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insulin-like growth factor-binding protein 3; IBP-3; IGF-binding protein 3; IGFBP-3 (IGFBP3, IBP3)
Function:
- the major circulating IGF binding protein postnatally
- associates with an 85 kD glycoprotein component (ALS) as well as IGF-1 & IGF-2 to form a 140-150 kD complex
- binds IGF2 more than IGF1
- IGF-binding proteins prolong the half-life of the IGFs
- they either inhibit or stimulate the growth promoting effects of the IGFs on cell culture
- they alter the interaction of IGFs with their cell surface receptors
- phosphorylation sites are present in the extracellular medium
- interacts with XLKD1 (putative)
- interacts with HN
Structure:
- thyroglobulin type-1 domain mediates interaction with HN
- contains 1 IGFBP N-terminal domain
- contains 1 thyroglobulin type-1 domain
Compartment: secreted
Expression:
- expressed by most tissues. present in plasma
- IGFBP3 levels are higher during extrauterine life & peak during puberty
- induced by in the presence of IGF1, insulin & other growth-stimulating factors such as growth hormone, EGF & phorbol esters
Related
IGF-binding protein complex acid labile subunit; ALS (IGFALS, ALS)
General
glycoprotein
insulin-like growth factor [IGF]-binding protein
phosphoprotein
Properties
SIZE: entity length = 291 aa
MW = 32 kD
COMPARTMENT: extracellular compartment
MOTIF: signal sequence {1-27}
binding site
SITE: 28-134
FOR-BINDING-OF: insulin-like growth factor (IGF)
MOTIF: IGFBP N-terminal {36-117}
N-glycosylation site {N116}
N-glycosylation site {N136}
threonine-rich region {138-161}
MOTIF: threonine residue (SEVERAL)
threonine-rich region {192-208}
MOTIF: threonine residue (SEVERAL)
Thr phosphorylation site {T195}
N-glycosylation site {N199}
Ser phosphorylation site {S201}
Thyroglobulin type-1 {210-285}
MOTIF: cysteine residue {C213}
MODIFICATION: cysteine residue {C240}
cysteine residue {C240}
MODIFICATION: cysteine residue {C213}
cysteine residue {C251}
MODIFICATION: cysteine residue {C262}
cysteine residue {C262}
MODIFICATION: cysteine residue {C251}
cysteine residue {C264}
MODIFICATION: cysteine residue {C285}
cysteine residue {C285}
MODIFICATION: cysteine residue {C264}
SECRETED-BY: hepatocyte
smooth muscle
Database Correlations
OMIM 146732
UniProt P17936
PFAM correlations
Entrez Gene 3486
Kegg hsa:3486
References
- UniProt :accession P17936
- NIEHS-SNPs
http://egp.gs.washington.edu/data/igfbp3/
- SHMPD; Singapore human mutation and polymorphism database
http://shmpd.bii.a-star.edu.sg/gene.php?genestart=A&genename=IGFBP3
- LeRoith et al, in: Insulin-like growth factors in the
brain. Neurotrophic Factors, Academic Press 1993,
pg 391
- Entrez Gene :accession 3486
Component-of
IGF-1/IGF binding protein 3/acid-labile subunit glycoprotein