Biogenesis of mitochondrial apoptotic proteins

描述（由申请人提供）：除了在代谢中起中心作用外，线粒体在细胞凋亡/程序性细胞死亡中起关键作用。线粒体膜间隙是介导蛋白质（细胞色素c、Smac/DIABLO、HtrA 2/OMI）、DNA（凋亡诱导因子（AIF）和核酸内切酶G）以及我们目前研究中的RNA（PNTR）降解的几种凋亡组分的家园。Bcl-2/Bax家族的许多促凋亡蛋白和抗凋亡蛋白靶向线粒体外膜。此外，通常驻留在其他亚细胞区室的蛋白质，如Nur 77和Muc 1，也在细胞凋亡期间靶向线粒体。细胞器中的常驻蛋白质遵循非常特定的途径输入和组装。据推测，这些凋亡蛋白利用特定的途径进行生物合成，这对于它们在凋亡中的高度调节作用是重要的。本研究的目的是利用遗传学和生物化学相结合的方法对分离的线粒体进行研究。酿酒酵母，细胞培养和动物模型来表征线粒体膜间隙凋亡蛋白的生物发生。本提案的第一个目标是根据降解目标（即，DNA、蛋白质或RNA），以PNTR开始。第二个目的是研究PNTR从膜间隙的组装和释放。最后的目的是研究PNTR在维持呼吸中的作用及其与细胞凋亡的联系，因为PNTR的丢失破坏氧化磷酸化并降低膜电位。与以前主要关注单个组分的研究相反，该提案将专门关注与线粒体膜间隙中凋亡蛋白的生物发生相关的事件，从而为该隔室在程序性细胞死亡中的作用提供新的见解。我们将确定不同的凋亡蛋白是否可能共享保守的生物发生途径，这可能是一个理想的目标，为发展新的方法来调节几个凋亡途径在同一时间。这种应用在公共卫生领域具有更广泛的影响，因为与细胞凋亡相关的线粒体事件会导致癌症和神经退行性疾病。

DESCRIPTION (provided by applicant): In addition to a central role in metabolism, mitochondria play a critical role in apoptosis/programmed cell death. The mitochondrial intermembrane space is home to several apoptotic components that mediate the degradation of proteins (cytochrome c, Smac/DIABLO, HtrA2/OMI), DNA (apoptosis inducing factor (AIF), and Endonuclease G), and, from our current studies, RNA (PNPase). Many pro- and anti-apoptotic proteins of the Bcl-2/Bax family are targeted to the mitochondrial outer membrane. Additionally, proteins normally resident to other subcellular compartments, such as Nur77 and Muc1, are also targeted to mitochondria during apoptosis. Resident proteins of the mitochondrion follow very specific pathways for import and assembly in the organelle. Presumably, these apoptotic proteins utilize specific pathways for biogenesis that are important for their highly regulated role in apoptosis. The goal of this proposal is to use a combined genetic and biochemical approach in isolated mitochondria, S. cerevisiae, cell culture, and animal models to characterize the biogenesis of the mitochondrial intermembrane space apoptotic proteins. The first objective of this proposal is to characterize the import pathway of representatives in the various categories, based on the target of degradation (i.e., DNA, protein, or RNA), beginning with PNPase. The second objective is to investigate the assembly and release of PNPase from the intermembrane space. The final objective is to investigate the role of PNPase in maintaining respiration and its link to apoptosis because loss of PNPase disrupts oxidative phosphorylation and lowers the membrane potential. In contrast to previous studies that have focused primarily on the individual components, this proposal will focus specifically on the events related to the biogenesis of apoptotic proteins in the mitochondrial intermembrane space and thus provide novel insights into the role of this compartment in programmed cell death. We will determine if the different apoptotic proteins might share conserved biogenesis pathways, which could be an ideal target for the development of new approaches to modulate several apoptotic pathways at one time. This application has a broader impact in public health because the mitochondrial events linked to apoptosis contribute to cancer and neurodegenerative diseases.