Binding was likely mediated through F-box protein, beta-transducin repeat-containing protein (beta-TrCP), which binds to the first 38 amino acids of pro-caspase-3.
Beta-TrCP1 expression significantly shortened the protein half-life of pro-caspase-3, whereas expression of a dominant-negative beta-TrCP1 mutant with the F-box domain deleted extended it.