NHE2, also known as SLC9A2, is a protein-coding gene mainly at the top of gastrointestinal epithelial cells. It mainly encodes a member of the sodium-hydrogen exchanger (NHE) protein family, which is localized to the apical membrane and is easily degraded by lysosomes, resulting in a short half-life. NHE2 is involved in sodium ion transport by exchanging intracellular hydrogen ions into external sodium ions, and helps in the regulation of cell pH and volume to eliminate acids produced by active metabolism or against adverse environmental conditions. NHE2 is widely distributed in tissues of the gastrointestinal tract, kidney, heart, testes, uterus, and adrenal glands (PMID: 37688782). The observed molecular weight of NHE2 is 70 kDa, which might be the unmodified form of NHE2 (PMID: 10444453, 10666043).