Muc4–ErbB2 Complex Formation and Signaling in Polarized CACO-2 Epithelial Cells Indicate That Muc4 Acts as an Unorthodox Ligand for ErbB2

Abstract
Muc4 serves as an intramembrane ligand for the receptor tyrosine kinase ErbB2. The time to complex formation and the stoichiometry of the complex were determined to be