最近的技术进步导致发现了由小型开放阅读框(smORF)编码的数百至数千种肽和小蛋白质(微蛋白)。新微蛋白的表征证明了它们在基本生物学过程中的作用,并突出了发现和表征更多微蛋白的价值。阐明微蛋白-蛋白相互作用(MPI)可用于确定微蛋白的生化和细胞作用。在这项研究中,我们使用依赖APEX2的邻近标记策略来表征线粒体延伸因子1微蛋白(MIEF1-MP)的蛋白质相互作用伙伴。MIEF1-MP定位于线粒体基质,在此处与线粒体核糖体(线粒体)相互作用。功能研究表明,MIEF1-MP通过与线粒体结合而调节线粒体翻译。MIEF1-MP的丢失会降低线粒体翻译速率,而MIEF1-MP的升高水平则会提高翻译速率。MIEF1-MP的鉴定揭示了一个与此过程有关的新基因。
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MIEF1 Microprotein Regulates Mitochondrial Translation
Recent technological advances led to the discovery of hundreds to thousands of peptides and small proteins (microproteins) encoded by small open reading frames (smORFs). Characterization of new microproteins demonstrates their role in fundamental biological processes and highlights the value in discovering and characterizing more microproteins. The elucidation of microprotein–protein interactions (MPIs) is useful for determining the biochemical and cellular roles of microproteins. In this study, we characterize the protein interaction partners of mitochondrial elongation factor 1 microprotein (MIEF1-MP) using a proximity labeling strategy that relies on APEX2. MIEF1-MP localizes to the mitochondrial matrix where it interacts with the mitochondrial ribosome (mitoribosome). Functional studies demonstrate that MIEF1-MP regulates mitochondrial translation via its binding to the mitoribosome. Loss of MIEF1-MP decreases the mitochondrial translation rate, while an elevated level of MIEF1-MP increases the translation rate. The identification of MIEF1-MP reveals a new gene involved in this process.