Cloning and expression of a novel MAPKK-like protein kinase, lymphokine-activated killer T-cell-originated protein kinase, specifically expressed in the testis and activated lymphoid cells
Cloning and expression of a novel MAPKK-like protein kinase, lymphokine-activated killer T-cell-originated protein kinase, specifically expressed in the testis and activated lymphoid cells
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DOI：
10.1074/jbc.m909629199
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发表时间：
2000-07-14
影响因子：
4.8
通讯作者：
Ueda, N
中科院分区：
文献类型：
--
作者：
Abe, Y;Matsumoto, S;Ueda, N
从淋巴因子激活的杀伤T（T-LAK）细胞消减cDNA文库中分离到一种新的蛋白激酶TOPK（T-LAK cell-originated protein kinase）。TOPK基因的开放阅读框编码322个氨基酸的蛋白质，具有蛋白激酶结构域特征。对TOPK mRNA的5 '端的帽位点分析揭示了两种形式，一种主要的全长形式和一种在5'端的次要剪接形式，两者编码相同的蛋白质。BLAST同源性搜索和系统发育分析表明，TOPK与双特异性丝裂原活化蛋白激酶激酶（MAPKK）有关。TOPK基因转染COS-7细胞后，p38 MAPK磷酸化水平上调，而ERK 1/2和SAPK/JNK磷酸化水平无明显变化。凝胶沉淀实验表明TOPK蛋白在体外可与p38蛋白结合。TOPK mRNA表达的组织分布在睾丸、T-LAK细胞、活化的淋巴样细胞和淋巴样肿瘤中具有特异性。另一方面，失活的T-LAK细胞不显示TOPK mRNA表达。这些数据表明，TOPK是一种新的MEK 3/6相关MAPKK的新成员，可能参与淋巴样细胞的活化并支持睾丸功能。
A novel protein kinase, TOPK (T-LAK cell-originated protein kinase), was isolated from a lymphokine-activated killer T (T-LAK) cell subtraction cDNA fragment library. The open reading frame of the TOPK gene encodes a protein of 322 amino acids, possessing a protein kinase domain profile. The cap site analysis of the 5'-end of TOPK mRNA revealed two forms, a major full-length form and a minor spliced form at the 5'-site, both encoding the same protein. A BLAST homology search and phylogenetic analysis indicated that TOPK is related to dual specific mitogen-activated protein kinase kinase (MAPKK). The transfection of the TOPK gene to COS-7 cells up-regulated a phosphorylation of p38 MAPK but not ERK1/2 or SAPK/JNK. Gel precipitation study indicated that TOPK protein can be associated with p38 in vitro. Tissue distribution of TOPK mRNA expression was specific for the testis, T-LAK cells, activated lymphoid cells, and lymphoid tumors. On the other hand, deactivated T-LAK, cells did not show TOPK mRNA expression. These data suggest that TOPK is a newly identified member of a novel MEK3/6-related MAPKK that may be enrolled in the activation of lymphoid cells and support testicular functions.