Kinesin-1 Regulates Endocytic Trafficking of Classical Swine Fever Virus along Acetylated Microtubules.

Classical swine fever (CSF), caused by classical swine fever virus (CSFV), is an important and highly infectious pig disease worldwide. Kinesin-1, a molecular motor responsible for transporting cargo along the microtubule, has been demonstrated to be involved in the infections of diverse viruses. However, the role of kinesin-1 in the CSFV life cycle remains unknown. Here, we first found that Kif5B played a positive role in CSFV entry by knockdown or overexpression of Kif5B. Subsequently, we showed that Kif5B was associated with the endosomal and lysosomal trafficking of CSFV in the early stage of CSFV infection, which was reflected by the colocalization of Kif5B and Rab7, Rab11, or Lamp1. Interestingly, trichostatin A (TSA) treatment promoted CSFV proliferation, suggesting that microtubule acetylation facilitated CSFV endocytosis. The results of chemical inhibitors and RNA interference showed that Rac1 and Cdc42 induced microtubule acetylation after CSFV infection. Furthermore, confocal microscopy revealed that cooperation between Kif5B and dynein help CSFV particles move in both directions along microtubules. Collectively, our study shed light on the role of kinesin motor Kif5B in CSFV endocytic trafficking, indicating the dynein/kinesin-mediated bidirectional CSFV movement. The elucidation of this study provides the foundation for developing CSFV antiviral drugs.