Sondermann H, Dogic D, Pesch M, Aumailley M
Institut II für Biochemie, Faculty of Medicine, Cologne, Germany.
Cell Adhes Commun. 1999;7(1):43-56. doi: 10.3109/15419069909034391.
Cellular interactions with the extracellular matrix determine to a large extent cell behavior, including cell migration. These interactions take place at specialized cellular structures, the focal adhesions, which have a substrate-specific morphology. To determine the molecular and functional relevance of this observation, the composition of isolated focal adhesions developed by fibroblasts adhering to fibronectin or laminin-1 was analyzed by indirect immunofluorescence and immunoblotting with or without stabilization of the structures by cross-linking. In the absence of cross-linking, integrins, talin, vinculin and, to a lower extent, paxillin remained associated with the focal adhesions formed on both substrates, indicating a tight association of these proteins with the extracellular matrix support. By contrast, alpha-actinin, FAK, and actin were apparently loosely maintained within focal adhesions and were found associated to these structures only after stabilization by cross-linking. Interestingly, although both substrates induced clustering and aggregation of all these proteins, their relative concentration, with the exception of alpha-actinin, was lower within the focal adhesions formed on laminin-1 than in those formed on fibronectin. Moreover, as assessed in migration assays, the locomotory speed of fibroblasts was higher on laminin-1 than on fibronectin. Altogether these results indicate that integrins involved in cellular interactions with fibronectin or laminin-1 trigger the formation of focal adhesion structures which differ by molecular organization, concentration in several adhesion plaque components, and function.
细胞与细胞外基质的相互作用在很大程度上决定了细胞行为，包括细胞迁移。这些相互作用发生在特殊的细胞结构——粘着斑上，粘着斑具有底物特异性形态。为了确定这一观察结果的分子和功能相关性，通过间接免疫荧光和免疫印迹分析了成纤维细胞粘附于纤连蛋白或层粘连蛋白-1时形成的分离粘着斑的组成，同时通过交联对结构进行稳定或不稳定处理。在没有交联的情况下，整合素、踝蛋白、纽蛋白以及较低程度的桩蛋白仍与在两种底物上形成的粘着斑相关联，表明这些蛋白质与细胞外基质支架紧密结合。相比之下，α-辅肌动蛋白、粘着斑激酶和肌动蛋白在粘着斑内的维持明显较为松散，仅在通过交联稳定后才与这些结构相关联。有趣的是，尽管两种底物都诱导了所有这些蛋白质的聚集，但除α-辅肌动蛋白外，它们在层粘连蛋白-1上形成的粘着斑中的相对浓度低于在纤连蛋白上形成的粘着斑。此外，在迁移试验中评估发现，成纤维细胞在层粘连蛋白-1上的运动速度高于在纤连蛋白上。总之，这些结果表明，参与细胞与纤连蛋白或层粘连蛋白-1相互作用的整合素触发了粘着斑结构的形成，这些粘着斑在分子组织、几种粘着斑成分的浓度和功能方面存在差异。
