PKC Delta positively regulates peroxisome abundance. (A) Schematic of different PKC isoforms used in B. (B) Confocal microscopy of HEK293T CRISPR/Cas9 PMP70-GFP cells overexpressing (OE) PKCα-mCherry, PKCδ-mCherry, or PKCζ-mCherry. See zoomed out images in Fig. S1 H. Quantification shows the number of peroxisomes per square micron of the cytoplasm in the 2D confocal image, mean ± SEM, N = 100 cells pooled from three biological repeats, ****P < 0.0001, Kruskal–Wallis test. Scale bar: 5 μm. (C) Confocal microscopy of peroxisomes in human primary fibroblasts AFF11 treated with PMA (0.5 μM) for 1 day. Peroxisomes were visualized using PMP70 antibody, and nuclei were stained with Hoechst (10 μg/ml). Representative images are shown; scale bar: 10 μm. Quantification shows the number of peroxisomes per square micron, mean ± SEM, N = 103 cells pooled from three biological repeats, ****P < 0.0001, Mann–Whitney test. (D) Radioactive peroxisomal FAO measurement using 3H-docosanoic acid in HEK293T WT or PEX19KO in control or Go6983 (5 μM for 48 h) conditions. Quantification shows the number of counts per minute, mean ± SEM, N = 6–12 pooled from three biological repeats, ***P < 0.001, ****P < 0.0001, One-way ANOVA. Source data are available for this figure: SourceData F2. ns, nonsignificant.