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Peer-reviewedCC BYScience Advances

Structural basis for start codon selection by eIF5-mimic proteins

  • Ximena Zottig1,2
  • Chun-Ying Huang1
  • Zahra Seraj1
  • Nikolaus Grigorieff1,2
  • Andrei A. Korostelev1
  1. 1RNA Therapeutics Institute, UMass Chan Medical School, 368 Plantation Street, Worcester, MA 01605, USA.
  2. 2Howard Hughes Medical Institute, UMass Chan Medical School, 368 Plantation Street, Worcester, MA 01605, USA.
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Abstract

Start codon selection extensively regulates the cellular proteome and is implicated in cancer and other diseases. The eIF5-mimic proteins (5MPs: 5MP1/BZW2 and 5MP2/BZW2) restrict non-AUG start codon usage and thereby reprogram proteoform expression from mRNAs with alternative start sites, such as the oncogenic c-Myc. Here, using in extracto cryo-electron microscopy (cryo-EM) and biochemical assays, we report how 5MP represses translation dependent on the sequence context at start codons. Cryo-EM structures of 48S preinitiation complexes (PICs) reveal 5MP1 bound at the A site of the small ribosomal subunit. 5MPs act as initiation factors that stabilize an open PIC conformation, promoting mRNA scanning and inhibiting initiation at suboptimal start codons. We propose to designate 5MP as eIF1S (eukaryotic initiation factor 1 scanning). These findings reveal the structural basis for proteome modulation by 5MPs and may help correct dysregulated translation in disease.

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Cite

BibTeXRIS
BibTeX
@article{zottig2026structural,
  title = {{Structural basis for start codon selection by eIF5-mimic proteins}},
  author = {Ximena Zottig and Chun-Ying Huang and Zahra Seraj and Nikolaus Grigorieff and Andrei A. Korostelev},
  journal = {Science Advances},
  year = {2026},
  month = oct,
  doi = {10.1126/sciadv.aeg5840},
  url = {https://www.science.org/doi/10.1126/sciadv.aeg5840},
  note = {CC BY},
}
RIS
TY  - JOUR
TI  - Structural basis for start codon selection by eIF5-mimic proteins
AU  - Ximena Zottig
AU  - Chun-Ying Huang
AU  - Zahra Seraj
AU  - Nikolaus Grigorieff
AU  - Andrei A. Korostelev
PY  - 2026
DA  - 2026/10/23
JO  - Science Advances
DO  - 10.1126/sciadv.aeg5840
UR  - https://www.science.org/doi/10.1126/sciadv.aeg5840
AB  - Start codon selection extensively regulates the cellular proteome and is implicated in cancer and other diseases. The eIF5-mimic proteins (5MPs: 5MP1/BZW2 and 5MP2/BZW2) restrict non-AUG start codon usage and thereby reprogram proteoform expression from mRNAs with alternative start sites, such as the oncogenic c-Myc. Here, using in extracto cryo-electron microscopy (cryo-EM) and biochemical assays, we report how 5MP represses translation dependent on the sequence context at start codons. Cryo-EM structures of 48S preinitiation complexes (PICs) reveal 5MP1 bound at the A site of the small ribosomal subunit. 5MPs act as initiation factors that stabilize an open PIC conformation, promoting mRNA scanning and inhibiting initiation at suboptimal start codons. We propose to designate 5MP as eIF1S (eukaryotic initiation factor 1 scanning). These findings reveal the structural basis for proteome modulation by 5MPs and may help correct dysregulated translation in disease.
SN  - 2375-2548
ER  -