title: Complementation in trans of altered thymocyte development in mice expressing mutant forms of the adaptor molecule SLP76.
abstract: The adaptor protein SLP76 directs signaling downstream of the T cell receptor (TCR) and is essential for thymocyte development. SLP76 contains three N-terminal tyrosines that are critical for its function. To define the role of these residues in thymocyte development, we generated two lines of "knock-in" mice, one expressing a mutation in tyrosine 145 (Y145F) and a second harboring two point mutations at tyrosines 112 and 128 (Y112-128F). We show here that although thymocyte development requires both Y145- and Y112-128-generated signals, selection was more dependent upon Y145. Although several proximal TCR signaling events were defective in both mutant mice, phosphorylation of the guanine nucleotide exchange factor, Vav1, and activation of Itk-dependent pathways were differentially affected by mutations at Y112-128 and Y145, respectively. Analysis of mice expressing one Y145F and one Y112-128F allele revealed that these mutants could complement one another in trans, demonstrating cooperativity between two or more SLP76 molecules. Thus, the N-terminal tyrosines of SLP76 are required for thymocyte selection but can function on separate molecules to support TCR signaling.
authors.affiliation: Cancer Biology, Abramson Family Cancer Research Institute, 427 BRBII/III, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104, USA.
authors.forename: Martha S
authors.initials: MS
authors.lastname: Jordan
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Smith
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Burns
authors.forename: Jessica-Elise T
authors.initials: JE
authors.lastname: Austin
authors.forename: Kim E
authors.initials: KE
authors.lastname: Nichols
authors.forename: Anna C
authors.initials: AC
authors.lastname: Aschenbrenner
authors.forename: Gary A
authors.initials: GA
authors.lastname: Koretzky
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation / Q000276:immunology*; D005434:Flow Cytometry; D015151:Immunoblotting; D047468:Immunoprecipitation; D051379:Mice; D008817:Mice, Mutant Strains; D009154:Mutation; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D014443:Tyrosine / Q000737:chemistry / Q000235:genetics / Q000276:immunology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D010750:Phosphoproteins; D011948:Receptors, Antigen, T-Cell; C092947:SLP-76 signal Transducing adaptor proteins; D014443:Tyrosine