FIG. 5.

Effect of FMK024 on VSGΔgpi degradation. Transgenic cell lines stably expressing 117Δgpi (A) or 221Δgpi (B) were pretreated for 1 h in the presence or absence of the proteasomal inhibitor lactacystin (1 μM) or the cysteine protease inhibitor FMK024 (117Δgpi, 2 μM; 221Δgpi, 20 μM). Cells were then radiolabeled (10-min pulse, 4-h chase) in the continued presence or absence of inhibitor. At the indicated chase times, aliquots (5 × 10⁶ cell equivalents) were removed and 117Δgpi (A) or 221Δgpi (B) was immunoprecipitated from cell (c) and medium (m) fractions. Samples were analyzed by SDS-PAGE and fluorography.