6SHC

Crystal structure of human IRE1 luminal domain Q105C

Summary for 6SHC

• Entry DOI: 10.2210/pdb6shc/pdb
• Descriptor: Serine/threonine-protein kinase/endoribonuclease IRE1 (1 entity in total)
• Functional Keywords: ire1, unfolded protein response, er stress, protein quality control, signaling protein
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 1
• Total formula weight: 41006.37

Authors

Yan, Y.,Ron, D. (deposition date: 2019-08-06, release date: 2020-01-08, Last modification date: 2024-10-23)

Primary citation

Amin-Wetzel, N.,Neidhardt, L.,Yan, Y.,Mayer, M.P.,Ron, D.
Unstructured regions in IRE1 alpha specify BiP-mediated destabilisation of the luminal domain dimer and repression of the UPR.
Elife, 8:-, 2019

PubMed Abstract: Coupling of endoplasmic reticulum (ER) stress to dimerisation-dependent activation of the UPR transducer IRE1 is incompletely understood. Whilst the luminal co-chaperone ERdj4 promotes a complex between the Hsp70 BiP and IRE1's stress-sensing luminal domain (IRE1) that favours the latter's monomeric inactive state and loss of ERdj4 de-represses IRE1, evidence linking these cellular and in vitro observations is presently lacking. We report that enforced loading of endogenous BiP onto endogenous IRE1α repressed UPR signalling in CHO cells and deletions in the IRE1α locus that de-repressed the UPR in cells, encode flexible regions of IRE1 that mediated BiP-induced monomerisation in vitro. Changes in the hydrogen exchange mass spectrometry profile of IRE1 induced by ERdj4 and BiP confirmed monomerisation and were consistent with active destabilisation of the IRE1 dimer. Together, these observations support a competition model whereby waning ER stress passively partitions ERdj4 and BiP to IRE1 to initiate active repression of UPR signalling.

PubMed: 31873072
DOI: 10.7554/eLife.50793

Experimental method

X-RAY DIFFRACTION (3.55 Å)