Department of Biochemistry and Molecular Biology, University of Oviedo, 33006-Oviedo, Spain.
Mitochondrion. 2012 May;12(3):370-80. doi: 10.1016/j.mito.2012.02.001. Epub 2012 Feb 12.
Mig2 has been described as a transcriptional factor that in the absence of Mig1 protein is required for glucose repression of the SUC2 gene. Thus, until now, the main role assigned to Mig2 has been the functional redundancy to Mig1. In this study, we report that Mig2 has a double subcellular localization. As expected, in high-glucose conditions it is accumulated in the nucleus but in low-glucose conditions Mig2 has an unexpected mitochondrial localization and role in mitochondrial morphology. We describe that Mig2 physically interacts with the mitochondrial protein Ups1 in a glucose-dependent manner. We also show that Δmig2 mutant cells exhibit a fragmented network of mitochondrial tubules, a phenotype similarly observed in cells lacking Fzo1 and Ups1. Furthermore, Mig2 acts antagonistically with respect to the fission-promoting components, because mitochondrial aggregation induced by DNM1 deletion was rescued in the Δdnm1Δmig2 double mutant. Thus, our studies have revealed an additional role for Mig2 as a novel factor required for the maintenance of fusion-competent mitochondria in Saccharomyces cerevisiae and strongly suggest that Mig2 could be involved in the cross talk between the nucleus and the mitochondria through Ups1 to regulate mitochondrial morphology in a glucose dependent manner.
Mig2 被描述为一种转录因子，在没有 Mig1 蛋白的情况下，它是 SUC2 基因葡萄糖抑制所必需的。因此，到目前为止，Mig2 的主要作用一直是与 Mig1 的功能冗余。在这项研究中，我们报告 Mig2 具有双重亚细胞定位。正如预期的那样，在高葡萄糖条件下，它积累在核内，但在低葡萄糖条件下，Mig2 具有意想不到的线粒体定位和对线粒体形态的作用。我们描述了 Mig2 以葡萄糖依赖的方式与线粒体蛋白 Ups1 发生物理相互作用。我们还表明，Δmig2 突变细胞表现出线粒体小管网络的片段化，这一表型在缺乏 Fzo1 和 Ups1 的细胞中也观察到。此外，Mig2 与促进分裂的成分表现出拮抗作用，因为 DNM1 缺失诱导的线粒体聚集在 Δdnm1Δmig2 双突变体中得到挽救。因此，我们的研究揭示了 Mig2 作为维持酿酒酵母融合能力线粒体的一个新的必需因子的额外作用，并强烈表明 Mig2 可能通过 Ups1 参与核与线粒体之间的串扰，以葡萄糖依赖的方式调节线粒体形态。
