AbstractPhospholipids in biological membranes establish a chemical equilibrium between free phospholipids in the aqueous phase (CMC) and self‐assembled phospholipids in vesicles, keeping the CMC constant. The CMC is different for each phospholipid, depends on the amount of cholesterol, and, according to the lipid‐chaperone hypothesis, controls the interaction between free phospholipids and amyloidogenic proteins (such as amylin, amyloid‐β, and α‐synuclein, all of which are, respectively, associated with a different proteinopathy), which governs the formation of a toxic complex between free lipids and proteins that leads to membrane destruction. Here, we provide quantitative measurements of CMCs and bilayer stability of pure phospholipids, lipid rafts, and their mixture with cholesterol by fluorescence methods (using pyrene as a probe) and light scattering techniques (resonance Rayleigh scattering and fixed‐angle light scattering) performed on LUVs, as well as AFM to measure LUV dimensions. Also, we test the lipid‐chaperone hypothesis on human IAPP interacting with different mixture of POPC cholesterol. Stated the importance of CMC in membrane stability and protein aggregation processes, these results could be a starting point for the development of a quantitative kinetic model for the lipid chaperone hypothesis.

中文翻译：

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纯磷脂和脂筏及其与胆固醇混合物的临界胶束浓度测定

摘要生物膜中的磷脂在水相中的游离磷脂 (CMC) 和囊泡中的自组装磷脂之间建立化学平衡，从而保持 CMC 恒定。每种磷脂的 CMC 都不同，取决于胆固醇的量，并且根据脂质伴侣假说，CMC 控制游离磷脂和淀粉样蛋白（例如淀粉样蛋白、β 淀粉样蛋白和 α-突触核蛋白，所有这些蛋白）之间的相互作用。它们分别与不同的蛋白质病相关），其控制游离脂质和蛋白质之间有毒复合物的形成，从而导致膜破坏。在这里，我们通过荧光方法（使用芘作为探针）和光散射技术（共振瑞利散射和固定角光散射）对纯磷脂、脂筏及其与胆固醇的混合物的 CMC 和双层稳定性进行定量测量。 LUV 以及用于测量 LUV 尺寸的 AFM。此外，我们还测试了人类 IAPP 与不同 POPC 胆固醇混合物相互作用的脂质伴侣假说。阐述了 CMC 在膜稳定性和蛋白质聚集过程中的重要性，这些结果可能成为开发脂质伴侣假说定量动力学模型的起点。