Tyrosine 807 of the v-Fms oncogene product controls cell morphology and association with p120RasGAP

• Published in: Journal of Virology 1995-10, Vol.69 (10), p.6010-6020
• Main Authors: Trouliaris, S. (Justus-Liebig-Universitat Giessen, Giessen, Germany.), Smola, U, Chang, J.H, Parsons, S.J, Niemann, H, Tamura, T
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Amino Acid Sequence; Animals; CARCINOGENOS; Cell Transformation, Neoplastic; CITOLOGIA; CYTOLOGIE; DNA Replication; ESTRUCTURA CELULAR; FIBROBLASTE; FIBROBLASTOS; FOSFORILACION; GENE; GENES; Genes, fms; GLICOPROTEINAS; GLOBULINAS; GLOBULINE; Glutathione Transferase - biosynthesis; GLYCOPROTEINE; GTPase-Activating Proteins; Kinetics; Mice; MUTACION; MUTACION INDUCIDA; MUTATION; MUTATION PROVOQUEE; NEOPLASMAS; NEOPLASME; Oncogene Protein gp140(v-fms) - biosynthesis; Oncogene Protein gp140(v-fms) - isolation & purification; Oncogene Protein gp140(v-fms) - metabolism; Oncogenes; Phenylalanine; PHOSPHORYLATION; Plasmids; Point Mutation; Protein-Tyrosine Kinases - metabolism; PROTEINA QUINASA; PROTEINAS AGLUTINANTES; PROTEINE DE LIAISON; PROTEINE KINASE; Proteins - isolation & purification; Proteins - metabolism; ras GTPase-Activating Proteins; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - isolation & purification; Recombinant Fusion Proteins - metabolism; RETROVIRIDAE; Sarcoma Viruses, Feline - genetics; Sarcoma Viruses, Feline - physiology; STRUCTURE CELLULAIRE; SUBSTANCE CANCERIGENE; Thymidine - metabolism; TIROSINA; Transfection; TYROSINE
• ISSN: 0022-538X; 1098-5514
• DOI: 10.1128/jvi.69.10.6010-6020.1995

Expression of the v-fms oncogene of feline sarcoma virus in fibroblasts causes surface exposure of an activated receptor tyrosine kinase, v-Fms, that is autophosphorylated at multiple sites within its cytoplasmic domain. Cellular proteins interacting with this part of v-Fms modulate the mitogenic activity and morphology of the cells. We show here that the tyrosine residue in position 807 (Y-807) of the v-Fms molecule constitutes a major autophosphorylation site. The replacement of this residue by phenylalanine (Y807F mutation) allowed us to functionally dissect v-Fms-specific mitogenic and morphogenic cascades. Cells expressing the mutant v-Fms molecule resembled wild-type (wt) v-Fms-transformed (wt-v-Fms) cells in terms of [3H]thymidine uptake rates and activation of the Ras/Raf-1 mitogenic cascade. Such cells showed, however, a flat morphology and contained intact actin cables and fibronectin network. Our studies indicate that the v-Fms molecule controls cell morphology by a cascade that involves a direct interaction with p120RasGAP and p190RhoGAP: (i) in contrast to wt v-Fms molecules, the Y807F v-Fms protein failed to associate with and phosphorylate p120RasGAP; (ii) tight complexes between p120RasGAP and p190RhoGAP as well as detectable RhoGAP activity were present exclusively in wt-v-Fms cells; and (iii) p190RhoGAP was dispersed throughout the cytoplasm of wt-v-Fms cells, whereas its distribution was restricted to perinuclear regions of cells expressing the mutant v-Fms gene