The TCR complex consists of a ligand specific alpha/beta heterodimer non-covalently associated with five invariant chains including the CD3 gamma, delta, eta and zeta subunits. This complex regulates assembly and expression of the receptor and is thought to be responsible for transmembrane transduction of signals after binding to TCRαβ. Studies have suggested that the CD3z subunit (also know as CD247) plays an important role in two distinct cellular compartments. In the cytoplasm, it may function to regulate Ag receptor expression and in the plasma membrane it may be required for optimal signaling by the physiologic ligand Ag/MHC. The CD3z subunit is also associated with the CD16 IgG Fc receptor on NK cells.Synonyms: CD3 zeta chain, T-cell receptor T3 zeta chain, T-cell surface glycoprotein CD3 zeta chain, T3Z, TCRZ