Stucture and Function of Membrane Rafts

膜筏的结构和功能

• 批准号: 7125252
• 负责人: DEBORAH Ann BROWN
• 金额: $ 9.31万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7125252
• 关键词: G protein; Golgi apparatus; apical membrane; biological signal transduction; caveolins; cell membrane; epithelium; fluorescence polarization; glycosphingolipids; laboratory rat; lipid structure; lipid transport; mass spectrometry; matrix assisted laser desorption ionization; membrane lipids; membrane proteins; membrane structure; molecular site; protein kinase; protein structure function; protein transport; tissue /cell culture

DESCRIPTION: (provided by applicant)Recent evidence suggests that lipids in biological membranes do not mix uniformly, but instead form microdomains or rafts of different lipid composition. Domains that are enriched in cholesterol and sphingolipids can be isolated from membranes by the fact that they are insoluble in detergents such as Triton X-100. These detergent-resistant membranes (DRMs) are in the liquid-ordered phase, a state in which lipid acyl chains are ordered, extended, and tightly packed. Lipids and proteins that prefer an ordered environment are enriched in DRMs and probably also in liquid-ordered phase rafts in intact cells. Rafts have recently been shown to play important roles in signal transduction, especially in hematopoietic cells such as T cells and basophils. In both cases, signaling in response to antigen binding requires the presence of rafts. Thus, a better understanding of raft structure has important implications for immune diseases and the allergic response. In this proposal, we will address three questions of raft structure. First, how does clustering of proteins and lipids expected to be in rafts affect raft structure and the interaction between raft components? Second, how do transmembrane proteins associate with rafts? Because of the tight packing of lipids in rafts membrane-spanning alpha helical protein segments would not be expected to fit well into this ordered environment. However, a few transmembrane proteins are specifically targeted to rafts. In some cases, acylation is required for targeting of these proteins to rafts. Other raft-associated transmembrane proteins are not acylated, and the mechanism of raft association is not known. We will examine members of each class. The third broad question is the role of lipid composition in raft formation. We will address three subquestions; how rafts form in the sphingolipid-poor inner leaflet of the plasma membrane, raft size, and the role of sterol structure in promoting raft formation. We will address all of these questions using several assays for raft structure, and for the affinity of individual components for them. We use detergent-insolubility and the fluorescence quenching assay that we have developed previously, and will work to develop additional detergent-free assays of raft structure. With these tools, we should obtain a better understanding of these important membrane specializations, and how the association of proteins with them is important in health and disease.

描述：（由申请人提供）最近的证据表明脂质 生物膜不会均匀混合，而是形成微区或 不同脂质组成的筏。富含胆固醇的结构域 鞘脂可以与膜隔离，因为它们是 不溶于Triton X-100等洗涤剂。这些防污剂 膜（DRMS）处于液相级相，脂质酰基 锁链，延伸并紧紧填充链条。脂质和蛋白质 更喜欢有序环境在DRM中丰富，也可能在 完整细胞中的液体订购相筏。筏最近已显示 在信号转导中起重要作用，尤其是在造血细胞中 例如T细胞和嗜碱性粒细胞。在这两种情况下，响应抗原的信号 结合需要筏的存在。因此，对筏的更好理解 结构对免疫疾病和过敏性具有重要意义 回复。在此提案中，我们将解决筏结构的三个问题。 首先，预期蛋白质和脂质的聚类如何 影响筏结构和筏分量之间的相互作用？第二，怎么 跨膜蛋白是否与筏相关？由于紧紧的包装 木筏中的脂质膜叠α螺旋蛋白片段不会是 预计将非常适合这个有序的环境。但是，一些 跨膜蛋白专门针对筏。在某些情况下， 将这些蛋白靶向筏是必需的。其他 与筏相关的跨膜蛋白不是酰化的，而机理的机理 筏关联尚不清楚。我们将检查每个班级的成员。第三 广泛的问题是脂质组成在筏形成中的作用。我们将 地址三个子问题；如何在鞘脂贫乏的内部形成筏 质膜，筏大小和固醇结构在 促进筏的形成。我们将使用几个 筏结构的测定，以及单个组件的亲和力 他们。我们使用洗涤剂 - 不加溶性和荧光淬灭测定法 我们以前已经开发了，并将努力开发其他 筏结构的无洗涤剂测定法。使用这些工具，我们应该获得 更好地理解这些重要的膜专长，以及如何 蛋白质与它们的关联在健康和疾病中很重要。