Vascular endothelial junction-associated molecule, a novel member of the immunoglobulin superfamily, is localized to intercellular boundaries of endothelial cells
D. Palmeri et al., Vascular endothelial junction-associated molecule, a novel member of the immunoglobulin superfamily, is localized to intercellular boundaries of endothelial cells, J BIOL CHEM, 275(25), 2000, pp. 19139-19145
During the process of lymphocyte homing to secondary lymphoid organs, such
as lymph nodes and tonsils, lymphocytes interact with and cross a specializ
ed microvasculature, known as high endothelial venules, There is a great de
al of information available about the first steps in the homing cascade, bu
t molecular understanding of lymphocyte transmigration through the intercel
lular junctions of high endothelial venules is lacking. In analyzing expres
sed sequence tags from a cDNA library prepared from human tonsillar high en
dothelial cells, we have identified a cDNA encoding a novel member of the i
mmunoglobulin superfamily, The protein, which we have termed VE-JAM ("vascu
lar endothelial junction-associated molecule"), contains two extracellular
immunoglobulin-like domains, a transmembrane domain, and a relatively short
cytoplasmic tail. VE-JAM is prominently expressed on high endothelial venu
les but is also present on the endothelia of other vessels. Strikingly, it
is highly localized to the intercellular boundaries of high endothelial cel
ls. VE-JAM is most homologous to a recently identified molecule known as Ju
nctional Adhesion Molecule, which is concentrated at the intercellular boun
daries of both epithelial and endothelial cells. Because the Junctional Adh
esion Molecule has been strongly implicated in the processes of neutrophil
and monocyte transendothelial migration, an analogous function of VE-JAM du
ring lymphocyte homing is plausible.