FIGURE 4.

Rab17 sumoylation is a reversible modification and its levels are specifically maintained. A, WIF-B cells were infected for the indicated times with recombinant adenovirus expressing FLAG-tagged rab17. Lysates were collected and immunoblotted for rab17 using anti-FLAG antibodies. The relative levels of the 25- and 40-kDa bands were determined by densitometry and the arbitrary units (a.u.) plotted (B). In C, the percent of total rab17 detected as the 40-kDa species for each time was determined and plotted. B and C are representative of at least three independent experiments. D, WIF-B cells expressing myc-tagged wild type rab17 were treated for the indicated times with 50 μg/ml of cycloheximide (CHX). Lysates were prepared and immunoblotted for rab17 using anti-rab17 antibodies. The relative levels of the 25- and 40-kDa bands were determined by densitometry, the values plotted as the percent present at 0 min (E). In F, the percent of total rab17 detected as the 40-kDa species for each time was determined. The values in E and F represent the average from at least 3 independent experiments ± S.E.