Figure 2.

A proprotein convertase inhibitor increases surface expression and cellular levels of immature ADAM10. A. HEK-M3 cells were transiently transfected with ADAM10. After 48 h, cells were pre-treated with DMSO or the proprotein convertase inhibitor, dec-RVKR-CMK, for 2 h. Cells were surface-biotinylated and lysed. Biotinylated proteins and cell lysates were immunoblotted with antibodies to ADAM10. Levels of biotinylated immature ADAM10 were quantitated and expressed as means ± SEM from five experiments. *Significantly different from control group. B. Cells co-transfected with ADAM10 and APP₆₉₅ were treated with DMSO or dec-RVKR-CMK for 2 h. Fresh serum-free medium with DMSO or dec-RVKR-CMK was then placed on the cells and the medium was collected 2 h later. Medium extracts were immunoblotted with 6E10 antibodies, and lysates with antibodies to the APP C-terminus. Levels of sAPPα₆₉₅ in the medium were quantitated, normalized to control values, and expressed as means ± SEM from 5 experiments. *Significantly different from control values.