scholarly journals Ligand-binding characteristics of recombinant amino- and carboxyl-terminal fragments of human insulin-like growth factor-binding protein-3

2001 ◽  
Vol 169 (1) ◽  
pp. 123-133 ◽  
Author(s):  
M Galanis ◽  
SM Firth ◽  
J Bond ◽  
A Nathanielsz ◽  
AA Kortt ◽  
...  
Keyword(s):  
Growth Factor ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Factor Binding ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Igf I ◽  
Igf Binding ◽  
Carboxyl Terminal ◽  
Igfbp 3

Insulin-like growth factor-binding protein-3 (IGFBP-3) is a member of a family of structurally conserved proteins (IGFBP-1 to -6) which act as carriers and regulators of the mitogenic peptide hormones IGF-I and IGF-II. Members of the IGFBP family share conserved cysteine-rich amino- and carboxyl-terminal regions. The amino-terminal domain of these proteins is recognised to contain an IGF-binding determinant, but evidence to support a binding site in the carboxyl-terminal region of the protein is less rigorous. To further investigate this, we have synthesised both the amino-terminal (residues 1-88; N-88) and carboxyl-terminal (residues 165-264; C-165) domains of human IGFBP-3 in bacteria, as fusion proteins with a carboxyl-terminal FLAG peptide. Although only C-165 showed binding to IGF-I and -II by solution-binding assays, both N-88 and C-165 demonstrated binding to IGF-I and -II by biosensor analysis albeit with reduced affinities compared with full-length IGFBP-3. Only the carboxyl-terminal fragment (C-165) was able to form hetero-trimeric complexes with IGF-I and the acid-labile subunit (ALS). We conclude that the carboxyl-terminal domain of IGFBP-3 contains an IGF-binding determinant and can form ternary complexes with ALS.

The ovine pancreatic protein which binds insulin-like growth factor binding protein-3 is procarboxypeptidase A

1996 ◽  
Vol 150 (1) ◽  
pp. 51-56 ◽  
Author(s):  
P J Fowke ◽  
S C Hodgkinson
Keyword(s):  
Growth Factor ◽  
Cell Surface ◽  
Binding Protein ◽  
Binding Activity ◽  
Insulin Like Growth Factor ◽  
Surface Binding ◽  
Factor Binding ◽  
Amino Terminal ◽  
Igf I ◽  
Igfbp 3

Abstract Insulin-like growth factor binding protein-3 (IGFBP-3) is known to modulate the actions of insulin-like growth factors (IGF)-I and -II at the level of the cell. Proposed mechanisms include association of IGFBP-3 with cell surface proteoglycan, with cell surface binding proteins, proteolysis and/or internalization of IGFBP-3. In previous studies we have characterized a protein of 40 kDa in extracts of ovine pancreas and muscle which binds IGFBP-3 on ligand blot analyses. This paper reports the identity of the pancreatic species as procarboxypeptidase A (peptidyl-l-amino acid hydrolase, E.C. 3.4.17.1; proCPA). Identity was established by amino terminal sequence analysis, binding studies with pure bovine carboxypeptidase A (CPA) and observations that the binding activity was present in pancreatic secretions consistent with the role of proCPA as a secretory zymogen. The binding activity was inhibited by unlabelled IGFBP-3 at high doses (10 μg/ml) and reduced but not abolished by preincubation of 125I-IGFBP-3 with excess IGF-I. Digestion of 125I-IGFBP-3 with mature CPA produced a 26 kDa product. Modification of IGFBP-3 by CPA or binding to proCPA may provide a mechanism for modulation of IGFBP activity and hence IGF action. Journal of Endocrinology (1996) 150, 51–56

Specimen processing time and measurement of total insulin-like growth factor-I (IGF-I), free IGF-I, and IGF binding protein-3 (IGFBP-3)

2006 ◽  
Vol 16 (2) ◽  
pp. 86-92 ◽  
Author(s):  
Tiffany G. Harris ◽  
Howard D. Strickler ◽  
Herbert Yu ◽  
Michael N. Pollak ◽  
E. Scott Monrad ◽  
...  
Keyword(s):  
Growth Factor ◽  
Processing Time ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Specimen Processing ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

scholarly journals Genetic Determinants of Circulating Insulin-Like Growth Factor (IGF)-I, IGF Binding Protein (BP)-1, and IGFBP-3 Levels in a Multiethnic Population

