Integrin-mediated adhesion regulates membrane order.
Integrin-mediated adhesion regulates membrane order.
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DOI：
10.1083/jcb.200603034
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发表时间：
2006-08-28
影响因子：
7.8
通讯作者：
Schwartz, Martin A
中科院分区：
文献类型：
--
作者：
Gaus, Katharina;Le Lay, Soazig;Balasubramanian, Nagaraj;Schwartz, Martin A
细胞膜中胆固醇依赖结构域（脂筏）的性质一直存在争议。由于整合素介导的细胞粘附和小窝蛋白都调节筏组件的运输，我们研究了粘附和小窝蛋白对膜秩序的影响。荧光探针Laurdan和双光子显微镜显示，局灶性粘连是高度有序的;事实上，它们比用霍乱毒素亚单位B（Ctx B）染色的小窝或结构域更有序。粘着斑处的膜顺序部分取决于Tyr 14处的小窝蛋白1的磷酸化，其定位于粘着斑。细胞从基质中分离触发膜顺序的快速，小窝蛋白独立的减少，随后是与CtxB染色结构域的内化相关的较慢的小窝蛋白依赖性减少。内吞的CtxB结构域也变得更加流动。因此，膜秩序高度依赖于小窝和局灶性粘连。这些结果表明，脂筏的性质赋予特定的蛋白质复合物的组装。局灶性粘连内的有序状态可能对这些部位的信号传导具有重要影响。
The properties of cholesterol-dependent domains (lipid rafts) in cell membranes have been controversial. Because integrin-mediated cell adhesion and caveolin both regulate trafficking of raft components, we investigated the effects of adhesion and caveolin on membrane order. The fluorescent probe Laurdan and two-photon microscopy revealed that focal adhesions are highly ordered; in fact, they are more ordered than caveolae or domains that stain with cholera toxin subunit B (CtxB). Membrane order at focal adhesion depends partly on phosphorylation of caveolin1 at Tyr14, which localizes to focal adhesions. Detachment of cells from the substratum triggers a rapid, caveolin-independent decrease in membrane order, followed by a slower, caveolin-dependent decrease that correlates with internalization of CtxB-stained domains. Endocytosed CtxB domains also become more fluid. Thus, membrane order is highly dependent on caveolae and focal adhesions. These results show that lipid raft properties are conferred by assembly of specific protein complexes. The ordered state within focal adhesions may have important consequences for signaling at these sites.