CD321 JAM-1 (junctional adhesion molecule 1), F11
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 1 glycoprotein
Epithelial Cell
Endothelial Cell
Leukocyte
Platelet
Erythrocyte
Neutrophil
Monocyte
Lymphocyte
Lung
Kidney
Placenta
Tongue
32 / 32
35 / 35

Expression
CD321 is expressed on broad cells, on endothelial, epithelial cells, erythrocytes and leukocytes.  Among leukocytes it is expressed on neutrophils, monocytes and lymphocytes.  Expression is also found in several tissues such as lung, kidney, placenta, blood leukocytes and platelets. 

Structure

MOLECULAR FAMILY NAME:  Belongs to the immunoglobulin gene family.

CD321 is a single-pass type-1 299 aa glycoprotein.  It contains a 210 aa extracellular domain which contains 2 Ig-like V-type domains, an Ig-like C2-type domain and 1 potential N-linked glycosphorylation site, a 19 aa transmembrane domain and a 38 aa cytoplasmic domain which contains 2 tyrosines and several phosphorylation sites.  CD321 is the receptor for the platelet-activating antibody F11.   X-ray crystallography indicates that CD321 dimerizes, forming a U-shaped dimer.  Functional analysis suggests that physiologically dimers form between CD321 molecules on interacting cells rather than on the same cell.

MOLECULAR MASS

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION

CD321 has a N-linked glycosylation site.



Ligands
LIGANDS AND MOLECULE ASSOCIATED WITH CD321

CD321 appears to interact with CD321 on interacting cells in forming tight junctions.  CD321 is also a ligand for LFA-1 and binds reoviruses. 
 


Function
CD321 is an adhesion molecule that is involved in the formation of tight junctions between cells and is involved in platelet aggregation.  The exact mechanisms are unknown, and tight junctions are complex regions invovling the assembly of several different molecules.  Tight junctions represent one mode of cell-to-cell adhesion in epithelial or endothelial cell sheets, forming continuous seals around cells and serving as a physical barrier to prevent solutes and water from passing freely through the paracellular space.  The protein encoded by this immunoglobulin superfamily gene member, CD321, is an important regulator of tight junction assembly in epithelia.  The N-terminal extracellular domain of CD321 (JAM-1) interacts with the corresponding domain of CD321 with tight junction components through binding motifs on the cytoplasmic domain.  CD321 appears to have a role in extravasation of leukocytes, an importnat process in inflammation and immunity.  It plays a role in regulating monocyte transmigration involved in the integrity of epithelial barrier regulates leukocyte transmission and is involved in platelet activation.  In addition, the encoded protein can act as 1) a receptor for reoviruses 2) a ligand for the integrin LFA1, involved in leukocyte transmigration having an important process in inflammation and immunity, and 3) a platelet receptor. 


BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD321 IN INTACT ANIMAL

Currently CD321 gas research reagents with potential value in immunophenotypic analysis.

Comments
MOLECULAR INERACTIONS-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD321: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD321: No information.

ADDITIONAL INSIGHTS

For further information see Sobocka, M. B. et al (2000) Blood 95: 2600-2609.

Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene50848Q9Y624
Antibodies

Revised June 25, 2008


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