STAT4

STAT4, also known as Signal Transducer and Activator of Transcription 4, is a protein encoded by the STAT4 gene in humans. This gene is located on chromosome 2q32.2. STAT4 is a member of the Signal Transducer and Activator of Transcription (STAT) family, which plays a crucial role in mediating cellular responses to cytokines and growth factors.

Upon activation by Janus kinases (JAKs), STAT4 translocates to the nucleus where it binds to specific DNA sequences. This binding initiates the transcription of target genes involved in immune responses and cell differentiation. STAT4 is particularly important in the development and function of T helper cells, specifically promoting the differentiation of naive T cells into T helper 1 (Th1) cells. It also contributes to the development and activation of natural killer (NK) cells and B cells.

Dysregulation of STAT4 activity has been implicated in various autoimmune and inflammatory diseases. Polymorphisms in the STAT4 gene have been associated with an increased risk of conditions such as rheumatoid arthritis, systemic lupus erythematosus, and type 1 diabetes. Its role in immune cell differentiation and cytokine signaling makes it a significant factor in maintaining immune homeostasis and its disruption can lead to pathological immune responses.