Molecular and Structural Basis of the Proteasome α Subunit Assembly Mechanism Mediated by the Proteasome-Assembling Chaperone PAC3-PAC4 Heterodimer

The 26S proteasome is critical for the selective degradation of proteins in eukaryotic cells. This enzyme complex is composed of approximately 70 subunits, including the structurally homologous proteins α1–α7, which combine to form heptameric rings. The correct arrangement of these α subunits is essential for the function of the proteasome, but their assembly does not occur autonomously. Assembly of the α subunit is assisted by several...