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Hsp104 is a highly conserved protein with two essential nucleotide-binding sites
D A Parsell1, Y Sanchez, J D Stitzel
1Howard Hughes Medical Institute, University of Chicago, Illinois 60637.
Nature
|September 19, 1991
Summary
Heat-shock protein 104 (hsp104) is a conserved ClpA/ClpB family member crucial for thermotolerance. Mutagenesis confirmed two nucleotide-binding sites are essential for its function in heat stress response.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Eukaryotic cells produce high molecular mass heat-shock proteins (100-110 kDa) upon thermal stress.
- Heat-shock protein 104 (hsp104) in yeast is vital for stress tolerance.
- Mammalian hsp110 is nucleolar and its localization varies with cellular conditions.
Purpose of the Study:
- To investigate the evolutionary relationships of hsp104 and hsp110 with high molecular mass heat-shock proteins across different organisms.
- To identify the protein family to which hsp104 belongs.
- To determine the functional importance of specific domains within hsp104.
Main Methods:
- Comparative sequence analysis to identify conserved protein families.
- Gene mutagenesis to alter specific nucleotide-binding sites in hsp104.
- Functional assays to assess thermotolerance in mutated strains.
Main Results:
- Hsp104 was identified as a member of the highly conserved ClpA/ClpB protein family.
- Additional heat-inducible ClpA/ClpB family members were found in yeast (Schizosaccharomyces pombe) and mammals.
- Mutagenesis of two putative nucleotide-binding sites in hsp104 demonstrated their essentiality for thermotolerance.
Conclusions:
- Hsp104 represents a conserved heat-shock protein within the ClpA/ClpB family.
- The ClpA/ClpB family includes heat-inducible members across diverse eukaryotic organisms.
- Nucleotide-binding sites in hsp104 are critical for its role in cellular thermotolerance.