The primary structure of human cubilin as translated from cDNA clones. The predicted signal sequence is shown in italic type. The amino-terminal defined by protein sequencing is underlined. Potential N-glycosylation sites are shown in bold type. The figure on the right side represents the organization of extracellular modules. Their positions correspond to the sequence to the left. The mass of the peptide of the precursor is 396.280 kD and 395.041 kD after cleavage at the furin recognition site, thus suggesting that carbohydrate accounts for approximately 14% of the processed 460-kD glycoprotein.