Vacuolar cation/proton exchanger (CAX). Translocates Ca(2+) and other metal ions into vacuoles using the proton gradient formed by H(+)-ATPase and H(+)-pyrophosphatase (By similarity). Tonoplast. Belongs to the Ca(2+):cation antiporter (CaCA) (TC 2.A.19) family. Cation/proton exchanger (CAX) subfamily. The predicted gene has been split into 2 genes: At1g55730 and At1g55740.