Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.2.1.13 (glyceraldehyde-3-phosphate dehydrogenase)
6,511 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cellular mechanism whereby growth hormone (GH) acutely stimulates adipocyte glucose uptake was studied in cultures of primary rat adipocytes differentiated in vitro. Preadipocytes were isolated by collagenase digestion of inguinal fat-pads from young rats and were differentiated in the presence of 3-isobutyl-1-methylxanthine, insulin and dexamethasone. The development of an adipocyte morphology (i.e. lipid inclusions) was observed over 6 days after initiation of differentiation. Coincident with this phenotypic change was an increase in glyceraldehyde-3-phosphate dehydrogenase (GPDH) activity and in cellular content of the HepG2-type (Glut1) and adipocyte/muscle (Glut4) glucose transporter isoforms as determined by Western immunoblotting of total cellular protein. Age-matched undifferentiated cells expressed the Glut1 transporter and low levels of GPDH, but neither accumulated lipid nor exhibited measurable expression of the Glut4 protein. On day 6 after the initiation of differentiation, GH and insulin stimulated 2-deoxy[14C]glucose uptake in a dose- and time-dependent fashion in adipocytes cultured under serum-free conditions for at least 15 h. Western-blot analysis of subcellular fractions revealed that both GH and insulin rapidly (within 20 min) stimulated translocation of the Glut1 and Glut4 proteins from a low-density microsomal fraction to the plasma membrane. Confirmatory evidence was provided in immunocytochemical experiments utilizing antisera directed against the C-terminal region of the Glut4 protein and a fluorescein isothiocyanate-labelled second antibody. Observation of the cells via confocal laser microscopic imaging was consistent with glucose transporter redistribution from an intracellular region to the plasma membrane after treatment with GH or insulin. On the basis of these data, we suggest that the insulin-like effect of GH on adipocyte glucose transport involves translocation of the Glut1 and Glut4 proteins to the plasma membrane. Furthermore, stimulation of glucose-transporter translocation by both GH and insulin may indicate a common cell signalling element between the adipocyte GH and insulin receptors or, alternatively, the existence of multiple cellular mechanisms for stimulating glucose-transporter translocation.
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PMID:Cellular mechanism of the insulin-like effect of growth hormone in adipocytes. Rapid translocation of the HepG2-type and adipocyte/muscle glucose transporters. 137 70

Total cellular RNA was extracted from bone cells of three different femoral compartments of 2-mo-old rats. The intact femora were first incubated with collagenase to obtain periosteal cells. The bisected periosteum-free diaphyses and metaphyses were then incubated with collagenase to obtain enriched populations of endosteal and cancellous bone cells, respectively. The total cellular RNA from these three tissues was separated by size using agarose gel electrophoresis, transferred to nylon filters, hybridized to 32P-labeled cDNA probes for glyceraldehyde-3-phosphate dehydrogenase (GAP), pre-pro-alpha (I) type I collagen (collagen), osteocalcin (BGP), and alkaline phosphatase (AP), and the cDNA/mRNA hybrids were visualized by radioautography. Bone matrix deposition was measured in each tissue compartment by tetracycline-based dynamic bone histomorphometry. The bone formation and apposition rates were greatest in the periosteum and least in metaphysis. Mean mRNA levels for collagen and BGP were positively correlated with mean bone formation and mineral apposition rates. Interestingly, mean AP mRNA levels were not correlated with indexes of bone formation. These results demonstrate that the steady-state mRNA levels for bone matrix proteins in femora show pronounced site specificity and correlate with the rates of bone matrix deposition.
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PMID:Tissue-specific expression of bone proteins in femora of growing rats. 141 91

