Function: Plays an essential role in autophagy (By similarity).
Subunit: Homooligomer. Interacts with ATG5. Part of either the minor and major complexes respectively composed of 4 sets of ATG12-ATG5 and ATG16L1 (400 kDa) or 8 sets of ATG12-ATG5 and ATG16L1 (800 kDa) (By similarity).