Heat Shock Protein 90 Ensures Efficient Mumps Virus Replication by Assisting with Viral Polymerase Complex Formation
Heat Shock Protein 90 Ensures Efficient Mumps Virus Replication by Assisting with Viral Polymerase Complex Formation
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DOI：
10.1128/jvi.02220-16
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发表时间：
2017-03-01
影响因子：
5.4
通讯作者：
Takeda, Makoto
中科院分区：
文献类型：
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作者：
Katoh, Hiroshi;Kubota, Toru;Takeda, Makoto
副粘病毒RNA由病毒RNA依赖性RNA聚合酶（RdRp）合成，该聚合酶由大（L）蛋白及其辅因子磷蛋白（P蛋白）组成。L蛋白是催化RNA合成、mRNA加帽和mRNA聚腺苷酸化的多功能蛋白。越来越多的证据表明，几种副粘病毒L蛋白的稳定性受热休克蛋白90（Hsp 90）的调节。在这项研究中，我们证明了热休克蛋白90的活性是重要的腮腺炎病毒（MuV）的复制。Hsp 90活性是L蛋白稳定性和活性所必需的，因为Hsp 90特异性抑制剂17-烯丙基氨基-17-去甲氧基格尔德霉素（17-AAG）使MuV L蛋白不稳定并抑制病毒RNA合成。然而，一旦L蛋白与P蛋白形成成熟的聚合酶复合物，L蛋白的稳定性和活性就不再需要Hsp 90活性。当Hsp 90活性被抑制时，MuV L蛋白通过CHIP（C terminal of Hsp 70-interactingprotein）介导的蛋白酶体途径被降解。高浓度的17-AAG显示出对某些细胞类型的强细胞毒性，但是组合使用Hsp 70抑制剂VER 155008增强了L蛋白的降解，允许充分降低17-AAG浓度以阻断MuV复制而具有最小的细胞毒性。Hsp 90和Hsp 70分子伴侣对L蛋白的调节也在另一种副粘病毒麻疹病毒中得到证实。总的来说，我们的数据表明，热休克蛋白90/热休克蛋白70分子伴侣机制有助于成熟的副粘病毒L蛋白，从而在形成一个成熟的RdRp复合物和有效的病毒replication.IMPORTANCE热休克蛋白90（HSP 90）是几乎普遍需要的病毒蛋白质的稳态。在这里，我们报告说，热休克蛋白90的活性是必要的腮腺炎病毒（MuV）的有效繁殖。Hsp 90的功能是维持病毒聚合酶的催化亚基，即大（L）蛋白，然后与L的聚合酶辅因子磷蛋白形成成熟的聚合酶复合物。Hsp 70与Hsp 90协同调节MuV L蛋白的生物合成。这些分子伴侣对病毒聚合酶的功能可能在副粘病毒中很常见，因为麻疹病毒的L蛋白也受到类似的调节。我们的数据提供了重要的见解副粘病毒聚合酶成熟的分子机制，以及开发新的抗病毒药物的基础。
Paramyxoviral RNAs are synthesized by a viral RNA-dependent RNA polymerase (RdRp) consisting of the large (L) protein and its cofactor phosphoprotein (P protein). The L protein is a multifunctional protein that catalyzes RNA synthesis, mRNA capping, and mRNA polyadenylation. Growing evidence shows that the stability of several paramyxovirus L proteins is regulated by heat shock protein 90 (Hsp90). In this study, we demonstrated that Hsp90 activity was important for mumps virus (MuV) replication. The Hsp90 activity was required for L-protein stability and activity because an Hsp90-specific inhibitor, 17-allylamino-17- demethoxygeldanamycin (17-AAG), destabilized the MuV L protein and suppressed viral RNA synthesis. However, once the L protein formed a mature polymerase complex with the P protein, Hsp90 activity was no longer required for the stability and activity of the L protein. When the Hsp90 activity was inhibited, the MuV L protein was degraded through the CHIP (C terminus of Hsp70-interactingprotein)-mediated proteasomal pathway. High concentrations of 17-AAG showed strong cytotoxicity to certain cell types, but combined use of an Hsp70 inhibitor, VER155008, potentiated degradation of the L protein, allowing a sufficient reduction of 17-AAG concentration to block MuV replication with minimum cytotoxicity. Regulation of the L protein by Hsp90 and Hsp70 chaperones was also demonstrated for another paramyxovirus, the measles virus. Collectively, our data show that the Hsp90/Hsp70 chaperone machinery assists in the maturation of the paramyxovirus L protein and thereby in the formation of a mature RdRp complex and efficient viral replication.IMPORTANCE Heat shock protein 90 (Hsp90) is nearly universally required for viral protein homeostasis. Here, we report that Hsp90 activity is required for efficient propagation of mumps virus (MuV). Hsp90 functions in the maintenance of the catalytic subunit of viral polymerase, the large (L) protein, prior to formation of a mature polymerase complex with the polymerase cofactor of L, phosphoprotein. Hsp70 collaborates with Hsp90 to regulate biogenesis of the MuV L protein. The functions of these chaperones on the viral polymerase may be common among paramyxoviruses because the L protein of measles virus is also similarly regulated. Our data provide important insights into the molecular mechanisms of paramyxovirus polymerase maturation as well as a basis for the development of novel antiviral drugs.