Preparation and characterization of Alexa Fluor 594-labeled epidermal growth factor for fluorescence resonance energy transfer studies: application to the epidermal growth factor receptor

2004 ◽  
Vol 324 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Kristin B Whitson ◽  
Joseph M Beechem ◽  
Albert H Beth ◽  
James V Staros
2015 ◽  
Vol 26 (22) ◽  
pp. 4087-4099 ◽  
Author(s):  
Christopher C. Valley ◽  
Donna J. Arndt-Jovin ◽  
Narain Karedla ◽  
Mara P. Steinkamp ◽  
Alexey I. Chizhik ◽  
...  

Mutations within the epidermal growth factor receptor (EGFR/erbB1/Her1) are often associated with tumorigenesis. In particular, a number of EGFR mutants that demonstrate ligand-independent signaling are common in non–small cell lung cancer (NSCLC), including kinase domain mutations L858R (also called L834R) and exon 19 deletions (e.g., ΔL747-P753insS), which collectively make up nearly 90% of mutations in NSCLC. The molecular mechanisms by which these mutations confer constitutive activity remain unresolved. Using multiple subdiffraction-limit imaging modalities, we reveal the altered receptor structure and interaction kinetics of NSCLC-associated EGFR mutants. We applied two-color single quantum dot tracking to quantify receptor dimerization kinetics on living cells and show that, in contrast to wild-type EGFR, mutants are capable of forming stable, ligand-independent dimers. Two-color superresolution localization microscopy confirmed ligand-independent aggregation of EGFR mutants. Live-cell Förster resonance energy transfer measurements revealed that the L858R kinase mutation alters ectodomain structure such that unliganded mutant EGFR adopts an extended, dimerization-competent conformation. Finally, mutation of the putative dimerization arm confirmed a critical role for ectodomain engagement in ligand-independent signaling. These data support a model in which dysregulated activity of NSCLC-associated kinase mutants is driven by coordinated interactions involving both the kinase and extracellular domains that lead to enhanced dimerization.


2015 ◽  
Vol 34 (6) ◽  
pp. 418-422 ◽  
Author(s):  
Tomohiro Osaki ◽  
Cai-Xia Wang ◽  
Taro Tachibana ◽  
Masayuki Azuma ◽  
Masaya Kitamura ◽  
...  

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