Monolayers to Bilayers to Membranes

9603092麦康奈尔这项研究试图研究脂质双层膜中可能的液-液相分离，以及它们在生物膜功能中的可能作用。解决这些问题的方法在很大程度上依赖于本实验室先前在脂类单层膜中液-液相分离方面的发现。液-液相分离(及其临界点性质)的兴趣源于它们在生物膜中的可能作用，包括膜融合、形状、跨膜不对称性以及对脂质组成的酶调节。这项工作的一个主要挑战是明确地证明在脂质双层膜中存在一个从一个液体到两个液体的相变。第二个挑战是研究这种转变在生物膜脂组成调节中对物理或化学因素(如温度或激素)做出反应的可能性。这些研究使用的技术在很大程度上依赖于荧光显微镜。围绕活细胞的膜非常像一种非常薄的二维液体。这种液体是相当复杂的，由多种脂类分子组成，这些分子共同形成了这个二维膜。有许多实验证据表明，这些膜的物理性质和化学成分在活细胞中受到仔细的调控，但对这些性质之间的关系以及这些性质在细胞功能中的作用知之甚少。目的是找出这些膜液体中是否存在液-液相分离，以及它们是否具有重要的生物学功能。

9603092 McConnell This research seeks to study putative liquid-liquid phase separations in lipid bilayer membranes, and their possible role in the function of biological membranes. The approach to these problems relies heavily on the previous finding in this laboratory of liquid-liquid phase separations in lipid monolayer membranes. The interest in liquid-liquid phase separations (along with their critical point properties) stems from their possible role in biological membranes, including membrane fusion, shape, trans membrane asymmetries, as well as enzymatic regulation of lipid composition. A major challenge in this work is to demonstrate unequivocally a one liquid to two liquid phase transition in a lipid bilayer membrane. A second challenge is to investigate the possibility that such transitions play a role in the regulation of lipid composition of biological membranes in response to physical or chemical factors (e.g., temperature or hormones). The techniques to be used in these studies rely heavily on fluorescence microscopy. The membrane that surrounds a living cell is very much like a very thin, two dimensional liquid. This liquid is quite complex being composed of many sorts of lipid molecules that together form this two-dimensional membrane. There is much experimental evidence that the physical properties and chemical compositions of these membranes are carefully regulated in living cells, but the relationship between the physical and chemical properties is very poorly understood, as is the role of these properties in the function of cells. The goal is to find out if liquid-liquid phase separations exist in these membrane liquids, and if they serve important biological functions.