Anti-KDELR1 antibodies are used in the immunodetection of the protein KDEL endoplasmic reticulum protein retention receptor 1. In humans, the canonical protein has a reported length of 212 amino acid residues and a mass of 24.5 kDa. Its subcellular localization is in the ER, Golgi, and cytoplasmic vesicles. Up to 2 different isoforms have been reported for this protein. It is notably widely expressed in many tissue types. A member of the ERD2 protein family, KDELR1 is a known receptor for the C-terminal sequence motif K-D-E-L that is present on endoplasmic reticulum resident proteins and that mediates their recycling from the Golgi back to the endoplasmic reticulum. Post-translational modifications have been described, including phosphorylation. Synonyms for this target antigen include ERD2.1, HDEL, PM23, ER lumen protein-retaining receptor 1, KDEL (Lys-Asp-Glu-Leu) endoplasmic reticulum protein retention receptor 1, and ERD2. KDELR1 gene orthologs have been reported in the mouse, rat, bovine, frog and chimpanzee species.