CIITA

CIITA (Class II Major Histocompatibility Complex Transactivator) is a protein that in humans is encoded by the CIITA gene. CIITA is a key regulator in the immune system, specifically in the expression of the Class II Major Histocompatibility Complex (MHC).

Function

CIITA is a transcription factor that regulates the expression of Class II MHC genes. The Class II MHC proteins are essential for the immune system's ability to present antigens to the T cells, a process known as antigen presentation. Without CIITA, the Class II MHC genes are not expressed, which can lead to a weakened immune response.

Structure

The CIITA protein is composed of several domains, each with a specific function. The N-terminal domain is involved in transcriptional activation, while the C-terminal domain is responsible for the protein's nuclear localization. The central region of the protein contains a proline-rich domain and a leucine-rich repeat (LRR) domain, which are thought to be involved in protein-protein interactions.

Clinical significance

Mutations in the CIITA gene can lead to a rare immunodeficiency disorder known as Bare Lymphocyte Syndrome type II (BLS II). This condition is characterized by a lack of MHC Class II expression, leading to severe combined immunodeficiency.

See also

• Major Histocompatibility Complex
• Transcription factor
• Antigen presentation
• Bare Lymphocyte Syndrome