When cross-linked to form dimers and trimers, it has a regulatory effect on ERK signaling pathway activity in response to EGF stimulation. Colocalizes with the EGF receptor in WDR54-specific vesicle where it sustains the internalization and controls the degradation of the EGF receptor after EGF stimulation. Homodimer and homotrimer; forms tight forms of dimers and trimers. Aggregates in vesicles when cross-linked. Expressed in epithelial cells (at protein level) (PubMed:29987896). Isoform 3 expression is highly increased in colorectal cancer cells (PubMed:29987896). WD6 repeat is required for cross-linking by TGM2. Cross-linked to tightly form both dimers and trimers by TGM2. Cross-linking enhances the activation of EGF receptor-mediated signaling pathway (PubMed:30458214). Cross-linking is inhibited by EGF (PubMed:30458214). Ubiquitinated. EGF increases ubiquitination.