Quantitative measurement of epidermal growth factor receptor-mitogen-activated protein kinase signal transduction using a nine-plex, peptide-based immunoassay.

Aberrant epidermal growth factor receptor (EGFR, ErbB1) signaling is implicated in cell transformation, motility, and invasion in a variety of cell types, and EGFR is the target of several anticancer drugs. However, the kinetics of EGFR signaling and the individual contributions of site-specific phosphorylation events remain largely unknown. A peptide-based, multiplex immunoassay approach was developed to simultaneously measure both total and phosphorylated protein in a single sample.