Stallcup W B
Cancer Research Center, La Jolla Cancer Research Foundation, California 92037.
Exp Cell Res. 1988 Jul;177(1):90-102. doi: 10.1016/0014-4827(88)90027-4.
We have used a rat neural cell line, B65, to investigate the relative contributions of gangliosides and glycoprotein receptors in adhesion to fibronectin. Monoclonal antibodies against two neuroectoderm-associated gangliosides, D1.1 and GD3, inhibit the rate of B65 attachment to fibronectin, suggesting that these gangliosides are involved in the adhesion process. Adhesion to fibronectin is not affected by a third monoclonal antibody against a separate, unidentified cell-surface component of B65 cells. Furthermore, B65 cells lacking D1.1 adhere to fibronectin at a slower rate than B65 cells that express D1.1. The involvement of glycoprotein receptors in adhesion is demonstrated by the ability of antibodies against human fibronectin receptor to inhibit B65 attachment to fibronectin. In addition, adhesion is blocked by a hexapeptide containing the Arg-Gly-Asp fibronectin sequence which is necessary for binding to the receptor. Trypsin treatment of B65 cells in the absence of divalent cations results in proteolysis of the fibronectin receptor with an accompanying loss of ability of the cells to attach to fibronectin. D1.1 and GD3 expression is not affected by this trypsinization, indicating that the gangliosides alone are incapable of mediating attachment. The glycoprotein receptors must be primarily responsible for adhesion to fibronectin with the gangliosides playing a secondary role as enhancers or modulators.
我们使用了一种大鼠神经细胞系B65，来研究神经节苷脂和糖蛋白受体在与纤连蛋白黏附中的相对作用。针对两种与神经外胚层相关的神经节苷脂D1.1和GD3的单克隆抗体，可抑制B65细胞黏附到纤连蛋白的速率，这表明这些神经节苷脂参与了黏附过程。针对B65细胞另一种未明确的细胞表面成分的第三种单克隆抗体，并不影响细胞与纤连蛋白的黏附。此外，缺乏D1.1的B65细胞比表达D1.1的B65细胞黏附到纤连蛋白的速率更慢。抗人纤连蛋白受体抗体能够抑制B65细胞与纤连蛋白的黏附，这证明了糖蛋白受体参与了黏附过程。此外，含有精氨酸-甘氨酸-天冬氨酸纤连蛋白序列的六肽可阻断黏附，该序列对于与受体结合是必需的。在没有二价阳离子的情况下，用胰蛋白酶处理B65细胞会导致纤连蛋白受体的蛋白水解，同时细胞黏附到纤连蛋白的能力丧失。这种胰蛋白酶处理并不影响D1.1和GD3的表达，这表明仅神经节苷脂无法介导黏附。糖蛋白受体必定是细胞黏附到纤连蛋白的主要原因，而神经节苷脂作为增强剂或调节剂起次要作用。
