Structure of a new nervous system glycoprotein, Nr-CAM, and its relationship to subgroups of neural cell adhesion molecules (original) (raw)
Related papers
Homophilic and heterophilic binding activities of Nr-CAM, a nervous system cell adhesion molecule
The Journal of Cell Biology, 1992
Nr-CAM is a membrane glycoprotein that is expressed on neurons. It is structurally related to members of the N-CAM superfamily of neural cell adhesion molecules having six immunoglobulin-like domains and five fibronectin type III repeats in the extracellular region. We have found that the aggregation of chick brain cells was inhibited by anti-Nr-CAM Fab' fragments, indicating that Nr-CAM can act as a cell adhesion molecule. To clarify the mode of action of Nr-CAM, a mouse fibroblast cell line L-M(TK-) (or L cells) was transfected with a DNA expression construct encoding an entire chicken Nr-CAM cDNA sequence. After transfection, L cells expressed Nr-CAM on their surface and aggregated. Aggregation was specifically inhibited by anti-Nr-CAM Fab' fragments. To check the specificity of this aggregation, a fusion protein (FGTNr) consisting of glutathione S-transferase linked to the six immunoglobulin domains and the first fibronectin type III repeat of Nr-CAM was expressed in Esc...
The Journal of Cell Biology, 1985
The rodent neural cell adhesion molecule (N-CAM) consists of three glycoprotein chains of 180, 140, and 120 kD in their adult forms. Although the proportions of the three components are known to change during development and differ between brain regions, their individual distribution and function are unknown. Here we report studies carried out with a monoclonal antibody that specifically recognizes the 180-kD component of mouse N-CAM (N-CAM180) in its highly sialylated embryonic and less glycosylated adult forms. In primary cerebellar cell cultures, N-CAM180 antibody reacts intracellularly with all types of neural cells including astrocytes, oligodendrocytes, and neurons. During cerebellar, telencephalic, and retinal development N-CAM180 is detectable by indirect immunohistology in differentiated neural cells, but, in contrast to total N-CAM, not in their proliferating precursors in the ventricular zone and primordial and early postnatal external granular layer. In monolayer culture...
European Journal of Biochemistry, 1991
We previously described the production of monoclonal antibodies against a preparation of membrane glycoproteins from human brain [Berglund et al. (1987) J. Neurochem. 48, 809-8151. One of the glycoproteins, recognized by monoclonal antibody CF3, was specifically expressed in the brain. We now report the isolation and characterization of this glycoprotein, called glycoprotein 135 (Gp135). Gpl35 was purified by means of lentil lectin affinity chromatography and immunoaffinity chromatography, using monoclonal antibody CF3, from a crude membrane extract of human brain cortex. Gp135 was shown to consist of a glycosylated single polypeptide chain with an apparent molecular mass of 135 kDa. The size of the polypeptide moiety was estimated to 11 5 kDa following N-glycanase digestion. The glycoprotein is anchored in the membrane by a glycosylphosphatidylinositol tail, as shown by phospholipase C digestion and liposome incorporation experiments. Amino acid sequence analysis of the amino terminal, and of an internal peptide obtained by V8 protease digestion of the glycoprotein, revealed a strong similarity to three previously described glycoproteins from chicken (contactin and F11) and mouse (F3) brains. These glycoproteins belong to the immunoglobulin superfamily and are implicated in cell adhesion phenomena in the developing brain. Gp135 may be the human counterpart to one or several of these glycoproteins. Cell adhesion phenomena constitute an important factor in the developing nervous system [l]. One of the first steps during brain morphogenesis is the projection of axons to their targets through a diverse and changing environment. The final result is an intricate pattern of neuronal cells of different types forming complex nets of interactions characteristic for the mature brain. The way these internal cell contacts are generated is unknown. The organization has been shown to be guided by diffusible tropic factors, molecules expressed in the extracellular matrix, and membrane glycoproteins expressed on cells [2]. The knowledge of such brain-specific glycoproteins is still limited. In the group of brain glycoproteins participating in cell adhesion, three distinct gene families seem to be involved, including (a) the calcium-dependent adhesion molecules, the cadherins [3], (b) a group of cell surface receptors, the integrins, which bind to arginine-glycine-aspartic acid (RGD) or related sequences [4, 51 and finally (c) a group of cell adhesion molecules (CAMS) which have sequences related to
