THE INTERCHAIN DISULFIDE BOND BETWEEN TCR-ALPHA-BETA HETERODIMERS ON HUMAN T-CELLS IS NOT REQUIRED FOR TCR-CD3 MEMBRANE EXPRESSION AND SIGNAL-TRANSDUCTION

In the present paper, it was attempted to define the amino acids or re gions on TCR beta molecules that determine the TCR alpha-TCR beta inte raction. Sequence studies on HBP-ALL variant cells with an intrinsic d eficiency in TCR alpha beta dimer formation elucidated a conserved ami no acid motif in the TCR-C-beta beta-strand E, = Y(C)(L)(S)SRLR(V)(S)( A); this motif seems to represent one interaction area for the TCR alp ha-TCR beta interaction. In addition, amino acids in the connecting pe ptide may be shaped in a precise structure (by the interactions with C D3 molecules?) involved in TCR alpha-TCR beta dimerization. This resul t was supported by the finding that the interchain disulfide bond betw een TCR alpha and beta chains is not required for membrane expression or transmembrane signal transduction of TCR alpha beta-CD3 complexes. Finally, comparative results from two membrane TCR-CD3-negative Jurkat variants R4.9 and E6.E12 suggest that TCR-C-beta exon 1- and 5-encode d amino acids are important for the TCR beta-CD3 gamma epsilon associa tion.