title: Contributions of the T cell receptor-associated CD3gamma-ITAM to thymocyte selection.
abstract: The immunoreceptor tyrosine-based activation motifs (ITAMs) in the CD3 chains associated with the T cell receptor (TCR) are crucial for TCR signaling. To probe the role of the CD3gamma-ITAM in T cell development, we created knock-in mice in which the CD3gamma chain of the TCR complex is replaced by a mutant signaling-deficient CD3gamma chain, lacking the CD3gamma-ITAM. This mutation results in considerable impairment in positive selection in the polyclonal TCR repertoire. When CD3gamma-deltaITAM mice are crossed to mice expressing transgenic F5 TCRs, their thymocytes are completely unable to perform positive selection in vivo in response to intrathymic ligands. Also, the in vitro positive selection response of double-positive (DP) thymocytes with F5-CD3gamma-deltaITAM mutant receptors to their agonist ligand and many of its variants is severely impaired or abrogated. Yet, the binding and dissociation constants of agonist ligands for the F5 receptor are not affected by the CD3gamma-deltaITAM mutation. Furthermore, DP thymocytes with mutant receptors can respond to agonist ligand with normal antigen sensitivity and to normal levels, as shown by their ability to induce CD69 up-regulation, TCR down-regulation, negative selection, and ZAP70 and c-Jun NH2-terminal kinase activation. In sharp contrast, induction of extracellular signal-regulated kinase (ERK) activation and linker for activation of T cells (LAT) phosphorylation are severely impaired in these cells. Together, these findings underscore that intrinsic properties of the TCR-CD3 complex regulate selection at the DP checkpoint. More importantly, this analysis provides the first direct genetic evidence for a role of the CD3gamma-ITAM in TCR-driven thymocyte selection.
authors.affiliation: Division of Immunology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands.
authors.forename: Mariëlle C
authors.initials: MC
authors.lastname: Haks
authors.forename: Elsa
authors.initials: E
authors.lastname: Pépin
authors.forename: Jeroen H N
authors.initials: JH
authors.lastname: van den Brakel
authors.forename: Sigrid A A
authors.initials: SA
authors.lastname: Smeele
authors.forename: Stanley M
authors.initials: SM
authors.lastname: Belkowski
authors.forename: Helmut W H G
authors.initials: HW
authors.lastname: Kessels
authors.forename: Paul
authors.initials: P
authors.lastname: Krimpenfort
authors.forename: Ada M
authors.initials: AM
authors.lastname: Kruisbeek
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs / Q000502:physiology; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D017252:CD3 Complex / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015704:CD4 Antigens / Q000096:biosynthesis; D016827:CD8 Antigens / Q000096:biosynthesis; D002352:Carrier Proteins / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology*; D002478:Cells, Cultured; D003433:Crosses, Genetic; D004789:Enzyme Activation / Q000187:drug effects; D005434:Flow Cytometry; D066298:In Vitro Techniques; D048031:JNK Mitogen-Activated Protein Kinases; D037181:Lectins, C-Type; D008024:Ligands; D008565:Membrane Proteins; D051379:Mice; D008817:Mice, Mutant Strains; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D051746:ZAP-70 Protein-Tyrosine Kinase; D000099192:CD69 Antigens
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D002352:Carrier Proteins; D048031:JNK Mitogen-Activated Protein Kinases; D037181:Lectins, C-Type; D008024:Ligands; D008565:Membrane Proteins; D020928:Mitogen-Activated Protein Kinases; D010750:Phosphoproteins; D011505:Protein-Tyrosine Kinases; D011948:Receptors, Antigen, T-Cell; D051746:ZAP-70 Protein-Tyrosine Kinase; D000099192:CD69 Antigens; C452842:CD3 antigen, gamma chain; C491734:Lat protein, mouse; C497262:Zap70 protein, mouse