A role for the ribosome-associated complex in activation of the IRE1 branch of UPR

I. Hui Wu, Jae Seok Yoon, Qian Yang, Yi Liu, William Skach, Philip Thomas

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The ubiquitous ribosome-associated complex (RAC) is a chaperone that spans ribosomes, making contacts near both the polypeptide exit tunnel and the decoding center, a position prime for sensing and coordinating translation and folding. Loss of RAC is known to result in growth defects and sensitization to translational and osmotic stresses. However, the physiological substrates of RAC and the mechanism(s) by which RAC is involved in responding to specific stresses in higher eukaryotes remain obscure. The data presented here uncover an essential function of mammalian RAC in the unfolded protein response (UPR). Knockdown of RAC sensitizes mammalian cells to endoplasmic reticulum (ER) stress and selectively interferes with IRE1 branch activation. Higher-order oligomerization of the inositol-requiring enzyme 1α (IRE1α) kinase/endoribonuclease depends upon RAC. These results reveal a surveillance function for RAC in the UPR, as follows: modulating IRE1α clustering as required for endonuclease activation and splicing of the substrate Xbp1 mRNA.

Original languageEnglish (US)
Article number109217
JournalCell Reports
Issue number10
StatePublished - Jun 8 2021


  • IRE1 foci
  • UPR
  • Xbp1 mRNA
  • chaperone
  • ribosome stalling
  • ribosome-associated complex
  • translation

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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