
Major Claims • IRE1 initiates an XBP-1 independent pathway during the unfolding protein response • IRE1 nuclease has a broader range of substrates than XBP-1 • IRE1 mediates the rapid degradation of a subset of mRNA • Degradation is dependent on ER localization and peptide sequence
No treatment Actinomycin D Treat with DTT Treat with both
3’ fragment 5’ fragment
Conclusions • IRE1 mediates repression of ER targeted mRNA • Repression is due to mRNA stability not transcription • Cleavage of mRNA initiates degradation • mRNA decay requires cotranslational translocation and translation of the correct peptide