Early steps in the biogenesis of mitochondrially encoded oxidative phosphorylation subunits

Abstract

The complexes mediating oxidative phosphorylation (OXPHOS) in the inner mitochondrial membrane consist of proteins encoded in the nuclear or the mitochondrial DNA. The mitochondrially encoded membrane proteins (mito‐MPs) represent the catalytic core of these complexes and follow complicated pathways for biogenesis. Owing to their overall hydrophobicity, mito‐MPs are co‐translationally inserted into the inner membrane by the Oxa1 insertase. After insertion, OXPHOS biogenesis factors mediate the assembly of mito‐MPs into complexes and participate in the regulation of mitochondrial translation, while protein quality control factors recognize and degrade faulty or excess proteins. This review summarizes the current understanding of these early steps occurring during the assembly of mito‐MPs by concentrating on results obtained in the model organism baker's yeast.

Multiple structural flavors of RNase P in precursor tRNA processing

“…The tRNA-derived small RNAs (tsRNAs), a class of small ncRNAs that occur due to processing activities of RNase P and similar processing enzymes, could serve as diagnostic markers to track disease progression (Mao et al, 2023). The disease-associated pathogenic variants of the three human mt-RNase P subunits lead to mitochondrial dysfunction in affected individuals displaying variable pleiotropic clinical phenotypes and is characterized by aberrant tRNA processing, insulin resistance, and oxidative phosphorylation (OXPHOS) defects (Chatfield et al, 2015;Hochberg et al, 2021;Hodgkinson et al, 2014;Jung et al, 2023;Metodiev et al, 2016;Rossetti et al, 2021;Sridhara, 2017). The assessment of processing defects by such variants could serve as a valuable assay in determining the clinical manifestation of diseases such as Perrault syndrome (Smith et al, 2023).…”