Paired immunoglobulin-like type 2 receptor beta is a protein that in humans is encoded by the ''PILRB'' 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 non-ITIM-bearing member of the receptor pair, which has a truncated

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 relative to its ITIM-bearing partner and functions in the activating role.

Alternative splicing Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be ...

has been observed at this locus and three variants, encoding two distinct isoforms, are described. Additional transcript variants have been identified but their full-length nature has not been determined. The mouse homolog of PILRbeta has been studied in mice and found to have one known natural ligand, CD99, though it is unclear if this interaction occurs in the human homologs.

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 ...

, PILRbeta has a truncated

tail compared to PILRalpha and features a charged residue within its transmembrane domain. PILRbeta 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

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 PILRalpha, 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, - ''síalon'') was first introduced by Swedish biochemist Gunnar Blix in 1952. The most common member of this gr ...

References

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