Primary and passaged human synovial fibroblasts isolated from rheumatoid pannus were treated with recombinant interleukin-1 (IL-1) alpha or beta, tumor necrosis factor-alpha (TNF), or phorbol myristate acetate (PMA) to determine the effects of these stimuli on the relative expression of stromelysin, collagenase, and tissue inhibitor of metalloproteinases (TIMP). The steady-state mRNA levels for these genes and glyceraldehyde-3-phosphate dehydrogenase were determined on Northern blots. Immunoblot analyses of the conditioned media using monoclonal antibodies generated against recombinant human stromelysin, collagenase, or TIMP showed that protein levels reflected the corresponding steady-state mRNA levels. The results revealed that 1) stromelysin and collagenase were not always coordinately expressed; 2) IL-1 was more potent than TNF or PMA in the induction of stromelysin expression; 3) neither IL-1 nor TNF significantly affected TIMP expression; 4) PMA induced both metalloproteinase and TIMP expression; and 5) the combination of IL-1 plus TNF had a synergistic effect on stromelysin expression. Dose response and time course experiments demonstrated that the synergistic effect of IL-1 plus TNF occurred at saturating concentrations of each cytokine and lasted for 7 days. In summary, the ability of IL-1 and TNF to preferentially induce stromelysin and collagenase expression, versus TIMP, may define a pivotal role for these cytokines in the pathogenesis of rheumatoid arthritis.
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PMID:Discoordinate expression of stromelysin, collagenase, and tissue inhibitor of metalloproteinases-1 in rheumatoid human synovial fibroblasts. Synergistic effects of interleukin-1 and tumor necrosis factor-alpha on stromelysin expression. 169 73

FK506, a neutral macrolide with immunosuppressive properties, was shown to selectively and rapidly inhibit the accumulation of IL-2 mRNA, as well as the mRNAs of other early (E) phase T cell activation genes such as IL-3, IL-4, GM-CSF, TNF alpha, IFN-gamma, and c-myc in activated human peripheral blood T cells. The activity of FK506, when compared to Cyclosporin A, another immunosuppressant, was 10 to 100x more potent in its ability to inhibit IL-2 mRNA synthesis. FK506 inhibited IL-2 mRNA accumulation in Con A, Con A plus PMA, Ionomycin plus PMA, anti-CD3, and anti-CD3 plus PMA activated T cells. Transcripts from other T cell gene classes such as the immediate early (IE) phase gene, c-fos, the late phase (L) genes, transferrin receptor, IL-2R alpha-chain, and TNF-beta, and the constitutive class genes glyceraldehyde-3-phosphate dehydrogenase and class I MHC HLA-B7 were not affected by FK506. The macrolide Rapamycin, which is structurally related to FK506, had no inhibitory effect on IE, E, L, or constitutive class mRNAs, but it appeared to increase the levels of the E-phase transcripts that were inhibited in FK506 treated T cells. The effect of FK506 on inducible genes in non-T and non-lymphoid human cells was studied in LPS-induced monocytes and PMA or IL-1 activated synovial fibroblasts. FK506 did not affect expression of the mRNAs for IL-1 alpha or IL-1 beta in human monocytes, or of stromelysin, collagenase, or TIMP in synovial fibroblasts. Nuclear run-off transcription studies indicate that FK506 inhibits transcription of the IL-2 gene. These studies suggest that Cyclosporin A and FK506 may effect a common early event in the T cell activation pathway.
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PMID:The immunosuppressant FK506 selectively inhibits expression of early T cell activation genes. 247 51

A method was devised for the isolation of round spermatids from the rat using a positive immunoselection technique (panning). A testis suspension was prepared from adult rats by enzymatic digestion of seminiferous tubules with collagenase. Specific mouse monoclonal antibody (97.25) was indirectly attached to Petri dishes and used in a panning protocol to purify spermatids from the testis cell suspension. The quantity and purity of cells isolated were determined by cell counts and histochemical (periodic acid-Schiff stain) or by immunostaining with acrosome-specific antibodies. A mean yield of 1.38 +/- 0.15 x 10(7) cells per dish was obtained with a purity of more than 90%. The viability of the cells was confirmed by epifluorescent microscopy with propidium iodide/carboxyfluorescein acetate probes. Northern blot analysis of RNA extracted directly from the dish indicated good integrity of a spermatid-specific transcript of glyceraldehyde-3-phosphate dehydrogenase (GAPDH).
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PMID:Separation of round spermatids from the rat using an immunoselection panning technique. 858 34

