Secretion profiles of FV mutants.

COS-1 cells expressing wt-FV or the FV mutants were radiolabeled for 30 minutes (pulse); then, cell lysates and culture media were harvested at the indicated time points (chase). Radiolabeled FV was quantitatively immunoprecipitated and electrophoresed on 7.5% polyacrylamide gels under reducing conditions. Then, the radioactivity of FV-specific bands on the gels was measured. Quantitative results (mean ± SD, n = 3) of wt-FV (○), mutant Q (■), mutant Met385Thr (⋄), mutant His1299Arg (×), mutant Met1736Val (▵), and mutant Asp2194Gly (▿) are shown. The amount of radioactive FV in the cell lysate at 0 hours is assigned to be 100% for each construct.