CD313 EMR3 (epidermal growth factor-like module containing, mucin-like, hormone receptor-like 3)
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 3 glycoprotein, 7 span
Leukocyte
Peripheral blood
Neutrophil
Spleen
Lung

Expression

CD313 is highly expressed predominantly on leukocytes and neutrophils but is weaker monocytes and macrophages.  Expression is strong in spleen, peripheral blood and lung, with intermediate levels in placenta and bone marrow.  Expression is low in heart, kidney liver, pancreas, skeletal muscle, lymph node, thymus, tonsil and fetal liver and no expression in the brain.



Structure
MOLECULAR FAMILY NAME: Belongs to the G-protein coupled receptor 2 family.

CD313 is a multi-pass type-3 7-span 631 aa glycoprotein.  It contains a 21 aa signal sequence, a 336 aa extended extracellular domain which contains a N-terminal non-Ca++ binding EGF-like domain followed by a single Ca++ binding EGF-like module.  The EGF-like modules followed by a  232 aa spacer domain which is serine- and threonine-rich and contains a G-protein-coupled receptor proteolytic (GPS).  The serine/threonine-rich region has the potential to be heavily O-glycosylated whikch would make this domain a rigid stalk-like structure.  CD313 contains a 7-span transmembrane domain and a C-terminal cytoplasmic domain.  The TM domain has approximately 90% sequence identity to CD312.  CD313 also contains a putative GPCR proteolytic site and a TM7 region.

MOLECULAR MASS

POST-TRANSCRIPTIONAL MODIFICATION

Alternative splicing yields 3 different isoforms.  The isoforms arise from alternative RNA splicing have been described including a soluble form comprising only the 2 EGF-like domains.

POST-TRANSLATIONAL MODIFICATION

CD313 is predicted to be proteolytically cleaved into 2 subunits.  The α subunit is in the N-terminal extracellular EGF-domains and the second subunit is located in the 7-span transmembrane domain.  The subunits form a heterodimer noncovalently linked via an extended spacer domain.


Ligands
LIGANDS AND MOLECULE ASSOCIATED WITH CD313

An unidentified ligand for CD313 is expressed by monocyte-derived macrophages and neutrophils.

Function
CD313, a member of the TM7 receptor family, is expressed predominantly by cells of the immune system.  The function of CD313 is currently unknown but it is probably involved in myeloid-myeloid interactions during immune and inflammatory responses.  Flow cytometric screening demonstrated that CD313, not CD312, interacts with monocyte-derived macrophages and neutrophils activated with fMLP but not with CD55, the CD97 ligand.  It is noted that CD313 and CD312 share a high degree of sequence indentity in the TM domains but not in the extracellular domains, whereas CD313 and CD97 are highly homologous in the EGF-like domains but not in the transmembrane domains, suggesting different ligand-binding and intracellular signaling activities.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD313 IN INTACT ANIMAL: No information.

Comments
MOLECULAR INTERACTIONS-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD313: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD313: No information.

Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene84658Q9BY15
Antibodies

Revised June 25, 2008


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