Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

ATP consumption by arginyl-tRNA synthetases from Escherichia coli and Bacillus stearothermophilus has been investigated by the firefly luciferin--luciferase assay. Arginyl-tRNA synthetase from E. coli utilizes ATP only for aminocylation of tRNA with a 1:1 stoicheiometry. In contrast, we have shown an adenosine triphosphatase activity of arginyl-tRNA synthetase from B. stearothermophilus in the absence of tRNAArg. Dowex chromatography revealed the formation of ADP by the thermophile enzyme; under aminoacylation conditions, AMP was also formed in amounts stoicheiometric with arginyl-tRNA formation.
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PMID:Adenosine triphosphate consumption by bacterial arginyl-transfer ribonucleic acid synthetases. 38 95

Molecular chaperone complexes containing heat shock protein (Hsp) 70 and Hsp90 are regulated by cochaperones, including a subclass of regulators, such as Hsp70 interacting protein (Hip), C-terminus of Hsp70 interacting protein (CHIP), and Hsp70-Hsp90 organizing factor (Hop), that contain tetratricopeptide repeats (TPRs), where Hsp70 refers to Hsp70 and its nearly identical constitutive counterpart, Hsc70, together. These proteins interact with the Hsp70 to regulate adenosine triphosphatase (ATPase) and folding activities or to generate the chaperone complex. Here we provide evidence that small glutamine-rich protein/viral protein U-binding protein (SGT/UBP) is a cochaperone that negatively regulates Hsp70. By "Far-Western" and pull-down assays, SGT/UBP was shown to interact directly with Hsp70 and weakly with Hsp90. The interaction of SGT/UBP with both these protein chaperones was mapped to 3 TPRs in SGT/UBP (amino acids 95-195) that are flanked by charged residues. Moreover, SGT/UBP caused an approximately 30% reduction in both the intrinsic ATPase activity of Hsc70 and the ability of Hsc70 to refold denatured luciferase in vitro. This negative effect of SGT/UBP on Hsc70 is similar in magnitude to that observed for the cochaperone CHIP. A role for SGT/UBP in protein folding is also supported by evidence that a yeast strain containing a deletion in the yeast homolog to SGT/UBP (delta SGT/UBP) displays a 50-fold reduction in recovery from heat shock compared with the wild type parent. Together, these results are consistent with a regulatory role for SGT/UBP in the chaperone complex.
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PMID:Small glutamine-rich protein/viral protein U-binding protein is a novel cochaperone that affects heat shock protein 70 activity. 1248 2

Fructooligosaccharides (FOS) are indigestible oligosaccharides that increase calcium absorption by the colorectum in rats, but the underlying mechanisms remain unclear. We therefore investigated the effects of FOS on expressions of genes involved with calcium absorption in rat colorectal mucosa cells. After feeding a diet containing FOS (100 g/kg diet) to rats for 2 d, we investigated gene transcripts of transient receptor potential vanilloid type 6 (TRPV6), calbindin-D9k, and plasma membrane calcium-ATPase 1b (PMCA1b). The FOS diet increased expression of TRPV6 and calbindin-D9k but did not affect PMCA1b expression. Because FOS could not directly affect gene expression, SCFA formed as fermentation products of FOS were considered as likely intermediates. SCFA (2.0 mmol/L) were thus added to Caco-2 human colonic epithelial cells, resulting in significantly increased mRNA expression of TRPV6. To ascertain the effects of SCFA on mRNA expression, a genomic clone of TRPV6 was isolated. Using luciferase reporter assay, a segment between -71 nucleotides and the translation start site was found to contain a positive responsive element to SCFA. These results suggest that FOS increase calcium absorption by increasing mRNA expression of TRPV6 in rat colorectum, and cell culture analysis indicated that SCFA, as fermentation products of FOS, are involved in the increased mRNA expression of TRPV6. We found for the first time, to our knowledge, that regulation of TRPV6 gene expression by SCFA may be a molecular mechanism involved in the promotion of calcium absorption by FOS in rats.
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PMID:Short-chain fatty acids induce intestinal transient receptor potential vanilloid type 6 expression in rats and Caco-2 cells. 1905 62

Streptococcus intermedius DnaK complements the temperature-sensitive phenotype of an Escherichia coli dnaK null mutant only when co-chaperones DnaJ and GrpE are co-expressed. Therefore, whether S. intermedius DnaK and E. coli DnaK can recognize heterologous co-chaperones in vitro was examined. Addition of heterologous GrpE to DnaK and DnaJ partially stimulated adenosine triphosphatase (ATPase) activity, and almost completely stimulated luciferase refolding activity. Addition of heterologous DnaJ to GrpE and DnaK also stimulated ATPase activity; however, significant luciferase refolding activity was not observed. Moreover, E. coli DnaJ had a negative effect on the luciferase refolding activity of the S. intermedius DnaK chaperone system. In E. coli chaperone mutants, with the exception of E. coli DnaJ, stronger expression of the heterologous co-chaperones partially or almost completely complemented the temperature-sensitive-phenotype. These results indicate that all heterologous co-chaperones can at least partially recognize DnaK of a distantly related species. A region of the ATPase domain that is present in the DnaK of gram-negative bacteria is absent from the DnaK of gram-positive bacteria. This region is believed to be important for recognition of co-chaperones from gram-negative bacteria. However, insertion of this segment into S. intermedius DnaK failed to increase its ability to recognize E. coli co-chaperones, implying that this region is unnecessary or insufficient for the recognition of E. coli co-chaperones. Thus, our data suggest that a basic structural similarity is conserved among the components of the S. intermedius and E. coli DnaK chaperone systems, allowing weak associations between heterologous components.
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PMID:Recognizability of heterologous co-chaperones with Streptococcus intermedius DnaK and Escherichia coli DnaK. 3023 35