Download Insulin-like Growth Factor Binding Protein

Insulin-like Growth Factor Binding Protein-4
human, recombinant, expressed in mouse NSO cells
Product Number I4402
Product Description
Insulin-like Growth Factor Binding Protein-4
(IGFBP-4) is produced from a DNA sequence encoding
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the mature human IGFBP-4 protein (Asp 22-Glu 258)
and fused to the signal peptide of CD33. The chimera is
expressed in a mouse myeloma celll line, NSO. Met 17
from the CD33 signal peptide was retained in the
recombinant mature human IGFBP-4. Mature human
IGFBP-4 including an N-terminal methionine is a 238
amino acid residue protein, which has a calculated
molecular mass of ~26 kDa. Due to glycosylation, the
recombinant protein migrates as a 32 kDa and 25 kDa
protein under reducing and non-reducing conditions,
respectively. Human IGFBP-4 has a potential N-linked
glycosylation site and shares 90% amino acid
sequence identity with both mouse and rat IGFBP-4.
Insulin-like growth factor binding protein-4 (IGFBP-4) is
a member of the superfamily of insulin-like growth
factor (IGF) binding proteins which include six highaffinity IGF binding proteins (IGFBP) and at least four
low-affinity binding proteins referred to as IGFBP
related proteins (IGFBP-rP). The IGFBP members are
cysteine-rich proteins with conserved cysteine residues,
clustered in the amino-terminal and the carboxyterminal regions of the molecule. IGFBP-4 was isolated
from human plasma based on its ability to bind
immobilized IGF-1.
IGFBPs hold a central position in IGF ligand-receptor
interactions through influences on both the bioavailability and distribution of IGFs in the extracellular
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environment. IGFBPs will either inhibit or enhance the
biological activities of IGF or act in an IGF-independent
manner. Post-translational modification of IGFBPs,
including phosphorylation and proteolysis, will modify
the affinities of the binding proteins for IGF and may
indirectly regulate IGF actions. IGFBP-4 functions as an
inhibitor of IGF action and its main function may be to
protect cells from overstimulation by IGFs or to allow
activation of alternate transmembrane signaling
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pathways that are inhibited by IGF exposure.
Insulin-like growth factor binding protein-4 (IGFBP-4) is
expressed in multiple tissues including adrenal, testis,
spleen, heart, lung, kidney, liver, stomach, hypothalamus, and brain cortex. High expression levels are
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found in the non-paranchymal cells of the liver.
IGFBP-4 is the predominant IGFBP expressed by
human osteoblast-like cells and is also expressed in
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skin fibroblasts.
Reagent
The product is supplied as ~25 µg of protein lyophilized
from a 0.2 µm filtered solution in phosphate buffered
saline containing 50 µg of bovine serum albumin per 1
µg of cytokine.
Preparation Instructions
Reconstitute the contents of the vial using sterile
phosphate-buffered saline (PBS) containing at least
0.1% human serum albumin or bovine serum albumin.
Prepare a stock solution of no less than 25 µg/ml.
Storage/Stability
Store at −20 °C or −70 °C. Upon reconstitution, the
product may be stored at 2-8 °C for up to one month.
For extended storage, freeze in working aliquots.
Repeated freezing and thawing is not recommended.
Do not store in a frost-free freezer.
Product Profile
Insulin-like growth factor binding protein-4 (IGFBP-4) is
measured by its ability to inhibit the biological activity of
recombinant human IGF-I or recombinant human IGF-II
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on MCF-7 cells.
The ED50 is defined as the effective concentration of
growth factor that elicits a 50% increase in cell growth
in a cell based bioassay.
References
1. Keifer, M., et al., Identification and molecular
cloning of two new 30-kDa insulin-like growth factor
binding proteins isolated from adult human serum.
J. Biol. Chem., 266, 9043-9049 (1991).
2. Kelley, K.M., et al., Insulin-like growth factorbinding proteins (IGFBPs) and their regulatory
dynamics, Int. J. Biochem. Cell Biol., 28, 619-637
(1996).
3. Jones, J.I., and Clemmons, D.R., Insulin-like
growth factors and their binding proteins: biological
actions. Endocr. Rev., 16, 3-34 (1995).
4.
5.
6.
Shimasaki, S., et al., Molecular cloning of the
cDNAs encoding a novel insulin-like growth factorbinding protein from rat and human. Mol.
Endocrinol., 4, 1451-1458 (1990).
LaTour, D., et al., Inhibitory insulin-like growth
factor-binding protein: cloning, complete sequence,
and physiological regulation. Mol. Endocrinol., 4,
1806-1814 (1990).
Karey, K.P., and Sirbasku, D.A., Differential
responsiveness of human breast cancer cell lines
MCF-7 and T47D to growth factors and 17-β
estradiol. Cancer Research, 48, 4083-4092 (1988).
KAA 01/06
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