Unligated epidermal growth factor receptor forms higher order oligomers within microclusters on A431 cells that are sensitive to tyrosine kinase inhibitor binding

Andrew H A Clayton, Maria L Tavarnesi, Terrance Grant Johns

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Abstract

Characterization of the association states of the unligated epidermal growth factor receptor (EGFR) is important in understanding the mechanism of EGFR tyrosine kinase activation in a tumor cell environment. We analyzed, in detail, the association states of unligated, immunotagged EGFR on the surface of intact epidermoid carcinoma A431 cells, using AlexaFluor488 and AlexaFluor546 anti-EGFR antibody, mAb528, as probes. Image correlation microscopy revealed the presence of unligated EGFR in submicron scale clusters containing an average of 10-30 receptors (mean cluster density = 32 +/- 9 clusters per square micron). Lifetime-based Forster resonance energy transfer (FRET) techniques as a function of acceptor:donor labeling ratio disclosed a clustering of the unligated EGFR in clusters containing an average of four receptors on the nanometer (
Original languageEnglish
Pages (from-to)4589 - 4597
Number of pages9
JournalBiochemistry
Volume46
Issue number15
Publication statusPublished - 2007
Externally publishedYes

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