9GOW | pdb_00009gow

Crystal structure of phosphorylated human IRE1a in complex with IA107


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.00 Å
  • R-Value Free: 
    0.281 (Depositor), 0.280 (DCC) 
  • R-Value Work: 
    0.231 (Depositor), 0.231 (DCC) 
  • R-Value Observed: 
    0.234 (Depositor) 

Starting Model: experimental
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Literature

Harnessing indole scaffolds to identify small-molecule IRE1 alpha inhibitors modulating XBP1 mRNA splicing.

Liu, Y.Avathan Veettil, A.K.Gasper, R.Jiang, M.Wagner, L.Hasturk, O.Wu, P.

(2025) Nat Commun 16: 8531-8531

  • DOI: https://doi.org/10.1038/s41467-025-64291-4
  • Primary Citation of Related Structures:  
    9GOW

  • PubMed Abstract: 

    The inositol-requiring enzyme 1 alpha (IRE1α) is an important sensor protein with dual kinase and ribonuclease function. It induces X-box binding protein 1 (XBP1) mRNA splicing and mediates endoplasmic reticulum (ER) stress-triggered downstream unfolded protein response signaling pathways. The dysregulation of IRE1α has been associated with multiple human diseases, and thus IRE1α-targeting small molecules harbor great therapeutic potential. We herein report a series of substituted indoles as IRE1α inhibitors (such as IA107) of excellent potency and selectivity. We also report a resolved co-crystal structure that reveals a unique inhibition mode of IA107 that allosterically inhibits IRE1α RNase activity via binding to the IRE1α kinase domain but without inhibiting the IRE1α dimerization. The following cellular evaluation results demonstrate that IA107 concentration-dependently inhibits the cellular ER stress-induced XBP1 mRNA splicing, and the ester-containing prodrug exhibits a ~ 50-fold increase in cellular activity. Collectively, our results establish the indoles as a potent and selective IRE1α-inhibiting chemotype that modulates RNA splicing and expands the biological application potential associated with IRE1α targeting via small molecules.


  • Organizational Affiliation
    • Chemical Genomics Centre, Max Planck Institute of Molecular Physiology, Dortmund, Germany.

Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Serine/threonine-protein kinase/endoribonuclease IRE1
A, B, C, D
434Homo sapiensMutation(s): 0 
Gene Names: ERN1IRE1
EC: 2.7.11.1 (PDB Primary Data), 3.1.26 (PDB Primary Data)
UniProt & NIH Common Fund Data Resources
Find proteins for O75460 (Homo sapiens)
Explore O75460 
Go to UniProtKB:  O75460
PHAROS:  O75460
GTEx:  ENSG00000178607 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO75460
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.00 Å
  • R-Value Free:  0.281 (Depositor), 0.280 (DCC) 
  • R-Value Work:  0.231 (Depositor), 0.231 (DCC) 
  • R-Value Observed: 0.234 (Depositor) 
Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.18α = 74.61
b = 77.5β = 78.09
c = 141.06γ = 65.63
Software Package:
Software NamePurpose
PHENIXrefinement
XSCALEdata scaling
XDSdata reduction
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Max Planck SocietyGermanyCGCIII_2018_Wu

Revision History  (Full details and data files)

  • Version 1.0: 2025-09-17
    Type: Initial release
  • Version 1.1: 2026-01-21
    Changes: Database references