MON-316 DPYSL4 Regulates Oxygen Consumption Associating with Mitochondrial Supercomplexes

Abstract

Metabolic regulatory function of p53 can play a role in maintaining homeostasis and protecting cells from damage. Here we have identified Dihydropyrimidinase-like 4 (DPYSL4) is a p53-inducible regulator of energy metabolism using RNA sequencingin both cancer cells and normal cells, such as adipocytes. DPYSL4 was localized in the mitochondria in response to DNA damage or hypoxia. Mitochondria was subjected to 2-D BN/SDS-PAGE followed by immunoblotting. DPYSL4 was detected in the same vertical position as complexes I,IIIand IV. To obtain direct evidence of a functional role in energy regulation, we examined the oxygen consumption rate (OCR) using flux analyzer. The knockdown of p53 or DPYSL4 by the CRISPR/Cas9 system showed reduction in OCR in preadipocytes. OCR of HCT116 p53+/+cellswas higher than p53-/-cells and OCR of p53 or DPYSL4 silencing were lower than p53+/+cells with treated by control siRNA. The overexpression of DPYSL4 in H1299 led to elevation of OCR and the overexpression of DPYSL4 deletion mutantdid not lead to elevation of OCR. Overexpression of DPYSL4 in H1299 cells led to a significant reduction matrigel invasion and canceled by DPYSL4 deletion mutant. In line with its loss of function in energy regulation and tumor suppressor function, DPYSL4 deletion mutant abolished its interaction with supercomplexes.Immunohistology of adipose tissues demonstrated that p53 was significantly upregulated in obese patients compared with non-obese patients. This is concomitant with marked infiltration of CD68-positive cells in adipocytes of obese patients. Taken together, these data indicate that DPYSL4 has a tumor suppressor function associated with OXPHOS regulation and may be concerned with pathogenesis of cancer and obesity regulated under p53.