Mechanisms of Integrin Receptor Transmembrane Signaling

项目总结/摘要 我们的长期研究兴趣在于努力了解细胞表面受体的结构基础 跨膜信号传导和伴随的信息传递到细胞内蛋白质和来自细胞内蛋白质。 特别关注的是细胞粘附受体的整合素家族，这是不可或缺的， 脊椎动物的功能，并对血管系统的运作至关重要。 整联蛋白由两个非共价缔合的亚基组成，称为α和β，并且具有 它具有跨越细胞膜双向传递信号的非凡能力。为此， 其两个亚基的跨膜螺旋必须编码至少三种功能状态（无活性， 由内向外和由外向内信令）。然而，除了认识到， 跨膜螺旋伴随着跨膜信号，数据很少，特别是结构数据， 关于跨膜螺旋包装、倾斜和膜包埋，为了发现 细胞骨架蛋白talin与整合素β结合后， 细胞质尾，是跨细胞膜传输，我们的研究追求以下具体目标： (i)单体的结构、动力学和膜包埋的测定 每个整合素的跨膜螺旋？IIb和？3亚基。(ii)结构解析、相互作用 和异源二聚体整合素的膜包埋？IIb和？3个跨膜螺旋。（三） 塔林结合的后果评估？3、？IIb-？3跨膜结构， 相互作用和膜包埋。我们正在使用溶液核磁共振光谱来完成这些 目标.包含整联蛋白的肽？IIb-？产生3个跨膜尾和胞质尾 重组并在脂质双层模型膜中重构。整合素？IIb-？3个调解人 血小板聚集，因此是血栓形成的关键调节剂。有效控制，如果 适用，防止血栓，其病理表现导致心脏病发作和中风， 必须了解导致其形成的分子事件。因此，我们的研究有助于 了解血管系统内分子和细胞的相互作用，并将有助于 开发治疗血管疾病的药物和疗法。项目叙述 中风和心脏病发作是死亡的两个主要原因， 血管系统目前的建议提供了结构基础，了解一个关键的调解人， 印迹血小板聚集并将有助于通过药物提供对该过程的控制。

PROJECT SUMMARY/ABSTRACT Our long-term research interest lies in striving to understand the structural basis of cell surface receptor transmembrane signaling and the concomitant relay of information to and from intracellular proteins. Particular focus is placed on the integrin family of cell-adhesion receptors, which is indispensable for the functioning of vertebrates and is of central importance to the operation of the vascular system. Integrins consist of two non-covalently associated subunits, termed alpha and beta, and possess the remarkable ability to transmit signals bidirectionally across the cell membrane. To do so, the single transmembrane helices of their two subunits must encode at least three functional states (inactive, inside-out and outside-in signaling). However, aside from recognizing that a separation of the transmembrane helices accompanies transmembrane signaling, little data, in particular structural data, is available about transmembrane helix packing, tilt and membrane embedding. In an effort to discover how an activating signal, following the binding of the cytoskeletal protein talin to the integrin beta cytosolic tail, is transmitted across the cell membrane, our research pursues the following specific aims: (i) Determination of the structure, dynamics and membrane embedding of the monomeric transmembrane helix of each integrin ?IIb and ?3 subunit. (ii) Elucidation of the structure, interaction and membrane embedding of the heterodimeric integrin ?IIb and ?3 transmembrane helices. (iii) Evaluation of the consequences of talin binding to the ?3 and ?IIb-?3 transmembrane structure, interaction and membrane embedding. We are using solution NMR spectroscopy to accomplish these goals. Peptides encompassing the integrin ?IIb-?3 transmembrane and cytosolic tails are produced recombinantly and they are reconstituted in lipid bilayer model membranes. Integrin ?IIb-?3 mediates blood platelet aggregation and, as such, is a key regulator of thrombosis. To effectively control and, if applicable, prevent thrombi, whose pathological appearances lead to heart attack and stroke, the molecular events leading to their formation must be understood. Thus, our research contributes to the understanding of the interactions of molecules and cells within the vascular system, and will aid in the development of drugs and therapies to treat vascular diseases. PROJECT NARRATIVE Stroke and heart attack, two of the major causes of death, arise from pathological aberrations of the vascular system. The current proposal provides the structural basis for understanding a key mediator of blot platelet aggregation and will aid in providing control of this process by drugs.