The generation of mitochondrial-derived vesicles (MDVs) is implicated in a plethora of vital cell functions, from mitochondrial quality control to peroxisomal biogenesis. The discovery of distinct subtypes of MDVs has revealed the selective inclusion of mitochondrial cargo in response to varying stimuli. However, the true scope and variety of MDVs is currently unclear, and unbiased approaches have yet to be used to understand their biology. Furthermore, as mitochondrial dysfunction has been implicated in many neurodegenerative diseases, it is essential to understand MDV pathways in the nervous system. To address this, we sought to identify the cargo in brain MDVs. We used an in vitro budding assay and proteomic approach to identify proteins selectively enriched in MDVs. 72 proteins were identified as MDV-enriched, of which 31% were OXPHOS proteins. Interestingly, the OXPHOS proteins localized to specific modules of the respiratory complexes, hinting at the inclusion of sub-assemblies in MDVs. Small TIM chaperones were also highly enriched in MDVs, linking mitochondrial chaperone-mediated protein transport to MDV formation. As the two Parkinson’s disease genes PINK1 and Parkin have been previously implicated in MDV biogenesis in response to oxidative stress, we compared the MDV proteomes from the brains of wild-type mice with those of PINK1^-/- and Parkin^-/- mice. No significant difference was found, suggesting that PINK1- and Parkin-dependent MDVs make up a small proportion of all MDVs in the brain. Our findings demonstrate a previously uncovered landscape of MDV complexity and provide a foundation from which further novel MDV functions can be discovered. Data are available via ProteomeXchange with identifier PXD020197.

中文翻译：

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蛋白质组学的线粒体衍生囊泡在脑中揭示了呼吸系统复杂子组件和小TIM伴侣的富集。

从线粒体质量控制到过氧化物酶体生物合成，线粒体来源的囊泡（MDV）的产生与多种重要的细胞功能有关。MDV不同亚型的发现揭示了线粒体货物对不同刺激的选择性包含。但是，目前尚不清楚MDV的真正范围和种类，并且尚无偏倚的方法用于了解其生物学。此外，由于线粒体功能障碍与许多神经退行性疾病有关，因此了解神经系统中的MDV途径至关重要。为了解决这个问题，我们试图识别大脑MDV中的货物。我们使用了体外出芽测定和蛋白质组学方法来鉴定选择性富集MDV的蛋白质。鉴定出72种蛋白质富含MDV，其中31％为OXPHOS蛋白。有趣的是，OXPHOS蛋白定位于呼吸复合物的特定模块，暗示了MDV中包含了子装配体。小型TIM分子伴侣也高度富含MDV，从而将线粒体分子伴侣介导的蛋白质转运与MDV形成联系起来。由于先前已将两个帕金森氏病基因PINK1和Parkin牵涉到MDV生物体中，以响应氧化应激，因此我们将野生型小鼠大脑中的MDV蛋白质组与PINK1 ^-/-和Parkin ^{-/-进行了比较}老鼠。没有发现显着差异，表明PINK1和依赖Parkin的MDV占大脑中所有MDV的一小部分。我们的发现证明了以前未发现的MDV复杂性，并为进一步发现MDV新功能提供了基础。数据可通过ProteomeXchange获得，其标识符为PXD020197。