Insulin-stimulated microtubule-associated protein kinase is phosphorylated on tyrosine and threonine in vivo.
Insulin-stimulated microtubule-associated protein kinase is phosphorylated on tyrosine and threonine in vivo.
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胰岛素刺激的微管相关蛋白激酶在体内的酪氨酸和苏氨酸上被磷酸化。
DOI：
10.1073/pnas.85.11.3753
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发表时间：
1988
影响因子：
11.1
通讯作者：
Sturgill,TW
中科院分区：
文献类型：
--
作者：
Ray,LB;Sturgill,TW
3 T3-L1细胞暴露于胰岛素刺激可溶性丝氨酸（苏氨酸）特异性蛋白激酶，其在体外磷酸化微管相关蛋白2（MAP-2）。这种酶，称为MAP激酶，是从胰岛素处理或对照细胞中分离出来的，用32 Pi放射性标记。一个40-kDa的磷蛋白被发现与酶的活性在疏水相互作用和凝胶过滤色谱从细胞中提取物与胰岛素刺激的确切对应。MAP激酶活性和磷蛋白都不存在从未经处理的细胞制备的馏分。掺入40-kDa蛋白的32 P在用碱处理期间是稳定的。磷酸氨基酸分析证实，放射性标记主要掺入磷酸酪氨酸和磷酸苏氨酸在较小程度上。此外，MAP激酶被磷酸酪氨酸抗体不完全但特异性地吸附。我们的结论是，根据这些数据和本实验室的其他研究，MAP激酶在体内酪氨酸磷酸化。这些数据与MAP激酶可能是胰岛素受体或另一种胰岛素调节酪氨酸激酶的底物的可能性一致。
Exposure of 3T3-L1 cells to insulin stimulates a soluble, serine(threonine)-specific protein kinase that phosphorylates microtubule-associated protein 2 (MAP-2) in vitro. The enzyme, termed MAP kinase, was isolated from insulin-treated or control cells radiolabeled with 32Pi. A 40-kDa phosphoprotein was found to elute in exact correspondence with enzymatic activity during hydrophobic interaction and gel filtration chromatography of extracts from cells stimulated with insulin. Both MAP kinase activity and the phosphoprotein were absent in fractions prepared from untreated cells. The 32P incorporated into the 40-kDa protein was stable during treatment with alkali. Phospho amino acid analysis confirmed that the radiolabel was primarily incorporated into phosphotyrosine and to a lesser extent phosphothreonine. In addition, MAP kinase was incompletely but specifically adsorbed by antibodies to phosphotyrosine. We conclude, based on these data and additional studies from this laboratory, that MAP kinase is phosphorylated on tyrosine in vivo. The data are consistent with the possibility that MAP kinase may be a substrate for the insulin receptor or another insulin-regulated tyrosine kinase.