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

Abstract

Immunolocalization of KAU-2 (Kir4

An ATP-Dependent Inwardly Rectifying Potassium Channel, KAB-2 (Kir4.1), in Cochlear Stria Vascularis of Inner Ear: Its Specific Subcellular Localization and Correlation with the Formation of Endocochlear Potential

“…To sustain high activity of Na ϩ ,K ϩ -ATPase and Na ϩ ,K ϩ ,2Cl Ϫ cotransporter, K ϩ secretion through K AB -2 into interlayer space from marginal cells may be mandatory. This function of K AB -2 in stria vascularis is comparable with that in renal distal tubules, where K AB -2 is colocalized with Na ϩ ,K ϩ -ATPase at the basolateral membrane of renal epithelial cells (Ito et al, 1996). K AB -2 in renal epithelial cells probably secretes K ϩ ions into the narrow spaces surrounded by the infoldings of epithelial basolateral membrane to sustain the activity of Na ϩ ,K ϩ -ATPase (for review, see Giebisch, 1995).…”

“…Affinity-purified anti-K AB -2C2 antibody, which was raised against the amino acid sequence in the C-terminal end of rat K AB -2 (EKEGSALS-VRISNV), was prepared as reported previously (Ito et al, 1996). Anti-K AB -2C2 antibody can recognize both rat and mouse K AB -2, because the amino acid sequence in the C-terminal end of mouse K AB -2 is identical with that of rat K AB -2 (our unpublished observations).…”

“…Slice immunohistochemistry was performed as described previously (Ito et al, 1996). The cryosections were incubated with anti-K AB -2C2 antibody (0.08 g /ml) and treated with ABC kit (Vector Laboratories) or fluorescein isothiocyanate (FITC)-labeled anti-rabbit antibody.…”

“…We have developed a specific polyclonal antibody against the C-terminal region of K AB -2 subunit (anti-K AB -2C2 antibody) (Ito et al, 1996). We examined the distribution of K AB -2 in rat cochlea using this antibody (Fig.…”

“…Localization mechanism of K AB -2 at basolateral membrane of epithelia K AB -2 immunoreactivity was detected specifically at the basolateral membrane of cochlear marginal cells and distal convoluted renal epithelial cells (Ito et al, 1996). Recently, several mechanisms that determine subcellular localization of membrane proteins have been identified (Rothmann and Wieland, 1996).…”