Atp11p and Atp12p are members of two chaperone families essential for assembly of the mitochondrial ATP synthase in Saccharomyces cerevisiae and Homo sapiens. However, the role of their homologs in higher plants is unclear with regard to the assembly of both chloroplast ATP synthase (cpATPase) and mitochondrial ATP synthase (mtATPase). Here, we show that loss of either Atp11 or Atp12 is lethal in Arabidopsis. While Atp12 is only localized in mitochondria, Atp11 is present both in chloroplasts and mitochondria. Yeast two-hybrid analyses showed that, as their homologs in yeast, Atp11 specifically interacts with the β subunit of the mtATPase and cpATPase, and Atp12 interacts with the α subunit of the mtATPase, implying that Atp11 and Atp12 fulfill a conserved task during assembly of ATP synthase. However, the binding sites for Atp11 in the β subunit of mtATPase and cpATPase are slightly different, suggesting that the mechanisms of action may have evolved in different ways. Although Atp11 interacts with cpATPase β subunit as the two assembly factors BFA3 and BFA1, they bind to different sites of the β subunit. These results indicate that Atp11 is involved in the assembly of both cpATPase and mtATPase but Atp12 is specifically required for the assembly of mtATPase in higher plants.

Atp11p和Atp12p是两个分子伴侣家族的成员，这些分子伴侣对于线粒体ATP合酶的组装至关重要 酿酒酵母 和 智人。然而，就叶绿体ATP合酶（cpATPase）和线粒体ATP合酶（mtATPase）的组装而言，其同源物在高等植物中的作用尚不清楚。在这里，我们表明，Apt11或Atp12的丢失在拟南芥中是致命的。虽然Atp12仅位于线粒体中，但Atp11既存在于叶绿体中也存在于线粒体中。酵母两杂交分析表明，作为它们在酵母中的同源物，Atp11与mtATPase和cpATPase的β亚基特异性相互作用，而Atp12与mtATPase的α亚基相互作用，这暗示Atp11和Atp12在组装过程中完成了保守的任务。 ATP合酶。但是，mtATPase和cpATPaseβ亚基中Atp11的结合位点略有不同，这表明其作用机理可能以不同的方式演变。尽管Atp11作为两个装配因子BFA3和BFA1与cpATPaseβ亚基相互作用，但它们结合到β亚基的不同位点。这些结果表明Atp11参与了cpATPase和mtATPase的组装，但是Atp12是高等植物中mtATPase组装的特别要求。