PI31 is a positive regulator of 20S immunoproteasome assembly.

ABSTRACT: Proteasome inhibitor of 31,000 Da (PI31) is a 20S proteasome-binding protein originally identified as an inhibitor of in vitro 20S proteasome activity. Although recent studies have elucidated a detailed structural basis for this inhibitory activity, the physiological significance of PI31-mediated proteasome inhibition remains uncertain, and multiple alternative cellular roles for PI31 have been described. Here, we report a role for PI31 as a positive regulator for assembly of the 20S immunoproteasome (20Si), a compositionally and functionally distinct isoform of the proteasome that is poorly inhibited by PI31. Genetic ablation of PI31 in mammalian cells had no effect on the cellular content or activity of constitutively expressed proteasomes but reduced the cellular content and activity of

SUBMITTER: Wang J 

PROVIDER: S-EPMC12148024 | biostudies-literature | 2025 May

REPOSITORIES: biostudies-literature