A functional interaction between TDP-43 and USP10 reveals USP10 dysfunction in TDP-43 proteinopathies

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterised by the progressive degeneration of motor neurons in the cerebral cortex and spinal cord, with a rapid progression from diagnosis to death. The great majority of ALS cases and around 50% of FTD cases present with TDP-43 pathology, leading to mislocalization and cytoplasmic aggregation of TDP-43, which can result in both its loss of nuclear functions and a gain of toxicity in the cytoplasm. TDP-43 and other RNA-binding proteins accumulate in stress granules (SGs) under stress conditions. The ubiquitin-specific protease 10 (USP10) is an inhibitor of SGs assembly that has been recently linked to neurodegeneration. Here, we identified a new functional interaction between TDP-43 and USP10, in which USP10 can control multiple aspects of TDP-43 biology that are thought to play important roles in its involvement in disease pathogenesis, such as its cytoplasmic and nuclear aggregation, expression and splicing functionality. In turn, TDP-43 is also able to control diverse aspects of USP10 biology, such as its expression levels, aggregation and function. Critically, we found USP10 dysregulation in ALS and FTD patients, overall suggesting a possible role for USP10 in ALS/FTD pathogenesis. ### Competing Interest Statement The authors have declared no competing interest.