Ubiquitin-binding protein that specifically recognizes and binds 'Lys-63'-linked ubiquitin. Does not bind 'Lys-48'-linked ubiquitin. Positively regulates the internalization of ligand-activated EGFR by binding to the Ub moiety of ubiquitinated EGFR at the cell membrane (By similarity). Interacts (via the UIM 3 and 4 repeats) with EGFR (ubiquitinated); the interaction is direct, inhibited by ANKRD13A monoubiquitination and may regulate EGFR internalization. Interaction with EGFR may enhance association with the cell membrane. The UIM repeats 3 and 4 are required for binding to ubiquitinated EGFR and 'Lys-63'-linked ubiquitin. Monoubiquitinated, inhibits interaction with ubiquitinated EGFR. Extended N-terminus.