The v-rel oncogene product is complexed to a 40-kDa phosphoprotein in transformed lymphoid cells.
The transforming protein encoded by the v-rel oncogene of avian reticuloendotheliosis virus (REV-T) is a very low copy number molecule in the cytosol of transformed cells. Analysis of cytosolic extracts from a REV-T-transformed lymphoid cell line by gel filtration on Sephacryl S-300 indicated that most of the v-rel oncogene product, pp59v-rel, eluted with an apparent molecular mass of 400 kDa. The size of this complex was confirmed by analysis on a fast-protein liquid chromatography gel filtration column. A 40-kDa cellular protein copurified with pp59v-rel on sequential gel filtration on Sephacryl S-200 and immunoaffinity chromatography with a monoclonal antibody directed against pp59v-rel. The 40-kDa cellular protein could also be immunoprecipitated together with pp59v-rel from cell extracts of [35S]methionine-labeled cells, suggesting that pp59v-rel is complexed with the 40-kDa protein in transformed lymphoid cells. Both the 59- and 40-kDa proteins were phosphorylated when the highly purified preparation containing pp59v-rel was incubated with [gamma-32P]ATP and 10 mM MgCl2 in vitro. The identity of the kinase in the highly purified preparation containing pp59v-rel, however, is unknown. Immune complexes recovered from extracts of REV-T-transformed lymphoid cells labeled with [32P]orthophosphate also contained the 59- and 40-kDa phosphoproteins. These observations suggest that pp59v-rel is complexed with a 40-kDa cellular phosphoprotein to form a 400-kDa heteropolymer in the cytoplasm of transformed lymphoid cells.
Tung
H Y
HY
Clayton Foundation Biochemical Institute, University of Texas, Austin 78712.
Bargmann
W J
WJ
Lim
M Y
MY
Bose
H R
HR
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002472:Cell Transformation, Viral; D008214:Lymphocytes; D046911:Macromolecular Substances; D008970:Molecular Weight; D009856:Oncogene Proteins, Viral / Q000378:metabolism*; D009857:Oncogenes; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D046911:Macromolecular Substances; D009856:Oncogene Proteins, Viral; D010750:Phosphoproteins; D011494:Protein Kinases