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

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 that act prior to the arrival of HPV to the TGN have been identified, but Rab proteins operating in later stages of entry remain elusive. Here, we report that knockdown of Rab6a impairs HPV entry by impeding intra-Golgi transport of the incoming virus, resulting in HPV accumulation in the TGN. Rab6a supports HPV trafficking by facilitating the association of HPV with dynein, a motor protein complex, and BICD2, a dynein adaptor. 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 the HPV-dynein association in the endosome does not require Rab6a. Our findings reveal an important feature of the molecular basis of intra-Golgi trafficking of HPV and identify potential targets for therapeutic approaches to inhibit HPV infection.