Fig. 5. AeNHE3 rescues S. cerevisiae NHA1 function when heterologously expressed in mutant cells lacking endogenous Na⁺ efflux and Na⁺/H⁺ exchanger proteins. Yeast cells were grown in alkali cation free-AP medium overnight, and cell density adjusted to an OD₆₀₀=1. Tenfold serial decimal dilutions were spotted on: (A) AP plates containing 50 mmol l^-1 NaCl, and (B) minimal media plates containing 100 µg ml^-1 Hygromycin B. Growth was recorded after 4 days in (A), and 3 days in (B). Strain G19 was used as the NHA1, NHX1 wild-type control; nha1, nhx1 is the AXT3 strain. AeNHE3 expression was under galactose induction; all controls were transformed with an empty vector.