title: Identification of a form of the avian erythroblastosis virus erb-B gene product at the cell surface.
abstract: Avian erythroblastosis virus (AEV) induces both erythroblastosis and fibrosarcoma in chickens. The viral oncogene responsible for these diseases, erb, is divided into two regions, erb-A and erb-B, although recent evidence suggests that it is primarily the erb-B gene product that is responsible for the transforming activity. The erb-B gene product has been reported previously to be a membrane glycoprotein of 68,000 molecular weight (MW), gp68erb -B. However, we show here that gp68erb -B is an intracellular precursor which is modified further to a 74,000 MW protein, gp74erb -B. By the criteria of resistance to digestion with endoglycosidase H, subcellular fractionation and inhibition of biosynthesis by the ionophore monensin, gp74erb -B appears to be located at the cell surface. Recently, a comparison of the erb-B sequence with that of the epidermal growth factor (EGF) receptor has shown that these two genes are highly homologous, and that erb-B appears to represent a truncated form of this growth factor. In light of these data the identification of gp74erb -B at the plasma membrane suggests that this may be the functionally important form of the erb-B gene product.
mesh_terms: D001355:Alpharetrovirus / Q000235:genetics*; D000818:Animals; D001354:Avian Leukosis Virus / Q000235:genetics*; D002460:Cell Line; D002462:Cell Membrane / Q000032:analysis; D002471:Cell Transformation, Neoplastic; D005796:Genes; D005814:Genes, Viral; D006023:Glycoproteins / Q000235:genetics* / Q000302:isolation & purification; D007700:Kinetics; D008565:Membrane Proteins / Q000235:genetics* / Q000302:isolation & purification; D008970:Molecular Weight; D009857:Oncogenes; D011494:Protein Kinases / Q000235:genetics; D011505:Protein-Tyrosine Kinases; D051381:Rats; D014764:Viral Proteins / Q000235:genetics
chemical_list: D006023:Glycoproteins; D008565:Membrane Proteins; D014764:Viral Proteins; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases