Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We recently isolated a cDNA encoding a Na+/Ca2+ exchanger from rabbit kidney that was highly similar to the canine cardiac sarcolemmal Na+/Ca2+ exchanger. In the present study, we used two different antibodies to the exchanger to identify the protein and establish its cellular and subcellular localization in the kidney. The first antibody was prepared against a fusion protein consisting of 190 amino acids of the large, presumably intracellular loop of the rabbit renal exchanger fused to the maltose-binding protein. The second was a monoclonal antibody generated against the isolated purified canine cardiac sarcolemmal exchanger. To identify the Na+/Ca2+ exchanger protein, we performed immunoblot analysis against a membrane vesicle preparation from rabbit kidney cortex. Both antibodies immunoblotted proteins of 120 and 70 kDa that are known to be associated with the exchanger. Indirect immunofluorescence revealed that both antisera labeled the basolateral surface of the majority of cells in the connecting tubule (CNT). Since the phase-dense (intercalated) cells in the CNT were not stained, this suggested that the labeled cells were CNT cells. No labeling was detected in other nephron segments with the exception of occasional faint staining of the majority cell population of the cortical collecting duct. The fact that we did not detect labeling in other nephron segments is consistent with either 1) the absence of expression of the Na+/Ca2+ exchanger in these segments, 2) the expression of the exchanger in levels below the threshold of detection of the two antibodies used in this study, or 3) the exchanger in these segments is represented by a different isoform.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Immunolocalization of the Na+/Ca2+ exchanger in rabbit kidney. 836 43

An electroneutral thiazide-sensitive Na-Cl cotransport pathway (TSC) has been localized functionally to the distal convoluted tubule (DCT), although the TSC has also been detected in the connecting tubule (CNT), the cortical collecting duct, and the medullary collecting tubule as well. The present experiments were designed to localize expression of message for the TSC in rat and human kidney. A riboprobe, generated from the mouse TSC, was used for in situ hybridization. Simultaneous immunocytochemistry, using antibodies to Tamm-Horsfall protein, band 3, and the Na+/Ca2+ exchanger, permitted delineation of specific nephron segments. In rat, message for the TSC was highly expressed in DCT cells but not elsewhere. The transition from thick ascending limb to DCT was abrupt, whereas the transition to CNT was gradual. In the more distal region of rat DCT (DCT-2), which contained few intercalated cells, both TSC message and Na+/Ca2+ exchanger immunoreactivity were present. Treatment of rats with furosemide for 5 days increased expression of TSC message within the DCT but did not induce its expression elsewhere. In humans, expression of TSC message was also highest in cells of the DCT. In humans, however, expression extended well into the CNT. These experiments indicate that the TSC is expressed predominantly by DCT cells in both rat and humans, although expression extends into the CNT cells in humans. They also show that the TSC and Na+/Ca2+ exchanger are coexpressed by a subpopulation of DCT cells near the junction with the CNT.
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PMID:Expression of the thiazide-sensitive Na-Cl cotransporter in rat and human kidney. 859 86