Principles of mitoribosomal small subunit assembly in eukaryotes

Nature. 2023 Feb;614(7946):175-181. doi: 10.1038/s41586-022-05621-0. Epub 2022 Dec 8.

Abstract

Mitochondrial ribosomes (mitoribosomes) synthesize proteins encoded within the mitochondrial genome that are assembled into oxidative phosphorylation complexes. Thus, mitoribosome biogenesis is essential for ATP production and cellular metabolism1. Here we used cryo-electron microscopy to determine nine structures of native yeast and human mitoribosomal small subunit assembly intermediates, illuminating the mechanistic basis for how GTPases are used to control early steps of decoding centre formation, how initial rRNA folding and processing events are mediated, and how mitoribosomal proteins have active roles during assembly. Furthermore, this series of intermediates from two species with divergent mitoribosomal architecture uncovers both conserved principles and species-specific adaptations that govern the maturation of mitoribosomal small subunits in eukaryotes. By revealing the dynamic interplay between assembly factors, mitoribosomal proteins and rRNA that are required to generate functional subunits, our structural analysis provides a vignette for how molecular complexity and diversity can evolve in large ribonucleoprotein assemblies.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cryoelectron Microscopy*
  • Fungal Proteins / chemistry
  • Fungal Proteins / metabolism
  • Fungal Proteins / ultrastructure
  • GTP Phosphohydrolases
  • Humans
  • Mitochondrial Proteins / chemistry
  • Mitochondrial Proteins / metabolism
  • Mitochondrial Proteins / ultrastructure
  • Mitochondrial Ribosomes* / chemistry
  • Mitochondrial Ribosomes* / metabolism
  • Mitochondrial Ribosomes* / ultrastructure
  • RNA, Ribosomal
  • Ribonucleoproteins* / chemistry
  • Ribonucleoproteins* / metabolism
  • Ribonucleoproteins* / ultrastructure
  • Ribosomal Proteins / chemistry
  • Ribosomal Proteins / metabolism
  • Ribosomal Proteins / ultrastructure
  • Ribosome Subunits, Small* / chemistry
  • Ribosome Subunits, Small* / metabolism
  • Ribosome Subunits, Small* / ultrastructure
  • Saccharomyces cerevisiae* / cytology
  • Saccharomyces cerevisiae* / metabolism

Substances

  • Mitochondrial Proteins
  • Ribosomal Proteins
  • RNA, Ribosomal
  • GTP Phosphohydrolases
  • Ribonucleoproteins
  • Fungal Proteins