Neuroscience, 1993
Neuron-glia-related cell adhesion molecule (Nr-CAM) is a recently characterized cell adhesion molecule in the family of immunoglobulin-related molecules of which the neural cell adhesion molecule, N-CAM, is the prototype. Nr-CAM shares structural properties with another member of this family (neuron-glia CAM, Ng-CAM) and both molecules exhibit homophilic and heterophilic binding propcrties. To understand better the role of such molecules in development, we have examined the sites of synthesis and expression of Nr-CAM by means of in situ hybridization and immunohistochemistry. Both methods indicated that N&AM is expressed only in the nervous system. The molecule was observed on neurons in both the peripheral and central nervous systems and on epitheliai floor plate cells in the spinal cord, but it was absent in the germinal zones. The protein was present on perikarya, but was found preferentially on axonal tracts. As observed for messenger RNAs specifying other cell adhesion molecules, messenger RNA for NC-CAM was localized in the perikarya.
The ubiquitous neural cell adhesion molecule (N-CAM)
Annals of medicine and surgery (2012), 2014
Adhesive interactions are important for cell trafficking, differentiation, function and tissue differentiation. Neural cell adhesion molecule (NCAM) is involved in a diverse range of contact-mediated interactions among neurons, astrocytes, oligodendrocytes, and myotubes. It is widely but transiently expressed in many tissues early in embryogenesis. Four main isoforms exist but there are many other variants resulting from alternative splicing and post-translational modifications. This review discusses the actions and association of N-CAM and variants, PSA CAM. L1CAM and receptor tyrosine kinase. Their interactions with the interstitial cells of Cajal - the pacemaker cells of the gut in the manifestation of gut motility disorders, expression in carcinomas and mesenchymal tumours are discussed.
The Journal of Cell Biology, 1991
The neuron-glia cell adhesion molecule (Ng-CAM) mediates both neuron-neuron and neuron-glia adhesion; it is detected on SDS-PAGE as a predominant 135-kD glycoprotein, with minor components of 80, 190, and 210 kD. We have isolated cDNA clones encoding the entire sequence of chicken Ng-CAM. The predicted extracellular region includes six immunoglobulin-like domains followed by five fibronectin-type III repeats, structural features that are characteristic of several neural CAMs of the N-CAM superfamily. The amino acid sequence of chicken Ng-CAM is most similar to that of mouse L1 but the overall identity is only 40% and Ng-CAM contains a short fibronectin-like segment with an RGD sequence that has no counterpart in L1. These findings suggest that Ng-CAM and L1 may not be equivalent molecules in chicken and mouse.
Oligodendrocyte cell adhesion molecules are related to neural cell adhesion molecule (N-CAM)
The Journal of Neuroscience, 1986
The glycoproteins responsible for calcium-dependent oligodendrocyte aggregation were purified and characterized. Using detergent extraction, lentil-lectin-Sepharose 4B aflinity chromatography, and preparative gel electrophoresis, 3 proteins were purified to apparent homogeneity, with relative M,s of 120,000, 140,000, and 180,000. The aggregation assay showed that all 3 proteins had the ability to block antibody-mediated inhibition of oligodendrocyte aggregation. The 120,000 protein was the most active of the three. Antisera were raised in rabbits to these 3 individual proteins. Western blot analyses showed that all three antisera recognized 120,000, 140,000, and 180,000 proteins, which indicated that the proteins were related. Westernblot analyses of cultured oligodendrocytes and purified rat myelin showed only the 120,000 protein. Immunoprecipitation of iodinated membrane proteins of cultured oligodendrocytes also indicated the presence of only the 120,000 iVf, protein. Deglycosylation of the 120,000 protein by N-glycanase resulted in a 110,000 protein. The immunoblot pattern suggested some similarities between oligodendrocyte adhesion molecules and the neural cell adhesion molecule (N-CAM). Therefore, the 120,000, 140,000, and 180,000 ikl, proteins were compared to N-CAM by Western-blot analysis, immunofluorescence staining, and by immunoprecipitation. The results suggest that oligodendrocytes contain a 120,000 membrane glycoprotein that is related to N-CAM.
