| Structural highlights
Function
[ERN1_HUMAN] Senses unfolded proteins in the lumen of the endoplasmic reticulum via its N-terminal domain which leads to enzyme auto-activation. The active endoribonuclease domain splices XBP1 mRNA to generate a new C-terminus, converting it into a potent unfolded-protein response transcriptional activator and triggering growth arrest and apoptosis.[1] [2] [3] [UniProtKB:Q9EQY0]
Publication Abstract from PubMed
A series of imidazo[1,2-b]pyridazin-8-amine kinase inhibitors was discovered to allosterically inhibit the endoribonuclease function of the dual kinase-endoribonuclease inositol-requiring enzyme 1alpha (IRE1alpha), a key component of the unfolded protein response in mammalian cells and a potential drug target in multiple human diseases. Inhibitor optimization gave compounds with high kinome selectivity that prevented endoplasmic reticulum stress-induced IRE1alpha oligomerization and phosphorylation, and inhibited endoribonuclease activity in human cells. X-ray crystallography showed the inhibitors to bind to a previously unreported and unusually disordered conformation of the IRE1alpha kinase domain that would be incompatible with back-to-back dimerization of the IRE1alpha protein and activation of the endoribonuclease function. These findings increase the repertoire of known IRE1alpha protein conformations and can guide the discovery of highly selective ligands for the IRE1alpha kinase site that allosterically inhibit the endoribonuclease.
Binding to an unusual inactive kinase conformation by highly selective inhibitors of inositol-requiring enzyme 1alpha kinase-endoribonuclease.,Colombano G, Caldwell JJ, Matthews TP, Bhatia C, Joshi A, McHardy T, Mok NY, Newbatt Y, Pickard L, Strover J, Hedayat S, Walton MI, Myers S, Jones AM, Saville H, McAndrew C, Burke R, Eccles S, Davies F, Bayliss R, Collins I J Med Chem. 2019 Feb 19. doi: 10.1021/acs.jmedchem.8b01721. PMID:30779566[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Tirasophon W, Welihinda AA, Kaufman RJ. A stress response pathway from the endoplasmic reticulum to the nucleus requires a novel bifunctional protein kinase/endoribonuclease (Ire1p) in mammalian cells. Genes Dev. 1998 Jun 15;12(12):1812-24. PMID:9637683
- ↑ Iwawaki T, Hosoda A, Okuda T, Kamigori Y, Nomura-Furuwatari C, Kimata Y, Tsuru A, Kohno K. Translational control by the ER transmembrane kinase/ribonuclease IRE1 under ER stress. Nat Cell Biol. 2001 Feb;3(2):158-64. PMID:11175748 doi:10.1038/35055065
- ↑ Liu CY, Xu Z, Kaufman RJ. Structure and intermolecular interactions of the luminal dimerization domain of human IRE1alpha. J Biol Chem. 2003 May 16;278(20):17680-7. Epub 2003 Mar 13. PMID:12637535 doi:10.1074/jbc.M300418200
- ↑ Colombano G, Caldwell JJ, Matthews TP, Bhatia C, Joshi A, McHardy T, Mok NY, Newbatt Y, Pickard L, Strover J, Hedayat S, Walton MI, Myers S, Jones AM, Saville H, McAndrew C, Burke R, Eccles S, Davies F, Bayliss R, Collins I. Binding to an unusual inactive kinase conformation by highly selective inhibitors of inositol-requiring enzyme 1alpha kinase-endoribonuclease. J Med Chem. 2019 Feb 19. doi: 10.1021/acs.jmedchem.8b01721. PMID:30779566 doi:http://dx.doi.org/10.1021/acs.jmedchem.8b01721
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