Immunogen sequence: VFARVDCDQH SDIAQRYRIS KYPTLKLFRN GMMMKREYRG QRSVKALADY IRQQKSDPIQ EIRDLAEITT LDRSKRNIIG YFEQKDSDNY RVFERVANIL HDDCAFLSAF GDVSKPERYS GDNIIYKPPG HSAPD. Mediates thiol-dependent retention in the early secretory pathway, forming mixed dis