Required for constitutive membrane traffic. Inhibits GTPase-stimulated Na(+)/H(+) exchange. Also inhibits calcineurin phosphatase activity. Required for activity of SLC9A1/NHE1.
Ubiquitously expressed. Has been found in fetal eye, lung, liver, muscle, heart, kidney, thymus and spleen.
Contains 4 EF-hand domains.
Both N-myristoylation and calcium-mediated conformational changes are essential for its function in exocytic traffic. Phosphorylated; decreased phosphorylation is associated with an increase in exchange activity. The phosphorylation state may regulate the binding to NHE1.