title: Influence of placental mannose/n-acetyl glucosamine-binding proteins on the interaction of insulin and insulin-like growth factors with their receptors.
abstract: Placenta is a source of carbohydrate-binding proteins that function as molecular scavengers, but they could also be involved in interactions that assist in metabolic control. Mannose/N-acetyl-glucosamine (Man/GlcNAc)-binding proteins from placenta were isolated and their reactivity towards placental insulin and insulin-like growth factor receptors (IR and IGF-Rs) was analyzed. The lectins reduced the binding of insulin and IGF-I in a dose-dependent manner, while almost no effect was observed on the binding of IGF-II. The shape of the inhibition curves changed, suggesting altered binding specificity. The presence of sugar could not reverse completely the effect of the lectins, implicating both lectin-sugar and protein-protein conformational recognition. Since biological molecules in our experimental system were those that are in close relation in vivo, placental Man/GlcNAc-specific lectins may be regarded as potential allosteric modulators of ligand-receptor interactions in a system of homologous ligands, selectively affecting only binding to tyrosine kinase type receptors (IR and IGF-1R).
authors.affiliation: Institute for the Application of Nuclear Energy, University of Belgrade, Serbia. olgica@inep.co.rs
authors.forename: O
authors.initials: O
authors.lastname: Nedic
authors.forename: D
authors.initials: D
authors.lastname: Filimonovic
authors.forename: Z
authors.initials: Z
authors.lastname: Mikovic
authors.forename: R
authors.initials: R
authors.lastname: Masnikosa
mesh_terms: D005260:Female; D005978:Glutathione / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000737:chemistry / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000737:chemistry / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D037102:Lectins / Q000737:chemistry / Q000378:metabolism*; D037601:Mannose-Binding Lectin / Q000737:chemistry / Q000378:metabolism; D010920:Placenta / Q000737:chemistry / Q000378:metabolism*; D011247:Pregnancy; D011485:Protein Binding; D017526:Receptor, IGF Type 1 / Q000737:chemistry / Q000378:metabolism*; D017527:Receptor, IGF Type 2 / Q000737:chemistry / Q000378:metabolism*; D011972:Receptor, Insulin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D007328:Insulin; D037102:Lectins; D037601:Mannose-Binding Lectin; D017527:Receptor, IGF Type 2; C084569:N-acetylglutathione; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D017526:Receptor, IGF Type 1; D011972:Receptor, Insulin; D005978:Glutathione