KIRA6

The IRE1 pathway is a component of the unfolded protein response that senses unfolded proteins via an ER luminal domain that becomes oligomerized during stress. It is associated with promoting cell survival through the activity of the IRE1α RNase, whose activity upregulates proteins that enhance ER protein folding and quality control. However, under high ER stress, the IRE1α RNase becomes hyperactive and is less discriminant in its substrate specificity, endonucleolytically cleaving many additional mRNAs that localize to the ER membrane, leading to cell proliferation blocks, inflammation, and apoptosis. KIRA6 is an ATP-competitive IRE1α kinase inhibiting RNase attenuator (KIRA) that allosterically inhibits IRE1α RNase kinase activity (IC50 = 0.6 μM) and prevents oligomerization. It has been shown to inhibit IRE1α in vivo and to promote cell survival under ER stress. At 20 μg/ml, KIRA6 is reported to preserve photoreceptor functional viability in rat models of ER stress-induced retinal degeneration. At 5 mg/kg, it has also been shown to preserve pancreatic β cells, increase insulin, and reduce hyperglycemia in Akita diabetic mice.