N-CAM

Daumen mutter, /, Mack.) -thumb nut, -rad, n. cam wheel, -schraube, /. thumb screw. -Welle, /. camshaft,... 

NAP-I, NAP-2 Neutrophilactivating peptides -1 and -2 NBT Nitro-blue tetrazolium NCI Non-collagen 1 N-CAM Neural cell adhesion molecule... 

Fig. 4.6(a) Migration of LHRH neurocrine cells prenatal transportation along the track of extra-bulbar VN axons (caudal branch). CB, cribriform plate FB, forebrain cell types, TAG-1, transient axonal surface glycoprotein and N-CAM, neural cell adhesion molecule (from Yoshida et al, 1995). 

Adhesion molecules such as LI, neural cell adhesion molecule (N-CAM) and N-cadherin promote axonal regeneration by homophilic interactions between axons and Schwann cell surfaces (see Ch. 7). The expression of p75 (low affinity NGF receptor, Ch. 27) is also increased at the Schwann cell surface after injury. Extracellular matrix molecules, such as tenascin and proteoglycans, increase the regenerative potential of damaged peripheral nerves by binding to integrins on the axonal surface. 

One of the most widely studied molecules from this group of adhesion proteins is N-CAM (B4). N-CAM contains type III fibronectin domains in addition to the immunoglobulin domains. N-CAM also forms covalent associations with poly-sialic acid. This modified form of N-CAM may exert a repulsive force through its high negative surface charge. This, in turn, would lessen cell adhesion and allow invasion. 

The cytoskeleton is found near the axonal membrane and consists of microfilaments linked internally to microtubules and the plasma membrane by a network of filamentous protein that includes the brain-specific protein fodrin. This protein forms attachment sites for integral membrane proteins either by means of the neuronal cell adhesion molecule (N-CAM) or indirectly by means of a specific protein called ankyrin in the case of the sodium channels. This may provide a means whereby the sodium channels are concentrated in the region of the nodes of Ranvier. Thus the cortical cytoskeleton plays a vital role in neuronal function by acting as an attachment site for various receptors and ion channels, but also for s)maptic vesicles at nerve terminals, thereby providing a mechanism for concentrating the vesicles prior to the release of the neurotransmitter. 

The transition from mesenchyme to epithelium involves biochemical changes in the cells and the extracellular matrix, N-CAM expression on cell surfaces disappears, replaced by L-CAM (uvomorulin). Vimentin, a characteristic cytoskeletal component of mesenchyme, disappears, and cytokeratin, characteristic of epithelia, appears. There is a decrease in collagen I extracellularly and an increase in the basement membrane components laminin and collagen IV. 

Vawter MP, Howard AL, Hyde TM, Kleinman JE, Freed WJ. 1999. Alterations of hippocampal secreted N-CAM in bipolar disorder and synaptophysin in schizophrenia. Mol Psychiatry 4 467-475. 

CAM, is the name for a cell adhesion molecule on the surface of animal cells. N-CAM is located on neurons. 

In a 500-ml. three-necked flask equipped with a mechanical stirrer, a dropping funnel, and a reflux condenser fitted with a potassium hydroxide drying tube are placed 7.0 g. (0.069 mole) of triethylamine (Note 1) and a solution of 3.15 g. (0.075 mole) of diazomethane in 200 ml. of ether (Note 2). The flask is cooled in an ice bath, and a solution of 13.0 g. (0.052 mole) of n-cam-phor-lO-sulfonyl chloride (Note 3) in 75 ml. of anhydrous ether is added dropwise over a period of 1 hour. Triethylamine hydrochloride slowly precipitates. The reaction mixture is stirred for an additional 30 minutes and then concentrated to ca. 150 ml. under reduced pressure (water aspirator) with continued stirring to remove the excess of diazomethane. The mixture is Altered under reduced pressure the precipitate is washed with 50 ml. of... 

The ring-opening oxidation with nitric acid of 3,7i-dibromocamphor (246) has been re-examined by Brienne and Jacques, who have shown that treatment of the r-bromocamphoric acid (247 R = H) thus obtained with one equivalent of alkali gives the unusual trans-fused y-lactone [(248 R = H), the trans-n-cam-phanic acid of the 19th century]. The structure already derives from the fact that... 

Comparisons between monolayers and similar layers on solids is of interest, both academically and for applications. The academic one is that the two layers are complementary and that it is interesting to find out what structural similarities and dissimileulties exist. Complementcirity is expressed by the fact that for the Langmuir monolayer n cam be measured, whereas for layers on, say mica, the disjoining pressure cam be estimated. For one of the mamy illustrations see K... 

Nouwen EJ, Dauwe S, van der Blest I, De Broe ME. Stage- and segment-specific expression of cell-adhesion molecules N-CAM, A-CAM, and E-CAM in the kidney. Kidney Int 1993 44 147-158. 

Cellular adhesion is performed by a large set of transmembrane proteins integrins, cadherins, selectins and Ig superfamily members (Ig-N-Cam, ICAM. ..). 

Doherty P, Cohen J, Walsh FS. 1990. Neurite outgrowth in response to transfected N-CAM changes during development and is modulated by polysialic acid. Neuron 5 209-219. 

Hoffman S, Friedlander DR, Chuong CM, Grumet M, Edelman GM. 1986. Differential contributions of Ng-CAM and N-CAM to cell adhesion in different neural regions. J Cell Biol 103 145-158. 

Martini R, Schachner M. 1988. Immunoelectron microscopic localization of neural cell adhesion molecules (LI, N-CAM, and myelin-associated glycoprotein) in regenerating adult mouse sciatic nerve. J CeU Biol 106 1735-1746. 

Persohn E, Schachner M. 1987. Immunoelectron microscopic localization of the neural cell adhesion molecules LI and N-CAM during postnatal development of the mouse cerebellum. J Cell Biol 105 569-576. 

Effects of oligosaccharides on the biological functions of proteins (15 examples). The capacity for homophilic binding of the neural cell adhesion molecule (N-CAM, Section 12.5.3) is modulated by the extension of its polysialic chains. The binding of a highly specific heparin pentasaccharide sequence to the protein antithrombin III converts it to a potent anticoagulant (Section 17.3). 

Cell adhesion plays a major role in the embryonic development of the nervous system. Rather than a great number of adhesion molecules being involved, it is now believed that there are only a small group of different specificities and that the variety of phenomena observed is based on the coordination of their expression with cytoplasmic events. The N-CAM molecules are the best known (Cunningham et al. 1987). 

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