CD95 (APO-1/Fas) has become the prototype of a death domain containing receptor and is the best studied member of the death receptors that activate the extrinsic apoptosis pathway. This pathway is initiated by recruitment and activation of caspase-8, an initiator caspase, in the death-inducing signaling complex (DISC) followed by direct cleavage of downstream effector caspases. In contrast, the intrinsic apoptosis pathway starts from within the cell either by direct activation of caspases or through intracellular changes such as DNA damage resulting in the release of a number of pro-apoptotic factors from the intermembrane space of mitochondria. The release of these factors results in the activation of another initiator caspase, caspase-9, and ultimately in the activation of effector caspases in a protein complex called the apoptosome. In recent years, it has become apparent that there is cross talk between the extrinsic and intrinsic pathway. In the death receptor pathway of apoptosis induction, the best characterized connection between the two pathways is the Bcl-2 family member Bid which translocates to mitochondria after cleavage by caspase-8 causing pro-apoptotic changes. Cells that die through CD95 without help from mitochondria are called Type I cells, whereas cells in which CD95-mediated death relies mostly on the intrinsic pathway are called Type II. This review focuses on recent developments in the delineation of the biochemistry and the physiological function of the two CD95 pathways.

中文翻译：

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CD95 I型/ II型模型。

CD95（APO-1 / Fas）已成为包含死亡结构域的受体的原型，并且是激活外源性细胞凋亡途径的死亡受体的最佳研究成员。该途径通过在死亡诱导信号复合物（DISC）中募集和激活caspase-8（一种启动子caspase）来启动，然后直接切割下游效应子胱天蛋白酶。相反，固有的凋亡途径是通过半胱天冬酶的直接激活或通过细胞内变化（例如DNA损伤）从细胞内开始的，从而导致许多促凋亡因子从线粒体内膜释放。这些因子的释放导致另一种引发剂胱天蛋白酶caspase-9的活化，并最终导致一种称为凋亡小体的蛋白质复合物的效应胱天蛋白酶的活化。近年来，很明显，外部和内部途径之间存在串扰。在凋亡诱导的死亡受体途径中，这两种途径之间最有特色的联系是Bcl-2家族成员Bid，它被caspase-8裂解后易位至线粒体，引起促凋亡变化。在没有线粒体帮助的情况下通过CD95死亡的细胞称为I型细胞，而其中CD95介导的死亡主要依赖于内在途径的细胞称为II型细胞。这篇综述着重于两个CD95途径的生物化学和生理功能的描述方面的最新进展。两条途径之间最有特色的联系是Bcl-2家族成员Bid，它在被caspase-8切割后引起细胞凋亡变化，并易位至线粒体。在没有线粒体帮助的情况下通过CD95死亡的细胞称为I型细胞，而其中CD95介导的死亡主要依赖于内在途径的细胞称为II型细胞。这篇综述着重于两个CD95途径的生物化学和生理功能的描述方面的最新进展。两条途径之间最有特色的联系是Bcl-2家族成员Bid，它在被caspase-8切割后引起细胞凋亡变化，并易位至线粒体。在没有线粒体帮助的情况下通过CD95死亡的细胞称为I型细胞，而其中CD95介导的死亡主要依赖于内在途径的细胞称为II型细胞。这篇综述着重于两个CD95途径的生物化学和生理功能的描述方面的最新进展。