Autocrine stimulation by the v-sis gene product requires a ligand-receptor interaction at the cell surface.
Autocrine expression of a growth factor and its receptor in the same cell raises the possibility of an intracellular receptor-ligand interaction within the cell, in addition to a receptor-ligand interaction at the cell surface. We have constructed a NIH3T3 cell line which contains the v-sis gene under the inducible control of the Drosophila melanogaster hsp70 promoter. Expression of both v-sis RNA and protein is rapidly induced by a short period of heat-shock. We have analyzed the cellular site of interaction between the v-sis protein and the platelet-derived growth factor receptor in these cells. Autophosphorylation of the PDGF receptor and induction of the c-fos gene were found to occur at 45 and 50 min, respectively, after heat-induced synthesis of the v-sis protein. Monensin treatment of the heat-induced cells prevented autophosphorylation of the mature PDGF receptor and also prevented subsequent induction of c-fos. Autophosphorylation of the PDGF receptor and c-fos induction were also prevented by the addition of suramin to the medium. These results demonstrate that autocrine stimulation, as monitored by c-fos induction and by PDGF receptor autophosphorylation, requires an interaction between the v-sis protein and the PDGF receptor that occurs at the cell surface, rather than an intracellular location.
Hannink
M
M
Department of Chemistry, University of California, San Diego, La Jolla 92093.
Donoghue
D J
DJ
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D003001:Cloning, Molecular; D004331:Drosophila melanogaster; D005786:Gene Expression Regulation; D006358:Hot Temperature; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008985:Monensin / Q000494:pharmacology; D009693:Nucleic Acid Hybridization; D020575:Oncogene Proteins v-sis; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016760:Proto-Oncogene Proteins c-fos; D012313:RNA / Q000235:genetics; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017479:Receptors, Platelet-Derived Growth Factor; D012191:Retroviridae Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D013498:Suramin / Q000494:pharmacology
D008024:Ligands; D020575:Oncogene Proteins v-sis; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D011956:Receptors, Cell Surface; D012191:Retroviridae Proteins; D013498:Suramin; D012313:RNA; D008985:Monensin; D017479:Receptors, Platelet-Derived Growth Factor