酵母线粒体的磷脂转运

线粒体是一种由两层膜包被的细胞器,其功能和结构的稳定性取决于线粒体膜上精确的磷脂组成及分布。线粒体膜上的大部分脂类物质由内质网合成,既而转运到线粒体。而部分脂类利用内质网上产生的前体,在线粒体内膜上合成。由此可见,线粒体膜脂的生物合成需要线粒体与内质网以及线粒体外膜(outer mitochondrial membrane, OMM)与内膜(inner mitochondrial membrane, IMM)之间进行大量的脂质转运。目前认为,这种运输过程既可在拴系因子(tether factors)形成的膜结合部位(membrane contact sites, MCSs)内发生,也可借助脂质转运蛋白(lipid transfer proteins, LTPs)完成。近年来,研究者以酵母为对象,建立了多种线粒体磷脂转运(phospholipid trafficking)的模型,这使人们初步理解了线粒体磷脂转运的机制。本综述总结了酵母线粒体磷脂转运的最新发现,并对这些磷脂转运的模型进行了讨论,以期为今后深入了解线粒体脂类代谢提供参考。

Mitochondrial Phospholipid Trafficking in Saccharomyces cerevisiae

Mitochondria are double-membrane organelles, whose function and architecture rely on the precise distribution and composition of phospholipids. The majority of lipids of the mitochondrial membrane are synthesized in the endoplasmic reticulum (ER) and transported to the mitochondria, whereas a portion of lipids are synthesized in the inner membrane of mitochondria from ER derived precursors. Thus, the biosynthesis of mitochondrial membrane phospholipids requires extensive lipid exchange between the ER and mitochondria as well as between the outer and the inner mitochondrial membranes. This process is thought to occur at membrane contact sites by membrane tether factors or with the aid of lipid transfer proteins. Over recent years, multiple models for lipid trafficking have been established on the basis of the findings from the yeast, thus generating a preliminary insight of the mechanisms controlling mitochondrial lipid trafficking. In this review, we summarize the latest discoveries of mitochondrial phospholipid trafficking and discuss the models of phospholipid trafficking in Saccharomyces cerevisiae, hoping to provide a basis for deep understanding of mitochondrial lipid metabolism in the future.