Division of Pulmonary and Critical Care, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Free Radic Biol Med. 2011 May 15;50(10):1252-62. doi: 10.1016/j.freeradbiomed.2011.02.031. Epub 2011 Mar 5.
Fas-mediated apoptosis is a crucial cellular event. Fas, the Fas-associated death domain, and caspase 8 form the death-inducing signaling complex (DISC). Activated caspase 8 mediates the extrinsic pathways and cleaves cytosolic BID. Truncated BID (tBID) translocates to the mitochondria, facilitates the release of cytochrome c, and activates the intrinsic pathways. However, the mechanism causing these DISC components to aggregate and form the complex remains unclear. We found that Cav-1 regulated Fas signaling and mediated the communication between extrinsic and intrinsic pathways. Shortly after hyperoxia (4 h), the colocalization and interaction of Cav-1 and Fas increased, followed by Fas multimer and DISC formation. Deletion of Cav-1 (Cav-1-/-) disrupted DISC formation. Further, Cav-1 interacted with BID. Mutation of Cav-1 Y14 tyrosine to phenylalanine (Y14F) disrupted the hyperoxia-induced interaction between BID and Cav-1 and subsequently yielded a decreased level of tBID and resistance to hyperoxia-induced apoptosis. The reactive oxygen species (ROS) scavenger N-acetylcysteine decreased the Cav-1-Fas interaction. Deletion of glutathione peroxidase-2 using siRNA aggravated the BID-Cav-1 interaction and tBID formation. Taken together, these results indicate that Cav-1 regulates hyperoxia/ROS-induced apoptosis through interactions with Fas and BID, probably via Fas palmitoylation and Cav-1 Y14 phosphorylation, respectively.
Fas 介导的细胞凋亡是一种重要的细胞事件。Fas、Fas 相关死亡结构域和胱天蛋白酶 8 形成死亡诱导信号复合物（DISC）。激活的胱天蛋白酶 8 介导外在途径并切割细胞质 BID。截断的 BID（tBID）易位到线粒体，促进细胞色素 c 的释放，并激活内在途径。然而，导致这些 DISC 成分聚集并形成复合物的机制尚不清楚。我们发现 Cav-1 调节 Fas 信号并介导外在和内在途径之间的通讯。在高氧（4 小时）后不久，Cav-1 和 Fas 的共定位和相互作用增加，随后 Fas 多聚体和 DISC 形成。Cav-1 的缺失（Cav-1-/-）破坏了 DISC 的形成。此外，Cav-1 与 BID 相互作用。将 Cav-1 Y14 酪氨酸突变为苯丙氨酸（Y14F）破坏了高氧诱导的 BID 和 Cav-1 之间的相互作用，随后导致 tBID 水平降低并对高氧诱导的细胞凋亡产生抗性。活性氧（ROS）清除剂 N-乙酰半胱氨酸降低了 Cav-1-Fas 相互作用。使用 siRNA 敲除谷胱甘肽过氧化物酶-2 会加剧 BID-Cav-1 相互作用和 tBID 形成。总之，这些结果表明 Cav-1 通过与 Fas 和 BID 的相互作用调节高氧/ROS 诱导的细胞凋亡，可能分别通过 Fas 棕榈酰化和 Cav-1 Y14 磷酸化。
