HeLa细胞中与组织型转谷氨酰胺酶相互作用蛋白质的筛选

组织型转谷氨酰胺酶 (tissuetransglutaminase ,tTG ,TGII)是转谷氨酰胺酶家族成员之一 ,多数细胞凋亡过程中均有tTG表达水平的升高。为研究tTG在细胞凋亡过程中发挥作用的机制 ,利用Gal 4酵母双杂交系统筛选了HeLa细胞中与tTG相互作用的蛋白质 ,获得了 17个阳性酵母克隆。序列测定显示其中 1个克隆所含cDNA序列编码TIA 1相关蛋白 (TIA 1 relatedprotein ,TIAR )C端 12 9个氨基酸残基序列 ,GST下拉 (pull down)实验也证实tTG与TIAR能相互作用 ,而且这种相互作用需要Ca2 参与作用。这些结果提示tTG可能通过其Ca2 依赖的转谷氨酰胺活性对TIAR进行修饰从而影响TIAR的功能 ,可能在细胞凋亡中发挥着一定的作用。

Screening of Proteins Interacting with tTG in HeLa Cells

Tissue transglutaminase(tTG) belongs to a class of transglutaminase family which is up- regulated in almost all cells apoptosis and is thought to be closely related to cell apoptosis. To investigate the mechanism of tTG in cell apoptosis, yeast two hybrid system was used to screen HeLa cDNA library. One of the 17 positive clones we have obtained encoded the glutamine-rich carboxyl terminus of TIAR, and this interaction between tTG and TIAR, which was finely regulated by Ca 2 , was proved in vitro by GST pull-down. These findings suggest that tTG might affect the function of TIAR by a calcium- dependent posttranslational modification and the interaction might possibly be involved in the regulation of cell apoptosis.