Figure 3.

CPY* degradation is affected only moderately in cells defective in COPI-coated vesicle formation at restrictive temperature. Pulse-chase analysis was performed as described in Figure 1, except that the cells were shifted to restrictive temperature 60 min before the chase. (A) CPY* degradation in isogenic wild-type and sec21-1 mutant strain. (B) CPY* degradation in isogenic wild-type, sec27-1, and sec27-1 Δpep4 mutant strains. (C) Maturation of PrA was measured in a pulse-chase experiment in COPI mutant and isogenic wild-type strains. The experiment was done as described for Figure 3A, except that the cells were labeled with radioactive methionine for 10 min. (D) COPI-coated vesicle transport is affected in the mutant strains under the conditions used. Emp47p degradation was followed in a cycloheximide chase experiment after a 60-min preincubation at 37°C. Equal amounts of cells were taken at the indicated time points. Pgk1p served as a loading control.