Uca pugilator serine collagenase 1 was cloned and sequenced from a fiddler crab hepatopancreas cDNA library. A full-length sequence encodes a 270-amino acid pre-pro-enzyme highly identical in structure to the chymotrypsin family of serine proteases. The zymogen form of the enzyme was expressed in Saccharomyces cerevisiae as a fusion with the alpha-factor signal sequence under control of the alcohol dehydrogenase/glyceraldehyde-3-phosphate dehydrogenase promoter. Upon activation with trypsin, the recombinant collagenase possesses collagenolytic properties identical to those of the enzyme isolated from the crab hepatopancreas. The collagenase substrate binding pocket recognizes a wide range of basic, hydrophobic, and neutral polar residues. beta-Branched and acidic amino acids are poor substrates. Acylation is rate-limiting for collagenase versus peptidyl amides, rather than deacylation, as for trypsin and chymotrypsin. Correlations relating substrate volume and hydrophobicity to catalysis were found for collagenase and compared to those for chymotrypsin and elastase. Relative enzyme efficiencies on single amino acid versus tetrapeptide amide substrates show that collagenase derives less catalytic efficiency from binding of the primary substrate residue than trypsin or chymotrypsin, but compensates in binding of the extended peptidyl residues. Serine collagenase 1 is a novel member of the chymotrypsin protease family, by virtue of its amino acid sequence and multifunctional active site.
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PMID:Substrate recognition by recombinant serine collagenase 1 from Uca pugilator. 862 18

We examined metalloproteinase (MMP)-1, -2, -3, and -9 mRNA expression by peripheral blood monocytes from 50 patients with immunoglobulin A (IgA) nephropathy, 20 with membranous nephropathy, 10 with minimal-change nephrotic syndrome, five with focal glomerulosclerosis, 30 with non-IgA proliferative glomerulonephritis, and 40 healthy normal controls who were comparable with regard to age and sex. Monocytes from patients with IgA nephropathy expressed a higher level of MMP-9 mRNA than those from patients with other forms of glomerulonephritis or from healthy controls (MMP-9 to glyceraldehyde-3-phosphate dehydrogenase ratio: IgA nephropathy, 1.68 +/- 0.24; membranous nephropathy, 0.22 +/- 0.08; minimal-change nephrotic syndrome, 0.24 +/- 0.06; focal glomerulosclerosis, 0.32 +/- 0.08; non-IgA proliferative glomerulonephritis, 0.30 +/- 0.12; and healthy controls, 0.16 +/- 0.04). When the biopsy specimens were classified into four grades according to the severity of glomerular and interstitial pathology, highly significant differences were observed among MMP-9 mRNA levels in monocytes from all four groups of patients with IgA nephropathy (grade I, 0.44 +/- 0.09; grade II, 1.06 +/- 0.26; grade III, 2.22 +/- 0.68; grade IV, 2.86 +/- 0.88). In addition, MMP-9 mRNA levels from patients with IgA nephropathy correlated with urinary protein excretion (P < 0.001). However, we detected minimal mRNA expression of MMP-1, -2, and -3 by peripheral blood monocytes from patients with IgA nephropathy or other forms of glomerulonephritis and from normal healthy controls. Our results suggest that increased MMP-9 mRNA expression in circulating monocytes may contribute to the progression of IgA nephropathy.
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PMID:Increased mRNA expression of metalloproteinase-9 in peripheral blood monocytes from patients with immunoglobulin A nephropathy. 871 19

