CD3D

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, CD3D plays an essential role in thymocyte differentiation. Indeed, participates in correct intracellular TCR-CD3 complex assembly and surface expression. In absence of a functional TCR-CD3 complex, thymocytes are unable to differentiate properly. Interacts with CD4 and CD8 and thus serves to establish a functional link between the TCR and coreceptors CD4 and CD8, which is needed for activation and positive selection of CD4 or CD8 T-cells (PubMed:12215456).

Involvement in disease

Immunodeficiency 19

IMD19

An autosomal recessive form of severe combined immunodeficiency characterized by onset in early infancy of recurrent bacterial, viral, and fungal infections. Patients usually have chronic diarrhea, recurrent respiratory infections, and failure to thrive. Immunologic work-up shows a T-cell negative, B-cell positive, NK-cell positive phenotype.

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.

Tissue Specificity

CD3D is mostly present on T-lymphocytes with its TCR-CD3 partners. Present also in fetal NK-cells.

Cellular localization

• Cell membrane
• Single-pass type I membrane protein

Alternative names

CD3d, T3D, CD3D, T-cell surface glycoprotein CD3 delta chain, T-cell receptor T3 delta chain

Database links

swissprot:P04234 swissprot:P13591 omim:116930 omim:186740 omim:186780 omim:186790 omim:186830 swissprot:P09693 swissprot:P07766 swissprot:P20963 swissprot:P11836 entrezGene:915 entrezGene:916 entrezGene:917 entrezGene:919 entrezGene:931 entrezGene:4684

Other research areas

• Immunology & Infectious Disease