Biomaterial Database

Rat PC12 pheochromocytoma cells synthesize insulin-like growth factor-binding protein-6. 1993

L A Bach, and L Y Tseng, and J E Swartz, and M M Rechler

Molecular and Cellular Endocrinology Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892.

The PC12 cell line established from a rat pheochromocytoma has been extensively studied as a model of neuronal differentiation. Insulin-like growth factor-I (IGF-I) and IGF-II are mitogenic for PC12 cells under serum-starved conditions. IGF activity is modulated by a family of six IGF-binding proteins (IGFBPs). It recently was reported that PC12 cells produced an IGFBP that had a marked preferential binding affinity for IGF-II over IGF-I. We now show that the main IGFBP produced by PC12 cells is rat IGFBP-6 and compare its properties with those of human IGFBP-6. The predominant IGFBP in medium conditioned by undifferentiated and differentiated PC12 cells migrated on sodium dodecyl sulfate-12% polyacrylamide gel electrophoresis with an apparent molecular mass of 22.5-25 kilodaltons and was recognized by polyclonal antiserum to rat IGFBP-6 by immunoblotting. Rat IGFBP-6 mRNA (1.4 kilobases) was detected by Northern hybridization of total RNA extracted from PC12 cells using a rat IGFBP-6 cDNA probe. Rat IGFBP-6, like human IGFBP-6, is O-glycosylated; incubation with neuraminidase, fucosidase, and O-glycanase reduced its apparent molecular mass to 21 kilodaltons. Competitive binding studies of rat and human IGFBP-6 with [125I]IGF-II and unlabeled IGF-II or IGF-I demonstrated that both IGFBPs bound IGF-II with similar affinities (Ka, 1.5-1.8 x 10(11) M-1) and bound IGF-I with approximately 25- to 35-fold lower affinity than IGF-II. Thus, differences in amino acid sequence, such as deletion of nine amino-terminal residues (including two conserved cysteine residues) in rat IGFBP-6 compared with human IGFBP-6, do not alter its binding characteristics. PC12 cells should provide a useful system to define the regulation of IGFBP-6 expression and the role of IGFBP-6 in modulating IGF action.

UI	MeSH Term	Description	Entries
D007335	Insulin-Like Growth Factor II	A well-characterized neutral peptide believed to be secreted by the LIVER and to circulate in the BLOOD. It has growth-regulating, insulin-like and mitogenic activities. The growth factor has a major, but not absolute, dependence on SOMATOTROPIN. It is believed to be a major fetal growth factor in contrast to INSULIN-LIKE GROWTH FACTOR I, which is a major growth factor in adults.	IGF-II,Multiplication-Stimulating Activity,Somatomedin MSA,IGF-2,Insulin Like Growth Factor II,Insulin-Like Somatomedin Peptide II,Multiplication-Stimulating Factor,Somatomedin A,Factor, Multiplication-Stimulating,Insulin Like Somatomedin Peptide II,Multiplication Stimulating Activity,Multiplication Stimulating Factor
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D011994	Recombinant Proteins	Proteins prepared by recombinant DNA technology.	Biosynthetic Protein,Biosynthetic Proteins,DNA Recombinant Proteins,Recombinant Protein,Proteins, Biosynthetic,Proteins, Recombinant DNA,DNA Proteins, Recombinant,Protein, Biosynthetic,Protein, Recombinant,Proteins, DNA Recombinant,Proteins, Recombinant,Recombinant DNA Proteins,Recombinant Proteins, DNA
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D002454	Cell Differentiation	Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.	Differentiation, Cell,Cell Differentiations,Differentiations, Cell
D002850	Chromatography, Gel	Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.	Chromatography, Exclusion,Chromatography, Gel Permeation,Chromatography, Molecular Sieve,Gel Filtration,Gel Filtration Chromatography,Chromatography, Size Exclusion,Exclusion Chromatography,Gel Chromatography,Gel Permeation Chromatography,Molecular Sieve Chromatography,Chromatography, Gel Filtration,Exclusion Chromatography, Size,Filtration Chromatography, Gel,Filtration, Gel,Sieve Chromatography, Molecular,Size Exclusion Chromatography
D006031	Glycosylation	The synthetic chemistry reaction or enzymatic reaction of adding carbohydrate or glycosyl groups. GLYCOSYLTRANSFERASES carry out the enzymatic glycosylation reactions. The spontaneous, non-enzymatic attachment of reducing sugars to free amino groups in proteins, lipids, or nucleic acids is called GLYCATION (see MAILLARD REACTION).	Protein Glycosylation,Glycosylation, Protein
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001667	Binding, Competitive	The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.	Competitive Binding