Expression and phosphorylation of TOPK during spermatogenesis
Expression and phosphorylation of TOPK during spermatogenesis
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DOI：
10.1111/j.1440-169x.2005.00834.x
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发表时间：
2005-12-01
影响因子：
2.5
通讯作者：
Kito, K
中科院分区：
文献类型：
--
作者：
Fujibuchi, T;Abe, Y;Kito, K
在正常器官和组织中，MAPKK样有丝分裂蛋白激酶TOPK仅在睾丸中表达。我们分析了TOPK的表达和磷酸化，以探讨该激酶在精子发生中的功能作用。TOPK蛋白主要在精母细胞和精子细胞的胞浆中表达，而在精子细胞和精原细胞中不表达。TOPK-Thr-9是CDK1/Cyclin B的靶残基，在有丝分裂和减数分裂过程中被特异性地磷酸化，而作为ATP口袋的关键氨基酸，TOPK-Thr-198在细胞周期中持续被磷酸化。这些数据表明，具有重要增殖活性的生精生殖细胞表达TOPK。由于TOPK-Thr-9在有丝分裂和减数分裂过程中都被磷酸化，TOPK被认为在细胞质分裂和/或染色体分离中起作用，但在DNA复制中不起作用。
Among normal organs and tissues, the MAPKK-like mitotic protein kinase TOPK is expressed exclusively in the testis. We analyzed the expression and phosphorylation of TOPK to address the functional role of this kinase during spermatogenesis. TOPK protein is expressed mainly in the cytosol of spermatocytes and spermatids, but not in spermatids and spermatogonia in situ. TOPK-Thr-9, a cdk1/cyclin B target residue, was specifically phosphorylated during mitotic and meiotic phases, while TOPK-Thr-198, a key amino acid for the ATP pocket, was constantly phosphorylated irrespective of the cell cycle. These data indicate that spermatogenic germ cells with vital proliferation activity express TOPK. As TOPK-Thr-9 was phosphorylated during both mitosis and meiosis, TOPK was indicted to play a role in cytokinesis and/or chromosomal segregation but not in DNA replication.