fig2

Figure 2. Cubilin protein structure. Cubilin (CUB) is a 460 kDa glycoprotein without transmembrane domain. It acts as a receptor for intrinsic factor-vitamin B12 complexes. There are 27 CUB domains. Intrinsic factor and vitamin B12 binding region is located in domains 5 to 8. The precise location of the binding sites for albumin remains unclear, but it is supposed to be located in the CUB domains near the C-terminal area. IGS : Imerslund-Grasbëck syndrome; IF : intrinsic factor.