Figure 9.

HtrA4 promotes degradation of XIAP and, less efficiently, of β-tubulin, actin, and pro-caspase 7. The A549 cells with exogenous HtrA4, ΔN-HtrA4, or their inactive variants (+) induced by adding doxycycline to the medium were treated with 15 µM etoposide for 48 h. Control cells (−) were incubated with etoposide but without doxycycline. The cells and medium were collected and probed with specific antibodies. Representative blots are presented. Densitometric analyses of the immunoblotting results are shown in Figure S5.