The nuclear protein Artemis promotes AMPK activation by stabilizing the LKB1-AMPK complex
The nuclear protein Artemis promotes AMPK activation by stabilizing the LKB1-AMPK complex
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DOI：
10.1016/j.bbrc.2012.09.140
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发表时间：
2012-11-02
影响因子：
3.1
通讯作者：
Kobayashi, Masanobu
中科院分区：
文献类型：
--
作者：
Nakagawa, Koji;Uehata, Yasuko;Kobayashi, Masanobu
AMP活化蛋白激酶（AMPK）是由α催化α亚基和调节β和γ亚基组成的异源三聚体Ser/Thr激酶;它作为控制细胞能量稳态的能量传感器起作用。响应于增加的细胞AMP/ATP比率，AMPK通过上游AMPK激酶（AMPKK）（包括肿瘤抑制剂肝激酶B1（LKB 1））在α亚基中的Thr 172处磷酸化而被激活。为了阐明AMPK激活的更精确的分子机制，我们进行了酵母双杂交筛选，并分离了编码核蛋白Artemis/DNA交联修复1C（DCLRE 1C）作为AMPK α 2结合蛋白的互补DNA（cDNA）。发现Artemis与AMPK α 2共免疫沉淀，并且通过U2 OS细胞中的免疫荧光染色证实Artemis与AMPK α 2在细胞核中的共定位。此外，Artemis的过表达增强了AMPK α 2和AMPK底物乙酰辅酶A羧化酶（ACC）的磷酸化。相反，RNAi介导的Artemis敲低降低了AMPK和ACC磷酸化。此外，Artemis显著增加了AMPK α 2和LKB 1之间的物理联系。总之，这些结果表明，Artemis通过稳定LKB 1-AMPK复合物作为AMPK信号传导的正调节剂发挥作用。(C)2012 Elsevier Inc. All rights reserved.
AMP-activated protein kinase (AMPK) is a hetero-trimeric Ser/Thr kinase composed of alpha catalytic a subunit and regulatory beta and gamma subunits; it functions as an energy sensor that controls cellular energy homeostasis. In response to an increased cellular AMP/ATP ratio, AMPK is activated by phosphorylation at Thr172 in the alpha-subunit by upstream AMPK kinases (AMPKKs), including tumor suppressor liver kinase B1 (LKB1). To elucidate more precise molecular mechanisms of AMPK activation, we performed yeast two-hybrid screening and isolated the complementary DNA (cDNA) encoding the nuclear protein Artemis/DNA cross-link repair 1C (DCLRE1C) as an AMPK alpha 2-binding protein. Artemis was found to co-immunoprecipitate with AMPK alpha 2, and the co-localization of Artemis with AMPK alpha 2 in the nucleus was confirmed by immunofluorescence staining in U2OS cells. Moreover, over-expression of Artemis enhanced the phosphorylation of AMPK alpha 2 and the AMPK substrate acetyl-CoA carboxylase (ACC). Conversely, RNAi-mediated knockdown of Artemis reduced AMPK and ACC phosphorylation. In addition, Artemis markedly increased the physical association between AMPK alpha 2 and LKB1. Taken together, these results suggest that Artemis functions as a positive regulator of AMPK signaling by stabilizing the LKB1-AMPK complex. (C) 2012 Elsevier Inc. All rights reserved.