Insulin regulates the activity of forkhead transcription factor Hnf-3β/Foxa-2 by Akt-mediated phosphorylation and nuclear/cytosolic localization

Hepatocyte nuclear factors 3 α, β, and γ (Foxa-1, -2, and -3) are transcriptional activators of important metabolic genes in the liver that are suppressed by the actions of insulin. Here, we show that the activation of phosphatidylinositol 3-kinase–Akt by insulin induces Foxa-2 phosphorylation, nuclear exclusion, and inhibition of Foxa-2-dependent transcriptional activity. Foxa-2 physically interacts with Akt, a key mediator of the phosphatidylinositol 3-kinase pathway and is phosphorylated at a single conserved site (T156) that is absent in Foxa-1 and Foxa-3 proteins. This Akt phosphorylation site in Foxa-2 is highly conserved from mammals to insects. Mutant Foxa-2T156A is resistant to Akt-mediated phosphorylation, nuclear exclusion, and transcriptional inactivation of Foxa-2-regulated gene expression. These results implicate an evolutionarily conserved mechanism in the regulation of Foxa-2-dependent transcriptional control by extracellular signals such as insulin.

[1]  Matthias Blüher,et al.  Extended Longevity in Mice Lacking the Insulin Receptor in Adipose Tissue , 2003, Science.

[2]  D. Pipeleers,et al.  Glucose-regulated gene expression maintaining the glucose-responsive state of beta-cells. , 2002, Diabetes.

[3]  K. Kaestner,et al.  Foxa2 Controls Pdx1 Gene Expression in Pancreatic β-Cells In Vivo , 2002 .

[4]  M. Permutt,et al.  Islet β cell expression of constitutively active Akt1/PKBα induces striking hypertrophy, hyperplasia, and hyperinsulinemia , 2001 .

[5]  D. Accili,et al.  The forkhead transcription factor Foxo1 (Fkhr) confers insulin sensitivity onto glucose-6-phosphatase expression. , 2001, The Journal of clinical investigation.

[6]  M. Birnbaum,et al.  Akt1/PKBα Is Required for Normal Growth but Dispensable for Maintenance of Glucose Homeostasis in Mice* , 2001, The Journal of Biological Chemistry.

[7]  E. Furth,et al.  Regulation of pancreatic β-cell growth and survival by the serine/threonine protein kinase Akt1/PKBα , 2001, Nature Medicine.

[8]  R A Roth,et al.  Differential regulation of endogenous glucose-6-phosphatase and phosphoenolpyruvate carboxykinase gene expression by the forkhead transcription factor FKHR in H4IIE-hepatoma cells. , 2001, Biochemical and biophysical research communications.

[9]  K. Kaestner,et al.  Tissue-specific deletion of Foxa2 in pancreatic beta cells results in hyperinsulinemic hypoglycemia. , 2001, Genes & development.

[10]  K. Kaestner,et al.  Insulin Resistance and a Diabetes Mellitus-Like Syndrome in Mice Lacking the Protein Kinase Akt2 (PKBβ) , 2001 .

[11]  B. Hemmings,et al.  Protein Kinase B β/Akt2 Plays a Specific Role in Muscle Differentiation* , 2001, The Journal of Biological Chemistry.

[12]  Toshiyuki Obata,et al.  Peptide and Protein Library Screening Defines Optimal Substrate Motifs for AKT/PKB* , 2000, The Journal of Biological Chemistry.

[13]  N. Daigle,et al.  Hepatocyte Nuclear Factor 3β (Foxa2) Is Dispensable for Maintaining the Differentiated State of the Adult Hepatocyte , 2000, Molecular and Cellular Biology.

[14]  R. O’Brien,et al.  Differential Role of Hepatocyte Nuclear Factor-1 in the Regulation of Glucose-6-phosphatase Catalytic Subunit Gene Transcription by cAMP in Liver- and Kidney-derived Cell Lines* , 2000, The Journal of Biological Chemistry.

[15]  M. Stoffel,et al.  Pancreatic beta cell-specific transcription of the pdx-1 gene. The role of conserved upstream control regions and their hepatic nuclear factor 3beta sites. , 2000, The Journal of biological chemistry.

[16]  S. R. Datta,et al.  Cellular survival: a play in three Akts. , 1999, Genes & development.

[17]  M. Stoffel,et al.  Impaired glucose homeostasis and neonatal mortality in hepatocyte nuclear factor 3alpha-deficient mice. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[18]  M. Kasuga,et al.  Dominant Negative Forms of Akt (Protein Kinase B) and Atypical Protein Kinase Cλ Do Not Prevent Insulin Inhibition of Phosphoenolpyruvate Carboxykinase Gene Transcription* , 1999, The Journal of Biological Chemistry.

