Physiological carbon dioxide, bicarbonate, and pH sensing

In biological systems, carbon dioxide exists in equilibrium with bicarbonate and protons. The individual components of this equilibrium (i.e., CO2, HCO (3) (-) , and H+), which must be sensed to be able to maintain cellular and organismal pH, also function as signals to modulate multiple physiological functions. Yet, the molecular sensors for CO2/HCO (3) (-) /pH remained unknown until recently. Here, we review recent progress in delineating molecular and cellular mechanisms for sensing CO2, HCO (3) (-) , and pH.