The bovine mannose 6-phosphate/insulin-like growth factor II receptor. Localization of the insulin-like growth factor II binding site to domains 5-11.
The mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF-II receptor) binds two distinct ligands, mannose 6-phosphate (Man-6-P) and insulin-like growth factor II (IGF-II). The extracytoplasmic region of the receptor is composed of 15 homologous repeating domains and domains 1-3 and 7-9 have been shown to contain the two Man-6-P binding sites. To determine the location of the single IGF-II binding site, truncated forms of the M6P/IGF-II receptor were expressed transiently in COS-1 cells and assayed for their ability to bind iodinated human recombinant IGF-II. The binding of [125I]IGF-II to the receptors in the presence or absence of excess unlabeled IGF-II, IGF-I, or insulin was determined by incubation with homobifunctional cross-linking agents followed by SDS-polyacrylamide gel electrophoresis. These binding studies demonstrated that a construct encoding domains 5-11 bound 0.9 mol of IGF-II/mol of receptor, whereas a construct encoding domains 5-10 exhibited no detectable binding to IGF-II. These results indicate that the IGF-II binding site of the M6P/IGF-II receptor is contained within domains 5-11 and that residues in domain 11 play an important role in IGF-II binding.
Dahms
N M
NM
Department of Biochemistry, Medical College of Wisconsin, Milwaukee 53226.
Wick
D A
DA
Brzycki-Wessell
M A
MA
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002417:Cattle; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D008360:Mannosephosphates / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D017527:Receptor, IGF Type 2 / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D015183:Restriction Mapping; D017384:Sequence Deletion
D007328:Insulin; D008360:Mannosephosphates; D009838:Oligodeoxyribonucleotides; D017527:Receptor, IGF Type 2; D011994:Recombinant Proteins; C027693:mannose-6-phosphate; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II