Auxiliary factors required for the accumulation and functioning of the thylakoid ATP synthase

叶绿体F1Fo-ATP合成酶（cpATPase）将ATP合成与光驱动的电化学质子梯度偶联，由两部分组成，膜状CFo亚复合物是质子通道，外围CF1亚复合物包含可逆ATP合成的催化位点。为了完全组装一个功能性的cpATPase复合物，需要各种辅助因子-要么是叶绿体定位的cpATPase亚基基因（atp基因）的表达，要么是组装过程本身。虽然在原核生物和酵母中已知F1Fo-ATP合成酶的几个组装因子，但在植物中只鉴定了组装因子ALB4。此外，一些参与atp基因表达的植物蛋白已经被描述。在这个项目中，我们想要表征模式植物拟南芥中cpATPase生物发生所需的两个新的辅助蛋白。第一个，AtCGL160，似乎是一个真正的组装因子，并与CFo亚复合物的亚基物理相互作用。有趣的是，AtCGL160除了包含一个植物特异性结构域外，还包含一个较短的部分，该部分与原核Atp1/UncI蛋白有关，该蛋白也与ATP合成酶组装有关。因此，我们希望阐明AtCGL160促进cpATPase组装的机制，该机制是否在原核Atp1/UncI蛋白和真核CGL160蛋白之间保守，并揭示AtCGL160的植物特异性部分的功能。我们已经确定的cpATPase生物发生所需的第二种蛋白质是AtCGLD11。与AtCGL160相反，AtCGLD11蛋白是可溶性的，其mRNA表达模式表明其在atp基因表达中起作用。因此，我们将描述AtCGLD11的功能，特别是在atp基因表达方面的功能，包括可以检测其与任何整套叶绿体基因和转录物相互作用的全局方法。

The chloroplast F1Fo-ATP synthase (cpATPase) couples ATP synthesis to the light-driven electrochemical proton gradient and comprise two parts, the membranous CFo subcomplex that is a proton channel and the peripheral CF1 subcomplex that contains the catalytic sites for reversible ATP synthesis. To fully assemble a functional cpATPase complex, various auxiliary factors are needed - either for the expression of the chloroplast-located genes for cpATPase subunits (the atp genes) or for the assembly process itself. While several assembly factors of the F1Fo-ATP synthase are known in prokaryotes and yeast, for plants only the assembly factor ALB4 has been identified yet. In addition, a couple of plant proteins involved in atp gene expression have been described. In this project, we want to characterize two novel auxiliary proteins required for cpATPase biogenesis in the model plant Arabidopsis thaliana. The first one, AtCGL160, appears to be a true assembly factor and interacts physically with subunits of the CFo subcomplex. Interestingly, AtCGL160 contains besides a plant-specific domain also a shorter part, which is related to the prokaryotic Atp1/UncI proteins that have been also brought into connection with ATP synthase assembly. Therefore, we want to clarify the mechanism by which AtCGL160 promotes cpATPase assembly, whether this mechanism is conserved between prokaryotic Atp1/UncI proteins and eukaryotic CGL160 proteins, and reveal the function of the plant-specific part of AtCGL160. The second protein that we have identified to be required for cpATPase biogenesis is AtCGLD11. In contrast to AtCGL160, the AtCGLD11 protein is soluble and displays an mRNA expression pattern that suggests a function in atp gene expression. Therefore, we will characterise the function(s) of AtCGLD11 particularly in atp gene expression, including global approaches that can detect its interactions with any of the entire set of chloroplast genes and transcripts.