A central segment of the NG2 proteoglycan is critical for the ability of glioma cells to bind and migrate toward type VI collagen
A central segment of the NG2 proteoglycan is critical for the ability of glioma cells to bind and migrate toward type VI collagen
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DOI：
10.1006/excr.1997.3674
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发表时间：
1997-08-25
影响因子：
3.7
通讯作者：
Stallcup, WB
中科院分区：
文献类型：
--
作者：
Burg, MA;Nishiyama, A;Stallcup, WB
先前的研究已证实 NG2 蛋白多糖直接与 VI 型胶原蛋白结合。为了进一步了解这种相互作用的生化和功能意义，我们使用 NG2 cDNA 构建了一系列 NG2 突变体，其关系遍布 260 kDa NG2 核心蛋白的整个长度。将这些突变体cDNA转染至B28神经胶质瘤细胞后，我们测定了突变体NG2分子将VI型胶原锚定在细胞表面上的能力。11个转染子群体中的8个能够锚定VI型。胶原。无法锚定 VI 型胶原的三种 NG2 变体具有聚集在 NG2 胞外域中央三分之一处的缺失。这些缺失识别了负责结合 VI 型胶原的 NG2 的 469 个氨基酸结构域。通过测试 NG2 转染和未转染的神经胶质瘤细胞向 VI 型胶原迁移的相对能力，探索了 NG2-VI 型胶原相互作用的功能后果。表达NG2的细胞比表达NG2的细胞对VI型胶原表现出更强的迁移反应。 NG2 抗体可以特异性抑制这种增强的迁移。此外，表达NG2（其中胶原结合结构域被删除）的神经胶质瘤细胞未能表现出这种增强的迁移，而其中非胶原结合区域被删除的NG2突变体继续表现出对VI型胶原的趋化性增强。这些比较证实了中央胶原结合结构域在介导NG2和VI型胶原之间功能上重要的相互作用中的重要性。 (C) 1997 年学术出版社。
Previous studies have established that the NG2 proteoglycan binds directly to type VI collagen. To further our understanding of the biochemical and functional significance of this interaction we have used NG2 cDNA to construct a series of NG2 mutants with relations spaced throughout, the entire length of the 260-kDa NG2 core protein. Following transfection of these mutant cDNAs into B28 glioma cells, we determined the ability of mutant NG2 molecules to anchor type Vl collagen on the cell surface, Eight of 11 transfectant populations were able to anchor type VI. collagen. The three NG2 variants incapable of anchoring type VI collagen have deletions clustered within the central one-third of the NG2 ectodomain, These deletions identify a 469-amino-acid domain of NG2 responsible for binding of type VI collagen, Functional consequences of the NG2-type VI collagen interaction were explored by testing the relative ability of NG2-transfected and untransfected glioma cells to migrate toward type VI collagen. NG2-expressing cells exhibited a greater migratory response toward type VI collagen than their NG2-negative counterparts. This enhanced migration could be specifically inhibited with NG2 antibodies. Furthermore, glioma cells expressing NG2 in which the collagen-binding domain was deleted failed to exhibit this enhanced migration, whereas NG2 mutants in which non-collagen-binding, regions were deleted continued to exhibit increased chemotaxis toward the type VI collagen, These comparisons confirm the importance of the central collagen-binding domain in mediating functionally important interactions between NG2 and type VI collagen. (C) 1997 Academic Press.