The interaction of plasma fibronectin with fibroblastic cells in suspension.
The interaction of plasma fibronectin with fibroblastic cells in suspension.
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DOI：
10.1016/s0021-9258(18)89291-2
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发表时间：
1985-04
期刊：
影响因子：
--
通讯作者：
S. K. Akiyama;K. Yamada
中科院分区：
文献类型：
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作者：
S. K. Akiyama;K. Yamada
我们研究了悬液中可溶性血浆[~3H]纤维连接蛋白与成纤维细胞的相互作用。还原甲基化标记的纤维连接蛋白在4、22和37℃的无血清介质中以时间依赖的方式与幼年仓鼠肾脏细胞结合，在22℃的12-15分钟内出现一半最大结合，结合是饱和的和可逆的。根据结合放射性的胰酶敏感性判断，至少90%的细胞相关纤维连接蛋白位于质膜外部。结合浓度依赖的Scatchard分析表明，即使在低浓度的纤维连接蛋白的输入浓度下，也存在单一类别的结合位点。每个细胞大约有5+/-1×10(5)个位点，表观解离常数为8.0+/-0.5×10(-7)M；因此，可溶性纤维连接蛋白与这些细胞的结合具有中等亲和力。这种假定的成纤维细胞纤维连接蛋白受体在生理浓度的二价阳离子存在时对胰酶具有抵抗力，但在5 mM EDTA存在时对胰酶敏感。0.1 mg/ml未标记纤维连接蛋白可抑制60~80%的结合，1 mg/ml纯化的75 kDa纤维连接蛋白细胞结合域抑制95%，而1 mg/ml 44 kDa胶原结合域或5 mg/ml卵清蛋白不影响[~3H]纤维连接蛋白的结合。本研究中确定的结合参数进一步定义了成纤维细胞-表面纤维连接蛋白受体。
We have examined the interaction of soluble plasma [3H]fibronectin with fibroblastic cells in suspension. Fibronectin labeled by reductive methylation binds to baby hamster kidney cells in serum-free medium in a time-dependent manner at 4, 22, and 37 degrees C, with half-maximal binding occurring in 12-15 min at 22 degrees C. The binding is saturable and reversible. At least 90% of the cell-associated fibronectin is external to the plasma membrane, as judged by trypsin susceptibility of the bound radioactivity. Scatchard analysis of the concentration dependence of binding indicates the presence of a single class of binding sites, even at low input concentrations of fibronectin. There are approximately 5 +/- 1 X 10(5) sites/cell with an apparent dissociation constant of 8.0 +/- 0.5 X 10(-7) M; thus, the binding of soluble fibronectin to these cells is of moderate affinity. This putative fibroblast fibronectin receptor is resistant to trypsin in the presence of physiological concentrations of divalent cations but is susceptible to trypsin in the presence of 5 mM EDTA. Binding of 0.1 mg/ml [3H]fibronectin is 60-80% inhibited by 8 mg/ml unlabeled fibronectin and 95% inhibited by 1 mg/ml purified 75-kDa fibronectin cell-binding domain, but is unaffected by 1 mg/ml 44-kDa collagen-binding domain or 5 mg/ml ovalbumin. The binding parameters determined in this study further define the fibroblast cell-surface fibronectin receptor.