SP600125 inhibits cap-dependent translation independently of the c-Jun N-terminal kinase pathway

Masatoshi Ito, Hiroshi Kitamura, Chisato Kikuguchi, Koji Hase, Hiroshi Ohno, Osamu Ohara

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We investigated the effects of SP600125 (formerly called c-Jun N-terminal kinase (JNK) inhibitor II) on translation using cultured mouse cells. SP600125 (50 μM) treatment rapidly repressed overall protein synthesis, accompanied by a reduction in the mRNAs for housekeeping genes such as glyceraldehyde-3-phosphate dehydrogenase in the polysomal fraction. SP600125 decreased polysomes with a concomitant increase in free ribosomal subunits in the cytoplasm, suggesting that global translation was inhibited at the initiation step. A reporter analysis using exogenous mRNAs showed that SP600125 inhibited cap-dependent but not internal ribosome entry site-dependent translation. SP600125 significantly attenuated phosphorylation of components in the mTOR pathway, which is responsible for cap-dependent translation. In contrast to SP600125, short hairpin RNAs for JNK1 and JNK2 failed to affect overall protein synthesis. Collectively, SP600125 inhibits cap-dependent translation, independent of the JNK pathway.

Original languageEnglish
Pages (from-to)27-33
Number of pages7
JournalCell structure and function
Volume36
Issue number1
DOIs
Publication statusPublished - 2011 Apr 18
Externally publishedYes

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Keywords

  • Cap-dependent translation
  • Polysome
  • SP600125
  • c-jun N-terminal kinase

ASJC Scopus subject areas

  • Physiology
  • Molecular Biology
  • Cell Biology

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