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

Many renal diseases involving the tubular epithelium appear to preferentially affect certain nephron segments. While major portions of the nephron, such as proximal and distal convoluted tubules and collecting ducts, can be identified in the normal kidney, the distinction of diseased nephron segments can be difficult in tissue sections. Thus, to identify which nephron segments are involved in pathologic changes is usually impossible by routine histologic examination alone. Recently antibody and lectin probes that react with specific nephron segment-specific epitopes and carbohydrates, respectively, have become available. Some of these antibodies and lectins can be used on formalin-fixed, paraffin-embedded, archival tissues. Because renal tubules appear to retain their nephron segment-specific epitopes and glycoprotein moieties under most pathologic conditions, these nephron segment-specific tubular epithelial markers provide a method to study renal diseases involving the tubular system also in archival material. Such nephron segment-specific tubular epithelial markers are: the lectins, Tetragonolobus purpuras and Phaseolus vulgaris erythroagglutinin (proximal tubular markers); antibodies to low-molecular-weight cytokeratin (AE1/AE3); epithelial membrane antigen and the lectin Arachis hypogaea (distal nephron [distal convoluted tubule and collecting duct] markers); and antibodies to Tamm-Horsfall protein (labeling the thick ascending limb of Henle). We review the application of these and other renal tubular epithelial markers in the normal kidney and in various renal diseases including cystic disease of the kidney, interstitial nephritis, tubular atrophy, acute tubular necrosis, myeloma cast nephropathy, and renal tumors.
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PMID:Immunohistochemical and lectin dissection of the human nephron in health and disease. 825 Jun 94

Monoclonal antibody '4D4' was generated against a gel-purified 43-50 kDa fraction of rabbit erythrocyte (RBC) ghosts. Immunoblots of rabbit RBCs, skeletal muscle, and kidney, and of a rabbit cortical collecting duct cell line (RC.SV3) yielded broad bands of 30-70 kDa that migrated at approximately 31 kDa after deglycosylation. In kidney sections, 4D4 labeled the basal plasma membranes of the proximal tubule, medullary thick ascending limb of Henle, cortical, medullary, and papillary collecting ducts, and papillary surface epithelium, as well as the lateral membranes of alpha and beta-type intercalated cells. Antibody 4D4 was used to clone a full-length kidney cDNA, which predicted a 31 kDa immunoglobulin-like glycoprotein with high homology to mouse 'gp42' or 'basigin', human 'M6' or 'EMMPRIN', rat 'OX-47' or 'CE-9', and avian 'neurothelin', 'HT7', or '5A11'. When heterologously expressed in HeLa cells, glycosylated immunoreactive protein was expressed at the plasma membrane. In the case of the endogenous protein in RC.SV3 cells, interferon-gamma and A23187 decreased, and fetal calf serum increased, steady-state mRNA levels. Thus, this molecule exhibits a high degree of cell type-specific expression in the kidney and undergoes regulation by cytokines and serum in kidney epithelial cells.
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PMID:Cloning of the rabbit homologue of mouse 'basigin' and rat 'OX-47': kidney cell type-specific expression, and regulation in collecting duct cells. 860 97

