A highly efficient peptide substrate for EGFR activates the kinase by inducing aggregation

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Signaling

Background:

• Epidermal growth factor receptor (EGFR) kinase domain forms an asymmetric dimer for allosteric activation.
• EGFR typically phosphorylates substrates with low catalytic efficiency due to limited dimer formation in solution.

Purpose of the Study:

• To elucidate the mechanism by which Peptide C, a synthetic EGFR substrate, achieves significantly higher phosphorylation efficiency.
• To understand how Peptide C enhances EGFR kinase activity and substrate phosphorylation.

Main Methods:

• Investigated the interaction between Peptide C and EGFR kinase domain.
• Analyzed the effect of Peptide C on EGFR kinase activity and dimer formation.
• Examined the self-assembly properties of Peptide C and its effect on protein aggregation.

Main Results:

• Peptide C promotes the formation of the asymmetric EGFR kinase domain dimer, increasing kinase activity.
• Activation by Peptide C enhances the phosphorylation of other substrates.
• Peptide C forms fibrils independently and likely facilitates EGFR aggregation and activation via an aggregation-mediated mechanism.

Conclusions:

• A peptide substrate can enhance EGFR catalytic activity by promoting kinase domain dimerization.
• Aggregation of the EGFR kinase domain, mediated by Peptide C fibrils, is a key mechanism for activation.
• This study reveals a novel aggregation-mediated pathway for peptide substrate-induced activation of receptor tyrosine kinases.