Identification and Analysis of Subcellular Localization Signal of Caspase-3

Caspase-3 is a key mediator of apoptosis.During apoptosis,caspase-3 is cleaved and activated by the protease,and enters into the nucleus,resulting in biochemical and morphological changes in apoptosis.However,the molecular mechanism of nucleus-entering of active caspase-3 is still unknown.Identifying the subcellular localization of caspase-3 molecule is important for understanding the process.In this study,we constructed various truncated caspase-3 mutant constructs that were fused with GFP,observed the cellular localization of these mutant proteins,and determined the subcellular localization of caspase-3 molecule.The results show that caspase-3 lacks obvious nuclear localization signal(NLS),but bears an obvious nuclear export signal(NES),which is located at the C-terminus of its small subunit including residues 220～245.