Reina Simona, Nibali Stefano Conti, Tomasello Marianna Flora, Magrì Andrea, Messina Angela, De Pinto Vito
Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia 64, 95123, Catania, Italy; We.MitoBiotech S.R.L., c.so Italia 172, 95129, Catania, Italy.
Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia 64, 95123, Catania, Italy.
Redox Biol. 2022 May;51:102264. doi: 10.1016/j.redox.2022.102264. Epub 2022 Feb 12.
Unraveling the role of VDAC3 within living cells is challenging and still requires a definitive answer. Unlike VDAC1 and VDAC2, the outer mitochondrial membrane porin 3 exhibits unique biophysical features that suggest unknown cellular functions. Electrophysiological studies on VDAC3 carrying selective cysteine mutations and mass spectrometry data about the redox state of such sulfur containing amino acids are consistent with a putative involvement of isoform 3 in mitochondrial ROS homeostasis. Here, we thoroughly examined this issue and provided for the first time direct evidence of the role of VDAC3 in cellular response to oxidative stress. Depletion of isoform 3 but not isoform 1 significantly exacerbated the cytotoxicity of redox cyclers such as menadione and paraquat, and respiratory complex I inhibitors like rotenone, promoting uncontrolled accumulation of mitochondrial free radicals. High-resolution respirometry of transiently transfected HAP1-ΔVDAC3 cells expressing the wild type or the cysteine-null mutant VDAC3 protein, unequivocally confirmed that VDAC3 cysteines are indispensable for protein ability to counteract ROS-induced oxidative stress.
揭示电压依赖性阴离子通道3（VDAC3）在活细胞中的作用具有挑战性，仍需要一个明确的答案。与VDAC1和VDAC2不同，外膜线粒体孔蛋白3表现出独特的生物物理特性，这表明其具有未知的细胞功能。对携带选择性半胱氨酸突变的VDAC3进行的电生理研究以及关于此类含硫氨基酸氧化还原状态的质谱数据，与异构体3可能参与线粒体活性氧（ROS）稳态一致。在此，我们全面研究了这个问题，并首次提供了VDAC3在细胞对氧化应激反应中作用的直接证据。异构体3而非异构体1的缺失显著加剧了氧化还原循环剂（如甲萘醌和百草枯）以及呼吸复合物I抑制剂（如鱼藤酮）的细胞毒性，促进了线粒体自由基的不受控制积累。对瞬时转染表达野生型或无半胱氨酸突变体VDAC3蛋白的HAP1-ΔVDAC3细胞进行的高分辨率呼吸测定，明确证实VDAC3的半胱氨酸对于蛋白质抵抗ROS诱导的氧化应激的能力是不可或缺的。
