scholarly journals Functional characterization of chondroitin sulfate proteoglycans of brain: interactions with neurons and neural cell adhesion molecules.

1993 ◽  
Vol 120 (3) ◽  
pp. 815-824 ◽  
Author(s):  
M Grumet ◽  
A Flaccus ◽  
R U Margolis
Keyword(s):  
Cell Adhesion ◽  
Chondroitin Sulfate ◽  
Adhesion Molecules ◽  
Cell Adhesion Molecules ◽  
Core Protein ◽  
Functional Characterization ◽  
Adult Brain ◽  
Chondroitin Sulfate Proteoglycans ◽  
Core Proteins ◽  
Cell Adhesion And Migration

Ng-CAM and N-CAM are cell adhesion molecules (CAMs), and each CAM can bind homophilically as demonstrated by the ability of CAM-coated beads (Covaspheres) to self-aggregate. We have found that the extent of aggregation of Covaspheres coated with either Ng-CAM or N-CAM was strongly inhibited by the intact 1D1 and 3F8 chondroitin sulfate proteoglycans of rat brain, and by the core glycoproteins resulting from chondroitinase treatment of the proteoglycans. Much higher concentrations of rat chondrosarcoma chondroitin sulfate proteoglycan (aggrecan) core proteins had no significant effect in these assays. The 1D1 and 3F8 proteoglycans also inhibited binding of neurons to Ng-CAM when mixtures of these proteins were adsorbed to polystyrene dishes. Direct binding of neurons to the proteoglycan core glycoproteins from brain but not from chondrosarcoma was demonstrated using an assay in which cell-substrate contact was initiated by centrifugation, and neuronal binding to the 1D1 proteoglycans was specifically inhibited by the 1D1 monoclonal antibody. Different forms of the 1D1 proteoglycan have been identified in developing and adult brain. The early postnatal form (neurocan) was found to bind neurons more effectively than the adult proteoglycan, which represents the C-terminal half of the larger neurocan core protein. Our results therefore indicate that certain brain proteoglycans can bind to neurons, and that Ng-CAM and N-CAM may be heterophilic ligands for neurocan and the 3F8 proteoglycan. The ability of these brain proteoglycans to inhibit adhesion of cells to CAMs may be one mechanism to modulate cell adhesion and migration in the nervous system.

scholarly journals Membrane-associated chondroitin sulfate proteoglycans of human lung fibroblasts.

1989 ◽  
Vol 108 (3) ◽  
pp. 1165-1173 ◽  
Author(s):  
G David ◽  
V Lories ◽  
A Heremans ◽  
B Van der Schueren ◽  
J J Cassiman ◽  
...  
Keyword(s):  
Chondroitin Sulfate ◽  
Human Lung ◽  
Core Protein ◽  
Human Fibroblasts ◽  
Chondroitin Sulfate Proteoglycans ◽  
Lung Fibroblasts ◽  
Hydrophobic Membrane ◽  
Human Lung Fibroblasts ◽  
Core Proteins

Cultured human fetal lung fibroblasts produce some chondroitin sulfate proteoglycans that are extracted as an aggregate in chaotropic buffers containing 4 M guanidinium chloride. The aggregated proteoglycans are excluded from Sepharose CL4B and 2B, but become included, eluting with a Kav value of 0.53 from Sepharose CL4B, when Triton X-100 is included in the buffer. Conversely, some of the detergent-extractable chondroitin sulfate proteoglycans can be incorporated into liposomes, suggesting the existence of a hydrophobic membrane-intercalated chondroitin sulfate proteoglycan fraction. Purified preparations of hydrophobic chondroitin sulfate proteoglycans contain two major core protein forms of 90 and 52 kD. A monoclonal antibody (F58-7D8) obtained from the fusion of myeloma cells with spleen cells of BALB/c mice that were immunized with hydrophobic proteoglycans recognized the 90- but not the 52-kD core protein. The epitope that is recognized by the antibody is exposed at the surface of cultured human lung fibroblasts and at the surface of several stromal cells in vivo, but also at the surface of Kupffer cells and of epidermal cells. The core proteins of these small membrane-associated chondroitin sulfate proteoglycans are probably distinct from those previously identified in human fibroblasts by biochemical, immunological, and molecular biological approaches.

scholarly journals The neuronal chondroitin sulfate proteoglycan neurocan binds to the neural cell adhesion molecules Ng-CAM/L1/NILE and N-CAM, and inhibits neuronal adhesion and neurite outgrowth.

