Department of Pharmacology, University of Colorado Denver, Aurora, Colorado 80045, United States.
J Proteome Res. 2011 Apr 1;10(4):1837-47. doi: 10.1021/pr101101s. Epub 2011 Mar 7.
Alcoholic liver disease (ALD) is a prominent cause of morbidity and mortality in the United States. Alterations in protein folding occur in numerous disease states, including ALD. The endoplasmic reticulum (ER) is the primary site of post-translational modifications (PTM) within the cell. Glycosylation, the most abundant PTM, affects protein stability, structure, localization, and activity. Decreases in hepatic glycosylation machinery have been observed in rodent models of ALD, but specific protein targets have not been identified. Utilizing two-dimensional gel electrophoresis and liquid chromatography-tandem mass spectrometry, glycoproteins were identified in hepatic microsomal fractions from control and ethanol-fed mice. This study reports for the first time a global decrease in ER glycosylation. Additionally, the identification of 30 glycoproteins within this fraction elucidates pathway-specific alterations in ALD impaired glycosylation. Among the identified proteins, triacylglycerol hydrolase (TGH) is positively affected by glycosylation, showing increased activity following the addition of sugar moieties. Impaired TGH activity is associated with increased cellular storage of lipids and provides a potential mechanism for the observed pathologies associated with ALD.
酒精性肝病（ALD）是美国发病率和死亡率的主要原因。在包括 ALD 在内的许多疾病状态中，蛋白质折叠都会发生改变。内质网（ER）是细胞内翻译后修饰（PTM）的主要场所。糖基化是最丰富的 PTM，它影响蛋白质的稳定性、结构、定位和活性。在 ALD 的啮齿动物模型中观察到肝糖基化机制下降，但尚未确定特定的蛋白质靶标。本研究利用二维凝胶电泳和液相色谱-串联质谱，鉴定了来自对照和乙醇喂养小鼠肝微粒体部分的糖蛋白。这是首次报道 ER 糖基化的全面减少。此外，该部分鉴定出 30 种糖蛋白，阐明了 ALD 中糖基化受损的特定途径改变。在鉴定出的蛋白质中，甘油三酯水解酶（TGH）受到糖基化的正向影响，在添加糖基后，其活性增加。TGH 活性受损与细胞内脂质储存增加有关，为观察到的与 ALD 相关的病理提供了一个潜在的机制。
