ATMHX (MAGNESIUM/PROTON EXCHANGER); cation:cation antiporter. similar to hypothetical protein OsI_008111 [Oryza sativa (indica cultivar-group)] (GB:EAY86878.1); similar to hypothetical protein OsI_008118 [Oryza sativa (indica cultivar-group)] (GB:EAY86885.1); similar to unnamed protein product [Vitis vinifera] (GB:CAO40028.1); contains InterPro domain Sodium/calcium exchanger membrane region; (InterPro:IPR004837)