IMMUNOLOCALIZATION OF AN INWARDLY RECTIFYING K-AB-2 (KIR4.1), IN THE BASOLATERAL MEMBRANE OF RENAL DISTAL TUBULAR EPITHELIA( CHANNEL, K)

Immunolocalization of K-AB-2 (Kir4.1), an inwardly rectifying K+ chann el with a putative ATP-binding domain, was examined in rat kidney wher e expression of K-AB-2 mRNA was previously shown, Anti-K-AB-2 antibody was raised in rabbit and then affinity-purified. An immunohistochemic al study revealed that K-AB-2 immunoreactivity was detected specifical ly in the basolateral membrane of distal tubular epithelia, Therefore, K-AB-2 is the first K+ channel shown to be localized in the basolater al membrane of renal epithelia, The finding suggests that K-AB-2 may c ontribute to supplying K+ to the Na+-K+ pump, which is abundant in the basolateral membrane of distal tubular epithelia, as well as to maint enance of the deep negative membrane potential of these cells.