Figure 8.

Degradation of Ste6–166p requires the activity of the 20S proteasome. The metabolic stability of Ste6–166p was examined by pulse-chase analysis as described in Figure 4. (A) The labeling of the pre1–1 pre2–1 mutant and the isogenic wild-type strains was performed after a 40-min preincubation at 37°C. Strains were SM3289 (wild-type [CEN ste6–166::HAe]) and SM3291 (pre1–1 pre2–1 [CEN ste6–166::HAe]). (B) To assess the effect of the proteasome inhibitor MG132 on the degradation of Ste6–166p, cells were pretreated with 50 μM MG123 in DMSO or DMSO only for 1 h before labeling. The strain used was SM3599 (erg6Δ [CEN ste6–166::HAe]).