IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
PLoS One. 2012;7(3):e34270. doi: 10.1371/journal.pone.0034270. Epub 2012 Mar 28.
The genome from Neurospora crassa presented three open reading frames homologous to the genes coding for human AIF and AMID proteins, which are flavoproteins with oxidoreductase activities implicated in caspase-independent apoptosis. To investigate the role of these proteins, namely within the mitochondrial respiratory chain, we studied their cellular localization and characterized the respective null mutant strains. Efficiency of the respiratory chain was analyzed by oxygen consumption studies and supramolecular organization of the OXPHOS system was assessed through BN-PAGE analysis in the respective null mutant strains. The results demonstrate that, unlike in mammalian systems, disruption of AIF in Neurospora does not affect either complex I assembly or function. Furthermore, the mitochondrial respiratory chain complexes of the mutant strains display a similar supramolecular organization to that observed in the wild type strain. Further characterization revealed that N. crassa AIF appears localized to both the mitochondria and the cytoplasm, whereas AMID was found exclusively in the cytoplasm. AMID2 was detected in both mitochondria and cytoplasm of the amid mutant strain, but was barely discernible in wild type extracts, suggesting overlapping functions for the two proteins.
粗糙脉孢菌的基因组呈现出三个开放阅读框，与编码人类 AIF 和 AMID 蛋白的基因同源，这些蛋白是具有氧化还原酶活性的黄素蛋白，与细胞凋亡过程中 caspase 无关。为了研究这些蛋白的作用，特别是在线粒体呼吸链中的作用，我们研究了它们的细胞定位，并对相应的缺失突变株进行了特征描述。通过耗氧量研究分析呼吸链的效率，通过 BN-PAGE 分析评估 OXPHOS 系统的超分子组织，在相应的缺失突变株中进行。结果表明，与哺乳动物系统不同，粗糙脉孢菌中 AIF 的缺失并不影响复合物 I 的组装或功能。此外，突变株的线粒体呼吸链复合物显示出与野生型菌株观察到的相似的超分子组织。进一步的特征描述表明，粗糙脉孢菌的 AIF 似乎定位于线粒体和细胞质，而 AMID 仅存在于细胞质中。在 amid 突变株中，AMID2 被检测到在线粒体和细胞质中，但在野生型提取物中几乎不可见，这表明这两种蛋白具有重叠的功能。
