凋亡相关因子Livin、Smac及二者关系的研究进展

Study Progress about Apoptosis Related Factors Livin,Smac and their Relationship

Livin是凋亡抑制蛋白（IAPs）家族的新成员，含有一个BIR结构和一个RING结构，BIR结构为Livin抑制细胞凋亡所必需，而RING结构具有E3泛素连接酶活性，Livin具有凋亡抑制作用已经在很多实验观察和临床研究中得到证实，但也有研究发现在效应caspase-3／-7作用下也能生成具有促凋亡作用的tLivin；Smac是一种内源性线粒体促凋亡蛋白，Smae不诱导正常细胞的凋亡，在细胞受凋亡信号刺激后释放到胞质，特异的结合并抑制IAPs对凋亡下游效应caspases的抑制，从而促进细胞凋亡。二者在细胞内相互调控、相互制约。

Livin is a novel inhibitor of apoptosis protein family, which contains a single BIR domain and a RING finger domain. The BIR domain is essential for its activity of anti - apoptosis, and the RING finger domain functions as an E3 ubiquitin ligase. Many Experiments has proved Livin can suppress cell apoptosis, what＇s more, it also was found to produce tLivin promoting apoptosis under the action of easpase-3/-7. Smac is a endogenous protein promoting the apoptosis of mitochondria,which can not result in the apoptosis of healthy cells, but can be released into cell plasma under the stimulation of apoptotie signaling, and promote apoptosis by specific binding and inhibiting the blocking effect of IAPs on caspases downstream. The two apoptosis-related proteins can regulate and control each other in the cells.