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:3.1.3.5 (5'-nucleotidase)
3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ecto-enzyme 5'-nucleotidase isolated from chicken gizzard has previously been shown to be a potent ligand of two glycoproteins of the extracellular matrix, namely fibronectin and laminin. Using immunofluorescent labeling techniques we observed that 5'-nucleotidase codistributed with laminin during the development of chicken striated muscle. In contrast, ecto-5'-nucleotidase was only faintly detectable on cells surrounded by a matrix expressing high levels of fibronectin. This distribution pattern distinguished 5'-nucleotidase from the pluripotent extracellular matrix receptors, chicken beta 1-integrins, which are expressed equally well in muscle and connective tissue. In addition, the specific activity of striated muscle ecto-5'-nucleotidase was stable during development and increased markedly posthatching. At each age considered, this specific activity corresponded to an 80-kDa enzyme which was inhibited by alpha,beta-methyleneadenosine diphosphate or by a monoclonal antibody directed against the smooth muscle isoform of the enzyme. Previous in vitro studies have revealed that 5'-nucleotidase is involved in the spreading of various mesenchyme-derived cells, such as chicken embryonic fibroblasts and myoblasts, on a laminin substrate. A prerequisite to examining a potential in vivo role for 5'-nucleotidase as an extracellular matrix ligand was to study its distribution. In adult muscle, 5'-nucleotidase displayed a more restricted distribution than in embryo. Results show that, in vivo, 5'-nucleotidase is revealed by immunofluorescent labeling using poly- and monoclonal antibodies to chicken gizzard 5'-nucleotidase in two structures, the costameres and myotendinous junctions, which are closely related to the focal adhesion sites observed in cell culture.
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PMID:Enzymatic activity and in vivo distribution of 5'-nucleotidase, an extracellular matrix binding glycoprotein, during the development of chicken striated muscle. 133 Jun 59

Modulation of 5'-nucleotidase activity by the extracellular matrix proteins fibronectin, laminin and their fragments has been studied in plasma membrane preparations as well as in intact BCS-TC2 and Rugli cells. The ectoenzyme on plasma membranes is activated by laminin; fibronectin inhibits the AMPase activity on BCS-TC2 plasma membranes but no inhibitory effect is found in plasma membrane preparations from Rugli cells. These effects are dependent on the preincubation time and protein concentration. When the effect of the extracellular matrix proteins is studied on intact cells, both BCS-TC2 and Rugli cells show similar behaviour. A decrease in the enzyme activity is observed in the presence of fibronectin. The AMPase inhibitory activity is located on its 40 kDa fragment. No inhibitory activity is found in other fibronectin fragments, including the 140 kDa fragment which contains the RGDS cell-adhesion sequence. Laminin and its E1-4 and E8 fragments are able to activate the ecto-5'-nucleotidase activity of both BCS-TC2 and Rugli cells. The effect of the E1-4 fragment on intact cells is greater than that observed for the E8 fragment and uncleaved laminin. Our results suggest a bifunctional role for 5'-nucleotidase as ectoenzyme and cell receptor for extracellular matrix proteins.
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PMID:Modulation of 5'-nucleotidase activity in plasma membranes and intact cells by the extracellular matrix proteins laminin and fibronectin. 154 Jan 33

The seminal vesicles originate in embryos of about 58 mm crown-rump-length from the Wolffian duct under the influence of testosterone. Along with the ampulla of the vas deferens and the ejaculatory duct, they form a functional unit that develops slowly until the onset of puberty. Developmental malformations occur as uni- or bilateral agenesis, aplasia, cysts, or ureterovesicular fistules. After puberty, the glands form sac-like structures which have a capacity of about 3.4-4.5 ccm and contribute about 70% of the seminal fluid. In addition to secretion, they are capable of reabsorption of fluids or dissolved substances, and of spermatophagy (ingestion and degradation of damaged spermatozoa by epithelial cells). Secretory activity of the glands is a measure of testosterone supplementation to the epithelium. Nervous regulation of secretion is realized by cholinergic post-ganglionic, sympathetic (and perhaps parasympathetic) fibres, derived from pelvic plexus. Contraction of the muscular wall occurs under the influence of excitatory adrenergic and modulatory NPY-encephalin-peptidergic nerve fibres. The secretory products of the seminal vesicles encompass (1) ions (K+: 1.1 mM ml-1) (2) low molecular weight substances (fructose: above 1.2 mg ml-1; prostaglandins above 250 microliters ml-1, (3) peptides (endorphin: 330 pg ml-1), and (4) proteins. In addition to plasma protein related forms such as transferrin, lactoferrin, and fibronectin, specific proteins such as semenogelin (52 kDa) are synthesized, the scaffold protein of semen coagulate forming the substrate for PSA (prostate specific antigen), sperm motility inhibitor (ca. 18 kDa), and others (placental protein 5, protein kinase inhibitor, carboanhydrase, 5'-nucleotidase), some of which are immunosuppressive. Therefore, functions of the seminal vesicles concern (a) formation of seminal coagulum, (b) modification of sperm functions (motility, capacitation), and (c) immunosuppression. Additional functions within the female genital system, perhaps during pre-implantation period, are likely, but remain to be proven experimentally.
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PMID:Morphology and functions of the human seminal vesicle. 164 33

