K(+)/H(+) antiporter involved in K(+) homeostasis and osmotic adjustment. Expressed in shoots and roots. Up-regulated by low K(+) stress and down-regulated by high K(+). May be due to a competing acceptor splice site. Belongs to the monovalent cation:proton antiporter 2 (CPA2) transporter (TC 2.A.37) family. KEA (TC 2.A.37.1) subfamily.