Mitoflash generated at the Qo site of mitochondrial Complex III. Issue 4 (15th September 2020)

• Record Type: Journal Article
• Authors: Gao, Meng; Qin, Yuan; Li, Anqi; Wei, Sailei; Liu, Bilin; Tian, Xiangang; Gong, Guohua
• Is Part Of: Journal of cellular physiology. Volume 236:Issue 4(2021)
• Page Start: 2920
• Page End: 2933
• Publication Date: 2020-09-15
• Subjects: deficiency -- mitochondrial function -- mitoflash -- oxidative stress -- Qo site; Physiology -- Periodicals; Cell physiology -- Periodicals; 571.6
• DOI: 10.1002/jcp.30059
• Languages: English
• ISSNs: 0021-9541

Abstract

Abstract: The previous research has shown that mitochondrial flash (mitoflash) genesis are functionally and mechanistically integrated with mitochondrial electron transport chain (ETC) energy metabolism. However, the response of mitoflash to superoxide is not entirely consistent with the response of MitoSOX Red. The generation mechanism of mitoflash is still unclear. Here, we investigated mitoflash activities, using the different combinations of ETC substrates and inhibitors, in permeabilized cardiomyocytes or hearts. We found that blocking the complete electron flow, from Complex I to IV, with any one of ETC inhibitors including rotenone (Rot), antimycin A (AntA), myxothiazol (Myxo), stigmatellin, and sodium cyanide, will lead to the abolishment of mitoflashes triggered by substrates in adult permeabilized cardiomyocytes. However, Myxo boosted mitoflashes triggered by the reverse electron of N, N, N ′, N ′‐tetramethyl‐p‐phenylenediamine/ascorbate. Moreover, Rot and AntA furtherly enhanced mitoflash activity rather than depressed it, suggesting that mitoflashes generated at the Complex III Qo site. Meanwhile, the inhibition of Complex III protein expression resulted in the activity of Complex III decrease, which decreased mitoflash frequency. The function defect (no change of protein level) of the Qo site of Complex III in aging hearts augmented mitoflash generation confirmed the Qo site function was critical to mitoflash genesis. Thus, our results indicate that mitoflash detected by circularly permuted yellow fluorescent protein is generated at the Qo site of Complex III. Abstract : Mitoflash, an individual mitochondrial reactive oxygen species burst event, genesis is integrated with the energy metabolism of the mitochondrial electron transport chain under physiological conditions. Our findings revealed it generated at the Qo site of mitochondrial Complex III.