May play a role in craniofacial and inner ear morphogenesis during embryonic development. May act within the otic vesicle epithelium to control formation of the lateral semicircular canal in the inner ear, possibly by restricting the expression of NTN1 (By similarity). Interacts with EGFR, ERBB2 and ERBB4 (in vitro). Detected in cytoplasmic vesicles when coexpressed with ERBB4. Widely expressed. Truncated N-terminus.