Figure 4.

Effect of ADAM17-mediated ACE2 shedding on ACE2 protein stability. The 832/13 cells that were cotransfected in four experiments with 100 μg/well mACE2/pcDNA3.1 and 2 μg/well of either pAd17 or pAd17E406A were treated with cycloheximide. The total ACE2 activity (A) and ADAM17 activity (B) were measured for up to 21 hours. Exponential decay curves were fitted to the data between the 0- and 8-hour time points. The ratio of total shed ACE2 to total cellular ACE2 activity was also determined (C). *, ***, P < .05, P < .001 vs pAd17E406A for post hoc contrasts after an ANOVA.