Fig. 2: The ATG12 and ATG8 ubiquitin-like conjugation systems. | Cell Discovery

Fig. 2: The ATG12 and ATG8 ubiquitin-like conjugation systems.

From: Activation and targeting of ATG8 protein lipidation

Fig. 2

Similar to the classical ubiquitination cascades, the ubiquitin-like proteins ATG12 and ATG8 undergo a series of enzymatic reactions. ATG8 is first modified by the ATG4 protease and, likewise for ATG12, is activated by the E1-like enzyme ATG7 with consumption of ATP (ACTIVATION). ATG8 and ATG12 are then conjugated to the target protein (ATG5) or lipid (Phosphatidylethanolamine, PE) by the cognate E2-like enzymes (ATG10 and ATG3) (CONJUGATION). The last step of ATG8 lipidation is stimulated by the E3-like ligase ATG12–ATG5–ATG16 complex (LIGATION), while the ATG12 conjugation system lacks a known enzyme for the E3-like ligase activity. The ATG12–ATG5 conjugate interacts with the coiled-coil protein ATG16 via the ATG5 subunit, and further assembles into a hexamer. Legend: the ATG8 protein family members are indicated in green and the ATG12 proteins are indicated in magenta.

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