1994 ◽  
Vol 125 (3) ◽  
pp. 669-680 ◽  
Author(s):  
D R Friedlander ◽  
P Milev ◽  
L Karthikeyan ◽  
R K Margolis ◽  
R U Margolis ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Chondroitin Sulfate ◽  
Adhesion Molecules ◽  
Cell Adhesion Molecules ◽  
Neurite Growth ◽  
Chondroitin Sulfate Proteoglycan ◽  
Sulfate Proteoglycan ◽  
Neural Cell Adhesion Molecules ◽  
Neural Cell Adhesion ◽  
Neuronal Adhesion

We have previously shown that aggregation of microbeads coated with N-CAM and Ng-CAM is inhibited by incubation with soluble neurocan, a chondroitin sulfate proteoglycan of brain, suggesting that neurocan binds to these cell adhesion molecules (Grumet, M., A. Flaccus, and R. U. Margolis. 1993. J. Cell Biol. 120:815). To investigate these interactions more directly, we have tested binding of soluble 125I-neurocan to microwells coated with different glycoproteins. Neurocan bound at high levels to Ng-CAM and N-CAM, but little or no binding was detected to myelin-associated glycoprotein, EGF receptor, fibronectin, laminin, and collagen IV. The binding to Ng-CAM and N-CAM was saturable and in each case Scatchard plots indicated a high affinity binding site with a dissociation constant of approximately 1 nM. Binding was significantly reduced after treatment of neurocan with chondroitinase, and free chondroitin sulfate inhibited binding of neurocan to Ng-CAM and N-CAM. These results indicate a role for chondroitin sulfate in this process, although the core glycoprotein also has binding activity. The COOH-terminal half of neurocan was shown to have binding properties essentially identical to those of the full-length proteoglycan. To study the potential biological functions of neurocan, its effects on neuronal adhesion and neurite growth were analyzed. When neurons were incubated on dishes coated with different combinations of neurocan and Ng-CAM, neuronal adhesion and neurite extension were inhibited. Experiments using anti-Ng-CAM antibodies as a substrate also indicate that neurocan has a direct inhibitory effect on neuronal adhesion and neurite growth. Immunoperoxidase staining of tissue sections showed that neurocan, Ng-CAM, and N-CAM are all present at highest concentration in the molecular layer and fiber tracts of developing cerebellum. The overlapping localization in vivo, the molecular binding studies, and the striking effects on neuronal adhesion and neurite growth support the view that neurocan may modulate neuronal adhesion and neurite growth during development by binding to neural cell adhesion molecules.

scholarly journals Hox Transcription Factors: Modulators of Cell-Cell and Cell-Extracellular Matrix Adhesion

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Yasushi Taniguchi
Keyword(s):  
Extracellular Matrix ◽  
Transcription Factors ◽  
Cell Adhesion ◽  
Adhesion Molecules ◽  
Cell Adhesion Molecules ◽  
Cultured Cells ◽  
Hox Proteins ◽  
Cell Adhesion And Migration ◽  
And Migration ◽  
Cell Cell

Hoxgenes encode homeodomain-containing transcription factors that determine cell and tissue identities in the embryo during development.Hoxgenes are also expressed in various adult tissues and cancer cells. InDrosophila, expression of cell adhesion molecules, cadherins and integrins, is regulated by Hox proteins operating in hierarchical molecular pathways and plays a crucial role in segment-specific organogenesis. A number of studies using mammalian cultured cells have revealed that cell adhesion molecules responsible for cell-cell and cell-extracellular matrix interactions are downstream targets of Hox proteins. However, whether Hox transcription factors regulate expression of cell adhesion molecules during vertebrate development is still not fully understood. In this review, the potential roles Hox proteins play in cell adhesion and migration during vertebrate body patterning are discussed.

scholarly journals Synaptic neurexin-1 assembles into dynamically regulated active zone nanoclusters

2019 ◽  
Vol 218 (8) ◽  
pp. 2677-2698 ◽  
Author(s):  
Justin H. Trotter ◽  
Junjie Hao ◽  
Stephan Maxeiner ◽  
Theodoros Tsetsenis ◽  
Zhihui Liu ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Adhesion Molecules ◽  
Active Zone ◽  
Cell Adhesion Molecules ◽  
Super Resolution ◽  
Adult Brain ◽  
Excitatory Synapses ◽  
Synaptic Localization ◽  
Organizational Feature ◽  
Super Resolution Microscopy

Neurexins are well-characterized presynaptic cell adhesion molecules that engage multifarious postsynaptic ligands and organize diverse synapse properties. However, the precise synaptic localization of neurexins remains enigmatic. Using super-resolution microscopy, we demonstrate that neurexin-1 forms discrete nanoclusters at excitatory synapses, revealing a novel organizational feature of synaptic architecture. Synapses generally contain a single nanocluster that comprises more than four neurexin-1 molecules and that also includes neurexin-2 and/or neurexin-3 isoforms. Moreover, we find that neurexin-1 is physiologically cleaved by ADAM10 similar to its ligand neuroligin-1, with ∼4–6% of neurexin-1 and ∼2–3% of neuroligin-1 present in the adult brain as soluble ectodomain proteins. Blocking ADAM10-mediated neurexin-1 cleavage dramatically increased the synaptic neurexin-1 content, thereby elevating the percentage of Homer1(+) excitatory synapses containing neurexin-1 nanoclusters from 40–50% to ∼80%, and doubling the number of neurexin-1 molecules per nanocluster. Taken together, our results reveal an unexpected nanodomain organization of synapses in which neurexin-1 is assembled into discrete presynaptic nanoclusters that are dynamically regulated via ectodomain cleavage.

scholarly journals Interactions of the chondroitin sulfate proteoglycan phosphacan, the extracellular domain of a receptor-type protein tyrosine phosphatase, with neurons, glia, and neural cell adhesion molecules.

