FIGURE 6:

ER–Golgi and intra-Golgi traffic are delayed in the swa2Δ mutant. (A) CPY processing: wild type (SFNY1842; lanes 1–6) and the swa2Δ mutant (SFNY2683; lanes 7–12) were shifted to 15°C for 60 min, pulse labeled for 10 min, and chased for the indicated times. CPY was immunoprecipitated from lysates and processed as described in Materials and Methods. The p1 (67 kDa), p2 (69 kDa), and mature (m; 61 kDa) forms of CPY are indicated. (B) Quantification of the ratio of p2CPY/p1CPY from three independent experiments. Error bars represent SD. *, p < 0.05, Student’s t test. (C) Invertase processing and transport: wild-type and swa2∆ cells were shifted to 15°C for 1 h and then incubated at the same temperature for 30 min in low-glucose medium (to induce extracellular invertase expression) in the presence of [³⁵S]ProMix. The cells were converted to spheroplasts and pelleted. Then invertase was immunoprecipitated from the cell pellet fraction (Internal; lanes 1–3) and spheroplast supernatant fractions (External; lanes 4 and 5). Cytoplasmic invertase, glycosylated ER, and Golgi forms of invertase are indicated. Lane 3, a darker exposure of sample shown in lane 2.