Sodium/Hydrogen Exchanger 7 (NHE7)

Sequence analysis predicted that the 725-amino acid protein, which is 70% identical to NHE6 (SLC9A6), contains 12 N-terminal alpha-helical hydrophobic membrane-spanning segments followed by a C-terminal hydrophilic cytoplasmic tail. Northern blot analysis revealed ubiquitous expression of 9.5-, 7.5-, and 3.0-kb SLC9A7 transcripts, with highest expression in putamen and occipital lobe of brain, skeletal muscle, and secretory tissues. Immunoblot analysis showed ponasterone A-regulated expression of approximately 180- and 80-kD proteins. Confocal microscopy demonstrated expression predominantly in the trans-Golgi network. Functional analysis indicated that SLC9A7 mediates the amiloride-insensitive, benzamil-sensitive influx of sodium or potassium for hydrogen.