When proteasome function is impaired, misfolded proteins are partitioned into the JUNQ (juxtanuclear quality control) compartment, which sequesters detergent-soluble proteins, or the IPOD (insoluble protein deposit) compartment. The formation of such inclusions has been viewed as a 'backup' quality control process that occurs when cells fail to refold or degrade proteins. However, by imaging live cells in which proteasomes were not inhibited, Escusa-Toret et al. now show that misfolded proteins are concentrated into inclusions, which they term 'Q-bodies', even as they are degraded by the proteasome.
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