1. γ-Glutamyltranspeptidase of Helicobacter pylori induces mitochondria-mediated apoptosis in AGS cells
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Kim, Kyung-Mi, Lee, Seung-Gyu, Park, Min-Gyu, Song, Jea-Young, Kang, Hyung-Lyun, Lee, Woo-Kon, Cho, Myung-Je, Rhee, Kwang-Ho, Youn, Hee-Shang, and Baik, Seung-Chul
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HELICOBACTER pylori , *NUCLEOTIDE sequence , *APOPTOSIS , *RECOMBINANT DNA - Abstract
Abstract: γ-Glutamyltranspeptidase (GGT) is a novel protein involved in the induction of Helicobacter pylori-mediated apoptosis; however, the signal pathway involved in GGT-induced apoptosis remains unclear. Using DNA recombination techniques, ggt was cloned into pET117b and transformed into Escherichia coli. Recombinant GGT was purified using nickel-affinity resin and was digested by thrombin. Recombinant GGT induced apoptosis in AGS cells in a time-dependent manner, which was confirmed by TUNEL staining, the MTT assay and immunoblot analysis for caspases-9, -3, Bax, Bcl-2, Bcl-xL and cytochrome c release. Activation of caspase-3 and -9 following exposure to GGT increased in a time-dependent manner and upregulation of proapoptotic Bax and a downregulation of antiapoptotic Bcl-2 and Bcl-xL was detected. Apoptotic signals also trigger changes in mitochondria, which lead to a release of cytochrome c into the cytosolic space. The GGT-deficient mutant was not as able to induce apoptosis as the wild-type strain. These results indicate that GGT of H. pylori induces apoptosis via a mitochondria-mediated pathway. [Copyright &y& Elsevier]
- Published
- 2007
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