FIGURE 4.

Involvement of TACE in PMA-stimulated ectodomain cleavage of Ptprz. CHO-WT (wild-type), CHO-M2 (TACE defective), and CHO-(M2+TACE) (M2 cells expressing functional TACE) cells were transiently transfected with the Ptprz-B expression construct. Twenty-four hours after transfection cells were washed and incubated in fresh serum-free medium with or without PMA for 1 h. GM6001 was added 20 min before PMA or vehicle. The cell extracts (left panels) and conditioned media (right panels) were analyzed by Western blotting (WB) with anti-Ptprz-S. The arrows with asterisks indicate immature forms of Ptprz-B accumulated in cells. The designations are shown in Fig. 1, A and E. The figures are representative of three separate experiments, and the results of the densitometric analyses are shown in supplemental Fig. S2.