Figure EV2. PRN1126 cell permeability and target occupancy of LMP7 or LMP2 in mice.

1. LCL721.174 cells expressing constitutive proteasomes (CP) or LCL721.145 cells expressing immunoproteasomes (IP) were treated with the indicated concentrations of the LMP7 inhibitor PRN1126. The chymotrypsin‐like activity in the cells was determined by the hydrolysis of the cell‐permeable fluorogenic proteasome substrate Meo‐Suc‐GLF‐AMC. Depicted is the mean ± s.d. % of maximal hydrolytic activity of triplicate cultures. The highest fluorescence value was set to 100%.
2. Mice were treated with a single dose of PRN1126 (40 mg/kg, s.c.) or vehicle. Spleens were harvested at the time points indicated, and the drug occupancy of LMP7 or LMP2 subunits was assessed in splenocytes with the ProCISE assay. Data points represent the means ± s.d. of three mice.