Fig. 6. Effect of CHIF mutations on the efficiency of association with NKA. (A) Amino acid sequence of rat wild-type CHIF and of CHIF mutants with alanine substitutions of N- or C- terminal amino acids. (B) Oocytes were injected with wild-type or mutant CHIF cRNAs (0.5 ng) together with Xenopus NKA α (7 ng) and β (0.5 ng) cRNAs. After injection, oocytes were metabolically labeled for 24 h and subjected to chase periods of 24 and 72 h. Microsomes were prepared and subjected to non-denaturing immunoprecipitations with an NKA α antibody (B) or subjected directly to SDS–PAGE (C). A representative example of three similar experiments is shown.