Fast Force Loading Disrupts Molecular Binding Stability in Human and Mouse Cell Adhesions.
Fast Force Loading Disrupts Molecular Binding Stability in Human and Mouse Cell Adhesions.
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DOI：
10.32604/mcb.2019.07267
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发表时间：
2019-01-01
期刊：
影响因子：
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通讯作者：
Zhu, Cheng
中科院分区：
文献类型：
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作者：
Chen, Yunfeng;Liao, Jiexi;Zhu, Cheng
力在细胞粘附和机械信号传导中起关键作用，部分通过调节解离速率，即，受体-配体键的解离速率。然而，这种调节的机制仍然难以捉摸。作为该领域的一个有争议的话题，当测量同一分子系统的“解离速率与力”关系时，不同的动态力谱（DFS）分析（即，力钳分析和力斜坡分析）经常产生矛盾的结果。这种差异阻碍了我们对分子结合的进一步理解，并对现有的理论模型提出了质疑。在这项工作中，我们使用活细胞DFS技术，生物膜力探针，测量的单键解离在三个受体-配体系统，分别具有重要的功能，在血管和免疫系统：人血小板GPIalpha-VWF，小鼠T细胞受体-OVA肽：MHC，和小鼠血小板整合素α IIb β 3-纤维蛋白原。使用力钳和力斜坡测定平行，我们确定，力加载破坏的稳定性的分子键的速率依赖性的方式。这种破坏性效应是通过两种解离状态之间的键的转变实现的：更快的力加载诱导更多的键采用快速解离状态（并且更少地采用缓慢解离状态）。基于这一机理，建立了一个新的生物物理模型，该模型考虑了力的大小和加载速率的影响。值得注意的是，该模型在研究的所有三种分子系统中协调了两种测定的结果。我们的发现为理解力如何调节受体-配体相互作用提供了新的范式，并为正确使用DFS技术提供了指导。此外，我们的工作强调了使用不同DFS测定来回答细胞粘附和机械信号传导领域中的特定生物学问题的机会。
Force plays critical roles in cell adhesion and mechano-signaling, partially by regulating the dissociation rate, i.e., off-rate, of receptor-ligand bonds. However, the mechanism of such regulation still remains elusive. As a controversial topic of the field, when measuring the "off-rate vs. force" relation of the same molecular system, different dynamic force spectroscopy (DFS) assays (namely, force-clamp and force-ramp assays) often yield contradictive results. Such discrepancies hurdled our further understanding of molecular binding, and casted doubt on the existing theoretical models. In this work, we used a live-cell DFS technique, biomembrane force probe, to measure the single-bond dissociation in three receptor-ligand systems which respectively have important functions in vascular and immune systems: human platelet GPIbalpha-VWF, mouse T cell receptor-OVA peptide:MHC, and mouse platelet integrin alphaIIbbeta3-fibrinogen. Using force-clamp and force-ramp assays in parallel, we identified that the force loading disrupted the stability of molecular bonds in a rate-dependent manner. This disruptive effect was achieved by the transitioning of bonds between two dissociation states: faster force loading induces more bonds to adopt the fast-dissociating state (and less to adopt the slow-dissociating state). Based on this mechanism, a new biophysical model of bond dissociation was established which took into account the effects of both force magnitude and loading rate. Remarkably, this model reconciled the results from the two assays in all three molecular systems under study. Our discoveries provided a new paradigm for understanding how force regulates receptor-ligand interactions and a guideline for the proper use of DFS technologies. Furthermore, our work highlighted the opportunity of using different DFS assays to answer specific biological questions in the field of cell adhesion and mechano-signaling.