CD3 epsilon

Function

Part of the TCR-CD3 complex present on T-lymphocyte cell surface that plays an essential role in adaptive immune response. When antigen presenting cells (APCs) activate T-cell receptor (TCR), TCR-mediated signals are transmitted across the cell membrane by the CD3 chains CD3D, CD3E, CD3G and CD3Z. All CD3 chains contain immunoreceptor tyrosine-based activation motifs (ITAMs) in their cytoplasmic domain. Upon TCR engagement, these motifs become phosphorylated by Src family protein tyrosine kinases LCK and FYN, resulting in the activation of downstream signaling pathways (PubMed:2470098). In addition of this role of signal transduction in T-cell activation, CD3E plays an essential role in correct T-cell development. Initiates the TCR-CD3 complex assembly by forming the two heterodimers CD3D/CD3E and CD3G/CD3E. Participates also in internalization and cell surface down-regulation of TCR-CD3 complexes via endocytosis sequences present in CD3E cytosolic region (PubMed:10384095, PubMed:26507128).

Involvement in disease

Immunodeficiency 18

IMD18

An autosomal recessive primary immunodeficiency characterized by onset in infancy or early childhood of recurrent infections. The severity is variable, encompassing both a mild immunodeficiency and severe combined immunodeficiency (SCID), resulting in early death without bone marrow transplantation in some patients. Immunologic work-up of the IMD18 SCID patients shows a T cell-negative, B cell-positive, natural killer (NK) cell-positive phenotype, whereas T-cell development is not impaired in the mild form of IMD18.

None

The disease is caused by variants affecting the gene represented in this entry.

Post-translational modifications

Phosphorylated on Tyr residues after T-cell receptor triggering by LCK in association with CD4/CD8.

Cellular localization

• Cell membrane
• Single-pass type I membrane protein

Alternative names

• T-cell surface glycoprotein CD3 epsilon chain
• T-cell surface antigen T3/Leu-4 epsilon chain
• T3E
• CD3E

Database links

• entrezGene:926
• entrezGene:925
• entrezGene:920
• entrezGene:919
• entrezGene:917
• entrezGene:916
• entrezGene:915
• omim:186730
• omim:186740
• omim:186780
• omim:186940
• omim:186910
• omim:186830
• omim:186790
• swissprot:P07766
• swissprot:P10966
• swissprot:P20963
• swissprot:P01732
• swissprot:P01730
• swissprot:P04234
• swissprot:P09693

Target type

Proteins

Primary research area

Immuno-oncology

Other research areas

• Immunology & Infectious Disease

Molecular weight

23147Da