Multifarious roles of the smallest Arabidopsis thaliana MAPKKKs clade (MAPKKK19, 20 and 21) as an integrative hub for plant pathogen interactions, growth, development and reproduction.

沟通和信息传递是一切，不仅对我们的日常生活，而且对生物体的每一个细胞。细胞中的信息传递被称为信号转导。许多元素参与细胞信号传导，通常通过级联反应介导刺激的感知和处理。这些分子电路精确地检测、放大和整合外部信号以产生下游响应。因此，对刺激的感知可以导致基因表达、酶活性、蛋白质定位或半衰期的变化，从而导致细胞稳态的重大变化。蛋白激酶家族就是这样一组主要的信号蛋白的例证。激酶是一种通过在特定氨基酸上添加磷酸基团来修饰其他蛋白质的酶，最常见的目标是丝氨酸、苏氨酸和酪氨酸。这么小的改变怎么会对蛋白质产生深远的影响呢？因为蛋白质中磷酸化的氨基酸作为新的实体，改变了蛋白质表面的化学性质，从而使新的蛋白质相互作用的形成成为可能。为什么它被如此广泛地使用？因为它是可逆的：激酶在底物上添加磷酸基团——这会改变底物的性质，进而影响其相互作用的潜力——然后磷酸酶可以去除磷酸基团。这导致了基于磷酸化的信号传导的“书写者-读取者-擦除者”三联体。磷酸化作为一种交流手段，在植物等无法摆脱危险或不利环境条件的无根生物中似乎更为重要。这可以通过蛋白激酶家族在植物中的贡献来说明，与其他真核生物相比，它们代表了蛋白质组（生物体的蛋白质集合）的更大比例。例如，在植物模式物种拟南芥中，激酶占蛋白质组的4%，而在人类、线虫、果蝇或啤酒酵母中，这一比例约为2%。其中，两个主要家族，受体激酶（RK）家族（bbb600）和MAPK（丝裂原活化蛋白激酶）超家族（>00），占所有拟南芥蛋白激酶的70%。因此，激酶处于信号传导的最前沿。我们目前的研究项目集中在细胞-细胞通讯的多个方面，从植物生殖到涉及蛋白激酶的信号级联反应在配子体发育中的作用，例如，胚珠和花粉的胚囊，以及植物先天免疫。在本研究项目中，我们重点关注新组装的MAPK级联的作用，该级联影响植物生命的许多方面，例如，生长，有性生殖和疾病（植物先天免疫），通过分析缺乏这些激酶的突变植物来确定。

Communication and information transfer is everything, not only for our day-to-day lives but also for each and every cell of an organism. Information transfer in cells is better known as signal transduction. Numerous elements take part in cellular signaling and generally act through cascades that mediate sensing and processing of stimuli. These molecular circuits precisely detect, amplify, and integrate external signals to generate downstream responses. Thus, perception of a stimulus can lead to changes in gene expression, enzyme activity, localization of a protein or its half-life, leading to major changes in cell homeostasis. The protein kinase family exemplifies such a major group of signaling proteins. Kinases are enzyme that modifies other proteins by chemically adding a phosphate groups to specific amino acids, the most prevalent targets being serine, threonine and tyrosine. How can such a small modification exert profound effects on proteins? Because phosphorylated amino acids in proteins act as new entities, modifying the chemical nature of the protein's surface, thereby enabling the formation of new protein-protein interactions. Why is it so widely used? Because it is reversible: the kinase adds a phosphate group on a substrate - this modifies the substrate's properties, which in turn influence its interaction potential - then a phosphatase can remove the phosphate group. This leads to the writer-reader-eraser triad of phosphorylation based signaling. Phosphorylation as a means of communication seems to be even more important in sessile organisms like plants that cannot flea danger or adverse environmental conditions. This can be illustrated by the contribution of the protein kinase's family in plants, which represent a much larger fraction of the proteome (the protein ensemble of an organism) compared to other eukaryotes. For example, in the plant model species Arabidopsis thaliana, kinases represent 4% of the proteome compared to ~2% in humans, nematodes, fruit fly or brewer's yeast. Of these, two major families, the receptor kinase (RK) family (>600) and the MAPK (Mitogen-Activated Protein Kinases) superfamily (>100), account for 70% of all Arabidopsis protein kinases. Kinases are thus at the forefront of signaling. Our current research program focuses on multiple aspects of cell-cell communication, from plant reproduction to the role of signaling cascades involving protein kinases in gametophytes development, e.g., the embryo sac of the ovule and the pollen, and in plant innate immunity. In this research project, we focus on the role of a newly assembled MAPK cascade that affects numerous aspects of the life of a plant, e. g., growth, sexual reproduction, and diseases (plant innate immunity) as determined by the analysis of mutant plants lacking these kinases.