STRUCTURAL FEATURES OF TRANSMEMBRANE SIGNALING IN PLANTS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 植物细胞表面信号的转换控制着植物的发育、激素反应、避免自花授粉和抗病性。 植物中的跨膜信号传导通过受体样激酶（RLK）CLAVATA 1与激酶相关蛋白磷酸酶（KAPP）的相互作用来例示。 这一对在质膜的内表面上相互作用，以指导模式植物拟南芥的茎和花分生组织的发育。将研究KAPP FHA结构域如何与RLK激酶结构域相互作用的基本问题。 FHA结构域是一类新发现的磷酸丝氨酸/磷酸苏氨酸结合结构域，在真核生物中广泛存在于多种蛋白质-蛋白质信号传导环境中。 没有报道KAPP或RLK的3D原子结构。KAPP的独特FHA结构域的高质量结构以及其骨架柔性将通过NMR测定游离和结合磷酸肽的结构域。磷酸肽与KAPP FHA结构域相互作用的特异性的序列决定因素将使用定点诱变，筛选磷酸/thr肽结合，和热力学的磷酸肽结合最亲的FHA结构域进行探索。 为了进一步探索KAPP如何与CLAVATA 1相互作用，将对该RLK的丝氨酸激酶结构域的结构进行建模。 该项目将深入研究植物中一类信号蛋白在信号转换过程中如何特异性地相互作用。它还将为其他生物体中FHA介导的蛋白质-蛋白质相互作用增添前景。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Switching of signals at the surface of plant cells controls plant development, hormone response, avoidance of self-pollination, and disease resistance. Transmembrane signaling in plants is exemplified by the interactions of the receptor-like kinase (RLK) CLAVATA1 with kinase-associated protein phosphatase (KAPP). This pair interacts on the inner surface of the plasma membrane to guide the development of the shoot and flower meristems of the model plant Arabidopsis. The fundamental question of how the KAPP FHA domain interacts with an RLK kinase domain will be investigated. The FHA domain is a newly described class of phosphoserine / phosphothreonine-binding domain which is ubiquitous among eukaryotes in diverse protein-protein signaling contexts. No 3D atomic structures of KAPP or of an RLK have been reported. A high quality structure of the distinctive FHA domain of KAPP, as well as its backbone flexibility, will be determined by NMR for the domain both free and bound to a phosphopeptide. Sequence determinants of the specificity of phosphopeptide interactions with the KAPP FHA domain will be explored using site-directed mutagenesis, screening of phosphoser/thr peptide binding, and thermodynamics of the binding of phosphopeptides most avid for the FHA domain. To further probe how KAPP interacts with CLAVATA1, the structure of the serine kinase domain of this RLK will be modeled. This project will provide insights into how a class of signaling proteins in plants interact specifically during the process of signal switching. It will also add perspective to FHA-mediated protein-protein interactions in other organisms.