Fig. 7.

Knockdown of MK-STYX protects against BH3-only-induced apoptosis. (A) HeLa cells were transfected with control or MK-STYX siRNA for 48 h before transfection with vector, Bax, tBid, or BimS cDNA. Twenty-four hours after transfection, crystal violet was used to stain only viable cells. (B) The cell lysates detailed in panel A were collected and immunoblotted for expression levels of each overexpressed protein; tubulin served as a loading control. (C) GFP-tagged tBid was transfected into control and MK-STYX knockdown HeLa cells for 24 h. Cytochrome c was visualized by immunofluorescence (red); loss of punctate cytochrome c staining is indicated by the arrows. (D) Cells transfected with siRNAs and the indicated cDNAs were assayed for apoptosis through TUNEL positivity. The error bars indicate standard deviations.