Molecular Insights into Membrane Curvature Recognition

摘要 我们建议确定膜曲率识别的结构和分子基础 以枯草芽孢杆菌(B.subtilis)中发现的一种高度保守的26个残基的多肽SpoVM为模型。 在前孔形成期间，SpoVM专门结合到前孔的凸面上，并启动 蛋白质外衣的组装。2009年，Ramamurthi等人提出。发现SpoVM使用膜几何结构 作为其最终亚细胞定位的终极线索。然而，目前尚不清楚纳米尺寸的SpoVM如何 (~40°对于假定的螺旋)能够识别微米大小的微曲表面 前孔。与目前认为SpoVM假设一个长而直的两亲性？螺旋和 在膜表面浅层缔合，我们发现SpoVM采用环-螺旋结构，即 深深地嵌入在膜中。这项建议旨在将研究扩展到类似的模型系统 为了阐明枯草杆菌前孔膜的曲率和脂类组成。 SpoVM膜曲率识别的分子机制。我们假设深度疏水 插入是SpoVM检测微小膜曲率的关键。在追求这些目标的同时，我们将利用 几何定义良好的球形支撑脂质双层作为弯曲膜的新模型和 发展了一种原位核磁共振方法来确定膜蛋白结构。 细胞膜的形状是一种保守的进化表型。膜的形状是 由蛋白质-脂和脂-脂相互作用产生和维持的。检测和检测 膜形状的重塑是许多基本细胞过程的一部分，例如内吞作用， 囊泡形成和蛋白质运输。了解细胞产生、维持和维持的分子机制 而膜几何的调节是生物学中的一个基本问题，它将开辟新的治疗方法 机遇。

Abstract We propose to determine the structural and molecular basis of membrane curvature recognition using SpoVM, a highly conserved 26-residue peptide found in Bacillus subtilis (B. subtilis), as a model. During forespore formation, SpoVM exclusively binds to the convex surface of the forespore and initiates the assembly of a protein coat. In 2009, Ramamurthi et al. discovered that SpoVM uses the membrane geometry as an ultimate cue for its final subcellular localization. However, it is unclear how the nanometer-sized SpoVM (~40 ¿ for a presumed ¿-helix) is able to recognize the slightly curved surface of the micrometer-sized forespore. Contrary to the current belief that SpoVM assumes a long straight amphipathic ¿-helix and shallowly associates at the membrane surface, we found that SpoVM adopts a loop-helix structure that is deeply embedded in the membrane. This proposal seeks to extend the study to model systems that are similar in curvature and lipid composition to the membrane of the B. subtilis forespore in order to elucidate the molecular mechanism of SpoVM membrane curvature recognition. We hypothesize that deep hydrophobic insertion is key for SpoVM to detect small membrane curvature. While pursuing these goals, we will exploit geometrically well-defined spherical supported lipid bilayers as a new model for the curved membrane and develop an in situ NMR approach for determining membrane protein structures. The shape of cellular membranes is a well-conserved evolutionary phenotype. Membrane shape is generated and maintained by the interplay of protein-lipid and lipid-lipid interactions. The detection and remodeling of membrane shapes are part of many essential cellular processes such as endocytosis, vesiculation and protein trafficking. Understanding the molecular mechanism for the generation, maintenance, and regulation of membrane geometry is a fundamental question in biology and will open up new therapeutic opportunities.