Previous studies have shown that costochondral cartilage cell cultures produce extracellular matrix vesicles which contain metalloproteinase activity. In the present study, we examined whether two matrix metalloproteinases (MMPs) known to be present in cartilage, stromelysin-1 and 72 kDa gelatinase, are expressed by fourth passage resting zone and growth zone costochondral chondrocytes and whether they are specifically incorporated into matrix vesicles produced by the cells. We also examined whether the cells synthesize tissue inhibitor of metalloproteinase-1 and -2 (TIMP-1 and TIMP-2). Oligonucleotide primers for stromelysin-1, 72 kDa gelatinase, tissue inhibitor of metalloproteinases-1 and -2 (TIMP-1 and TIMP-2), and GAPDH were synthesized and optimized for use in the reverse transcription-polymerase chain reaction (RT-PCR). It was found that both resting zone and growth zone chondrocytes produced mRNA for both MMPs and the two TIMPs. Further, immunostaining of cell layers with antibodies to 72 kDa gelatinase and stromelysin-1 showed that both cell types produced these MMPs in culture. Substrate gel electrophoresis and Western analysis were used to characterize MMP activity in matrix vesicles, media vesicles, or plasma membranes as well as in conditioned media produced by the chondrocyte cultures. It was found that matrix vesicles but not plasma membranes or media vesicles were selectively enriched in stromelysin-1. Also, 72 kDa gelatinase was found in matrix vesicles, but to a lesser extent than seen in media vesicles. The relative activity of each enzyme detected was cell maturation-dependent. No MMP activity was detected in conditioned media produced by either cell type. The results of this study show that MMPs are expressed by resting zone and growth zone chondrocytes in culture and differentially distributed among three different membrane compartments. This suggests that, in addition to the well-known activators and inhibitors of MMP activity in the matrix, differential membrane distribution may enable more precise control over the site, rate, and extent of matrix degradation by the cell.
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PMID:Chondrocyte cultures express matrix metalloproteinase mRNA and immunoreactive protein; stromelysin-1 and 72 kDa gelatinase are localized in extracellular matrix vesicles. 876 42

Chronically sun-damaged human skin has a wrinkled, aged appearance as a result of alterations in the dermal extracellular matrix. Secondary effectors such as cytokines and integrins may mediate the effects of UV radiation on the skin by regulating the synthesis of metalloproteinases and structural proteins including collagen. The aim of this study was to semi-quantify the steady-state mRNA levels of interleukin-1 alpha, tumor necrosis factor alpha, transforming growth factor beta, collagenase, stromelysin, collagen, and integrins (alpha, and alpha2) in the skin of hairless mice that were either treated with UV or concurrently treated with UV and topical tretinoin for 5 weeks. Total RNA was extracted from the skin of the mice, reverse transcribed to cDNA, and amplified by the polymerase chain reaction in the presence of 32P-dCTP using gene-specific primers. Results were normalized relative to glyceraldehyde-3-phosphate dehydrogenase levels. Steady-state mRNA levels of the cytokines and integrins were increased by UV radiation. Concurrent UV and topical tretinoin treatment superinduced the expression of interleukin-1, increased alpha 1, and decreased alpha 2 integrin expression. Immunofluorescence analysis showed increased dermal localization of beta 1 integrin in UV and tretinoin treated skin. These results suggest that cytokines and integrins may be involved in the mechanism of photo-damage.
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PMID:Ultraviolet B radiation increases steady-state mRNA levels for cytokines and integrins in hairless mouse skin: modulation by topical tretinoin. 955 89

In liver, insulin stimulates the transcription of the gene encoding the cytosolic form of malic enzyme (ME) and modulates protein binding to two putative insulin response sequences (IRSs) in the ME promoter. One of these IRSs resembles that identified in the phosphoenolpyruvate carboxykinase (PEPCK) gene, whereas the other resembles that defined in the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene. To assess the functional significance of these changes in protein binding, a series of truncated ME-chloramphenicol acetyl-transferase (CAT) fusion genes were transiently transfected into rat H4IIE hepatoma cells. Deletion of the PEPCK-like IRS motif had no effect on the stimulation of CAT expression by insulin. Instead, the stimulatory effect of insulin was mediated through an AP-1 motif and an Egr-1 binding site that overlaps the GAPDH-like IRS motif. Both the ME AP-1 motif and the AP-1 motif identified in the collagenase-1 gene promoter were able to confer a stimulatory effect of insulin on the expression of a heterologous fusion gene, but surprisingly only the latter was able to confer a stimulatory effect of phorbol esters. Instead, the data suggest that AP-1 binds the ME AP-1 motif in an activated state such that phorbol ester treatment has no additional effect. The collagenase and ME AP-1 motifs were both shown to bind mainly Jun D and Fra-2, with similar affinities. However, the results of a proteolytic clipping bandshift assay suggest that these proteins bind the collagenase and ME AP-1 motifs in distinct conformations, which potentially explain the differences in phorbol ester signaling through these elements.
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PMID:A phorbol ester-insensitive AP-1 motif mediates the stimulatory effect of insulin on rat malic enzyme gene transcription. 981 2


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