John Libbey Eurotext



The receptor for intrinsic factor-vitamin B12 complexes, cubilin, is a multiligand protein and its structural abnormalities account for the hereditary megaloblastic anemia of Imerslund-Gräsbeck syndrome Volume 5, issue 4, Juillet - Août 1999


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In this brief review we report the structure of the intestinal receptor for the intrinsic factor-vitamin B12 complex. This 460 kDa receptor, named cubilin because CUB domains account for 80 % of its sequence, is characterized by the lack of a transmembrane domain and the ability to bind multiple ligands. The chromosomal localization of cubilin, as well as the structural abnormalities observed in Imerslund-Gräsbeck patients which have hereditary malabsorption of vitamin B12, establishes its role in the physiological transport of vitamin B12. The expression of cubilin in sites other than the gut, particularly by the kidney and materno-foetal interface, and the identification of ligands independent of B12 metabolism, such as apolipoprotein A-I, suggests that cubilin has other functions.