Darlak K, Franklin G, Woost P, Sonnenfeld E, Twardzik D, Spatola A, Schultz G
Department of Biochemistry, University Louisville, Kentucky 40292.
J Cell Biochem. 1988 Apr;36(4):341-52. doi: 10.1002/jcb.240360404.
Transforming growth factor-alpha (TGF-alpha) is a single chain polypeptide hormone of 50 amino acids that stimulates growth of some human cancer cells via an autocrine mechanism. The domain(s) of TGF-alpha that bind and activate its receptor have not been reported. Hydrophilicity plots of TGF-alpha indicate three discrete sequences that are theoretically exposed on the hormone's surface and thus potentially able to interact with the TGF-alpha receptor. Fragments of TGF-alpha encompassing these hydrophilic domains were prepared by using solid-phase peptide synthesis (SPPS) techniques and purified by use of high performance liquid chromotography (HPLC). Assessment of biological activity of the TGF-alpha fragments indicated that none of the fragments significantly inhibited binding of EGF to the receptor, stimulated DNA synthesis of cells, inhibited EGF-induced DNA synthesis of cells, stimulated growth of cells in soft agar, or induced phosphorylation of the receptor or p35 protein. These results indicate that the receptor binding domain of TGF-alpha is not totally encompassed by any of the separate fragments tested and probably is formed by multiple separate regions of TGF-alpha.
转化生长因子-α（TGF-α）是一种由50个氨基酸组成的单链多肽激素，它通过自分泌机制刺激某些人类癌细胞的生长。尚未报道TGF-α中与受体结合并激活受体的结构域。TGF-α的亲水性图谱显示出三个离散序列，理论上这些序列暴露于激素表面，因此有可能与TGF-α受体相互作用。通过使用固相肽合成（SPPS）技术制备包含这些亲水区的TGF-α片段，并使用高效液相色谱（HPLC）进行纯化。对TGF-α片段的生物学活性评估表明，这些片段均未显著抑制表皮生长因子（EGF）与受体的结合、刺激细胞的DNA合成、抑制EGF诱导的细胞DNA合成、刺激细胞在软琼脂中的生长或诱导受体或p35蛋白的磷酸化。这些结果表明，TGF-α的受体结合结构域并不完全包含在所测试的任何单独片段中，可能是由TGF-α的多个不同区域形成的。
