Abstract

X-linked inhibitor of apoptosis protein (XIAP) deficiency causes refractory inflammatory bowel disease. The XIAP protein plays a pivotal role in the pro-inflammatory response through the nucleotide-binding oligomerization domain-containing signaling pathway that is important in mucosal homeostasis. We analyzed the molecular mechanism of non-synonymous pathogenic variants (PVs) of XIAP BIR2 domain. We generated N-terminally green fluorescent protein-tagged XIAP constructs of representative non-synonymous PVs. Co-immunoprecipitation and fluorescence cross-correlation spectroscopy showed that wild-type XIAP and RIP2 preferentially interacted in live cells, whereas all non-synonymous PV XIAPs failed to interact properly with RIP2. Structural analysis showed that various structural changes by mutations, such as hydrophobic core collapse, Zn-finger loss, and spatial rearrangement, destabilized the two loop structures (174–182 and 205–215) that critically interact with RIP2. Subsequently, it caused a failure of RIP2 ubiquitination and loss of protein deficiency by the auto-ubiquitination of all XIAP mutants. These findings could enhance our understanding of the role of XIAP mutations in XIAP-deficient inflammatory bowel disease and may benefit future therapeutic strategies.

Details

Title
Understanding the molecular mechanism of pathogenic variants of BIR2 domain in XIAP-deficient inflammatory bowel disease
Author
Lee, Juhwan 1 ; Sim, Kyoung Mi 2 ; Kang, Mooseok 3 ; Oh, Hyun Ju 4 ; Choi, Ho Jung 4 ; Kim, Yeong Eun 4 ; Pack, Chan-Gi 2 ; Kim, Kyunggon 2 ; Kim, Kyung Mo 4 ; Oh, Seak Hee 4 ; Kim, Inki 5 ; Chang, Iksoo 6 

 iProtein Therapeutics Inc., Daejeon, Korea 
 University of Ulsan College of Medicine, Department of Convergence Medicine, Asan Medical Center, Asan Institutes for Life Sciences, Seoul, Korea (GRID:grid.267370.7) (ISNI:0000 0004 0533 4667) 
 iProtein Therapeutics Inc., Daejeon, Korea (GRID:grid.267370.7) 
 University of Ulsan College of Medicine, Department of Pediatrics, Asan Medical Center Children’s Hospital, Seoul, Korea (GRID:grid.267370.7) (ISNI:0000 0004 0533 4667) 
 University of Ulsan College of Medicine, Department of Convergence Medicine, Asan Medical Center, Asan Institutes for Life Sciences, Seoul, Korea (GRID:grid.267370.7) (ISNI:0000 0004 0533 4667); University of Ulsan College of Medicine, Department of Pharmacology, Seoul, Korea (GRID:grid.267370.7) (ISNI:0000 0004 0533 4667) 
 DGIST, Creative Research Initiatives Center for Proteome Biophysics, Department of Brain Sciences and Supercomputing Bigdata Center, Daegu, Korea (GRID:grid.417736.0) (ISNI:0000 0004 0438 6721); DGIST, Department of Brain Sciences and Supercomputing Big Data Center, Daegu, Korea (GRID:grid.417736.0) (ISNI:0000 0004 0438 6721) 
Pages
853
Publication year
2024
Publication date
2024
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2911679929
Copyright
© The Author(s) 2024. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.