USP10 Inhibits Aberrant Cytoplasmic Aggregation of TDP-43 by Promoting Stress Granule Clearance

TAR DNA-binding protein 43 (TDP-43) is a causative factor of amyotrophic lateral sclerosis (ALS). Cytoplasmic TDP-43 aggregates in neurons are a hallmark pathology of ALS. TAR DNA-binding protein 43 (TDP-43) is a causative factor of amyotrophic lateral sclerosis (ALS). Cytoplasmic TDP-43 aggregates in neurons are a hallmark pathology of ALS. Under various stress conditions, TDP-43 localizes sequentially to two cytoplasmic protein aggregates, namely, stress granules (SGs) first and then aggresomes. Accumulating evidence suggests that delayed clearance of TDP-43-positive SGs is associated with pathological TDP-43 aggregates in ALS. We found that ubiquitin-specific protease 10 (USP10) promotes the clearance of TDP-43-positive SGs in cells treated with proteasome inhibitor, thereby promoting the formation of TDP-43-positive aggresomes, and the depletion of USP10 increases the amount of insoluble TDP-35, a cleaved product of TDP-43, in the cytoplasm. TDP-35 interacted with USP10 in an RNA-binding-dependent manner; however, impaired RNA binding of TDP-35 reduced the localization in SGs and aggresomes and induced USP10-negative TDP-35 aggregates. Immunohistochemistry showed that most of the cytoplasmic TDP-43/TDP-35 aggregates in the neurons of ALS patients were USP10 negative. Our findings suggest that USP10 inhibits aberrant aggregation of TDP-43/TDP-35 in the cytoplasm of neuronal cells by promoting the clearance of TDP-43/TDP-35-positive SGs and facilitating the formation of TDP-43/TDP-35-positive aggresomes.

Automated summary

TDP-43 is a causative factor of ALS, and cytoplasmic TDP-43 aggregates are a characteristic pathology of the disease. USP10 promotes the clearance of TDP-43-positive stress granules (SGs), leading to the formation of TDP-43-positive aggregates. The interaction between TDP-35 and USP10 is RNA-binding-dependent, and impaired RNA binding of TDP-35 results in the formation of USP10-negative aggregates.