The yeast Nha1p Na+, K+/H+ antiporter has a house-keeping role in pH and cation homeostasis. It is also needed
to alleviate excess Na+ or K+ from the cytoplasm under high external concentrations of these cations. Erv14p, a
putative cargo receptor for transmembrane proteins is required for trafficking of Nha1p from the endoplasmic
reticulum to the plasma membrane. Sensitivity to high Na+ concentrations of the erv14 mutant associated to
the intracellular mislocalization of Nha1p-GFP, together with a lower Na+ efflux, indicate the involvement of
this mutual association to accomplish the survival of the yeast cell upon sodium stress. This observation is supported
by the protein–protein interaction between Erv14p and Nha1p detected by the mating-based Split Ubiquitin
System and co-immunoprecipitation assays. Our results indicate that even though Erv14p interacts with
Nha1p through the TMD, the C-terminal is important not only for the efficient delivery of Nha1p to the plasma
membrane but also for its dimerization to accomplish its role in yeast salt tolerance.
© 2015 Elsevier