Figure 3.
The role of Hsp104 in the resumption of the secretion competence of Hsp150Δ-β-lactamase. sec18-1 (A; H393) and Δhsp104 sec18-1 (B; H534) cells were preincubated for 10 min at 37°C, labeled with [35S]methionine/cysteine for 60 min at the same temperature, and incubated for 15 min at 48°C. The labeling medium was replaced by SC medium with excess unlabeled methionine and cysteine, and the cells were shifted to 24°C for the indicated times (lanes 1, 2, and 5–12). In lanes 3 and 4, the 48°C treatment was omitted. In lanes 13 and 14, sodium azide was included in the recovery mixture. The culture medium samples (lanes with uneven numbers) and lysed cell samples (lanes with even numbers) were immunoprecipitated with β-lactamase antiserum and analyzed by SDS-PAGE. Mature (145 kDa) and ER-specific (110 kDa) Hsp150Δ-β-lactamase are indicated.