Jeong Eui Man, Kim Chai-Wan, Cho Sung-Yup, Jang Gi-Yong, Shin Dong-Myung, Jeon Ju-Hong, Kim In-Gyu
Department of Biochemistry and Molecular Biology/Aging and Apoptosis Research Center (AARC), Seoul National University College of Medicine, 28 Yongon Dong, Chongno Gu, Seoul 110-799, Republic of Korea.
FEBS Lett. 2009 Feb 18;583(4):648-54. doi: 10.1016/j.febslet.2009.01.032. Epub 2009 Feb 1.
Transglutaminase 2 (TG2) is a calcium-dependent enzyme that catalyzes the transamidation reaction. There is conflicting evidence on the role of TG2 in apoptosis. In this report, we show that TG2 increases in response to low level of oxidative stress, whereas TG2 diminishes under high stress conditions. Monitoring TG2 expression, activity and calcium concentration in cells treated with A23187 revealed that the initial rise of calcium activates TG2 but subsequent calcium-overload induces the degradation of TG2 via calcium-mediated polyubiquitination. These results indicate that the role of TG2 in apoptosis depends on the level of calcium influx triggered by oxidative stress.
转谷氨酰胺酶2（TG2）是一种催化转酰胺反应的钙依赖性酶。关于TG2在细胞凋亡中的作用，存在相互矛盾的证据。在本报告中，我们表明，TG2会随着低水平氧化应激而增加，而在高应激条件下则会减少。监测用A23187处理的细胞中TG2的表达、活性和钙浓度发现，钙的初始升高会激活TG2，但随后的钙超载会通过钙介导的多聚泛素化诱导TG2降解。这些结果表明，TG2在细胞凋亡中的作用取决于氧化应激引发的钙内流水平。
