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:3.2.1.31 (beta-glucuronidase)
7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The degranulation reactions of human neutrophils induced by 1-oleoyl-2-acetylglycerol (OAG), phorbol 12-myristate 13-acetate (PMA), and calcium ionophore A23187 or their combinations, were studied. OAG in the absence of the Ca2+-ionophore A23187 stimulated the releases of both lysozyme and lactoferrin, constituents of the specific granules, but did not stimulate the release of beta-glucuronidase, an enzyme of the azurophil granules. Electron microscopy revealed a selective decrease in the numbers of the specific granules in this case. The combined effects of A23187 at a concentration higher than 0.1 microM and OAG were essentially additive. W-7, known to be an inhibitor of both Ca2+-activated phospholipid-dependent protein kinase (C-kinase) and calmodulin, inhibited the degranulation induced by OAG or PMA, while it inhibited the reaction induced by A23187 less markedly. The release of lysozyme reached a plateau at about 0.1 microM A23187 and increased again at higher concentrations of A23187. The observations suggest that degranulation can be induced by the activation of the C-kinase, and the degranulation by A23187 at low concentrations may be due to the activation of the C-kinase; the effects of A23187 at high concentrations, however, could not be explained only in terms of the activation of the C-kinase.
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PMID:The role of Ca2+ and Ca2+-activated phospholipid-dependent protein kinase in degranulation of human neutrophils. 300 50

The interaction of cytochalasin B-treated human neutrophils with the synthetic tripeptide, N-formyl-methionyl-leucyl-phenylalanine (FMLP) results in a time- and concentration-dependent generation of superoxide anion (O2-) by an extracellular release of granule-associated beta-glucuronidase and lysozyme from these cells. Granule exocytosis was not accompanied by significant cytoplasmic lactate dehydrogenase extrusion. FMLP-stimulated O2- production occurs but is significantly curtailed in the absence of extracellular calcium. Nevertheless, incubation of neutrophils with EGTA in calcium-free medium had no effect on the O2- -generating system. Trifluoperazine (TFP), an inhibitor of calmodulin (a calcium-binding protein), caused a dose-related inhibition of FMLP-elicited degranulation and O2- production in the presence of absence of extracellular calcium. This effect TFP could be reversed by washing the cells before contact with FMLP. These data suggest that TFP represents a useful tool for defining the relevance of calmodulin and calcium to neutrophil function.
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PMID:Effects of trifluoperazine on human neutrophil function. 627 92

Hydrolysis of 3-methylumbelliferyl glucuronide by liver microsomal beta-glucuronidase is enhanced about 2-fold by micromolar concentrations of Ca2+; half-maximal stimulation occurs with 0.35 microM Ca2+. Dissociation of the enzyme from microsomal membranes by various treatments increases basal beta-glucuronidase activity and markedly decreases the sensitivity of the enzyme to Ca2+. Under similar conditions, the soluble lysosomal form of the enzyme is insensitive to Ca2+. Ca2+ stimulation was unaltered by addition of calmodulin inhibitors or exogenous calmodulin. Thus, interaction of cytosolic Ca2+ with membrane bound beta-glucuronidase may modulate glucuronidation in intact hepatocytes via a novel, calmodulin-independent mechanism.
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PMID:Stimulation of hepatic microsomal beta-glucuronidase by calcium. 674 23

1-O-Hexadecyl-2-O-acetyl-sn-glyceryl-3-phosphorylcholine (C16-AGEPC) and 1-O-octadecyl-2-O-acetyl-sn-glyceryl-3-phosphorylcholine (C18-AGEPC) stimulated a time- and concentration-dependent release of granule-associated lysozyme and beta-glucuronidase from human neutrophils. Maximum discharge of granule enzymes occurred between 30 and 60 sec after neutrophil exposure to C16- or C18-AGEPC (0.01-10 microM). Less than 10% of total enzyme activity is released when cells are not preincubated with cytochalasin B prior to interaction with the AGEPC analogs. A time-dependent desensitization for granule exocytosis was observed in neutrophils which were stimulated with C18-AGEPC prior to contact with cytochalasin B. The rate and amount of enzyme released by C16- and C18-AGEPC activated neutrophils was significantly enhanced in the presence of extracellular calcium. Trifluoperazine, an inhibitor of calmodulin, caused a dose-related suppression of C18-AGEPC-induced degranulation. Granule enzyme extrusion from C18-AGEPC-treated neutrophils was inhibited by the sulfhydryl reagents, N-ethylmaleimide and iodoacetic acid, and by the glycolytic inhibitor, 2-deoxy-D-glucose. Sodium cyanide was inactive. Pretreatment of neutrophils with C16- or C18-AGEPC rendered the cells unresponsive to subsequent exposure to either AGEPC analog. C18-AGEPC-induced desensitization of neutrophil degranulation appears to be stimulus specific in that serum-treated zymosan and N-formyl-methionyl-leucyl-phenylalanine were capable of eliciting granule enzyme release from C18-AGEPC-pretreated cells.
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PMID:Characteristics of 1-O-hexadecyl- and 1-O-octadecyl-2-O-acetyl-sn-glyceryl-3-phosphorylcholine-stimulated granule enzyme release from human neutrophils. 687 58