1994 ◽  
Vol 127 (6) ◽  
pp. 1703-1715 ◽  
Author(s):  
P Milev ◽  
D R Friedlander ◽  
T Sakurai ◽  
L Karthikeyan ◽  
M Flad ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Chondroitin Sulfate ◽  
Adhesion Molecules ◽  
Cell Adhesion Molecules ◽  
Tyrosine Phosphatase ◽  
Neurite Growth ◽  
Neural Cell ◽  
Neural Cell Adhesion Molecules ◽  
Neural Cell Adhesion ◽  
The Central Nervous System

Phosphacan is a chondroitin sulfate proteoglycan produced by glial cells in the central nervous system, and represents the extracellular domain of a receptor-type protein tyrosine phosphatase (RPTP zeta/beta). We previously demonstrated that soluble phosphacan inhibited the aggregation of microbeads coated with N-CAM or Ng-CAM, and have now found that soluble 125I-phosphacan bound reversibly to these neural cell adhesion molecules, but not to a number of other cell surface and extracellular matrix proteins. The binding was saturable, and Scatchard plots indicated a single high affinity binding site with a Kd of approximately 0.1 nM. Binding was reduced by approximately 15% after chondroitinase treatment, and free chondroitin sulfate was only moderately inhibitory, indicating that the phosphacan core glycoprotein accounts for most of the binding activity. Immunocytochemical studies of embryonic rat spinal phosphacan, Ng-CAM, and N-CAM have overlapping distributions. When dissociated neurons were incubated on dishes coated with combinations of phosphacan and Ng-CAM, neuronal adhesion and neurite growth were inhibited. 125I-phosphacan bound to neurons, and the binding was inhibited by antibodies against Ng-CAM and N-CAM, suggesting that these CAMs are major receptors for phosphacan on neurons. C6 glioma cells, which express phosphacan, adhered to dishes coated with Ng-CAM, and low concentrations of phosphacan inhibited adhesion to Ng-CAM but not to laminin and fibronectin. Our studies suggest that by binding to neural cell adhesion molecules, and possibly also by competing for ligands of the transmembrane phosphatase, phosphacan may play a major role in modulating neuronal and glial adhesion, neurite growth, and signal transduction during the development of the central nervous system.

scholarly journals Expression sequences and distribution of two primary cell adhesion molecules during embryonic development of Xenopus laevis.

1987 ◽  
Vol 105 (5) ◽  
pp. 2359-2372 ◽  
Author(s):  
G Levi ◽  
K L Crossin ◽  
G M Edelman
Keyword(s):  
Cell Adhesion ◽  
Xenopus Laevis ◽  
Adhesion Molecules ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecules ◽  
Cell Adhesion Molecule ◽  
Adult Brain ◽  
Neural Ectoderm ◽  
Sensory Layer ◽  
Endodermal Cells

Studies of chicken embryos have demonstrated that cell adhesion molecules are important in embryonic induction and are expressed in defined sequences during embryogenesis and histogenesis. To extend these observations and to provide comparable evidence for heterochronic changes in such sequences during evolution, the local distributions of the neural cell adhesion molecule (N-CAM) and of the liver cell adhesion molecule (L-CAM) were examined in Xenopus laevis embryos by immunohistochemical and biochemical techniques. Because of the technical difficulties presented by the existence of multiple polypeptide forms of CAMs and by autofluorescence of yolk-containing cells, special care was taken in choosing and characterizing antibodies, fluorophores, and embedding procedures. Both N-CAM and L-CAM were found at low levels in pregastrulation embryos. During gastrulation, N-CAM levels increased in the presumptive neural epithelium and decreased in the endoderm, but L-CAM continued to be expressed in all cells including endodermal cells. During neurulation, the level of N-CAM expression in the neural ectoderm increased considerably, while remaining constant in non-neural ectoderm and diminishing in the somites; in the notochord, N-CAM was expressed transiently. Prevalence modulation was also seen at all sites of secondary induction: both CAMs increased in the sensory layer of the ectoderm during condensation of the placodes. During organogenesis, the expression of L-CAM gradually diminished in the nervous system while N-CAM expression remained high. In all other organs examined, the amount of one or the other CAM decreased, so that by stage 50 these two molecules were expressed in non-overlapping territories. Embryonic and adult tissues were compared to search for concordance of CAM expression at later stages. With few exceptions, the tissue distributions of N-CAM and L-CAM were similar in the frog and in the chicken from early times of development. In contrast to previous observations in the chicken and in the mouse, N-CAM expression was found to be high in the adult liver of Xenopus, whereas L-CAM expression was low. In the adult brain, N-CAM was expressed as three components of apparent molecular mass 180, 140, and 120 kD, respectively; in earlier stages of development only the 140-kD component could be detected. In the liver, a single N-CAM band appears at 160 kD, raising the possibility that this band represents an unusual N-CAM polypeptide. L-CAM appeared at all stages as a 124-kD molecule.(ABSTRACT TRUNCATED AT 400 WORDS)

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