Rab6a在病毒入侵过程中支持人乳头瘤病毒从高尔基体转运的机制：BICD2/动力蛋白介导的运输

Rab6a enables BICD2/dynein-mediated trafficking of human papillomavirus from the trans-Golgi network during virus entry

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mBio

影响因子:4.7

分区:生物学2区 Top / 微生物学2区

发表日期:2024 Nov 13

作者: Jeongjoon Choi, Kaitlyn Speckhart, Billy Tsai, Daniel DiMaio

DOI: 10.1128/mbio.02811-24

摘要

Rab GTP酶调控细胞内囊泡运输，包括人乳头瘤病毒（HPV）在细胞入侵过程中的逆行运输，指导病毒从内体到高尔基体（TGN）、高尔基体和最终的细胞核。已识别出在HPV到达TGN之前起作用的Rab蛋白，但在入侵晚期作用的Rab蛋白仍不明确。本研究发现，敲低Rab6a会影响HPV的入侵，阻止病毒从TGN逃逸并妨碍病毒在高尔基体内的运输。Rab6a通过促进HPV与动力蛋白（dynein）及其适配蛋白BICD2的结合，支持HPV在TGN中的运输。L2蛋白可以在体外直接结合GTP结合态的Rab6a，过量GTP-Rab6a或GDP-Rab6均会抑制HPV的入侵，提示循环转换于GTP和GDP结合态对其功能至关重要。值得注意的是，Rab6a在感染细胞的TGN中，促进HPV与BICD2和动力蛋白的结合，但在内体中则不重要。本研究揭示了HPV感染的分子基础，包括病毒在入侵不同阶段利用不同机制与动力蛋白结合的发现，为抑制HPV感染提供潜在靶点。人乳头瘤病毒（HPV）是导致约5%人类癌症的小型非包膜DNA病毒。与其他DNA病毒类似，HPV在病毒入侵过程中迁移到细胞核以完成感染。本研究显示，HPV在病毒入侵过程中利用细胞酶Rab6a，与动力蛋白分子马达结合，促进病毒沿微管运输。Rab6a在HPV L2衣壳蛋白、动力蛋白和动力蛋白适配蛋白BICD2在TGN中的复合物形成中必不可少。这一复合物对于病毒从TGN出发运输到核内至关重要。本研究为潜在的治疗靶点提供了新线索。

Abstract

Rab GTPases control intracellular vesicular transport, including retrograde trafficking of human papillomavirus (HPV) during cell entry, guiding the virus from the endosome to the trans-Golgi network (TGN), the Golgi apparatus, and eventually the nucleus. Rab proteins have been identified that act prior to the arrival of HPV at the TGN, but Rab proteins operating in later stages of entry remain elusive. Here, we report that knockdown of Rab6a impairs HPV entry by preventing HPV exit from the TGN and impeding intra-Golgi transport of the incoming virus. Rab6a supports HPV trafficking by facilitating the association of HPV with dynein, a motor protein complex, and BICD2, a dynein adaptor, in the TGN. L2 can bind directly to GTP-Rab6a in vitro, and excess of either GTP-Rab6a or GDP-Rab6 inhibits HPV entry, suggesting that cycling between GDP-Rab6 and GTP-Rab6 is critical. Notably, Rab6a is crucial for HPV-BICD2 and HPV-dynein association in the TGN of infected cells but not in the endosome. Our findings reveal important features of the molecular basis of HPV infection, including the discovery that HPV uses different mechanisms to engage dynein at different times during entry, and identify potential targets for therapeutic approaches to inhibit HPV infection.Human papillomaviruses (HPVs) are small, non-enveloped DNA viruses that cause approximately 5% of human cancer. Like most other DNA viruses, HPV traffics to the nucleus during virus entry to successfully infect cells. We show here that HPV utilizes a cellular enzyme, Rab6a, during virus entry to engage the dynein molecular motor for transport along microtubules. Rab6a is required for complex formation between the HPV L2 capsid protein, dynein, and the dynein adaptor BICD2 in the trans-Golgi network (TGN). This complex is required for transport of the incoming virus out of the TGN as it journeys to the nucleus. Our findings identify potential targets for therapeutic approaches.