Biosynthesis of the epidermal growth factor receptor in human epidermoid carcinoma-derived A431 cells.
Using human-specific antibody reagents, we have examined the biosynthesis of the epidermal growth factor receptor in human epidermoid carcinoma-derived A431 cells. Four Mr species (Mr = 70,000, 95,000, 135,000, and 145,000) are detected when cells are subjected to a brief pulse of L-[35S]methionine; an Mr = 165,000 species is detected after 45-60 min of exposure of cells to radiolabel. In pulse-chase experiments, the four lower Mr species appear to bear a precursor relation to the Mr = 165,000 protein. The molecule acquires N-linked oligosaccharide cotranslationally, and two of the species (Mr = 95,000 and 145,000) are susceptible to digestion with endo-beta-N-acetylglucosaminidase H. The Mr = 145,000 and Mr = 165,000 proteins, which become labeled with 125I-epidermal growth factor after treatment of intact cells with a bifunctional cross-linking reagent, are phosphorylated at serine and threonine on identical tryptic peptides.
D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D066246:ErbB Receptors; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D014357:Trypsin / Q000378:metabolism
D010446:Peptide Fragments; D011956:Receptors, Cell Surface; D066246:ErbB Receptors; D014357:Trypsin