Excellence in Research: Molecular mechanism of Tissue Factor encryption and decryption.

卓越研究：组织因子加密和解密的分子机制。

• 批准号: 2100878
• 负责人: Alexei Iakhiaev
• 金额: $ 44.83万
• 依托单位: Texas College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2100878&HistoricalAwards=false
• 关键词: Excellence; Research; Molecular; mechanism; Tissue

This project is focused on the regulation of activity of a membrane protein Tissue Factor (TF) that serves as a cofactor for enzymes that initiate cascade reactions of blood coagulation. TF is inactive or encrypted in normal conditions, while in conditions of tissue damage, TF is exposed to coagulation enzymes and is turned into an activated or decrypted state. The primary mechanism of TF decryption is determined by the changes in membrane phospholipids leading to high-affinity binding of coagulation enzymes to the membrane surface and the TF, located on the membrane. However, mechanisms of encryption and decryption related directly to TF are not known. This project, with the state-of-the-art computational resources of the UT System, will provide training for undergraduate HBCU students. Outcomes of this project will have societal impact by providing new details about critical molecules with impacts in cardiovascular diseases and roles in viral infections. This project will develop a model of TF encryption and decryption based on the dimerization of TF. The model proposes an equilibrium between TF monomers and dimers. Dimers can be formed by two TF molecules bound in alternate configurations to produce encrypted, partially active, and fully active decrypted structures. This equilibrium depends on the lipid environment whereby specific lipids can selectively stabilize encrypted or decrypted dimers. The project will create models composed of full-length TF and other members of the coagulation cascade (Factor VIIa and Factor Xa)inserted into lipid bilayers of different phospholipid compositions. Molecular dynamics (MD) simulations and molecular docking will be carried out with the TF dimer models. Extensive comparative analysis of MD trajectories will be performed to reveal amino acids and membrane lipids essential for stabilizing TF dimers in an encrypted or decrypted state. In addition, amino acid residues involved in selective phospholipid binding and stabilization of encrypted or decrypted dimers will be selected for experimental validation of their role in TF encryption or decryption using mutational analysis combined with functional activity assays.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目的重点是调节膜蛋白组织因子（TF）的活性，TF作为启动血液凝固级联反应的酶的辅因子。TF在正常情况下是无活性的或加密的，而在组织损伤的情况下，TF暴露于凝固酶并变成活化或解密状态。TF解密的主要机制由膜磷脂的变化决定，导致凝固酶与膜表面和位于膜上的TF的高亲和力结合。 然而，与TF直接相关的加密和解密机制尚不清楚。 这个项目，与UT系统的最先进的计算资源，将为本科HBCU学生提供培训。 该项目的成果将通过提供有关影响心血管疾病和病毒感染作用的关键分子的新细节来产生社会影响。 本计画将以TF二聚体为基础，发展一个TF加解密模型。该模型提出了TF单体和二聚体之间的平衡。二聚体可以由以交替构型结合的两个TF分子形成，以产生加密的、部分活性的和完全活性的解密结构。这种平衡取决于脂质环境，从而特定的脂质可以选择性地稳定加密或解密的二聚体。该项目将创建由全长TF和插入不同磷脂组成的脂质双层的凝血级联（因子VIIa和因子Xa）的其他成员组成的模型。分子动力学（MD）模拟和分子对接将进行TF二聚体模型。将进行MD轨迹的广泛比较分析，以揭示在加密或解密状态下稳定TF二聚体所必需的氨基酸和膜脂质。此外，参与选择性磷脂结合和稳定加密或解密二聚体的氨基酸残基将被选择用于实验验证其在TF加密或解密中的作用，使用突变分析结合功能活性测定。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。