PILRA PILRα (paired immunoglobulin-like type 2 receptor α)
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 1 glycoprotein
Hemopoietic cell
Monocyte
Macrophage
Granulocyte
Dendritic Cell
Tonsil
Blood Cell
50 / 50

Expression
PILRα is expressed predominantly in hemopoietic tissues and is expressed by monocytes, macrophages and granulocytes but not be lymphocytes.  Strong expression is by dendritic cells, preferentially by CD14+/CD1a dendritic cell derived from  CD34+ progenitors.  Expression is also by CD11c+ blood and tonsil dendritic cells but not by CD11c dendritic cell precursors.

Structure
MOLECULAR FAMILY NAME

PILRα is a single-pass type-1 303 aa glycoprotein.  It contains an extracellular domain which contains 1 Ig-like V-type domain and a potential N-linked glycosylation site, a transmembrane domain and a cytoplasmic domain which contains 3 potential tyrosine phosphorylation sites, 2 sites are within the immunoreceptor tyrosine-based inhibitor motif (ITIM) and a non-ITIM site.  Analysis predicted that PILRα does not contain an Ig domain per se, but does contain an Ig-like cysteine-based motif involved in intradomain disulfide bonding.  The motif is involved in modulation of cellular responses.  The phosphorylated ITIM motif can bind the SH2 domain of several SH2 containing phosphatases.

MOLECULAR MASS

POST-TRANSCRIPTIONAL MODIFICATION

Alternative splicing yields 4 different isoforms.  Isoforms1 and 2 are cell membranes and isoforms 3 and 4 are secreted proteins.  The secreted proteins lack transmembrane domains.

POST-TRANSLATIONAL MODIFICATION

PILRα has N- and O-glycoslated sites and is phosphorylated on tyrsine residues.

Ligands
LIGANDS AND MOLECULES ASSOCIATED WITH PILRα: No information.

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.  Control of cell signaling via SHP-1 is thought to occur through a balance between PILRα mediated inhibition and PILRβ mediated activation.  Paired receptors consist of highly related activating and inhibitory receptors and are widely involved in the regulation of the immune system.  PILRα is thought to act as a cellular signaling inhibitory receptor by recruiting cytoplasmic phosphatases like PTPN6/SHP-1 and PTPN11/SHP-2 via their SH2 domains that block signal transduction through dephosphorylation signaling molecules.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF PILRα IN INTACT ANIMAL

The chromosome localization is 7q22 of PILRα is close to a region associated with chromosomal abnormalities in the myelodysplastic syndrome and acute myeloid leukema.



Comments
MOLECULAR INTERACTION-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF PILRα: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY PILRα: No information.

Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrez29992Q9UKJ1
Antibodies

Revised June 25, 2008


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