Galkina Kseniia V, Zubareva Valeria M, Kashko Nataliia D, Lapashina Anna S, Markova Olga V, Feniouk Boris A, Knorre Dmitry A
A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.
Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia.
Front Microbiol. 2022 Mar 23;13:816622. doi: 10.3389/fmicb.2022.816622. eCollection 2022.
In mitochondria, a small protein IF suppresses the hydrolytic activity of ATP synthase and presumably prevents excessive ATP hydrolysis under conditions of energy deprivation. In yeast , IF homologs are encoded by two paralogous genes: and . expression is known to aggravate the deleterious effects of mitochondrial DNA (mtDNA) depletion. Surprisingly, no beneficial effects of and were documented for yeast so far, and the functions of and in wild type cells are unclear. Here, we put forward a hypothesis that and bring advantage during the fast start of proliferation after reentry into exponential growth from post-diauxic or stationary phases. We found that yeast cells increase the concentration of both proteins in the post-diauxic phase. Post-diauxic phase yeast cells formed two subpopulations distinct in Inh1p and Stf1p concentrations. Upon exit from the post-diauxic phase cells with high level of Inh1-GFP started growing earlier than cells devoid of Inh1-GFP. However, double deletion of and did not increase the lag period necessary for stationary phase yeast cells to start growing after reinoculation into the fresh medium. These results point to a redundancy of the mechanisms preventing uncontrolled ATP hydrolysis during energy deprivation.
在线粒体中，一种小蛋白IF抑制ATP合酶的水解活性，并可能在能量剥夺条件下防止ATP过度水解。在酵母中，IF同源物由两个旁系同源基因编码： 和 。已知 表达会加重线粒体DNA（mtDNA）耗竭的有害影响。令人惊讶的是，迄今为止，尚未记录到 和 对酵母有任何有益作用，并且它们在野生型细胞中的功能尚不清楚。在这里，我们提出一个假设，即 和 在从生长后期或稳定期重新进入指数生长期后增殖的快速启动过程中带来优势。我们发现酵母细胞在生长后期会增加这两种蛋白质的浓度。生长后期的酵母细胞形成了两个亚群，其Inh1p和Stf1p浓度不同。从生长后期退出时，Inh1-GFP水平高的细胞比没有Inh1-GFP的细胞更早开始生长。然而， 和 的双缺失并没有增加稳定期酵母细胞重新接种到新鲜培养基后开始生长所需的延迟期。这些结果表明，在能量剥夺期间防止ATP不受控制水解的机制存在冗余。
