Role of the IRE1α-XBP1 axis in IgE-dependent activation of mast cells

The IRE1-XBP1 axis is the most conserved of three major unfolded protein response (UPR) branches that are triggered by the endoplasmic reticulum (ER) stress. Although the transcription factor XBP1 is involved in the development and function of several hematopoietic lineages, the role of XBP1 in the activation of mast cells (MCs) that play key role in allergic response remains largely unknown. Because we have identified salicylaldehyde (SA), which inhibits IRE1 nuclease activity that is essential for production of XBP1, as an inhibitor of MC activation in our previous screening, we investigated the effects of additional IRE1 inhibitors, 3-methyl-6-bromo-salichylaldehyde (MBSA) and KIRA6, targ