Structure and Function of the Core Protein of Fibronectin-binding Proteoglycan

以下是我们在人类胎盘中新发现的一种纤维连接蛋白结合蛋白多糖的研究结果。1.对纤维连接蛋白的蛋白多糖与热裂解蛋白片段相互作用的研究表明，纤维连接蛋白的蛋白多糖通过明胶结合区与纤维连接蛋白结合。2.蛋白多糖不具有促进羊膜细胞在塑料培养皿上黏附和铺展的活性，但如果蛋白多糖已与纤维连接蛋白涂层的培养皿结合，则可促进这些细胞的细胞铺展。这些细胞在纤维连接蛋白涂层的培养皿上表现出良好的粘附性，但如果没有与纤维连接蛋白结合的蛋白水解素，它们就不能很好地扩散。这些数据表明，细胞外基质成分的组合会对细胞活动产生不同的影响。3.对鳞状细胞癌基底膜成分包括蛋白多糖的免疫组织化学研究表明，低分化肿瘤的基底膜往往高度降解，这可能反映出比高分化肿瘤更强的蛋白分解活性。在某些情况下，在肿瘤间质中可以检测到与纤维连接蛋白相关的蛋白多糖，这表明纤维连接蛋白和蛋白多糖之间的结合确实发生在体内。通过对其进行分析，确定其核心蛋白结构，有助于阐明该蛋白的生物学功能。

Followings are new findings from the studies on a fibronectin-binding proteoglycan which we have newly found in the human term placenta. 1. The study of the interaction between the proteoglycan and the thermolysin fragments of fibronectin has indicated that the proteoglycan binds fibronectin via a gelatin-binding domain. 2. The proteoglycan has no activity promoting adhesion and spreading of FL amnion cells on plastic dishes, but it does promote cell-spreading of these cells, if the proteoglycan has been bound to the fibronectin-coated dishes. These cells show good adhesion onto the fibronectin-coated dishes, but they do not spread well without the proteolycan bound to fibronectin. These data suggest that the cell activities can be affected differently by a combination of extracellular matrix components. 3. Immunohistochemical studies on basement membrane components including the proteoglycan of squamous cell carcinoma have suggested that poorly differentiated tumors tend to have highly degraded basement membranes which may reflect a greater proteolytic activity than that in the well differentiated tumors. In some cases, the proteoglycan is detectable in the tumor stroma in association with fibronectin, suggesting that the binding between fibronectin and the proteoglycan does occur in vivo. The determination of the core protein structure by the analysis of cDNA would be useful to elucidate the biological function of this proteoglycan.