Figure 6.

Regulators of autophagy. Growth factors and nutrients through PI3K/AKT and mTORC1, respectively, negatively regulate autophagy. AMP-activated protein kinase (AMPK) positively regulates autophagy. Autophagy is also regulated by the Beclin 1 interacting complex. Autophagosomal elongation requires the ATG5-ATG12 and LC3-ATG8 ubiquitin-like conjugation systems. In mammals, the conversion of LC3-I (free-form) to LC3-II (phosphoethanolamine-conjugated form) is used as a marker of autophagy. (Adapted, with permission, from Choi et al. 2013, © Massachusetts Medical Society.)