Alonso M A, Millán J
Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, Cantoblanco, 28049-Madrid, Spain.
J Cell Sci. 2001 Nov;114(Pt 22):3957-65. doi: 10.1242/jcs.114.22.3957.
Combinatorial association of different lipid species generates microheterogeneity in biological membranes. The association of glycosphingolipids with cholesterol forms membrane microdomains--lipid rafts--that are involved in specialised pathways of protein/lipid transport and signalling. Lipid rafts are normally dispersed in cellular membranes and appear to require specialised machinery to reorganise them to operate. Caveolin-1 and MAL are members of two different protein families involved in reorganisation of lipid rafts for signalling and/or intracellular transport in epithelial cells. T cell activation induces a rapid compartmentalisation of signalling machinery into reorganised rafts that are used as platforms for the assembly of the signalling complex. Costimulatory molecules participate in this process by providing signals that mobilise raft lipids and proteins, and remodel the cytoskeleton to the contact site. As in epithelial cells, rafts are used also as vesicular carriers for membrane trafficking in T lymphocytes. Furthermore, there are potential similarities between the specialised protein machinery underlying raft-mediated processes in T lymphocytes and polarised epithelial cells.
不同脂质种类的组合关联在生物膜中产生微异质性。糖鞘脂与胆固醇的关联形成膜微区——脂筏——其参与蛋白质/脂质转运和信号传导的特定途径。脂筏通常分散在细胞膜中，似乎需要特殊机制来重新组织它们以发挥作用。小窝蛋白-1和MAL是参与上皮细胞中脂筏重排以进行信号传导和/或细胞内运输的两个不同蛋白质家族的成员。T细胞活化诱导信号传导机制快速分隔到重组的脂筏中，这些脂筏用作信号复合物组装的平台。共刺激分子通过提供动员脂筏脂质和蛋白质并将细胞骨架重塑至接触位点的信号来参与这一过程。与上皮细胞一样，脂筏在T淋巴细胞中也用作膜运输的囊泡载体。此外，T淋巴细胞和极化上皮细胞中脂筏介导过程背后的特殊蛋白质机制之间存在潜在的相似性。