Eight genomic clones of potato calmodulin (PCM1 to 8) were isolated and characterized. Sequence comparisons of different genes revealed that the deduced amino acid sequence of PCM1 had several unique substitutions, especially in the fourth Ca(2+)-binding area. The expression patterns of different genes were studied by northern analysis using the 3'-untranslated regions as probes. The expression of PCM1, 5, and 8 was highest in the stolon tip and it decreased during tuber development. The expression of PCM6 did not vary much in the tissues tested, except in the leaves, where the expression was lower; whereas, the expression of PCM4 was very low in all the tissues. The expression of PCM2 and PCM3 was not detected in any of the tissues tested. Among these genes, only PCM1 showed increased expression following touch stimulation. To study the regulation of PCM1, transgenic potato plants carrying the PCM1 promoter fused to the beta-glucuronidase (GUS) reporter gene were produced. GUS expression was found to be developmentally regulated and touch-responsive, indicating a positive correlation between the expression of PCM1 and GUS mRNAs. These results suggest that the 5'-flanking region of PCM1 controls developmental and touch-induced expression. X-Gluc staining patterns revealed that GUS localization is high in meristematic tissues such as the stem apex, stolon tip, and vascular regions.
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PMID:Calmodulin gene family in potato: developmental and touch-induced expression of the mRNA encoding a novel isoform. 772 47

The Arabidopsis touch (TCH) genes are up-regulated in response to various environmental stimuli, including touch, wind, and darkness. Previously, it was determined that TCH1 encodes a calmodulin; TCH2 and TCH3 encode calmodulin-related proteins. Here, we present the sequence and genomic organization of TCH3. TCH3 is composed of three repeats; remarkably, the first two repeats share 94% sequence identity, including introns that are 99% identical. The conceptual TCH3 product is 58 to 60% identical to known Arabidopsis calmodulins; however, unlike calmodulin, which has four Ca2+ binding sites, TCH3 has six potential Ca2+ binding domains. TCH3 is capable of binding Ca2+, as demonstrated by a Ca(2+)-specific shift in electrophoretic mobility. 5' Fragments of the TCH3 locus, when fused to the beta-glucuronidase (GUS) reporter gene, are sufficient to confer inducibility of expression following stimulation of plants with touch or darkness. These TCH3 sequences also direct expression to growing regions of roots, vascular tissue, root/shoot junctions, trichomes, branch points of the shoot, and regions of siliques and flowers. The pattern of expression of the TCH3/GUS reporter genes most likely reflects expression of the native TCH3 gene, because immunostaining of the TCH3 protein shows similar localization. The tissue-specific expression of TCH3 suggests that expression may be regulated not only by externally applied mechanical stimuli but also by mechanical stresses generated during development. Consequently, TCH3 may perform a Ca(2+)-modulated function involved in generating changes in cells and/or tissues that result in greater strength or flexibility.
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PMID:Arabidopsis TCH3 encodes a novel Ca2+ binding protein and shows environmentally induced and tissue-specific regulation. 782 91

Previous work using microinjection into single cells of the tomato aurea mutant demonstrated that phytochrome A-dependent activation of rbcS and chs genes was mediated by calcium and cGMP, respectively. This work sought to identify promoter cis-elements that respond to these two small molecules. Box II and Unit I, derived from rbcS-3A and chs promoters, respectively, were previously shown to function as light-responsive cis-elements. Eleven copies of Box II and four copies of Unit I were linked 5' to the -90 and -46 35 S promoters, respectively, and, both constructs were fused to the beta-glucuronidase (GUS) reporter gene. GUS activities were obtained upon coinjection of either Box II/-90GUS or Unit I/-46GUS with oat phytochrome A (phyA) and GTP gamma S, an activator of heterotrimeric G proteins. The activation of Box II/-90GUS by phyA was insensitive to the cGMP antagonist, Rp-cGMPS, although anthocyanin accumulation, but not chloroplast development, was totally blocked in the injected cells. Consistent with this result, calcium, but not cGMP, induced Box II/-90GUS activity. In contrast to Box II/-90GUS, phyA-dependent activation of Unit I/-46GUS activity was blocked by Rp-cGMPS. Moreover, cGMP, not calcium, induced Unit I/-46GUS activity. Control experiments showed that -90 GUS and -46 GUS were inactive in the presence of calcium and cGMP, respectively. These results provide evidence that Box II and Unit I are targets of the calcium and cGMP pathways, respectively. Interestingly, calcium activation of Box II/-90GUS was repressed by a high concentration of cGMP and cGMP induction of Unit I/-46GUS was blocked by a high concentration of calcium/CaM. Thus, these two small cis-elements can also serve as targets of the reciprocal control mechanisms that operate to regulate the activities of the two phyA signaling branches.
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PMID:Calcium and cGMP target distinct phytochrome-responsive elements. 901 Oct 95

