Analysis of the structure and interaction of apoptotic signaling molecules via Fas

死亡效应结构域（DED）是蛋白质相互作用的重要组成部分，参与细胞凋亡信号转导。半胱氨酸蛋白酶caspase-8和病毒蛋白MC 159分别具有两个串联重复的DED。caspase-8的DEDs可诱导细胞凋亡，而MC 159的DEDs则抑制细胞凋亡。为了研究DED结构域的结合和生物活性，我们产生了来自胱天蛋白酶-8和MC 159的DED的缺失和嵌合体突变体。与野生型胱天蛋白酶-8和MC 159相比，这些突变体不起作用。通过在Genbank数据库中搜索含DED蛋白，发现了一个新的分子，其氨基端含有两个串联重复的DED。通过北方印迹分析，我们检测到该分子在小鼠睾丸中的高表达。我们推测该分子可能具有新的信号转导功能。

The death effector domain(DED), which is essential for protein interaction, is involved in apoptotic signal transudation. Cysteine protease caspase-8 and viral protein MC159 have two tandemly repeated DEDs, respectively. The DEDs of caspase-8 could induce apoptosis whereas that of MC159 inhibits apoptosis. To examine binding and biological activities of the DED domains, we generated deletion and chimera mutants of DEDs derived from caspase-8 and MC159. These mutants did not work compare to wild type of caspase-8 and MC159. Therefore, we concluded that the combination of the two-repeated DEDs is necessary for the DED-containing proteins to stimulate or inhibit apoptosis.By searching DED-containing proteins on Genbank database, we found a new molecule which contains two tandemly repeated DEDs at the amino-terminal portion. We detected high expression of this molecules in the mouse testis by northern blot analysis. We suppose that this molecule may have a new function for signal transduction.