UniProt functional annotation for P09693



	UniProt functional annotation for P09693

UniProt code: P09693.

Organism: Homo sapiens (Human).

Taxonomy: Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.

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 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. {ECO:0000269|PubMed:2470098, ECO:0000269|PubMed:8187769, ECO:0000269|PubMed:8636209}.

Subunit: The TCR-CD3 complex is composed of a CD3D/CD3E and a CD3G/CD3E heterodimers that preferentially associate with TCRalpha and TCRbeta, respectively, to form TCRalpha/CD3E/CD3G and TCRbeta/CD3G/CD3E trimers. In turn, the hexamer interacts with CD3Z homodimer to form the TCR-CD3 complex. Alternatively, TCRalpha and TCRbeta can be replaced by TCRgamma and TCRdelta. {ECO:0000269|PubMed:15136729}.

Subcellular location: Cell membrane {ECO:0000269|PubMed:8636209}; Single-pass type I membrane protein.

Domain: A di-leucine motif and a tyrosine-based motif are individually sufficient to induce both endocytosis and delivery to lysosomes.

Ptm: 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). {ECO:0000269|PubMed:2470098, ECO:0000269|PubMed:8187769}.

Ptm: Phosphorylated on Tyr residues after T-cell receptor triggering by LCK in association with CD4/CD8. {ECO:0000250|UniProtKB:P04234}.

Disease: Immunodeficiency 17 (IMD17) [MIM:615607]: 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. {ECO:0000269|PubMed:1635567, ECO:0000269|PubMed:17277165}. Note=The disease is caused by variants affecting the gene represented in this entry.

Annotations taken from UniProtKB at the EBI.


Organism:		Homo sapiens (Human).
Taxonomy:		Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.



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 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. {ECO:0000269\|PubMed:2470098, ECO:0000269\|PubMed:8187769, ECO:0000269\|PubMed:8636209}.


Subunit:		The TCR-CD3 complex is composed of a CD3D/CD3E and a CD3G/CD3E heterodimers that preferentially associate with TCRalpha and TCRbeta, respectively, to form TCRalpha/CD3E/CD3G and TCRbeta/CD3G/CD3E trimers. In turn, the hexamer interacts with CD3Z homodimer to form the TCR-CD3 complex. Alternatively, TCRalpha and TCRbeta can be replaced by TCRgamma and TCRdelta. {ECO:0000269\|PubMed:15136729}.
Subcellular location:		Cell membrane {ECO:0000269\|PubMed:8636209}; Single-pass type I membrane protein.
Domain:		A di-leucine motif and a tyrosine-based motif are individually sufficient to induce both endocytosis and delivery to lysosomes.
Ptm:		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). {ECO:0000269\|PubMed:2470098, ECO:0000269\|PubMed:8187769}.
Ptm:		Phosphorylated on Tyr residues after T-cell receptor triggering by LCK in association with CD4/CD8. {ECO:0000250\|UniProtKB:P04234}.
Disease:		Immunodeficiency 17 (IMD17) [MIM:615607]: 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. {ECO:0000269\|PubMed:1635567, ECO:0000269\|PubMed:17277165}. Note=The disease is caused by variants affecting the gene represented in this entry.