We recently cloned an inward-rectifying K channel (Kir) cDNA, CCD-IRK3 (mKir 2.3), from a cortical collecting duct (CCD) cell line. Although this recombinant channel shares many functional properties with the "small-conductance" basolateral membrane Kir channel in the CCD, its precise subcellular localization has been difficult to elucidate by conventional immunocytochemistry. To circumvent this problem, we studied the targeting of several different epitope-tagged CCD-IRK3 in a polarized renal epithelial cell line. Either the 11-amino acid span of the vesicular stomatitis virus (VSV) G glycoprotein (P5D4 epitope) or a 6-amino acid epitope of the bovine papilloma virus capsid protein (AU1) was genetically engineered on the extreme N terminus of CCD-IRK3. As determined by patch-clamp and two-microelectrode voltage-clamp analyses in Xenopus oocytes, neither tag affected channel function; no differences in cation selectivity, barium block, single channel conductance, or open probability could be distinguished between the wild-type and the tagged constructs. MDCK cells were transfected with tagged CCD-IRK3, and several stable clonal cell lines were generated by neomycin-resistance selection. Immunoprecipitation studies with anti-P5D4 or anti-AU1 antibodies readily detected the predicted-size 50-kDa protein in the transfected cells lines but not in wild-type or vector-only (PcB6) transfected MDCK cells. As visualized by indirect immunofluorescence and confocal microscopy, both the tagged CCD-IRK3 forms were exclusively detected on the basolateral membrane. To assure that the VSV G tag was not responsible for the targeting, the P5D4 epitope modified by a site-directed mutagenesis (Y2F) to remove a potential basolateral targeting signal contained in this tag. VSV(Y2F) was also detected exclusively on the basolateral membrane, confirming bona fide IRK3 basolateral expression. These observations, with our functional studies, suggest that CCD-IRK3 may encode the small-conductance CCD basolateral K channel.
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PMID:Basolateral membrane targeting of a renal-epithelial inwardly rectifying potassium channel from the cortical collecting duct, CCD-IRK3, in MDCK cells. 937 45

Stanniocalcin (STC) is a glycoprotein hormone that was first discovered in fish and recently identified in mammals. STC immunoreactive (STCir) cells have been identified in rat kidney and there is also evidence that the hormone functions as a regulator of renal phosphate homeostasis. In the present study we have identified STCir cells and tubules in the rat kidney by correlative immunocytochemistry using antibodies to STC and specific antigenic markers (Tamm-Horsfall protein and anion exchanger-1). The cellular sites of STC gene expression were also identified by in situ hybridization. Correlative immunocytochemistry revealed that STCir was present in all proximal straight tubule cells, all cortical thick ascending limb cells, all distal convoluted tubule cells, and both principal and alpha-intercalated cells of the collecting duct system. On the other hand, in situ hybridization revealed that the STC gene was expressed only in cortical and medullary collecting duct cells. This suggests either that STC is being sequestered by segments that do not express the gene (making them putative targets of the hormone), or that STC mRNA levels were simply too low in these other segments to be detected by in situ hybridization.
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PMID:The co-localization of stanniocalcin protein, mRNA and kidney cell markers in the rat kidney. 977 61

The mechanisms responsible for renal cyst formation in congenital polycystic kidney disease (PKD) remain unknown. Changes in extracellular matrix (ECM) are regarded as an important pathogenic factor in PKD. Tenascin, an ECM glycoprotein implicated in abnormal growth in adult organs, has not been systematically evaluated in PKD. In this study, tenascin expression was studied by immunohistochemistry in the autosomal recessive polycystic kidneys of C57BL/6J (cpk/cpk) mice. Scanning electron microscopy was performed to determine the cyst types and their temporal evolution, and to establish correlations with the immunohistochemistry observations. Cystic lesions evolved in three main stages. Initially, the cysts appeared as segmental dilatations of both proximal and collecting ducts. In the second stage, the collecting duct cysts (CDCs) underwent rapid growth that led to the destruction of all other kidney elements. In the final stage, the CDCs reached their maximum size and the PKD mice died. Normal differentiated principal cells and three types of intercalated cells were present in the CDC epithelium. In all three stages an intense tenascin expression was detected selectively in the basement membranes of the cysts. In the last stage, an intense tenascin immunoreactivity was also observed in the interstitial fibrotic tissue. The abnormal presence of tenascin in the basement membranes of the cysts suggests that this glycoprotein is implicated in the pathogenesis of the cysts, possibly by stimulating cell proliferation.
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PMID:Abnormal tenascin expression in murine autosomal recessive polycystic kidneys. 1039 99

