Influence of receptor lateral mobility on adhesion strengthening between membranes containing LFA-3 and CD2.
Influence of receptor lateral mobility on adhesion strengthening between membranes containing LFA-3 and CD2.
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DOI：
10.1083/jcb.115.1.245
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发表时间：
1991-10
影响因子：
7.8
通讯作者：
Springer, T A
中科院分区：
文献类型：
--
作者：
Chan, P Y;Lawrence, M B;Dustin, M L;Ferguson, L M;Golan, D E;Springer, T A
我们已经使用了玻璃支撑的平面膜的体外模型系统，研究膜结合受体的横向流动性对细胞粘附的影响。用粘附分子淋巴细胞功能相关抗原3（LFA-3）的两种锚定异构体重建卵磷脂（PC）双层。糖基磷脂酰肌醇（GPI）锚定的LFA-3的扩散系数接近磷脂的双层，而跨膜（TM）锚定的异构体的LFA-3是固定的。静态和层流测定用于定量表达反受体CD 2的T淋巴瘤细胞系Jurkat的脂质双层的粘附强度。细胞粘附依赖于LFA-3密度，并且在含有GPI同种型的膜上比TM同种型更有效。动力学测量证明了接触时间对在较低位点密度（25-50位点/微米2）下与GPI同种型的粘附强度的影响，表明LFA-3的移动性在粘附增强中是重要的。在更高的位点密度（1,500个位点/微米2）和更长的接触时间（20分钟），Jurkat细胞与LFA-3的TM和GPI同种型的结合显示出相同的粘附强度，尽管GPI同种型的粘附强度比TM同种型快两倍。在5 ° C下Jurkat细胞上的CD 2迁移率的降低大大降低了与LFA-3的TM同种型的粘附增强的速率，导致两种LFA-3同种型之间的差异为30倍。我们的研究结果表明，膜受体和其膜结合的反受体的能力，横向扩散增强细胞粘附，通过允许在细胞接触面积的配体的积累，并通过增加受体-配体键形成的速率。
We have used an in vitro model system of glass-supported planar membranes to study the effects of lateral mobility of membrane-bound receptors on cell adhesion. Egg phosphatidylcholine (PC) bilayers were reconstituted with two anchorage isoforms of the adhesion molecule lymphocyte function-associated antigen 3 (LFA-3). The diffusion coefficient of glycosyl phosphatidylinositol (GPI)-anchored LFA-3 approached that of phospholipids in the bilayers, whereas the transmembrane (TM)-anchored isoform of LFA-3 was immobile. Both static and laminar flow assays were used to quantify the strength of adherence to the lipid bilayers of the T lymphoma cell line Jurkat that expresses the counter-receptor CD2. Cell adhesion was dependent on LFA-3 density and was more efficient on membranes containing the GPI isoform than the TM isoform. Kinetic measurements demonstrated an influence of contact time on the strength of adhesion to the GPI isoform at lower site densities (25-50 sites/microns2), showing that the mobility of LFA-3 is important in adhesion strengthening. At higher site densities (1,500 sites/microns2) and longer contact times (20 min), Jurkat cell binding to the TM and GPI isoforms of LFA-3 showed equivalent adhesion strengths, although adhesion strength of the GPI isoform developed twofold more rapidly than the TM isoform. Reduction of CD2 mobility on Jurkat cells at 5 degrees C greatly decreased the rate of adhesion strengthening with the TM isoform of LFA-3, resulting in a 30-fold difference between the two LFA-3 isoforms. Our results demonstrate that the ability of a membrane receptor and its membrane-bound counter- receptor to diffuse laterally enhances cell adhesion both by allowing accumulation of ligands in the cell contact area and by increasing the rate of receptor-ligand bond formation.