Pfeiffer J R, Oliver J M, Berlin R D
Nature. 1980 Aug 14;286(5774):727-9. doi: 10.1038/286727a0.
The internalization of a wide range of biologically significant macromolecules, particularly low density lipoproteins (LDL) and proteins such as alpha 2-macroglobulin and epidermal growth factor, occurs primarily through characteristic, bristle-coated indentations of the cell surface known as coated pits. Current interest has focused on the topographical relationship between surface receptors for these ligands and the coated pits. We establish here that coated pits are themselves distributed non-randomly on the J774.2 mouse macrophage cell surface. Morphometric and statistical analyses of cell profiles in electron micrographs indicate two levels of asymmetry; in all cells, pits are clustered; after colchicine treatment they accumulate over a microvillous protuberance that develops at one pole of the cell. This topographical heterogeneity suggests a new level at which cellular responses to growth substances and hormones may be regulated.
多种具有生物学意义的大分子的内化，尤其是低密度脂蛋白（LDL）以及诸如α2-巨球蛋白和表皮生长因子等蛋白质，主要通过细胞表面特征性的、被覆有纤毛的凹陷（即被覆小窝）发生。目前的研究兴趣集中在这些配体的表面受体与被覆小窝之间的拓扑关系上。我们在此证实，被覆小窝本身在J774.2小鼠巨噬细胞表面呈非随机分布。电子显微镜图像中细胞轮廓的形态计量学和统计分析表明存在两个不对称水平；在所有细胞中，小窝成簇分布；秋水仙碱处理后，它们聚集在细胞一极形成的微绒毛突起上。这种拓扑异质性提示了细胞对生长物质和激素的反应可能被调节的一个新层面。
