Killer cell lectin-like receptor subfamily G member 1 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 ''KLRG1''
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 ...
.
Function
Natural killer (NK) cells are
lymphocyte
A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic ad ...
s that can mediate lysis of certain tumor cells and virus-infected cells without previous activation. They can also regulate specific humoral and cell-mediated immunity. The protein encoded by this gene belongs to the killer cell lectin-like receptor (KLR) family, which is a group of transmembrane proteins preferentially expressed in NK cells. Studies in mice suggested that the expression of this gene may be regulated by MHC class I molecules.
KLRG1 is a lymphocyte co-inhibitory, or immune checkpoint, receptor expressed predominantly on late-differentiated effector and effector memory CD8+ T and NK cells. Its ligands are
E-cadherin
Cadherin-1 or Epithelial cadherin (E-cadherin), (not to be confused with the APC/C activator protein CDH1) is a protein that in humans is encoded by the ''CDH1'' gene. Mutations are correlated with gastric, breast, colorectal, thyroid, and ovarian ...
and
N-cadherin
Cadherin-2 also known as Neural cadherin (N-cadherin), is a protein that in humans is encoded by the ''CDH2'' gene. CDH2 has also been designated as CD325 (cluster of differentiation 325).
Cadherin-2 is a transmembrane protein expressed in multipl ...
with similar affinities,
respective markers of epithelial and mesenchymal cells.
Targeting of other co-inhibitory receptors for applications in oncology has gained widespread interest
(e.g., CTLA-4, PD-1, and its ligand PD-L1). Unlike the obvious enhanced immune activation present in CTLA-4 and PD-1 gene knockout mice,
KLRG1 knockout mice initially were found to have no abnormal features,
though were subsequently found to have enhanced immunity in a tuberculosis challenge model.
The characterization of KLRG1 as a “senescent” marker, but other co-inhibitory receptors as “exhaustion” markers,
has contributed to relatively fewer studies on this molecule.
References
Further reading
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External links
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