{
  "id": 6260408,
  "title": "A nucleolar assembly module integrates an ancestral isoaspartylase to safeguard ribosome biogenesis",
  "url": "https://urgent.news/2026/09/08/a-nucleolar-assembly-module-integrates-an-ancestral-isoaspartylase-to",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-08T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.04.749427v1?rss=1"
  },
  "original_language": "en",
  "account": "Eukaryotes acquired the essential ribosome biogenesis machinery from archaea. However, the addition of 200 assembly factors and the requirement for nucleocytoplasmic compartmentalization posed a challenge in integrating this ancestral system into a sophisticated maturation process. A potential solution involves the formation of temporary modules, where newly acquired assembly factors assist deeply conserved components.\n\nIn this investigation, researchers identified such a module, centered around the ancient isoaspartylase Fap7. This module links the modification of the ribosomal protein uS11 to its integration into pre-ribosomes. Fap7 collaborates with Krr1 to capture uS11, creating an initial checkpoint where uS11 loading allows for Kri1 engagement and assembly advancement. If uS11 modification is absent, a later checkpoint intervenes, preventing the creation of defective pre-ribosomes that would otherwise gain translational capability.\n\nThrough integrative structure-function analyses, the study reveals how the ancestral isoaspartylase is embedded within a conserved network of eukaryotic assembly factors. This network ensures the precise timing, sequencing, and accuracy of ribosome production.",
  "summary": "Eukaryotes inherited the core ribosome biogenesis apparatus from archaea. However, nucleocytoplasmic compartmentalisation and expansion to >200 assembly factors created the challenge of integrating this ancestral machinery into a complex maturation programme. One solution is the formation of transient modules in which newly acquired assembly factors support deeply conserved components. Here, we…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}