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Kinase‐mediated quasi‐dimers of EGFR
Author(s) -
Bublil Erez M.,
Pines Gur,
Patel Gargi,
Fruhwirth Gilbert,
Ng Tony,
Yarden Yosef
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.10.166199
Subject(s) - protein kinase domain , tyrosine kinase , kinase , chemistry , erbb , extracellular , phosphorylation , epidermal growth factor receptor , biophysics , cytoplasm , receptor tyrosine kinase , microbiology and biotechnology , biochemistry , receptor , biology , mutant , gene
Ligand‐induced dimerization of the epidermal growth factor receptor (ErbB‐1/EGFR) involves conformational changes that expose an extracellular dimerization interface. Subsequent alterations within the cytoplasmic kinase domain, which culminate in tyrosine phosphorylation, are less understood. Our study addressed this question by using two strategies: a chimeric receptor approach employed ErbB‐3, whose defective kinase domain was replaced by the respective part of EGFR. The implanted full‐length kinase, unlike its subdomains, conferred dimerization and catalysis. The data infer that the kinase function of EGFR is restrained by the carboxyl tail; once grafted distally to the ectopic tail of ErbB‐3, the kinase domain acquires quasi‐dimerization and activation. In an attempt to alternatively refold the cytoplasmic tail, our other approach employed kinase inhibitors. Biophysical measurements and covalent cross‐linking analyses showed that inhibitors targeting the active conformation of EGFR, in contrast to a compound recognizing the inactive conformation, induce quasi‐dimers in a manner similar to the chimeric ErbB‐3 molecule. Collectively, these observations unveil ki‐nase domain‐mediated quasi‐dimers, which are regulated by an autoinhibitory carboxyl tail. On the basis of these observations, we propose that quasi‐dimers precede formation of ligand‐induced, fully active dimers, which are stabilized by both extracellular and intracellular receptor‐receptor interactions.—Bublil, E. M., Pines, G., Patel, G., Fruhwirth, G., Ng, T., Yosef Yarden. Kinase‐mediated quasi‐dimers of EGFR. FASEB J. 24, 4744–4755 (2010). www.fasebj.org