59 kDa 2'-5'-oligoadenylate synthetase-like protein is an
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
that in humans is encoded by the ''OASL''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
2'-5'-oligoadenylate synthase
In molecular biology, 2'-5'-oligoadenylate synthetase (2-5A synthetase) is an enzyme () that reacts to interferon signal. It is an antiviral enzyme that counteracts virus, viral attack by degrading RNAs, both viral and host. The enzyme uses Adenosi ...
is a protein family of structurally similar proteins, including
OAS1,
OAS2, and
OAS3
2'-5'-oligoadenylate synthetase 3 is an enzyme that in humans is encoded by the ''OAS3'' gene.
This gene encodes an enzyme included in the 2', 5' oligoadenylate synthase family. This enzyme is induced by interferons and catalyzes the 2', 5' ol ...
. However, mutations in the OAS domain mean it lacks the motif to allow oligomerization, preventing the synthesis of oligoadenylates. OASL, like the proteins of 2'-5'-oligoadenylate synthase family, is induced by
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 ...
s.
Function
RNA Virus Infection
In RNA virus infection, viral genetic material binds to the RNA sensor
RIG-I
RIG-I (retinoic acid-inducible gene I) is a cytosolic pattern recognition receptor (PRR) that can mediate induction of a type-I interferon (IFN1) response. RIG-I is an essential molecule in the innate immune system for recognizing cells that ...
, triggering a reaction cascade that culminates in the secretion of type I interferons.
OASL acts as a sensitiser of RIG-I, binding to the
caspase activation and recruitment domain and enhancing interferon production.
[ ]
DNA Virus Infection
While OASL has an anti-viral role in RNA viral infection, it has also demonstrated a pro-viral role in DNA viral infection.
OASL can bind to the viral DNA sensor
cGAS, inhibiting its catalytic activity and preventing the secretion of interferons.
Intracellular Bacterial Infection
OASL is shown to be upregulated during a wide variety of vacuolar and cytosolic bacterial infections.
[ ] It possesses an ability to inhibit
autophagic
Autophagy (or autophagocytosis; from the Greek , , meaning "self-devouring" and , , meaning "hollow") is the natural, conserved degradation of the cell that removes unnecessary or dysfunctional components through a lysosome-dependent regulated ...
mechanisms and
antimicrobial peptide
Antimicrobial peptides (AMPs), also called host defence peptides (HDPs) are part of the innate immune response found among all classes of life. Fundamental differences exist between prokaryotic and eukaryotic cells that may represent targets for ...
secretion within the host cell through unclear mechanisms, preventing clearance of the pathogen and creating a favourable intracellular environment.
[ ]
See also
*
Oasl2, a mouse gene, which is a
paralog
Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a sp ...
of mouse gene Oasl1, the
ortholog
Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a speci ...
of this gene
References
Further reading
*
*
*
*
*
*
*
*
*
{{PDB Gallery, geneid=8638