Fig. 6. Co-immunoprecipitation of Na⁺/K⁺-ATPase (NKA) with pFXYD protein (A), and pFXYD with NKA (B). pFXYD and NKA were immunoprecipitated from gill total lysates of freshwater pufferfish by primary antibodies, then the immune complexes were analyzed by SDS-PAGE and subsequent immunoblotting for NKA and pFXYD protein, respectively. Immunoreactive bands of NKA and FXYD were detected at 100 kDa (A) and 13 kDa (B), respectively. In B, the 55 kDa band in lane 3 is the IgG heavy chain of pFXYD antibody. M, markers; lane 1, western blot detection of the opposite antibody (experimental group); lane 2, negative control; lane 3, positive control of immunoblot using the same antibody with immunoprecipitation.