Tyrosine kinase activity is essential for the association of phospholipase C-gamma with the epidermal growth factor receptor.
Epidermal growth factor (EGF) treatment of NIH 3T3 cells transfected with wild-type EGF receptor induced tyrosine phosphorylation of phospholipase C-gamma (PLC-gamma). The EGF receptor and PLC-gamma were found to be physically associated such that antibodies directed against PLC-gamma or the EGF receptor coimmunoprecipitated both proteins. The association between PLC-gamma and wild-type EGF receptor was dependent on the concentration of EGF, but EGF did not enhance the association between PLC-gamma and a kinase-negative mutant of the EGF receptor. Oligomerization of the EGF receptor was not sufficient to induce association of the EGF receptor with PLC-gamma, since the kinase-negative mutant receptor underwent normal dimerization in response to EGF yet did not associate with PLC-gamma. The form of PLC-gamma associated with the EGF receptor appeared to be primarily the non-tyrosine-phosphorylated form. It is concluded that the kinase activity of the EGF receptor is essential for association of PLC-gamma with the EGF receptor, possibly by stimulating receptor autophosphorylation.
Margolis
B
B
Rorer Biotechnology, Inc., King of Prussia, Pennsylvania 19406.
Bellot
F
F
Honegger
A M
AM
Ullrich
A
A
Schlessinger
J
J
Zilberstein
A
A
D000818:Animals; D002478:Cells, Cultured; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D005796:Genes; D006801:Humans; D007700:Kinetics; D051379:Mice; D008815:Mice, Inbred Strains; D009154:Mutation; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D010738:Type C Phospholipases / Q000378:metabolism*
D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D010738:Type C Phospholipases