bims-cytox1 Biomed News
on Cytochrome oxidase subunit 1
Issue of 2022‒05‒22
three papers selected by
Gavin McStay
Staffordshire University

  1. Biochem Soc Trans. 2022 May 19. pii: BST20220195. [Epub ahead of print]
      Mitochondrial function relies on the homeostasis and quality control of their proteome, including components of the oxidative phosphorylation (OXPHOS) pathway that generates energy in form of ATP. OXPHOS subunits are under constant exposure to reactive oxygen species due to their oxidation-reduction activities, which consequently make them prone to oxidative damage, misfolding, and aggregation. As a result, quality control mechanisms through turnover and degradation are required for maintaining mitochondrial activity. Degradation of OXPHOS subunits can be achieved through proteomic turnover or modular degradation. In this review, we present multiple protein degradation pathways in plant mitochondria. Specifically, we focus on the intricate turnover of OXPHOS subunits, prior to protein import via cytosolic proteasomal degradation and post import and assembly via intra-mitochondrial proteolysis involving multiple AAA+ proteases. Together, these proteolytic pathways maintain the activity and homeostasis of OXPHOS components.
    Keywords:  degradation; mitochondria; oxidative phosphorylation; protease; proteolysis; respiratory system
  2. New Phytol. 2022 May 19.
      One of the key functions of mitochondria is the production of ATP to support cellular metabolism and growth. The last step of mitochondrial ATP synthesis is performed by the oxidative phosphorylation (OXPHOS) system, an ensemble of protein complexes embedded in the inner mitochondrial membrane. In the last 25 years, many structures of OXPHOS complexes and supercomplexes have been resolved in yeast, mammals and bacteria. However, structures of plant OXPHOS enzymes only became available very recently. In this review, we highlight the plant-specific features revealed by the recent structures and discuss how they advance our understanding of the function and assembly of plant OXPHOS complexes. We also propose new hypotheses to be tested and discuss older findings to be re-evaluated. Further biochemical and structural work on the plant OXPHOS system will lead to a deeper understanding of plant respiration and its regulation, with significant agricultural, environmental and societal implications.
    Keywords:  high-resolution structures; oxidative phosphorylation system; plant mitochondria; protein complexes; respiration; structure-function; supercomplexes
  3. Science. 2022 May 20. 376(6595): 794-795
      Variation in complex composition provides clues about the function of individual subunits.