Endoplasmic reticulum (ER)-anchored autophagy regulator which mediates ER delivery into lysosomes through sequestration into autophagosomes (PubMed:26040720, PubMed:31930741, PubMed:34338405). Promotes membrane remodeling and ER scission via its membrane bending capacity and targets the fragments into autophagosomes via interaction with ATG8 family proteins (PubMed:26040720, PubMed:31930741, PubMed:34338405). Active under basal conditions (PubMed:34338405). Required for collagen quality control in a LIR motif-dependent manner (By similarity). Required for long-term survival of nociceptive and autonomic ganglion neurons (PubMed:19838196, PubMed:26040720). {ECO:0000250|UniProtKB:Q8VE91, ECO:0000269|PubMed:19838196, ECO:0000269|PubMed:26040720, ECO:0000269|PubMed:34338405}. (Microbial infection) During SARS-CoV-2 infection, RETREG1- mediated reticulophagy is promoted by SARS-CoV-2 ORF3A protein (PubMed:35239449). This induces endoplasmic reticulum stress and inflammatory responses and facilitates viral infection (PubMed:35239449). . This is the function of RETREG1 (reticulophagy regulator 1, Ensembl gene identifier ENSG00000154153).