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:3.1.6.4 (chondroitinase)
2,039 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fibronectin is a major surface protein of normal animal cells but is absent from many transformed cells. Addition of fibronectin to transformed cells causes increased cell substrate adhesion and changes in the morphology and cytoskeleton of the cells. We have coupled fibronectin to photoactivable chemical cross-linkers and have added it to cells to identify those molecules to which it binds. In this way, fibronectin can be cross-linked to sulfated proteoglycans at the cell surface. The cross-linking is specific for fibronectin. The fibronectin-proteoglycan complex is sensitive to chondroitinase ABC and AC and to trypsin. Addition of fibronectin also affects binding of hyaluronic acid to the cells. These results suggest that fibronectin interacts with proteoglycans at the cell surface. The existence of such interactions may have implications for the role of fibronectin and proteoglycans in cell adhesion.
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PMID:Cross-linking of fibronectin to sulfated proteoglycans at the cell surface. 22 72

Soluble 125I-labeled type I collagen binds to cultured fibroblasts but not to cultured epithelia. The binding of the ligand to fibroblasts is reversible, saturable and highly specific for sequences contained within the helical portions of the alpha1 and alpha2 chains. The amount of ligand bound is dependent upon cell number and ligand concentration. Binding is decreased but measurable at 4 degrees C. The steady state binding is greater at 26 degrees than at 37 degrees C due to a more rapid dissociation of the ligand-acceptor complex at 37 degrees C. The half-life of the complex is 46 min at 37 degrees C and approximately 2.5 hr at 26 degrees C. Scatchard plots of binding data indicate a single class of high affinity binding sites (KD = 1.2 X 10(-11) M) with each fibroblast binding approximately 500,000 molecules at saturation. Pretreatment of fibroblasts with bacterial collagenase, chondroitinase ABC or testicular hyaluronidase does not affect the binding reaction, whereas pretreatment of the cells with phospholipase C increases the amount of ligand bound. Ligand binding is decreased but not abolished after fibroblasts are treated with trypsin concentrations which remove surface fibronectin. Fibroblast monolayers treated with antiserum against fibronectin bind the radiolabeled ligand normally. In contrast to collagen, addition of excess fibronectin does not accelerate the dissociation of bound ligand from fibroblasts. Possible functions for surface-bound collagen are discussed.
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PMID:Binding of soluble type I collagen molecules to the fibroblast plasma membrane. 45 36

After immunization of mice with partially-purified heparan sulfate proteoglycan (HSPG) isolated from rat glomeruli, a monoclonal antibody (mAb JM-403) was obtained, which was directed against heparan sulfate (HS), the glycosaminoglycan side chain of HSPG. In ELISA it reacted with isolated human glomerular basement membrane (GBM) HSPG, HS and hyaluronic acid, but not with the core protein of human GBM HSPG, and not with chondroitin sulfate A and C, dermatan sulfate, keratan sulfate and heparin. Furthermore, it did not bind to laminin, collagen type IV or fibronectin. Specificity of JM-403 for HS was also suggested by results of inhibition studies, which found that intact HSPG and HS, but not the core protein, inhibited the binding of JM-403 to HS. In indirect immunofluorescence on cryostat sections of rat kidney, a fine granular to linear staining of the GBM was observed, along with a variable staining of the other renal basement membranes. Pretreatment of the sections with heparitinase completely prevented the binding of mAb JM-403, whereas pretreatment with chondroitinase ABC or hyaluronidase had no effect. The precise binding site of mAb JM-403 was investigated by indirect immunoelectron microscopy. It revealed a diffuse staining of the whole width of the GBM. One hour after intravenous injection of JM-403 into rats, the mAb was detected along the glomerular capillary wall in a fine granular pattern, which shifted towards a more mesangial localization after 24 hours. No binding was observed anymore by day 15. Intravenous injection induced a dose-dependent, transient and selective proteinuria that was maximal immediately after the injection.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A monoclonal antibody against GBM heparan sulfate induces an acute selective proteinuria in rats. 159 46

