Dynamic Strenghts of Leukoctye Adhesion Bonds

我们的长期目标是发展一个详细的生物物理理解白细胞粘附在 分子水平，将粘合强度与化学相互作用联系起来， 结合应力通过细胞膜传递到受体尾部之间的内部连接， 细胞的细胞结构，它可以影响特定的生化途径。我们目前的研究提供了 对白细胞粘附键的机械强度及其在力作用下的动力学的重要见解， (i)首先是唾液酸粘蛋白配体PSGL-1和选择素之间的相互作用， 附着于血管壁，（ii）其次是超级免疫球蛋白（IG）家族配体之间的相互作用 以及发出信号并稳定白细胞粘附从而使其迁移到组织中的整联蛋白。我们有 开发了新的方法，在超灵敏力探针的尖端上标记配体，并测试 与固定在微球上或表达在微球上的受体的单个键的机械强度 细胞开发一种令人兴奋的新方法，并建立了受体策略性改变的细胞系， 细胞骨架相互作用，本申请的主要目的是“在细胞内移动”，首先 确定细胞结构蛋白调节粘附机械强度的程度 复合物，然后确定这些连接在白细胞信号传导中发挥的机械作用， 对炎症和损伤部位的募集很重要的过程。这些研究旨在测试 三个假设假设：白细胞选择素和整合素相互作用具有功能特异性 在电池内部低应力条件下控制键形成和释放的机械设计， 表面接触，从而影响键增殖并决定初始粘附事件的命运。 假设：分子粘附复合物的机械强度由最薄弱的环节决定， 蛋白质相互作用的整个序列，从外部粘合键到内部键， 受体尾域的细胞结构。假设：整合素粘附的锚键 复杂的细胞结构是关键的机械效应器的“外-内”和“内-外”的信号转导， 白细胞，并代表调节粘附强度的重要反馈过程。

Our long-term objective is to develop a detailed biophysical understanding of leukocyte adhesion at the molecular level, relating adhesive bond strength to chemical interactions and establishing how adhesive bond stress is transmitted through the cell membrane to the interior connections between receptor tails and the cell cytostructure where it can impact specific biochemical pathways. Our current research has provided significant insight into the mechanical strengths of leukocyte adhesion bonds and their kinetics under force, (i) first for interactions between the sialo mucin ligand PSGL-1 and selectins that initiate leukocyte attachments to vessel walls, (ii) second for interactions between super immunoglobulin (Ig)family ligands and integrins that signal and stabilize leukocyte adhesion enabling emigration into tissues. We have developed novel methods to immobilize ligands on the tip of ultrasensitive force probes and test the mechanical strengths of individual bonds to receptors either immobilized on microspheres or expressed on cells. Exploiting an exciting new approach and established cell lines with strategic alterations in receptor- cytoskeletal interactions, the principal objective of this application is to "move inside the cell", first establishing the extent to which cytostructural proteins regulate the mechanical strength of an adhesion complex, and then determining the mechanical role that these linkages play in the leukocyte signalling processes important for recruitment to sites of inflammation and injury. The studies are designed to test three hypotheses. Hypothesis: leukocyte selectin and integrin interactions have function-specific mechanical designs that govern bond formation and release under conditions of low stress interior to a cell- surface contact, thereby impacting bond proliferation and determining the fate of the initial adhesion event. Hypothesis: mechanical strengths of molecular adhesion complexes are governed by the weakest link in entire sequence of protein interactions from the outside adhesive bond to the inside bonds that connect receptor-tail domains to the cell cytostructure. Hypothesis: the linkages that anchor an integrin adhesion complex to the cell structure are key mechanical effectors of "outside-in" and "inside-out" signaling in leukocytes and represent an important feed-back process to regulate adhesion strength.