The CD3 gamma epsilon/delta epsilon signaling module provides normal T cell functions in the absence of the TCR zeta immunoreceptor tyrosine-based activation motifs.
T cell receptor (TCR) signal transduction is mediated by the immunoreceptor tyrosine-based activation motifs (ITAM). The ten ITAM in the TCR complex are distributed in two distinct signaling modules termed TCR zetazeta and CD3 gammaepsilon/deltaepsilon. To delineate the specific role of the zeta ITAM in T cell development and TCR signal transmission, we compared the properties of T cells from different TCR zeta-transgenic lines wherein tyrosine-to-phenylalanine substitutions had been introduced in the zeta subunit. These lines lack selected phosphorylated forms of TCR zeta including just p23, both p21 and p23, or all phospho-zeta derivatives. We report herein that the efficiency of positive selection in HY TCR-transgenic female mice was directly related to the number of zeta ITAM in the TCR. In contrast, TCR-mediated signal transmission and T cell proliferative responses following agonist peptide stimulation were similar and independent of the zeta ITAM. Only the duration of MAPK activation was affected by multiple zeta ITAM substitutions. These results strongly suggest that the ITAM in the CD3 gammaepsilon/deltaepsilon module can provide normal TCR signal transmission, with zeta ITAM providing a secondary function facilitating MAPK activation and positive selection.
Pitcher
Lisa A
LA
Center for Immunology, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
Mathis
Meredith A
MA
Young
Jennifer A
JA
DeFord
Laura M
LM
Purtic
Bozidar
B
Wulfing
Christoph
C
van Oers
Nicolai S C
NS
D020816:Amino Acid Motifs / Q000235:genetics; D000818:Animals; D017252:CD3 Complex / Q000502:physiology*; D002460:Cell Line; D049109:Cell Proliferation; D002478:Cells, Cultured; D008213:Lymphocyte Activation / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D015398:Signal Transduction / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology*; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism*
D017252:CD3 Complex; C452842:CD3 antigen, gamma chain; C472562:CD3delta antigen; C485468:Cd3e protein, mouse; D008565:Membrane Proteins; D011948:Receptors, Antigen, T-Cell; C054979:antigen T cell receptor, zeta chain; D014443:Tyrosine