Figure 1.

Schematic model of reticulophagy and nucleophagy. Atg39 and Atg40 localize to the perinuclear ER (pnER)/nuclear envelope (NE) and the cytoplasmic ER (cytoER)/cortical ER (cER), respectively. These proteins also reside on pnER/NE-derived double-membrane vesicles or fragments (tubules or sheets) of cytoER/cER. It is still unclear whether these vesicles and fragments are formed in a manner coupled with autophagosome formation. The predicted topologies of Atg39 and Atg40 are also shown, in which Atg8 family-interacting motifs (AIMs) are located in the cytoplasmic regions. Atg39 and Atg40 are likely to bind to Atg8 on forming autophagosomal membranes via these motifs, thereby pnER/NE-derived vesicles and cytoER/cER fragments are respectively sequestered within autophagosomes.