Department of Biochemistry, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Email:
Hepatol Res. 2010 Jun;40(6):633-40. doi: 10.1111/j.1872-034X.2010.00645.x.
Hepatitis B virus (HBV) infection is highly correlated with hepatocellular carcinoma. Previous studies have reported that expression of hepatitis B virus pre-S2 mutant surface antigen is related to hepatoma development. An aberrant carbohydrate metabolism is a hallmark of malignant transformation.
We performed yeast two-hybrid screening with HBV pre-S2-del large surface protein (pre-S2Delta) by using human liver cDNA library, and identified the acid alpha-glucosidase (acid alpha-glucosidase) as the novel cellular interacting protein of pre-S2Delta. The association of pre-S2Delta with the acid alpha-glucosidase was confirmed by confocal immunofluorescence and co-immunoprecipitation assay. Further, the acid alpha-glucosidase activity and glycogen content were analyzed in ML-1 cells expressing pre-S2Delta.
The interaction between HBV large surface protein and acid alpha-glucosidase was demonstrated with co-immunoprecipitation in vitro and in vivo, and the binding was mediated through c-terminal region 889-952 amino acid of acid alpha-glucosidase. On the other hand, HBV large surface protein interacted with acid alpha-glucosidase through N-terminal region 1-157 amino acid of HBV large surface protein. Expression of HBV large surface protein enhanced acid alpha-glucosidase activity and resulted in decrease of cellular glycogen.
Our result demonstrates that HBV large surface protein interacts with acid alpha-glucosidase which plays an important role in glycogen balance. Together, these data suggest a novel pathway by which HBV large surface protein affects carbohydrate metabolism.
乙型肝炎病毒（HBV）感染与肝细胞癌高度相关。先前的研究报告称，乙型肝炎病毒前 S2 突变表面抗原的表达与肝癌的发展有关。异常的碳水化合物代谢是恶性转化的标志。
我们通过使用人肝 cDNA 文库，进行了乙型肝炎病毒前 S2 缺失大表面蛋白（pre-S2Delta）的酵母双杂交筛选，鉴定出酸性α-葡萄糖苷酶（acid alpha-glucosidase）是 pre-S2Delta 的新型细胞相互作用蛋白。通过共聚焦免疫荧光和共免疫沉淀实验证实了 pre-S2Delta 与酸性α-葡萄糖苷酶的关联。进一步分析了表达 pre-S2Delta 的 ML-1 细胞中的酸性α-葡萄糖苷酶活性和糖原含量。
体外和体内的共免疫沉淀实验证明了乙型肝炎病毒大表面蛋白与酸性α-葡萄糖苷酶之间的相互作用，并且这种结合是通过酸性α-葡萄糖苷酶的 C 端 889-952 个氨基酸介导的。另一方面，乙型肝炎病毒大表面蛋白通过乙型肝炎病毒大表面蛋白的 N 端 1-157 个氨基酸与酸性α-葡萄糖苷酶相互作用。乙型肝炎病毒大表面蛋白的表达增强了酸性α-葡萄糖苷酶的活性，并导致细胞糖原减少。
我们的结果表明，乙型肝炎病毒大表面蛋白与酸性α-葡萄糖苷酶相互作用，后者在糖原平衡中起着重要作用。总之，这些数据表明了乙型肝炎病毒大表面蛋白影响碳水化合物代谢的新途径。
