Interaction of Janus kinases JAK-1 and JAK-2 with the insulin receptor and the insulin-like growth factor-1 receptor
Interaction of Janus kinases JAK-1 and JAK-2 with the insulin receptor and the insulin-like growth factor-1 receptor
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DOI：
10.1210/en.139.3.884
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发表时间：
1998-03-01
期刊：
影响因子：
4.8
通讯作者：
Van Obberghen, E
中科院分区：
文献类型：
--
作者：
Gual, P;Baron, V;Van Obberghen, E
胰岛素和胰岛素样生长因子-1 （IGF-1）处理过表达胰岛素受体或IGF-1受体的细胞可促进Janus激酶JAK-1和JAK-2的磷酸化和激活，但对TYK-2没有作用。使用胰岛素，我们观察到jak1在2分钟内最大磷酸化（5.2 +/- 0.6倍），jak2在10分钟内最大磷酸化（2.4 +/- 0.6倍）。在与IGF-1孵育的细胞中，我们发现jak2的最大磷酸化在2分钟内（1.9 +/- 0.2倍），jak1的最大磷酸化在5分钟内（4.5 +/- 0.4倍）。胰岛素或igf - 1刺激细胞的jak被激活，正如它们在体外的自磷酸化所显示的那样。此外，它们能够磷酸化体外天然胰岛素受体底物(IRS)-1和IRS-2片段（GST-IRS-2591-786）。比较胰岛素受体体外磷酸化IRS-1和JAK-1的p -32肽图，发现IRS-1与JAK-1发生不同的磷酸化肽，提示两种激酶可能磷酸化不同的位点。最后，观察到受体和JAK-1的共沉淀，发现两个受体的磷酸化是受体与JAK-1结合所必需的。JAK-1的两个结构域参与了受体与JAK-1复合物的形成，即含有JH7和JK6结构域的n端部分和c端激酶结构域（JH1结构域）。综合我们的数据，我们得出结论：1)胰岛素和IGF-1导致完整细胞中JAK-1和JAK-2的磷酸化和激活；2) JAK-1对IRS-I的磷酸化似乎发生在不同于胰岛素受体磷酸化的位点上；3) JAK-1直接与磷酸化的胰岛素和IGF-1受体相互作用；4) JAK-1的JH7-JH6和JH1结构域负责与胰岛素和IGF-1受体相互作用。
Insulin and insulin-like growth factor-1 (IGF-1) treatment of cells overexpressing the insulin receptor or the IGF-1 receptor promotes phosphorylation and activation of Janus kinases JAK-1 and JAK-2 but not of TYK-2. With insulin, we observed maximal phosphorylation of JAK-1 within 2 min (5.2 +/- 0.6-fold) and maximal phosphorylation of JAK-2 within 10 min (2.4 +/- 0.6-fold). In cells incubated with IGF-1, we found maximal phosphorylation of JAK-2 within 2 min (1.9 +/- 0.2-fold) and of JAK-1 within 5 min (4.5 +/- 0.4-fold). The JAKs from insulin-or IGF-l-stimulated cells were activated, as shown by their autophosphorylation in vitro. Moreover, they were able to phosphorylate in vitro native insulin receptor substrate (IRS)-1 and a fragment of IRS-2 (GST-IRS-2591-786). Comparison of P-32-peptide maps of IRS-1 phosphorylated in vitro by the insulin receptor vs. JAK-1 showed the occurrence of different phosphopeptides, suggesting that different sites are likely to be phosphorylated by the two kinases. Finally, coprecipitation of receptors and JAK-1 was seen, and phosphorylation of both receptors was found to be necessary for receptor binding to JAK-1. Two domains of JAK-1 are involved in the formation of the complex between receptor and JAK-1, i.e. the N-terminal portion containing JH7 and JK6 domains, and the C-terminal kinase domain (JH1 domain). Taking our data together, we conclude that: 1) insulin and IGF-1 lead to phosphorylation and activation of JAK-1 and JAK-2 in intact cells; 2) phosphorylation of IRS-I by JAK-1 seems to occur on sites different from those phosphorylated by the insulin receptor; 3) JAK-1 interacts directly with phosphorylated insulin and IGF-1 receptors; and 4) the JH7-JH6 and JH1 domains of JAK-1 are responsible for the interaction with insulin and IGF-1 receptors.