Figure 5.

Src phosphorylates caspase-7 at multiple tyrosine sites. (a) Potential tyrosine phosphorylation sites of caspase-7 were predicted by the NetPhos 2.0 software program. (b) Peptide mapping of nine synthesized peptides containing potential tyrosine sites. Sites were examined using an in vitro kinase assay with Src in the presence of [γ-³²P] ATP and results were visualized by autoradiography. (c) Confirmation of the peptide mapping results using an in vitro kinase assay with Src and wild-type (Wt)-caspase-7 or mutant (Mut)-caspase-7. Results were visualized by autoradiography. Coomassie Brilliant Blue staining was used to assure that the same quantity of protein was loaded. For b and c, representative blots from three independent experiments are shown