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:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primary cultures of adult rat liver parenchymal cells, isolated by the collagenase perfusion technique and maintained as a monolayer, were used to investigate the characteristics of hepatic cadmium accumulation and metabolism. Cadmium accumulation was found to be a temperature- and concentration-dependent process that required sulfhydryl groups and was significantly stimulated by the addition of dexamethasone to the medium. Once taken up, cadmium was less available for exit-exchange processes than its biologically required congener, zinc. Moreover, cadmium influx enhanced zinc efflux. While most of the intracellular cadmium was located in the cytosol, its distribution within this fraction was altered with time. Initially the metal was bound to both high molecular weight species (less than 50 000) and metallothionein. As the incubation period increased, the cytosol concentration of cadmium and the percentage of this metal associated with metallothionein was likewise increased. [3H]Amino acid incorporation studies indicated that the accumulation of cadmium resulted in de novo synthesis of the 1 and 2 forms of metallothionein.
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PMID:Cadmium accumulation and metabolism by rat liver parenchymal cells in primary monolayer culture. 42 Aug 70

Adult rat liver parenchymal cells were isolated by the collagenase perfusion technique and cultured as a monolayer for up to 20 h. The quantity of zinc accumulated from the extracellular environment was significantly increased by adding physiological concentrations of certain glucocorticosteroids to the medium. The degree of stimulation was directly related to glucocorticoid potency. Sex steroids, certain peptide hormones and prostaglandins E2 and F2alpha did not influence zinc accumulation. Control cells exhibited a decline of zinc accumulation after 4 h in culture although uptake processes were still operative. When dexamethasone, the most potent glucocorticoid used, was present in the medium the cells accumulated zinc at a linear rate greater than that seen in control cells, for at least 20 h. The dexamethasone-induced stimulation of zinc accumulation was relatively specific since 45Ca, 14C-labelled amino acids and [35S]cystine accumulation was not influenced by the hormone. A lag of 4 h was observed before an effect of dexamethasone on zinc accumulation could be detected. Moreover, the hormone-stimulated phase of accumulation was blocked when the cells were simultaneously incubated with either actinomycin D or cycloheximide. The additional complement of zinc accumulated by the dexamethasone-treated cells was localized in the cytosol fraction. Gel filtration and ion-exchange chromatography confirmed that this additional cytosol zinc was bound to metallothionein. [35S]Cystine was incorporated into metallothionein in hormone-treated cells indicating that the protein was synthesized de novo during periods of enhanced zinc accumulation.
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PMID:Zinc accumulation and metabolism in primary cultures of adult rat liver cells. Regulation by glucocorticoids. 70 88

Tissue ablation by ultraviolet excimer lasers results in exposure of viable cells to subablative doses of radiation. To understand the potential biological consequences better, we have studied changes in gene expression in cultured human skin fibroblasts exposed to either 193- or 248-nm laser light. Northern blot analyses revealed that both treatments up-regulate a common set of genes, including interstitial collagenase, tissue inhibitor of metalloprotease, metallothionein, and the proto-oncogene c-fos. Dose-response and kinetic studies of collagenase induction by 193-nm radiation showed a maximal effect with 60 J/m2 and at approximately 24 h. The induction was still persistent 96 h later. In addition to the commonly affected genes, known to be activated also by conventional UV light (254 nm) and tumor-promoting phorbol esters, other genes were found to be selectively induced by the 193-nm radiation. The heat-shock hsp70 mRNA, undetectable in controls and in cultures irradiated at 248 nm, was transiently induced 8 h after exposure to 193-nm radiation. Furthermore, a selective up-regulation of collagen type I expression was observed. The results indicate that the 193- and 248-nm radiations by excimer lasers elicit specific and different cellular responses, in addition to an overlapping pathway of gene activation common also to UV radiation by germicidal lamps. The laser-induced genes could serve as molecular markers in evaluating cell injury in situ.
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PMID:Changes in gene expression by 193- and 248-nm excimer laser radiation in cultured human fibroblasts. 133 10

Normal and osteoarthritic (OA) human articular cartilage chondrocytes, released enzymatically in the presence of 0.5% fetal calf serum, display constitutive expression of early response activating protein (AP-1) genes; c-fos, c-jun and jun-B. Among the late AP-1 responsive genes, total metallothionein (MT) and stromelysin mRNAs were expressed at high levels in both normal and OA chondrocytes, while collagenase and hMT-IIA mRNA levels were elevated only in OA individuals. Despite the common AP-1 sequences present in their promoter regions, the three late genes were differentially expressed.
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PMID:Expression of c-fos, c-jun, jun-B, metallothionein and metalloproteinase genes in human chondrocyte. 163 72

