van Belzen N, Rijken P J, Hage W J, de Laat S W, Verkleij A J, Boonstra J
Department of Molecular Cell Biology, University of Utrecht, the Netherlands.
J Cell Physiol. 1988 Mar;134(3):413-20. doi: 10.1002/jcp.1041340312.
Several observations have indicated that clustering of growth factor receptors plays an important role in the action of growth factors. In this investigation, we have used the label fracture method to study the effects of epidermal growth factor (EGF) on the lateral distribution of its receptors in A431 epidermoid carcinoma cells. This method allows a direct visualization of immunogold-labeled plasma membrane receptors on ultrastructural level and in addition permits an quantitative analysis of their lateral distribution. EGF receptors were immunogold-labeled according to standard procedures with the monoclonal anti-EGF receptor antibody 2E9 (IgG1), which binds to the EGF receptor in a 1:1 ratio. In the absence of EGF, EGF receptors located on the surface of A431 cells were found to be clustered, as deduced from Poisson variance analysis (p less than 0.001). Following treatment of A431 cells with EGF, receptor clustering increased rapidly, reaching the maximum within 10 min. Maximal clustering was maintained for 1 h, after which the lateral distribution of receptors returned to the control situation within another hour.
多项观察结果表明，生长因子受体的聚集在生长因子的作用中起着重要作用。在本研究中，我们使用标记断裂法研究表皮生长因子（EGF）对其受体在A431表皮样癌细胞中侧向分布的影响。该方法能够在超微结构水平上直接观察免疫金标记的质膜受体，此外还能对其侧向分布进行定量分析。按照标准程序，用单克隆抗EGF受体抗体2E9（IgG1）对EGF受体进行免疫金标记，该抗体与EGF受体以1:1的比例结合。在没有EGF的情况下，通过泊松方差分析推断（p小于0.001），发现位于A431细胞表面的EGF受体是聚集的。用EGF处理A431细胞后，受体聚集迅速增加，在10分钟内达到最大值。最大聚集状态维持1小时，之后受体的侧向分布在另一小时内恢复到对照状态。
