Configurational and internal dynamics of protein-protein complexes

描述(申请人提供)：这个拟议的项目寻求发展最近的范例，即蛋白质复合体可以是多构型的，如果不是高度动态的实体的话。需要了解这种动态复合体的生物物理和功能特征。我们选择了含有Eph-家族SAM结构域的杂二聚体配合物作为例子。SAM结构域很重要，因为它们存在于200多种人类蛋白质中，最明显的是在人类Eph受体酪氨酸激酶的所有14个成员中。这些受体在神经系统和心血管系统的发育中发挥作用，最近的研究表明，EphA2的SAM结构域在各种人类肿瘤和白内障中都发生了突变，这两者都与EphA2的失调有关。然而，EphA2 SAM结构域正常和异常功能的分子基础尚不清楚。我们将采用生物物理、计算和细胞生物学的三管齐下的方法，表征EPHA1-SHIP2和EphA2-SHIP2 SAM：SAM络合物的多构型特征。此外，我们将研究肿瘤相关突变如何不仅影响蛋白质的折叠、稳定性和聚集，而且可能通过改变SAM结构域与蛋白质的相互作用 SAM结构域的构型和内部动力学。我们将以同样的方式研究特定酪氨酸磷酸化的影响，揭示这些重要的翻译后修饰的分子基础。与Eph相关的SAM结构域的构象动力学和蛋白质-蛋白质相互作用的研究改变了我们对该结构域的正常和疾病功能的看法。从这项基础科学研究中获得的知识将作为其他动态蛋白质复合体的通用模型。此外，所获得的见解可能最终导致诊断和治疗试剂的设计。

DESCRIPTION (provided by applicant): This proposed project seeks to develop the recent paradigm that protein complexes can be multi-configurational, if not highly dynamic entities. The biophysical and functional features of such dynamic complexes need to be understood. We chose heterodimer complexes involving Eph-family SAM domains as an example. SAM domains are important as they occur in over 200 human proteins, most notably in all 14 members of human Eph receptor tyrosine kinases. These receptors function in the development of the nervous and cardiovascular systems, and recent studies have shown that the SAM domain of EphA2 is mutated in a variety of human tumors as well as cataract, both linked to EphA2 dysregulation. However, the molecular basis of the normal and abnormal function of EphA2 SAM domain is not yet understood. Using a three-pronged approach, involving biophysical, computational and cell biology methods we will characterize the multi-configurational features of EphA1-SHIP2 and EphA2-SHIP2 SAM:SAM complexes. Furthermore, we will study how tumor associated mutations affect not just protein folding, stability and aggregation, but likely affect SAM domain-protein interactions via alterations of the configurational and internal dynamics of SAM domains. We will study the effect of specific tyrosine phosphorylation in the same manner, revealing the molecular basis of these functionally important posttranslational modifications. Investigations of Eph-related SAM domain conformational dynamics and protein-protein interactions have shifted our perspective on the normal and disease function of the domain. The knowledge obtained from this basic science research will serve as a general model for other dynamic protein complexes. Furthermore, the insights obtained, may eventually lead to the design of diagnostic and therapeutic agents.