Mitogenic and receptor activities of human growth hormone 108-129.
Mitogenic and receptor activities of human growth hormone 108-129.
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DOI：
10.1074/jbc.270.44.26721
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发表时间：
1995-10
期刊：
影响因子：
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通讯作者：
D. Jeoung;D. Allen;S. Guller;V. Yen;M. Sonenberg
中科院分区：
文献类型：
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作者：
D. Jeoung;D. Allen;S. Guller;V. Yen;M. Sonenberg
我们已经选择性地合成了一些肽，包括生长激素（GH）的螺旋3的区域。在3 T3-F442 A前脂肪细胞中评价了这些肽和天然人（h）GH的促有丝分裂和受体活性。在该系统中，野生型hGH是抗促有丝分裂的。相比之下，hGH 108-129刺激DNA合成，而其他GH衍生肽无效。hGH（L）108-129的EC 50约为0.2 nM，在3 T3-F442 A细胞中刺激[3 H]胸苷掺入的最大有效浓度约为0.5 nM。hGH（L）108-129的促有丝分裂活性与胰岛素样生长因子-I相同，但比胰岛素更高。它的效果不如转化生长因子β。通过细胞周期分析，hGH（L）108-129使S/G2/M期细胞比例增加至28%。hGH与hGH（L）108-129共孵育时，可阻断肽的促有丝分裂反应。GH受体的单克隆抗体显著降低125 I-hGH与其受体的结合，但对125 I-hGH（L）108-129的结合无影响。125 I-hGH（L）108-129未重复125 I-hGH与其受体的亲和交联。没有其他GH肽或胰岛素竞争125 I-hGH 108-129的结合。Scatchard分析表明，hGH（L）108-129的Kd为5.2 nM，结合位点/细胞为5.6 x 10（5）。这些研究表明，hGH（L）108-129（一种包含hGH螺旋3的序列）通过与GH受体以外的位点结合发挥作用，并引起高促有丝分裂反应。
We have selectively synthesized a number of peptides encompassing the region of helix 3 of growth hormone (GH). These peptides and native human (h) GH have been evaluated for mitogenic and receptor activities in 3T3-F442A preadipocytes. In this system, wild type hGH is anti-mitogenic. In contrast, hGH 108-129 stimulated DNA synthesis while other GH-derived peptides were ineffective. hGH (L) 108-129 had an EC50 of about 0.2 nM and was maximally effective at about 0.5 nM in stimulating [3H]thymidine incorporation in 3T3-F442A cells. hGH (L) 108-129 was mitogenically as active as insulin-like growth factor-I and more active than insulin. It was less effective than transforming growth factor-beta. By cell cycle analysis, hGH (L) 108-129 increased the proportion of cells in S/G2/M phases to 28%. hGH, when coincubated with hGH (L) 108-129, blocked the mitogenic response of the peptide. A monoclonal antibody to the GH receptor significantly reduced binding of 125I-hGH to its receptor but had no effect on binding of 125I-hGH (L) 108-129. Affinity cross-linking of 125I-hGH to its receptor was not duplicated with 125I-hGH (L) 108-129. No other GH peptides or insulin competed for binding of 125I-hGH 108-129. Scatchard analysis indicated a Kd of 5.2 nM with 5.6 x 10(5) binding sites/cell for hGH (L) 108-129. These studies indicate that hGH (L) 108-129, a sequence encompassing helix 3 of hGH, acts by binding to a site other than the GH receptor and evokes high mitogenic responses.