Four mouse monoclonal antibodies (PTN63, PTN108, PTN124, PTN514) against the ecto-5'-nucleotidase purified from a human pancreatic adenocarcinoma cell line (PaTu II) have been raised and characterized. All four monoclonal antibodies recognize the protein moiety of the glycosylated ecto-5'-nucleotidase. In competition assays it was demonstrated that three of the antibodies (PTN63, PTN108, PTN514) recognize different epitopes within the protein moiety. Furthermore, PTN108, PTN124, and PTN514 reduced the 5'-nucleotidase AMPase activity in contrast to PTN63 having no inhibitory effect. The antibodies show no cross-reactivity with ecto-5'-nucleotidases from rat liver, bull seminal plasma, chicken gizzard and human peripheral blood cells. When assayed by indirect immunofluorescence the antibodies react with the plasma membrane of human pancreatic tumor cells with varying staining intensity. Immunocytochemistry on paraffin sections of normal human pancreas revealed a prominent staining of the pancreatic duct cells. No staining of the acinar and islet cells could be detected. Thus, 5'-nucleotidase is a marker enzyme for pancreatic duct cells and can be used to determine the origin of pancreatic tumor cells. PTN63 reduced the attachment to fibronectin substratum of a human pancreatic adenocarcinoma tumor cell line possessing a high amount of plasma membrane bound ecto-5'-nucleotidase, but had no effect on a cell line lacking the membrane bound AMPase. In contrast, PTN108 and PTN514, which inhibit the AMPase activity, exhibited no influence on the adhesion of human pancreatic tumor cells to fibronectin substratum.
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PMID:Monoclonal antibodies against 5'-nucleotidase from a human pancreatic tumor cell line: their characterization and inhibitory capacity on tumor cell adhesion to fibronectin substratum. 164 65

The smooth muscle cells of chicken gizzard harbor the ectoenzyme 5'-nucleotidase. The purified enzyme was reconstituted into 3H-labeled proteoliposomes which were used as a model to study the association of a membrane protein with fibronectin. We demonstrated that the binding process between proteoliposomes and fibronectin has the qualities of a receptor-ligand interaction, i.e., is saturable and specific. In contrast to the association of fibronectin with integrins, the interaction with 5'-nucleotidase does not require divalent metal ions. Synthetic peptides containing the RGD-sequence or a monoclonal antibody interfering with binding of other receptors to the cell-binding domain of fibronectin did not abolish the interaction with 5'-nucleotidase. This indicates that the RGDS-sequence does not represent the major contact site for the AMPase and that the 5'-nucleotidase belongs to a separate class of fibronectin receptors with distinct properties as compared to the integrins.
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PMID:Chicken gizzard 5'-nucleotidase is a receptor for the extracellular matrix component fibronectin. 214 Sep 85

The reversibility of hepatic fibrosis was investigated in an experimental model of extrahepatic cholestasis in the rat after common bile duct ligation for 2 weeks, followed by bilioduodenal anastomosis for 3 weeks. Bile duct ligation resulted in a transitory marked elevation in the serum concentration of 5'-nucleotidase, alkaline phosphatase, and bilirubin during the first 3 days. Then these levels decreased to threefold, twofold, and 100-fold the normal values, respectively, during the following 4 weeks. Histologic examination of the liver disclosed extensive bile duct proliferation and the formation of periportal fibrosis, with only slight inflammation and necrosis. The distribution of the major components of the hepatic extracellular matrix was analyzed 2 weeks after bile duct ligation, using the indirect immunoperoxidase method. Fibrous septa were found to be strongly stained for collagens I, pro-III, III and IV, fibronectin, and laminin. The most intense staining was found in enlarged periportal areas, collagen IV and laminin being particularly abundant around newly formed bile ducts. These changes paralleled high steady-state levels of alpha 1(I) and alpha 1(IV) collagen and B2 chain laminin mRNAs. Relief of the obstruction for 2 weeks resulted in a shift in the serum concentration of 5'-nucleotidase, alkaline phosphatase, and bilirubin toward normal values. A dramatic resorption of bile duct proliferations and periportal fibrosis were observed. Three weeks after bile duct repermeabilization, immunohistochemical study showed that the pattern of distribution of extracellular matrix components was almost normal, except for collagen IV, which remained abundant in the sinusoids when compared with the normal liver. In parallel, the steady-state B2-chain laminin mRNA level became lower than in cholestatic livers, whereas alpha 1(I) and alpha 1(IV) mRNAs were almost undetectable. These results show that hepatic fibrosis induced by experimental extrahepatic cholestasis in rat disappears in less than 3 weeks after relief of bile duct obstruction, suggesting that an active degradation of matrix protein occurs, except for collagen IV in the sinusoid.
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PMID:Reversibility of hepatic fibrosis in experimentally induced cholestasis in rat. 226 Jun 23

