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Abstract：
The spatial organization of cell membrane glycoproteins and glycolipids is critical for mediating the binding of ligands, receptors, and macromolecules on the plasma membrane. However, we currently do not have the methods to quantify the spatial heterogeneities of macromolecular crowding on live cell surfaces. In this work, we combine experiment and simulation to report crowding heterogeneities on reconstituted membranes and live cell membranes with nanometer spatial resolution. By quantifying the effective binding affinity of IgG monoclonal antibodies to engineered antigen sensors, we discover sharp gradients in crowding within a few nanometers of the crowded membrane surface. Our measurements on human cancer cells support the hypothesis that raft-like membrane domains exclude bulky membrane proteins and glycoproteins. Our facile and high-throughput method to quantify spatial crowding heterogeneities on live cell membranes may facilitate monoclonal antibody design and provide a mechanistic understanding of plasma membrane biophysical organization.
摘要：
细胞膜糖蛋白和糖脂的空间组织对于介导配体的结合至关重要，受体,和质膜上的大分子。然而,我们目前还没有量化活细胞表面大分子拥挤的空间异质性的方法。在这项工作中,我们将实验和模拟相结合，以纳米空间分辨率报告重组膜和活细胞膜上的拥挤异质性。通过量化IgG单克隆抗体对工程化抗原传感器的有效结合亲和力，我们在拥挤的膜表面的几纳米范围内发现了急剧的拥挤梯度。我们对人类癌细胞的测量支持以下假设：移植物样膜结构域排除了大体积的膜蛋白和糖蛋白。我们用于量化活细胞膜上空间拥挤异质性的简便高通量方法可能有助于单克隆抗体设计，并提供对质膜生物物理组织的机械理解。