The initial step in hemopoiesis is the binding of progenitor cells to stroma. What mediates this binding at the molecular level is not entirely clear. We have previously reported that the cell line FDCP-1, a factor-dependent hemopoietic progenitor cell, actively synthesizes a membrane-associated chondroitin sulfate (CS) proteoglycan (MA-PG) which is unstable. After the binding of the progenitor cell to stromal, the stability of the MA-PG is enhanced, suggesting its involvement in the binding of progenitor cells to the stroma. Since stromal cells possess pericellular fibronectin (FN), we examined the possibility that binding to stromal cells may involve interactions between MA-PG of FDCP-1 on the one side and pericellular FN in stromal cells on the other side. To examine this hypothesis, we developed a cell adherence assay to measure the binding of FDCP-1 cells to a monolayer of stromal cells or to FN-coated dishes. Cell binding was inhibited by a monoclonal antibody against CS as well as by free CS and heparin, suggesting the involvement of MA-PG in the binding. Pretreatment of FDCP-1 cells with chondroitinase ABC, which selectively removes the CS portion of the MA-PG, also affects binding to the stromal cells. The binding was also inhibited by a pentapeptide (GRGDS) which competes with the cell-binding domain of FN as well as by a monoclonal antibody anti-FN. We conclude that interactions between MA-PG and a putative integrin-like molecule in FDCP-1 and the heparin and the cell binding domains in pericellular FN in the stromal cells contribute to the stabilization of progenitor-stromal cell binding which originally comes about by homing receptors of progenitor cells.
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PMID:Membrane-associated chondroitin sulfate proteoglycan and fibronectin mediate the binding of hemopoietic progenitor cells to stromal cells. 161 22

FN-C/H II is a heparin binding synthetic peptide from the C-terminal cell and heparin binding domain of fibronectin (FN) that mediates neuronal cell adhesion, spreading, and neurite outgrowth. Cellular interactions with FN-C/H II are inhibited by soluble heparin, suggesting that a cell-surface proteoglycan may mediate interactions with FN-C/H II (Haugen et al., 1990). To test this hypothesis further, heparan sulfate (HS) or chondroitin sulfate (CS) was removed from the cell surface by enzyme treatment. Heparitinase but not chondroitinase treatment of cells inhibited rat B104 neuroblastoma cell adhesion and spreading on FN-C/H II. Additionally, heparitinase treatment decreased the spreading of cells on the 33/66 kDa fragments containing the C-terminal heparin binding domain of FN. Furthermore, antibodies generated against a mouse melanoma HS proteoglycan (HSPG) inhibited B104 cell adhesion to FN-C/H II and the 33/66 kDa FN fragments. 35S-HSPG isolated from B104 cells directly bound to FN-C/H II both in solid phase assays and by affinity chromatography, but failed to bind to a control peptide from this region, CS1. The binding of 35S-HSPG was predominantly mediated by the HS and not the core protein of the HSPG. SDS-PAGE of iodinated HSPG demonstrated a single 78 kDa core protein following heparitinase digestion, which migrated at 51 kDa under nonreducing conditions. Anti-HSPG antibodies recognized the 78 kDa core protein by immunoblotting, and stained the surface of rat B104 neuroblastoma cells and cells of the primary neonatal rat nervous system. These results identify a cell-surface HSPG that likely mediates neuronal cell binding interactions with FN-C/H II.
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PMID:A cell-surface heparan sulfate proteoglycan mediates neural cell adhesion and spreading on a defined sequence from the C-terminal cell and heparin binding domain of fibronectin, FN-C/H II. 161 50

