Faculty Collaboration Database

Aggregation-induced activation of the epidermal growth factor receptor protein tyrosine kinase. Biochemistry 1993 Aug 31;32(34):8742-8

Date

08/31/1993

Pubmed ID

8395880

DOI

10.1021/bi00085a004

Scopus ID

2-s2.0-0027303959 (requires institutional sign-in at Scopus site)   55 Citations

Abstract

Various agents are able to stimulate the EGF receptor protein tyrosine kinase in the absence of ligand binding. To characterize their mechanism of action, we investigated their effects on the kinase activity of the intracellular domain of the EGF receptor (EGFR-IC). EGFR-IC (67 kDa) lacking the extracellular domain and transmembrane segment of the EGF receptor, but retaining kinase and autophosphorylation domains, was produced and purified as a soluble, cytoplasmic protein from Sf9 insect cells infected with a recombinant baculovirus. EGFR-IC was able to undergo autophosphorylation in a manner similar to full-length EGFR. Synthetic substrate peptides showed similar affinity to EGFR-IC as to the full-length receptor. The activity of the EGFR-IC was found to be dependent on divalent cations, Mn2+ being a more potent activator than Mg2+. Agents capable of aggregating the kinase by direct interaction (cross-linking antibodies, polycations) or through altering the surrounding solvent structure and thereby decreasing protein solubility [ammonium sulfate, poly(ethylene glycol), 2-methyl-2,4-pentanediol] activated the kinase in a manner which correlated with their ability to precipitate the EGFR intracellular domain. The widely different chemical nature of these agents suggests that they do not act by direct interaction with specific allosteric regulatory sites, but rather by facilitating the interactions between kinase molecules. These results support the hypothesis that full-length receptor aggregation itself, induced by ligand binding to the extracellular domain, results in intracellular domain interactions and the activation of kinase activity.

Author List

Mohammadi M, Honegger A, Sorokin A, Ullrich A, Schlessinger J, Hurwitz DR

Author

Andrey Sorokin PhD Professor in the Medicine department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Antibodies
Baculoviridae
Cations
Cells, Cultured
Enzyme Activation
ErbB Receptors
Humans
Manganese
Moths
Precipitin Tests
Protein-Tyrosine Kinases
Proteins