Functional Motions of Modular Signaling Proteins

描述(由申请人提供)：理解细胞周期疾病(如癌症)的发病机制是复杂的，因为必须考虑蛋白质-蛋白质相互作用的多样性。蛋白质相互作用作为高度互联网络的观点从一开始就包含了这种复杂性，并为发现新的治疗靶点和策略带来了希望。为了实现这一前景，我们必须了解关键网络蛋白--模块化信号蛋白--如何驱动细胞信号转导。越来越多的证据表明，这些蛋白质具有显著的构象动力学，并随着靶标结合而改变。这表明网络信号和蛋白质运动之间存在功能联系。然而，大多数对蛋白质相互作用网络的分析都隐含地假设了静态结构。因此，确定构象动力学对蛋白质-蛋白质相互作用网络中信号的影响仍然是生物学中的一个突出挑战。我们提出的研究的目的是加深我们对模块信号蛋白功能运动如何影响正常和致病网络信号的理解，并最终为以动态模块蛋白为靶点的配体的设计提供新的策略。为了实现这一目标，我们探索了我们最近工作中提出的两个假设：(1)模块化信号蛋白改变其识别环的序列以增强结合偏好；这对相互作用多样性和网络中的信号路由有影响；(2)模块信号蛋白使用域间相互作用来刺激变构调节催化活性的动力学变化；这对单个蛋白质处理化学信号的机制有影响。为了研究这些假设，我们建议对模型蛋白质人Pin1的动力学-活性关系进行核磁共振研究。Pin1是一种有丝分裂调节器，由一个灵活连接到催化模块(异构酶结构域)的对接模块(WW结构域)组成，是目前的癌症靶点。其强大的生化特性使其成为探索模块蛋白质基本性质的极佳模型系统。研究将使用全长Pin1、其隔离结构域和已知的Pin1底物/抑制剂。公共卫生相关性这项建议描述了一个模型系统的研究，以了解内在蛋白质动力学如何使生物网络能够维持细胞的生存和生长。这项拟议的研究将为疾病的分子起源提供新的见解。

DESCRIPTION (provided by applicant): Understanding the pathogenesis of cell cycle diseases (e.g., cancer) is complex due to the multiplicity of protein-protein interactions that must be considered. The view of protein-protein interactions as highly inter-connected networks embraces this complexity at the outset, and holds out the promise for the discovery of new therapeutic targets and strategies. To realize this promise, we must understand how key network proteins - modular signaling proteins - drive cellular signal transduction. Mounting evidence shows that these proteins have significant conformational dynamics that change upon target binding. This suggests a functional link between network signaling and protein motion. Yet, most analyses of protein interaction networks implicitly assume static structures. Hence, defining the influence of conformational dynamics on signaling within protein-protein interaction networks remains an outstanding challenge in biology. The goal of our proposed research is to deepen our understanding of how the functional motions of modular signaling proteins affects normal versus pathogenic network signaling, and eventually suggest new strategies for the design of ligands targeting dynamic modular proteins. Toward this goal, we explore two hypotheses developed from our recent work: (1) modular signaling proteins vary the sequences of their recognition loops to enhance binding preference; this has implications for interaction diversity and signal routing within the network; (2) modular signaling proteins use inter-domain interactions to stimulate changes in dynamics that allosterically modulate catalytic activity; this has implications for the mechanisms by which individual proteins process chemical signals. To investigate these hypotheses, we propose NMR investigations of dynamics-activity relationships in a model protein, human Pin1. Pin1 is a mitotic regulator consisting of a docking module (WW domain) flexibly linked to a catalytic module (isomerase domain), and is a current cancer target. Its robust biochemical properties make it an excellent model system for exploring fundamental properties of modular proteins. Investigations will use full-length Pin1, its isolated domains, and known Pin1 substrates/inhibitors. PUBLIC HEALTH RELEVANCE This proposal describes studies of a model system to understand how intrinsic protein dynamics enable biological networks to maintain cell survival and growth. The proposed research will provide new insights into the molecular origins of disease.