Chondroitin sulfate proteoglycans (CSPGs) are the major class of proteoglycans synthesized by mouse uterine stroma in vitro (Jacobs, A. L., and Carson, D. D. (1991). J. Biol. Chem. 266, 15,464-15,473). In the present study, stromal CSPGs were isolated and examined with regard to their ability to bind to specific extracellular matrix (ECM) components. Of a variety of ECM components tested, only collagen type I formed stable complexes with stromal CSPGs in both solid phase and solution binding assays. Proteolytic digestion of the CSPGs did not affect binding and suggested that the protein cores did not participate directly in binding. Furthermore, free chondroitin sulfate polysaccharides do not compete effectively in the binding assays. Therefore, interactions with multiple CS chains and/or the higher charge density afforded by intact CSPGs appear to be required for retention by collagen type I. Intact CSPGs were examined for their ability to modulate embryo attachment and outgrowth in vitro on fibronectin- or collagen type I-coated surfaces. In both cases, intact CSPGs, but not their constituent protein cores or polysaccharides, inhibited both the rate and the extent of outgrowth formation. In addition, embryo outgrowth on stromal ECM was enhanced by predigestion with chondroitinase. Addition of exogenous CSPG markedly retarded embryo outgrowth on stromal matrix. Collectively, these data indicate that stromal cell-derived CSPGs are retained by collagen type I in the stromal interstitial ECM where these molecules may attenuate trophoblast invasive behavior.
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PMID:Uterine stromal cell chondroitin sulfate proteoglycans bind to collagen type I and inhibit embryo outgrowth in vitro. 173 Mar 87

The lymphocyte-high endothelial venule (HEV) cell interaction is an essential element of the immune system, as it controls lymphocyte recirculation between blood and lymphoid organs in the body. This interaction involves an 85-95-kD class of lymphocyte surface glycoprotein(s), CD44. A subset of lymphocyte CD44 molecules is modified by covalent linkage to chondroitin sulfate (Jalkanen, S., M. Jalkanen, R. Bargatze, M. Tammi, and E. C. Butcher. 1988. J. Immunol. 141:1615-1623). In this work, we show that removal of chondroitin sulfate by chondroitinase treatment of lymphocytes or incubation of HEV with chondroitin sulfate does not significantly inhibit lymphocyte binding to HEV, suggesting that chondroitin sulfate is not involved in endothelial cell recognition of lymphocytes. Affinity-purified CD44 antigen was, on the other hand, observed to bind native Type I collagen fibrils, laminin, and fibronectin, but not gelatin. Binding to fibronectin was studied more closely, and it was found to be mediated through the chondroitin sulfate-containing form of the molecule. The binding site on fibronectin was the COOH-terminal heparin binding domain, because (a) the COOH-terminal heparin-binding fragment of fibronectin-bound isolated CD44 antigen; (b) chondroitin sulfate inhibited this binding; and (c) finally, the ectodomain of another cell surface proteoglycan, syndecan, which is known to bind the COOH-terminal heparin binding domain of fibronectin (Saunders, S., and M. Bernfield. 1988. J. Cell Biol. 106: 423-430), inhibited binding of CD44 both to intact fibronectin and to its heparin binding domain. Moreover, inhibition studies showed that binding of a lymphoblastoid cell line, KCA, to heparin binding peptides from COOH-terminal heparin binding fragment of fibronectin was mediated via CD44. These findings suggest that recirculating lymphocytes use the CD44 class of molecules not only for binding to HEV at the site of lymphocyte entry to lymphoid organs as reported earlier but also within the lymphatic tissue where CD44, especially the subset modified by chondroitin sulfate, is used for interaction with extracellular matrix molecules such as fibronectin.
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PMID:Lymphocyte CD44 binds the COOH-terminal heparin-binding domain of fibronectin. 173 Jul 78

