Project description:CD5 is characterized as an inhibitory co-receptor with important regulatory role during T cell development. To study the molecular mechanism by which CD5 operates, we used quantitative mass spectrometry to analyze the components of the CD5 signaling machinery in primary T cells. In a first set of experiments, CD5-containing complexes were immunoprecipitated from thymocytes of wild-type (WT) C57BL/6 mice. Thymocytes were treated with pervanadate to induce widespread activation of protein tyrosine kinases. Corresponding samples prepared from thymocytes of Cd5−/− mice were used as controls, to discriminate CD5-binding molecules from the background of contaminant proteins. Eight biological replicates were prepared for both conditions, and samples were analyzed in duplicate LC-MS runs. This first set of experiment is presented in TableS1 of the paper, and is associated to the MaxQuant result file “Interactome WT” in the present PX dataset. We analyzed the CD5 interactome at different time of stimulation with pervanadate (1min and 10min) using thymocytes from wild-type (WT) C57BL/6 mice. Corresponding samples prepared from thymocytes of Cd5−/− mice were used as controls. Three biological replicates were prepared for both conditions (WT and KO) and each time point (1min and 10min). This set of experiments is presented in TableS2 of the paper and is associated to the MaxQuant result file “Interactome at 1min and 10min” in the present PX dataset. We checked that the activation of CD5 (phosphorylation sites) and the formation of the signaling complex was comparable in different stimulatory conditions (comparison of WT thymocytes stimulated with either pervanadate or anti-CD3+anti-CD4 antibodies). We also analyzed the binding of CD5 interactors in thymocytes from a c-Cbl-/- mouse model (comparison of WT and c-Cbl-/-thymocytes stimulated with pervanadate). These experiments and the associated experimental design of the comparisons are summarized in TableS3 of the paper, and are based on the MaxQuant result file “Comparison of different stimulatory conditions” in this dataset. To check the phosphorylation status of the CD5 tyrosine residues at different time of stimulation, we analyzed samples immunoprecipitated from thymocytes of wild-type (WT) C57BL/6 mice, following stimulation with anti-CD3+anti-CD4 antibodies for 1min, 3min and 10min. This set of experiment is presented in TableS4 of the paper and is associated to the MaxQuant result file “CD5 pY kinetics” in the present PX dataset. To determine the role of Y429 in the context of CD5 signaling, we expressed a wild-type (CD5tgWt) or a mutated form of CD5, containing a tyrosine to phenylalanine substitution at position 429 (CD5tgY429F) in transgenic mice. We analyzed the CD5 interactome by comparing samples immunoprecipitated from thymocytes of these 2 mice models (following pervanadate stimulation, 6 and 5 biological replicates respectively) with samples prepared in the same way from Cd5−/− mice as controls (6 biological replicates). The results are shown in TableS5 of the paper, and correspond to the MaxQuant result file “interactome CD5tgWt_CD5tgY429F”.

Project description:It has been recently shown that N-ras plays a preferential role in immune cell development and function; specifically: N-ras, but not H-ras or K-ras, could be activated at and signal from the Golgi membrane of immune cells following a low level TCR stimulus. The goal of our studies was to test the hypothesis that N-ras and H-ras played distinct roles in immune cells at the level of the transcriptome. First, we showed via mRNA expression profiling that there were over four hundred genes that were uniquely differentially regulated either by N-ras or H-ras, which provided strong evidence in favor of the hypothesis that N-ras and H-ras have distinct functions in immune cells. We next characterized the genes that were differentially regulated by N-ras in T cells following a low-level TCR stimulus. Of the large pool of candidate genes that were differentially regulated by N-ras downstream of TCR ligation, four genes were verified in qRT-PCR-based validation experiments as being differentially regulated by N-ras (Dntt, Slc9a6, Chst1, and Lars2). Finally, although there was little overlap between individual genes that were regulated by N-ras in unstimulated thymocytes and stimulated CD4+ T-cells, there was a nearly complete correspondence between the signaling pathways that were regulated by N-ras in these two immune cell types. Since we were interested primarily in genes that were differentially regulated by N-ras following a low-level TCR stimulus, our microarray data comparison was between data from TCR-stimulated, WT CD4+ T-cells and from TCR-stimulated, N-ras KO CD4+ T-cells. Genes that were differentially regulated in the comparison between stimulated N-ras KO CD4+ T-cells and unstimulated N-ras KO CD4+ T-cells, as well as those genes that were differentially regulated in the comparison between stimulated WT CD4+ T-cells and unstimulated WT CD4+ T-cells were excluded from this analysis. To determine if N-ras and H-ras regulate different sets of genes in thymocytes, a comparison was made between the set of genes that were differentially regulated by N-ras in the [WT] vs. [N-ras KO] comparison and the set of genes that were differentially regulated by H-ras in the [WT] vs. [H-ras KO] comparison. RNA was extracted from CD4+ T cell splenocytes isolated from 6-20 week old N-Ras KO and WT mice following growth in T cell growth media either with or without 1 microgram/milliliter ant-CD3 and anti-CD28 antibodies. RNA was extracted from thymocytes isolated directly from 6-20 week old N-Ras KO, H-Ras KO and WT mice.

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Mus musculus

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