CD307 FCRL5(Fc receptor-like 5), IRTA2, FcRHS, BXMAS1
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 1 glycoprotein
B Cell
B Lymphocyte
Centroblast
Immunoblast
Tonsil
Small intestine
Spleen
Lymphoma Cell
Lymph Node
Bone Marrow
100 / 100

Expression
CD307 is expressed selectively in B lymphocytes and in particular centrocytes of the germinal center light zone and intraephithelial and interfollicular B cells.  Expression is also is  expressed in marginal zone B cells, immunoblasts and tonsillar germinal center centrocytes.   Expression is in many B lymphoma cell lines and on hairy cell leukemia cells.  Isoforms 1, 3, 4 and 5 are detected in lymph node, spleen, bone marrow and small intestine with preponderance of isoform 3.

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

CD307 is a single-pass type-1 glycoprotein.  It contains 3 major mRNA isoforms which encode a common amino acid sequence up to 560 aa and include a  common signal 
sequence and 6 extracellular Ig-type domains.   Isoform 1 (IRTA2A) is a 759 aa secreted glycoprotein with 8 extracellular Ig-type domains followed by 13 unique polar residues at its C terminus and is secreted.  Isoform 2 (IRTA2B) has 6 extracellular Ig-like domains and after the common 560 aa it has an additional 32 aa whose hydrophobicity is compatibile with its docking to the plasma membrane via a GPI anchor and is GPI-linked to the membrane.  The 977 aa isoform 3 (IRTA2C) has 8 extracellular Ig-like domains which has 8 potential N-linked glycosylation sites, a 23 aa transmembrane region and 104 aa cytoplasmic domain with 2 ITIM consensus sequences encoded by separate exons and shares the first 746 aa with isoform 1.  Isoform 4 (IRTA2D) encodes a 152 aa peptide.  CD307 is a cell surface receptor, which is homologous to the Fc and inhibitory receptor families.  
   
MOLECULAR MASS

POST-TRANSCRIPTIONAL MODIFICATION

Alternative splicing yields 5 different isoforms.

POST-TRANSLATIONAL MODIFICATION: No information.

Ligands
LIGANDS AND MOLECULE ASSOCIATED WITH CD307

Isoform 3 (IRTA2C) bind heat aggregated human IgG (and presumably antigen complexed IgG) with greater affinity for IgG1 than IgG2 but not monomeric IgG, IgA, IgM and IgE.

Function
The structural features of CD307 novel immunoreceptor isoforms suggest a role in regulating B-cell activation, development and differentiation in peripheral lymphoid organs.  However, the function of this molecule has yet to be demonstrated.  It may be a useful marker of B cell stages and may have an immunoregulator role in marginal zone B cells.     

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD307 IN INTACT ANIMAL

CD307 is a B-cell subtype specific marker and is a potential target for immunotherapy in the treatment of B-cell lymphomas (non-Hodgkin's and Burkitt's) and hairy cell leukemia.  In B cell malignancies carrying 1q21 abnormalities, CD307 gene espression is ofter deregulated and is possibly involved  in the translocation of some lymphomas, lymphomagenesis and neoplasia. 


Comments
MOLECULAR INTERACTIONS-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD307: No information.

SUBSTRATES: No information.

ENZYMES WHICH  MODIFY CD307: No information.

ADDITIONAL INSIGHTS

For further information see Hatzivassiliou, G.; et al (2001) Immunity 14: 277-289.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene83416Q96RD9
Antibodies

Revised June 25, 2008


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