Hepatitis B virus X protein induces perinuclear mitochondrial clustering in microtubule- and dynein-dependent manners
Hepatitis B virus X protein induces perinuclear mitochondrial clustering in microtubule- and dynein-dependent manners
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DOI：
10.1128/jvi.01863-06
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发表时间：
2007-02-01
影响因子：
5.4
通讯作者：
Cho, Hyeseong
中科院分区：
文献类型：
--
作者：
Kim, Sujeong;Kim, Hye-Young;Cho, Hyeseong
B型肝炎病毒（HBV）X蛋白（HBx）被认为在HBV复制和肝癌的发展中起关键作用。很明显，HBx诱导线粒体聚集在核周围，但线粒体聚集的分子基础尚不清楚。由于线粒体作为马达蛋白的货物沿细胞骨架沿着移动，我们假设由HBx诱导的线粒体聚集是通过改变细胞内运动而发生的。在这里，我们证明了用微管破坏药物（诺考达唑）处理HBx表达细胞废除了线粒体聚集，而去除诺考达唑在30至60分钟内恢复了聚集，表明线粒体转运以微管依赖性方式发生。然而，加入细胞松弛素D-破坏肌动蛋白丝，并没有明显影响线粒体聚类。通过观察HBV相关肝癌细胞和HBV复制细胞进一步研究线粒体聚集。重要的是，通过显微注射中和性抗动力蛋白中间链抗体、动力蛋白过表达或加入动力蛋白ATP酶抑制剂来消除HBx表达细胞中的动力蛋白活性，可显著抑制线粒体聚集。此外，SB 203580减弱了HBx诱导的线粒体聚集，HBx诱导了p38有丝分裂原活化蛋白激酶（MAPK）的激活并抑制了p38激酶活性。总之，HBx激活p38 MAPK有助于微管依赖性动力蛋白活性的增加。这些数据表明，HBx在亚细胞转运系统中起着新的调节作用，可能促进HBV复制过程中子代颗粒的成熟和/或组装。此外，HBx诱导的粘附子聚集可能代表慢性病毒感染期间疾病进展的细胞过程。
The hepatitis B virus (HBV) X protein (HBx) is thought to play a key role in HBV replication and the development of liver cancer. It became apparent that HBx induces mitochondrial clustering at the nuclear periphery, but the molecular basis for mitochondrial clustering is not understood. Since mitochondria move along the cytoskeleton as a cargo of motor proteins, we hypothesized that mitochondrial clustering induced by HBx occurs by an altered intracellular motility. Here, we demonstrated that the treatment of HBx-expressing cells with a microtubule-disrupting drug (nocodazole) abrogated mitochondrial clustering, while the removal of nocodazole restored clustering within 30 to 60 min, indicating that mitochondrial transport is occurring in a microtubule-dependent manner. The addition of a cytochalasin D-disrupting actin filament, however, did not measurably affect mitochondrial clustering. Mitochondrial clustering was further studied by observations of HBV-related hepatoma cells and HBV-replicating cells. Importantly, the abrogation of the dynein activity in HBx-expressing cells by microinjection of a neutralizing anti-dynein intermediate-chain antibody, dynamitin overexpression, or the addition of a dynein ATPase inhibitor significantly suppressed the mitochondrial clustering. In addition, HBx induced the activation of the p38 mitogen-activated protein kinase (MAPK) and inhibition of the p38 kinase activity by SB203580-attenuated HBx-induced mitochondrial clustering. Taken together, HBx activation of the p38 MAPK contributed to the increase in the microtubule-dependent dynein activity. The data suggest that HBx plays a novel regulatory role in subcellular transport systems, perhaps facilitating the process of maturation and/or assembly of progeny particles during HBV replication. Furthermore, mitochondrion aggregation induced by HBx may represent a cellular process that underlies disease progression during chronic viral infection.