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T-Cell Receptor
Definition 1
Heterodimeric antigen receptors present on the surface of T-cells. Two T-cell antigen receptors have been identified, consisting of heterodimeric 40-55 kD Ig-like alpha/beta or gamma/delta integral membrane glycoproteins. Genes for TCR alpha, beta, gamma, and delta subunits are assembled during T-cell development by somatic rearrangement of germline gene segments, resembling B-cell Ig genes in their mechanisms of diversity generation and activation of expression. Alpha/beta heterodimers are found on helper and cytotoxic T-cells and are specific for antigenic peptides presented by MHC gene products. T-cells expressing gamma/delta heterodimers directly recognize proteins and non-proteinacious phospho-ligands. T-cell receptors are non-covalently associated with CD3, forming the TCR-CD3 complex. TCRs activate MAPKs and JNK1 through the CD3 antigens, the adaptor protein LAT, and tyrosine kinases LCK and ZAP70. (from OMIM and NCI) (NCI Thesaurus)
Definition 2
Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens (ANTIGENS, CD3). Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta (RECEPTORS, ANTIGEN, T-CELL, ALPHA-BETA) or gamma-delta (RECEPTORS, ANTIGEN, T-CELL, GAMMA-DELTA) chains. (NLM, Medical Subject Headings)
Definition 3
immunoglobulin like receptor associated with CD3 marker on T lymphocytes which binds specific antigen and thereby participates in T cell activation. (NIH CRISP Thesaurus)
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