Fig. 3: USP15 increases the protein stability of FABP1/4 and Perilipin1/2 and lipid accumulation in hepatocytes.

a Western blot analysis showing the dose dependency of HA-FABP4 or HA-PLIN1 in HEK293 cells with increasing FLAG-USP15. b Effects of USP15 knockdown on the protein stability of FABP1/4 and Perilipin1/2. AML12 cells were transfected with siRNA against USP15, and cells were treated with or without 20 μM MG132 for 8 h. c Western blots of AML12 cells treated with cycloheximide as indicated. d Normalized protein levels of FABP1/4 and Perilipin1/2 from (c). e Representative image of Oil Red O staining of AML12 cells treated with oleic acid as indicated with or without siRNA against USP15. f Normalization of Oil Red O staining from (e). Data were represented as the mean ± SEM. *p < 0.05, **p < 0.01, and ***p < 0.001 compared to scRNA. g Western blots of AML12 cells transfected with either USP15 WT or C298A followed by oleic acid treatments as indicated. Data were represented as the mean ± SEM. *p < 0.05 and **p < 0.01 compared to USP15 WT. h Representative image of Oil Red O staining of AML12 cells transfected with either USP15 WT or C298A mutant. Cells were treated with oleic acid as indicated. i Normalization of Oil Red O staining from (h). Data were represented as the mean ± SEM. *p < 0.05 and **p < 0.01 compared to empty vector.