecular Cloning: A Laboratory Manual , 2001 .

[2]  H. Kennedy,et al.  Glucose enhances insulin promoter activity in MIN6 beta-cells independently of changes in intracellular Ca2+ concentration and insulin secretion. , 1999, The Biochemical journal.

[3]  G. Rutter,et al.  Insulin secretion: Feed-forward control of insulin biosynthesis? , 1999, Current Biology.

[4]  M. Prentki,et al.  Glucagon-like peptide-1 promotes DNA synthesis, activates phosphatidylinositol 3-kinase and increases transcription factor pancreatic and duodenal homeobox gene 1 (PDX-1) DNA binding activity in beta (INS-1)-cells , 1999, Diabetologia.

[5]  H. Kennedy,et al.  Glucose generates sub-plasma membrane ATP microdomains in single islet beta-cells. Potential role for strategically located mitochondria. , 1999, The Journal of biological chemistry.

[6]  K. Docherty,et al.  Glucose Stimulates Translocation of the Homeodomain Transcription Factor PDX1 from the Cytoplasm to the Nucleus in Pancreatic β-Cells* , 1999, The Journal of Biological Chemistry.

[7]  D. Alessi,et al.  The role of PI 3-kinase in insulin action. , 1998, Biochimica et biophysica acta.

[8]  S. Moule,et al.  The activation of p38 MAPK by the β‐adrenergic agonist isoproterenol in rat epididymal fat cells , 1998, FEBS letters.

[9]  H. Kennedy,et al.  Real-time imaging of gene expression in single living cells. , 1998, Chemistry & biology.

[10]  H. Kennedy,et al.  Glucose-dependent Translocation of Insulin Promoter Factor-1 (IPF-1) between the Nuclear Periphery and the Nucleoplasm of Single MIN6 β-Cells* , 1998, The Journal of Biological Chemistry.

[11]  Gang Xu,et al.  Insulin Receptor Signaling in the β-Cell Influences Insulin Gene Expression and Insulin Content: Evidence for Autocrine β-Cell Regulation , 1998, Diabetes.

[12]  O. Madsen,et al.  Glucose stimulates the activation domain potential of the PDX‐1 homeodomain transcription factor , 1998, FEBS letters.

[13]  P. Berggren,et al.  Exocytosis of insulin promotes insulin gene transcription via the insulin receptor/PI-3 kinase/p70 s6 kinase and CaM kinase pathways. , 1998, Molecular cell.

[14]  J. Tavaré,et al.  Insulin-dependent translocation of ARNO to the plasma membrane of adipocytes requires phosphatidylinositol 3-kinase , 1998, Current Biology.

[15]  Jiahuai Han,et al.  The Stress Inducer Arsenite Activates Mitogen-activated Protein Kinases Extracellular Signal-regulated Kinases 1 and 2 via a MAPK Kinase 6/p38-dependent Pathway* , 1998, The Journal of Biological Chemistry.

[16]  P. Cohen,et al.  Activation of the novel MAP kinase homologue SAPK4 by cytokines and cellular stresses is mediated by SKK3 (MKK6). , 1997, Biochemical Society transactions.

[17]  E. Sheader,et al.  Glucose‐induced swelling in rat pancreatic β‐cells , 1997 .

[18]  P. Cohen,et al.  The p38/Reactivating Kinase Mitogen-activated Protein Kinase Cascade Mediates the Activation of the Transcription Factor Insulin Upstream Factor 1 and Insulin Gene Transcription by High Glucose in Pancreatic β-Cells* , 1997, The Journal of Biological Chemistry.

[19]  H. Kennedy,et al.  Upstream Stimulatory Factor-2 (USF2) Activity Is Required for Glucose Stimulation of L-Pyruvate Kinase Promoter Activity in Single Living Islet β-Cells* , 1997, The Journal of Biological Chemistry.

[20]  M. Cobb,et al.  Activation of mitogen-activating protein kinase by glucose is not required for insulin secretion. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[21]  F. Melchior,et al.  A Small Ubiquitin-Related Polypeptide Involved in Targeting RanGAP1 to Nuclear Pore Complex Protein RanBP2 , 1997, Cell.

[22]  E. Cerasi,et al.  Purification of the beta-cell glucose-sensitive factor that transactivates the insulin gene differentially in normal and transformed islet cells. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[23]  G. Rutter,et al.  Subcellular imaging of intramitochondrial Ca2+ with recombinant targeted aequorin: significance for the regulation of pyruvate dehydrogenase activity. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[24]  Jiahuai Han,et al.  Characterization of the Structure and Function of a Novel MAP Kinase Kinase (MKK6) (*) , 1996, The Journal of Biological Chemistry.

