CD226 PTA1 (outdated term, 'platelet and T cell activation antigen 1') or DNAM-1 (DNAX

DnaX

DnaX is the gene that codes for the τ and γ subunits of the DNA clamp loader of prokaryotes. The eukaryotic equivalent to the DNA clamp loader is Replication Factor C, which is encoded by RFC1, RFC2, RFC3, RFC4, and RFC5....

 Accessory Molecule-1) is a protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that in humans is encoded by the CD226 gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

 which is located on chromosome 18q22.3.

Structure and function

CD226 is a ~65 kDa glycoprotein expressed on the surface of natural killer cell

Natural killer cell

Natural killer cells are a type of cytotoxic lymphocyte that constitute a major component of the innate immune system. NK cells play a major role in the rejection of tumors and cells infected by viruses...

s, platelet

Platelet

Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes.  The average lifespan of a platelet is normally just 5 to 9 days...

s, monocyte

Monocyte

Monocytes are a type of white blood cell and are part of the innate immune system of vertebrates including all mammals , birds, reptiles, and fish. Monocytes play multiple roles in immune function...

s and a subset of T cell

T cell

T cells or T lymphocytes belong to a group of white blood cells known as lymphocytes, and play a central role in cell-mediated immunity. They can be distinguished from other lymphocytes, such as B cells and natural killer cells , by the presence of a T cell receptor on the cell surface. They are...

s. It is a member of the immunoglobulin superfamily

Immunoglobulin superfamily

The immunoglobulin superfamily is a large group of cell surface and soluble proteins that are involved in the recognition, binding, or adhesion processes of cells. Molecules are categorized as members of this superfamily based on shared structural features with immunoglobulins ; they all possess a...

 containing 2 Ig-like domains of the V-set

Immunoglobulin V-set domain

V-set domains are Ig-like domains resembling the antibody variable domain. V-set domains are found in diverse protein families, including immunoglobulin light and heavy chains; in several T-cell receptors such as CD2 , CD4, CD80, and CD86; in myelin membrane adhesion molecules; in junction adhesion...

. CD226 mediates cellular adhesion to other cells bearing its ligands, CD112

PVRL2

Poliovirus receptor-related 2 , also known as PVRL2 and CD112 , is a human gene.-External links:...

 and CD155

CD155

CD155 also known as the poliovirus receptor is a protein that in humans is encoded by the PVR gene.- Function :CD155 is a Type I transmembrane glycoprotein in the immunoglobulin superfamily...

, and cross-linking CD226 with antibodies causes cellular activation.