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Kinetics of EGF receptor dimer formation
Author(s) -
Yang Katherine S,
Pike Linda J
Publication year - 2008
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/fasebj.22.1_supplement.646.6
Subject(s) - receptor , luciferase , dimer , chemistry , ligand (biochemistry) , biophysics , transfection , kinetics , complementation , ligand binding assay , microbiology and biotechnology , biochemistry , biology , mutant , gene , physics , organic chemistry , quantum mechanics
The EGF receptor is thought to exist in the membrane as a monomer that dimerizes in response to ligand binding. Studies on the relationship between ligand binding and dimer formation have been hampered by the lack of an assay that can follow receptor dimerization in living cells in real time. Here we report the use of a split‐luciferase enzyme complementation assay to study the kinetics of EGF receptor dimerization in intact cells. For the assay, the EGF receptor was C‐terminally fused to the N‐terminal or C‐terminal half of firefly luciferase and both constructs transfected into CHO cells. In the absence of ligand, significant basal light production was observed. Addition of EGF led to a rapid decrease in light production during the first two minutes, followed by a rebound in light production over the ensuing 3 to 5 min. The data suggest that under resting conditions, the C‐terminal tails of the EGF receptor are in proximity to each other, possibly in pre‐formed dimers, and that ligand binding induces a conformational change that disrupts these interactions but ultimately allows the formation of an alternative oligomeric state of the receptor. This work is supported by NIH grant GM64491to LJP.