Expression of protein kinase C isoenzymes α, βI, and δ in subtypes of intercalated cells of mouse kidney

Abstract

Recent studies of the distribution of PKC isoenzymes in the mouse kidney demonstrated that PKC-α, -βI, and -δ are expressed in intercalated cells. The purpose of this study was to identify the intercalated cell subtypes that express the different PKC isoenzymes and determine the location of the PKC isoenzymes within these cells. Adult C57BL/6 mice kidney tissues were processed for multiple-labeling immunohistochemistry. Antibodies against the vacuolar H+-ATPase and pendrin were used to identify intercalated cell subtypes, whereas antibodies against calbindin D28Kand aquaporin-2 (AQP2) were used to identify connecting tubule cells and principal cells of the collecting duct, respectively. Within type A intercalated cells, PKC-δ was highly expressed in the apical part of the cells, whereas immunoreactivity for both PKC-α and PKC-βIwas weak. Type B intercalated cells exhibited strong expression of PKC-α, -βI, and -δ. PKC-α and -βIwere localized throughout the cytoplasm, whereas PKC-δ was restricted to the basal domain. Within non-A-non-B cells, immunoreactivity for both PKC-α and PKC-βIwas high in intensity and localized diffusely in the cytoplasm, whereas PKC-δ was localized in the apical part of the cells. None of the PKC isoenzymes (PKC-α, -βI, or -δ) were expressed in the calbindin D28K-positive connecting tubule cells. Within AQP2-positive principal cells of the collecting duct, PKC-α was expressed on the basolateral plasma membrane, but no significant staining was detected for PKC-βIand -δ. In summary, this study demonstrates distinct and differential expression patterns of PKC-α, -βI, and -δ in the three subtypes of intercalated cells in the mouse kidney.