Common elements in growth factor stimulation and oncogenic transformation: 85 kd phosphoprotein and phosphatidylinositol kinase activity

Cell. 1987 Sep 25;50(7):1021-9. doi: 10.1016/0092-8674(87)90168-1.

Abstract

The phosphorylation of proteins on tyrosine in vivo and in vitro was examined in 3T3 cells stimulated by platelet-derived growth factor (PDGF) and transformed by polyoma middle T antigen (MTAg) by using an antibody directed against phosphotyrosine (P-tyr). Two common events were observed upon PDGF stimulation or MTAg transformation of cells: the appearance in the immunoprecipitates of an 85 kd phosphoprotein, and increased phosphatidylinositol (PI) kinase activity. In PDGF-stimulated cells, the 85 kd phosphoprotein and PI kinase activity appeared rapidly, within 1 min of growth factor addition. The PI kinase activity and 85 kd phosphorylation were also increased in anti-P-tyr immunoprecipitates from cells transformed by v-fms and v-sis, but not by SV40 T antigen. The presence of the tyrosine-phosphorylated 85 kd protein correlated with PI kinase activity during several purification steps. These results suggest that the 85 kd phosphoprotein, a putative PI kinase, is a substrate for both the PDGF receptor and MTAg/pp60c-src tyrosine kinase activities.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 1-Phosphatidylinositol 4-Kinase
  • Animals
  • Antigens, Polyomavirus Transforming
  • Antigens, Viral, Tumor / pharmacology*
  • Cell Line
  • Cell Transformation, Neoplastic / metabolism*
  • Cell Transformation, Viral
  • Gene Expression Regulation / drug effects
  • Mice
  • Mice, Inbred BALB C
  • Oncogene Protein gp140(v-fms)
  • Oncogene Proteins v-sis
  • Oncogene Proteins, Viral / pharmacology*
  • Oncogenes
  • Phosphatidylinositols / metabolism
  • Phosphoproteins / isolation & purification*
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Phosphotransferases / isolation & purification*
  • Phosphotransferases / metabolism
  • Phosphotyrosine
  • Platelet-Derived Growth Factor / pharmacology*
  • Polyomavirus / enzymology
  • Protein-Tyrosine Kinases / metabolism
  • Retroviridae Proteins / physiology
  • Simian virus 40 / physiology
  • Substrate Specificity
  • Tyrosine / analogs & derivatives
  • Tyrosine / analysis

Substances

  • Antigens, Polyomavirus Transforming
  • Antigens, Viral, Tumor
  • Oncogene Protein gp140(v-fms)
  • Oncogene Proteins v-sis
  • Oncogene Proteins, Viral
  • Phosphatidylinositols
  • Phosphoproteins
  • Platelet-Derived Growth Factor
  • Retroviridae Proteins
  • Phosphotyrosine
  • Tyrosine
  • Phosphotransferases
  • 1-Phosphatidylinositol 4-Kinase
  • Protein-Tyrosine Kinases