E. Co-immunofluorescence of p-IRS1 S307 mouse (green) and p-S6 S240/S242 (red) ribosomal protein in IRS1-overexpressing RCS chondrocytes treated with FGF18 (50 ng/mL) for 12h. Nuclei (N) were stained with DAPI (blue). Scale bar 15 μm. Quantification analysis of p-S6 fluorescence intensity in IRS1-overexpressing vs non expressing RCS chondrocytes. Mean +/- standard error of the mean (sem) of N=3 biological replicates. n=35 cells analyzed. Student's paired T-test *p<0.05. 