Interaction of the NG2 chondroitin sulfate proteoglycan with type VI collagen.
Interaction of the NG2 chondroitin sulfate proteoglycan with type VI collagen.
复制标题
DOI：
10.1083/jcb.111.6.3177
复制
发表时间：
1990-12
影响因子：
7.8
通讯作者：
Healy, P
中科院分区：
文献类型：
--
作者：
Stallcup, W B;Dahlin, K;Healy, P
NG2硫酸软骨素蛋白多糖是一种约500kD的膜相关分子，其核心糖蛋白为300kD。完整的蛋白多糖和少量的300-kD核心蛋白均可与纯化的NG2的多克隆和单克隆抗体免疫共沉淀。在某些细胞系中，抗体共沉淀NG2和VI型胶原，后者在还原条件下以140和250kD的组份出现在SDS-PAGE上。VI型胶原的免疫沉淀似乎不是由于抗体对胶原的识别，而是由于胶原与NG2的结合。对NG2-VI型胶原复合体的研究表明，这两个分子之间的结合是通过蛋白质-蛋白质相互作用而不是涉及糖胺多聚糖的离子相互作用来调节的。胚胎大鼠冰冻切片免疫荧光双标结果显示，NG2和VI型胶原共存于椎间盘和脊柱动脉等结构中。在体外，这两个分子高度共存于几个细胞系的表面。处理这些细胞会导致NG2在细胞表面的分布发生变化，也会导致VI型胶原分布的平行变化。我们的结果提示，细胞表面NG2可能通过与VI型胶原结合来介导细胞与细胞外基质的相互作用。
The NG2 chondroitin sulfate proteoglycan is a membrane-associated molecule of approximately 500 kD with a core glycoprotein of 300 kD. Both the complete proteoglycan and a smaller quantity of the 300-kD core are immunoprecipitable with polyclonal and monoclonal antibodies against purified NG2. From some cell lines, the antibodies coprecipitate NG2 and type VI collagen, the latter appearing on SDS- PAGE as components of 140 and 250 kD under reducing conditions. The immunoprecipitation of type VI collagen does not seem to be due to recognition of the collagen by the antibodies, but rather to binding of the collagen to NG2. Studies on the NG2-type VI collagen complex suggest that binding between the two molecules is mediated by protein- protein interactions rather than by ionic interactions involving the glycosaminoglycans. Immunofluorescence double labeling in frozen sections of embryonic rat shows that NG2 and type VI collagen are colocalized in structures such as the intervertebral discs and arteries of the spinal column. In vitro the two molecules are highly colocalized on the surface of several cell lines. Treatment of these cells resulting in a change in the distribution of NG2 on the cell surface also causes a parallel change in type VI collagen distribution. Our results suggest that cell surface NG2 may mediate cellular interactions with the extracellular matrix by binding to type VI collagen.