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)

Inducible HSP70s encoded by two almost identical hsp70 genes, known as hsp70.1 and hsp70.3 are located in a tandem array on mouse chromosome 17. Duplication of this gene has been found in various higher organisms. However, the role of two almost identical hsp70 genes is still unclear. To elucidate the ambiguity of expression pattern between hsp70.1 and hsp70.3, we investigated the induction of each hsp70 isoforms by several HSP70-inducible stressors in wild type (hsp70.1+/+ and hsp70.3+/+) and the hsp70.1-/- (hsp70.1-/- and hsp70.3+/+) murine embryo fibroblast (MEF) cells, and the M-1 mouse cortical collecting duct cell line. Each induced hsp70 isoforms by heat shock were very similar at transcriptional and translational levels in wild type and hsp70.1-/- MEF cells. The mRNA stabilities of both hsp70.1 and hsp70.3, even in two kinds of hsp70.3 transcripts, were also very similar. L-azetidine-2-carboxylic acid, sodium arsenite, CdCl2 and ZnCI2 caused induction of both isoforms of the hsp70 genes, even though their expression levels were variable. NaCl caused induction of just hsp70.1 gene expression. H2O2 failed to induce the expression of either hsp70 genes in MEF cells, caused induction of hsp70.1 gene expression in the M-1 cell line. Hsp70 accumulation by H2O2 and NaCl treatment was mainly due to hsp70.1 expression. Our studies demonstrated that two hsp70 genes respond differentially to types of stress.
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PMID:Differential expression of two stress-inducible hsp70 genes by various stressors. 1208 88

Intracellular ionic strength may play an important role in regulating the expression of genes encoding osmolyte-accumulating molecules. To establish whether a strict relation exists between these variables, intracellular ionic strength (sum of Na+, Cl- and K+ concentrations) and the relative abundance of mRNA derived from various tonicity-sensitive genes was examined using electron microprobe analysis and Northern blots on primary cultures of rat papillary collecting duct (PCD) cells following acute or long-term alterations in medium tonicity. Hypertonic medium (450 mosmol kg(-1)) evoked an initial rise in intracellular ionic strength (269 +/- 5 vs. 194 +/- 7 mmol (kg wet weight (wt))(-1) in isotonic controls; means +/- S.E.M.), which subsequently declined gradually, and a significantly higher abundance of bgt1 (Na+- and Cl- -dependent betaine transporter), smit (Na+/myo-inositol cotransporter), ar (aldose reductase) and osp94 (osmotic stress protein 94) mRNAs. Conversely, exposure to hypotonic medium (200 mosmol kg(-1)) for 12 h was associated with significantly reduced intracellular ionic strength (153 +/- 4 mmol (kg wet wt)(-1)) and significantly reduced the abundance of smit and ar mRNAs. PCD cells preconditioned in hypotonic medium and re-exposed to isotonic medium showed significantly higher abundance of these mRNAs than isotonic controls, although the intracellular ionic strength did not differ. Two further tonicity-sensitive genes responded differently to medium tonicity: while the abundance of hsp70 (heat shock protein 70) mRNA increased significantly following both hypo- and hypertonic stress, inos (inducible nitric oxide synthase) mRNA abundance correlated inversely with medium tonicity. These findings support the view that the effect of intracellular ionic strength on the expression of bgt1, smit, ar and osp94 is modulated by additional factors such as cell volume, and that its effect on the pathways regulating hsp70 and inos is even more complex.
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PMID:Relationship between intracellular ionic strength and expression of tonicity-responsive genes in rat papillary collecting duct cells. 1218 Dec 87

Vasopressin-mediated control of water permeability in the renal collecting duct occurs in part through regulation of the distribution of aquaporin-2 (AQP2) between the apical plasma membrane and intracellular membrane compartments. Phosphorylation of Ser-256 at AQP2's cytoplasmic COOH-terminus is well-accepted as a critical step for translocation. The aim of this study was to identify binding partners to phosphorylated versus nonphosphorylated forms of the AQP2 COOH-terminus via a targeted comparative proteomic approach. Cytosol from inner medullary collecting ducts isolated from rat kidneys was incubated with "bait" peptides, representing the COOH-terminal AQP2 tail in its nonphosphorylated and phosphorylated forms, to capture differentially bound proteins prior to LC-MS/MS analysis. Mass spectrometric results were confirmed by immunoblotting. Immunoprecipitation was performed using an AQP2 COOH-terminal antibody combined with immunblotting against the proposed binding partners to demonstrate interactions with native AQP2. Our studies confirmed previously identified interactions between AQP2 and hsc70, hsp70-1 and -2, as well as annexin II. These proteins were found to bind less to the Ser-256-phosphorylated AQP2 than to the nonphosphorylated form. In contrast, another heat shock protein, hsp70-5 (BiP/grp78), bound to phosphorylated AQP2 more avidly than to nonphosphorylated AQP2. Immunogold EM studies demonstrated that BiP is present not only in the ER but also in the cytoplasm and apical plasma membrane of rat collecting duct cells. Furthermore, confocal immunofluorescence studies showed partial colocalization of BiP with AQP2 in non-ER compartments. These results suggest that phosphorylation of AQP2 at Ser-256 may regulate AQP2 trafficking in part by mediating differential binding of hsp70 family proteins to the COOH-terminal tail.
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PMID:Identification of phosphorylation-dependent binding partners of aquaporin-2 using protein mass spectrometry. 1920 2