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Evaluation of the Impact of Protein Aggregation on Cellular Oxidative Stress in Yeast
Published on: June 23, 2018
Yar1 protects the ribosomal protein Rps3 from aggregation
Barbara Koch1, Valentin Mitterer, Johannes Niederhauser
1Institut für Molekulare Biowissenschaften, Universität Graz, Humboldtstrasse 50, A-8010 Graz, Austria.
The Journal of Biological Chemistry
|May 10, 2012
Summary
Yeast protein Yar1 acts as a specific chaperone for ribosomal protein Rps3, preventing its aggregation and ensuring its proper incorporation into ribosomal subunits for cell growth. This interaction is crucial for ribosome biogenesis.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Ribosome synthesis is essential for cell growth, requiring rapid production and nuclear import of ribosomal proteins.
- Efficient ribosome biogenesis depends on the coordinated synthesis, transport, and assembly of ribosomal proteins and RNA.
- The yeast Saccharomyces cerevisiae requires the synthesis of 2000 ribosomes per minute for optimal growth.
Purpose of the Study:
- To investigate the role of the ankyrin repeat protein Yar1 in the biogenesis of ribosomal subunits.
- To determine the interaction between Yar1 and the small ribosomal subunit protein Rps3.
- To elucidate the function of Yar1 in maintaining Rps3 solubility and facilitating its nuclear import.
Main Methods:
- Yeast genetics and molecular biology techniques were employed.
- Protein interaction studies were performed to assess the binding of Yar1 and Rps3.
- Phenotypic analysis of yeast strains with mutations or altered expression of Yar1 and Rps3 was conducted.
- In vitro and in vivo solubility assays were used to evaluate Rps3 aggregation.
Main Results:
- Yar1 directly interacts with Rps3 and escorts it from the cytoplasm to the nucleus for ribosome assembly.
- Deletion of Yar1 in yeast leads to phenotypes similar to Rps3 mutants, including 20S pre-rRNA accumulation and 40S export defects.
- Combined rps3 mutation and yar1 deletion exacerbate these phenotypes, while increased RPS3 expression rescues yar1 deletion defects.
- Yar1 demonstrates chaperone activity by protecting Rps3 from aggregation and enhancing its solubility.
Conclusions:
- Yar1 functions as a specific chaperone for Rps3, crucial for its solubility and proper incorporation into pre-ribosomal subunits.
- This chaperone activity of Yar1 is vital for efficient ribosome biogenesis and optimal yeast growth.
- The findings highlight a specialized mechanism for ribosomal protein handling during ribosome assembly.
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