Junctional adhesion molecule B is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
that in humans is encoded by the ''JAM2''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
JAM2 has also been designated as CD322 (
cluster of differentiation
The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of cell surface molecules providing targets for immunophen ...
322).
Function
Tight junction
Tight junctions, also known as occluding junctions or ''zonulae occludentes'' (singular, ''zonula occludens''), are multiprotein junctional complexes whose canonical function is to prevent leakage of solutes and water and seals between the epith ...
s represent one mode of cell-to-cell adhesion in
endothelial cell
The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel ...
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
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
superfamily gene member is localized in the tight junctions between
high endothelial cells. It acts as an adhesive ligand for interacting with a variety of
immune cell
White blood cells, also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from mult ...
types and may play a role in
lymphocyte
A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic ad ...
homing to secondary
lymphoid organs
The lymphatic system, or lymphoid system, is an organ system in vertebrates that is part of the immune system, and complementary to the circulatory system. It consists of a large network of lymphatic vessels, lymph nodes, lymphatic or lymphoid ...
.
It is purported to promote lymphocyte transendothelial migration.
It might also be involved with endothelial cell polarity, by associating to cell polarity protein PAR-3, together with JAM3.
Interactions
JAM2 has been shown to
interact
Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...
with
PARD3
Partitioning defective 3 homolog is a protein that in humans is encoded by the ''PARD3'' gene.
Function
PARD proteins, which were first identified in C. elegans, are essential for asymmetric cell division and polarized growth, whereas CDC42 (M ...
.
It also interacts with the
integrin
Integrins are transmembrane receptors that facilitate cell-cell and cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle, ...
dimer
VLA-4
Integrin α4β1 (very late antigen-4) is an integrin dimer. It is composed of CD49d (alpha 4) and CD29 (beta 1). The alpha 4 subunit is 155 kDa, and the beta 1 subunit is 150 kDa.
Function
The integrin VLA-4 is expressed on the cell surfaces ...
(also called α4β1).
References
Further reading
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
External links
*
*
Clusters of differentiation
{{membrane-protein-stub