IGFBP3

IGFBP3 or Insulin-like Growth Factor Binding Protein 3 is a protein that in humans is encoded by the IGFBP3 gene. It is one of the six high-affinity IGF binding proteins (IGFBP) and plays a key role in cell growth, apoptosis and cancer.

Function

IGFBP3 binds both IGF-I and IGF-II with high affinity. It is the most abundant IGF binding protein in most bodily fluids and acts as a transporter of IGFs in blood circulation. In tissues, it prolongs the half-life of IGFs and alters their interaction with cell surface receptors.

Clinical Significance

Alterations in the serum concentration of IGFBP3 are often associated with growth hormone deficiency, acromegaly, malnutrition, and prolonged fasting. IGFBP3 is also implicated in breast cancer, prostate cancer, lung cancer, and colorectal cancer, with both promotional and inhibitory effects reported.

Genetics

The IGFBP3 gene is located on the long (q) arm of chromosome 7 at position 12.3. The gene spans 5.1 kb and contains 4 exons. Several polymorphisms in this gene are known to affect IGFBP3 levels and have been associated with the risk of various diseases, including cancer.

See Also

• Insulin-like Growth Factor
• Insulin-like Growth Factor 1
• Insulin-like Growth Factor 2
• Insulin-like Growth Factor Binding Protein