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) beta chain is the bulky solvent-exposed FG loop on the C beta 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 alpha/beta chains during TCR signaling. However, functional analysis does not support the above notion, since transgene coding for TCR beta chain lacking the complete FG loop supports normal alpha/beta T cell development and function.