FIGURE 4:

The chaperone-like activity and the oxidoreductase activity of Pdi1 respectively facilitate the ERAD of ApoB29 and CPY*. Cycloheximide chase reactions were performed as described in Materials and Methods in pdi1Δ [PDI1_CGHC-CGHC] (●), pdi1Δ [PDI1_SGHS-CGHC] (○), or pdi1Δ [PDI1_CGHC-SGHS] (□) yeast strains expressing ApoB29 (A) or CPY* (B). Cycloheximide chase reactions were also performed in pdi1Δ [PDI1_CGHC-CGHC] (●) or pdi1Δ [PDI1_222-302Δ] (○) yeast strains expressing ApoB29 (C). Chase reactions were conducted at 30°C, and lysates were immunoblotted with anti-HA antibody. Anti-Sec61 antiserum was used as a loading control for chase reactions monitoring CPY*, and anti-G6PD antiserum was used as a loading control for chase reactions measuring ApoB29 degradation. Top, quantitative data. Bottom, representative blots. Data represent the means of five to seven experiments, ± SEM. The lack of visible error bars indicates that the SEM is less than the size of the symbol. **p < 0.01.