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)

Kidney cells of the marine stickleback Spinachia have been studied with histochemical methods for the demonstration of glycoconjugates. The fine structure of epithelial cells is described. Mucus threads in the nephronic tubule of sexually mature consist of neutral glycoprotein which corresponds with the secretory granules in proximal tubule segment II cells. Large lysosome-like inclusions, which also react with PAS, are present in many P II cells. All cells of the collecting duct epithelium differentiate into mucous cells in male Spinachia. The nature of their secretory products, which are well preserved by freeze-drying, is discussed. Sialylated glycoprotein is present in mucus granules and sulphated glycoprotein can be demonstrated at the apex of collecting duct cells. Collecting duct cell mucus can be digested with testicular hyaluronidase indicating that proteoglycans may be involved in the structure of macromolecules. The observations are compared with studies of mucus production in the urinary apparatus of several other vertebrates.
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PMID:The kidney of a teleost, Spinachia spinachia. II. Histochemical identification of sialic acid-containing glycoprotein and fine structure of mucus secreting cells. 58 60

The water permeability of the kidney collecting duct epithelium is regulated by vasopressin (VP)-induced recycling of water channels between an intracellular vesicular compartment and the plasma membrane of principal cells. To test whether the water channels pass through an acidic endosomal compartment during the endocytic portion of this pathway, we measured ATP-dependent acidification of FITC-dextran-labeled endosomes in isolated microsomal fractions from different regions of Brattleboro rat kidneys. Both VP-deficient controls and rat treated with exogenous VP were examined. ATP-dependent acidification was not detectable in endosomes containing water channels from distal papilla (osmotic water permeability Pf = 0.038 +/- 0.004 cm/s). In contrast, the addition of ATP resulted in a strong acidification of renal cortical endosomes (pHmin = 5.8, initial rate = 0.18-0.25 pH U/s). Acidification of cortical endosomes was reversed with nigericin and strongly inhibited by N-ethyl-maleimide. Passive proton permeability was similar and low in both cortical and papillary endosomes from rats treated or not treated with VP. The fraction of labeled endosomes present in microsomal preparations was determined by fluorescence imaging microscopy of microsomes nonspecifically bound to poly-l-lysine-coated coverslips and was 25% in cortical preparations compared to 14% (+VP) and 9% (-VP) in papillary preparations. The fraction of cortical endosomes was enriched 1.5-fold by immunoabsorption to coverslips coated with mAbs against the bovine vacuolar proton pump. In contrast, the fraction of papillary endosomes was depleted more than twofold by immunoabsorption to identical coverslips. Finally, sections of distal papilla stained with antibodies against the lysosomal glycoprotein LGP120 showed that most of the entrapped FITC-dextran did not colocalize with this lysosomal protein. These results demonstrate that vesicles which internalize water channels in kidney collecting duct principal cells lack functional proton pumps, and do not deliver the bulk of their FITC-dextran content to lysosomes. The data suggest that the principal cell contains a specialized nonacidic apical endocytic compartment which functions primarily to recycle membrane components, including water channels, to the plasma membrane.
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PMID:Endocytic vesicles from renal papilla which retrieve the vasopressin-sensitive water channel do not contain a functional H+ ATPase. 169 62

Sulfated glycoprotein-2 (SGP-2) is a secreted, dimeric, glycosylated protein synthesized by a number of different epithelial cell types. Although its function is not yet understood, SGP-2 has been hypothesized to be involved in such diverse processes as the promotion of cell-cell interactions, spermatogenesis, modulation of the complement system, and programmed cell death. We have now found that the SGP-2 gene is developmentally regulated in the mouse kidney. SGP-2 gene expression is first detected in the condensing nephrogenic mesenchyme and is subsequently down-regulated during the maturation of the glomerular epithelia, proximal tubules, and collecting ducts. SGP-2 continues to be expressed in the mature kidney in distal tubules and in the urothelial lining of the calyx and papilla. We have also examined the expression of the SGP-2 gene in polycystic kidneys of the C57BL/6J-cpk mouse, a model of autosomal recessive polycystic kidney disease in which there is development of epithelial-lined cysts arising primarily from the collecting duct system. Abnormally high levels of SGP-2 mRNA were found in the cyst wall epithelium of polycystic kidneys. The expression of the SGP-2 gene in normal development suggests that it plays a role in differentiating epithelial structures; and the abnormally high levels of SGP-2 gene expression in polycystic kidneys suggests that the cells lining cysts are not fully differentiated. It is possible, therefore, that polycystic kidney disease is caused by a defective developmental process in which there is a delay in terminal differentiation.
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PMID:The SGP-2 gene is developmentally regulated in the mouse kidney and abnormally expressed in collecting duct cysts in polycystic kidney disease. 186 65

