NSF-BSF: The role of protein phosphorylation in the mitochondrial matrix in determining mitophagic selectivity

线粒体，通常被称为“细胞的发电站”，是几乎在人体和大多数真核生物的每个细胞中发现的细胞器。 由于它们参与高能化合物的产生，许多虚假的副反应会产生有毒的自由基，从而损害细胞器。 为了减轻这些毒性作用，细胞已经进化出各种策略来维持细胞健康。其中一种策略被称为线粒体自噬，它促进整个线粒体的周转。由于这种周转发生在细胞器水平上，因此假设大多数经历线粒体自噬的线粒体蛋白质将具有相似的周转率，因为它们共同容纳在单个细胞器中。然而，最近的数据表明，特定的线粒体蛋白质在线粒体自噬的周转率之间的显着偏差。这就引出了一个自然的问题：这种选择性是如何实现的？该项目将通过研究一种众所周知的细胞修饰，蛋白质磷酸化及其与选择性线粒体蛋白质周转的关系来解决这个问题。这项工作的更广泛影响包括其内在价值，因为所有含有这些细胞器的细胞可能使用类似的机制，并且已知当线粒体自噬受损时会出现几种疾病。其他活动包括扩大在科学中代表性不足的群体的参与，特别是妇女和少数民族在生物化学领域的参与。我们的初步研究表明，破坏参与蛋白质磷酸化的酶的表达实质上改变了选定的线粒体蛋白质的周转率。该项目旨在提供一个机械的理解，这是如何发生的，并确定从酵母到哺乳动物系统的这种反应的潜在调节剂。我们将使用同位素标记和质谱法来跟踪线粒体蛋白的周转率，以绘制线粒体吞噬选择性，并确定它是如何被失调的磷酸化改变的。与此同时，我们将测试更集中的假设，以确定蛋白质参与线粒体选择性和分子机制，这一过程发生在酵母，培养细胞和小鼠。了解这些机制将增强我们解决线粒体功能生理失衡的能力，这广泛导致发病和疾病。这个美国/以色列合作项目得到了美国国家科学基金会和以色列两国科学基金会的支持。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Mitochondria, commonly known as ‘the powerhouses of the cell,’ are organelles found in virtually every cell in the human body and in most eukaryotes. Because of their involvement in the production of high energy compounds, many spurious side reactions can produce toxic radicals that can damage the organelle. To mitigate these toxic effects, cells have evolved various strategies to maintain cellular health. One such strategy is termed mitophagy, which promotes the turnover of whole mitochondria. As this turnover occurs at the organellar level, it has been assumed that most mitochondrial proteins undergoing mitophagy would have similar turnover rates, as they are collectively housed within a single organelle. However, recent data demonstrate significant deviation between turnover rates of specific mitochondrial proteins during mitophagy. This leads to a natural question: how is such selectivity achieved? This project will address this question by studying a well-known cellular modification, protein phosphorylation, and its ties to selective mitochondrial protein turnover. The Broader Impacts of the work include its intrinsic merit because all cells harboring these organelles likely use similar mechanisms and several diseases are known to arise when mitophagy is impaired. Additional activities include the broadening participation of underrepresented groups in science, particularly women and minorities in the field of biochemistry.Our preliminary studies suggest that disrupting the expression of enzymes involved in protein phosphorylation substantially alters the turnover rates of select mitochondrial proteins. This project seeks to provide a mechanistic understanding of how this occurs and to identify potential regulators of this response from yeast to mammalian systems. We will use isotopic labeling and mass spectrometry to track the turnover rates of mitochondrial proteins to map the mitophagic selectivity and determine how it is altered by dysregulated phosphorylation. In parallel, we will test more focused hypotheses to determine the proteins involved in mitophagic selectivity and the molecular mechanisms by which this process occurs in yeast, cultured cells, and mice. Understanding these mechanisms will bolster our ability to address physiological imbalances in mitochondrial function, which broadly lead to morbidity and disease. This collaborative US/Israel project is supported by the US National Science Foundation and the Israeli Binational Science FoundationThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.