Many vertebrate transporting epithelia contain characteristic 'mitochondria-rich' cells that express high levels of a vacuolar proton-pumping ATPase (H(+)V-ATPase) on their plasma membrane and on intracellular vesicles. In the kidney cortex, A-cells and B-cells are involved in proton secretion and bicarbonate secretion, respectively, in the distal nephron and collecting duct. A-cells have an H(+)V-ATPase on their apical plasma membrane and on intracellular vesicles, whereas the cellular location of the H(+)V-ATPase can be apical, basolateral, bipolar or diffuse in B-cells. The rat epididymis and vas deferens also contain a distinct population of H(+)V-ATPase-rich epithelial cells. These cells are involved in generating a low luminal pH, which is involved in sperm maturation and in maintaining sperm in an immotile state during their passage through the epididymis and vas deferens. In both kidney and reproductive tract, H(+)V-ATPase-rich cells have a high rate of apical membrane recycling. H(+)V-ATPase molecules are transported between the cell surface and the cytoplasm in vesicles that have a well-defined 'coat' structure formed of the peripheral V(1) subunits of the H(+)V-ATPase. In addition, we propose that B-type intercalated cells have a transcytotic pathway that enables them to shuttle H(+)V-ATPase molecules from apical to basolateral plasma membrane domains. This hypothesis is supported by data showing that A-cells and B-cells have different intracellular trafficking pathways for LGP120, a lysosomal glycoprotein. LGP120 was found both on the basolateral plasma membrane and in lysosomes in B-cells, whereas no LGP120 was detectable in the plasma membrane of A-cells. We propose that the 'polarity reversal' of the H(+)V-ATPase in B-intercalated cells is mediated by a physiologically regulated transcytotic pathway that may be similar to that existing in some other cell types.
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PMID:H(+)V-ATPase-dependent luminal acidification in the kidney collecting duct and the epididymis/vas deferens: vesicle recycling and transcytotic pathways. 1060 Jun 82

UT-A1 is an extremely hydrophobic 929-amino acid integral membrane protein, expressed in the renal inner medullary collecting duct, with a central role in the urinary concentrating mechanism. Previous immunoblotting studies in rats have revealed that UT-A1 is present in kidney in 97- and 117-kDa monomeric forms and that the relative abundance of the two forms is altered by vasopressin treatment and other treatments that altered urinary inner medullary urea concentration. The present studies were carried out using protein chemistry techniques to determine the origin of the two forms. Peptide-directed polyclonal antibodies targeted to five sites along the polypeptide sequence from the NH2 to the COOH terminus labeled both forms, thus failing to demonstrate a significant deletion in the primary amino acid chain. The 97- and 117-kDa monomeric forms were both reduced to 88 kDa by deglycosylation with N-glycosidase F, indicating that a single polypeptide chain is glycosylated to two different extents. Studies using nonionic detergents for membrane solubilization or using homobifunctional cross-linkers demonstrated that UT-A1 exists as a 206-kDa protein complex in native kidney membranes. The mobility of this complex was also increased by deglycosylation. Both the 97- and 117-kDa proteins, as well as the 206-kDa complex, were immunoprecipitated with UT-A1 antibodies. We conclude that UT-A1 is a glycoprotein and that the two monomeric forms (97 and 117 kDa) in inner medullary collecting duct are the consequence of different states of glycosylation.
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PMID:97- and 117-kDa forms of collecting duct urea transporter UT-A1 are due to different states of glycosylation. 1139 54

