CD267 TNFRSF13B (tumor necrosis factor receptor superfamily, member 13B), TACI
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 3 glycoprotein
B Cell
Leukemia cell
Myeloma
Spleen
Thymus
Small intestine
Leukocyte
Peripheral blood
32 / 32

Expression
CD267 is expressed on myeloma cells and on B cells, predominantly CD27+ memory B cells.  High expression is in spleen, thymus, small intestine and peripheral blood leukocytes.  Expression is also in resting B cells and activated T cells but there are conflicting reports wheither activated T cells are expressed on CD267 and there is no expression in resting T cells.  Expression is not found in heart, brain, placenta, lung, liver, skeletal muscle, kidney or pancreas.  Expression has been detected on multiple myeloma cells and B cell chronic lymphocytic leukemia (B-CLL).

Structure
MOLECULAR FAMILY NAME: Belongs to the tumor necrosis factor receptor family.

CD267 is a single-pass type-3 293 aa glycoprotein.  It contains an 165 aa extracellular domain which contains 2 TNFR cysteine-rich repeats and a potential N-linked glycosylation site, a 21 aa transmembrane domain and an 107 aa cytoplasmic domain.  The protein is a lymphocyte-specific member of the TNF receptor superfamily. 

MOLECULAR MASS

POST-TRANSCRIPTIONAL MODIFICATION

Alternative splicing yields 2 different isoforms.  The shorter isoform lacks one TNFR-Cys repeat but has been shown to retain its ligand binding capability.

POST-TRANSLATIONAL MODIFICATION: No information.

Ligands
LIGANDS AND MOLECULE ASSOCIATED WITH CD267

CD267 binds CD257 (TALL1) and CD256 (TALL2) with high affinity.

Function
CD267 is the receptor for CD257 (TALL1) and CD256 (TALL2).  CD267 interacts with calcium-modulator and cyclophilin ligand (CAML).  The protein induces activation of the transcription factors NFAT, AP1 and NF-κB and plays a crucial role in humoral immunity by interacting with a TNF ligand and is involved in the stimulation of T cell function.  CD267-deficient mice have normal B-cell development but B cell homeostatis and tolerance is impaired resulting in autoimmunity and the development of lymphomas.  Specific activation of CD267 in a human B cell line induced apoptosis suggesting that CD267 is a negative regulator of B cell activation.  T-independent type 2 response is almost abolished in CD267-/- mice, indicating CD267 provides an essential costimulatory signal for T-independent humoral responses.  Mutations in CD267 are associated with common variable immunodeficiency and IgA deficiency in humans.  However in contrast to CD267-/- mice, lymphoroliferation and autoimmunity are not common features of CD267 deficiency in humans.

BIOCHEMICAL ACTIVITY: No information:

DISEASE RELEVANCE AND FUNCTION OF CD267

Agonistic antibody to CD267 is a potential therapeutic agent in the treatment of B cell lymphoproliferative disorders.  CD267-Ig is being trialed as a decoy receptor for BAFF in the treatment of B cell malignancies and autoimmune disorders.  Defects in CD267 are a cause of common variable immunodeficiency (CVID) and immunoglobulin A deficiency (IGAG1).  These diseases are known to coexist.  Individuals having IGAD1 later can develop CVID suggesting that some of these cases may have a  common etiology.

Comments
MOLECULAR INTERACTIONS-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD267: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD267: No information.

ADDITIONAL INSIGHTS

For further information see Xia, X. Z. et al (2000) J, Exp. Med. 192: 137-143.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene23495014836
Antibodies

Revised June 25, 2008


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