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: This article briefly summarizes the author's contribution to the study of cell surface glycoproteins. At first, much effort was devoted to developing analytical methods, especially exoglycosidases and endoglycosidases. An endo-beta-N-acetylglucosaminidase found in Streptococcus pneumoniae was the first example of an endoglycosidase acting on glycoproteins. A combination of radioactive labeling, glycosidase digestion and lectin affinity chromatography enabled the characterization of carbohydrate moieties of cell surface glycoproteins derived from cultured cells. Application of the method to teratocarcinoma stem cells and preimplantation mouse embryos led to the discovery of marked changes in the carbohydrate moieties of cell surface glycoproteins during embryogenesis. Combining biochemical and immunohistochemical methods, an overall picture was obtained for carbohydrate changes in early embryogenesis of the mouse, and molecular biological approaches have been adopted to determine their biological significance. Furthermore, some core proteins carrying developmentally regulated carbohydrate markers were found and characterized by molecular cloning. One example of such a protein is embigin, which enhances integrin-mediated cell-substratum adhesion and established the existence of a new group in the immunoglobulin superfamily. Carbohydrate immunochemical markers useful in the analysis of mouse embryogenesis were also found to be effective in the classification of human carcinomas with respect to metastatic potential.Nagoya journal of medical science 01/1995; 57(3-4):95-108.
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ABSTRACT: Embryoid bodies (EB) derived from teratocarcinoma OTT6050 are a useful model for the study of early embryogenesis and tumorigenesis and are found in two forms: cystic and simple. After injection of cystic EB intraperitoneally into isogenic 129/Sv mice, their growth and the expression of laminin (LAM) and fibronectin (FN) were studied at 5, 7 and 9 days post-injection. LAM was highly expressed on the internal face of endodermal and on some internal cells in cystic type EB and in both endodermal cell faces in simple EB. Only slight FN expression was observed in cystic and simple EB. Extracellular matrix proteins can be studied in this model.Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 01/1991; 418(6):509-514. · 2.68 Impact Factor
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ABSTRACT: The expression of two carbohydrate markers--namely, 4C9 antigen, which is an Lex antigen, and the Dolichos biflorus agglutinin (DBA) binding site, which is an N-acetylgalactosamine marker--was examined histochemically in tumors and adjacent nontumorous tissues of 102 cases of human lung carcinomas. In nontumorous tissues, the DBA binding site was expressed more frequently than 4C9 antigen, and the DBA binding site had a tendency to be expressed more significantly than in tumor cells. Adenocarcinomas and well-differentiated tumors had a tendency to more cell surface staining. Patients with tumors that expressed DBA binding sites but not 4C9 antigen (4C9-, DBA+) had fewer metastasis and significantly better prognoses than patients with tumors of other carbohydrate profiles. Better prognosis of patients with 4C9-, DBA+ tumors was observed in those with blood group A antigen and those without it, and the better prognosis also was observed in patients with Stage I and IIIA disease.Cancer 05/1992; 69(8):2084-90. · 5.20 Impact Factor