Figure 1.

dsl1-7 shows a CPY trafficking block in the absence of an invertase block. Log phase wild-type (RSY255), dsl1-4 (GWY230), and dsl1-7 (GWY233) strains were grown on media lacking methionine and containing 2% raffinose and 0.1% glucose for 1 h before a shift to the indicated temperature for 20 min. Strains were labeled with ³⁵S-amino acids for 10 min, chased for 20 min at the same temperature, and lysed. CPY (top) or invertase (bottom) was then immunoprecipitated from each sample, separated by SDS-7% PAGE, and visualized by autoradiography. The migration of the pre-Golgi (p1), Golgi (p2), and mature (m) forms of CPY, and of the ER and Golgi forms of invertase is indicated on the right. Immunoprecipitations from lysates of sec17-1 (GWY270) and pep4Δ (MS1554) strains incubated at 37°C were used as controls for the p1 and p2 forms of CPY, and the ER and mature form of invertase, respectively. INV, invertase; IP, immunoprecipitation.