- Peptide (C)RERSIGDVTTAPSE, corresponding to amino acid residues 54-67 of rat NHE-1 (Accession P26431). 1st extracellular loop.
- Human MCF-7 breast adenocarcinoma cells, U-87 MG glioblastoma cells and THP-1 acute monocytic leukemia cells. Rat and mouse brain membranes (1:200).
- Western blot analysis of rat brain membranes (lanes 1 and 6), mouse brain lysate (lanes 2 and 7), human MCF-7 breast adenocarcinoma cells (lanes 3 and 8), human U-87 MG glioblastoma cells (lanes 4 and 9) and human THP-1 acute monocytic leukemia cells (lanes 5 and 10):1-5. Anti-Na+/H+ Exchanger 1 (NHE-1) (extracellular) Antibody (#ANX-010), (1:200).
6-10. Anti-Na+/H+ Exchanger 1 (NHE-1) (extracellular) Antibody, preincubated with Na+/H+ Exchanger 1/NHE-1 (extracellular) Blocking Peptide (#BLP-NX010).
- Mouse brain sections (1:200).
- Human THP-1 acute monocytic leukemia cells (1:20).
- The blocking peptide is not suitable for this application.
- Human live and intact MCF-7 breast adenocarcinoma cells (1:25).
In order to function in optimal conditions, cells must maintain a close to neutral intracellular pH. They have adopted various mechanisms in order to do so, one of which is via Na+/H+ exchangers (NHEs). Genes belonging to this group are expressed along a very broad range of organisms and are essential for protecting cells against intracellular acidification1.
To date, nine genes have been identified in mammals; NHE1-9. These membrane proteins have 10-12 transmembrane domains depending on whether a splice variant is expressed and an intracellular N-terminal. The C-terminal domain can be either intracellular or extracellular, also depending whether a splice variant of the protein is involved. The C-terminal part of the protein also undergoes posttranslational modification such as phosphorylation2. Both NHE-1 and NHE-2 have an extracellular loop which is glycosylated1,3,4.
Under physiological conditions, the Na+/H+ exchanger mediates the exchange of one extracellular Na+ ion for one intracellular proton, thereby keeping the overall charge neutral1. The extracellular binding site of Na+ is not selective as it can also bind Li+ and H+ 1,5,6. K+ ions inhibit NHE-1 but have no effect on NHE-27. The activation of NHE-1 and NHE-2 is sensitive to intracellular acidic pH. Under physiological conditions, both exchangers are not active and upon a drop of intracellular pH, they are rapidly activated1,5,8.
NHE-1 expression is ubiquitous and may serve as a housekeeping gene9.