G. Immunofluorescence staining of CLIMP63 (green) and lysosomes (TMEM192-HA, red) in RCS chondrocytes with indicated genotypes (ctrl=wild type) upon FGF18 treatment (50 ng/mL for 16h). BafA1 (100 nM; 4 hours) was used to inhibit lysosomal degradation; scale bar 20 μm. Insets show magnification of CLIMP63 accumulation into lysosomes; scale bar 2 μm. Quantification of CLIMP63 fluorescence intensity into TMEM192-HA decorated lysosomes. Mean +/- standard error of the mean (sem) of N=3 biological replicates. n=10 cells/experiment were analyzed. Analysis of variance one way (ANOVA) p=1.55e-7; Tukey's post hoc test ***p<0.0005; NS not significant. H. EATR assay in RCS with indicated genotypes (ctrl=wild type) showing % of cells with acidified ER by FACS analysis. FGF18 was used at 50 ng/mL for 16 hours. Mean +/- standard error of the mean (sem) of N=4 biological replicates/treatment/genotype. Analysis of variance one way (ANOVA) p<0.0001; Tukey's post hoc test ***p<0.0005; NS not significant. 