Casein kinase 2 phosphorylates and stabilizes C/EBPβ in pancreatic β cells

Biochem Biophys Res Commun. 2018 Feb 26;497(1):451-456. doi: 10.1016/j.bbrc.2018.02.108. Epub 2018 Feb 12.

Abstract

During the development of type 2 diabetes, endoplasmic reticulum (ER) stress leads to pancreatic β cell failure. CCAAT/enhancer-binding protein (C/EBP) β is highly induced by ER stress and AMP-activated protein kinase (AMPK) suppression in pancreatic β cells, and its accumulation reduces pancreatic β cell mass. We investigated the phosphorylation state of C/EBPβ under these conditions. Casein kinase 2 (CK2) was found to co-localize with C/EBPβ in MIN6 cells. It phosphorylated S222 of C/EBPβ, a previously unidentified phosphorylation site. We found that C/EBPβ is phosphorylated by CK2 under AMPK suppression and ER stress, which are important from the viewpoint of the worsening pathological condition of type 2 diabetes, such as decreased insulin secretion and apoptosis of pancreatic β cells.

Keywords: CCAAT/Enhancer-binding protein β (C/EBPβ); Casein kinase 2 (CK2); Endoplasmic reticulum stress; Pancreatic β cell failure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinase Kinases
  • Animals
  • CCAAT-Enhancer-Binding Protein-beta / metabolism*
  • Casein Kinase II / metabolism*
  • Cell Line
  • Endoplasmic Reticulum Stress / physiology*
  • Insulin-Secreting Cells / metabolism*
  • Mice
  • Phosphorylation
  • Protein Kinases / metabolism*

Substances

  • CCAAT-Enhancer-Binding Protein-beta
  • Protein Kinases
  • Casein Kinase II
  • AMP-Activated Protein Kinase Kinases