Regulates the trafficking and gating properties of AMPA-selective glutamate receptors (AMPARs) (By similarity). Plays an important role in the proper development of cranial nerves by facilitating the secretion of HBEGF. Interacts with HBEGF. Expressed in the odd-numbered neuromeres (r3 and r5) of the developing hindbrain. Belongs to the cornichon family.