MECHANISMS OF ACTIVATION OF ICE-LIKE CYSTEINE PROTEASES

描述：ICE样蛋白酶（半胱天冬酶）家族成员发挥作用， 在细胞凋亡的执行中起着中心的和进化上保守的作用。 近年来，一些哺乳动物的半胱天冬酶已被鉴定和克隆， P.I.的实验室。 这些包括CPP 32、Mch 2、Mch 3、Mch 5、Mch 6和Mih 1。 不像C。其中CED-3半胱天冬酶是主要的刽子手， 细胞凋亡，最近的观察表明，在更高的细胞凋亡的执行， 真核生物可能涉及多个半胱天冬酶的协调作用。 这些 这些蛋白酶可能是一种可降解的凋亡蛋白酶级联反应的组分， 类似于补体激活的级联反应。 然而， 目前尚不清楚这些半胱天冬酶中的全部或少数是否在哺乳动物中起作用。 凋亡级联反应 此外，尚不清楚， 半胱天冬酶被激活，当细胞被激活时，是什么触发了它们的激活 进入细胞凋亡的定型期。 一种可能是 上游细胞死亡效应物或激活物， 这些前体蛋白酶中的一种或多种或间接地与这些前体蛋白酶的组分结合。 半胱天冬酶激活途径。 最近的观察结果支持了这一点， proMch 4、proMch 5和pro-ICH-1含有长的N-末端前结构域，其能够 与凋亡衔接分子FADD/Mort 1和CRADD/RAIDD的相互作用， 分别 这些前结构域也可以与其他新的结构域相互作用。 FAS/TNFR 1凋亡途径中的同源死亡效应蛋白， 可能在其他凋亡途径中。 ProMch 6还包含一个长 与CED-3前结构域高度同源的前结构域，表明 其激活和相互作用机制可能类似于 CED-3在发育细胞死亡途径中的作用 因此，实验 的作用，提出了检查上游半胱天冬酶的前结构域 (Mch4、Mch 5、Mch 6和ICH-1）的活化机制。 的 凋亡潜力和这些蛋白酶与细胞死亡的相互作用 效应物如FADD和CRADD，或抑制剂如FADD和CRADD的抑制剂， 细胞凋亡（IAP）和Bcl 2家族成员，也将进行检查。 实验还提出了鉴定和克隆新的死亡效应物或 可能与上游蛋白酶相互作用的抑制剂。 的 糖皮质激素和Fas受体模型的细胞凋亡提出了研究 半胱天冬酶在体内的参与和激活。 预计各国 这些研究将有助于阐明激活机制 这类重要的蛋白酶。 这可能为新的 癌症和其他退行性疾病的化疗方法， 细胞死亡参与病理过程。

DESCRIPTION: Members of the family of ICE-like proteases (caspases) play a central and evolutionarily conserved role in the execution of apoptosis. Several mammalian caspases have been identified and cloned recently in the P.I.'s laboratory. These include CPP32, Mch2, Mch3, Mch5, Mch6 and Mih1. Unlike in C. elegans where CED-3 caspase is the major executioner of apoptosis, recent observations suggest that execution of apoptosis in higher eukaryotes may involve the coordinated action of multiple caspases. These proteases might be components of an amplifiable apoptotic protease cascade similar to the cascade of complement activation. Nevertheless, it is not yet clear whether all or few of these caspases play a role in the mammalian apoptotic cascade. In addition, it is not known how the proenzymes of caspases are activated and what triggers their activation when the cell enters the committed phase of apoptosis. One possibility is the existence of upstream cell death effectors or activators that interact directly with one or more of these procaspases or indirectly with components of the caspase activation pathway. This is supported by recent observations that proMch4, proMch5 and pro-ICH-1 contain long N-terminal prodomains capable of interaction with the apoptotic adapter molecules FADD/Mort1 and CRADD/RAIDD, respectively. These prodomains may also interact with other novel homologous death effector proteins in the FAS/TNFR1 apoptotic pathway and possibly in other apoptotic pathways. ProMch6 also contains a long prodomain that is highly homologous to the CED-3 prodomain, suggesting that its mechanism of activation and interactions might be similar to that of CED-3 in the developmental cell death pathway. Consequently, experiments are proposed to examine the role of the prodomain of upstream caspases (Mch4, Mch5, Mch6 and ICH-1) in their mechanism of activation. The apoptotic potential and interactions of these proteases with cell death effectors such as FADD and CRADD, or inhibitors such as inhibitors of apoptosis (IAPs) and Bcl2 family members, will also be examined. Experiments are also proposed to identify and clone novel death effectors or inhibitors that might interact with the upstream proteases. The glucocorticoid and Fas receptor models of apoptosis are proposed to study the involvement and activation of caspases in vivo. It is anticipated that these studies will contribute to elucidation of the mechanism of activation of this important class of proteases. This could lay the foundation for new chemotherapeutic approaches in cancer and other degenerative diseases where cell death is involved in the pathologic process.