Insulin-like growth factor I receptor primary structure: comparison with insulin receptor suggests structural determinants that define functional specificity.
To identify structural characteristics of the closely related cell surface receptors for insulin and IGF-I that define their distinct physiological roles, we determined the complete primary structure of the human IGF-I receptor from cloned cDNA. The deduced sequence predicts a 1367 amino acid receptor precursor, including a 30-residue signal peptide, which is removed during translocation of the nascent polypeptide chain. The 1337 residue, unmodified proreceptor polypeptide has a predicted Mr of 151,869, which compares with the 180,000 Mr IGF-I receptor precursor. In analogy with the 152,784 Mr insulin receptor precursor, cleavage of the Arg-Lys-Arg-Arg sequence at position 707 of the IGF-I receptor precursor will generate alpha (80,423 Mr) and beta (70,866 Mr) subunits, which compare with approximately 135,000 Mr (alpha) and 90,000 Mr (beta) fully glycosylated subunits.
D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004247:DNA / Q000032:analysis; D005260:Female; D006801:Humans; D010920:Placenta / Q000378:metabolism; D011061:Poly A / Q000235:genetics; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics; D011972:Receptor, Insulin / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D017451:Receptors, Somatomedin; D012689:Sequence Homology, Nucleic Acid
D012333:RNA, Messenger; D017451:Receptors, Somatomedin; D011061:Poly A; D004247:DNA; D011972:Receptor, Insulin