Antiporters/chemistry; Antiporters/metabolism; Carrier Proteins/metabolism; Membrane Transport Proteins; Potassium/metabolism; Sodium/metabolism; trans-Golgi Network/metabolism; Amino Acid Sequence; Animals; Antiporters/genetics; CHO Cells; Carrier Proteins/chemistry; Carrier Proteins/genetics; Cloning, Molecular; Cricetinae; Humans; Hydrogen-Ion Concentration; Models, Molecular; Molecular Sequence Data; Protein Isoforms/chemistry; Protein Isoforms/genetics; Protein Isoforms/metabolism; Protein Structure, Secondary; Recombinant Proteins/chemistry; Recombinant Proteins/metabolism; Sequence Alignment; Sequence Homology, Amino Acid; Sodium-Hydrogen Exchangers; Transfection