The leukocyte immunoglobulin-like receptors (LILR) are a
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
of
receptors
Receptor may refer to:
*Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse
*Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a n ...
possessing extracellular
immunoglobulin domains
The immunoglobulin domain, also known as the immunoglobulin fold, is a type of protein domain that consists of a 2-layer sandwich of 7-9 antiparallel β-strands arranged in two β-sheets with a Greek key topology, consisting of about 125 amino ac ...
.
They are also known as
CD85, ILTs and LIR, and can exert immunomodulatory effects on a wide range of immune cells.
[Damian Brown, Rachel L Allen, & John Trowsdale. The LILR family: modulators of innate and adaptive immune pathways in health and disease. Tissue Antigens (2004) 64:215 http://onlinelibrary.wiley.com/doi/10.1111/j.0001-2815.2004.00290.x/pdf] The human genes encoding these receptors are found in a
gene cluster
A gene family is a set of homologous genes within one organism. A gene cluster is a group of two or more genes found within an organism's DNA that encode similar polypeptides, or proteins, which collectively share a generalized function and are o ...
at chromosomal region 19q13.4.
They include
*
LILRA1
Leukocyte immunoglobulin-like receptor, subfamily A (with TM domain), member 1 is a protein that in humans is encoded by the ''LILRA1'' gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the M ...
*
LILRA2
*
LILRA3
Leukocyte immunoglobulin-like receptor subfamily A member 3 (LILR-A3) also known as CD85 antigen-like family member E (CD85e), immunoglobulin-like transcript 6 (ILT-6), and leukocyte immunoglobulin-like receptor 4 (LIR-4) is a protein that in huma ...
*
LILRA4
*
LILRA5
*
LILRA6
*
LILRB1
Leukocyte immunoglobulin-like receptor subfamily B member 1 is a protein that in humans is encoded by the ''LILRB1'' gene.
Function
This gene is a member of the leukocyte immunoglobulin-like receptor (LIR) family, which is found in a gene clu ...
*
LILRB2
Leukocyte immunoglobulin-like receptor subfamily B member 2 is a protein that in humans is encoded by the ''LILRB2'' gene.
This gene is a member of the leukocyte immunoglobulin-like receptor (LIR) family, which is found in a gene cluster at chr ...
*
LILRB3
Leukocyte immunoglobulin-like receptor subfamily B member 3 is a protein that in humans is encoded by the ''LILRB3'' gene.
This gene is a member of the leukocyte immunoglobulin-like receptor (LIR) family, which is found in a gene cluster at chrom ...
*
LILRB4
*
LILRB5
Leukocyte immunoglobulin-like receptor subfamily B member 5 is a protein that in humans is encoded by the ''LILRB5'' gene.
This gene is a member of the leukocyte immunoglobulin-like receptor
The leukocyte immunoglobulin-like receptors (LILR) ar ...
* LILRB6 or
LILRA6
* LILRB7 or
LILRA5
A subset of LILR recognise
MHC class I (also known as
HLA class I in humans). The LILR family is a cluster of
paired receptors
Paired receptors are pairs or clusters of receptor proteins that bind to extracellular ligands but have opposing activating and inhibitory signaling effects. Traditionally, paired receptors are defined as homologous pairs with similar extracell ...
with both activating and inhibitory functions.
Of these, the inhibitory receptors
LILRB1
Leukocyte immunoglobulin-like receptor subfamily B member 1 is a protein that in humans is encoded by the ''LILRB1'' gene.
Function
This gene is a member of the leukocyte immunoglobulin-like receptor (LIR) family, which is found in a gene clu ...
and
LILRB2
Leukocyte immunoglobulin-like receptor subfamily B member 2 is a protein that in humans is encoded by the ''LILRB2'' gene.
This gene is a member of the leukocyte immunoglobulin-like receptor (LIR) family, which is found in a gene cluster at chr ...
show a broad specificity for classical and non-classical MHC alleles with preferential binding to
b2m-associated complexes. In contrast, the activating receptors LILRA1 and
LILRA3
Leukocyte immunoglobulin-like receptor subfamily A member 3 (LILR-A3) also known as CD85 antigen-like family member E (CD85e), immunoglobulin-like transcript 6 (ILT-6), and leukocyte immunoglobulin-like receptor 4 (LIR-4) is a protein that in huma ...
prefer b2m-independent free heavy chains of MHC class I, and in particular
HLA-C
HLA-C belongs to the MHC (human = HLA) class I heavy chain receptors. The C receptor is a heterodimer consisting of a HLA-C mature gene product and β2-microglobulin. The mature C chain is anchored in the membrane. MHC Class I molecules, like HLA ...
alleles.
See also
*
LAIR1
Leukocyte-associated immunoglobulin-like receptor 1 is a protein that in humans is encoded by the ''LAIR1'' gene. LAIR1 has also been designated as CD305 (cluster of differentiation 305).
Function
The protein encoded by this gene is an inhibit ...
*
Killer-cell immunoglobulin-like receptor
Killer-cell immunoglobulin-like receptors (KIRs), are a family of type I transmembrane glycoproteins expressed on the plasma membrane of natural killer (NK) cells and a minority of T cells. At least 15 genes and 2 pseudogenes encoding KIR map ...
References
Immunoglobulin superfamily
{{immunology-stub