Previous studies have shown that 5'-nucleotidase, an ectoenzyme from chicken gizzard, interacts specifically with laminin and fibronectin, two glycoproteins of the extracellular matrix. Recently, we demonstrated that 5'-nucleotidase was involved in the spreading of chick embryo fibroblast on laminin. In the present communication, we report that a monoclonal antibody (CG37) raised-directed against 5'-nucleotidase inhibited the spreading of chick embryo myoblasts on laminin after their initial attachment to the substrate. Furthermore, monoclonal antibody CG37 specifically eluted 5'-nucleotidase from immobilized laminin and thus enabled its isolation from other myoblast laminin-binding proteins.
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PMID:5'-Nucleotidase is involved in chick embryo myoblast spreading on laminin. 231 76

The ectoenzyme 5'-nucleotidase purified from chicken gizzard is shown to specifically interact with laminin and fibronectin, components of the extracellular matrix, by a number of different techniques: (i) cosedimentation with laminin by sucrose gradient centrifugation; (ii) affinity adsorption to both laminin- and fibronectin-Sepharose 4-B; (iii) specific binding to both laminin and fibronectin dotted onto cellulose filters; and (iv) monoclonal antibodies against 5'-nucleotidase are shown to interfere with the interaction of 5'-nucleotidase with laminin and fibronectin. For all the techniques employed, the interactions were found to be specific, since 5'-nucleotidase did not bind to unrelated proteins such as bovine serum albumin or to monomeric actin. The interaction of purified chicken gizzard 5'-nucleotidase could be demonstrated for the hydrophobic enzyme solubilized in detergent and after its reconstitution into artificial phospholipid vesicles. The affinity adsorption experiments indicate that reconstituted enzyme binds more strongly to both laminin and fibronectin. The 5'-nucleotidase employed in this study is anchored to the plasma membrane by a glycan-phosphatidylinositol linker. After treatment with phosphatidylinositol-specific phospholipase C, the enzyme is transformed into a hydrophilic form, for which interactions with laminin and fibronectin could also be demonstrated by the dot-blot technique. Thus controlled cleavage of the phosphatidylinositol linker of 5'-nucleotidase could enable cells to rapidly alter their adhesiveness to certain components of the extracellular matrix.
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PMID:Evidence for the direct interaction of chicken gizzard 5'-nucleotidase with laminin and fibronectin. 255 83

Polyclonal and monoclonal antibodies raised against chicken gizzard 5'-nucleotidase were tested in adhesion assays of embryonic chicken fibroblasts (CEF) for their ability to interfere with the adhesion process of these cells on either laminin or fibronectin substrata. The initial attachment process of CEF on fibronectin and laminin substrata was not influenced by preincubating these cells with antibodies against chicken gizzard 5'-nucleotidase. However, the subsequent spreading process of these cells was found to be inhibited for at least 2 h on a laminin substratum. This effect was obtained with a polyclonal antibody as well as with one from 12 monoclonal antibodies raised against the native enzyme purified from chicken gizzard. In vitro assays demonstrated a competition of laminin and this monoclonal antibody for the binding site on purified 5'-nucleotidase. Spreading-arrested and rounded CEF do not develop prominent intracellular stress-fibers like control cells, instead they seem to concentrate their available actin in areas of presumptive initial contact with the laminin substratum.
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PMID:Polyclonal and monoclonal antibodies against chicken gizzard 5'-nucleotidase inhibit the spreading process of chicken embryonic fibroblasts on laminin substratum. 282 84

Laminin and fibronectin, but not collagen, affect the AMPase activity of the purified transmembrane protein 5'-nucleotidase. Laminin stimulates whereas fibronectin inhibits the AMPase activity of this ectoenzyme. The AMPase-modulating effects by these components of the extracellular matrix require a preincubation period of several hours when detergent-solubilized 5'-nucleotidase is employed, they can, however, instantaneously be elicited with liposome-incorporated 5'-nucleotidase.
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PMID:The extracellular matrix proteins laminin and fibronectin modify the AMPase activity of 5'-nucleotidase from chicken gizzard smooth muscle. 300 58


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