Activation of the epidermal growth factor receptor tyrosine protein kinase in the absence of receptor oligomerization
Graduate School of Biomedical Sciences; Department of Biochemistry; Program in Molecular Medicine
Medical Subject Headings
Cell Line; Centrifugation, Density Gradient; Enzyme Activation; Humans; Molecular Weight; Polymers; Protein-Tyrosine Kinases; Receptor, Epidermal Growth Factor; Sphingosine
Life Sciences | Medicine and Health Sciences
The epidermal growth factor (EGF) receptor exists in a monomeric (170 kDa) form and in several aggregated states (360 kDa, greater than 500 kDa). The hypothesis that the oligomerization of the receptor is required for the stimulation of the kinase was tested by correlating the oligomeric state of the receptor with the protein kinase activity. EGF and sphingosine stimulate the phosphorylation of an exogenous peptide substrate by the receptor to an equal extent. Chemical cross-linking using disuccinimidyl suberate and the analysis of EGF receptor complexes by Western blotting demonstrated that EGF caused the aggregation of receptors. Similar results were obtained when [32P]phosphate-labeled receptors were cross-linked using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. These results were confirmed by sucrose density gradient sedimentation analysis. In contrast to the effects of EGF, incubation of EGF receptors with sphingosine did not cause the oligomerization of the receptors. These data demonstrate that the EGF receptor kinase can be stimulated independently of the aggregation of the receptors.
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Citation: J Biol Chem. 1988 Jun 5;263(16):7450-3.
The Journal of biological chemistry
Northwood, Ingrid C. and Davis, Roger J., "Activation of the epidermal growth factor receptor tyrosine protein kinase in the absence of receptor oligomerization" (1988). GSBS Student Publications. 904.