Plays a role in promoting axonal degeneration following neuronal injury by toxic insult or trauma. Interacts with MYO3A. Found in the cytoplasm in the absence of MYO3A and localizes at filopodial tips in the presence of MYO3A. Severed Morn4 null axons show significantly reduced and delayed axonal degeneration following axotomy and protection is evident for at least 72 hrs, whereas wild-type axons degenerate within the first 12 hrs.