Fig. 8. Vid22p is targeted to the plasma membrane independent of the secretory pathway. (A) The sec18-1 mutant strain expressing Vid22p-V5 was radiolabeled for 20 minutes at 37°C and chased for 0, 30 and 60 minutes at 22°C or 37°C. Total lysates were immunoprecipitated with anti-V5 antibodies or anti-CPY antibodies. Immunoprecipitated materials were resolved by SDS-PAGE and radiolabeled proteins were visualized using a phosphorimager. (B) Wild-type cells expressing Vid22p-V5 were labeled for 20 minutes and chased for 0, 30 and 60 minutes at 30°C. Cells were lysed and subjected to differential centrifugation as described in the Materials and Methods section. Each fraction was detergent solubilized and immunoprecipitated with an anti-V5 antibody. The precipitated proteins were solubilized in SDS sample buffer and resolved by SDS-PAGE. Radiolabeled Vid22p was visualized by phosphorimager analysis.