Molecular basis of recognition in the Immunological Synapse

摘要 分泌型和细胞表面定位的免疫球蛋白超家族蛋白(‘细胞外IgSFs’)是 一类重要的蛋白质，包括已证实的治疗自身免疫性疾病和癌症的靶点。 人类蛋白质组包含约500个胞外IgSFs，这是最大的细胞表面分子超家族， 通过免疫中特异性的IgSF：IgSF相互作用，有助于调节先天免疫和获得性免疫。 “突触”形成于抗原提呈细胞和T细胞之间。 我们的长期目标是了解免疫突触中相互作用的分子基础。这 需要绘制大量未注释的IgSFs之间的受体-配体相互作用图，并获得 洞察这些相互作用的特殊性。随后，我们计划利用我们新获得的见解 重新设计蛋白质界面以获得特异性，既是为了产生新的试剂，反过来又可以进一步 询问免疫突触内的调节机制，并建立潜在的新药先导 这可以合理地调节疾病的免疫反应。 在这一应用中，我们将进一步发展我们的蛋白质设计辅助药效团方法，ProtLID 并利用它来识别免疫突触中的同源伙伴，并设计特定的接口。我们 还将探索将计算和实验蛋白质工程技术协同结合。我们 将开发一种跨学科的方法，其中以计算设计的、基于残留物的药效团 受体-配基界面的描述用于指导后续噬菌体展示中的文库设计 实验，允许对工程构造进行有效探索。我们所有的计算结果都将 随后进行体外生化和基于细胞的实验验证。 这些研究将直接扩展目前免疫中受体-配体对的知识库。 突触并产生突变分子，具有改变的亲和力和选择性，用于治疗应用。

Abstract Secreted and cell-surface-localized Immunoglobulin Superfamily proteins (‘extracellular IgSFs’) are important class of proteins, which includes proven targets for the treatment of autoimmune diseases and cancer. The human proteome contains ~500 extracellular IgSFs, the largest superfamily of cell surface molecules that contribute to the regulation of innate and adaptive immunity, via specific IgSF:IgSF interactions at the ‘Immune Synapse” formed between antigen-presenting cells and T-cells. Our long-term goal is to understand the molecular basis of interactions in the immune synapse. This requires the mapping of receptor-ligand interactions among the vast number of un-annotated IgSFs, and to gain insight about the specificity of these interactions. Subsequently, we plan to leverage our newly-gained insights into redesigning protein interfaces for specificity, both in order to generate new reagents that in turn can further interrogate the regulatory mechanisms within the immune synapse, and to establish potential new drug leads that can rationally modulate the immune response in diseases. In this application we will further develop our protein design-aided pharmacophore approach, ProtLID and utilize it for identifying cognate partners in the immune synapse, and for designing specific interfaces. We will also explore to synergisticly combine computational and experimental protein engineering techniques. We will develop an interdisciplinary approach where computationally designed, residue-based pharmacophore descriptions of the receptor-ligand interface are used to direct the library design in subsequent phage display experiments, allowing for the effective exploration of engineered constructs. All our computational results will be followed up with in vitro biochemical and cell-based experimental validation. These studies will directly expand the current knowledgebase of receptor-ligand pairs in the immune synapse and yield mutant molecules, with altered affinities and selectivities for therapeutic applications.