IGFBP6

IGFBP6 (Insulin-like Growth Factor Binding Protein 6) is a protein that in humans is encoded by the IGFBP6 gene. It is a member of the Insulin-like growth factor binding protein (IGFBP) family and encodes a protein with an IGFBP domain and a thyroglobulin type-I domain. The protein binds both insulin-like growth factor (IGF) I and II and circulates in the plasma. Binding of this protein prolongs the half-life of the IGFs and alters their interaction with cell surface receptors.

Function

IGFBP6 is one of six binding proteins (IGFBP1-6) that have high affinity for IGF-I and IGF-II. IGFBP6, however, has the highest affinity for IGF-II. This protein is secreted into the bloodstream, where it binds to the IGFs and prolongs their half-life, thereby altering their interaction with cell surface receptors. IGFBP6 has been shown to inhibit the growth promoting effects of IGF-II on cell culture. It has also been identified as a tumor suppressor gene in some types of cancer.

Clinical significance

Alterations in the IGFBP6 gene have been associated with a variety of cancers, including breast cancer, prostate cancer, and colorectal cancer. Overexpression of IGFBP6 can inhibit cancer cell growth, suggesting a potential role in cancer therapy. In addition, IGFBP6 may play a role in rheumatoid arthritis, as levels of this protein are elevated in the synovial fluid of affected individuals.

See also

• Insulin-like growth factor
• Insulin-like growth factor binding protein
• Breast cancer
• Prostate cancer
• Colorectal cancer
• Rheumatoid arthritis