Immunolocalization of an inwardly rectifying K+ channel, KAB‐2 (Kir4.1), in the basolateral membrane of renal distal tubular epithelia

Abstract

Immunolocalization of KAB−2 (Kir4.1), an inwardly ectifying K+ channel with a putative ATP-binding domain, was examined in rat kidney where expression of KAB−2 mRNA was previously shown. Anti-KAB−2 antibody was raised in rabbit and then affinity-purified. An immunohistochemical study revealed that KAB-2 immunoreactivity was detected specifically in the basolateral membrane of distal tubular epithelia. Therefore, KAB-2 is the first K+ channel shown to be localized in the basolateral membrane of renal epithelia. The finding suggests that KAB-2 may contribute to supplying K+ to the Na+-K+ pump, which is abundant in the basolateral membrane of distal tubular epithelia, as well as to maintenance of the deep negative membrane potential of these cells