CHIKV CP interacts with karyopherins. (A) Ni-NTA pull-down assay with purified CHIKV CP and cell extract containing the FLAG-tagged karyopherins α1, α2, α3, and α4. Complexes consisting of karyopherin and CHIKV CP were detected with an anti-FLAG antibody. The lower panel shows the CP probed with an anti-His antibody. (B) Immunoprecipitations after HEK293 cells were transfected with FLAG-tagged Karα4 and pCHIKV-CP-EGFP using anti-FLAG or control antibody. The samples were subjected to SDS-PAGE and analyzed by Western blotting with an anti-GFP antibody. The upper panel shows Karα4 probed with anti-FLAG antibody.