Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.27.5 (RNase)
17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The stimulatory and inhibitory activities in the crude preparation of protein kinase modulator from dog heart were separated by Sephadex G-100 gel filtration, and the stimulatory modulator was further purified by DEAE-cellulose chromatography. The isolated stimulatory modulator, as the crude modulator preparation, stimulated the activity of the purified guanosine 3':5'-monophosphate (cGMP)-dependent protein kinases of both mammalian and arthropod origins in the presence of cGMP. The cGMP-dependent protein kinases were not activated by cGMP in the absence of either the isolated stimulatory modulator or the crude modulator. The stimulatory modulator, unlike the crude modulator had no effect on the activity of adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase. The stimulatory modulator was a protein since its activity was destroyed by trypsin but was resistant to hydrolysis by DNase, RNase, phospholipase C, and lysozyme. The isolated inhibitory modulator, presumably the same as the protein inhibitor of cAMP-dependent protein kinase reported by Walsh et al. (Wash. D.A., Ashby, C.D., Gonzalez, C., Calkins, D., Fischer. E.H., and Krebs, E.G. (1971) J. Biol. Chem. 246, 1977-1985), depressed the cAMP-stimulated activity of cAMP-dependent protein kinase as did the crude preparation of protein kinase modulator. The isolated inhibitory modulator, unlike the crude preparation, was without effect on cGMP-dependent protein kinase. The present findings provide evidence to support that in mammals there are separate proteins for the stimulatory and the inhibitory activities of protein kinase modulator, in contrast to the modulator from an arthropod tissue (lobster tail muscle, Donnelly et al. (Donnelly, T.E., Jr., Kuo, J.F., Reyes, P.L., Liu, Y.P., and Greengard, P. (1973) J. Biol. Chem. 248, 190-198) which has been shown to possess both activities.
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PMID:Isolation of stimulatory modulator of guanosine 3':5'-monophosphate-dependent protein kinase from mammalian heart devoid of inhibitory modulator of adenosine 3':5'-monophosphate-dependent protein kinase. 18 22

The purpose of this study was to determine how RI alpha, the R subunit of the type I cAMP-dependent protein kinase, is regulated in rabbit ovarian follicles in response to the preovulatory luteinizing hormone surge. When soluble extracts from rabbit preovulatory follicles and 7-day-old corpora lutea were photoaffinity-labeled with 8-N3-[32P]cAMP, 3-fold more RI alpha was detected in corpora lutea than in follicles. Based on DEAE-cellulose chromatography, both type I holoenzyme and free RI alpha increased during luteinization. Western blot analysis of soluble extracts obtained from follicles and corpora lutea at various time points after human chorionic gonadotropin (hCG) injection revealed a 6-10-fold increase in RI alpha protein by 5 h after hCG injection. However, based on Northern blot analysis and solution hybridization/RNase protection assays, this increase in RI alpha protein was not due to an increase in RI alpha mRNA. These results suggested that RI alpha subunit levels were post-transcriptionally regulated. Half-life determinations indicated a 2.1-fold increase in the stability of RI alpha when follicles were incubated in the presence of hCG. The effect of hCG on the stability of RI alpha could also be mimicked by forskolin, thus suggesting that a rise in cAMP levels in follicles during the luteinizing hormone surge plays a role in RI alpha subunit stability. We conclude that RI alpha protein is stabilized in follicles by hCG treatment and the consequent rise in follicular cAMP levels.
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PMID:Luteinization-associated changes in protein stability of the regulatory subunit of the type I cAMP-dependent protein kinase. 132 Nov 43

Casein kinase II purified from nuclei of Xenopus laevis oocytes is inhibited by several specific nucleic acids. This kinase, the main phosphorylating activity of the oocyte nucleus, is markedly inhibited by poly U at 10 micrograms/ml, and this polymer is a competitive inhibitor of the phosphorylation of the substrate casein (Kiapp 80 nM). M 13 phage ssDNA and unfractionated yeast tRNA also inhibit between 50 and 200 micrograms/ml. Poly C, poly A, poly AG, dsDNA and Escherichia coli rRNA do not alter activity significantly at similar concentrations. Inhibitions are reversed by RNase (poly U, tRNA) or S1 nuclease (ssDNA). Oocyte casein kinase I or rabbit cAMP-dependent protein kinase are not inhibited by poly U at 200 micrograms/ml. The sensitivity of the casein kinase II to these inhibitors suggests a regulatory role for nucleic acids in nuclear phosphorylation reactions.
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PMID:Nucleic acids can regulate the activity of casein kinase II. 279 84

