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)

There is strong evidence that vitamin D-dependent Ca(2+)-binding proteins, i.e., calbindin-D9k and calbindin-D28k, facilitate diffusion of Ca2+ through the cytosolic compartment of renal and intestinal cells, which transport Ca2+ transcellularly. In the study presented here, parvalbumin, calbindin-D9k, and calbindin-D28k were localized precisely by immunocytochemistry in rat kidney. Antisera recognizing specifically the thick ascending loop of Henle, the connecting tubules and collecting ducts, and the intercalated cells of the collecting ducts were used to identify different cell types. In rat kidney cortex, parvalbumin and calbindin-D9k colocalized in the thick ascending loop of Henle, the distal convoluted tubule, the connecting tubule, and the intercalated cells of the collecting duct. Strikingly, in all responsive cells, parvalbumin and calbindin-D9k were exclusively present in a thin layer along the basolateral membrane. In contrast, calbindin-D28k was only present in the distal convoluted and connecting tubule, where it was evenly distributed through the cytosol. In conclusion, the exclusive localization of parvalbumin and calbindin-D9k at the basolateral membrane of immunopositive renal cells implies their involvement in the regulation of transport processes located in these membranes rather than a role as intracellular Ca2+ buffer and Ca2+ shuttle between the two opposing membranes.
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PMID:Calbindin-D9k and parvalbumin are exclusively located along basolateral membranes in rat distal nephron. 177 92

Possible sites involved in active Ca2+ transport were traced by means of immunocytochemical detection of calcium-binding proteins (CaBP) in the mammalian kidney. Antisera were raised in rabbits against calbindin-D28k from chick kidney and calbindin-D9k from bovine intestine and parvalbumin from rabbit muscle. In the rat kidney, parvalbumin and calbindin-D9k were co-localized in the loops of Henle and distal convoluted tubule. In the collecting duct their presence was restricted to the intercalated cells. In all responsive cells parvalbumin and calbindin-D9k were present exclusively along the basolateral membrane. Calbindin-D28k was only present in the outer part of the cortex, where it was localized in the distal convoluted tubule and in the connecting tubule. In these cells calbindin-D28k was evenly distributed through the cytosol. Calbindin-D28k, unlike parvalbumin and calbindin-D9k, could not be demonstrated in the loops of Henle or collecting duct.
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PMID:Immunocytochemical localization of calbindin-D28k, calbindin-D9k and parvalbumin in rat kidney. 180 13

The Ca2+-binding parvalbumin has been purified for the first time from rat kidney. Its biochemical and immunological properties were indistinguishable from the muscle counterpart. By immunohistochemical methods parvalbumin was localized in part of the distal tubule and proximal collecting duct, similar to the vitamin D-dependent Ca2+-binding protein, calbindin-28K. Parvalbumin was found to be independent of the vitamin D status of the animal since its concentration remained unchanged in kidney extracts of normal, rachitic and vitamin D-replete rats. Both proteins may be involved in the regulation of intracellular Ca2+ in kidney.
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PMID:Parvalbumin in rat kidney. Purification and localization. 351 80

Parvalbumin-immunoreactive material has been localized in various parts of the Xenopus kidney. Ciliated epithelia in the neck segment, the intermediate segment and in the peritoneal funnel, epithelial cells intermingled among flask cells in the connecting tubule, and cells in the proximal and distal tubules cells were labelled. Renal corpuscle and collecting duct cells did not exhibit parvalbumin immunoreactivities. Western-blot analysis of kidney homogenates indicated various isoforms of parvalbumin-immunoreactive proteins.
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PMID:Parvalbumin-immunoreactive material in the kidney of Xenopus laevis. 817 23

The organization of Na(+) and Ca(2+) transport pathways along the mouse distal nephron is incompletely known. We revealed by immunohistochemistry a set of Ca(2+) and Na(+) transport proteins along the mouse distal convolution. The thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC) characterized the distal convoluted tubule (DCT). The amiloride-sensitive epithelial Na(+) channel (ENaC) colocalized with NCC in late DCT (DCT2) and extended to the downstream connecting tubule (CNT) and collecting duct (CD). In early DCT (DCT1), the basolateral Ca(2+)-extruding proteins [Na(+)/Ca(2+) exchanger (NCX), plasma membrane Ca(2+)-ATPase (PCMA)] and the cytoplasmic Ca(2+)-binding protein calbindin D(28K) (CB) were found at very low levels, whereas the cytoplasmic Ca(2+)/Mg(2+)-binding protein parvalbumin was highly abundant. NCX, PMCA, and CB prevailed in DCT2 and CNT, where we located the apical epithelial Ca(2+) channel (ECaC1). Its subcellular localization changed from apical in DCT2 to exclusively cytoplasmic at the end of CNT. NCX and PMCA decreased in parallel with the fading of ECaC1 in the apical membrane. All three of them were undetectable in CD. These findings disclose DCT2 and CNT as major sites for transcellular Ca(2+) transport in the mouse distal nephron. Cellular colocalization of Ca(2+) and Na(+) transport pathways suggests their mutual interactions in transport regulation.
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PMID:Distribution of transcellular calcium and sodium transport pathways along mouse distal nephron. 1170 51