[19]  Geert J. P. L. Kops,et al.  Direct control of the Forkhead transcription factor AFX by protein kinase B , 1999, Nature.

[20]  M. Greenberg,et al.  Akt Promotes Cell Survival by Phosphorylating and Inhibiting a Forkhead Transcription Factor , 1999, Cell.

[21]  Klaus H. Kaestner,et al.  Targeted Disruption of the Gene Encoding Hepatocyte Nuclear Factor 3γ Results in Reduced Transcription of Hepatocyte-Specific Genes , 1998, Molecular and Cellular Biology.

[22]  P. Cohen,et al.  Activation of protein kinase B beta and gamma isoforms by insulin in vivo and by 3-phosphoinositide-dependent protein kinase-1 in vitro: comparison with protein kinase B alpha. , 1998, The Biochemical journal.

[23]  P. Cohen,et al.  Role of Translocation in the Activation and Function of Protein Kinase B* , 1997, The Journal of Biological Chemistry.

[24]  G. Ruvkun,et al.  The Fork head transcription factor DAF-16 transduces insulin-like metabolic and longevity signals in C. elegans , 1997, Nature.

[25]  S. R. Datta,et al.  Akt Phosphorylation of BAD Couples Survival Signals to the Cell-Intrinsic Death Machinery , 1997, Cell.

[26]  David R. Kaplan,et al.  Direct Regulation of the Akt Proto-Oncogene Product by Phosphatidylinositol-3,4-bisphosphate , 1997, Science.

[27]  P. Cohen,et al.  Molecular basis for the substrate specificity of protein kinase B; comparison with MAPKAP kinase‐1 and p70 S6 kinase , 1996, FEBS letters.

[28]  M. Andjelkovic,et al.  Activation and phosphorylation of a pleckstrin homology domain containing protein kinase (RAC-PK/PKB) promoted by serum and protein phosphatase inhibitors. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[29]  P. Cohen,et al.  Inhibition of glycogen synthase kinase-3 by insulin mediated by protein kinase B , 1995, Nature.

[30]  D. Shafritz,et al.  Transcription factor and liver-specific mRNA expression in facultative epithelial progenitor cells of liver and pancreas. , 1995, The American journal of pathology.

[31]  Andrius Kazlauskas,et al.  The protein kinase encoded by the Akt proto-oncogene is a target of the PDGF-activated phosphatidylinositol 3-kinase , 1995, Cell.

[32]  J. Wang,et al.  Hepatic nuclear factor 3- and hormone-regulated expression of the phosphoenolpyruvate carboxykinase and insulin-like growth factor-binding protein 1 genes , 1995, Molecular and cellular biology.

[33]  F. Bosch,et al.  Transgenic mice overexpressing phosphoenolpyruvate carboxykinase develop non-insulin-dependent diabetes mellitus. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[34]  G. Ruvkun,et al.  daf-2, daf-16 and daf-23: genetically interacting genes controlling Dauer formation in Caenorhabditis elegans. , 1994, Genetics.

[35]  C. Kenyon,et al.  A C. elegans mutant that lives twice as long as wild type , 1993, Nature.

[36]  J. Darnell,et al.  Sequential expression of HNF-3β and HNF-3α by embryonic organizing centers: the dorsal lip/node, notochord and floor plate , 1993, Mechanisms of Development.

[37]  G. Rousseau,et al.  Liver-specific factor binding to the liver promoter of a 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene. , 1993, The Journal of biological chemistry.

[38]  R. Brennan.  The winged-helix DNA-binding motif: Another helix-turn-helix takeoff , 1993, Cell.

[39]  D. Granner,et al.  Inhibition of transcription of the phosphoenolpyruvate carboxykinase gene by insulin , 1983, Nature.

[40]  J. Sadoshima,et al.  Glycogen synthase kinase-3beta: a novel regulator of cardiac hypertrophy and development. , 2002, Circulation research.

[41]  D. Powell,et al.  Hepatic nuclear factor 3 and high mobility group I/Y proteins bind the insulin response element of the insulin-like growth factor-binding protein-1 promoter. , 1997, Endocrinology.

[42]  L. Lim,et al.  Hepatocyte Nuclear Factor 3 / fork head Homolog 11 Is Expressed in Proliferating Epithelial and Mesenchymal Cells of Embryonic and Adult Tissues , 1996 .

[43]  Klaus H. Kaestner,et al.  The HNF-3 gene family of transcription factors in mice: gene structure, cDNA sequence, and mRNA distribution. , 1994, Genomics.