FIG. 3.

Vpu accelerates the turnover of mature endogenous BST-2 in CEMx174 cells. (A) CEMx174 cells were infected with equal reverse transcriptase (RT) units of wt NL4-3 and NL4-3/Udel virus stocks produced in 293T cells. Virus replication was monitored by measuring the virus-associated reverse transcriptase activity in culture supernatants as described previously (44). (B) On day 5 after infection cells were pulse-labeled for 1 h at 37°C by the addition of ³⁵S-labeled amino acids and chased for the indicated time intervals in complete medium. BST-2 was immunoprecipitated with specific antibodies. A representative experiment is shown. Mature BST-2 and high-mannose BST-2 are indicated. The position of molecular weight standards is shown on the left. (C) The percentage of BST-2 remaining at each time point was calculated relative to the signal at time zero. (D and E) Total levels of BST-2 were calculated by adding both immature BST-2 (D) and mature BST-2 (E). Plotted data are derived from three independent experiments. Error bars represent standard errors of the means.