Acts as a receptor for reticulophagy. Directs autophagic sequestration of folded tubules/sheets derived from the cortical endoplasmic reticulum (cER) and the cytoplasmic endoplasmic reticulum (cytoER) into autophagosomes. Is not required for the cytoplasm-to-vacuole targeting pathway, mitophagy, pexophagy, and non-selective autophagy. Interacts with ATG8 and ATG11. Induced in absence of NAP1 (PubMed:12788058). Expression is increased by rapamycin, which mimics nitrogen starvation by inactivating the TORC1 complex (PubMed:26040717). Partially blocks reticulophagy, and the double ATG39/ATG40 knockout almost completely blocks this pathway. Leads to a more densely reticulated cytoplasmic endoplasmic reticulum (cER). Present with 1890 molecules/cell in log phase SD medium.