Several Chinese hamster ovary (CHO) cell mutants with altered cAMP-dependent protein kinases were utilized to study the possible involvement of this enzyme in mediating interferon effects in cultured cells. Human fibroblast interferon had a pronounced protective effect for CHO cells against encephalomyocarditis virus (EMCV). This protective effect was also observed in cAMP-resistant CHO mutants with protein kinase defects, although to a slightly lesser extent. EMCV, however, which grows well in wild-type CHO cells, grew poorly in the cAMP-resistant CHO mutants even in the absence of interferon, suggesting that cAMP-dependent protein kinase is involved in the normal growth of this virus. The growth inhibitory and morphological effects of human fibroblast interferon on CHO cells as well as the induction of 2',5'-oligoA synthetase and the level of RNase F activity (which is constitutive in CHO cells) were very similar in wild-type and mutant CHO cells. It is concluded from these studies that cAMP-dependent protein kinase may have a facilitating role in antiviral activity of interferon, but does not have an obligatory role in mediating either the antiviral or antiproliferative effects of interferon in CHO cells.
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PMID:Genetic evidence that action of cAMP-dependent protein kinase is not an obligatory step for antiviral and antiproliferative effects of human interferon in Chinese hamster ovary cells. 631 Aug 82

Many neurotransmitters are known to regulate neuronal cell function by means of activation of cAMP-dependent protein kinase (PKA) and phosphorylation of neuronal substrate proteins, including transcription factors and ion channels. Here, we have characterized the gene expression of two isoforms of a protein kinase inhibitor (PKI) specific for PKA in mouse brain by RNase protection and in situ hybridization histochemistry. The studies demonstrate that the PKI alpha isoform is abundant in many regions of the adult mouse brain but particularly in cerebellum, hypothalamus, hippocampus, and cortex. In contrast, PKI beta is present at much lower levels in most brain regions but is found in significant amounts in the cerebellum, as well as in distinct nuclei within the pons, medulla, and hypothalamus. These results are consistent with a regulatory role of endogenous PKI in PKA-mediated signal transduction in brain and suggest differential functions for the two isoforms of PKI within the central nervous system.
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PMID:Differential expression of mRNAs for protein kinase inhibitor isoforms in mouse brain. 787 50

The effects of glucagon on serine: pyruvate/alanine: glyoxylate aminotransferase (SPT/AGT) gene expression were studied in primary cultured rat hepatocytes. When hepatocytes had been precultured for 16-18 h under serum- and hormone-free conditions, the addition of glucagon caused (after a lag period of about 2 h) a remarkable increase in the cellular level of SPT/AGT mRNA by 4 h in a time- and dose-dependent manner. The induced mRNA was that for mitochondrial SPT/AGT, as judged by ribonuclease protection analysis. A nuclear run-on assay revealed that activation of transcription is responsible for the increase in mitochondrial SPT/AGT mRNA and that the maximal rate of transcription occurs 1.5 h after glucagon addition. The effect of glucagon was mimicked by 8-bromo-cAMP and suppressed by N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide, an inhibitor of cAMP-dependent protein kinase (protein kinase A), while both 12-O-tetradecanoylphorbol-13-acetate and A23187 were without effect in elevating the SPT/AGT mRNA level, suggesting that the cAMP/protein kinase A system is involved in the regulation of SPT/AGT gene expression. In hepatocytes precultured for 16-18 h under serum- and hormone-free conditions, the glucagon-induced transcription was severely inhibited by cycloheximide. When the preculture was for 2 h, on the other hand, the activation of transcription by glucagon was more rapid, and the inhibition by cycloheximide was less than that observed with cells precultured for 16-18 h, suggesting that a short-lived protein factor is involved in the hormonal regulation. The glucagon-induced expression of the SPT/AGT gene was also turned off by dexamethasone.
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PMID:Regulation by glucagon of serine: pyruvate/alanine: glyoxylate aminotransferase gene expression in cultured rat hepatocytes. 813 20

Ca2+/calmodulin-dependent protein kinase I (CaM kinase I) was previously purified from bovine brain (Nairn, A. C., and Greengard, P. (1987) J. Biol. Chem. 262, 7273-7281) based on its ability to phosphorylate the synaptic vesicle protein, synapsin I at site 1. The cDNA for this protein kinase has now been cloned from both a rat and a bovine brain cDNA library and the complete amino acid sequence of rat CaM kinase I determined. The rat cDNA encoded a protein of 331 amino acids with a calculated M(r) of 37,545, and the encoded kinase was expressed in bacteria as a glutathione S-transferase fusion protein. The resulting fusion protein was purified by Sepharose-CaM affinity chromatography and shown to be totally dependent on Ca2+ and CaM for activity. Furthermore, the purified kinase phosphorylates synapsin I at the same site (site 1) as the endogenous brain enzyme. CaM kinase I is homologous to other known protein kinases and contains all nine invariant amino acids conserved in the catalytic domain of this class of enzymes. CaM kinase I was most identical to CaM kinase II both in the catalytic domain and in a short region at the COOH-terminal that is predicted to be the calmodulin-binding domain. CaM kinase I appeared to be encoded by a single gene. RNase protection assays detected the mRNA encoding CaM kinase I in all tissues examined. High concentrations of the kinase mRNA were found in all regions of the brain with frontal cortex showing the greatest level. CaM kinase I was autophosphorylated in a Ca2+/CaM-dependent manner at a threonyl residue (Thr-177) which is located at a position equivalent to that of the threonyl residue (Thr-197) autophosphorylated in cAMP-dependent protein kinase.
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PMID:Calcium/calmodulin-dependent protein kinase I. cDNA cloning and identification of autophosphorylation site. 825 80

