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新近的研究揭示：ｃａｓｐａｓｅ蛋白酶在细胞凋亡中起着死亡执行者的重要功能．一些蛋白相继被证明在细胞凋亡中可被ｃａｓｐａｓｅ特异切割，其中参与ＤＮＡ损伤修复过程的聚ＡＤＰ核糖聚合酶（ＰＡＲＰ）以及ＤＮＡ依赖的蛋白激酶（ＤＮＡ－ＰＫ），在细胞凋亡过程中被ｃａｓｐａｓｅ选择性切割具有特殊的功能意义．为探索与ＤＮＡ－ＰＫ催化亚基有较高同源性，含有ｃａｓｐａｓｅ切割位点，且功能上目前也被认为是感受ＤＮＡ损伤和参与信号传导途径的ＡＴＭ（Ａｔａｘｉａｔｅｌａｎｇ－ｉｅｃｔａｓｉａｍｕｔａｔｅｄ）蛋白，是否在凋亡过程中也可被切割而降解？应用体外转录与翻译系统获得ＡＴＭ蛋白的ＰＩ３Ｋ结构域，同时通过建立无细胞反应体系获得含ｃａｓｐａｓｅ活性的细胞抽提液，将两者在体外共同保温．结果发现：ＡＴＭ蛋白与ｃａｓｐａｓｅ－３能免疫共沉淀，ＡＴＭ蛋白的ＰＩ３Ｋ结构域可被ｃａｓｐａｓｅ－３特异切割，并观察到辐射诱发细胞调亡中ＡＴＭ蛋白的降解．从而进一步证实了ＤＮＡ损伤修复的抑制，促进细胞凋亡的发生．
Recent studies have revealed that caspase plays an important role as a perpetrator of apoptosis in apoptosis. Some proteins have been demonstrated to be cleaved caspase specifically in apoptosis. Among them, poly-ADP ribose polymerase (PARP) and DNA-dependent protein kinase (DNA-PK) are involved in the process of DNA damage repair and are involved in the process of apoptosis Caspase selective cleavage has a special functional significance. To explore whether ATM (Ataxiatelang-iectasiamutated) protein, which has high homology with DNA-PK catalytic subunit, contains caspase cleavage site and is functionally considered to be susceptible to DNA damage and participates in signal transduction pathways, Can also be cut and degraded? The in vitro transcription and translation system was used to obtain the PI3K domain of ATM protein. At the same time, cell-free extracts containing caspase activity were obtained by establishing a cell-free reaction system. Both of them were co-incubated in vitro. The results showed that the ATM protein was co-immunoprecipitated with caspase-3, and the PI3K domain of ATM protein was cleaved by caspase-3, and the degradation of ATM protein in radiation-induced apoptosis was observed. Which further confirmed the inhibition of DNA damage repair and promote the occurrence of apoptosis.