A novel 39-kilodalton membrane protein binds GTP in polyomavirus-transformed cells.
To investigate the possible involvement of GTP-binding proteins in transformation by the DNA tumor virus polyomavirus, the GTP-binding activities of Ras-like proteins and G protein alpha subunit proteins were examined in polyomavirus-transformed cells. No differences in the degrees or patterns of expression of Ras-like proteins were observed. However, a 39-kDa protein specifically bound GTP in membranes from polyomavirus-transformed cells. This protein was not seen in nontransformed or lytically infected cells or in phenotypically normal revertants of polyomavirus-transformed cells. It reappeared, however, in spontaneous retransformants derived from the revertants. The 39-kDa protein was not found stably associated with polyomavirus T antigens, nor was it phosphorylated on tyrosine. The 39-kDa protein was not recognized by an antiserum specific for members of the Gi alpha subfamily of G proteins or by antisera against all other known GTP-binding proteins of similar molecular mass. These results suggest that this novel 39-kDa GTP-binding membrane protein is observed as part of a long-term response that accompanies stable transformation by the virus.
Bauer
P H
PH
Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Benjamin
T L
TL
D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000378:metabolism; D002472:Cell Transformation, Viral; D019204:GTP-Binding Proteins / Q000502:physiology*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008970:Molecular Weight; D011120:Polyomavirus / Q000235:genetics*; D051381:Rats
D000952:Antigens, Polyomavirus Transforming; D008565:Membrane Proteins; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins