iScience
Volume 24, Issue 7, 23 July 2021, 102733
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Article
The optineurin/TIA1 pathway inhibits aberrant stress granule formation and reduces ubiquitinated TDP-43

https://doi.org/10.1016/j.isci.2021.102733Get rights and content
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Highlights

  • ALS-linked mutations of optineurin (OPTN) delay clearance of stress granules (SGs).

  • Depletion of OPTN increases ubiquitinated TDP-43 levels by increasing TIA1

  • ALS-linked OPTN mutants increase ubiquitinated TDP-43 levels by increasing TIA1

  • High TIA1 induces aberrant SGs with ubiquitinated TDP-43 and delays SG clearance

Summary

Amyotrophic lateral sclerosis (ALS) is a degenerative motor neuron disease characterized by the formation of cytoplasmic ubiquitinated TDP-43 protein aggregates in motor neurons. Stress granules (SGs) are stress-induced cytoplasmic protein aggregates containing various neuropathogenic proteins, including TDP-43. Several studies have suggested that SGs are the initial site of the formation of pathogenic ubiquitinated TDP-43 aggregates in ALS neurons. Mutations in the optineurin (OPTN) and TIA1 genes are causative factors of familial ALS with TDP-43 aggregation pathology. We found that both OPTN depletion and ALS-associated OPTN mutations upregulated the TIA1 level in cells recovered from heat shock, and this upregulated TIA1 increased the amount of ubiquitinated TDP-43. Ubiquitinated TDP-43 induced by OPTN depletion was localized in SGs. Our study suggests that ALS-associated loss-of-function mutants of OPTN increase the amount of ubiquitinated TDP-43 in neurons by increasing the expression of TIA1, thereby promoting the aggregation of ubiquitinated TDP-43.

Subject areas

Biological sciences
Molecular neuroscience
Cellular neuroscience

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