Department of Biology, The Catholic University of America, Washington, DC, USA.
Alcohol Clin Exp Res. 2010 Feb;34(2):280-91. doi: 10.1111/j.1530-0277.2009.01091.x. Epub 2009 Nov 24.
Although the clinical manifestations of alcoholic liver disease are well described, little is known about the molecular basis for liver injury. Recent studies have indicated that chronic alcohol consumption leads to the lysine-hyperacetylation of several hepatic proteins, and this list is growing quickly.
To identify other hyperacetylated proteins in ethanol-fed livers, we chose a proteomics approach. Cytosolic and membrane proteins (excluding nuclei) were separated on 2D gels, transferred to PVDF and immunoblotted with antibodies specific for acetylated lysine residues. Hyperacetylated proteins were selected for trypsin digestion and mass spectrometric analysis.
In all, 40 proteins were identified, 11 of which are known acetylated proteins. Remarkably, the vast majority of hyperacetylated membrane proteins were mitochondrial residents. Hyperacetylated cytosolic proteins ranged in function from metabolism to cytoskeletal support. Notably, 3 key anti-oxidant proteins were identified whose activities are impaired in ethanol-treated cells. We confirmed that the anti-oxidant enzyme, glutathione peroxidase 1, actin and cortactin are hyperacetylated in ethanol-treated livers.
Alcohol-induced hyperacetylation of multiple proteins may contribute to the development of liver injury. The abundance of acetylated mitochondrial proteins further suggests that this modification is important in regulating liver metabolism and when perturbed, may contribute to the progression of a variety of metabolic diseases.
尽管酒精性肝病的临床表现已有详细描述，但对于肝损伤的分子基础知之甚少。最近的研究表明，慢性酒精摄入会导致几种肝蛋白赖氨酸的超乙酰化，而且这一列表还在迅速增加。
为了鉴定乙醇喂养的肝脏中其他发生超乙酰化的蛋白，我们选择了一种蛋白质组学方法。细胞溶质和膜蛋白（不包括核）在 2D 凝胶上分离，转移到 PVDF 上，并与针对赖氨酸乙酰化残基的特异性抗体进行免疫印迹。选择超乙酰化蛋白进行胰蛋白酶消化和质谱分析。
总共鉴定出 40 种蛋白，其中 11 种是已知的乙酰化蛋白。值得注意的是，绝大多数超乙酰化的膜蛋白都是线粒体居民。超乙酰化的胞质蛋白的功能从代谢到细胞骨架支持不等。值得注意的是，鉴定出 3 种关键的抗氧化蛋白，其活性在乙醇处理的细胞中受损。我们证实，抗氧化酶谷胱甘肽过氧化物酶 1、肌动蛋白和桩蛋白在乙醇处理的肝脏中发生超乙酰化。
多种蛋白的酒精诱导超乙酰化可能导致肝损伤的发生。大量的乙酰化线粒体蛋白进一步表明，这种修饰对于调节肝脏代谢很重要，而当这种修饰受到干扰时，可能会导致多种代谢疾病的进展。
