Two novel proteins that are linked to insulin-like growth factor (IGF-I) receptors by the Grb10 adapter and modulate IGF-I signaling
Two novel proteins that are linked to insulin-like growth factor (IGF-I) receptors by the Grb10 adapter and modulate IGF-I signaling
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DOI：
10.1074/jbc.m211572200
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发表时间：
2003-08-22
影响因子：
4.8
通讯作者：
Smith, RJ
中科院分区：
文献类型：
--
作者：
Giovannone, B;Lee, E;Smith, RJ
Grb10是一种结合激活酪氨酸激酶受体的细胞内结构域的蛋白质，包括胰岛素样生长因子（IGF-I）和胰岛素受体。这是通过两个c端Grb10基序（BPS和Src同源结构域）与受体磷酸酪氨酸残基的相互作用发生的。已发表的转染/过表达研究数据支持Grb10的正调控和负调控作用，因此其生理作用尚不清楚。由于Grb10具有适配蛋白的结构，本研究的目的是确定Grb10是否将其他蛋白连接到IGF-I受体，从而调节IGF-I信号传导。通过酵母双杂交筛选，Grb10的N端与两个新蛋白相互作用，分别命名为GIGYF1 ((G) under bar, rb10 （i) under bar相互作用（GYF） under bar蛋白(1)under bar）和GIGYF2。突变分析表明，在GIGYF1和GIGYF2中有一个17个氨基酸的序列，与前面描述的GYF结构域同源，结合到Grb10 N端串联富含脯氨酸的区域。在表达IGF-I受体的R+成纤维细胞中，在基础状态下可以检测到myc标记的GIGYF1片段与Grb10的结合。IGF-I刺激导致GIGYF1与Grb10的结合增加，以及Grb10和GIGYF1与IGF-I受体的短暂结合，可能是通过Grb10的适配功能。在稍后的时间点，GIGYF1解离，但Grb10仍然与IGF-I受体相连。在R+细胞中，过表达GIGYF1的Grb10结合片段导致igf - i刺激的受体酪氨酸磷酸化显著增加。总之，我们已经确定了一个新蛋白家族的两个成员，它们在IGF-I刺激后通过Grb10适配蛋白与IGF-I受体短暂连接。Grb10和GIGYFs可能协同作用调节受体信号。
Grb10 is a protein that binds to the intracellular domains of activated tyrosine kinase receptors, including insulin-like growth factor (IGF-I) and insulin receptors. This occurs through the interaction of two C-terminal Grb10 motifs (BPS and Src homology domains) with receptor phosphotyrosine residues. Published data from transfection/overexpression studies support both positive and negative regulatory effects of Grb10, thus leaving its physiological role unclear. Because Grb10 has the structure of an adapter protein, the objective of this study was to determine whether Grb10 links other proteins to IGF-I receptors and thus modulates IGF-I signaling. Using yeast two-hybrid screening, the N terminus of Grb10 was shown to interact with two novel proteins, designated GIGYF1 ((G) under bar rb10 (i) under bar nteracting (GYF) under bar protein (1) under bar) and GIGYF2. Mutation analysis indicates that a 17-amino acid sequence in GIGYF1 and GIGYF2, homologous to the GYF domain described previously, binds to tandem proline-rich regions in the N terminus of Grb10. In IGF-I receptor- expressing R+ fibroblasts, there is detectable binding of a Myc-tagged fragment of GIGYF1 to Grb10 in the basal state. Stimulation with IGF-I results in increased binding of GIGYF1 to Grb10 and transient binding of both Grb10 and GIGYF1 to IGF-I receptors, presumably via the adapter function of Grb10. At later time points, GIGYF1 dissociates, but Grb10 remains linked to IGF-I receptors. Overexpression of the Grb10 binding fragment of GIGYF1 in R+ cells results in a significant increase in IGF-I-stimulated receptor tyrosine phosphorylation. In conclusion, we have identified two members of a novel protein family, which become transiently linked to IGF-I receptors by the Grb10 adapter protein following IGF-I stimulation. Grb10 and GIGYFs may act cooperatively to regulate receptor signaling.