L104R, V332G, and delF100-L104 human pumps. (A–C) Representative current recordings from Na⁺-loaded oocytes, expressing L104R (A), V332G (B), and delF100-L104 (C). Left traces show the effect on holding current at −50 mV of the same experimental maneuvers shown in Fig. 4 C. Right traces show voltage pulse-evoked ouabain-sensitive currents in Na⁺ solution from the same oocytes shown on the left. Gray dashed lines indicate zero-current level.