The mammalian distal nephron develops a complex assembly of specialized cell types to accomplish the fine adjustment of urinary electrolyte composition. The epithelia of the distal convoluted tubule (DCT), the connecting tubule (CNT), and the cortical collecting duct (CCD) show an axial structural heterogeneity that has been functionally elucidated by the localization of proteins involved in transepithelial ion transport. We compared the distribution of the thiazide-sensitive Na(+)-Cl(-) cotransporter (TSC), basolateral Na(+)/Ca(2+) exchanger (Na/Ca), cytosolic calcium-binding proteins calbindin D(28K) and parvalbumin, and the key enzyme for selective aldosterone actions, 11 beta-hydroxysteroid-dehydrogenase 2 (11HSD2), in the distal convolutions of the mouse. In the mouse, as opposed to the rat, we found no clear subsegmentation of the DCT into a proximal (DCT1) and a distal (DCT2) portion. The TSC was expressed along the entire DCT. Na/Ca and calbindin D(28K) were similarly expressed along most of the DCT, with minor exceptions in the initial portion of the DCT. Both were also present in the CNT. Parvalbumin was found in the entire DCT, with an occasional absence from short end portions of the DCT, and was not present in CNT. 11HSD2 was predominantly located in the CNT and CCD. Short end portions of DCT only occasionally showed the 11HSD2 signal. We also observed an overlap of 11HSD2 immunoreactivity and mRNA staining. Our observations will have implications in understanding the physiological effects of gene disruption and targeting experiments in the mouse.
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PMID:Localization of thiazide-sensitive Na(+)-Cl(-) cotransport and associated gene products in mouse DCT. 1170 51

The relationship between tubulocystic carcinoma and collecting duct carcinoma of the kidney remains controversial. Some experts are of the opinion that the tumors are related, considering tubulocystic carcinoma to be synonymous with low-grade collecting duct carcinoma. However, others maintain that the 2 are distinct, unrelated entities on the basis of morphologic features and clinical outcome. To explore the relationship between tubulocystic carcinoma and collecting duct carcinoma, we compared the expression of several gene products at the mRNA level in cohorts of each tumor subtype. Seven cases of tubulocystic carcinoma and 8 cases of collecting duct carcinoma were identified. Total RNA was isolated from formalin-fixed paraffin-embedded tissue from each case. Relative expression levels of vimentin, alpha methylacyl CoA racemase, E-cadherin, p53, CD10 antigen, parvalbumin, cytokeratin 7, and cytokeratin 19 were assessed by quantitative reverse transcription polymerase chain reaction. Tubulocystic carcinoma was characterized by relative overexpression of vimentin, p53, and alpha methylacyl CoA racemase, compared with collecting duct carcinoma (P<0.05 for each gene, t test). In general, tubulocystic carcinoma expressed higher levels of E-cadherin and CD10, whereas collecting duct carcinoma expressed higher levels of cytokeratin 19; however, these trends did not reach statistical significance in this study cohort. Tubulocystic carcinoma and collecting duct carcinoma did not express cytokeratin 7 differentially. Case-to-case variability of gene expression limited the effectiveness of any one marker to distinguish the tumor types. Our study demonstrates that tubulocystic carcinoma and collecting duct carcinoma have different expression profiles of selected genes, including vimentin, p53, and alpha methylacyl CoA racemase. Further analysis of additional cases, using quantitative reverse transcription polymerase chain reaction and immunohistochemistry, will be useful to test the reproducibility of these findings. In addition, larger studies may establish statistical differences in expression of other genes analyzed in this study. Overall, these findings support the view that tubulocystic carcinoma and collecting duct carcinoma should be considered as 2 distinct entities at the molecular level.
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PMID:Comparison of gene expression profiles in tubulocystic carcinoma and collecting duct carcinoma of the kidney. 1939 Apr 20

A 55-year-old man who presented himself with gross hematuria and right back pain was found to have a right renal mass with evidence of metastasis to the lymph nodes, bone and lung (cT1bN1M1). He underwent a transperitoneal right nephrectomy. Tumor expressed markers of CD10, P504S and CK19 immunohistochemically, so histopathological examination revealed tubulocystic carcinoma of the right kidney (pT3a). After the patient received sunitinib therapy, computed tomography revealed reduction in the size of the metastatic lung nodule and lymph nodes, indicating a partial response. He is alive without disease progression at 12 months after nephrectomy. Tubulocystic carcinoma has been referred to by Amin et al as low-grade collecting duct carcinoma and is not yet included in the World Health Organization (WHO) 2004 classification of renal tumors. The cells lining the tumor range from cuboidal to columnar and have large nuclei with low-grade changes and abundant eosinophilic or amphophilic cytoplasm. Hobnail cells are commonly seen. Immunohistochemically, tubulocystic carcinomas are strongly positive for markers of the proximal nephron (CD10, P504S) and the distal nephron (parvalbumin, CK19). Despite a low nuclear grade, tubulocystic carcinomas occasionally show progressive behavior clinically. Although there is no established salvage therapy, sunitinib was found to be effective for this patient.
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PMID:[Tubulocystic carcinoma of the kidney]. 2219 Dec 79