Fig 2: The expression of PLIN5 was regulated by the JNK-p38-ATF pathway. (A) Protein levels of ATF1, ATF4, p-p38, p38, p-JNK, and JNK were detected by Western Blot. (B) The gray value analysis of A. (C) mRNA levels of ATF1, ATF3, and ATF4 in cells with 200 μM H2O2 treatment were detected by qPCR. (D) The cells were transfected with ATF1 expression vector or pcDNA3.1 vector. The protein levels of ATF1 and PLIN5 were detected through Western Blot. (E) The cells were transfected with ATF4 expression vector or pcDNA3.1 vector. The protein levels of ATF4 and PLIN5 were detected through Western Blot. (F) The effects of ATFs’ expression on PLIN5 transcriptional activity were detected by dual-luciferase reporter assay. (G) Protein levels of p-ASK1, Ask1, p-p38, p38, p-JNK, JNK, and PLIN5 were detected by Western Blot. (H) The gray value analysis of G. GAPDH was used as the reference protein. These experiments were performed in triplicate. * p < 0.05; ** p < 0.01; and n. s., not significant.

Fig 3: Overview of the regulatory mechanism of PSMD1 and PSMD2 that regulates tumor cell proliferation. Briefly, PSMD1 and PSMD2 regulate the phosphorylation of ASK1-p38-JNK and AKT signaling. Then, the expression level of SREBF1 and PPARγ is regulated. Subsequently, these two important transcriptional factors regulate the expression levels of FAs and lipid synthesis-related genes such as FASN, SCD1, ASCL, DGAT and PLIN. The upregulation of these genes induces more lipid droplet (LD) formation, whereas LDs can provide membrane components and energy for cell proliferation. Therefore, PSMD1 and PSMD2 regulate cell proliferation via modulating cellular lipid metabolism

Fig 4: PSMD1 and PSMD2 regulate the expression level of fatty acids (FAs) and lipid synthesis-related genes. a Interference efficiency detection by qRT-PCR. b The expression level of fatty acid synthesis-related genes was detected by qRT-PCR. c The expression level of lipid synthesis-related genes was detected by qRT-PCR. d Overexpression efficiency detection by qRT-PCR. e The expression level of fatty acid synthesis-related genes was detected by qRT-PCR. f The expression level of lipid synthesis-related genes was detected by qRT-PCR. g The ASK1-p38-JNK and AKT signaling in groups of interfered cells and control cells was detected by Western Blot experiments. TUBULIN and GAPDH were the reference proteins. h Grey value analysis of g. ImageJ software was used for this analysis, according to the instructions. i The ASK1-p38-JNK and AKT signaling in the overexpression cell group and control cells was detected by Western Blot experiments. TUBULIN and GAPDH were the reference proteins. j Grey value analysis of i. ImageJ software was used for this analysis, according to the instructions. The statistical significance of differences between means was assessed using an unpaired Student’s t-test (n = 3; *p < 0.05; **p < 0.01) vs. NC