The E5 oncoprotein of bovine papillomavirus binds to a 16 kd cellular protein.
The E5 oncoprotein of bovine papillomavirus type 1 is the smallest known viral transforming protein. It is a 44 amino acid polypeptide asymmetrically oriented in Golgi and plasma membranes which appears to modify (either directly or indirectly) the internalization and phosphorylation of at least two growth factor receptors: EGF and CSF-1. To identify cellular proteins associated with E5, we have constructed two E5 fusion proteins, each of which contains a well-characterized epitope at the E5 amino terminus. These E5-epitope fusion proteins are biologically active, localize normally to cellular membranes and form dimers. Both monoclonal and polyclonal antibodies against the inserted epitopes specifically co-precipitate E5 and an associated 16 kd cellular protein. A transformation-defective E5 mutant containing a substitution within the hydrophobic portion of E5 is defective in its ability to bind the 16 kd protein. These findings suggest a role for E5/16 kd binding in the process of cellular transformation.
Laboratory of Tumor Virus Biology, National Cancer Institute, Bethesda, MD 20892.
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D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D003545:Cysteine / Q000378:metabolism; D000939:Epitopes / Q000235:genetics; D015870:Gene Expression; D005822:Genetic Vectors; D006056:Golgi Apparatus / Q000378:metabolism; D000882:Haplorhini; D007163:Immunosorbent Techniques; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D027383:Papillomaviridae / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D010957:Plasmids; D011506:Proteins / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D000939:Epitopes; D046911:Macromolecular Substances; D009856:Oncogene Proteins, Viral; D010710:Phosphates; D011506:Proteins; D011993:Recombinant Fusion Proteins; C054304:oncogene protein E5, Bovine papillomavirus type 1; D003545:Cysteine