Pre-TCRalpha and TCRalpha are not interchangeable partners of TCRbeta during T lymphocyte development.
In contrast with the alphabeta T cell receptor (TCR), the pre-TCR spontaneously segregates to membrane rafts from where it signals in a cell-autonomous fashion. The disparate behaviors of these two receptors may stem either from differences inherent to the distinct developmental stages during which they are expressed, or from features intrinsic and unique to the receptor components themselves. Here, we express TCRalpha precisely at the pre-TCR checkpoint, at levels resembling those of endogenous pre-TCRalpha (pTalpha), and in the absence of endogenous pTalpha. Both in isolation and more dramatically when in competition with pTalpha, TCRalpha induced defective proliferation, survival, and differentiation of alphabeta T lymphocyte precursors, as well as impaired commitment to the alphabeta T lymphocyte lineage. Substitution of TCRalpha transmembrane and cytoplasmic domains with those of pTalpha generated a hybrid molecule possessing enhanced competitive abilities. We conclude that features intrinsic to the pre-TCR, which are absent in TCRalpha, are essential for its unique function.
Department of Pathology, Harvard Medical School, Dana-Farber Cancer Institute, Smith Building, 1 Jimmy Fund Way, Boston, MA 02115, USA.
Christine
C
Borowski
Xiaoyan
X
Li
Iannis
I
Aifantis
Fotini
F
Gounari
Harald
H
von Boehmer
D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation; D017931:DNA Primers / Q000235:genetics; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology*
D017931:DNA Primers; D008562:Membrane Glycoproteins; D016693:Receptors, Antigen, T-Cell, alpha-beta; C090377:pre-T cell receptor alpha