CD9 is a glycoprotein that is abundant in hematopoietic cells. Recently, it has been reported that CD9 is also present in the human kidney. In this article, we investigated the expression of CD9 using an immunohistochemical technique. We also studied the expression of CD9 protein and messenger RNA (mRNA) in tissue samples of some renal tumors using immunoblotting and reverse-transcription polymerase chain reaction (RT-PCR) analysis. Immunohistochemically, all tumors of papillary and chromophobe renal cell carcinomas (RCCs) and oncocytomas expressed CD9. In addition, CD9 was expressed in 31 of 66 conventional RCCs and 1 of 4 collecting duct carcinomas. On immunoelectron microscopy, CD9 was identified on the plasma membrane of a conventional RCC. The presence of CD9 protein in normal kidneys and various renal tumors, except for a collecting duct carcinoma and an oncocytoma, was confirmed by immunoblotting. On RT-PCR analysis, the expression of CD9 mRNA was observed in 1 normal kidney, 2 conventional RCCs, and 1 oncocytoma. The frequency of immunohistochemical CD9 positivity was significantly higher in papillary and chromophobe RCCs than in collecting duct carcinomas and conventional RCCs, respectively. These results suggest that CD9 may be a beneficial marker in the differential diagnosis between papillary RCCs and collecting duct carcinomas and also between chromophobe and conventional RCCs.
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PMID:Expression of CD9/motility-related protein 1 (MRP-1) in renal parenchymal neoplasms: consistent expression in papillary and chromophobe renal cell carcinomas. 1167 34

Stanniocalcin is a glycoprotein hormone first described in fish as a hypocalcemic factor, and recently its mammalian counterpart has been identified. Localization of stanniocalcin 1 and its regulation of expression were determined in control and 1alpha,25-dihydroxyvitamin D3-treated rats. Immunoreactivity for stanniocalcin 1 was detected in the loop of Henle, macula densa cells, distal convoluted tubule (DCT), and cortical collecting duct (CCD), and also faintly in the medullary collecting ducts. Pre-embedding electron-microscopic immunocytochemistry revealed stanniocalcin 1 in the apical membrane of cells of loop of Henle, DCT, and principal cells of CCD. The expression of stanniocalcin 1 was increased by elevated plasma calcium via 1alpha,25-dihydroxyvitamin D3 treatment. In conclusion, stanniocalcin 1 was expressed in the apical membrane of distal nephron segments and enhanced by vitamin D3.
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PMID:Distribution of stanniocalcin 1 in rat kidney and its regulation by vitamin D3. 1170 3

Ammonia is both produced and transported by renal epithelial cells, and it regulates renal ion transport. Recent studies have identified a family of putative ammonium transporters; mRNA for two members of this family, Rh B-glycoprotein (RhBG) and Rh C-glycoprotein (RhCG), is expressed in the kidney. The purpose of this study was to determine the cellular location of RhBG and RhCG protein in the mouse kidney. We generated RhBG- and RhCG-specific anti-peptide antibodies. Immunoblot analysis confirmed that both proteins were expressed in the mouse kidney. RhBG localization with immunohistochemistry revealed discrete basolateral labeling in the connecting segment (CNT) and in the majority of initial collecting tubule (ICT) and cortical collecting duct (CCD) cells. In the outer medullary collecting duct (OMCD) and inner medullary collecting duct (IMCD) only a subpopulation of cells exhibited basolateral immunoreactivity. Colocalization of RhBG with carbonic anhydrase II, the thiazide-sensitive transporter, and the anion exchangers AE1 and pendrin demonstrated RhBG immunoreactivity in all CNT cells and all CCD and ICT principal cells. In the ICT and CCD, basolateral RhBG immunoreactivity is also present in A-type intercalated cells but not in pendrin-positive CCD intercalated cells. In the OMCD and IMCD, only intercalated cells exhibit RhBG immunoreactivity. Immunoreactivity for a second putative ammonium transporter, RhCG, was present in the apical region of cells with almost the same distribution as RhBG. However, RhCG immunoreactivity was present in all CCD cells, and it was present in outer stripe OMCD principal cells, in addition to OMCD and IMCD intercalated cells. Thus the majority of RhBG and RhCG protein expression is present in the same epithelial cell types in the CNT and collecting duct but with opposite polarity. These findings suggest that RhBG and RhCG may play important and cell-specific roles in ammonium transport and signaling in these regions of the kidney.
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PMID:Localization of the ammonium transporter proteins RhBG and RhCG in mouse kidney. 1238 12


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