Visualizing chaperone-mediated multistep assembly of the human 20S proteasome.

ABSTRACT: Dedicated assembly factors orchestrate the stepwise production of many molecular machines, including the 28-subunit proteasome core particle (CP) that mediates protein degradation. Here we report cryo-electron microscopy reconstructions of seven recombinant human subcomplexes that visualize all five chaperones and the three active site propeptides across a wide swath of the assembly pathway. Comparison of these chaperone-bound intermediates and a matching mature CP reveals molecular mechanisms determining the order of successive subunit additions, as well as how proteasome subcomplexes and assembly factors structurally adapt upon progressive subunit incorporation to stabilize intermediates, facilitate the formation of subsequent intermediates and ultimately rearrange to coordinate proteoly

SUBMITTER: Adolf F 

PROVIDER: S-EPMC11327110 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature