Dynamic JUNQ inclusion bodies are asymmetrically inherited in mammalian cell lines through the asymmetric partitioning of vimentin

We show, for the first time to our knowledge, that vimentin intermediate filaments establish mitotic polarity in dividing mammalian cell lines. By confining damaged, misfolded, and aggregated proteins in JUNQ inclusion bodies, vimentin mediates their asymmetric partitioning during division. We also, to our knowledge, provide the first direct evidence of active proteasomal degradation in dynamic JUNQ inclusion bodies. This work sheds light on an important rejuvenation mechanism in mammalian cells and provides new biological insight into the role of inclusion bodies in regulating aggregation, toxicity, and aging.