Characterization of a peptide inhibitor of janus kinase 2 that mimics suppressor of cytokine signaling 1 function
Characterization of a peptide inhibitor of janus kinase 2 that mimics suppressor of cytokine signaling 1 function
复制标题
DOI：
10.4049/jimmunol.172.12.7510
复制
发表时间：
2004-06-15
影响因子：
4.4
通讯作者：
Subramaniam, PS
中科院分区：
文献类型：
--
作者：
Flowers, LO;Johnson, HM;Subramaniam, PS
细胞因子如ifn - γ的正调控和负调控是正常体内平衡功能的关键。细胞中ifn - γ的负调控是通过称为细胞因子信号抑制因子（SOCS） 1和-3的蛋白质发生的。SOCS-1通过结合酪氨酸激酶Janus激酶（JAK）2的自磷酸化位点抑制ifn - γ功能。我们开发了一种短的12聚肽WLVFFVIFYFFR，它与JAK2的自磷酸化位点结合，导致其自磷酸化抑制以及ifn - γ受体亚基IFNGR-1的磷酸化。JAK2酪氨酸激酶抑制剂肽（Tkip）不结合或抑制血管内皮生长因子受体的酪氨酸自磷酸化或原癌基因酪氨酸激酶c-src的底物肽磷酸化。Tkip还能抑制表皮生长因子受体的自磷酸化，这与表皮生长因子受体受SOCS-1和SOCS-1调控的事实一致。soc -3，类似于JAK2。虽然Tkip与未磷酸化的JAK2自磷酸化位点肽结合，但与酪氨酸-1007磷酸化的JAK2自磷酸化位点肽结合明显更好。SOCS-1只识别磷酸化状态的JAK2位点。因此，Tkip识别JAK2自磷酸化位点类似于SOCS-1，但不是完全相同的方式。与JAK2的抑制一致，Tkip抑制ifn - γ诱导抗病毒状态的能力，并在类似于10mum的浓度下上调细胞上MHC I类分子。这与促红细胞生成素受体的SOCS-3的K-d相似。这些数据代表了SOCS-1模拟肽调节JAK2酪氨酸激酶功能的概念验证。
Positive and negative regulation of cytokines such as IFN-gamma are key to normal homeostatic function. Negative regulation of IFN-gamma in cells occurs via proteins called suppressors of cytokine signaling (SOCS)l and -3. SOCS-1 inhibits IFN-gamma function by binding to the autophosphorylation site of the tyrosine kinase Janus kinase (JAK)2. We have developed a short 12-mer peptide, WLVFFVIFYFFR, that binds to the autophosphorylation site of JAK2, resulting in inhibition of its autophosphorylation as well as its phosphorylation of IFN-gamma receptor subunit IFNGR-1. The JAK2 tyrosine kinase inhibitor peptide (Tkip) did not bind to or inhibit tyrosine autophosphorylation of vascular endothelial growth factor receptor or phosphorylation of a substrate peptide by the protooncogene tyrosine kinase c-src. Tkip also inhibited epidermal growth factor receptor autophosphorylation, consistent with the fact that epidermal growth factor receptor is regulated by SOCS-1 and. SOCS-3, similar to JAK2. Although Tkip binds to unphosphorylated JAK2 autophosphorylation site peptide, it binds significantly better to tyrosine-1007 phosphorylated JAK2 autophosphorylation site peptide. SOCS-1 only recognizes the JAK2 site in its phosphorylated state. Thus, Tkip recognizes the JAK2 autophosphorylation site similar to SOCS-1, but not precisely the same way. Consistent with inhibition of JAK2, Tkip inhibited the ability of IFN-gamma to induce an antiviral state as well as up-regulate MHC class I molecules on cells at a concentration of similar to10 muM. This is similar to the K-d of SOCS-3 for the erythropoietin receptor. These data represent a proof-of-concept demonstration of a peptide mimetic of SOCS-1 that regulates JAK2 tyrosine kinase function.