Schematic diagram of NHE1 Na+–H+ exchanger structure. Numbers represent predicted transmembrane domains. Phosphorylation sites are depicted by the amino acid abbreviation and residue numbers. CaM calmodulin, CHP1 calcineurin-homologous protein 1, ERK extracellular signal-related kinase, ERM ezrin/radixin/moesin, MAPK mitogen-activated protein kinase, p90RSK p90 ribosomal S6 kinase, PI(4,5)P2 phosphatidylinositol 4,5-bisphosphate, SGK1 serum and glucocorticoid-regulated kinase 1