Provided herein are methods of improving electrolyte balance across a cell membrane and treating pathophysiological conditions associated with electrolyte imbalance. Improvement or treatment is effected by ontacting the cell or administering a peptide modulator that increases the surface expression of Ca2+-activated potassium channels. The peptide modulator may comprise a C-terminal sequence such as in SEQ ID NOS: 9 or 10 or a conservative mutant thereof such as in SEQ ID NOS: 12-20 or modifications thereof.