Basement membrane glycoprotein laminin is an agglutinin.
ABSTRACT Laminin was purified to homogeneity from the extracellular matrix and soluble fraction of teratocarcinoma OTT6050 and also partially purified from the ascitic fluid of the mice carrying the teratocarcinoma. These laminin preparations were found to agglutinate trypsinized, glutaraldehyde-fixed rabbit erythrocytes. The hemagglutinating activity was inhibited by porcine gastric mucin, which invertase and mannan were not inhibitory. Heparin and heparan sulfate also inhibited the hemagglutination. Simple saccharides such as D-galactose, N-acetyl D-glucosamine, and N-acetyl D-galactosamine were not inhibitory, but D-glucosamine and D-galactosamine were. The hemagglutinating activity required Ca2+ and was dependent upon temperature. These results raised the possibility that laminin functions also in cell-cell interactions such as cell-cell adhesion. In addition, we report that laminin synthesized by the teratocarcinoma did not carry the large carbohydrate chain characteristic of early embryonic cells.
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ABSTRACT: Nagoya Journal of Medical Science, 57(3-4), 1994, p. 95-108
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ABSTRACT: MDW4, a wheat germ agglutinin-resistant nonmetastatic mutant of the highly metastatic murine tumor cell line called MDAY-D2 has previously been shown to attach to fibronectin and type IV collagen, whereas MDAY-D2 and phenotypic revertants of MDW4 attached poorly to these substrates. The increased adhesiveness of the mutant cells appeared to be closely related to a lesion in cell surface carbohydrate structures. In an effort to identify the carbohydrates involved in cell attachment, glycopeptides isolated from mutant and wild-type cells as well as from purified glycoproteins were tested for their ability to inhibit the attachment of MDW4 cells to plastic surfaces coated with fibronectin, laminin, or type IV collagen. The addition of mannose-terminating glycopeptide to the adhesion assay inhibited MDW4 cell attachment to type IV collagen. In contrast, a sialylated poly N-acetyllactosamine-containing glycopeptide, isolated from wheat germ agglutinin-sensitive MDAY-D2 cells but absent in MDW4 cells, inhibited MDW4 attachment to laminin. None of the glycopeptides used in this study inhibited attachment of MDW4 cells to fibronectin-coated plastic. Peptide N-glycosidase treatment of the cells to remove surface asparagine-linked oligosaccharides inhibited MDW4 adhesion to type IV collagen, but not to laminin, and the same treatment of the wheat germ agglutinin-sensitive cells enhanced attachment to laminin. Tumor cell attachment to, and detachment from, the sublaminal matrix protein laminin and type IV collagen are thought to be important events in the metastatic process. Our results indicate that tumor cell attachment to these proteins may be partially modulated by the expression of specific oligosaccharide structures associated with the cell surface.The Journal of Cell Biology 11/1984; 99(4 Pt 1):1416-23. · 9.69 Impact Factor
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ABSTRACT: Previous studies of the agglutination of erythrocytes by the basement membrane glycoprotein laminin have suggested that laminin binds to gangliosides [Kennedy, D.W., Rohrbach, D.H., Martin, G.R., Momoi, T. & Yamada, K.M. (1983) J. Cell. Physiol. 114, 257-262]. Based on the following evidence, however, we find that laminin binds specifically to sulfatides, not gangliosides. Monogalactosyl sulfatides, purified from sheep erythrocytes with a yield of 4.3 mg/kg of packed cells, bound laminin with high affinity as did authentic bovine brain sulfatide (galactosylceramide-I3-sulfate). The binding activity of these lipids and of total erythrocyte lipids was stable to alkali and neuraminidase treatment but labile to dilute acid under conditions that destroy sulfatides but not gangliosides. Of various glycolipid and phospholipid standards tested, only sulfatides bound laminin with high affinity. Sulfatide binding and agglutinating activities of proteolytic fragments of laminin indicated that the globular end regions of the 200-kDa subunits are required for both activities. Thus, monogalactosylsulfatides, and possibly other more complex sulfated glycolipids, are probably involved in the agglutination of erythrocytes. These results also suggest a physiological function of sulfatides in cell adhesion. The agglutination of erythrocytes by fibronectin is also inhibited by gangliosides [Yamada, K.M., Kennedy, D.W., Grotendorst, G.R. & Momoi, T. (1981) J. Cell. Physiol. 109, 343-351]. Fibronectin, however, did not bind to sulfatides with high affinity but rather bound with low affinity to all anionic lipids tested, including phospholipids, gangliosides, and sulfatides.Proceedings of the National Academy of Sciences 03/1985; 82(5):1306-10. DOI:10.1073/pnas.82.5.1306 · 9.81 Impact Factor