Inhibits CBL-SH3KBP1 complex mediated down-regulation of EGFR signaling by sequestration of SH3KBP1. Binds to SH3KBP1 and prevents its interaction with CBL and inhibits translocation of SH3KBP1 to EGFR containing vesicles upon EGF stimulation (PubMed:21830225). Monomer (By similarity). Interacts with CUL3; interaction is direct and forms a 5:5 heterodecamer (By similarity). Interacts (via PXXXPR motifs) with SH3KBP1 (via SH3 domains) (PubMed:11152963, PubMed:21830225). Directly interacts with cathepsin B/CTSB (By similarity). Belongs to the KCTD3 family.