Figure 2.

Overproduction of Vam3p specifically suppresses the ALP processing defect in vti1-2 cells. The t-SNAREs Vam3p (vacuole), Pep12p (PVC), or Sed5p (cis-Golgi) were overproduced in vti1-2 cells by introducing multicopy plasmids encoding these proteins. ALP transport was compared with vti1-2 cells without a multicopy plasmid (−). Cells were preincubated for 15 min and labeled for 7 min at 36°C. Aliquots were removed after 0-, 10-, 20-, and 30-min chase periods. ALP was immunoprecipitated and analyzed by SDS-PAGE. Overproduction of Vam3p resulted in the appearance of vacuolar ALP (mALP), indicating that VAM3 overexpression suppressed the ALP traffic defect in vti1-2 cells. By contrast, overproduction of Pep12p and Sed5p had no effect on ALP processing.