CD27 TNFRSF7 (tumor necrosis factor receptor superfamily, member 7), S152, T14, Tp55
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Lineage Restricted Molecule
Type 1 glycoprotein
T Cell
Plasma Cell
Thymocyte
NK Cell
B Cell
Blood Cell
Progenitor Cell
Hematopoietic Cell
Stem Cell
Peripheral blood
55 / 55
110 / 110
120 / 120

Expression
CD27 is expressed on hemopoetic stem cells, a majority of peripheral blood T cells, early progenitor cells, preferentially on CD45RA+ T cells after activation, medullary thymocytes and on activated and memory-type B cells.  B-cells acquire CD27 expression in the germinal center and keep on expressing the molecule until the plasma cell stage.  CD27 is also expressed on NK cells.


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

CD27 is a single-pass type-1 disulfide-linked homodimeric 240 aa glycoprotein.  It contains an 171 aa extracellular domain which contains 2 cysteine-rich domains, a membrane-proximal half-TNF receptor domain and a N- and 3 O-glycosylation sites, a 21 aa transmembrane domain and a 48 aa C-terminal cytoplasmic domain containing a serine phosphorylation site but does not contain any known signaling motif.  PIQEDYR motif in the cytoplasmic domain is essential for binding of TNF receptor associated fators TRAF2 and TRAF5.  

MOLECULAR MASS
Cell Type Unreduced Reduced
T lymphocytes 110-120 kDa 5 kDa

POST-TRANSCRIPTIONAL MODIFICATION

CD27 cDNA does not contain a downstream poly A tract, causing the size difference between the cDNA of 1.2 kb and the mRNA of 1.3 kb.

POST-TRANSLATIONAL MODIFICATION

CD27 has 1 N-linked and 3 O-linked glycosylation sites in the extracellular domain.  Soluble CD27 is produced by lymphocytes upon activation, probably due to proteolytic cleavage.  CD27 undergoes serine-phosphorylation in the intracellular cytoplasmic domain.

Ligands
LIGANDS AND MOLECULES ASSOCIATED WITH CD27
Molecule Comment
CD70 Type II transmembrane molecule belonging to the TNF family
SIVA Apoptosis-inducing protein reported but not confirmed independently
TRAF5 Involved in NF-kB and SAPK/JNK activation by CD27
TRAF2 Involved in NF-kB and SAPK/JNK activation by CD27


Function
CD27 is a T cell associated molecule and is important to B cells because it is a ligand for CD70 and is highly expressed on memory B cells.  Ligating CD27 with CD70 drives memory B cells to become plasma cells.  CD27 mediates a co-stimulatory signal for T and B cell activation and is involved in murine T cell development.  Cells expressing CD70 can interact via CD27 to co-stimulate T cell proliferation, regulates differentiation of effector cells, generates cytotoxic T cells and enhance cytokine production.  CD70 binding to CD27 on B cells, co-stimulates B cell proliferation and immunoglobulin production.  Triggering on murine hematopoietic stem cells and early progenitors by CD70 inhibits differentiation to leukocytes.  Knockout mice have normal overall hematopoiesis but have increased numbers of leukocytes, particularily B cells, and display impaired T cell responses after antigenic challenge.  CD27 is involved in activation of NF-κB and stress-activated protein kinase (SAPK)/cJun N-terminal kinase (JNK).   

BIOCHEMICAL ACTIVITY

CD27 is phosphorylated on serine residues and hyperphosphorylated with T cell activation.   Tyrosine-phosphorylation of ZAP-70 following CD27 ligation of T cells has been reported, but not confirmed independently.

DISEASE RELEVANCE AND FUNCTION OF CD27 IN INTACT ANIMAL

Levels of soluble CD27 in biological fluids increase in patients suffering from a variety of immunopathological diseases as a marker for T cell activation in vivo.

Comments
MOLECULAR INTERACTIONS -
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD27
Molecule Comment
SP-1 Transcription regulation
AP2 Transcription regulation
c-myb Transcription regulation
c-myc Transcription regulation
Butyrate-responsive element (BRE) Transcription regulation
HNF-1 Transcription regulation
NF-kB Transcription regulation

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD27: No information.

ADDITIONAL INSIGHTS

CD27/CD70 interactions regulate B cell proliferation and differentiation by T cells, in addition to T cell activation.

Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 939P26842
MouseA49053P41272L24495
Antibodies
LT27   View Reactivity
M-T271   View Reactivity

Revised June 25, 2008


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