Identification of a receptor binding region on the beta subunit of human follicle-stimulating hormone.
Identification of a receptor binding region on the beta subunit of human follicle-stimulating hormone.
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人卵泡刺激素β亚基上受体结合区域的鉴定。
DOI：
10.1021/bi00402a026
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发表时间：
1988
期刊：
影响因子：
2.9
通讯作者：
ReichertJr,LE
中科院分区：
文献类型：
--
作者：
Schneyer,AL;Sluss,PM;Huston,JS;Ridge,RJ;ReichertJr,LE
修订稿于 1987 年 9 月 15 日收到 摘要：小鼠表皮生长因子 (mEGF) 和人卵泡刺激素 (hFSH)(hFSH-/3) 的 ß 亚基已被证明可以在体外抑制完整 hFSH 与其睾丸膜受体的结合。 hFSH-/3 和 mEGF 均含有四肽序列 Thr-Arg-Asp-Leu (TRDL)。先前的结果表明，合成的 TRDL 抑制完整 hFSH 与受体的结合。因此，我们使用 hFSH 多克隆抗血清 [NHPP 抗 hFSH 第 4 批 (AB4)] 研究了 TRDL 位于 FSH-/3 暴露区域的可能性，该多克隆抗血清识别完整 hFSH 及其 ß 亚基上的决定簇，但不识别 a 亚基。来自几种哺乳动物物种的垂体 FSH 制剂在异源 [AB4 和 125 I 标记的绵羊 FSH (125 I-oFSH)] 放射免疫测定中产生平行的抑制曲线，其相对效力与通过放射性配体受体测定测定的相同制剂观察到的相对效力相似。该抗血清还竞争性抑制 125I-FSH 与受体的结合。因此，AB4似乎能够识别高度保守的抗原决定簇，并且位于或靠近涉及FSH受体的激素识别的区域。浓度为 1.36 mg/管 (9 X 3 M) 的合成 TRDL 可抑制 50% 的 125I-hFSH 与抗血清的结合。其他四肽（Thr-Pro-Arg-Lys 和 Lys-Thr-Cys-Thr）在相当浓度下没有抑制活性。游离氨基酸 T、R、D 和 L 的混合物仅在比 TRDL 显着更高的浓度下才抑制放射性配体结合。 TRDL 能够以非细胞毒性水平抑制培养的支持细胞对 oFSH 的体外生物反应，进一步表明 FSH 受体接触区域中 TRDL 的存在。在所有三个测定系统中，TRDL 相对于 FSH 的效力降低表明，它仅代表完整激素及其 ß 亚基的较大决定因素的一部分。这些结果支持涉及多个离散接触点（决定因素）的激素-受体相互作用模型，其中一些影响结合，而另一些可能涉及细胞反应的启动。我们的结果进一步表明 TRDL 是一个 FSH 受体结合区的组成部分..^^。尽管我们对糖蛋白激素受体识别位点的了解仍然不准确，但它们的存在通常是从激素-受体相互作用的结构功能研究中推断出来的（Ward，1978；Pierce＆Parsons，1981）。血清中单个激素的受体识别是通过形成高亲和力激素-受体复合物而发生的。激素与受体的相互作用
Revised Manuscript Received September 15, 1987 abstract: Mouse epidermal growth factor (mEGF) and the ß subunit of human follicle-stimulating hormone (hFSH)(hFSH-/3) have been shown to inhibit binding of intact hFSH to its testes membrane receptor in vitro. Both hFSH-/3and mEGF contain the tetrapeptide sequence Thr-Arg-Asp-Leu (TRDL). Previous results demonstrated that synthetic TRDL inhibited binding of intact hFSH to receptor. We therefore investigated the possibility that TRDL was located on an exposed region of FSH-/3 using a polyclonal antiserum to hFSH [NHPP anti-hFSH batch 4 (AB4)] which recognized determinants on intact hFSH and its ß subunit, but not the a subunit. Pituitary FSH preparations from several mammalian species produced parallel inhibition curves in a heterologous [AB4 and 125I-labeled ovine FSH (125I-oFSH)] ra-dioimmunoassay with relative potencies similar to those observed for the same preparations assayed by radioligand receptor assay. This antiserum also competitively inhibited 125I-FSH binding to receptor. Thus, AB4 appeared to recognize antigenic determinants that are highly conserved and located at or near regions involved with hormone recognition of receptor for FSH. Synthetic TRDL inhibited 50% of 125I-hFSH binding to antiserum at a concentration of 1.36 mg/tube (9 X 3 M). Other tetrapeptides (Thr-Pro-Arg-Lys and Lys-Thr-Cys-Thr) had no inhibitory activity at comparable concentrations. A mixture of the free amino acids T, R, D, and L inhibitedradioligand binding only at significantly higher concentrations than TRDL. The presence of TRDL in a receptor contact region of FSH was further suggested by its ability to inhibit the in vitro biological response to oFSH by cultured Sertoli cells atnoncytotoxic levels. The reduced potency of TRDL relative to FSH in all three assay systems suggests that it represents only a portion of a larger determinant on the intact hormone and its ß subunit. These results support a model of hormone-receptor interaction involving multiple, discrete contact points (determinants), some of which influence binding while others may be involved with initiation of a cellular response. Our results further suggest that TRDL is a constituent of one FSH receptor binding region..^^. lthough our knowledge of receptor recognition sites for glycoprotein hormones is still imprecise, their existence is usually inferred from structure-function studies of hormone-receptor interactions (Ward, 1978; Pierce & Parsons, 1981). Receptor recognition of individual hormones in serum occurs through formation of high-affinity hormone-receptor complexes. The interactions between hormone and receptor