NHX4 (sodium proton exchanger 4); sodium:hydrogen antiporter. Identical to Sodium/hydrogen exchanger 3 (NHX3) [Arabidopsis Thaliana] (GB:Q84WG1;GB:Q9SQU0); similar to NHX2 (sodium proton exchanger 2), sodium:hydrogen antiporter [Arabidopsis thaliana] (TAIR:AT3G05030.1); similar to Na H-antiportor [Nierembergia caerulea] (GB:BAB56106.1); similar to hypothetical protein [Vitis vinifera] (GB:CAN61480.1); similar to Na H-antiportor [Petunia x hybrida] (GB:BAB56105.1); contains InterPro domain Sodium/hydrogen exchanger; (InterPro:IPR006153); contains InterPro domain Sodium/hydrogen exchanger subfamily; (InterPro:IPR004709)