Glucose regulation of insulin gene expression in pancreatic beta-cells

Biochem J. 2008 Oct 1;415(1):1-10. doi: 10.1042/BJ20081029.

Abstract

Production and secretion of insulin from the beta-cells of the pancreas is very crucial in maintaining normoglycaemia. This is achieved by tight regulation of insulin synthesis and exocytosis from the beta-cells in response to changes in blood glucose levels. The synthesis of insulin is regulated by blood glucose levels at the transcriptional and post-transcriptional levels. Although many transcription factors have been implicated in the regulation of insulin gene transcription, three beta-cell-specific transcriptional regulators, Pdx-1 (pancreatic and duodenal homeobox-1), NeuroD1 (neurogenic differentiation 1) and MafA (V-maf musculoaponeurotic fibrosarcoma oncogene homologue A), have been demonstrated to play a crucial role in glucose induction of insulin gene transcription and pancreatic beta-cell function. These three transcription factors activate insulin gene expression in a co-ordinated and synergistic manner in response to increasing glucose levels. It has been shown that changes in glucose concentrations modulate the function of these beta-cell transcription factors at multiple levels. These include changes in expression levels, subcellular localization, DNA-binding activity, transactivation capability and interaction with other proteins. Furthermore, all three transcription factors are able to induce insulin gene expression when expressed in non-beta-cells, including liver and intestinal cells. The present review summarizes the recent findings on how glucose modulates the function of the beta-cell transcription factors Pdx-1, NeuroD1 and MafA, and thereby tightly regulates insulin synthesis in accordance with blood glucose levels.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / physiology*
  • Blood Glucose / physiology*
  • Gene Expression Regulation
  • Histone Deacetylases / physiology
  • Homeodomain Proteins / physiology*
  • Humans
  • Insulin / biosynthesis*
  • Insulin / genetics
  • Insulin-Secreting Cells / drug effects*
  • Insulin-Secreting Cells / physiology*
  • Maf Transcription Factors, Large / physiology*
  • Nerve Tissue Proteins / physiology*
  • Protein Transport
  • Trans-Activators / physiology*

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Blood Glucose
  • Homeodomain Proteins
  • Insulin
  • MAFA protein, human
  • Maf Transcription Factors, Large
  • Nerve Tissue Proteins
  • Trans-Activators
  • pancreatic and duodenal homeobox 1 protein
  • Neurogenic differentiation factor 1
  • Histone Deacetylases