Zika virus recruits karyopherin α6 for efficient replication via NS2B.

Zika virus (ZIKV) is a mosquito-borne flavivirus that caused an epidemic in the Americas in 2015-2016, accompanied by severe neurological manifestations, including congenital Zika syndrome and Guillain-Barré syndrome. Our previous data demonstrate that the protein level of karyopherin α6 (KPNA6), a transport factor in nucleocytoplasmic trafficking, increases in ZIKV-infected cells, and that KPNA6 depletion reduces ZIKV replication. Here, we found that ZIKV infection led to the relocation of KPNA6 to the perinuclear region. KPNA6 was observed to partially co-localize with double-stranded RNA, an intermediate in the replication of positive-sense, single-stranded RNA viruses. Further studies revealed that the ZIKV protein NS2B mediates the relocation of KPNA6 and that both proteins interact, as indicated by co-immunoprecipitation. The mutagenesis studies showed that KPNA6 co-precipitated NS2B via its major groove, and that, in turn, NS2B pulled down KPNA6 via its C-terminus. Furthermore, two residues, P115 and G119, in NS2B were identified as critical for interaction with KPNA6, and mutations in either residue abolished virus replication. These results demonstrate that ZIKV induces the relocation of KPNA6 via NS2B, uncovering a novel ZIKV-host interaction to recruit a host proviral factor to facilitate viral proliferation.IMPORTANCELike most other positive-sense RNA viruses, Zika virus (ZIKV) replicates in the cytoplasm; however, the mechanisms by which it recruits host factors for efficient proliferation remain elusive. Our results demonstrate that ZIKV induces the relocation of karyopherin α6 (KPNA6) to the perinuclear region, likely mediated by the viral protein NS2B. Further analysis shows that KPNA6 interacts with NS2B, with two critical residues in NS2B required for the interaction. A mutation in these two residues abolishes virus replication. Despite the absence of a predicted nuclear localization signal sequence in NS2B, this protein was found to bind the major groove of KPNA6. These findings shed light on the interaction between ZIKV and a proviral host factor, providing valuable insights that may inform the development of future antiviral strategies.