MECHANISMS OF ACTIVATION OF ICE-LIKE CYSTEINE PROTEASES

描述：ICE样蛋白水解酶(Caspase)家族的成员在 在执行细胞凋亡中起着中心的和进化上保守的作用。 几种哺乳动物半胱氨酸天冬氨酸氨基转移酶最近在 S实验室。包括CPP32、Mch2、Mch3、Mch5、Mch6和Mih1。 与线虫不同的是，在线虫中，CED-3 caspase是主要的刽子手 细胞凋亡，最近的观察表明，细胞凋亡的执行力更高 真核生物可能涉及多个半胱氨酸天冬氨酸酶的协同作用。这些 蛋白水解酶可能是可扩增的凋亡蛋白酶级联反应的组成部分。 类似于补体激活的级联过程。然而，它并不是 然而，目前尚不清楚这些半胱氨酸天冬氨酸酶是全部还是很少在哺乳动物体内发挥作用。 细胞凋亡级联。此外，目前还不知道酶原是如何 半胱氨酸酶被激活，当细胞 进入细胞凋亡的承诺阶段。一种可能性是存在 直接与之相互作用的上游细胞死亡效应因子或激活剂 这些过程中的一个或多个或间接地与 半胱氨酸氨基转移酶激活途径。最近的观察结果支持了这一点 ProMch4、proMch5和Pro-ICH-1含有能够 与凋亡适配分子FADD/Mort1和CRADD/Raidd相互作用， 分别进行了分析。这些原域也可能与其他小说相互作用 Fas/TNFR1凋亡途径中的同源死亡效应蛋白和 可能存在于其他的凋亡途径中。ProMch6还包含一个长的 与CED-3前结构域高度同源的前结构域，表明 其激活和相互作用的机制可能类似于 CED-3在发育细胞死亡途径中的作用。因此，实验 是为了研究上游caspase的前域的作用。 (Mch4、Mch5、Mch6和ICH-1)的激活机制。这个 这些蛋白水解酶的凋亡潜能及其与细胞死亡的相互作用 效应物，如FADD和CRADD，或抑制剂，如 细胞凋亡(IAP)和Bcl2家族成员也将被检测。 还建议进行实验以识别和克隆新的死亡效应器或 可能与上游蛋白水解酶相互作用的抑制剂。这个 建议研究糖皮质激素和Fas受体的细胞凋亡模型 体内半胱氨酸氨基转移酶的参与和激活。预计 这些研究将有助于阐明激活机制。 这类重要的蛋白酶。这可能会为新的 癌症和其他退行性疾病的化疗方法 细胞死亡参与了病理过程。

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.