Structural characterization of the TCR complex by electron microscopy.Structural characterization of the TCR complex by electron microscopy.Arechaga I, Swamy M, Abia D, Schamel WW, Alarcón B, Valpuesta JM* Int. Immunol. 2010, 22(11), 897-903. DOI:10.1093/intimm/dxq443.2010-06-08T22:00:00Z<p style="text-align:justify;"><strong class="ms-rteThemeFontFace-1 ms-rteFontSize-2">​Abstract</strong></p><p style="text-align:justify;"><span class="ms-rteThemeFontFace-1 ms-rteFontSize-2" style="color:#333333;background-color:#ffffff;">Structural information on how the TCR transmits signals upon binding of its antigen peptide MHC molecule ligand is still lacking. The ectodomains of the TCRα/β, CD3εγ and CD3εδ dimers, as well as the transmembrane domain of CD3ζ, have been characterized by X-ray crystallography and nuclear magnetic resonance (NMR). However, no structural data have been obtained for the entire TCR complex. In this study, we have purified the TCR from T cells under native conditions and used electron microscopy to derive a three-dimensional structure. The TCR complex appears as a pear-shaped structure of 180 × 120 × 65 . Furthermore, the use of mAbs has allowed to determine the orientation of the TCRα/β and CD3 subunits and to suggest a model of interactions. Interestingly, the reconstructed TCR is larger than expected for a complex with a αβγεδεζζ stoichiometry. The accommodation of a second TCRαβ to fill in the extra volume is discussed.</span><br></p><p><a href="">​[pubmed]</a><br></p>31