CD85a ILT5 (immumoglobulin-like transcript-5), LIR3 (immunoglobulin-like receptor-3), LILRB3 (leukocyte immunolglobulin-like receptor, subfamily B with TM and ITIM domains, member 3), HL9
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 1 glycoprotein
Monocyte
Macrophage
NK Cell
Dendritic Cell
Granulocyte
T Cell
110 / 110

Expression
CD85a is expressed on monocytes, macrophages, NK cells, dendritic cells, granulocytes and a subpopulation of T cell.  There is weak expression on Lin-HLA-DR+CD11c fresh and cultured blood dendritic cells.  MoDC express CD85a molecules and there appears to be no change in expression levels following activation of the MoDC with activating agents.  In vitro generated dendritic cells derived from CD34+ cells weakly express CD85a.  Migrating epidermal and dermal cells exhibit low levels of expression.



Structure
MOLECULAR FAMILY NAME: Belongs to the immunoglobulin supergene family.

CD85a is a single-pass type-1 glycoprotein.  It contains a 608 aa extracellular domain which contains 4 Ig-like C2-type domains, a 21 aa transmembrane and a long 167 aa cytoplasmic domain containing 3 ITIM motifs and is involved in the suppression of NK-mediated cytotoxicity.  The ILT/LIR family belongs to the Ig gene superfamily.

MOLECULAR MASS

POST-TRANSCRIPTIONAL MODIFICATION:

Alternative splicing yields 2 different isoforms.

POST-TRANSLATIONAL MODIFICATION:

CD85a has 4 N-glycosylation sites.



Ligands
LIGANDS AND MOLECULES ASSOCIATED WITH CD85a:

CD85a binds to MHC class I.


Function
CD85a is involved in the activation of NK-mediated cytotoxicity and is an inhibitory receptor for MHC class I molecules.  Cytoplasmic ITIMs recruit and activate protein tyrosine phosphatases SHP-1 and/or SHP-2 that act as inhibitory signaling effector molecules.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD85a IN INTACT ANIMAL: No information.



Comments
Previously, the ILT family was clustered together as CD85.  Recently subclassifications have been given to individual members listed as CD85a - CD85m.  Ig-like transcripts (ITLs) and leukocyte Ig-like transcripts (LIRs) are structurally and functionally related transmembrane glycoproteins.  The receptors are divided into 2 groups of inhibitory and activating receptors according to the nature of their transmembrane and cytoplasmic regions.  Receptors with a long cytoplasmic tail, CD85a (ILT5/LIR3), CD85c (LIR8), CD85d (ILT4/LIR2), CD85j (ILT2/LIR1) and CD85k (ILT3/LIR5), contain one or more intracytoplasmic ITIMs which recruit and activate protein tyrosine phosphates SHP-1 and/or SHP-2.  Receptors with a short tail, CD85b (ILT8), CD85f (ILT11), CD85g (ILT7), CD85h (ILT1/LIR7) and CD85i (LIR6a) lack ITIMs and contain a positively charged aa residue, arginine or lysine, in their transmembrane domain which is necessary for association with ITIM-containing polypeptides like FcRg chain.  CD85l (ILT9) and CD85m (ILT10) bind the FcRg chain.  Phosphorylated ITAMs recruit the protein tyrosine kinases Syk and ZAP70.  One exception to these transmembrane receptors is CD85e (ILT6/LIR4) which has no transmembrane or cytoplasmic domains and is probably soluble.                     

MOLECULAR INTERACTIONS -
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD85a: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD85a: No information.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene11025O75022
Antibodies

Revised June 25, 2008


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