CD82 R2, C33, IA4, 4F9
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 3 glycoprotein, 4 span
Fibroblast
T Cell
B Cell
Epithelial Cell
Monocyte
Peripheral blood
Endothelial Cell
Leukocyte
Polymorphonuclear cell
45 / 45
90 / 90

Expression
CD82 is expressed in polymorphonuclear cells and monocytes but has a weaker expression in T and B cells.  Expression appears to be down regulated in all peripheral blood leukocytes during infections.  Epithelial cells, endothelial cells and fibroblasts express CD82. 



Structure
MOLECULAR FAMILY NAME: Belongs to the tetraspanin family.

CD82 is a multi-pass type-3, 4 span 267 aa glycoprotein.  It contains a large hydrophilic extracellular domain which contains 3 putative N-glycoslation sites, 4 putative transmembrane domains, each at least 23 aa, and are separated into 2 unequal extracellular loops, 27aa and 119 aa, and 2 short cytoplasmic sequences containing NH2- and COOH-termini (9 aa and 15 aa). 
 
MOLECULAR MASS
Cell Type Unreduced Reduced Comment
Varied cell types 45-90 kDa Depending on cell type and state of cell activation

CD82 has a calculated Mr = 28 kDa peptide core.

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION

CD82 has 3 N-glycosylation sites in the large extracellular loop.  Digestion with N-glycanase reduced the Mr to 28 kDa with no effect of O-glycanase.

Ligands
Co-immunoprecipitation and flow cytometric energy transfer studies have shown that CD82 associates non-covalently with a number of other molecules like MHC class I and II, CD20, CD37, CD53 and CD81 in B cells, CD4, CD8 and CD81 in T cells, and integrins including CD29/CD49d VLA-4 in some cell lines.  No extracellular ligand has been identified for CD82.

LIGANDS AND MOLECULES ASSOCIATED WITH CD82
Molecule Comment
Other tetraspan molecules
MHC-I
MHC-II
b1 integrins
CD4 Only p56Lck-free CD4
CD8



Function
CD82 functions as an activation antigen of T cells.  CD82 induces signal transduction.  It forms a complex with other members of this family (CD37, CD53 and CD81) as well as integrins and MHC molecules.  CD82 crosslinking promotes activation of human monocytic cell lines. Immobilized anti-CD82 induces T cell spreading, pseudopod formation, modulation of T cell proliferation and provides co-stimulatory signals for cytokine production.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD82 IN INTACT ANIMAL

CD82 has been shown to be downregulated in tumor progression of human cancers and can be activated by p53 through a consensus binding sequence in the promoter.  Its expression and that of p53 are strongly correlated and the loss of expression is associated with poor survival for prostate patients.  CD82 is involved in the prostate tumor metastatic potential.  Transfection of human CD82 inhibits the metastatic potential of prostate cancer cells in rat.  CD82 expression is correlated with the metastatic potential lung, breast, pancreas and colon carcinomas and hepatoma in humans.

Comments
MOLECULAR INTERACTIONS -
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD82: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD82: No information.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 3732P27701
MouseP40237D14883
Antibodies

Revised June 25, 2008


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