PI31 is a positive regulator of 20S immunoproteasome assembly.

ABSTRACT: PI31 (Proteasome Inhibitor of 31,000 Da) is a 20S proteasome-binding protein originally identified as an inhibitor of in vitro 20S proteasome activity. Although recent studies have provided a detailed structural basis for this activity, the physiologic significance of PI31-mediated proteasome inhibition remains uncertain and alternative cellular roles for PI31 have been described. Here we report a role for PI31 as a positive regulator for the assembly of the 20S immuno-proteasome (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 interferon-γ-

SUBMITTER: Wang J 

PROVIDER: S-EPMC11761684 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature