The regulation of AMP-activated protein kinase by H2O2.
The regulation of AMP-activated protein kinase by H2O2.
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DOI：
10.1006/bbrc.2001.5544
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发表时间：
2001-09-14
影响因子：
3.1
通讯作者：
Ha, J
中科院分区：
文献类型：
--
作者：
Choi, SL;Kim, SJ;Ha, J
AMP活化蛋白激酶（AMPK）是一种异源三聚体丝氨酸/苏氨酸激酶，在导致细胞内AMP：ATP比率增加的条件下被活化。然而，AMPK在氧化应激下如何调节是完全未知的。在本研究中，我们考察了氧化剂H2 O2对AMPK的影响。在NIH-3 T3细胞中，AMPK被H_2O_2瞬时激活并呈浓度依赖性。这种激活与AMP：ATP比率增加、AMPK α 1催化亚基的电泳迁移率变化以及AMPK α 1苏氨酸172磷酸化水平增加（其是上游AMPK激酶的主要体外磷酸化位点）密切相关。所有这些事件都被0.5%二甲基亚砜（一种有效的羟基自由基清除剂）的预处理显著阻断，表明AMPK级联对氧化应激高度敏感。有趣的是，一个特定的酪氨酸激酶抑制剂，genistein，进一步刺激H2 O2诱导的AMPK活性的70%，而不改变AMP：ATP。综上所述，我们的研究结果表明，AMP：ATP比是氧化应激下AMPK响应的主要参数，但AMPK可能部分由酪氨酸激酶依赖性途径调节，这是独立于细胞腺苷核苷酸水平。(C)北京：科学出版社.
AMP-activated protein kinase (AMPK), a heterotrimeric serine/threonine kinase, is activated by conditions leading to an increase of the intracellular AMP: ATP ratio. However, how AMPK is regulated under the oxidative stress is completely unknown. In the present study, we examined effects of the oxidative agent H2O2 on AMPK. AMPK was transiently and concentration-dependently activated by H2O2 in NIH-3T3 cells. This activation was tightly associated with an increased AMP:ATP ratio, an electrophoretic mobility shift of AMPK al catalytic subunit, and an increased phosphorylation level of AMPK alpha1 threonine 172, which is a major in vitro phosphorylation site by the upstream AMPK kinase. All of these events were significantly blocked by the pretreatment of 0.5% dimethyl sulfoxide, a potent hydroxyl radical scavenger, indicating that AMPK cascades are highly sensitive to the oxidative stress. Interestingly, a specific tyrosine kinase inhibitor, genistein, further stimulated the H2O2-induced AMPK activity by 70% without altering the AMP:ATP. Taken together, our results suggest that AMP:ATP ratio is the major parameter to which AMPK responds under the oxidative stress, but AMPK may be regulated in part by a tyrosine kinase-dependent pathway, which is independent of the cellular adenosine nucleotides level. (C) 2001 Academic Press.