Segarini P R, Seyedin S M
Connective Tissue Research Laboratories, Collagen Corporation, Palo Alto, California 94303.
J Biol Chem. 1988 Jun 15;263(17):8366-70.
Proteoglycans are constituents of the cell surface that may play important roles in the regulation of cell behavior. Here we report that the 250-kDa receptor subunit that binds the multifunctional protein, transforming growth factor-beta 1 (TGF-beta 1), contains chains of heparan sulfate and chondroitin sulfate and thus is a proteoglycan. Digestion of TGF-beta 1-receptor complexes with glycosaminoglycan (GAG)-specific degradative enzymes yield core proteins of 115-140 kDa. Cell monolayers that had been predigested with GAG-specific degradative enzymes were capable of binding high levels of TGF-beta 1, but the size of the binding components was shifted from the high molecular weight species to the lower molecular weight core proteins, indicating that GAG chains are not necessary for TGF-beta 1 binding to the cell. The presence of GAG chains on the receptor subunit indicates that it has the potential for interaction with the extracellular matrix.
蛋白聚糖是细胞表面的组成成分，可能在细胞行为的调节中发挥重要作用。在此我们报告，与多功能蛋白转化生长因子-β1（TGF-β1）结合的250 kDa受体亚基含有硫酸乙酰肝素和硫酸软骨素链，因此是一种蛋白聚糖。用糖胺聚糖（GAG）特异性降解酶消化TGF-β1受体复合物可产生115 - 140 kDa的核心蛋白。用GAG特异性降解酶预先消化的细胞单层能够结合高水平的TGF-β1，但结合成分的大小从高分子量物种转变为低分子量核心蛋白，这表明GAG链对于TGF-β1与细胞的结合不是必需的。受体亚基上GAG链的存在表明它具有与细胞外基质相互作用的潜力。
