Evolution of AGC1 kinase-mediated polarity modules in early land plant development

动物和植物细胞在其质膜上建立极性区域以控制细胞分裂和细胞分化。在动物中，极性PAR蛋白的调节是很好理解的，并且是研究许多分化过程的重要模型。植物中没有PAR直系同源物，但我们有证据表明，高等植物中各种极性过程的形成需要所谓的AGC 1激酶，例如来自拟南芥的D6 PK或PAX。AGC1激酶首次出现在苔藓和地钱中，因此我们假设它们在向陆地生命过渡的重要进化变化中发挥作用。AGC1激酶的一个非常好理解的功能是PIN生长素转运蛋白的激活，其独立于AGC1激酶定位在质膜中。在高等植物中，PIN蛋白的极性由所谓的AGC3激酶调节，然而，早期陆地植物中不存在这种激酶。因此，我们希望研究早期陆地植物的PIN蛋白是否已经可以响应AGC3信号，以及AGC1激酶是否可能在早期陆地植物中发挥AGC3激酶的作用。通过这些研究，我们将能够为理解早期陆地植物的分子适应做出重要贡献。

Animal and plant cells establish polar regions on their plasma membranes to control cell division and cell differentiation. In animals, the regulation of polar PAR proteins is well understood and an important model for the study of numerous differentiation processes. There are no PAR orthologues in plants but we have evidence that so-called AGC1 kinases, such as D6PK or PAX from Arabidopsis thaliana, are needed for the formation of various polarity processes in higher plants. AGC1 kinases appear for the first time in mosses and liverworts, and we therefore postulate that they play a role in important evolutionary changes in the transition to terrestrial life. A very well understood function of the AGC1 kinases is the activation of the PIN auxin transporters, which localize - independently of AGC1 kinases - in the plasma membrane. In higher plants, the polarity of the PIN proteins is regulated by so-called AGC3 kinases, which, however, are absent from early land plants. We therefore want to investigate whether PIN proteins from early land plants can already respond to AGC3 signaling and whether AGC1 kinases may play the role of AGC3 kinases in early land plants. With these studies, we will be able to make an important contribution to the understanding of molecular adaptations in early land plants.