SMAD4 gene

SMAD family member 4

The SMAD4 gene provides instructions for making a protein involved in transmitting chemical signals from the cell surface to the nucleus. The SMAD4 protein is part of a signaling pathway, called the transforming growth factor beta (TGF-β) pathway, that allows the environment outside the cell to affect gene activity and protein production within the cell. The signaling process begins when a TGF-β protein attaches (binds) to a receptor protein on the cell surface, which turns on (activates) a group of related SMAD proteins. The SMAD proteins bind to the SMAD4 protein and form a protein complex, which then moves to the cell nucleus. In the nucleus, the SMAD protein complex binds to specific areas of DNA where it controls the activity of particular genes and regulates cell growth and division (proliferation). By controlling these cellular processes, the SMAD4 protein is involved in the development of many body systems.

The SMAD4 protein serves both as a transcription factor and as a tumor suppressor. Transcription factors help control the activity of particular genes, and tumor suppressors keep cells from growing and dividing too fast or in an uncontrolled way.