NEMO and IRAK1 display partial colocalization in punctate structures in response to IL-1. (A) Immunofluorescence images of NEMO (red) and IRAK1 (green) in U2OS cells left untreated or stimulated with IL-1 for 15 min. Nuclei were stained with DAPI (blue). The insets in the images show magnified areas (indicated by the boxed regions). Bar, 5 µm. (B) Quantification of the number of foci per cell positive for NEMO (red squares) or IRAK1 (blue diamonds) was performed for a time-course of IL-1 stimulation, and the results are presented as mean values ± SD (error bars; n > 950 cells analyzed).