MR-1S Interacts with PET100 and PET117 in Module-Based Assembly of Human Cytochrome c Oxidase

Publication date: 14 February 2017
Source:Cell Reports, Volume 18, Issue 7
Author(s): Sara Vidoni, Michael E. Harbour, Sergio Guerrero-Castillo, Alba Signes, Shujing Ding, Ian M. Fearnley, Robert W. Taylor, Valeria Tiranti, Susanne Arnold, Erika Fernandez-Vizarra, Massimo Zeviani
The biogenesis of human cytochrome c oxidase (COX) is an intricate process in which three mitochondrial DNA (mtDNA)-encoded core subunits are assembled in a coordinated way with at least 11 nucleus-encoded subunits. Many chaperones shared between yeast and humans are involved in COX assembly. Here, we have used a MT-CO3 mutant cybrid cell line to define the composition of assembly intermediates and identify new human COX assembly factors. Quantitative mass spectrometry analysis led us to modify the assembly model from a sequential pathway to a module-based process. Each module contains one of the three core subunits, together with different ancillary components, including HIGD1A. By the same analysis, we identified the short isoform of the myofibrillogenesis regulator 1 (MR-1S) as a new COX assembly factor, which works with the highly conserved PET100 and PET117 chaperones to assist COX biogenesis in higher eukaryotes.

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By quantitatively analyzing the COX intermediates accumulated in a MT-CO3 mutant, Vidoni et al. modify the existing sequential COX assembly model to a module-based pathway and describe MR-1S as a vertebrate-specific factor involved in COX maturation, cooperating with the highly conserved PET100 and PET117 chaperones.


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