Mayor Satyajit, Rao Madan
National Centre for Biological Science (TIFR), UAS-GKVK Campus, GKVK PO, Bangalore 560 065, India.
Traffic. 2004 Apr;5(4):231-40. doi: 10.1111/j.1600-0854.2004.00172.x.
Rafts have been conceptualized as lateral heterogeneities in the organization of cholesterol and sphingolipids, endowed with sorting and signaling functions. In this review we critically examine evidence for the main tenet of the 'raft hypothesis', namely lipid-dependent segregation of specific membrane components in the plasma membrane. We suggest that conventional approaches to studying raft organization wherein membranes are treated as passive, thermally equilibrated systems are unlikely to provide an adequate framework to understand the mechanisms of raft-organization in vivo. An emerging view of raft organization is that it is spatio-temporally regulated at different scales by the cell. This argues that rafts must be defined by simultaneous observation of components involved in particular functions. Recent evidence from the study of glycosylphosphatidyl inositol-anchored proteins, a common raft-marker, supports this picture in which larger scale, more stable rafts are induced from preexisting small-scale lipid-dependent structures actively maintained by cellular processes.
筏被概念化为胆固醇和鞘脂组织中的横向异质性，具有分选和信号传导功能。在这篇综述中，我们批判性地审视了“筏假说”主要原则的证据，即质膜中特定膜成分的脂质依赖性分离。我们认为，传统的研究筏组织的方法，即将膜视为被动的、热平衡的系统，不太可能提供一个充分的框架来理解体内筏组织的机制。一种新兴的筏组织观点是，它在不同尺度上受到细胞的时空调节。这表明筏必须通过同时观察参与特定功能的成分来定义。来自糖基磷脂酰肌醇锚定蛋白（一种常见的筏标记物）研究的最新证据支持了这一图景，即更大规模、更稳定的筏是由细胞过程积极维持的先前存在的小规模脂质依赖性结构诱导形成的。
