IFNAR2

Also known as

• Interferon-alpha/beta receptor beta chain
• Interferon Alpha And Beta Receptor Subunit 2
• Interferon (Alpha, Beta And Omega) Receptor 2
• Type I Interferon Receptor 2
• IFNABR

 

Physiology

IFNAR2 is activated by:

• Type I interferons
  
1. IFN-α
2. IFN-β
3. IFN-ε
4. IFN-κ 
5. IFN-ω
• Type III interferons
1. IFN-λ1
2. IFN-λ2
3. IFN-λ3
4. IFN-λ4

 

Molecular actions

1. IFNAR1 (subunit 1) and IFNAR2 (subunit 2) form a cell surface receptor called IFNAR (Interferon-alpha/beta receptor).
2. IFNAR1 associates with the enzyme TYK2. 
3. IFNAR2 associates with the enzyme JAK1.

Interferon signalling

1. IFNAR1 or IFNAR2 binds an IFN to form a binary complex.
2. The interferon-subunit complex recruits the other IFNAR subunit to form a ternary complex.

JAK/STAT signalling

1. JAK1 and TYK2 are brought into close proximity and phosphorylate the 2 IFNAR subunits.
2. IFNAR recruits proteins called STATs (Signal transducer and activator of transcriptions). The STATs are activated by phosphorylation.
   
3. pSTATs form homodimers (e.g. STAT1-STAT1) or heterodimers (e.g. STAT1-STAT2). 
4. pSTAT dimers enter the cell nucleus and bind to the DNA.
5. Transcription is blocked or reduced in some target genes (repression).
6. Transcription is activated in some target genes (expression).

 

Biological functions

• Immunity
  
• Antiviral responses
• Pro-inflammatory responses
  

 

Clinical significance

Disorders associated with IFNAR2 variants include:

• Coronavirus Disease 2019 (COVID-19)
• Pathophysiology
• Measles as a result of MMR vaccination
  
• Severe HHV6 infection
  
• Immunodeficiency 45 (IMD45)

These disorders suggest an increased susceptibility to severe viral infections, possibly due to an interferon signalling deficiency.

 

Protein profile

• Size (amino acids) = 515
• Molecular mass (Daltons) = 57,75
• Quaternary structure: Heterodimer with IFNAR1. Isoform 1 interacts with the transcriptional factors STAT1 and STAT2. IFNAR1 interacts with TYK2. IFNAR2 interacts with JAK1.
• Protein family: Cell surface receptor.

 

Genetic profile

• Species: Human
• Chromosome: 21
• Band: 21q22.11
• Starts at base pair: 33,229,901
• Ends at base pair: 33,265,675
• Sequence length (base pairs): 35,775
  

 

See also

• genecards.org
• Interferon