T Cell Receptor β Chain Lacking the Large Solvent-exposed Cβ FG Loop Supports Normal α/β T Cell Development and Function in Transgenic Mice

The striking and unique structural feature of the T cell receptor (TCR) β chain is the bulky solvent-exposed FG loop on the Cβ domain, the size of almost half an immunoglobulin domain. The location and size of this loop suggested immediately that it could be a crucial structural link between the invariant CD3 subunits and antigen-recognizing α/β chains during TCR signaling. However, functional analysis does not support the above notion, since transgene coding for TCR β chain lacking the complete FG loop supports normal α/β T cell development and function.