Metabolite Regulation of Nuclear Localization of Carbohydrate-response Element-binding Protein (ChREBP): ROLE OF AMP AS AN ALLOSTERIC INHIBITOR

J Biol Chem. 2016 May 13;291(20):10515-27. doi: 10.1074/jbc.M115.708982. Epub 2016 Mar 16.

Abstract

The carbohydrate-response element-binding protein (ChREBP) is a glucose-responsive transcription factor that plays an essential role in converting excess carbohydrate to fat storage in the liver. In response to glucose levels, ChREBP is regulated by nuclear/cytosol trafficking via interaction with 14-3-3 proteins, CRM-1 (exportin-1 or XPO-1), or importins. Nuclear localization of ChREBP was rapidly inhibited when incubated in branched-chain α-ketoacids, saturated and unsaturated fatty acids, or 5-aminoimidazole-4-carboxamide ribonucleotide. Here, we discovered that protein-free extracts of high fat-fed livers contained, in addition to ketone bodies, a new metabolite, identified as AMP, which specifically activates the interaction between ChREBP and 14-3-3. The crystal structure showed that AMP binds directly to the N terminus of ChREBP-α2 helix. Our results suggest that AMP inhibits the nuclear localization of ChREBP through an allosteric activation of ChREBP/14-3-3 interactions and not by activation of AMPK. AMP and ketone bodies together can therefore inhibit lipogenesis by restricting localization of ChREBP to the cytoplasm during periods of ketosis.

Keywords: AMP; ChREBP; allosteric regulation; glucose metabolism; glucose sensing; hepatocyte; ketogenesis; lipogenesis; nuclear localization.

Publication types

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

MeSH terms

  • 14-3-3 Proteins / metabolism
  • AMP-Activated Protein Kinases / metabolism
  • Adenosine Monophosphate / metabolism*
  • Allosteric Regulation
  • Animals
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / chemistry
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism*
  • Cell Nucleus / metabolism
  • Cells, Cultured
  • Crystallography, X-Ray
  • Diet, High-Fat
  • Dietary Sucrose / administration & dosage
  • Hepatocytes / metabolism
  • Karyopherins / metabolism
  • Ketone Bodies / metabolism
  • Male
  • Models, Biological
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Cytoplasmic and Nuclear / metabolism

Substances

  • 14-3-3 Proteins
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Dietary Sucrose
  • Karyopherins
  • Ketone Bodies
  • Receptors, Cytoplasmic and Nuclear
  • Wbscr14 protein, rat
  • exportin 1 protein
  • Adenosine Monophosphate
  • AMP-Activated Protein Kinases

Associated data

  • PDB/4GNT
  • PDB/5F74