Figure 1.

Mitophagy receptors. (A) SPATA33 functions as a mitophagy receptor. The C terminus of SPATA33 can interact with the mitochondrial outer membrane protein VDAC2. The N terminus of SPATA33 can bind to the WD40 region of ATG16L1. Upon starvation stress, damaged mitochondria are engulfed by autophagic membranes through SPATA33 linking VDAC2 and ATG16L1 to initiate mitophagy. (B) Ubiquitin-independent mitophagy. The autophagy receptors are outer mitochondrial membrane proteins, which have a common LIR/AIM motif that can bind to LC3B/Atg8 on the phagophore. (C) PINK-PRKN- or ubiquitin-dependent mitophagy. Mitophagy receptors are cytosolic proteins (CALCOCO2/NDP52 and OPTN), which bind ubiquitin. Accordingly, cytosolic receptors CALCOCO2/NDP52 and OPTN have both an AIM/LIR motif and a ubiquitin-binding domain. (D) The receptor SPATA33 mediates mitophagy via bridging between ATG16L1 and VDAC2, which is ATG16L1 dependent