The adapter protein GRB10 is an endogenous negative regulator of insulin-like growth factor signaling
The adapter protein GRB10 is an endogenous negative regulator of insulin-like growth factor signaling
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DOI：
10.1210/en.2005-0150
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发表时间：
2005-10-01
期刊：
影响因子：
4.8
通讯作者：
Smith, RJ
中科院分区：
文献类型：
--
作者：
Dufresne, AM;Smith, RJ
生长因子IGF-I对人体正常的生长发育至关重要。生长因子受体结合蛋白(GRB)10是一种与IGF-I受体相互作用的蛋白质，因此可能调节IGF-I刺激的生长。然而，内源性Grb10在调节IGF-I活动中的作用尚不清楚。本研究的目的是确定内源性Grb10在IGF信号反应中的作用。利用小干扰RNA，我们证明了Grb10的敲除增强了IGF-I介导的胰岛素受体底物蛋白、Akt/蛋白激酶B和ERK1/2的磷酸化，并导致相应的DNA合成增加。虽然IGF-I受体自动磷酸化通常与受体信号相关，但我们发现在Grb10基因敲除细胞中IGF-I刺激的受体磷酸化减少。蛋白酪氨酸磷酸酶抑制剂过钒酸盐可部分逆转Grb10基因敲除对受体磷酸化的影响，表明内源性Grb10可能阻断磷酸酶对激活的IGF-I受体的作用。标记的小干扰RNA敲除Grb10不会导致相关蛋白Grb7或Grb14的表达增加或减少。作为Grb10功能特异性的进一步证据，最近发现的Grb10与GYF相互作用的蛋白通过酵母双杂交试验被证明与Grb10而不是Grb7或Grb14特异地相互作用。我们得出结论，Grb10是IGF-I刺激的细胞信号和DNA合成的内源性特异性抑制因子。Grb10-IGF-I受体途径的调节可能代表了一种调节IGF-I反应的细胞和组织生长的机制。
The growth factor IGF-I is critical for normal human somatic growth and development. Growth factor receptor-bound protein (Grb) 10 is a protein that interacts with the IGF-I receptor and may thus regulate IGF-I-stimulated growth. However, the role of endogenous Grb10 in regulating IGF-I action is not known. The objective of this study was to determine the function of endogenous Grb10 in IGF signaling responses. Using small interfering RNA, we demonstrate that knockdown of Grb10 enhances IGF-I-mediated phosphorylation of insulin receptor substrate proteins, Akt/protein kinase B, and ERK1/2 and leads to a corresponding increase in DNA synthesis. Although IGF-I receptor autophosphorylation normally correlates with receptor signaling, we demonstrate a decrease in IGF-I-stimulated receptor phosphorylation in Grb10 knockdown cells. Pretreatment of cells with the protein-tyrosine phosphatase inhibitor pervanadate partially reverses this effect of Grb10 knockdown on receptor phosphorylation, indicating that endogenous Grb10 may block phosphatase access to the activated IGF-I receptor. Marked small interfering RNA knockdown of Grb10 does not result in increased or decreased expression of the related proteins Grb7 or Grb14. As further evidence for Grb10 functional specificity, the recently identified Grb10 interacting GYF proteins are shown to interact specifically with Grb10 and not with Grb7 or Grb14, using yeast two-hybrid assays. We conclude that Grb10 functions as a specific endogenous suppressor of IGF-I-stimulated cell signaling and DNA synthesis. Modulation of the Grb10-IGF-I receptor pathway may represent a mechanism that regulates IGF-I-responsive cell and tissue growth.