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Abnormal proteins enhance stress-induced cell death
Biochemical and Biophysical Research Communications
|February 25, 1998
Summary
Abnormal proteins can impact cell viability. Artificially cleaved Escherichia coli methionyl-tRNA synthetase (MetRS) retained activity but caused cell death under stress, suggesting misfolded proteins threaten cell survival.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Cell viability relies on functional proteins.
- Escherichia coli methionil-tRNA synthetase (MetRS) is crucial for protein synthesis and cell survival.
- Protein domains and their roles in enzyme activity are key to understanding cellular function.
Purpose of the Study:
- To investigate the impact of artificially cleaved proteins on cell viability.
- To determine if split MetRS retains enzymatic activity and affects cell survival.
- To explore the role of chaperonins in the function and cellular effects of abnormal protein structures.
Main Methods:
- Artificially cleaving Escherichia coli methionil-tRNA synthetase (MetRS) via linker insertion to create two polypeptide fragments.
- Expressing and analyzing the aminoacylation activity of the split MetRS mutants in vitro.
- Assessing cell viability and stress sensitivity in cells expressing the split MetRS mutants, with and without chaperonin (GroESL) induction.
Main Results:
- Split MetRS mutants, cleaved within domains or at domain junctions, retained in vitro aminoacylation activity.
- In vitro activity of split MetRS was enhanced by the presence of chaperonin GroESL.
- Cells expressing split MetRS polypeptides exhibited increased sensitivity to conditions that induce GroESL, indicating compromised cell viability under stress.
Conclusions:
- Artificially cleaved proteins can maintain partial function.
- Abnormal protein structures, even if partially active, can lead to cell death under stressful conditions.
- Chaperonin systems may influence the cellular consequences of protein misfolding or fragmentation.