PH Regulation

The literature suggests that a antiporters, specifically a Na+/H+ antiporter, are responsible for controlling pH within cells. 12

As noted in a 2002 article, "Proton fluxes at the plasma membrane are regulated by several families of ion exchangers, including the Na+/H+ exchangers(NHEs) and HCO3 transporters, such as the Na+/HCO-3- cotransporters (NBCs), Cl−/HCO−3 exchangers (AEs), and the Na+ driven Cl−/HCO−3- exchanger (NDAE).

NHEs are the most widely discussed antiporters in relation to pH. There are six members of the NHE family and they are evolutionarily conserved. NHE1 is responsible for "pH and cell-volume homeostasis." It is made up of approximately 820 amino acids and is similar in structure to other ion exchangers.

Key ion

The main antiporter in bacteria has been identified as NhaA. 2 This protein "uses the electrochemical proton gradient maintained across the bacterial membrane and excretes Na+ in exchange for a 'downhill' flow of protons into the cell." 2 Though NhaA plays a role in changing the pH of a cell, it is actually regulated by pH. It is down-regulated in an acidic pH.