Elucidating the functions and interactions of mitochondrial porin in Neurospora

真核细胞含有膜结合的隔室，在这些隔间中发生特殊的功能。线粒体容纳了细胞中的大部分能量产生机制，使用细胞器外产生的底物，并将产物输送回细胞质。线粒体由两层膜结合，小分子通过线粒体孔蛋白穿过外膜，也称为电压依赖性阴离子选择通道(VDAC)。这种蛋白质与线粒体内和线粒体周围的许多蛋白质相互作用；这些相互作用被认为是为了调节基本代谢，以及在高等生物中，启动细胞凋亡或程序性细胞死亡。为了了解孔蛋白的功能，我们使用脉孢子虫作为模式生物；它只有一个孔蛋白基因，不像人类有三个，包括一个基本形式。已经产生了一株缺乏孔蛋白的脉孢菌，该菌株缺乏产生能量的成分(细胞色素)，生长缓慢，对冷敏感。它的线粒体改变了结构和蛋白质组成。拟议的工作包括进一步表征这些变化，并确定需要孔蛋白才能正常发挥作用的复杂因素集。将开发基因系统来表达具有特定序列变化的孔蛋白变体；这些变化对细胞的影响将使确定孔蛋白的不同功能部分成为可能。 另一种正在研究的线粒体蛋白质是复制线粒体染色体的酶。在面包酵母和其他真菌中，这种DNA聚合酶有一个未知功能的额外区域。我们正试图确定结构域的哪些部分是必不可少的，以及它是如何参与DNA复制的。酵母线粒体DNA聚合酶被用作人类线粒体疾病的模型，因此了解其功能在基础生物学和疾病方面具有重要意义。 总而言之，这些研究探讨了线粒体生物学的基本方面。

Eukaryotic cells contain membrane-bound compartments in which specialized functions occur. Mitochondria house much of the energy-generating machinery in the cell, using substrates produced outside of the organelle, and transporting products back into the cytoplasm. Mitochondria are bound by two membranes, and small molecules pass through the outer membrane via mitochondrial porin, also known as the voltage-dependent anion-selective channel (VDAC). This protein interacts with numerous proteins in and surrounding the mitochondria; these interactions are proposed to regulate basic metabolism, and in higher organisms, the initiation of apoptosis, or programmed cell death. To understand the function of porin, we are using Neurospora as a model organism; it contains a single porin gene, unlike humans which have three, including one essential form. A strain of Neurospora lacking porin has been generated, and suffers from deficiencies in energy-generating components (cytochromes), grows slowly and is cold-sensitive. Its mitochondria have altered structures and protein composition. The proposed work involves further characterizing these changes, and determining the complex set of factors that require porin for normal function. Genetic systems will be developed to express porin variants with defined sequence changes; the effects of these changes on the cells will enable determination of the different functional parts of porin. A second mitochondrial protein under study is the enzyme that replicates the mitochondrial chromosome. In bread yeast and other fungi, this DNA polymerase has an extra domain of unknown function. We are attempting to determine which parts of the domain are essential, and how it is involved in DNA replication. Yeast mitochondrial DNA polymerase is used as a model for human mitochondrial disease, and therefore understanding its function is important in terms of basic biology and disease. Together, these studies investigate fundamental aspects of mitochondrial biology.