Biomaterial Database

Demonstration of type I insulin-like growth factor receptors on human platelets. 1989

K Hartmann, and T G Baier, and R Loibl, and A Schmitt, and D Schönberg

Department of Pediatrics, University of Heidelberg, FRG.

Human platelets, freshly isolated from healthy human adults, express receptors for insulin-like growth factor I. The IC50 for displacement of 125I-IGF-I binding by unlabeled IGF-I was 0.2 nM, by IGF-II 32 nM by insulin 160 nM. Scatchard analysis of IGF-I binding demonstrates dissociation constants of 0.14 +/- 0.08 nM for high affinity binding site and 54 +/- 18 nM for low affinity binding site. The presence of the alpha-subunit of type I IGF receptor, as high affinity binding site, was verified by affinity crosslinking of 125I-IGF-I to platelet surface membranes. Under reducing con-conditions a Mr = 135,000 band was preferentially labeled. The complete type I IGF receptor complex, which revealed under nonreducing conditions, has an approximately molecular mass of Mr greater than 400,000. The immunoprecipitation of the 125I-IGF-I cross-linked type I receptor with alpha IR-3 confirmed the results achieved by affinity crosslinking.

UI	MeSH Term	Description	Entries
D007334	Insulin-Like Growth Factor I	A well-characterized basic peptide believed to be secreted by the liver and to circulate in the blood. It has growth-regulating, insulin-like, and mitogenic activities. This growth factor has a major, but not absolute, dependence on GROWTH HORMONE. It is believed to be mainly active in adults in contrast to INSULIN-LIKE GROWTH FACTOR II, which is a major fetal growth factor.	IGF-I,Somatomedin C,IGF-1,IGF-I-SmC,Insulin Like Growth Factor I,Insulin-Like Somatomedin Peptide I,Insulin Like Somatomedin Peptide I
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D011233	Precipitin Tests	Serologic tests in which a positive reaction manifested by visible CHEMICAL PRECIPITATION occurs when a soluble ANTIGEN reacts with its precipitins, i.e., ANTIBODIES that can form a precipitate.	Precipitin Test,Test, Precipitin,Tests, Precipitin
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D001792	Blood Platelets	Non-nucleated disk-shaped cells formed in the megakaryocyte and found in the blood of all mammals. They are mainly involved in blood coagulation.	Platelets,Thrombocytes,Blood Platelet,Platelet,Platelet, Blood,Platelets, Blood,Thrombocyte
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D017451	Receptors, Somatomedin	Cell surface receptors that bind somatomedins and trigger intracellular changes which influence the behavior of cells. Studies have disclosed two types of receptors for this family of peptide hormones. The type I receptor is homologous to the insulin receptor and has tyrosine kinase activity. The type II receptor is identical to the mannose-6-phosphate receptor which is important in trafficking of lysosomal enzymes.	Receptors, Insulin-Like Growth Factors,Somatomedin Receptors,Insulin-Like Growth Factor Receptor,Insulin-Like Growth Factor Receptors,Somatomedin Receptor,Insulin Like Growth Factor Receptor,Insulin Like Growth Factor Receptors,Receptor, Somatomedin,Receptors, Insulin Like Growth Factors