Phosphorylation of the glycoprotein hormone alpha-subunit secreted by human tumor cell lines.
The synthesis of ectopic proteins by tumors is thought to result from derepression of normally silent genes. One approach to a better understanding of this phenomenon is to characterize the physicochemical properties of the ectopic products, comparing them to their normal counterparts. In the following communication, evidence will be presented to indicate that the glycoprotein hormone alpha-subunits secreted by a number of human tumor cell lines are phosphorylated. This novel covalent modification occurs in cell lines derived from both trophoblastic (JAR, JEG) and nontrophoblastic (HeLa, ChaGo) tumors. A choriocarcinoma cell line (JAR), which secretes both hCG-alpha and hCG-beta, phosphorylates only the alpha-subunit.
D001345:Autoradiography; D002460:Cell Line; D015292:Glycoprotein Hormones, alpha Subunit; D006023:Glycoproteins / Q000032:analysis*; D006367:HeLa Cells / Q000032:analysis; D006729:Hormones, Ectopic / Q000032:analysis*; D006801:Humans; D009369:Neoplasms / Q000378:metabolism*; D010446:Peptide Fragments / Q000032:analysis; D010750:Phosphoproteins / Q000032:analysis*; D010766:Phosphorylation; D010908:Pituitary Hormones, Anterior / Q000032:analysis
D015292:Glycoprotein Hormones, alpha Subunit; D006023:Glycoproteins; D006729:Hormones, Ectopic; D010446:Peptide Fragments; D010750:Phosphoproteins; D010908:Pituitary Hormones, Anterior