2007 ◽  
Vol 92 (9) ◽  
pp. 3660-3666 ◽  
Author(s):  
Iona Cheng ◽  
Katherine DeLellis Henderson ◽  
Christopher A. Haiman ◽  
Laurence N. Kolonel ◽  
Brian E. Henderson ◽  
...  
Keyword(s):  
Growth Factor ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Genetic Determinants ◽  
Igf I ◽  
Igf Binding ◽  
Multiethnic Population ◽  
Igf Binding Protein ◽  
Igfbp 3

scholarly journals Influence of Polymorphisms in Genes Encoding for Insulin-Like Growth Factor (IGF)-I, Insulin, and IGF-Binding Protein (IGFBP)-3 on IGF-I, IGF-II, and IGFBP-3 Levels in Umbilical Cord Plasma

2012 ◽  
Vol 77 (6) ◽  
pp. 341-350 ◽  
Author(s):  
Eva Landmann ◽  
Barbara Kollerits ◽  
Joachim Gerhard Kreuder ◽  
Werner Friedrich Blum ◽  
Florian Kronenberg ◽  
...  
Keyword(s):  
Growth Factor ◽  
Umbilical Cord ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Cord Plasma ◽  
Igf I ◽  
Genes Encoding ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

scholarly journals Insulin-Like Growth Factor (IGF)-Binding Protein-3 (IGFBP-3) Binds to Fibronectin (FN): Demonstration of IGF-I/IGFBP-3/FN Ternary Complexes in Human Plasma1

2001 ◽  
Vol 86 (5) ◽  
pp. 2104-2110 ◽  
Author(s):  
Yaoting Gui ◽  
Liam J. Murphy
Keyword(s):  
Growth Factor ◽  
Ternary Complexes ◽  
Insulin Like Growth Factor ◽  
Heparin Binding ◽  
Complementary Dna ◽  
Igf I ◽  
Igf Binding ◽  
Carboxyl Terminal ◽  
Igf Binding Protein ◽  
Igfbp 3

We used a yeast two-hybrid system to identify binding partners for insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3). A partial complementary DNA encoding the carboxyl-terminal of fibronectin (FN), including the cell binding site, the heparin-binding domain, and the fibrin-binding domain, was identified in a screen of a human placental complementary DNA library. The interaction of IGFBP-3 with FN and the 40-kDa heparin-binding carboxyl-terminal fragment of FN was confirmed using Western ligand blotting. Both glycosylated and nonglycosylated IGFBP-3 bound to FN with a Kd of approximately 0.3 nmol/L. IGF-I and IGFBP-1 had no effect on IGFBP-3 binding to FN. Competitive inhibition of IGFBP-3 binding to FN was observed in the presence of IGFBP-5 and heparin. The binding affinity of the immobilized IGFBP-3/FN complex for [125I]IGF-I (Kd = 0.8 nmol/L) was similar to that of IGFBP-3 alone. The presence of IGF-I/IGFBP-3/FN ternary complexes in human plasma was demonstrated by coimmunoprecipitation of IGFBP-3 and [125I]IGF-I with anti-FN monoclonal antibody. These data indicate that FN may have a role in the transportation of IGFBP-3 and IGF-I in the circulation and the sequestration of these proteins in tissues.

Radioimmunoassay of insulin-like growth factor-binding protein-6 in human serum and other body fluids

1992 ◽  
Vol 134 (1) ◽  
pp. 133-139 ◽  
Author(s):  
R. C. Baxter ◽  
H. Saunders
Keyword(s):  
Cerebrospinal Fluid ◽  
Growth Factor ◽  
Human Serum ◽  
Follicular Fluid ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Factor Binding ◽  
Igf I ◽  
The Mean ◽  
Igfbp 3

ABSTRACT A radioimmunoassay has been established for the insulin-like growth factor-binding protein, IGFBP-6, isolated from a human transformed fibroblast cell-line. The binding proteins IGFBP-I and IGFBP-3 did not cross-react, but both IGF-I and IGF-II markedly inhibited IGFBP-6 tracer binding to antiserum. This inhibition, greater for IGF-II than for IGF-I, was fully reversed by the addition of IGFBP-3 to sequester the IGFs. After fractionation of human serum and follicular fluid samples by gel chromatography, interference in the radioimmunoassay by fractions corresponding to the 150 kDa IGF-IGFBP complex could be eliminated by IGFBP-3. The equivalent fractions from cerebrospinal fluid and amniotic fluid fractionation did not interfere in the assay. The mean IGFBP-6 level in adult human serum was 0·221 ±0·110 mg/l, with values significantly higher in men than women, and slightly decreased in pregnancy. Similar values were seen in umbilical cord serum and in amniotic and follicular fluid samples, while the mean level in cerebrospinal fluid was slightly lower, 0·152±0·049 mg/l. This assay will facilitate studies on the regulation of IGFBP-6 production, and its role as an IGF carrier. Journal of Endocrinology (1992) 134, 133–139

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