CIITA : class II major histocompatibility complex transactivator

Description

The CIITA (class II major histocompatibility complex transactivator) is a protein-coding gene located on chromosome 16.

The CIITA gene provides instructions for making a protein that primarily helps control the activity (transcription) of genes called major histocompatibility complex (MHC) class II genes. Transcription is the first step in the production of proteins, and CIITA is critical for the production of specialized immune proteins called MHC class II proteins from these genes. The CIITA protein coordinates various proteins to turn on MHC class II gene transcription and allow the production of MHC class II proteins.MHC class II proteins are found on the surface of several types of immune cells, including white blood cells (lymphocytes) that are involved in immune reactions. These proteins play an important role in the body's immune response to foreign invaders, such as bacteria, viruses, and fungi. To help the body recognize and fight infections, MHC class II proteins bind to fragments of proteins (peptides) from foreign invaders so that other specialized immune system cells can interact with them. When these immune system cells recognize the peptides as harmful, they trigger the lymphocytes and other immune cells to launch immune responses to get rid of the foreign invaders.The CIITA protein also appears to play a role in enhancing the transcription of MHC class I genes, which provide instructions for making immune system proteins called MHC class I proteins. Like MHC class II proteins, MHC class I proteins attach to peptides from foreign invaders and present them to specific immune system cells. These cells then attack the foreign invaders to rid them from the body. While the CIITA protein is able to help promote MHC class I gene activity, it is not the primary regulator of these genes. Other proteins play a more prominent role in their transcription.

Essential for transcriptional activity of the HLA class II promoter; activation is via the proximal promoter (PubMed:8402893, PubMed:7749984, PubMed:17493635, PubMed:16600381). Does not bind DNA (PubMed:8402893, PubMed:7749984, PubMed:17493635, PubMed:16600381). May act in a coactivator-like fashion through protein-protein interactions by contacting factors binding to the proximal MHC class II promoter, to elements of the transcription machinery, or both PubMed:8402893, PubMed:7749984, (PubMed:17493635, PubMed:16600381). Alternatively it may activate HLA class II transcription by modifying proteins that bind to the MHC class II promoter (PubMed:8402893, PubMed:7749984, PubMed:17493635, PubMed:16600381). Also mediates enhanced MHC class I transcription; the promoter element requirements for CIITA-mediated transcription are distinct from those of constitutive MHC class I transcription, and CIITA can functionally replace TAF1 at these genes. Activates CD74 transcription (PubMed:32855215). Exhibits intrinsic GTP- stimulated acetyltransferase activity (PubMed:11172716). Exhibits serine/threonine protein kinase activity: can phosphorylate the TFIID component TAF7, the RAP74 subunit of the general transcription factor TFIIF, histone H2B at 'Ser-37' and other histones (in vitro) (PubMed:24036077). Has antiviral activity against Ebola virus and coronaviruses, including SARS-CoV-2 (PubMed:32855215). Induces resistance by up-regulation of the p41 isoform of CD74, which blocks cathepsin-mediated cleavage of viral glycoproteins, thereby preventing viral fusion (PubMed:32855215). {ECO:0000269|PubMed:11172716, ECO:0000269|PubMed:16600381, ECO:0000269|PubMed:17493635, ECO:0000269|PubMed:24036077, ECO:0000269|PubMed:32855215, ECO:0000269|PubMed:7749984, ECO:0000269|PubMed:8402893}

CIITA is also known as C2TA, CIITAIV, MHC2D1, MHC2TA, NLRA.

Associated Diseases

Comprehensive carrier screening

WES Whole Exome Sequencing

Clinical Exome Sequencing