Roles of Ca2+ ions in the control of ChREBP nuclear translocation

J Endocrinol. 2012 May;213(2):115-22. doi: 10.1530/JOE-11-0480. Epub 2012 Mar 8.

Abstract

Carbohydrate-responsive element binding protein (ChREBP (MLXIPL)) is emerging as an important mediator of glucotoxity both in the liver and in the pancreatic β-cells. Although the regulation of its nuclear translocation and transcriptional activation by glucose has been the subject of intensive research, it is still not fully understood. We have recently uncovered a novel mechanism in the excitable pancreatic β-cell where ChREBP interacts with sorcin, a penta-EF-hand Ca(2)(+)-binding protein, and is sequestered in the cytosol at low glucose concentrations. Upon stimulation with glucose and activation of Ca(2)(+) influx, or application of ATP as an intracellular Ca(2)(+)-mobilising agent, ChREBP rapidly translocates to the nucleus. In sorcin-silenced cells, ChREBP is constitutively present in the nucleus, and both glucose and Ca(2)(+) are ineffective in stimulating further ChREBP nuclear shuttling. Whether an active Ca(2)(+)-sorcin element of ChREBP activation also exists in non-excitable cells is discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism*
  • Calcium / physiology*
  • Calcium Signaling / physiology
  • Calcium-Binding Proteins / physiology*
  • Cations, Divalent / metabolism
  • Cell Nucleus / metabolism
  • Cytosol / metabolism
  • Glucose / physiology
  • Humans
  • Insulin-Secreting Cells / metabolism
  • Protein Transport

Substances

  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Calcium-Binding Proteins
  • Cations, Divalent
  • MLXIPL protein, human
  • SRI protein, human
  • Glucose
  • Calcium