Dowrick P, Kenworthy P, McCann B, Warn R
School of Biological Sciences, University of East Anglia, Norwich/United Kingdom.
Eur J Cell Biol. 1993 Jun;61(1):44-53.
Treatment with hepatocyte growth factor/scatter factor (HGF/SF) rapidly induced the formation of conspicuous circular ruffles on the apical surfaces of two kidney cell lines, MDCK and PtK2. The ruffles were found to contain significant amounts of F-actin and myosin as judged by immunofluorescence microscopy. Time-lapse photomicroscopy demonstrated that the ruffles constrict, closing over, and were followed by the formation of phase bright structures. That these structures were macropinocytotic vesicles was confirmed using fluorescein isothiocyanate (FITC)-dextran as a marker for fluid uptake. It is hypothesized that the constriction of the ruffles followed by membrane fusion causes the vesicles to form. Treatment with suramin blocked both circular ruffle formation and scattering, suggesting that ligand binding was the causal agent for ruffle formation. The drugs amiloride and SITS (4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid) also completely inhibited ruffle formation, suggesting that ion transport was an early consequence of HGF/SF binding and that these transport effects had a major role in the cytoskeletal changes leading to circular ruffle formation. The appearance of macropinocytotic vesicles was also blocked by amiloride treatment. Surprisingly though, subsequent scattering was not blocked by amiloride treatment, although suramin and SITS both entirely inhibited scattering.
用肝细胞生长因子/分散因子（HGF/SF）处理可迅速诱导两种肾细胞系MDCK和PtK2的顶端表面形成明显的圆形褶皱。通过免疫荧光显微镜观察发现，这些褶皱含有大量的F-肌动蛋白和肌球蛋白。延时显微镜观察表明，褶皱会收缩、闭合，随后形成折光性增强的结构。使用异硫氰酸荧光素（FITC）-葡聚糖作为液体摄取的标志物，证实这些结构是巨吞饮小泡。据推测，褶皱收缩后膜融合导致小泡形成。用苏拉明处理可阻断圆形褶皱的形成和细胞分散，这表明配体结合是褶皱形成的起因。药物氨氯吡咪和SITS（4-乙酰氨基-4'-异硫氰酸基芪-2,2'-二磺酸）也完全抑制褶皱形成，这表明离子转运是HGF/SF结合的早期结果，并且这些转运效应在导致圆形褶皱形成的细胞骨架变化中起主要作用。氨氯吡咪处理也可阻断巨吞饮小泡的出现。然而，令人惊讶的是，尽管苏拉明和SITS都完全抑制细胞分散，但氨氯吡咪处理并未阻断随后的细胞分散。
