| Cleavage of claspin by caspase 7 during apoptosis inhibits the Chk 1 pathway . ^^^ Here , we show that human Claspin is cleaved by caspase 7 during the initiation of apoptosis . ^^^ Subsequently , etoposide caused activation of caspase 7 , cleavage of Claspin , and dephosphorylation of Chk 1 . ^^^ In apoptotic cell extracts , Claspin was cleaved by caspase 7 at a single aspartate residue into a large N terminal fragment and a smaller C terminal fragment that contain different functional domains . ^^^ These results indicate that cleavage of Claspin by caspase 7 inactivates the Chk 1 signaling pathway . ^^^ |