scholarly journals Phosphacan, a chondroitin sulfate proteoglycan of brain that interacts with neurons and neural cell-adhesion molecules, is an extracellular variant of a receptor-type protein tyrosine phosphatase.

1994 ◽  
Vol 91 (7) ◽  
pp. 2512-2516 ◽  
Author(s):  
P. Maurel ◽  
U. Rauch ◽  
M. Flad ◽  
R. K. Margolis ◽  
R. U. Margolis
Keyword(s):  
Cell Adhesion ◽  
Chondroitin Sulfate ◽  
Adhesion Molecules ◽  
Protein Tyrosine Phosphatase ◽  
Cell Adhesion Molecules ◽  
Tyrosine Phosphatase ◽  
Chondroitin Sulfate Proteoglycan ◽  
Sulfate Proteoglycan ◽  
Neural Cell Adhesion Molecules ◽  
Neural Cell Adhesion

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 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 OF NEURAL CELL ADHESION MOLECULES IN THE MOUSE ANTERIOR PITUITARY GLAND AND PITUITARY TUMOR CELLS

1998 ◽  
Vol 19 (4) ◽  
pp. 269-277
Author(s):  
YOSHIHIRO YAYOI ◽  
SUMIO TAKAHASHI ◽  
SAKAE TAKEUCHI ◽  
MAKOTO TAKEUCHI ◽  
TATSUNORI SEKI ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Pituitary Gland ◽  
Tumor Cells ◽  
Adhesion Molecules ◽  
Cell Adhesion Molecules ◽  
Pituitary Tumor ◽  
Anterior Pituitary ◽  
Neural Cell ◽  
Neural Cell Adhesion Molecules ◽  
Neural Cell Adhesion

Neural cell adhesion molecules during embryonic induction and development of the kidney

Development ◽  
1988 ◽  
Vol 102 (4) ◽  
pp. 749-761 ◽  
Author(s):  
G. Klein ◽  
M. Langegger ◽  
C. Goridis ◽  
P. Ekblom
Keyword(s):  
Cell Adhesion ◽  
Adhesion Molecules ◽  
Cell Adhesion Molecules ◽  
Kidney Development ◽  
Neural Cell ◽  
Cell Polarization ◽  
Embryonic Induction ◽  
Neural Cell Adhesion Molecules ◽  
Short Period ◽  
Neural Cell Adhesion

The neural cell adhesion molecules (N-CAM) are a family of related glycoproteins with Mr of 180, 140 and 120 × 10(3) (180K etc.). In the embryo, they are often highly sialylated and migrate as a diffuse band of 170–250K. N-CAM are found in non-neural tissues and we have now studied the expression of N-CAM in the developing mouse kidney. During kidney development, a unique conversion of a mesenchyme to an epithelium occurs and it is thought that this is mediated by an increase in cell adhesivity. By immunofluorescence, we show that N-CAM is present already at onset of kidney development on the cells of the uninduced nephrogenic mesenchyme. After induction, when the cells convert into an epithelium, they lose N-CAM gradually and instead begin to express uvomorulin, another primary CAM. By using an organ culture model, we could rather precisely show that N-CAM and uvomorulin are coexpressed for a short period, but, when epithelial cell polarization is evident, only uvomorulin is present on the epithelium, whereas N-CAM is confined to the surrounding mesenchyme. Immunoblotting for N-CAM revealed that the ‘embryonic’ form of N-CAM, the broad 170–250K band was not present in the embryonic kidney, which instead expressed the three distinct 180K, 140K and 120K bands typical of adult neurones. The 180K and 140K bands were gradually lost during development and were no longer detectable in adult kidneys. By using an N-CAM cDNA, we detected three different mRNAs of 7.4, 6.7 and 4.3 kb in the developing kidney, but this expression was restricted to the embryonic and early postnatal stages. No transcripts were detectable in adult kidneys. The studies do not support the hypothesis that N-CAM expression in the kidney is turned on by embryonic induction. Rather, we suggest that N-CAM are important adhesives for the predetermined, but not yet induced, nephrogenic mesenchyme.

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