[25]  Philip R. Cohen,et al.  PD 098059 Is a Specific Inhibitor of the Activation of Mitogen-activated Protein Kinase Kinase in Vitro and in Vivo(*) , 1995, The Journal of Biological Chemistry.

[26]  W. Rutter,et al.  The Insulin Gene Promoter: A Simplified Nomenclature , 1995, Diabetes.

[27]  Philip R. Cohen,et al.  SB 203580 is a specific inhibitor of a MAP kinase homologue which is stimulated by cellular stresses and interleukin‐1 , 1995, FEBS letters.

[28]  W. Fantl,et al.  Ras-dependent induction of cellular responses by constitutively active phosphatidylinositol-3 kinase. , 1995, Science.

[29]  B. Dérijard,et al.  Transcription factor ATF2 regulation by the JNK signal transduction pathway , 1995, Science.

[30]  O. Madsen,et al.  Transcriptional regulation of the human insulin gene is dependent on the homeodomain protein STF1/IPF1 acting through the CT boxes. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[31]  K. Docherty,et al.  Glucose modulates the binding activity of the beta-cell transcription factor IUF1 in a phosphorylation-dependent manner. , 1994, The Biochemical journal.

[32]  Michel Morange,et al.  A novel kinase cascade triggered by stress and heat shock that stimulates MAPKAP kinase-2 and phosphorylation of the small heat shock proteins , 1994, Cell.

[33]  L Bibbs,et al.  A MAP kinase targeted by endotoxin and hyperosmolarity in mammalian cells. , 1994, Science.

[34]  J. Habener,et al.  IDX‐1: a new homeodomain transcription factor expressed in rat pancreatic islets and duodenum that transactivates the somatostatin gene. , 1994, The EMBO journal.

[35]  M. Kasuga,et al.  PI 3‐kinase: structural and functional analysis of intersubunit interactions. , 1994, The EMBO journal.

[36]  H. Ohlsson,et al.  IPF1, a homeodomain‐containing transactivator of the insulin gene. , 1993, The EMBO journal.

[37]  V. Niggli,et al.  The PKC-inhibitor Ro 31-8220 selectively suppresses PMA- and diacylglycerol-induced fluid pinocytosis and actin polymerization in PMNs. , 1993, Biochemical and biophysical research communications.

[38]  S. Efrat,et al.  Glucose induces insulin gene transcription in a murine pancreatic beta-cell line. , 1991, The Journal of biological chemistry.

[39]  J. Miyazaki,et al.  Establishment of a pancreatic beta cell line that retains glucose-inducible insulin secretion: special reference to expression of glucose transporter isoforms. , 1990, Endocrinology.

[40]  K. Docherty,et al.  Positive and negative regulation of the human insulin gene by multiple trans-acting factors. , 1990, The Journal of biological chemistry.

[41]  M. Ptashne,et al.  A vector for expressing GAL4(1-147) fusions in mammalian cells. , 1989, Nucleic acids research.

[42]  R. Germain,et al.  Efficient cell surface expression of class II MHC molecules in the absence of associated invariant chain , 1986, The Journal of experimental medicine.

[43]  M. Welsh,et al.  Effects of D-glucose, L-leucine, and 2-ketoisocaproate on Insulin mRNA Levels in Mouse Pancreatic Islets , 1986, Diabetes.

[44]  D. Steiner,et al.  Control of insulin gene expression in pancreatic beta-cells and in an insulin-producing cell line, RIN-5F cells. II. Regulation of insulin mRNA stability. , 1985, The Journal of biological chemistry.

[45]  D. Steiner,et al.  Control of insulin gene expression in pancreatic beta-cells and in an insulin-producing cell line, RIN-5F cells. I. Effects of glucose and cyclic AMP on the transcription of insulin mRNA. , 1985, The Journal of biological chemistry.

[46]  H. Okamoto,et al.  Translational control of proinsulin synthesis by glucose , 1980, Nature.

[47]  C. J. Hedeskov,et al.  The effect of sugars on (pro)insulin biosynthesis. , 1978, The Biochemical journal.

[48]  M. Permutt,et al.  Insulin biosynthesis. I. On the mechanism of glucose stimulation. , 1972, The Journal of biological chemistry.

[49]  F. Ashcroft,et al.  Electrophysiology of the pancreatic beta-cell. , 1989, Progress in biophysics and molecular biology.