cDNA clones coding for the gp 80 heterodimeric glycoprotein complex secreted constitutively at the apical surface of Madin-Darby canine kidney (MDCK) cells have been isolated from MDCK cDNA libraries in lambda gt11 and lambda gt10. The cloned sequences encode a polypeptide chain of 445 amino acids. The deduced amino acid sequence of the gp 80 protein reveals 80% homology to rat SGP-2, a major secretory protein of the testes epithelium and 83% homology to SP-40,40, a human complement-associated protein. SGP-2 and SP-40,40 have been proposed to be serum and seminal forms of the same protein. The sequence homology as well as the results of Southern and Northern blot analyses and immunological studies suggest that gp 80 is the canine homolog of the rat SGP-2 and the human SP-40,40. The protein is expressed in the embryonic kidney already early during organogenesis. In the adult kidney the protein has been localized along the luminal surfaces of the proximal and distal tubule and the collecting duct cells.
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PMID:Molecular cloning of gp 80, a glycoprotein complex secreted by kidney cells in vitro and in vivo. A link to the reproductive system and to the complement cascade. 203 78

Tamm-Horsfall protein (THP) has been previously detected in cells of the thick ascending limb of Henle's loop (TAL) of different mammalian species using immunocytochemical methods. A nearly complete identity between THP and uromodulin, an immunosuppressive glycoprotein present in the urine of pregnant females, has been established recently. This paper describes the cellular location of THP mRNA by high-resolution in situ hybridization using a [35S]-labeled human uromodulin cRNA (antisense-) probe of a length of 665 base pairs. Control experiments were performed using an mRNA (sense-) probe of the same length. The probe was hybridized to frozen sections of the rat kidney. THP mRNA distribution in the kidney was found to be homologous to the immunocytochemical labeling pattern: Autoradiographic signal was present along the entire length of the TAL including the post-macula segment which leads to the distal convoluted tubule. Tubular cells of the macula densa were negative. Labeling intensity of the TAL epithelium was found to increase from the origin of the TAL at the transition between inner and outer medulla to its end beyond the macula densa. Labeling of the medullary segment in the inner stripe was weak, whereas outer medullary and cortical segments very strongly expressed THP mRNA. The glomerulus, the portions of the nephron proximal to the TAL, the distal convoluted tubule as well as the collecting duct system were negative.
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PMID:Tamm-Horsfall protein-mRNA synthesis is localized to the thick ascending limb of Henle's loop in rat kidney. 228 15

Immunocytochemical detection of carbonic anhydrase (CA II), (Na+-K+)-ATPase and the anion channel (band 3) glycoprotein was used to study structural and functional heterogeneity of cells lining the collecting ducts, especially of intercalated cells, in the rat kidney. High content of CA II was found in intercalated cells as determined by morphology, although a weak diffuse cytoplasmic staining of this enzyme could be observed also in a subpopulation of principal cells. (Na+-K+)-ATPase could be detected exclusively in principal cells, whereas basolateral band 3 immunoreactivity was seen only in a subpopulation of intercalated cells. Double immunostaining experiments revealed that the weak cytoplasmic type of CA II and basolateral (Na+-K+)-ATPase immunoreactivities were colocalized in 20 to 30% (depending on the segment studied) of the collecting duct epithelial cells but, in contrast, cells rich in CA II or those with basal band 3 immunoreactivity seldom contained (Na+-K+)-ATPase. Instead, band 3 glycoprotein and the abundant CA II were colocalized in 20 to 35% of the cells in various segments of collecting ducts, whereas, band 3 and weak cytoplasmic CA II were seldom seen in the same cells. The results show that the current approach is useful for identifying and characterizing two distinct subpopulations of intercalated cells, both rich in CA II but differing in respect to the presence or absence of band 3 glycoprotein. On the basis of physiologic and biochemical data of the functions of these transport proteins we propose that the subpopulations of intercalated cells thus identified represent the acidifying and alkalinizing subtypes, respectively.
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PMID:Immunocytochemical characterization of carbonic anhydrase-rich cells in the rat kidney collecting duct. 244 Nov 37

