Exploring novel function of yeast Ssa1/2p by quantitative profiling proteomics using NanoESI-LC-MS/MS

Area of Science:

• Proteomics
• Molecular Biology
• Yeast Genetics

Background:

• Heat shock proteins, such as Ssa1/2p, are crucial for cellular homeostasis.
• Understanding the role of Ssa1/2p in protein regulation is essential for cellular function.

Purpose of the Study:

• To profile and quantify protein expression changes in ssa1/2 mutant yeast compared to wild-type.
• To investigate the relationship between mRNA and protein expression levels in the absence of SSA1 and SSA2.

Main Methods:

• Proteomic analysis using one-dimensional gel electrophoresis, liquid chromatography, and mass spectrometry.
• Quantitative profiling with modified N-terminal isotope tagging for differential protein expression analysis.
• Comparison of protein expression with mRNA levels.

Main Results:

• 322 proteins were identified; 103 proteins showed quantitative changes between mutant and wild-type.
• 28 proteins were up-regulated and 26 down-regulated in the ssa1/2 mutant.
• A lack of correlation between mRNA and protein expression was observed, suggesting post-transcriptional regulation.

Conclusions:

• The deletion of SSA1 and SSA2 affects protein expression at the translational or degradation levels.
• Up-regulation of chromosomal control proteins in the ssa1/2 mutant is a novel finding.
• Ssa1/2p likely plays a role in chromosomal control mechanisms.