Eight day (8-d CEF) and 16 day old chick embryo fibroblasts (16-d CEF) obtained after a mild trypsin treatment (50 micrograms/ml in Ca2+ and Mg2+-free PBS, plus 10 mM EDTA) for 10 min at 37 degrees C present the same number of fibronectin (FN) binding sites at their surface (approximately 550,000 sites per cell) with a Kd approximately equal to 1.40 microM in both cases. Furthermore, FN interacted with high molecular weight plasma membrane proteins (150,000 and 125,000) insensitive to trypsin treatment. Both 8-d and 16-d CEF adhered and spread to the same extent on a fibronectin coated substratum (80% of the CEF adhered in 60 min). In contrast, 8-d and 16-d CEF behaved differently towards laminin (LM). 8-d CEF exhibited approximately 5500 binding sites per cell with a Kd of 1.5 nM (Codogno P., Doyennette, M.-A. and Aubery M., 1987, Experimental Cell Research, 169, 478-489.) and were highly sensitive to trypsin treatment, whereas 16-d CEF do not express cell surface binding sites for laminin. Differences were also observed in the adhesive capacities of 8-d and 16-d CEF on LM substrata: 8-d CEF adhered and spread on LM in a very specific manner (60% of the cells adhere in 60 min) and 16-d CEF did not adhere to LM even after long periods of incubation exceeding 360 min.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.