在心脏H9c2细胞中，F-box蛋白atrogin-1的稳定性受p38丝裂原活化蛋白激酶途径调控。
Stability of F-box protein atrogin-1 is regulated by p38 mitogen-activated protein kinase pathway in cardiac H9c2 cells.
作者信息
Li Jun-Jie, Zhang Tian-Peng, Meng Yan, Du Jie, Li Hui-Hua
机构信息
Department of Pathology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, No.10 Xitoutiao, You An Men, Beijing, China.
出版信息
Cell Physiol Biochem. 2011;27(5):463-70. doi: 10.1159/000329967. Epub 2011 Jun 15.
BACKGROUND
Atrogin-1/MAFbx is a major atrophy-related E3 ubiquitin ligase that functions as a negative regulator of cardiac hypertrophy. The mRNA expression of atrogin-1 is induced by oxidative stress via p38 mitogen-activated protein kinase (p38 MAPK). However, the molecular mechanisms that regulate the stability of atrogin-1 protein remain unclear.
METHODS
293T and cardiac H9c2 cells were transfected with plasmids as indicated. The in vivo and in vitro ubiquitination assay and pulse-chase analysis were performed to detect the ubiquitination and stability of atrogin-1. The protein levels were measured by Western blot analysis.
RESULTS
We found that atrogin-1 underwent ubiquitin-mediated degradation by proteasome. The F-box motif of atrogin-1 and Skp1-Cul1-Roc1-F-box (SCF) complex are required for ubiquitination and degradation of atrogin-1. Furthermore, p38 MAPK signaling plays critical roles in regulating the ubiquitination and degradation of atrogin-1 as well as serum starvation-induced expression of atrogin-1 and reduction of H9c2 cell size.
CONCLUSION
These findings may define a new mechanism for regulating the stability of atrogin-1 partially by p38 MAPK signaling.
背景
Atrogin-1/MAFbx是一种主要的与萎缩相关的E3泛素连接酶，作为心脏肥大的负调节因子发挥作用。Atrogin-1的mRNA表达由氧化应激通过p38丝裂原活化蛋白激酶（p38 MAPK）诱导。然而，调节Atrogin-1蛋白稳定性的分子机制仍不清楚。
方法
按照指示用质粒转染293T细胞和心脏H9c2细胞。进行体内和体外泛素化测定以及脉冲追踪分析以检测Atrogin-1的泛素化和稳定性。通过蛋白质印迹分析测量蛋白质水平。
结果
我们发现Atrogin-1通过蛋白酶体进行泛素介导的降解。Atrogin-1的F-盒基序和Skp1-Cul1-Roc1-F-盒（SCF）复合物是Atrogin-1泛素化和降解所必需的。此外，p38 MAPK信号传导在调节Atrogin-1的泛素化和降解以及血清饥饿诱导的Atrogin-1表达和H9c2细胞大小减小中起关键作用。
结论
这些发现可能定义了一种部分通过p38 MAPK信号传导调节Atrogin-1稳定性的新机制。
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