FIG. 3.

Genotoxins induce the cleavage of MEKK1. HEK293 cells were either left untreated, stimulated with UV at 100 J/m², or incubated with 50 μM cisplatin, 100 μM etoposide, or 30 μM mitomycin in DMEM containing 0.1% fetal bovine serum. After 18 h, the cells were lysed and subjected to Western blot analysis with antibody 96-001. For clarity, only the unphosphorylated and gel-shifted full-length MEKK1 proteins and the NH₂-terminal MEKK1-derived fragment (fragment B) are shown.