Figure 6.

Kinetics of stabilization and acquisition of Triton-insolubility. (A) pma1-10 (XGY32) and pma1-10 pep4Δ (XGX28–1A) cells were pulse-labeled for 5 min at 24°C with Expre³⁵S³⁵S and chased at 24°C. At various times of chase, aliquots were removed and either placed on ice with sodium azide or shifted to 37°C for an additional 90-min incubation. Lysates were prepared, and Pma1 was immunoprecipitated and analyzed by SDS/PAGE and fluorography. (B) Lysates from pma1-10 cells (XGY32) pulse-labeled and chased at 24°C were extracted with ice-cold Triton X-100 and separated into Triton-soluble and Triton-insoluble fractions. Pma1 was immunoprecipitated and analyzed by SDS/PAGE and phosphorimaging. Both gel and quantitation are shown. Newly synthesized Pma1-10 is predominantly found in a Triton-insoluble fraction by 15-min chase, whereas resistance to degradation at 37°C is achieved by 1- to 2-h chase.