Follistatin was originally identified as a specific inhibitor of follicle stimulating hormone secretion and later characterized as a binding protein for activin. Since activin regulates hormone secretion and cell differentiation, the importance of understanding the mechanisms regulating the synthesis of its binding protein, follistatin, is evident. To study the regulation of follistatin gene expression, we first determined the transcription start site (cap site) of the rat follistatin gene using primer extension and ribonuclease protection assay. Our results led to the identification of multiple cap sites located at three different positions of the promoter. DNA sequence analysis revealed that each cap site was located at approximately 30 nucleotide (nt) downstream of three distinct TATA-like sequences. In primary cultures of rat granulosa cells, transfection studies using 5'-flanking regions of follistatin gene fused to the chloramphenicol acetyltransferase (CAT) reporter gene revealed the presence of two DNA segments that act to suppress basal transcriptional activity. The promoter activity of the CAT construct containing 2.6 kilo base pairs (kb) of 5'-flanking region was induced 2.5-fold above basal activity by forskolin (10 microM), and 1.6-fold by 12-O-tetradecanoylphorbol 13-acetate (TPA, 100 nM). Co-treatment with forskolin and TPA resulted in a 6.4-fold induction in its promoter activity, suggesting that two distinct signal transduction pathways, the cAMP-dependent protein kinase-A pathway and diacylglycerol-dependent protein kinase-C pathway, act coordinately to modulate follistatin gene transcription. Experiments using a series of 5'-flanking region deletion constructs located the regulatory regions responsive to these two pharmacological agents at nt -312 to -32 and -35 to +139.
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PMID:Structural and functional characterization of the rat follistatin (activin-binding protein) gene promoter. 847 73

The nuclear gene NUC1 encodes the major mitochondrial (mt) ribonuclease in the yeast Saccharomyces cerevisiae. We describe an in vitro mt transcription assay system based on lysates of purified mitochondria from a petite (rho-, mt deletion mutant) yeast strain in which NUC1 has been insertionally inactivated. Control in vitro run-on transcription assays using intact mitochondria demonstrate that the rate of incorporation of labeled precursor into mt RNA is identical in organelles from the nuc1 rho- mutant and its otherwise isochromosomal NUC1 parent strain. Brij-35 lysates of mitochondria from the nuc1 strain incorporate precursor into mt RNA at nearly the same rate as do intact organelles from that strain, while similar mt lysates from NUC1 cells show no such incorporation. Other control studies show that mt lysates from the nuc1 strain retain functional mt cAMP-dependent protein kinase and other critical activities. When the cloned template DNA encoding the yeast mt 21S rRNA gene, which is not retained in the nuc1 rho- strain, is added to mt lysates from that strain, transcripts are produced from the template under standard assay conditions.
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PMID:An in vitro transcription assay for yeast mitochondria using organellar lysates. 895 60

Genomic sequences flanking the 5' end of the cDNA encoding isoform C beta 2 of the catalytic subunit of bovine cAMP-dependent protein kinase were cloned, sequenced and analyzed for promoter activity and transcription initiation sites. A region of 913 bp upstream the translation initiator ATG was amplified from genomic DNA by vectorette polymerase chain reaction. In primer extension reactions and RNase protection assays, residues C (at position -91), T (-71) and G (-70) were found to serve as transcription initiation sites of the gene. Amplification products and sub-fragments thereof were ligated upstream of the reporter gene chloramphenicol acetyltransferase to test for promoter activity. Constructs were transiently transfected into a Chinese hamster ovary cell line which was shown to express endogenous C beta 2 mRNA. The genomic sequence upstream the C beta 2 cDNA does have promoter activity. The region from position -51 to -292 proved sufficient to drive efficient transcription of the reporter gene. The promoter is AT rich (68%), does not contain a TATA box within 50 bp upstream of the first initiation site and possesses putative binding sites for several transcription factors such as PEA-3 and a glucocorticoid receptor.
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PMID:Promoter of the gene encoding the bovine catalytic subunit of cAMP-dependent protein kinase isoform C beta 2. 898 58


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