Le Varlet B, Staquet M J, Dezutter-Dambuyant C, Gaucherand M, Schmitt D
INSERM U 209, Hôpital Edouard Herriot, Lyon, France.
J Dermatol Sci. 1991 Jul;2(4):287-99. doi: 10.1016/0923-1811(91)90053-z.
The Very Late Activation (VLA) antigen family is involved in cell-extracellular matrix interactions and consists of six heterodimeric cell surface receptors with a common beta 1 and a variable alpha subunit. Using a panel of specific antibodies, we showed that human epidermal basal cells expressed VLA-2, VLA-3 and VLA-6 but failed to express VLA-4. Their functional roles were investigated and VLA-2 appeared as a specific receptor for type IV collagen and also as a laminin receptor. VLA-3 appeared as a receptor for fibronectin and laminin and to a lesser extent as a type I collagen receptor. VLA-6 appeared as a specific receptor for laminin. It also appeared that the VLA-alpha subunit specifically mediates the recognition of ligand but the beta 1 subunit is also involved in adhesion and that both subunits have a synergistic influence. Immunoprecipitation analyses confirmed that VLA-2, VLA-3 and VLA-6 were expressed by basal keratinocytes. Endocytosis of VLA-2 and VLA-3 was observed involving coated vesicles and endosomes that are structures characteristic of a receptor-mediated pathway. These findings provide first evidence that normal human basal keratinocytes are able of endocytosis mediated by receptors. Taken together, these results indicate that multiple VLA receptors function in combination to mediate epidermal basal cell adhesion to extracellular matrix.
极晚期活化（VLA）抗原家族参与细胞与细胞外基质的相互作用，由六个异二聚体细胞表面受体组成，具有共同的β1亚基和可变的α亚基。我们使用一组特异性抗体表明，人表皮基底细胞表达VLA-2、VLA-3和VLA-6，但不表达VLA-4。我们研究了它们的功能作用，VLA-2表现为IV型胶原的特异性受体，也是层粘连蛋白受体。VLA-3表现为纤连蛋白和层粘连蛋白的受体，在较小程度上是I型胶原受体。VLA-6表现为层粘连蛋白的特异性受体。还发现VLA-α亚基特异性介导配体的识别，但β1亚基也参与黏附，且两个亚基具有协同作用。免疫沉淀分析证实基底角质形成细胞表达VLA-2、VLA-3和VLA-6。观察到VLA-2和VLA-3的内吞作用涉及有被小泡和内体，这些是受体介导途径的特征性结构。这些发现首次证明正常人基底角质形成细胞能够进行受体介导的内吞作用。综上所述，这些结果表明多种VLA受体共同发挥作用，介导表皮基底细胞与细胞外基质的黏附。
