Fig. 6: Identification of proteins in proximity to Roquin-1 in CD4⁺ T cells.

Expression of BirA*-Roquin-1 and biotin tagging define a subset of the T cell RBPome in close proximity to Roquin-1. a Schematic overview of the BioID method showing how the addition of biotin to the medium leads to the activation of biotin, diffusion of biotinoyl-5’AMP and the biotinylation of the bait (Roquin-1) and all preys in the circumference. b Equimolar amounts of protein were loaded onto a PAGE gel for Western blotting applying an anti-biotin antibody. Efficient biotinylation of both baits BirA*-Roquin-1 and BirA*-GFP (control) could be demonstrated (n = 2). c Histogram showing that transduction of CD4⁺ T cells with retrovirus to inducibly express BirA*-Roquin-1 lead to the efficient downregulation of endogenous Icos. d Identified preys from Roquin-1 BioIDs (n = 5) in CD4⁺ T cells. Depicted are all significantly enriched proteins with the exception of highly abundant ribosomal and histone proteins. A two-sided heteroscedastic Student’s T-test analysis was performed. Dot sizes equal p-values and positioning towards the center implies increased x-fold enrichment over BirA*-GFP BioID results. e Venn diagram showing the overlap of RBPs from the CD4⁺ T cell RBPome with the proteins identified by Roquin-1 BioID in T cells. Source data are provided as a Source Data file.