fig2

Figure 2. Cubilin protein structure. Cubilin (CUBN) is a 460 kDa glycoprotein with no transmembrane domain. It acts as a receptor for intrinsic factor-vitamin B12 complexes. There are 27 CUB domains. The intrinsic factor and the vitamin B12 binding region are located in domains 5 to 8. The precise location of the binding sites for albumin remains unclear, but it is supposed to be in the CUB domains near the C-terminal area. IGS: Imerslund-Grasbëck syndrome; IF: intrinsic factor.