Renin gene expression in the mouse kidney and submandibular gland (SMG) are differentially regulated by cAMP. In this study, we examined the potential molecular mechanism responsible for this tissue-specific regulation. 32P end-labeled synthetic oligonucleotide containing mouse renin cAMP-responsive element (CRE) was incubated with kidney nuclear extracts from either control or cAMP-treated mice and analyzed by gel mobility shift assay. Our results demonstrated that cAMP induced a nuclear protein which complexed with the CRE oligonucleotide in a specific manner. This nuclear protein-DNA binding was competed effectively by the oligonucleotide containing human chorionic gonadotropin alpha-subunit CRE but not by the mouse renin DNA fragment from which the CRE was deleted by site-directed mutagenesis. In contrast, no DNA-protein complex formation could be detected when this [32P]CRE oligonucleotide was incubated with the SMG nuclear extract from control or cAMP-treated mice. However, CRE-binding protein complex formation was demonstrated in the SMG nuclear extract when the incubation was performed in the presence of 0.8% sodium deoxycholate and 1.2% Nonidet P-40, detergents that dissociate protein-protein complexes. Furthermore, in the absence of deoxycholate, we observed that SMG nuclear extract attenuated the binding of the kidney CRE-binding protein to mouse renin CRE in a dose-dependent manner and this inhibitory effect of SMG nuclear extract disappeared in the presence of sodium deoxycholate. This inhibitory nuclear protein in SMG is specific for CRE-binding protein since it does not affect nuclear protein binding to synthetic DNA oligonucleotides of human collagenase AP-1 and human metallothionein AP-2. Our data further suggest that inhibitory nuclear protein is present in lower quantities in other extrarenal tissues, i.e. testes, liver, brain, heart, but is not detectable in the kidney. Taken together, these results suggest that the SMG and certain extrarenal tissues contain nuclear trans-acting factor(s) that interact with CRE-binding protein, thereby interfering with its binding to mouse renin CRE. The presence of this inhibitory protein in the mouse SMG nucleus may contribute to the tissue-specific regulation of the renin gene expression by cAMP.
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PMID:Molecular mechanism of tissue-specific regulation of mouse renin gene expression by cAMP. Identification of an inhibitory protein that binds nuclear transcriptional factor. 165 39

We have established mutant SaOS-2 cell lines that express a cyclic AMP (cAMP)-resistant phenotype to investigate the regulation and functional importance of orthophosphoric-monoester phosphohydrolase alkaline optimum (ALPase) in the action of parathyroid hormone (PTH). Cells were stably transfected with a plasmid that directs the synthesis of a mutant form of the type I regulatory subunit of protein kinase A (PKA) under the control of the metallothionein promotor. There was no significant difference between parental SaOS-2 cells and the mutant lines in the affinity or number of receptors for 125I-Nle8,18Tyr34bPTH1-34NH2, either in the absence or presence of Zn2+. When cAMP-dependent gene transcription was examined using transient transfection with a somatostatin promoter-chloramphenicol acetyl transferase (CAT) reporter plasmid, CAT activity stimulated by human PTH and dibutyryl cAMP (DBcAMP) was inhibited by greater than 90% in the presence of Zn2+ in the mutant cell lines. In contrast, activation by a phorbol ester of a pentameric collagenase promoter/CAT construct containing five tandem copies of the AP-1 response element (5x-TRE-CAT) was unaffected in Zn(2+)-treated mutant cells. The inhibitory actions of PTH and DBcAMP on ALPase release were blunted by up to 80-90% in the mutant cell lines in the presence of Zn2+; there were no significant differences in the magnitude of inhibitory effects between these agonists. We conclude that the inhibitory action of PTH on ALPase release in SaOS-2 cells is mediated via activation of PKA. These cAMP-resistant cell lines will be especially useful in elucidating signal transduction mechanism(s) for PTH in human osteoblastic cells.
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PMID:Protein kinase A-dependent inhibition of alkaline phosphatase release by SaOS-2 human osteoblastic cells: studies in new mutant cell lines that express a cyclic AMP-resistant phenotype. 166 91

A chimeric gene composed of the mouse metallothionein promoter linked to the 5' end of the 9.1-kilobase pair rabbit procollagenase (matrix metalloproteinase-1) gene was stably transfected into baby hamster kidney (BHK) cells. Like the native protein, the recombinant procollagenase synthesized and secreted by these cells was the product of a 2.1-kilobase pair transcript which was translated into a procollagenase protein of 57 kDa, with a small amount of protein that co-migrated with the glycosylated form of the native protein at 61 kDa. The BHK cells expressed levels of recombinant procollagenase equal to or exceeding those of rabbit synovial fibroblasts stimulated with phorbol myristate acetate, where procollagenase mRNA may comprise 2% of the mRNA population. Although minimal (approximately 10%) collagenolysis was seen when the zymogen was activated with trypsin or an organ-omercurial compound, the expression of full collagenolytic activity of the recombinant protein depended on the presence of stromelysin (matrix metalloproteinase-3). Purified recombinant collagenase displayed a specific activity of 8,400 units/mg of enzyme (1 unit degraded 1 microgram of collagen/minute at 37 degrees C) when fully activated, which was accomplished by the specific cleavage of the Gln80-Phe81 bond of procollagenase by stromelysin. We conclude that 1) these stably transfected BHK cells represent a high yield source of recombinant mammalian procollagenase, 2) activation of procollagenase depends on the presence of stromelysin, and 3) recombinant procollagenase from this high yield source may be useful in future studies to elucidate the detailed mechanism(s) involved in the activation of this enzyme.
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PMID:Rabbit procollagenase synthesized and secreted by a high-yield mammalian expression vector requires stromelysin (matrix metalloproteinase-3) for maximal activation. 217 11

