bims-tricox Biomed News
on Translation, ribosomes and COX
Issue of 2024‒09‒01
three papers selected by
Yash Verma, University of Zurich



  1. Biomolecules. 2024 Aug 09. pii: 975. [Epub ahead of print]14(8):
      Here we review the functions of ribosomal proteins (RPs) in the nucleolar stages of large ribosomal subunit assembly in the yeast Saccharomyces cerevisiae. We summarize the effects of depleting RPs on pre-rRNA processing and turnover, on the assembly of other RPs, and on the entry and exit of assembly factors (AFs). These results are interpreted in light of recent near-atomic-resolution cryo-EM structures of multiple assembly intermediates. Results are discussed with respect to each neighborhood of RPs and rRNA. We identify several key mechanisms related to RP behavior. Neighborhoods of RPs can assemble in one or more than one step. Entry of RPs can be triggered by molecular switches, in which an AF is replaced by an RP binding to the same site. To drive assembly forward, rRNA structure can be stabilized by RPs, including clamping rRNA structures or forming bridges between rRNA domains.
    Keywords:  assembly factors; cryo-electron microscopy; large ribosomal subunit; pre-rRNA processing; protein–rRNA interactions; rRNA folding; ribosomal proteins; ribosome assembly; ribosome assembly intermediates
    DOI:  https://doi.org/10.3390/biom14080975
  2. Biochem Biophys Res Commun. 2024 Aug 08. pii: S0006-291X(24)01038-6. [Epub ahead of print]737 150502
      Ribosome biogenesis is a highly regulated multistep process aided by energy-consuming auxiliary factors. GTPases form the largest class of auxiliary factors used by bacterial, cytosolic, and mitochondrial ribosomes for their maturation. Mtg3, a circularly permuted YqeH family of GTPase, is implicated in the mitoribosome small subunit biogenesis. However, its precise mechanistic role has yet to be characterized. Mtg3 is likely to bind precursor mitoribosome molecules during subunit maturation in vivo. However, this interaction has yet to be observed with mitoribosomes biochemically. In this study, we delineate the specific conditions necessary for preserving the association of Mtg3 with mitoribosomes on a sucrose density gradient. We show that the C-terminal domain of Mtg3 is required for robust binding to the mitoribosome. Furthermore, point mutants likely to abrogate GTP/GDP binding and GTPase activity compromise protein function in vivo. Surprisingly, the association with the mitoribosome was not compromised in mutants likely to be deficient for nucleotide binding/hydrolysis. Thus, our finding supports a model wherein Mtg3 binds to a precursor mitoribosome through its C-terminus to facilitate a conformational change or validate a folding intermediate driven by the GTP/GDP binding and hydrolysis cycle.
    Keywords:  Mitochondria; Mtg3; Ribosome biogenesis; YqeH; cpGTPase
    DOI:  https://doi.org/10.1016/j.bbrc.2024.150502
  3. FEBS Open Bio. 2024 Aug 23.
      Johannes Herrmann is a Professor of Cell Biology at the University of Kaiserslautern in Germany. His research focus is centred on the biogenesis of mitochondrial proteins. Johannes is a member of the German Academy of Sciences and member of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) Biochemistry Panel. He has been a member of the FEBS Publication Committee since 2021. In this interview, he explains the source of his scientific interest in mitochondrial biology and details how the work of the FEBS Publication Committee safeguards the future of the FEBS Press journals.
    DOI:  https://doi.org/10.1002/2211-5463.13879