C6 glioma cells express modified neural-cell adhesion molecule-like glycoproteins
Brain Research, 1987
We have studied the expression of neural-cell adhesion molecule (N-CAM)-Iike glycoproteins in a C6 glioma cell line. We found that: (a) C6 cells express N-CAM-like proteins on the cell surface, (b) the N-CAM-like proteins in C6 ceils have apparent molecular weights of 130,000 and 150,000 kDa which are not seen in rodent brain and (c) deglycosylation of (26 N-CAMs suggest that the modifications are both in the carbohydrate and protein parts of the N-CAM. The expression of modified N-CAM glycoproteins is of interest in relation to the regulation of N-CAM expression.
Differential contributions of Ng-CAM and N-CAM to cell adhesion in different neural regions
The Journal of Cell Biology, 1986
Individual neurons can express both the neural cell adhesion molecule (N-CAM) and the neuron-glia cell adhesion molecule (Ng-CAM) at their cell surfaces. To determine how the functions of the two molecules may be differentially controlled, we have used specific antibodies to each cell adhesion molecule (CAM) to perturb its function, first in brain membrane vesicle aggregation and then in tissue culture assays testing the fasciculation of neurite outgrowths from cultured dorsal root ganglia, the migration of granule cells in cerebellar explants, and the formation of histological layers in the developing retina. Our strategy was
Proceedings of the National Academy of Sciences, 1987
The neural cell adhesion molecule, N-CAM, is expressed as at least three polypeptide chains (Id, sd, and ssd chains) specified by a single gene and derived by alternative splicing and polyadenylylation-site selection during RNA processing. We describe here the characterization of seven overlapping genomic phage clones reactive with N-CAM cDNA, indicating that the chicken N-CAM gene is more than 50 kilobases long. Analysis of the gene shows that there are at least 19 exons and that the coding sequences for the Id, sd, and ssd chains are assembled from 18, 17, and 15 exons, respectively. The first 14 exons appear to be common to all three chains and encode the amino-terminal portion of N-CAM, which contains five tandem homologous repeats resembling those seen in the immunoglobulin gene superfamily. In contrast to other genes containing such domains, each of these segments in N-CAM is specified by two exons. The carboxyl-terminal portion of each N-CAM chain is different as a result of the alternative use of exons. A single exon encodes the carboxylterminal 26 amino acids of the ssd chain and the 3' untranslated region of its mRNA, ending with a poly(A)-addition site. Two exons encode the transmembrane and cytoplasmic sequences common to the Id and sd chains, and another exon encodes the additional 261 amino acids found in the cytoplasmic domain of the Id chain. The carboxyl-terminal 21 amino acids common to the Id and sd chains and the 3' untranslated region common to their mRNAs are encoded by a single large exon of 3475 base pairs that ends with a second poly(A)-addition site. Sequences from the 13-kilobase intron that separates the exons encoding the amino-terminal and carboxyl-terminal regions of the molecule hybridize to a 2-kilobase poly(A)+ RNA transcript of unknown identity. This description of the chicken N-CAM gene provides a basis for determining the mechanisms that regulate the differential expression of the N-CAM polypeptide chains during development.