This entry includes IRE1/2 and related proteins. Human IRE1 is a transmembrane protein kinase essential for the endoplasmic reticulum (ER) unfolded protein response (UPR) [, , , , , ]. IRE1 is activated by autophosphorylation through its cytoplasmic kinase domain, and this leads to activation of the C-terminal ribonuclease domain, which splices Xbp1 mRNA generating an active Xbp1s transcriptional activator [].Human IRE2 induces translational repression through 28S ribosomal RNA cleavage in response to ER stress []. However, mouse IRE2 does not have this function, instead, it plays a role in expression of the DDIT3 transcription factor, required for the unfolded-protein response, growth arrest and apoptosis [].
