通过Akt介导的NAD激酶酸化直接刺激NADP+合成
Gerta Hoxhaj1, Issam Ben-Sahra2, Sophie E Lockwood1
1Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
概括
增长因子信号通过Akt酸化激活NAD激酶 (NADK),促进代谢必需的NADP+生产. 这种调节增强了减少细胞过程的NADPH可用性.
科学领域:
- 细胞代谢
- 信号传输
- 酶调节
背景情况:
- 尼古丁胺氨基二核酸盐 (NADP+) 对于降解代谢至关重要,主要是通过其降解形式NADPH.
- 增长因子信号通路在细胞代谢调节中起着重要作用.
- NAD 激酶 (NADK) 是负责 NADP+ 合成的关键酶.
研究的目的:
- 研究酸3-激酶 (PI3K) -Akt途径在调节NADP+和NADPH合成中的作用.
- 阐明Akt影响NADK活动的机制.
- 了解 NADP+ 生产是如何通过生长因子信号敏调节的.
主要方法:
- 研究了细胞中NADP+和NADPH水平的生长因子信号效应.
- 通过生物化学测试在体外研究NADK的酸化.
- 分析了NADK异形的活性,包括缺乏调节性氨基终端域的异形.
主要成果:
- 通过PI3K-Akt通路发出生长因子信号,急剧增加NADP+和NADPH的合成.
- 在特定的血清残留物 (Ser44,Ser46,Ser48) 上直接化NADK,增强其酶活性.
- 一种天然存在的NADK异形 (异形3) 缺乏化部位,其构成性活性较高,表明自身抑制.
结论:
- 通过 Akt 介导的 NADK 酸化是刺激 NADP+ 生产的关键机制.
- 这种酸化减轻了NADK的氨基终端的自身抑制功能,增加了其催化效率.
- 这些发现显示生长因子信号与关键代谢辅因子的调节之间存在直接联系.
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