After immunization with heparan sulfate proteoglycan (HSPG) isolated from human glomeruli, two mouse monoclonal antibodies (mAbs) against heparan sulfate (HS) were obtained. Both mAbs were of the IgM isotype and showed identical specificity. One of these, mAb JM-13 is described in detail. In enzyme-linked immunosorbent assay and Western blotting, reactivity was found with human glomerular basement membrane HSPG and HS. No binding occurred to the core protein of HSPG obtained after removal of HS with trifluoromethanesulfonic acid. In enzyme-linked immunosorbent assay, mAb JM-13 did neither bind to other proteoglycans, nor to other basement membrane components like collagen type IV, laminin, or fibronectin. In indirect immunofluorescence on cryostat sections of human kidneys, a restricted staining of tubular basement membranes was observed along with staining of the vascular basement membranes. In the glomerulus, a weak, fine granular staining was seen along the capillary wall and in the mesangium. MAb JM-13 bound also to the basolateral cell membranes of proximal tubular cells, to the cell membranes of cultured human and rat glomerular visceral epithelial cells, rat mesangial cells, human hepatocytes in culture, and in liver cryostat sections, indicating also a recognition of cell surface-associated HS. Pretreatment of the sections with heparitinase abolished binding of JM-13, whereas treatment with chondroitinase ABC had no effect. Inhibition studies in enzyme-linked immunosorbent assay as well as in indirect immunofluorescence corroborated the HS specificity of mAb JM-13. In conclusion, mAb JM-13 binds to an epitope on the HS chains of glomerular, tubular, and cell surface-associated HSPG.
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PMID:Production and characterization of a monoclonal antibody against human glomerular heparan sulfate. 189 Aug 9

A 22 x 10(3) Mr protein (abbreviated 22K) that copurifies with dermatan sulfate proteoglycans (DS-PGs) following the biochemical fractionation of bovine fetal skin has been evaluated for adhesion-promoting activity in vitro using Balb/c 3T3 cells, as well as bovine and human dermal fibroblasts. Substrata coated with 22K protein promote attachment of a subset of 3T3 and dermal fibroblasts that respond to plasma fibronectin (pFN) substrata. Cells on 22K protein display partial cytoplasmic spreading, comparable to that of cells adhering to cell-binding fragments of pFN. Adhesion activity of 22K is not due to contamination with known adhesive proteins of dermal matrices and is not dermal cell type-specific, since two classes of neuronal cells also respond effectively to 22K substrata. DS-PGs from cartilage or skin completely inhibit 22K adhesion activity when the PGs are adsorbed to 22K substrata under conditions prohibiting PGs from binding to substrata directly. Cartilage chondroitin/keratan sulfate proteoglycan at much higher concentrations is only partially inhibitory. Inhibition by DS-PGs is mediated by DS chains binding to 22K. Properties of the cell surface 'receptor' for 22K protein were tested by several approaches. It is not cell surface DS-PG, since: (1) cells unable to produce this proteoglycan class also responded; (2) cells treated with chondroitinase ABC responded equally well; and (3) substrata of proteoglycan-binding platelet factor-4 generated responses from cells that were quantitatively and qualitatively different. A synthetic peptide in the medium containing the Arg-Gly-Asp-Ser (RGDS) sequence completely inhibited responses to 22K substrata. This observation, coupled with sequencing data of 22K protein revealing an Arg-Gly-Ala-Thr sequence at residues 151-154, suggest that 22K protein mediates adhesion by cell surface integrin binding. Therefore, this newly discovered matrix protein from skin may serve as a communication link between the dermal fibroblast cell surface and its extracellular matrix environment.
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PMID:Extracellular matrix adhesion-promoting activities of a dermatan sulfate proteoglycan-associated protein (22K) from bovine fetal skin. 193 76

Primary cultures of meningeal cells from embryonic rat cerebra secrete neurite growth-inducing components into serum-free culture medium. This conditioned medium (CM) was analyzed by FPLC and immunochemical and enzymatic treatments and tested for neurite promoting activity (NPA) in a quantitative bioassay using hippocampal neurons from embryonic rat. By immunoprecipitation or specific adsorption we identified laminin (LN)-proteoglycan complexes and fibronectin (FN), respectively, as the major neurite promoting components within meningeal cell CM. The LN-proteoglycan complexes and their NPA were sensitive to chondroitinase (chondroitin ABC lyase, EC 4.2.2.4) and to a smaller extent to heparitinase (heparitin sulfate lyase, EC 4.2.2.8). Minor fractions of the total NPA in CM correlated with free LN and a putative but not yet characterized FN-proteoglycan complex.
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PMID:Identification of meningeal cell released neurite promoting activities for embryonic hippocampal neurons. 199 93


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