• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Molecular Biology >CARBOXY-TERMINAL RESIDUES OF MOUSE THYMIDINE KINASE ARE ESSENTIAL FOR RAPID DEGRADATION IN QUIESCENT CELLS
【24h】

CARBOXY-TERMINAL RESIDUES OF MOUSE THYMIDINE KINASE ARE ESSENTIAL FOR RAPID DEGRADATION IN QUIESCENT CELLS

机译：小鼠甲状腺素激酶的羧基末端残基对于快速降解静止细胞至关重要

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The expression of murine thymidine kinase (TK) is highly dependent on the growth state of the cell. The enzyme is nearly undetectable in resting (G(0)) cells, but TK protein levels rise dramatically when serum-stimulated cells reach the G1/S boundary To study post-transcriptional regulation of TK expression, Ltk(-) cells were stably transfected with the coding region of the TK cDNA under the control of a constitutive SV40 promoter. While TK mRNA levels were growth independent in this cell line, TK protein expression and enzyme activity were low in resting cells but increased strongly after growth stimulation by serum. Measurements of translation efficiency and protein stability by immunoprecipitation and pulse-chase experiments indicated that a fourfold change in protein synthesis rate and a sevenfold rise in protein stability are responsible for the increase of TK expression. Progressive deletion of three, six, ten and 20 carboxy-terminal residues of the enzyme resulted in a stepwise loss of its growth-dependent regulation. In addition, a truncated protein lacking the last 30 amino acid residues was expressed at a level tenfold higher than the full-length polypeptide. Further analysis showed that removal of the C-terminal 30 residues did not affect the translation rate, but resulted in the drastic increase in protein half-life. These results demonstrate that residues at the carboxy terminus of the murine enzyme are essential for the growth-dependent regulation of TK protein stability. (C) 1996 Academic Press Limited [References: 41]
机译：鼠胸苷激酶（TK）的表达高度依赖于细胞的生长状态。在静止的（G（0））细胞中几乎检测不到该酶，但是当血清刺激的细胞到达G1 / S边界时，TK蛋白水平急剧上升。为了研究TK表达的转录后调控，Ltk（-）细胞被稳定转染在组成性SV40启动子的控制下具有TK cDNA的编码区。虽然TK mRNA水平在该细胞系中不依赖于生长，但是在静止细胞中TK蛋白表达和酶活性较低，但在血清刺激生长后会明显增加。通过免疫沉淀和脉冲追踪实验对翻译效率和蛋白质稳定性的测量表明，蛋白质合成速率的四倍变化和蛋白质稳定性的七倍升高是TK表达增加的原因。该酶的三个，六个，十个和二十个羧基末端残基的逐步缺失导致其生长依赖性调节的逐步丧失。另外，缺少最后30个氨基酸残基的截短的蛋白以比全长多肽高十倍的水平表达。进一步的分析表明，去除C末端的30个残基不会影响翻译速率，但是会导致蛋白质半衰期的急剧增加。这些结果表明，鼠酶羧基末端的残基对于TK蛋白稳定性的生长依赖性调节至关重要。 （C）1996 Academic Press Limited [参考号：41]

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号