IRE1α (14C10) Rabbit mAb #3294

The secretory, intra-organellar and transmembrane proteins translocate into the endoplasmic reticulum (ER) after their synthesis. Inside the ER, they are post-translationally modified and properly folded. Disruptions of ER homeostasis leads to the accumulation of unfolded proteins (1). The ER has developed an adaptive mechanism called unfolded protein response (UPR) to counteract compromised protein folding (1). One of the players in UPR, IRE1, was first identified in Saccharomyces cerevisiae as a transmembrane serine/threonine kinase (2-4). This kinase was proposed to be a proximal sensor for UPR that transmits the unfolded protein signal across the ER membrane (3,4). A human homolog of this kinase, IRE1α, was later identified and shown to be ubiquitously expressed in human tissues (5). Upon activation of UPR, IRE1α splices X-box binding protein (XBP1) mRNA by an unconventional mechanism using its endoribonuclease activity (6). This converts XBP1 into a potent transcriptional activator that induces many UPR responsive genes (6). Recently, IRE1α was shown to mediate the rapid degradation of certain mRNAs based on the ER-localization and primary sequences of their encoded proteins, suggesting a novel mechanism in UPR (7).