Characterization of the plant mitochondrial twin arginine translocation pathway

双精氨酸转位(TAT)途径在细菌和叶绿体中已被广泛研究，并在光合作用、能量代谢和铁磷代谢中发挥重要作用。TAT途径是非常有趣的，因为它们运输完全折叠的蛋白质进入和跨膜。这与其他以未折叠状态运输蛋白质的运输途径形成了鲜明对比。我们最近的数据表明，植物线粒体也包含一个潜在的TAT途径。可以证明，该途径对植物线粒体的生物发生是必不可少的，进而对植物的生长发育也是必不可少的。然而，到目前为止，只有一种底物被确定为该途径，为什么该途径是必不可少的确切原因仍然是一个悬而未决的问题。这项拟议的项目试图进一步剖析植物线粒体TAT途径的确切作用和机制。研究将包括确定线粒体TAT途径的确切底物，它在植物线粒体生物发生中扮演的角色，以及最后它的活动所需的亚基。最后一个需要回答的进化问题是，为什么植物线粒体需要TAT途径，而其他生物，如酵母和人类的线粒体则不包含TAT途径。

Twin arginine translocation (Tat) pathways have been extensively studied in bacteria and chloroplasts and have essential roles in photosynthesis, energy metabolism and iron and phosphate metabolism. Tat pathways are extremely interesting as they transport fully folded proteins into and across membranes. This is in contrast to other transport pathways which transport proteins in an unfolded state. Our recent data indicate that plant mitochondria also contain a potential Tat pathway. It could be demonstrated that this pathway is essential for plant mitochondrial biogenesis and by extension is essential for plant growth and development. However, to date only one substrate was identified for the pathway and the exact reason as to why the pathway is essential is still an open question. The proposed project seeks to further dissect the exact roles and mechanisms of the plant mitochondrial Tat pathway. Investigations will include identifying the exact substrates of the mitochondrial Tat pathway, what role it plays in plant mitochondrial biogenesis, and finally the subunits required for its activity. One final evolutionary question to answer is why do plant mitochondria require a Tat pathway, while the mitochondria of other organisms like yeast and humans do not contain a Tat pathway.