Sodium arsenite induces aggresome formation by promoting PICK1 BAR domain homodimer formation

The aggresome is a perinuclear structure that sequesters misfolded proteins. It is implicated in various neurodegenerative diseases. The perinuclear structure enriched with protein interacting with C kinase 1 (PICK1) was found to be inducible by cellular stressors, colocalizing with microtubule-organizing center markers and ubiquitin, hence classifying it as an aggresome. Sodium arsenite but not arsenate was found to potently induce aggresome formation through an integrated stress response-independent pathway. In HEK293T cells, under arsenite stress, PICK1 localization to the aggresome was prioritized, and formation of PICK1 homodimers was favored. Additionally, PICK1 could enhance protein entry into aggresomes. This study shows that arsenite can induce the formation of both RNA stress granules and aggresomes at the same time, and that PICK1 shows conditional localization to aggresomes, suggesting a possible involvement of PICK1 in neurodegenerative diseases.