O-GlcNAcylation of eIF2α regulates the phospho-eIF2α-mediated ER stress response

Insook Jang, Han Byeol Kim, Hojoong Seo, Jin Young Kim, Hyeonjin Choi, Jong Shin Yoo, Jae woo Kim, Jin Won Cho

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

O-GlcNAcylation is highly involved in cellular stress responses including the endoplasmic reticulum (ER) stress response. For example, glucosamine-induced flux through the hexosamine biosynthetic pathway can promote ER stress and ER stress inducers can change the total cellular level of O-GlcNAcylation. However, it is largely unknown which component(s) of the unfolded protein response (UPR) is directly regulated by O-GlcNAcylation. In this study, eukaryotic translation initiation factor 2α (eIF2α), a major branch of the UPR, was O-GlcNAcylated at Ser 219, Thr 239, and Thr 241. Upon ER stress, eIF2α is phosphorylated at Ser 51 by phosphorylated PKR-like ER kinase and this inhibits global translation initiation, except for that of specific mRNAs, including activating transcription factor 4, that induce stress-responsive genes such as C/EBP homologous protein (CHOP). Hyper-. O-GlcNAcylation induced by O-GlcNAcase inhibitor (thiamet-G) treatment or O-GlcNAc transferase (OGT) overexpression hindered phosphorylation of eIF2α at Ser 51. The level of O-GlcNAcylation of eIF2α was changed by dithiothreitol treatment dependent on its phosphorylation at Ser 51. Point mutation of the O-GlcNAcylation sites of eIF2α increased its phosphorylation at Ser 51 and CHOP expression and resulted in increased apoptosis upon ER stress. These results suggest that O-GlcNAcylation of eIF2α affects its phosphorylation at Ser 51 and influences CHOP-mediated cell death. This O-GlcNAcylation of eIF2α was reproduced in thiamet-G-injected mouse liver. In conclusion, proper regulation of O-GlcNAcylation and phosphorylation of eIF2α is important to maintain cellular homeostasis upon ER stress.

Original languageEnglish
Pages (from-to)1860-1869
Number of pages10
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Volume1853
Issue number8
DOIs
Publication statusPublished - 2015 Aug 1

Bibliographical note

Funding Information:
We thank Tae Ho Lee (Seoul), Joo Hun Lee (Seoul), Young Jun Oh (Seoul), and Nam-on Ku (Seoul) for critical reading of the manuscript. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( NRF-2013R1A2A1A01008067 ) to J.W.C. MS analysis was supported by a Korea Basic Science Institute grant (T34750) to Jin Young Kim.

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'O-GlcNAcylation of eIF2α regulates the phospho-eIF2α-mediated ER stress response'. Together they form a unique fingerprint.

Cite this