Figure 6.

The rate of proteasome core particle maturation is unaffected by α1 overexpression. Yeast expressing β5-3xFLAG from the chromosomal locus in a pba3Δ background were transformed with empty vector (EV) or a high-copy plasmid encoding α1. Log phase cells were treated with 250 μg/mL cycloheximide (CHX) to block new protein synthesis and harvested at the indicated times. Cell extracts were separated by SDS-PAGE before immunoblotting with antibodies against FLAG and G6PD (loading control). Bands corresponding to the precursor species (β5_pro-3xFLAG) were normalized to the G6PD loading control. Quantification of the remaining propeptide as a percentage of propeptide present at time = 0 is shown to the right (n = 8; error bars = s.e.m.). Full-length blot is presented in Supplementary Fig. S8.