Chimeric Ca(2+)/calmodulin-dependent protein kinase (CCaMK) was cloned from developing anthers of lily (Lilium longiflorum Thumb. cv. Nellie White) and tobacco (Nicotiana tabacum L. cv. Xanthi). Previous biochemical characterization and structure/function studies had revealed that CCaMK has dual modes of regulation by Ca(2+) and Ca(2+)/calmodulin. The unique structural features of CCaMK include a catalytic domain, a calmodulin-binding domain, and a neural visinin-like Ca(2+)-binding domain. The existence of these three features in a single polypeptide distinguishes it from other kinases. Western analysis revealed that CCaMK is expressed in a stage-specific manner in developing anthers. Expression of CCaMK was first detected in pollen mother cells and continued to increase, reaching a peak around the tetrad stage of meiosis. Following microsporogenesis, CCaMK expression rapidly decreased and at later stages of microspore development, no expression was detected. A tobacco genomic clone of CCaMK was isolated and transgenic tobacco plants were produced carrying the CCaMK promoter fused to the beta-glucuronidase reporter gene. Both CCaMK mRNA and protein were detected in the pollen sac and their localizations were restricted to the pollen mother cells and tapetal cells. Consistent results showing a stage-specific expression pattern were obtained by beta-glucuronidase analysis, in-situ hybridization and immunolocalization. The stage- and tissue-specific appearance of CCaMK in anthers suggests that it could play a role in sensing transient changes in free Ca(2+) concentration in target cells, thereby controlling developmental events in the anther.
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PMID:Developmental regulation of the gene for chimeric calcium/calmodulin-dependent protein kinase in anthers. 1043 17

A promoter tagging program in the legume Lotus japonicus was initiated to identify plant genes involved in the nitrogen-fixing symbiosis between legumes and rhizobia. Seven transformed plant lines expressing the promoterless reporter gene uidA (beta-glucuronidase; GUS) specifically in roots and/or nodules were identified. Four of these expressed GUS in the roots only after inoculation with nodule-forming Mesorhizobium loti. In one line (T90), GUS activity was found in the root epidermis, including root hairs. During seedling growth, GUS expression gradually became focused in developing nodules and disappeared from root tissue. No GUS activity was detected when a non-nodulating mutant of M. loti was used to inoculate the plants. The T-DNA insertion in this plant line was located 1.3 kb upstream of a putative coding sequence with strong homology to calcium-binding proteins. Four motifs were identified, which were very similar to the "EF hands" in calmodulin-related proteins, each binding one Ca2+. We have named the gene LjCbp1 (calcium-binding protein). Northern (RNA) analyses showed that this gene is expressed specifically in roots of L. japonicus. Expression was reduced in roots inoculated with non-nodulating M. loti mutants and in progeny homozygous for the T-DNA insertion, suggesting a link between the T-DNA insertion and this gene.
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PMID:Mesorhizobium loti increases root-specific expression of a calcium-binding protein homologue identified by promoter tagging in Lotus japonicus. 1083 Feb 60

Tuberization in potato is controlled by hormonal and environmental signals. Ca(2+), an important intracellular messenger, and calmodulin (CaM), one of the primary Ca(2+) sensors, have been implicated in controlling diverse cellular processes in plants including tuberization. The regulation of cellular processes by CaM involves its interaction with other proteins. To understand the role of Ca(2+)/CaM in tuberization, we have screened an expression library prepared from developing tubers with biotinylated CaM. This screening resulted in isolation of a cDNA encoding a novel CaM-binding protein (potato calmodulin-binding protein (PCBP)). Ca(2+)-dependent binding of the cDNA-encoded protein to CaM is confirmed by (35)S-labeled CaM. The full-length cDNA is 5 kb long and encodes a protein of 1309 amino acids. The deduced amino acid sequence showed significant similarity with a hypothetical protein from another plant, Arabidopsis. However, no homologs of PCBP are found in nonplant systems, suggesting that it is likely to be specific to plants. Using truncated versions of the protein and a synthetic peptide in CaM binding assays we mapped the CaM-binding region to a 20-amino acid stretch (residues 1216-1237). The bacterially expressed protein containing the CaM-binding domain interacted with three CaM isoforms (CaM2, CaM4, and CaM6). PCBP is encoded by a single gene and is expressed differentially in the tissues tested. The expression of CaM, PCBP, and another CaM-binding protein is similar in different tissues and organs. The predicted protein contained seven putative nuclear localization signals and several strong PEST motifs. Fusion of the N-terminal region of the protein containing six of the seven nuclear localization signals to the reporter gene beta-glucuronidase targeted the reporter gene to the nucleus, suggesting a nuclear role for PCBP.
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PMID:Isolation and characterization of a novel calmodulin-binding protein from potato. 1168 78


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