title: Fibronectin from chicken embryo fibroblasts contains covalently bound phosphate.
abstract: Fibronectin isolated from cultures of chicken embryo fibroblasts (CEF) contains phosphorus linked to serine and threonine by monoester bonds. Normal and Rous sarcoma virus (RSV)-transformed cells were incubated with [32P]orthophosphate, and fibronectin was isolated from the cell surfaces and conditioned media. 32P was stably associated with fibronectin during immunoprecipitation, SDS-polyacrylamide gel electrophoresis, phospholipid solvent extraction, and hot acid but not alkaline treatment. After a limited acid hydrolysis of fibronectin, both phosphoserine and phosphothreonine were found. The specific radioactivity of the 32P-labeled fibronectin from the conditioned medium of normal CEF was higher than that from the cultures of transformed CEF.
mesh_terms: D000818:Animals; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D002642:Chick Embryo; D046508:Culture Techniques; D005347:Fibroblasts / Q000032:analysis*; D006023:Glycoproteins / Q000032:analysis*; D008970:Molecular Weight; D010750:Phosphoproteins / Q000032:analysis*; D011487:Protein Conformation
chemical_list: D006023:Glycoproteins; D010750:Phosphoproteins