Find CD3 Products Interaction Network for CD3 CD3 Details

Related Pathways T Cell Receptor Signaling Glucocorticoid Receptor Signaling View All Pathways

Synonyms: CD3

TCR Signaling

T-cell receptor signaling leads to T-cell activation and IL-2 production in a complex process that centers on the immunological synapse (IS). Activating receptor clusters and their underlying “signalosomes” form within the IS. The immunological synapse is a bilayer structure that forms at the interface of antigen presenting cells (APC) and antigen-primed T-cells. In the mature synapse, the co-receptors, TCR/CD3 and CD28, aggregate in the central supramolecular activation complex (c-SMAC) and structural molecules, such as the integrin LFA1 and the scaffold protein talin accumulate in the peripheral supramolecular activation complex (p-SMAC).

The T cell receptor-TCR.CD3 (TCR.CD3) complex is a multimeric structure that recognizes and is activated by antigens. The TCR receptor complex is composed of six subunits. Two of these complexes become cross-linked and activated upon antigen binding. Two subunits each, TCRalpha beta or TCRgamma delta, make up the variable region or the TCR receptor complex associated with the cell surface that interacts with the antigen. Consequently there are Ti-TCRalpha beta type and Ti-TCRgamma delta type T-cell receptors. T-cell receptor complexes also contain four CD3 subunits. They can contain two zeta subunits, one epsilon subunit and either a gamma or delta subunit. CD3gamma and CD3delta subunits have similar sequences. Antigen binding leads to the cross-linking and activation of the TCR hexamers. The CD3 subunits mediate cell signaling through the recruitment of a variety of signaling molecules primarily to their phosphorylation activated ten immunoreceptor tyrosine-based activation motifs (ITAMs). The signalosomes contain a variety of adaptor, scaffold and activating molecules including: Fyn; Lck; Zap-70, Vav, PKCtheta, PLCgamma, PI3-K and Grb2. PKCtheta in synergy with calcineurin are essential for IL-2 gene expression via nuclear mobilization of NFkappaB and NFAT.