Laminin fragment E8 mediates PC12 cell neurite outgrowth by binding to cell surface beta 1,4 galactosyltransferase.
Laminin fragment E8 mediates PC12 cell neurite outgrowth by binding to cell surface beta 1,4 galactosyltransferase.
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层粘连蛋白片段E8通过与细胞表面β1,4半乳糖基转移酶结合来介导PC12细胞神经突生长。
DOI：
10.1083/jcb.113.3.637
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发表时间：
1991-05
影响因子：
7.8
通讯作者：
Shur, B D
中科院分区：
文献类型：
--
作者：
Begovac, P C;Hall, D E;Shur, B D
许多细胞表面受体与不同的层粘连蛋白结构域结合，从而介导层粘连蛋白的多种生物活性。细胞表面β 1，4-半乳糖基转移酶（GalTase）作为这些层粘连蛋白受体之一发挥作用，促进间充质细胞迁移和PC 12细胞神经突在层粘连蛋白上生长。在这项研究中，层粘连蛋白内的GalTase结合位点被确定为E8片段，通过测定纯化的片段，并通过免疫沉淀和免疫印迹半乳糖基化层粘连蛋白使用E8反应性抗体。与完整的层粘连蛋白和其他层粘连蛋白片段相比，E8具有最高的GalTase结合活性，同时使用膜结合的和溶解的GalTase。更重要的是，片段E8的神经突促进活性被证明是依赖于其与GalTase的相互作用。预半乳糖基化纯化的E8消除了随后的GalTase结合，从而抑制了神经突的起始;对层粘连蛋白片段E1-4或E1的平行研究未能影响神经突的生长。此外，抗GalTase IgG抑制纯化的E8底物上的神经突起始;对照IgG没有影响。这些结果本地化的主要半乳糖苷酶结合结构域在层粘连蛋白片段E8，并证明E8的神经突促进活性依赖于其与半乳糖苷酶的相互作用。
A number of cell surface receptors bind to distinct laminin domains, thereby mediating laminin's diverse biological activities. Cell surface beta 1,4-galactosyltransferase (GalTase) functions as one of these laminin receptors, facilitating mesenchymal cell migration and PC12 cell neurite outgrowth on laminin. In this study, the GalTase binding site within laminin was identified as the E8 fragment by assaying purified fragments and by immunoprecipitating and immunoblotting galactosylated laminin using E8-reactive antibodies. Compared with intact laminin and other laminin fragments, E8 possessed the highest GalTase binding activity, using both membrane-bound and solubilized GalTase. More significantly, the neurite-promoting activity of fragment E8 was shown to be dependent upon its interaction with GalTase. Pregalactosylating purified E8 eliminated subsequent GalTase binding and consequently inhibited neurite initiation; parallel studies on laminin fragments E1-4 or E1 failed to affect neurite outgrowth. Furthermore, anti-GalTase IgG inhibited neurite initiation on purified E8 substrates; control IgG had no effect. These results localize the predominant GalTase binding domain in laminin to fragment E8 and demonstrate that the neurite-promoting activity of E8 is dependent upon its interaction with GalTase.