Lander A D, Fujii D K, Reichardt L F
J Cell Biol. 1985 Sep;101(3):898-913. doi: 10.1083/jcb.101.3.898.
When culture medium, conditioned by any of several cell types, is applied to a polycationic substratum, a substance is adsorbed that causes neurons cultured on that substratum to extend processes (neurites) rapidly and profusely. We have purified the factor responsible for this effect from medium conditioned by bovine corneal endothelial cells, and have shown that it is composed of the glycoprotein laminin and two associated laminin-binding molecules: a sulfated protein known as entactin, and a large heparan sulfate proteoglycan. Of these molecules, only laminin was found to be present throughout the purification in all fractions possessing neurite outgrowth-promoting activity and absent from all fractions lacking activity. Laminin, purified from other sources, has been shown previously to promote extensive outgrowth by cultured neurons. These and other data presented here support the conclusion that laminin is responsible for the neurite outgrowth-promoting activity of the conditioned medium factor. Evidence is also presented that the association of a proteoglycan with laminin promotes efficient attachment of laminin to polycationic substrata, particularly in the presence of competing molecules.
当用几种细胞类型中的任何一种所条件化的培养基应用于聚阳离子基质时，会吸附一种物质，该物质会使在该基质上培养的神经元迅速且大量地伸出突起（神经突）。我们已经从牛角膜内皮细胞所条件化的培养基中纯化出了负责这种效应的因子，并表明它由糖蛋白层粘连蛋白和两个相关的层粘连蛋白结合分子组成：一种称为巢蛋白的硫酸化蛋白，以及一种大型硫酸乙酰肝素蛋白聚糖。在这些分子中，仅发现层粘连蛋白在整个纯化过程中存在于所有具有促进神经突生长活性的级分中，而在所有缺乏活性的级分中不存在。先前已表明，从其他来源纯化的层粘连蛋白可促进培养的神经元广泛生长。此处呈现的这些及其他数据支持以下结论：层粘连蛋白负责条件化培养基因子的促进神经突生长活性。还提供了证据表明蛋白聚糖与层粘连蛋白的结合促进了层粘连蛋白与聚阳离子基质的有效附着，特别是在存在竞争分子的情况下。
