Membrane-bound component of the endocytic receptor formed by AMN and CUBN (PubMed:30523278). Required for normal CUBN glycosylation and trafficking to the cell surface. The complex formed by AMN and CUBN is required for efficient absorption of vitamin B12. Required for normal CUBN-mediated protein transport in the kidney (By similarity). Interacts (via extracellular region) with CUBN/cubilin, giving rise to a huge complex containing one AMN chain and three CUBN chains. Detected in kidney cortex (at protein level). The complex formed by AMN and CUBN is composed of a 400 Angstrom long stem and a globular crown region. The stem region is probably formed by AMN and the CUBN N-terminal region, including the EGF-like domains. The crown is probably formed by the CUBN CUB domains. N-glycosylated. A soluble form arises by proteolytic removal of the membrane anchor.