CD3E

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). In addition to its role as a TCR coreceptor, it serves as a receptor for ITPRIPL1. Ligand recognition inhibits T-cell activation by promoting interaction with NCK1, which prevents CD3E-ZAP70 interaction and blocks the ERK-NFkB signaling cascade and calcium influx (PubMed:38614099).

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

CD3e, T3E, CD3E, T-cell surface glycoprotein CD3 epsilon chain, T-cell surface antigen T3/Leu-4 epsilon chain

Database links

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

Other research areas

• Immunology & Infectious Disease