Year: 2025
Type: article
Abstract: 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-induced immuno-proteasomes. This selective effect is a consequence of defective 20Si assembly, as indicated by the accumulation of 20Si assembly intermediates. Our results highlight a distinction in the assembly pathways of constitutive and immuno-proteasomes and indicate that PI31 plays a chaperone-like role for the selective assembly of 20S immunoproteasomes.
Source: Journal of Cell Science
DOI: 10.1242/jcs.263887
Authors: Jason Wang, Abbey Kjellgren, George N. DeMartino
Institution: The University of Texas Southwestern Medical Center
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
OpenAlex ID: W4410189694