Interferon regulatory factor 5 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
that in humans is encoded by the ''IRF5''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
The IRF family is a group of transcription factors that are involved in signaling for virus responses in mammals along with regulation of certain cellular functions.
Function
IRF5 is a member of the
interferon regulatory factor
Interferon regulatory factors (IRF) are proteins which regulate transcription of interferons (see regulation of gene expression). Interferon regulatory factors contain a conserved N-terminal region of about 120 amino acids, which folds into a s ...
(IRF) family, a group of
transcription factor
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The fu ...
s with diverse roles, including virus-mediated activation of interferon, and modulation of cell growth, differentiation, apoptosis, and immune system activity. Members of the IRF family are characterized by a conserved
N-terminal
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...
DNA-binding domain
A DNA-binding domain (DBD) is an independently folded protein domain that contains at least one structural motif that recognizes double- or single-stranded DNA. A DBD can recognize a specific DNA sequence (a recognition sequence) or have a gener ...
containing
tryptophan
Tryptophan (symbol Trp or W)
is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α- carboxylic acid group, and a side chain indole, making it a polar molecule with a non-polar aromatic ...
(W) repeats. Alternative splice variants encoding different isoforms exist.
The regulatory and repression regions of the IRF family are mainly located in the C-terminal of the IRF.
A 2020 study showed that an adaptor protein named TASL play an important regulatory role in IRF5 activation by being phosphorylated at the pLxIS motif, drawing a similar analogy to the
IRF3
Interferon regulatory factor 3, also known as IRF3, is an interferon regulatory factor.
Function
IRF3 is a member of the interferon regulatory transcription factor (IRF) family. IRF3 was originally discovered as a homolog of IRF1 and IRF2. ...
activation pathway through the adaptor proteins MAVS, STING and TRIF.
Clinical significance
IRF5 acts as a molecular switch that controls whether
macrophage
Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer cel ...
s will promote or inhibit inflammation. Blocking the production of IRF5 in macrophages may help treat a wide range of autoimmune diseases, and that boosting IRF5 levels might help treat people whose immune systems are weak, compromised, or damaged. IRF5 seems to work "either by interacting with DNA directly, or by interacting with other proteins that themselves control which genes are switched on."
Signaling
The IRF family regulates the gene expression for the
interferon
Interferons (IFNs, ) are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten the ...
(IFN) response to viral infections.
IRF5 is a direct transducer to interferon signaling and is activated via phosphorylation. The IRF family can also initiate the
JAK/STAT signaling pathway by binding to transmembrane receptors that activate JAK. IRFs, IFNs, and the JAK/STAT signaling pathway work together to fight viral infections in mammals through specific signals.
See also
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Interferon regulatory factors
Interferon regulatory factors (IRF) are proteins which regulate transcription of interferons (see regulation of gene expression). Interferon regulatory factors contain a conserved N-terminal region of about 120 amino acids, which folds into a st ...
References
Further reading
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External links
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Transcription factors
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