Identification of Changing Ribosome Protein Compositions using Mass Spectrometry

Area of Science:

• Molecular Biology
• Proteomics
• Yeast Genetics

Background:

• Ribosomes, the protein synthesis machinery, are increasingly recognized for their regulatory roles in gene expression.
• Emerging evidence suggests ribosomes are dynamic complexes that can alter their protein makeup based on environmental cues.

Purpose of the Study:

• To investigate the dynamic nature of ribosomes by quantifying protein composition changes in Saccharomyces cerevisiae 80S ribosomes.
• To determine if specific paralog ribosomal proteins impact ribosome function and adaptability to environmental stimuli.

Main Methods:

• Quantitative mass spectrometry (MS) was employed to analyze protein composition changes in yeast ribosomes.
• Yeast genetics and polysome profiling were utilized to assess the functional interchangeability of specific ribosomal proteins.

Main Results:

• Significant shifts in the relative proportions of paralog yeast ribosomal proteins RPL8A (eL8A) and RPL8B (eL8B) were observed in 80S ribosomes when switching yeast growth from glucose to glycerol.
• Functional assays demonstrated that yeast ribosomes containing either RPL8A or RPL8B are not functionally equivalent.

Conclusions:

• The findings support the hypothesis that ribosomes are dynamic entities capable of altering their protein composition.
• These compositional changes correlate with altered functional activity, enabling adaptation to different growth and environmental conditions.