Which ion exchange is facilitated by the Na+/Ca2+ exchanger (NCX)?
Na+/Ca2+ exchanger NCX, SLC8 family with isoforms NCX1 broadly expressed in heart, brain, kidney and NCX2, NCX3 in brain and muscle, is electrogenic antiporter crucial for calcium extrusion after excitation. It operates generally with stoichiometry three Na+ imported downhill into cytoplasm in exchange for one Ca2+ exported against its gradient, generating net inward positive charge. In forward mode driven by sodium gradient, NCX rapidly lowers cytosolic Ca2+ after cardiac action potential and muscle contraction preventing overload. When intracellular Na+ rises or membrane depolarizes as durin
Ref: Hilgemann et al., Annu Rev Physiol 2013, NCX mechanism; Khananshvili, Biochem Soc Trans 2013.
