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)

Nitric oxide (NO) is a messenger molecule that is produced from L-arginine by NO synthase (NOS). Some NOS isoforms are present in cells constitutively, whereas others can be induced by cytokines. Recent evidence suggests that NO inhibits intracellular pH regulation by the vacuolar H(+)-adenosinetriphosphatase (ATPase) in macrophages, which contain an inducible form of NOS. The vacuolar H(+)-ATPase is involved in proton secretion in intercalated cells in the collecting duct. We have therefore examined the effect of NO on bafilomycin-sensitive H(+)-ATPase activity in individual cortical collecting ducts (CCD) microdissected from collagenase-treated kidneys of normal rats using a fluorometric microassay. Incubation of CCD with the NO donors, sodium nitroprusside (0.1 and 1 mM) or 3-morpholino-sydnonimine hydrochloride (SIN-1, 30 microM), caused a dose-dependent decrease in H(+)-ATPase activity. Incubation of CCD with lipopolysaccharide (LPS) and interferon-gamma, which induces NOS in macrophages, decreased H(+)-ATPase activity by 85%. This effect was prevented by simultaneous incubation with N omega-nitro-L-arginine, a competitive inhibitor of NOS, indicating that the decrease in H(+)-ATPase activity was caused by NO production. Incubation with 8-bromo-guanosine 3',5'-cyclic monophosphate (cGMP) also inhibited H(+)-ATPase activity, suggesting that NO may exert its effect in the CCD via activation of guanylyl cyclase and production of cGMP. Immunohistochemistry using antibodies to the macrophage-type NOS revealed strong labeling of intercalated cells in the CCD, confirming the presence of NOS in these cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nitric oxide inhibits bafilomycin-sensitive H(+)-ATPase activity in rat cortical collecting duct. 752 55

The extreme hyperosmotic conditions that exist in the renal inner medulla enable the urinary concentrating mechanism to function. In this study, we evaluated whether stress-related molecular chaperones are induced in response to hyperosmotic stress in mouse inner medullary collecting duct (mIMCD3) cells. Exposure of cells to medium supplemented with 100 mM NaCl for 4 or 24 h resulted in an increase in heat shock protein-72 (HSP-72) (inducible form) by Western blot. Immunocytochemistry confirmed the increase of HSP-72 and showed that hyperosmotic stress resulted in a localization of HSP-72 predominantly to the nucleoplasm that surrounds the nucleoli and to the cytoplasm, a subcellular distribution pattern different from that seen with heat shock. Using a denatured protein (casein)-affinity column with ATP elution, we identified a number of putative molecular chaperones (46, 60, 78, and 200 kDa) that are upregulated in response to 4 h of hyperosmotic NaCl treatment. Microsequencing identified one of these proteins to be the mitochondrial chaperone mtHSP-70, a member of HSP-70 family, and another to be similar to beta-actin. We also found high levels of HSP-72 in cells chronically adapted to hypertonicity, indicating that chaperones are still required to maintain certain cellular functions even after nonperturbing organic osmolytes are known to accumulate. These results suggest an important role for molecular chaperones in the adaptation of renal medullary epithelial cells to the hyperosmotic conditions that exist in the inner medulla in vivo.
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PMID:Induction of molecular chaperones by hyperosmotic stress in mouse inner medullary collecting duct cells. 924 87