Both the proteasome 19S regulatory particle and 20S core particle associate with actin filaments.

4 µM yeast actin and either ∼65 nM 19S proteasome regulatory particle (A and B) or 50–100 nM 20S proteasome core particle (C and D) were incubated in G-buffer (A and C) or in F-buffer (C and D), centrifuged at 190,000×g and volume-corrected samples were taken from the supernatant (S) or pellet (P) phases. T are the fractions taken prior to centrifugation. All fractions were separated by SDS-PAGE and stained with SYPRO Ruby (Bio-Rad, Hercules CA).