Knock-in mutation of the distal four tyrosines of linker for activation of T cells blocks murine T cell development.
The integral membrane adapter protein linker for activation of T cells (LAT) performs a critical function in T cell antigen receptor (TCR) signal transduction by coupling the TCR to downstream signaling pathways. After TCR engagement, LAT is tyrosine phosphorylated by ZAP-70 creating docking sites for multiple src homology 2-containing effector proteins. In the Jurkat T cell line, the distal four tyrosines of LAT bind PLCgamma-1, Grb2, and Gads. Mutation of these four tyrosine residues to phenylalanine (4YF) blocked TCR-mediated calcium mobilization, Erk activation, and nuclear factor (NF)-AT activation. In this study, we examined whether these four tyrosine residues were essential for T cell development by generating LAT "knock-in" mutant mice that express the 4YF mutant protein under the control of endogenous LAT regulatory sequences. Significantly, the phenotype of 4YF knock-in mice was identical to LAT(-/)- (null) mice; thymocyte development was arrested at the immature CD4(-)CD8(-) stage and no mature T cells were present. Knock-in mice expressing wild-type LAT protein, generated by a similar strategy, displayed a normal T cell developmental profile. These results demonstrate that the distal four tyrosine residues of LAT are essential for preTCR signaling and T cell development in vivo.
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- Tyrosine
- T-Lymphocytes
- Signal Transduction
- Receptors, Antigen, T-Cell
- Phosphorylation
- Phosphoproteins
- Phenotype
- Mice, Mutant Strains
- Mice, Knockout
- Mice, Inbred C57BL
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Tyrosine
- T-Lymphocytes
- Signal Transduction
- Receptors, Antigen, T-Cell
- Phosphorylation
- Phosphoproteins
- Phenotype
- Mice, Mutant Strains
- Mice, Knockout
- Mice, Inbred C57BL