Paired immunoglobin like type 2 receptor alpha is a
protein that in
humans is encoded by the PILRA
gene.
[
]
Function
Cell signaling pathways rely on a dynamic interaction between activating and inhibiting processes.
SHP-1-mediated
dephosphorylation of protein
tyrosine residues is central to the regulation of several cell signaling pathways. Two types of inhibitory receptor superfamily members are
immunoreceptor tyrosine-based inhibitory motif (ITIM)-bearing receptors and their non-ITIM-bearing, activating counterparts.
Control of cell signaling via SHP-1 is thought to occur through a balance between PILRalpha-mediated inhibition and
PILRbeta-mediated activation. These paired
immunoglobulin
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
-like receptor genes are located in a tandem head-to-tail orientation on
chromosome 7. This particular gene encodes the ITIM-bearing member of the receptor pair, which functions in the inhibitory role. Alternative
splicing has been observed at this
locus, and three variants, each encoding a distinct
isoform, are described.
In contrast to PILRbeta, which has only one known natural ligand, PILRalpha has many known
protein-protein interactions.
PILRalpha recruits
PTPN6 and
PTPN1
Tyrosine-protein phosphatase non-receptor type 1 also known as protein-tyrosine phosphatase 1B (PTP1B) is an enzyme that is the founding member of the protein tyrosine phosphatase (PTP) family. In humans it is encoded by the ''PTPN1'' gene. PTP1B i ...
via interactions of its
ITIM
''Itim'' (Filipino for "black"), released overseas as ''The Rites of May'', is a 1976 Filipino thriller film and the directorial debut of Mike de Leon, with a screenplay by Clodualdo del Mundo Jr. and Gil Quito. The film stars Tommy Abuel as ...
motifs.
PILRalpha is also used by some
viruses, notably
HSV-1
Herpes simplex virus 1 and 2 (HSV-1 and HSV-2), also known by their taxonomical names ''Human alphaherpesvirus 1'' and '' Human alphaherpesvirus 2'', are two members of the human ''Herpesviridae'' family, a set of viruses that produce viral inf ...
, for cell entry.
Structure
As with other
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 ...
, PILRalpha has a longer
cytoplasmic
In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. Th ...
tail compared to PILRbeta and features two intracellular
ITIM
''Itim'' (Filipino for "black"), released overseas as ''The Rites of May'', is a 1976 Filipino thriller film and the directorial debut of Mike de Leon, with a screenplay by Clodualdo del Mundo Jr. and Gil Quito. The film stars Tommy Abuel as ...
motifs.
PILRalpha has an extracellular
domain
Domain may refer to:
Mathematics
*Domain of a function, the set of input values for which the (total) function is defined
**Domain of definition of a partial function
**Natural domain of a partial function
**Domain of holomorphy of a function
* Do ...
with a
siglec-like
immunoglobulin
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
fold
Fold, folding or foldable may refer to:
Arts, entertainment, and media
* ''Fold'' (album), the debut release by Australian rock band Epicure
*Fold (poker), in the game of poker, to discard one's hand and forfeit interest in the current pot
*Above ...
that substitutes
hydrophobic interactions for the siglec fold's characteristic
disulfide bond. The structure of this domain is very similar to that of PILRbeta, but the two proteins nevertheless have different
binding affinities
In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. The etymology stems from ''ligare'', which means 'to bind'. In protein-ligand binding, the ligand is usually a m ...
for
sialic acid Sialic acids are a class of alpha-keto acid sugars with a nine-carbon backbone.
The term "sialic acid" (from the Greek for saliva, - ''sÃalon'') was first introduced by Swedish biochemist Gunnar Blix in 1952. The most common member of this gr ...
.
References
Further reading
*
*
*
*
*
*
*
*
*
{{gene-7-stub