Since the surface of the ARM domain can typically accommodate only one peptide motif at any given time, all these proteins compete for the same cellular pool of β-catenin molecules. This competition is the key to understand how the Wnt signaling pathway works.
The competition for control over the cellular pool of β-catenin molecules, which arises from the ARM domain's limited capacity to accommodate multiple peptide motifs, is key to comprehending how the Wnt signaling pathway functions.