Distinct cleavage pattern of caspase substrates in apoptosis

다국어 초록 (Multilingual Abstract)

We have developed a novel in vitro screening strategy to systemically identify caspase substrates. By screening human brain and mouse thymus library, we have identified new putative caspase substrate clones. Tau, a microtubule associated protein, and IkBα, an inhibitory component of NF-kB transcription factor, were cleaved in vitro by caspase-3 but not by caspase-8 or -9. When cortical neuronal cells were treated with staurosporin, Tau was cleaved into the truncated form. The cleavage was inhibited by z-VAD, a caspase inhibitor, suggesting that Tau is cleaved in the cells undergoing apoptosis. A possibility for phosphorylation-dependent cleavage by caspase will be discussed.