STAT3

The STAT3 gene is part of a family known as the STAT genes. These genes provide instructions for making proteins that are part of essential chemical signaling pathways within cells. When STAT proteins are activated by certain chemical signals, they move into the nucleus and attach (bind) to specific areas of DNA. By binding to regulatory regions near genes, STAT proteins can regulate whether these genes are turned on or off. STAT proteins are called transcription factors on the basis of this action.

The STAT3 protein is involved in many cellular functions. It regulates genes that are involved in cell growth and division, cell movement, and the self-destruction of cells (apoptosis). The STAT3 protein is active in tissues throughout the body. It plays an important role in the development and function of several body systems and is essential for life. In the immune system, the STAT3 protein transmits signals that help control the body's response to foreign invaders such as bacteria and fungi. In particular, the protein is involved in the regulation of inflammation, which is one way the immune system responds to infection or injury. In the skeletal system, the STAT3 protein is involved in the formation of specialized cells that build and break down bone tissue. These cells are necessary for the normal development and maintenance of bones.

Job syndrome - caused by mutations in the STAT3 gene

At least 16 mutations in the STAT3 gene have been identified in people with Job syndrome. Most of these mutations change a single protein building block (amino acid) in the STAT3 protein. These mutations occur in regions of the protein that are critical for its activation or its ability to bind to DNA.

Little is known about the effects of STAT3 mutations on the body's cells and tissues. Researchers suspect that changes in this gene alter the structure and function of the STAT3 protein, impairing its ability to control the activity of other genes. The defective protein disrupts cellular functions such as immune system regulation. The resulting immune system abnormalities make people with Job syndrome highly susceptible to infections, particularly bacterial and fungal infections affecting the lungs and skin. Additionally, the role of STAT3 protein in the formation and maintenance of bone tissue may help explain why STAT3 gene mutations lead to the skeletal and dental abnormalities characteristic of this condition.

cancers - associated with the STAT3 gene

The STAT3 protein has been found to be overactive in several common forms of cancer. For example, abnormal STAT3 protein activation has been identified in many cancers of the breast, prostate, and pancreas, as well as cancers of blood-forming cells (leukemia and lymphoma).

Normally, the STAT3 protein is switched on and off in response to signals that control cell growth and development. A continuously active version of this protein relays messages to the nucleus even in the absence of these chemical signals. Researchers believe that the overactive STAT3 protein instructs cells to continue growing and dividing, and prevents damaged cells from self-destructing (undergoing apoptosis). Excess STAT3 protein may contribute to the growth of cancers by allowing abnormal cells to grow and divide uncontrollably.