The role of caspases in MST3-induced cell apoptosis

• Main Authors: Lee Wan Shu, 李韻舒
• Other Authors: Yuan Chiun Jye
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/02813708098713678818

碩士 === 國立交通大學 === 生物科技研究所 === 91 === Mst 3 (Mammalian Ste20-like protein kinase 3), a 52 kDa protein, plays an important role in the process of cell apoptosis. It is a member of human Ste20 like protein kinase family containing a kinase domain at its N-terminus and a regulatory domain at C-terminus. Previous studies have shown that Mst3 is existed in the cytoplasm and can be activated by caspases. Interestingly, the truncation of Mst3 induced a nucleus translocation of itself. Preliminary studies have found that Mst3 contained a NLS (nuclear localization signal) domain located prior to the caspases cleavage site. Upon sequence alignment several NES (nuclear exporting signal) domain were postulated. Overexpression of various deletion mutants of Mst3 demonstrated that Mst3 (335-416) may contain two NES domains at regions between amino acid 336-346 and 385-395. Previous studies have shown that overexpression of Mst3WT and MstWTΔ314 could induce cell apoptosis. Interestingly, we found that Mst3 might mediate cell apoptosis through a caspase-independent manner. Mst3-induced cell aoptosis could not be inhibited by a broad-caspase inhibitor, zVAN-fmk nor facilitated by the coexpression of procaspase-3. The molecular mechanism of Mst3-mediated cell apoptosis remains to be studied.