期刊
MOLECULAR AND CELLULAR NEUROSCIENCE
卷 108, 期 -, 页码 -出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.mcn.2020.103539
关键词
ALS-FTLD; p62/SQSTM1; TBK1; Autophagy; Mitophagy; Cell signalling
资金
- NHMRC-ARC Dementia Research Development Fellowship Grant [AP1102977]
- Dementia Australia Research Foundation project grant
- Australian Government Research Training Program (RTS) Scholarship
Mutations affecting SQSTMI coding for p62 and TANK-Binding Kinase 1 (TBK1) have been implicated in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). TBK1 is a serine-threonine kinase that regulates p62's activity as an autophagy receptor via phosphorylation and also has roles in neu-roinflammatory signalling pathways. The mechanisms underlying ALS and FTLD pathogenesis as a result of TBK1 mutations are incompletely understood, however, loss of TBK1 function can lead to dysregulated autophagy and mitophagy. Here, we report that an ALS-associated TBK1 variant affecting the kinase domain, p.G175S, is defective in phosphorylation of p62 at Ser-403, a modification critical for regulating its ubiquitin-binding function, as well as downstream phosphorylation at Ser-349. Consistent with these findings, expression of p.G175S TBK1 was associated with decreased induction of autophagy compared to wild type and reduced degradation of the ALS-linked protein TDP-43. Expression of wild type TBK1 increased NF-KB signalling similar to 300 fold in comparison to empty vector cells, whereas p.G175S TBK1 was unable to promote NF-KB signalling above levels observed in empty vector transfected cells. We also noted a hitherto unknown role for TBK1 as a suppressor of oxidative stress (Nrf2) signalling and show that p.G175S TBK1 expressing cells lose this inhibitory function. Our data suggest that TBK1 ALS mutations may broadly impair p62-mediated cell signalling, which ultimately may reduce neuronal survival, in addition TDP-43 was not efficiently degraded, together these effects may contribute to TBK1 mutation associated ALS and FTLD pathogenesis.
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