FIG. 4.

Ctk2p turnover in cells that have impaired catalytic proteasome subunits. WCG4a (wild type [WT]; A) and isogenic WCG4-11/22a (pre1 pre2; B and C) cells transformed with the CTK2-HA construct were grown in SD medium to an OD₆₀₀ of 0.8. For panels A and B, cultures were then shifted to the nonpermissive temperature (37°C) for 40 min prior to the addition of cycloheximide, and aliquots were taken at different times (minutes) of incubation at 37°C. (C) Cultures were shifted to the nonpermissive temperature for 1 or 3 h. Resulting cellular extracts were analyzed by Western immunoblotting.