bims-resufa 2020-02-09 papers

Issue of 2020–02–09
two papers selected by
Vera Strogolova, Marquette University

Front Physiol. 2019 ;10 1555

Rcf1 Modulates Cytochrome c Oxidase Activity Especially Under Energy-Demanding Conditions.

Hannah Dawitz, Jacob Schäfer, Judith M Schaart, Wout Magits, Peter Brzezinski, Martin Ott.

The mitochondrial respiratory chain is assembled into supercomplexes. Previously, two respiratory supercomplex-associated proteins, Rcf1 and Rcf2, were identified in Saccharomyces cerevisiae, which were initially suggested to mediate supercomplex formation. Recent evidence suggests that these factors instead are involved in cytochrome c oxidase biogenesis. We demonstrate here that Rcf1 mediates proper function of cytochrome c oxidase, while binding of Rcf2 results in a decrease of cytochrome c oxidase activity. Chemical crosslink experiments demonstrate that the conserved Hig-domain as well as the fungi specific C-terminus of Rcf1 are involved in molecular interactions with the cytochrome c oxidase subunit Cox3. We propose that Rcf1 modulates cytochrome c oxidase activity by direct binding to the oxidase to trigger changes in subunit Cox1, which harbors the catalytic site. Additionally, Rcf1 interaction with cytochrome c oxidase in the supercomplexes increases under respiratory conditions. These observations indicate that Rcf1 could enable the tuning of the respiratory chain depending on metabolic needs or repair damages at the catalytic site.

Keywords: Rcf1; Rcf2; Saccharomyces cerevisiae; bc1 complex; cytochrome c oxidase; interaction partners; respiratory supercomplex

DOI: https://doi.org/10.3389/fphys.2019.01555

J Intern Med. 2020 Feb 03.

Shaping the mitochondrial inner membrane in health and disease.

Lilia Colina-Tenorio, Patrick Horten, Nikolaus Pfanner, Heike Rampelt.

Mitochondria play central roles in cellular energetics, metabolism and signaling. Efficient respiration, mitochondrial quality control, apoptosis, and inheritance of mitochondrial DNA depend on the proper architecture of the mitochondrial membranes and a dynamic remodeling of inner membrane cristae. Defects in mitochondrial architecture can result in severe human diseases affecting predominantly the nervous system and the heart. Inner membrane morphology is generated and maintained in particular by the mitochondrial contact site and cristae organizing system (MICOS), the F1 Fo -ATP synthase, the fusion protein OPA1/Mgm1, and the non-bilayer-forming phospholipids cardiolipin and phosphatidylethanolamine. These protein complexes and phospholipids are embedded in a network of functional interactions. They communicate with each other and additional factors, enabling them to balance different aspects of cristae biogenesis and to dynamically remodel the inner mitochondrial membrane. Genetic alterations disturbing these membrane shaping factors can lead to human pathologies including fatal encephalopathy, dominant optic atrophy, Leigh syndrome, Parkinson's disease, and Barth syndrome.

Keywords: MICOS; cristae membranes; human disease; mitochondria; mitochondriopathies; oxidative phosphorylation

DOI: https://doi.org/10.1111/joim.13031