The protein encoded by NBR1 ?NBR1, autophagy cargo receptor)was originally identified as an ovarian tumor antigen monitored in ovarian cancer. The encoded protein contains a B-box/coiled-coil motif, which is present in many genes with transformation potential. It functions as a specific autophagy receptor for the selective autophagic degradation of peroxisomes by forming intracellular inclusions with ubiquitylated autophagic substrates. NBR1 is located on a region of chromosome 17q21.1 that is in close proximity to the BRCA1 tumor suppressor gene. Alternative splicing of NBR1 results in multiple transcript variants.