title: Disruption of T cell signaling networks and development by Grb2 haploid insufficiency.
abstract: The developmental processes of positive and negative selection in the thymus shape the T cell antigen receptor (TCR) repertoire and require the integration of multiple signaling networks. These networks involve the efficient assembly of macromolecular complexes and are mediated by multimodular adaptor proteins that permit the functional integration of distinct signaling molecules. We show here that decreased expression of the adaptor protein Grb2 in Grb2+/- mice weakens TCR-induced c-Jun N-terminal kinase (JNK) and p38, but not extracellular signal-regulated kinase (ERK), activation. In turn, this selective effect decreases the ability of thymocytes to undergo negative, but not positive, selection. We also show that there are differences in the signaling thresholds of the three mitogen-activated protein kinase (MAPK) families. These differences may provide a mechanism by which quantitative differences in signal strength can alter the balance of downstream signaling pathways to induce the qualitatively distinct biological outcomes of proliferation, differentiation or apoptosis.
authors.affiliation: Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Gong
authors.forename: A M
authors.initials: AM
authors.lastname: Cheng
authors.forename: A M
authors.initials: AM
authors.lastname: Akk
authors.forename: J
authors.initials: J
authors.lastname: Alberola-Ila
authors.forename: G
authors.initials: G
authors.lastname: Gong
authors.forename: T
authors.initials: T
authors.lastname: Pawson
authors.forename: A C
authors.initials: AC
authors.lastname: Chan
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D002454:Cell Differentiation; D002455:Cell Division; D004768:Enterotoxins / Q000633:toxicity; D004789:Enzyme Activation; D048031:JNK Mitogen-Activated Protein Kinases; D051379:Mice; D018345:Mice, Knockout; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004768:Enterotoxins; C498726:Mona protein, mouse; D011948:Receptors, Antigen, T-Cell; C031818:enterotoxin B, staphylococcal; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D018631:ras Proteins