Larjava H, Peltonen J, Akiyama S K, Yamada S S, Gralnick H R, Uitto J, Yamada K M
Membrane Biochemistry Section, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
J Cell Biol. 1990 Mar;110(3):803-15. doi: 10.1083/jcb.110.3.803.
We have examined the expression, localization, and function of beta 1 integrins on cultured human epidermal keratinocytes using polyclonal and monoclonal antibodies against the beta 1, alpha 2, alpha 3, and alpha 5 integrin subunits. The beta 1 polypeptide, common to all class 1 integrins, was localized primarily in areas of cell-cell contacts of cultured keratinocytes, as were alpha 2 and alpha 3 polypeptides, suggesting a possible role in cell-cell adhesion for these integrin polypeptides. In contrast, the fibronectin receptor alpha 5 subunit showed no such accumulations in regions of cell-cell contact but was more diffusely distributed in the keratinocyte plasma membrane, consistent with the absence of fibronectin at cell-cell contact sites. Colonies of cultured keratinocytes could be dissociated by treatment with monoclonal antibody specific to the beta 1 polypeptide. Such dissociation of cell-cell contacts also occurred under conditions where the monoclonal antibody had no effect on cell-substrate adhesion. Therefore, beta 1 integrin-dependent cell-cell adhesion can be inhibited without affecting other cell-adhesive interactions. Antibody treatment of keratinocytes maintained in either low (0.15 mM) or high (1.2 mM) CaCl2 also resulted in the loss of organization of intracellular F-actin filaments and beta 1 integrins, even when the anti-beta 1 monoclonal antibody had no dissociating effect on keratinocyte colonies at the higher calcium concentration. Our results indicate that beta 1 integrins play roles in the maintenance of cell-cell contacts between keratinocytes and in the organization of intracellular microfilaments. They suggest that in epithelial cells integrins can function in cell-cell interactions as well as in cell-substrate adhesion.
我们使用针对β1、α2、α3和α5整合素亚基的多克隆和单克隆抗体，研究了培养的人表皮角质形成细胞上β1整合素的表达、定位和功能。所有1类整合素共有的β1多肽主要定位于培养的角质形成细胞的细胞间接触区域，α2和α3多肽也是如此，这表明这些整合素多肽在细胞间黏附中可能发挥作用。相比之下，纤连蛋白受体α5亚基在细胞间接触区域没有这种聚集，而是更分散地分布在角质形成细胞质膜中，这与细胞间接触部位不存在纤连蛋白一致。培养的角质形成细胞集落可用针对β1多肽的单克隆抗体处理使其解离。在单克隆抗体对细胞-基质黏附无影响的条件下，细胞间接触也会发生这种解离。因此，β1整合素依赖性细胞间黏附可被抑制，而不影响其他细胞黏附相互作用。用抗体处理维持在低（0.15 mM）或高（1.2 mM）CaCl2浓度下的角质形成细胞，也会导致细胞内F-肌动蛋白丝和β1整合素的组织丧失，即使抗β1单克隆抗体在较高钙浓度下对角质形成细胞集落没有解离作用。我们的结果表明，β1整合素在维持角质形成细胞之间的细胞间接触以及细胞内微丝的组织中发挥作用。它们表明，在上皮细胞中，整合素可在细胞间相互作用以及细胞-基质黏附中发挥作用。