Analysis of the transforming growth factor alpha (TGF alpha) cDNA predicts that the mature TGF alpha polypeptide is cleaved from the extracellular domain of its precursor, which is an integral membrane protein. Furthermore, the cleavage sites for the release of this mitogen are compatible with the participation of an elastaselike protease. We have immunohistochemically localized TGF alpha to the vascular smooth muscle cells in the arterioles. To investigate whether polymorphonuclear (PMN) leukocytic elastase, a blood-borne protease, could process the cell surface TGF alpha, NR6 cells were transfected with the rat TGF alpha cDNA. The cDNA encoded the entire open reading frame, and its expression was under the control of the mouse metallothionein I promoter. A cloned transfectant, termed 1B2, synthesized the TGF alpha precursor in a zinc-inducible manner, and the precursor was localized to the cell surface. Western blot (immunoblot) analysis indicated that treatment of the zinc-induced 1B2 cells with either PMN leukocytic or pancreatic elastase resulted in the release of the mature TGF alpha polypeptide. The released TGF alpha was bioactive, as it was capable of both competing with epidermal growth factor for binding to its receptor and stimulating [3H]thymidine incorporation in the mitogenic assay. Formaldehyde fixation of the 1B2 cells eliminated basal release of TGF alpha but allowed normal processing by both PMN leukocytic and pancreatic elastase to occur. However, human cathepsin G, bovine pancreatic alpha 1-chymotrypsin, collagenase, trypsin, subtilisin, and plasmin failed to release any detectable fragments of the TGF alpha precursor from the fixed cells. The location of TGF alpha in the arterioles and ability of PMN leukocytic elastase to process the membrane-bound TGF alpha precursor suggests a novel role for this elastase at the wound site.
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PMID:Transforming growth factor alpha in arterioles: cell surface processing of its precursor by elastases. 220 95

Femurs from 9-day-old embryo were cultured for 4 days by the roller-tube method in the presence of Cd and/or Cu. The combination of both Cd and Cu caused a significantly interactive decrease in hydroxyproline (Hyp) synthesis as well as bone growth compared with that in the presence of Cd (1.1 or 3.3 microM) or Cu (1.1 or 2.2 microM) alone. The presence of both 2.2 microM Cd and 3.3 microM Cu also showed a significantly interactive decrease in the incorporation of [3H]proline (Pro) into collagenase-digestible protein (CDP), but it showed no interactive inhibition of the hydroxylation of [3H]Pro in CDP. The two metals were also interactive with respect to the inhibition of the synthesis of protein, RNA and DNA. Culture of epiphysis in the presence of both Cd and Cu resulted in higher content of Cd and Cu compared to those cultured in Cd or Cu alone. Subcellular fractions from epiphysis cultured in Cd plus Cu contained more Cd than those cultured in Cd alone. Cu was increased in two fractions, nuclei and cytosol, following co-incubation. The cytosol from epiphysis cultured in the presence of both Cd and Cu contained more Cd in both a metallothionein (MT)-like protein and a high-molecular-weight (HM) protein than cytosol from Cd-treated bones. The amount (nmol) of Cu in the MT fraction was nearly equal to the sum of the increased amounts (nmol) of Cd in HM fraction of cytosol and particulate fractions. This indicates that some Cd in MT-like protein induced by Cd is replaced with Cu and the released Cd redistribution to HM fraction and particulate fractions. Most of the Cd in the solubilized particulate fractions was detected in the HM fraction. A marker enzyme or component in each fraction was interactively inhibited by both Cd and Cu. Therefore, the interactive inhibition of bone metabolism by both Cd and Cu in the cultured bone is at least partly due to the increase in Cd content of HM fraction of cytosol and particulate fractions.
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PMID:A possible mechanism of cadmium-copper interaction in embryonic chick bone in tissue culture. 243 15

The enhancer-binding protein AP-1 has been purified to greater than 95% homogeneity from HeLa cells by sequence-specific DNA affinity chromatography and identified as a 47 kd polypeptide. Purified AP-1 activates transcription in vitro of the wild-type human metallothionein IIA (hMT IIA) gene but not mutant hMT IIA promoters lacking AP-1 recognition sites. DNAase I protection analysis indicates that genetically defined enhancer elements in hMT IIA, SV40, and the human collagenase gene contain high-affinity AP-1-binding sites, each with a conserved recognition motif, TGACTCA. These three genes are transcriptionally induced by treatment of cells with the tumor promoter TPA. Here we demonstrate that multiple synthetic copies of the consensus AP-1-binding site can act as TPA-inducible enhancers in various plasmid constructs after transfection into HeLa cells. These findings suggest that AP-1 is a transcription factor that functions by interacting with a specific enhancer element, and that its activities may be modulated by treatment of cells with TPA, known to stimulate protein kinase C.
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PMID:Purified transcription factor AP-1 interacts with TPA-inducible enhancer elements. 303 33


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