期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1979
卷号：76
期号：7
页码：3343-3347
DOI：10.1073/pnas.76.7.3343
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We have investigated the role of the carbohydrate moiety in the biological activity of fibronectin in vitro by using tunicamycin to inhibit the glycosylation of this glycoprotein. Tunicamycin is a glucosamine-containing antibiotic that specifically inhibits glycosylation of protein asparaginyl residues mediated by dolichol pyrophosphate. Fibronectin synthesized in the presence of 0.5 microgram of tunicamycin per ml was not glycosylated, as determined by amino sugar analysis, lack of incorporation of [14C]glucosamine and [3H]mannose, and concanavalin A binding studies. Nonglycosylated fibronectin that was isolated from chicken embryo fibroblasts and added to transformed cells in vitro was as effective as the glycosylated protein in promoting a more normal fibroblastic phenotype, including cell flattening, elongation of cell processes, and parallel alignment of cells. The nonglycosylated protein was also as effective as the glycosylated species in mediating cell attachment to collagen and spreading on plastic, as well as in agglutination of formalin-fixed sheep erythrocytes. The nonglycosylated protein was twice as sensitive as the glycosylated protein to proteolytic hydrolysis in vitro as had been suggested by previous studies with intact cells [Olden, K., Pratt, R.M. & Yamada, K.M. (1978) Cell 13, 461-473]. We conclude that the carbohydrate moiety of fibronectin is not required for the mediation of a number of biological activities characteristic of this glycoprotein.
