Linear ubiquitination is involved in the pathogenesis of optineurin-associated amyotrophic lateral sclerosisNakazawa, S., Oikawa, D., Ishii, R., Ayaki, T., Takahashi, H., Takeda, H., Ishitani, R., Kamei, K., Takeyoshi, I., Kawakami, H., Iwai, K., Hatada, I., Sawasaki, T., Ito, H., Nureki, O., Tokunaga, F.
(2016) Nat Commun 7: 12547-12547
- PubMed: 27552911
- DOI: https://doi.org/10.1038/ncomms12547
- Primary Citation of Related Structures:
- PubMed Abstract:
Optineurin (OPTN) mutations cause neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and glaucoma. Although the ALS-associated E478G mutation in the UBAN domain of OPTN reportedly abolishes its NF-κB suppressive activity, the precise molecular basis in ALS pathogenesis still remains unclear. Here we report that the OPTN-UBAN domain is crucial for NF-κB suppression. Our crystal structure analysis reveals that OPTN-UBAN binds linear ubiquitin with homology to NEMO. TNF-α-mediated NF-κB activation is enhanced in OPTN-knockout cells, through increased ubiquitination and association of TNF receptor (TNFR) complex I components. Furthermore, OPTN binds caspase 8, and OPTN deficiency accelerates TNF-α-induced apoptosis by enhancing complex II formation. Immunohistochemical analyses of motor neurons from OPTN-associated ALS patients reveal that linear ubiquitin and activated NF-κB are partially co-localized with cytoplasmic inclusions, and that activation of caspases is elevated. Taken together, OPTN regulates both NF-κB activation and apoptosis via linear ubiquitin binding, and the loss of this ability may lead to ALS.
Laboratory of Molecular Cell Biology, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma 371-8512, Japan.