Amnionless Antibodies

AMN is type I transmembrane protein that is required for surface expression of the extracellular membrane-associated protein, cubilin. The two form a complex termed CUBAM in which AMN mediates endocytosis of compounds bound by cubulin. AMN is required for embryonic primitive streak formation in the mouse, and is highly expressed on adult polarized epithelia in the small intestine and kidney proximal convoluted tubules. Mutations of AMN or cubilin cause Imersund-Grasbeck syndrome, also called megaloblastic anemia-1, characterized by malabsorption of cobalamin (vitamin B12).