Unravelling archaeal signal transduction networks

可逆的蛋白质磷酸化是细胞通过控制蛋白质的功能特性来响应外界刺激而快速响应环境变化的信号转导的主要机制。与我们对真核生物和细菌中蛋白质磷酸化的了解相比，对生命的第三个领域--古生代的这一过程仍然知之甚少。Crenarocota依赖于Hanks(真核)型蛋白激酶对丝氨酸、苏氨酸和酪氨酸的蛋白磷酸化，缺乏常见的细菌型两组分系统(His和Asp上的磷酸化)。为了初步了解蛋白质磷酸化在古生菌中的作用，我们分析了Sulfolobale的两个成员的光蛋白质组。这些研究揭示了大量的磷酸化蛋白，其酪氨酸磷酸化的数量出人意料地高，并且蛋白质磷酸化在碳源(Sulfolobus Solfararicus)和蛋白磷酸酶缺失(S.acidocaldarius)的响应中发生了重大变化。Saci-PTP和Saci-PP2A这两个已鉴定的蛋白磷酸酶的缺失导致Saci-PTP没有明显的表型，但Saci-PP2A的缺失导致细胞增大和在蜂群试验中的高运动性。在这项研究的基础上，我们确定了一些调节因子和其他因素，以蛋白质磷酸化依赖的方式影响古生菌的运动结构古生菌的表达。为了进一步揭示蛋白磷酸酶和蛋白激酶的生理功能，我们表达了酸性链球菌的酶，并构建了相应的缺失菌株。这种方法允许首次深入了解古细胞调控网络和中央碳水化合物代谢通过信号转导的调节。在未来的研究中，我们将继续研究调节(去)磷酸化网络的不同角色。接下来，我们将研究不同参与者之间的相互作用，以揭开这些网络的层次结构。

Reversible protein phosphorylation is the main mechanism of signal transduction that enables cells to rapidly respond to environmental changes by controlling the functional properties of proteins in response to external stimuli. Compared to our knowledge of protein phosphorylation in Eukaryotes and Bacteria, little is still known about this process in the third domain of life, the Archaea. Crenarchaeota depend on protein phosphorylation on Ser, Thr and Tyr by Hanks (eukaryotic)-type protein kinases and common bacterial-type two component systems (phosphorylation on His and Asp) are absent. To gain first insights into the role of protein phosphorylation in archaea, the phoshoproteome of two members of the Sulfolobales were analyzed. These studies revealed a high amount of phospho-proteins with an unexpected high number of tyrosine phosphorylation and major changes in protein phosphorylation in response to carbon source (Sulfolobus solfataricus) as well as protein phosphatase deletion (S. acidocaldarius). Deletion of the two identified protein phosphatases, Saci-PTP and Saci-PP2A, in S. acidocaldarius resulted in no obvious phenotype for the Saci-PTP, however, deletion of Saci-PP2A led to enlarged cells and hypermotility in swarming assays. Based on this study, we identified a number of regulators and other factors that influence the expression of the archaellum, the archaeal motility structure, in a protein phosphorylation dependent manner. To further unravel the physiological function of protein phosphatases and protein kinases the enzymes from S. acidocaldarius were expressed and the respective deletion strains were constructed. This approach allowed for first insights into the regulation of the archaellum regulatory network and central carbohydrate metabolism by signal transduction. In future studies we will continue to investigate the different players of the regulatory (de)phosphorylation network. Further on we will study the interplay of the different players in order to unravel the hierarchical structures of these networks.