A plasma membrane glycoprotein (gp110) involved in cellular adhesion was studied in Wistar and Fischer rats. For quantitative analysis of the gp110 molecule a sandwich-ELISA was used. High quantities of gp110 were found especially in the liver, small intestine, submandibular gland and lung. The distribution and localization of the gp110 were investigated by immunohistochemistry utilizing soluble complexes of alkaline phosphatase and monoclonal anti-alkaline phosphatase antibodies. Immunoreactivity was present in plasma membranes of vascular endothelial cells of some organs. Furthermore, immunostaining also occurred in plasma membranes of lymphocytes, exocrine gland cells, excretory duct cells, hepatocytes, epithelial cells of the small intestine, kidney and vesicular gland and in the cytoplasm of renal connecting and collecting duct cells. The localization of gp110 in the luminal domain of the plasma membrane at many sites suggests that this glycoprotein is also involved in processes distinct from cell adhesion.
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PMID:Localization of a putative cell adhesion molecule (gp110) in Wistar and Fischer rat tissues. 261 47

Highly specific antibodies against vital enzymes of the collecting ducts were used to study the appearance of cell type specific enzyme profiles in developing rat kidneys. (Na+K)-ATPase, the abundant enzyme of principal cells, could be detected early in utero in most collecting duct cells. However, the characteristic basolateral polarization of this enzyme did not appear until the first hours after birth. After this, the relative amount of (Na+K)-ATPase immunoreactive cells along collecting ducts decreased steadily, to reach the amount found in adult rat kidneys by the 30th postnatal day. Carbonic anhydrase immunoreactivity characteristic for intercalated cells was not detectable in fetal kidneys, but appeared soon after birth, with steadily increasing numbers of cells that were positive. Interestingly, immunoreactive band 3 glycoprotein (anion channel protein of erythrocytes) did not appear until the 5th day of life, with only a slowly increasing number of cells positive for this probe. These results, showing the sequential appearance of cell type-specific enzyme reactivities along collecting ducts, likely reflect a similar pattern of functional development of the respective main cell types. These results may provide an explanation for physiologic neonatal acidosis, as the enzyme profile associated with proton secretion was seen to appear slowly during the first weeks of life in a distinct manner.
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PMID:Ontogeny of cell type-specific enzyme reactivities in kidney collecting ducts. 282 8

The morphologically heterogeneous cell populations in the collecting ducts of the rat kidney were studied using immunocytochemical detection of Na+-K+-ATPase and the anion channel (band 3) glycoprotein. Both enzymes were localized to the basal aspect of separate and morphologically distinct subpopulations of cells in various segments of the collecting duct. Na+-K+-ATPase appeared to be present exclusively in principal cells as identified by their morphology, whereas band 3 antibodies reacted only with intercalated cells. However, 5-20% of cells with the morphological characteristics of intercalated cells failed to react with either antisera in various segments of collecting ducts. As band 3 glycoprotein serves in exchanging intracellular bicarbonate for chloride, it is highly likely that the cells positive for this antigen secrete protons. The method introduced here appears thus useful for distinguishing between principal and intercalated cells by differences in their enzyme content and further for revealing two subpopulations of intercalated cells. This method promises to provide a useful approach for studying the principal and intercalated cell populations in various metabolic states.
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PMID:Three distinct cell populations in rat kidney collecting duct. 303 55

The present experiments report the existence of an apico-basal plasma membrane shuttle in cultured renal collecting duct principal cell epithelium. Apical and basal perfusion under isotonic conditions, 290 mosm phosphate-buffered saline (PBS), has no effect on the shape of the epithelium. In contrast, gradient perfusion of the epithelium with 75 mosm PBS on the apical side and 290 mosm PBS on the basal side for 10 min alters the morphology of the epithelium by causing the originally columnar epithelial cells to become lower, the intercellular spaces to dilate, and the intracellular vesicles to enlarge. Perfusion of the epithelium with isotonic PBS in the presence of electron-dense cellular markers such as gold-coupled GPCDI antibody, recognizing a glycoprotein in the plasma membrane of collecting duct cells (W.W. Minuth, G. Lauer, S. Bachman and W. Kriz, Histochemistry 80:171-182, 1984), cationized ferritin (CF), horseradish peroxidase (HRP) and native ferritin (NF) for 10 min reveals their binding at the apical plasma membrane. Little endocytosis is observable. However, after labeling the luminal side by the cellular markers and following exposure to apical hypotonicity, 75 mosm PBS for 10 min, endocytosis of all markers is enhanced to a high degree. Furthermore, the gold-coupled GPCDI antibody and cationized ferritin are transported within vesicles unidirectionally through the epithelium and are exocytosed at the basolateral aspect, indicating the retrieval and possible translocation of apical plasma membrane. In contrast, volume markers such as NF and HRP are also endocytosed under osmotic gradient exposure, but are not seen to be transcytosed. Therefore, the function of this membrane pathway seems not to be related to water reabsorption, but may be part of a cellular response as protection against the osmotic gradient.
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PMID:Apico-basal osmotic gradient induces transcytosis in cultured renal collecting duct epithelium. 336 67


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