CD3G

The protein encoded by this gene is the CD3-gamma polypeptide, which together with CD3-epsilon, -delta and -zeta, and the T-cell receptor alpha/beta and gamma/delta heterodimers, forms the T-cell receptor-CD3 complex. This complex plays an important role in coupling antigen recognition to several intracellular signal-transduction pathways. The genes encoding the epsilon, gamma and delta polypeptides are located in the same cluster on chromosome 11. Defects in this gene are associated with T cell immunodeficiency. [provided by RefSeq]

CD3g molecule, gamma (CD3-TCR complex)

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 to this role of signal transduction in T-cell activation, CD3G plays an essential role in the dynamic regulation of TCR expression at the cell surface (PubMed:8187769).
Indeed, constitutive TCR cycling is dependent on the di-leucine-based (diL) receptor-sorting motif present in CD3G.

Adaptive immune response Source: UniProtKB-KW
Cell surface receptor signaling pathway Source: UniProtKB
Establishment or maintenance of cell polarity Source: UniProtKB
Fc-gamma receptor signaling pathway involved in phagocytosis Source: Reactome
Membrane organization Source: Reactome
Negative regulation of inflammatory response to antigenic stimulus Source: Reactome
Peptide cross-linking Source: Reactome
Positive thymic T cell selection Source: GO_Central
Protein-containing complex assembly Source: UniProtKB
Protein transport Source: UniProtKB
Regulation of immune response Source: Reactome
Regulation of lymphocyte apoptotic process Source: UniProtKB
T cell activation Source: UniProtKB
T cell receptor signaling pathway Source: Reactome

Cell membrane

Immunodeficiency 17 (IMD17): An autosomal recessive primary immunodeficiency characterized by highly variable clinical severity. Some patients have onset of severe recurrent infections in early infancy that may be lethal, whereas others may be only mildly affected or essentially asymptomatic into young adulthood. More severely affected patients may have evidence of autoimmune disease or enteropathy. The immunologic pattern is similar among patients, showing partial T-cell lymphopenia, decreased amounts of the CD3 complex, and impaired proliferative responses to T-cell receptor dependent stimuli. The phenotype in some patients is reminiscent of severe combined immunodeficiency.

Extracellular: 23-116
Helical: 117-137
Cytoplasmic: 138-182

Phosphorylated on Tyr residues after T-cell receptor triggering by LCK in association with CD4/CD8 (PubMed:2470098). Phosphorylated also by PKC; leading to the TCR complex down-regulation (PubMed:8187769).
Phosphorylated on Tyr residues after T-cell receptor triggering by LCK in association with CD4/CD8.