Transformation by v-sis occurs by an internal autoactivation mechanism.
Transformation by the v-sis oncogene appears to require an interaction of its protein product, p28v-sis, with the receptor for the platelet-derived growth factor (PDGF). However, this interaction may not occur at the cell surface as predicted by the autocrine hypothesis because phenotypic transformation was not reversed by incubation of SSV-NRK cells with antisera to PDGF and because morphological transformation did not occur when nontransformed NRK cells were cultured continuously with p28v-sis. A mutant of the wild-type v-sis gene was constructed that encodes a v-sis protein targeted for retention within the endoplasmic reticulum and Golgi. NRK cells expressing the mutant v-sis gene did not secrete any detectable v-sis protein but were as fully transformed as wild-type v-sis transfectants. The results support a mechanism of transformation by v-sis in which internal activation of the PDGF receptor occurs before expression of either p28v-sis or the PDGF receptor at the cell surface.
Bejcek
B E
BE
Department of Medicine, Jewish Hospital, Washington University Medical Center, St. Louis, MO 63110.
Li
D Y
DY
Deuel
T F
TF
D000595:Amino Acid Sequence; D001483:Base Sequence; D002461:Cell Line, Transformed; D008969:Molecular Sequence Data; D009154:Mutation; D020575:Oncogene Proteins v-sis; D010982:Platelet-Derived Growth Factor / Q000096:biosynthesis*; D011956:Receptors, Cell Surface; D017479:Receptors, Platelet-Derived Growth Factor; D012191:Retroviridae Proteins / Q000235:genetics / Q000502:physiology*; D012842:Sarcoma Virus, Woolly Monkey; D014170:Transformation, Genetic
D020575:Oncogene Proteins v-sis; D010982:Platelet-Derived Growth Factor; D011956:Receptors, Cell Surface; D012191:Retroviridae Proteins; D017479:Receptors, Platelet-Derived Growth Factor