MULTIPLE CDNAS ENCODING THE ESK KINASE PREDICT TRANSMEMBRANE AND INTRACELLULAR ENZYME ISOFORMS
MULTIPLE CDNAS ENCODING THE ESK KINASE PREDICT TRANSMEMBRANE AND INTRACELLULAR ENZYME ISOFORMS
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DOI：
10.1128/mcb.12.6.2681
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发表时间：
1992-06-01
影响因子：
5.3
通讯作者：
BELL, JC
中科院分区：
文献类型：
--
作者：
DOUVILLE, EMJ;AFAR, DEH;BELL, JC
一种新的蛋白激酶，埃斯克激酶，已被分离的胚胎癌（EC）细胞系，通过使用表达克隆策略。 两个独立的cDNA克隆（2.97和2.85 kb）的序列分析表明EC细胞中存在两种埃斯克亚型。 埃斯克-1的cDNA序列预测了一个857个氨基酸的蛋白激酶，具有一个假定的跨膜结构域，而埃斯克-2的cDNA预测了一个831个氨基酸的激酶，缺乏这个结构域。 在成年小鼠细胞中，埃斯克mRNA水平在具有高增殖率或相当大的干细胞区室的组织中最高，这表明埃斯克激酶可能在控制细胞增殖或分化中发挥一定作用。 正如从筛选程序中所预期的，埃斯克激酶的细菌表达在免疫印迹上与抗磷酸酪氨酸抗体反应。 此外，在体外激酶测定中，显示埃斯克激酶在丝氨酸、苏氨酸和酪氨酸残基上磷酸化自身和外源底物髓鞘碱性蛋白，证实了埃斯克激酶是丝氨酸/苏氨酸/酪氨酸蛋白激酶家族的新成员。
A novel protein kinase, the Esk kinase, has been isolated from an embryonal carcinoma (EC) cell line by using an expression cloning strategy. Sequence analysis of two independent cDNA clones (2.97 and 2.85 kb) suggested the presence of two Esk isoforms in EC cells. The esk-1 cDNA sequence predicted an 857-amino-acid protein kinase with a putative membrane-spanning domain, while the esk-2 cDNA predicted an 831-amino-acid kinase which lacked this domain. In adult mouse cells, esk mRNA levels were highest in tissues possessing a high proliferation rate or a sizeable stem cell compartment, suggesting that the Esk kinase may play some role in the control of cell proliferation or differentiation. As anticipated from the screening procedure, bacterial expression of the Esk kinase reacted with antiphosphotyrosine antibodies on immunoblots. Furthermore, in in vitro kinase assays, the Esk kinase was shown to phosphorylate both itself and the exogenous substrate myelin basic protein on serine, threonine, and tyrosine residues, confirming that the Esk kinase is a novel member of the serine/threonine/tyrosine family of protein kinases.