Title
Biophysical Evidence for Intrinsic Disorder in the C-terminal Tails of the EGFR and HER3 Receptor Tyrosine Kinases
Author
Theodore R. Keppel, Kwabena Sarpong, Elisa M. Murray, John Monsey, Jian Zhu, Ron Bose
Year
2016
Journal
The Journal of Biological Chemistry
Abstract
The EGFR/ErbB family of receptor tyrosine kinases includes oncogenes important in the progression of breast and other cancers and they are targets for many drug development strategies. Each member of the ErbB family possesses a unique, structurally uncharacterized C-terminal tail that plays an important role in autophosphorylation and signal propagation. To determine if these C-terminal tails are intrinsically disordered regions, we conducted a battery of biophysical experiments on the EGFR and HER3 tails. Using hydrogen/deuterium exchange mass spectrometry, we measured the conformational dynamics of intracellular half constructs and compared the tails to the ordered kinase domains. The C-terminal tails demonstrate more rapid deuterium exchange behavior when compared to the kinase domains. Next, we expressed and purified EGFR and HER3 tail-only constructs. Results from circular dichroism spectroscopy, size-exclusion chromatography with multi-angle light scattering, dynamic light scattering, analytical ultracentrifugation, and small angle X-ray scattering each provide evidence that the EGFR and HER3 C-terminal tails are intrinsically disordered with extended, non-globular structure in solution. The intrinsic disorder and extended conformation of these tails may be important for their function by increasing the capture radius and reducing the thermodynamic barriers for binding of downstream signaling proteins.
Instrument
J-???
Keywords
Circular dichroism, Secondary structure, Biochemistry