Figure 1.

Effect of GA25 on the degradation of the Ub-X-GFP reporters. (A) GAr polypeptides of 25 and 239 amino acids were inserted at the C terminus of GFP reporters that had been targeted for ubiquitin-proteasome-dependent degradation by insertion of N end rule or UFD degradation signals. (B Upper) Lysates of HeLa cells transfected with the Ub-M-GFP, Ub-P-GFP, Ub^G76V-GFP, and Ub-R-GFP plasmids and their GA25-containing counterparts were analyzed in Western blots with a polyclonal anti-GFP antibody. The transfected cells were preincubated for 10 h without (−) or with (+) the proteasome inhibitor Z-L₃-VS (10 μM). Molecular mass markers are indicated on the left. (B Lower) Densitometric analysis of the Western blot is presented (AU, arbitrary units).