CCaMK-Mediated Changes During Bacterial and Fungal Symbioses

钙/钙调蛋白依赖的蛋白激酶(CCaMK)在植物根系感知固氮细菌共生体并导致固氮根瘤形成的信号转导通路中起着关键作用。这个项目试图确定当来自潜在共生体的信号被接收并被传递到参与根瘤形成的下游效应器时，这种激酶在根中的作用。CCaMK是一种多功能蛋白质，其特征是在单个多肽中含有一个激动域、一个自身抑制域、一个钙调蛋白结合域和一个神经粘蛋白样钙结合域。CCaMK经历了两个步骤的钙调节，第一步是直接通过它的钙结合域，然后间接地通过它的钙/钙调蛋白结合域。最近的研究表明，CCaMK在细菌和真菌共生中都发挥着关键作用。在细菌相互作用导致固氮的过程中，CCaMK直接作用于根毛细胞中由细菌产生的信号分子NOD因子触发的钙振荡的下游。这项研究的直接目的是研究CCaMK的结构变化如何控制细菌入侵以及由此产生的共生关系。此外，该项目还将寻求确定和描述CCaMK潜在的下游互动合作伙伴(S)。遗传学研究表明，CCaMK处于介导植物与共生体相互作用的信号通路中的一个分支点的关键节点：一个分枝导致结瘤，另一个分枝导致菌根侵染。因此，这个项目可能会带来对真菌和细菌共生的新见解。该项目将使用遗传学、生物化学和细胞学的方法来解决植物领域的一个开创性问题：微生物相互作用。除了其农业和生态意义外，该项目的更广泛影响还包括培养本科生、研究生和博士后。将强调对对科学感兴趣的少数群体和妇女的培训。现场参与者将体验活跃的生物技术研究实验室的氛围。为了接触到更广泛的受众，WSU团队还将使用华盛顿州高等教育电信系统并组织现场研讨会。

A Ca2+/calmodulin-dependent protein kinase (CCaMK) has been implicated as a key player in the signal transduction cascade that follows perception of nitrogen fixing bacterial symbionts by plant roots and leads to the establishment of nitrogen-fixing root nodules. This project seeks to determine the role of this kinase in roots as signals from potential symbionts are received and transduced to downstream effectors involved in nodule formation. CCaMK, a multi-functional protein, is characterized by the presence of a kinase domain, an autoinhibitory domain, a calmodulin-binding domain and a neural visinin-like Ca2+-binding domain in a single polypeptide. CCaMK undergoes two steps of Ca2+ regulation, first directly through its Ca2+-binding domain and then indirectly through its Ca2+/calmodulin-binding domain. Recent investigations have revealed that CCaMK plays critical roles in both bacterial and fungal symbioses. During bacterial interactions which lead to nitrogen fixation, CCaMK acts immediately downstream of Ca2+ oscillations triggered in root hair cells by the bacterially produced signaling molecule, Nod factor. The immediate goal of this investigation is to study how the structural changes of CCaMK control bacterial invasion and the resulting symbiotic relationship. Furthermore, the project will also seek to identify and characterize CCaMK's potential downstream interaction partner(s). Genetic studies indicate that CCaMK is at a critical juncture of a branch point in the signaling pathway which mediates the interaction of plants with their symbionts: one branch leads to nodulation and the other to mycorrhizal infection. Hence, this project may lead to new insights into fungal as well as bacterial symbioses. This project will use genetic, biochemical and cellular approaches to address a seminal question in the area of plant:microbe interactions. In addition to its agricultural and ecological significance the broader impacts of the project include training undergraduates, graduate students and postdocs. Training of minorities and women who are interested in science will be emphasized. On-site participants will experience the atmosphere of an active biotechnology research laboratory. To reach a wider audience, the WSU team will also use the Washington State Higher Education Telecommunication System and organize onsite workshops.