cellular response to type II interferon

Definition

Target type: biologicalprocess

Any process that results in a change in state or activity of a cell (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of an interferon-gamma stimulus. Interferon gamma is the only member of the type II interferon found so far. [GOC:mah]

Cellular response to type II interferon, also known as interferon-gamma (IFN-γ), is a complex process that involves a cascade of signaling events leading to the activation of various genes and proteins. It plays a crucial role in the immune system's response to intracellular pathogens, particularly viruses and bacteria.

**1. Binding and Signal Transduction:**
IFN-γ binds to its specific receptor, IFNGR, which is a heterodimer composed of IFNGR1 and IFNGR2 subunits. This binding triggers the activation of the Janus Kinase (JAK)-Signal Transducer and Activator of Transcription (STAT) pathway.

**2. JAK Activation and STAT Phosphorylation:**
The binding of IFN-γ to IFNGR leads to the phosphorylation of JAK1 and JAK2 kinases associated with the receptor. Activated JAKs phosphorylate STAT1 and STAT2 transcription factors.

**3. STAT Dimerization and Nuclear Translocation:**
Phosphorylated STAT1 and STAT2 dimerize and translocate to the nucleus.

**4. Transcriptional Activation:**
In the nucleus, the STAT1/STAT2 dimer associates with interferon regulatory factor 9 (IRF9), forming the ISGF3 complex. This complex binds to specific DNA sequences called interferon-stimulated response elements (ISREs) in the promoters of IFN-γ-responsive genes.

**5. Gene Expression and Biological Effects:**
The binding of ISGF3 to ISREs leads to the transcription of numerous genes involved in various aspects of the cellular response to IFN-γ. These genes include:
* **Antiviral proteins:** such as 2',5'-oligoadenylate synthetase (OAS) and protein kinase R (PKR), which inhibit viral replication.
* **Immune modulatory proteins:** such as major histocompatibility complex (MHC) class I and II molecules, which enhance antigen presentation to T cells.
* **Cytokines:** such as chemokines, which attract immune cells to the site of infection.
* **Other proteins:** involved in cell growth, differentiation, and apoptosis.

**6. Feedback Regulation:**
IFN-γ signaling also involves feedback regulation mechanisms. IFN-γ can induce the expression of suppressor of cytokine signaling (SOCS) proteins, which inhibit the JAK-STAT pathway, limiting the duration and intensity of the IFN-γ response.

**Overall, the cellular response to type II interferon is a critical process that orchestrates a multifaceted antiviral and immune response. It involves complex signaling events leading to the activation of numerous genes and proteins, ultimately contributing to the elimination of pathogens and the establishment of protective immunity.**'
"

Proteins (22)

Compounds (471)