INDUCTION OF A SUBSTRATE FOR CASEIN KINASE-II DURING LYMPHOCYTE MITOGENESIS
INDUCTION OF A SUBSTRATE FOR CASEIN KINASE-II DURING LYMPHOCYTE MITOGENESIS
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DOI：
10.1016/0167-4889(84)90146-0
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发表时间：
1984-01-01
期刊：
影响因子：
--
通讯作者：
HARRISON, ML
中科院分区：
文献类型：
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作者：
GEAHLEN, RL;HARRISON, ML
由豆豆蛋白A[Con A]激活的小鼠T淋巴细胞制备的颗粒组分含有内源性蛋白激酶，可磷酸化内源性蛋白底物MW 112,000。在未受刺激的T细胞中，112 kDa[千道尔顿]蛋白的磷酸化大大减少或不存在。磷氨基酸分析表明112 kDa蛋白被标记在丝氨酸上。使用纯化蛋白激酶进行的附加回切实验表明，112 kDa蛋白是酪蛋白激酶II的底物。内源性激酶对112kda蛋白的磷酸化被肝素（一种已知的酪蛋白激酶II抑制剂）抑制。内源性激酶和外源性酪蛋白激酶II修饰的位点通过肽定位实验显示相同。在添加酪蛋白激酶II或不添加酪蛋白II的情况下，用Con A刺激后出现磷酸化的112 kDa蛋白的时间过程表明，112 kDa蛋白在活化的T细胞中被诱导。亚细胞定位研究表明112 kDa蛋白是一个核蛋白。银结合和纯化研究表明112 kDa蛋白位于核仁组织区。
Particulate fractions prepared from concanavalin A[Con A]-activated murine T lymphocytes contain an endogenous protein kinase that phosphorylates an endogenous protein substrate of MW 112,000. The phosphorylation of 112 kDa [kilodalton] protein is greatly reduced or absent in unstimulated T cells. Phosphoamino acid analysis indicates that 112 kDa protein is labeled on a serine. Add-back experiments using purified protein kinases indicate that 112 kDa protein serves as a substrate for casein kinase II. Phosphorylation of 112 kDa protein by the endogenous kinase is inhibited by heparin, a known casein kinase II inhibitor. The site or sites modified by the endogenous kinase and exogenous casein kinase II appear identical by peptide-mapping experiments. A time-course of the appearance of phosphorylated 112 kDa protein following stimulation with Con A, measured in the presence or absence of added casein kinase II, suggests that 112 kDa protein is induced in activated T cells. Subcellular localization studies suggest that 112 kDa protein is a nuclear protein. Silver-binding and purification studies suggest that 112 kDa protein is of the nucleolar organizing region.