Biological factors and statistical limitations prevent detection of most noncanonical proteins by mass spectrometry

Copyright: © 2023 Wacholder, Carvunis. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited..

Ribosome profiling experiments indicate pervasive translation of short open reading frames (ORFs) outside of annotated protein-coding genes. However, shotgun mass spectrometry (MS) experiments typically detect only a small fraction of the predicted protein products of this noncanonical translation. The rarity of detection could indicate that most predicted noncanonical proteins are rapidly degraded and not present in the cell; alternatively, it could reflect technical limitations. Here, we leveraged recent advances in ribosome profiling and MS to investigate the factors limiting detection of noncanonical proteins in yeast. We show that the low detection rate of noncanonical ORF products can largely be explained by small size and low translation levels and does not indicate that they are unstable or biologically insignificant. In particular, proteins encoded by evolutionarily young genes, including those with well-characterized biological roles, are too short and too lowly expressed to be detected by shotgun MS at current detection sensitivities. Additionally, we find that decoy biases can give misleading estimates of noncanonical protein false discovery rates, potentially leading to false detections. After accounting for these issues, we found strong evidence for 4 noncanonical proteins in MS data, which were also supported by evolution and translation data. These results illustrate the power of MS to validate unannotated genes predicted by ribosome profiling, but also its substantial limitations in finding many biologically relevant lowly expressed proteins.

Errataetall:

UpdateOf: bioRxiv. 2023 Oct 31;:. - PMID 36945638

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:21

Enthalten in:

PLoS biology - 21(2023), 12 vom: 04. Dez., Seite e3002409

Sprache:

Englisch

Beteiligte Personen:

Wacholder, Aaron [VerfasserIn]
Carvunis, Anne-Ruxandra [VerfasserIn]

Links:

Volltext

Themen:

Biological Factors
Journal Article
Proteins

Anmerkungen:

Date Completed 16.12.2023

Date Revised 21.12.2023

published: Electronic-eCollection

UpdateOf: bioRxiv. 2023 Oct 31;:. - PMID 36945638

Citation Status MEDLINE

doi:

10.1371/journal.pbio.3002409

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM365393150