Plays a role in the maintenance of lens transparency, and may also play a role in muscle cell strength (By similarity). Involved in hippocampal neurite branching and neuromuscular junction formation, as a result plays a role in spatial memory functioning (By similarity). Activates transcription of APP (PubMed:14527950). Interacts (via C-terminus) with APP (via C-terminus) (PubMed:8855266, PubMed:14527950). Interacts with APLP2 (via cytoplasmic domain) (PubMed:8855266). Widely expressed. Contaminating sequence. Sequence of unknown origin in the N-terminal part.