CD39 ENTPD1 (ectonucleoside triphosphate diphosphohydrolase 1), Ecto-apyrase, gp80, E-ATPase, NTPDase-1, EC3.6.1.5
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Lineage Restricted Molecule
Type 3 glycoprotein, 2 span
Neuron
T Cell
NK Cell
Macrophage
Dendritic Cell
Platelet
Lymphocyte
B Cell
Monocyte
Langerhans Cell
Endothelial Cell
Placenta
78 / 78

Expression
CD39 is not expressed on resting lymphoid cells.  CD39 expression on lymphoid tissues is limited to the mantle zone B cells, activated T cells, NK cells, neurons, platelets, endothelial tissues,  paracortical lymphocytes, macrophages, dendritic cells and Langerhans cells and is absent from germinal centers.  CD39 is expressed in both placenta and umbilical vein.

Structure
MOLECULAR FAMILY NAME:  Belongs to the ecto-apyrase family.

CD39 is a multi-pass type-3, 2 span glycoprotein.  It contains a large extracellular domain which contains an enzymatic site and 7 potential N-glycosylation sites which are important for formation of a functional molecule, 2 transmembrane domains near the N- and C-terminal ends and a short N- and C-terminal cytoplasmic tails.  Mutations of the N-glycosylation sites indicate that glycosylation is important for formation of a functional molecule.  CD39 has 5 highly conserved regions characteristic of the ecto-apyrase family called apyrase conserved regions (ACR).  ACR 1-4 share similarity with the β- and γ-phosphate binding domains of cytoplasmic ATPase superfamily.  Mutations in ACRs lead to the loss of enzymatic activity, whereas mutations in other residues can change the nucleotide specificity of the isoform.  The formation of oligomers in the plasma membrane is essential for enzyme activity.  The 2 transmembrane domains, (TM1 and TM2), are helical and appear to interact with each other and with transmembrane regions of other CD39 molecules.

MOLECULAR MASS
Cell Type Unreduced Reduced
78 kDa

POST-TRANSCRIPTIONAL MODIFICATION

Alternative splicing yields 3 different isoforms.

POST-TRANSLATIONAL MODIFICATION: No information.



Ligands
LIGANDS AND MOLECULES ASSOCIATED WITH CD39: No information.


Function
CD39 is a cation-dependent enzyme that hydrolyses ATP and ADP equally and other di- and tri-phosphate nucleosides.  The primary sequence of CD39 contains 4 segments that are characteristic of ecto-apyrase from plants and yeast and the transfection of CD39 cDNA into COS cells which induces ecto-apyrase activity.  ATP, which leaks from damaged cells such as lysed target cells, could be toxic to the lymphocytes.  Molecules such as CD39 may protect activated lymphocytes through hydrolysis of extracellular ATP.  CD39 can mediate B cell homotypic adhesion.  Thrombin deactivates CD39 on endothelial cells.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD39 IN INTACT ANIMAL

Hydrolysis of ATP and ADP inhibits inflammation and thrombotic responses on endothelial cells and soluble CD39 can prevent ADP-induced platelet aggregation.  In the nervous system, CD39 hydrolyzes ATP and other nucleotides to regulate purinergic neurotransmission.  Knockout mice gave a prolonged bleeding times and CD39 could be implicated in the prevention of platelet aggregation.            

Comments
MOLECULAR INTERACTION-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD39: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD39: No information.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 953P49961
Antibodies
A1   View Reactivity
TU66   View Reactivity

Revised June 25, 2008


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