Monomeric 14-3-3ζ Has a Chaperone-Like Activity and Is Stabilized by Phosphorylated HspB6
| Autor: | Alfred A. Antson, Maria V. Sudnitsyna, Natalya V. Artemova, Nikolai N. Sluchanko, Nikolai B. Gusev, Dmitrii I. Levitsky, Irina V. Safenkova |
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| Rok vydání: | 2012 |
| Předmět: |
Hot Temperature
Protein family Protein subunit Mutant Biochemistry Article Phosphates 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Heat shock protein Chymotrypsin Humans HSP20 Heat-Shock Proteins Phosphorylation Protein Structure Quaternary 030304 developmental biology 0303 health sciences biology Protein Stability Myosin Subfragments Smooth muscle contraction Phosphoproteins Monomer 14-3-3 Proteins chemistry Chaperone (protein) Mutation Proteolysis Mutagenesis Site-Directed biology.protein Biophysics Protein Multimerization 030217 neurology & neurosurgery |
| Zdroj: | Biochemistry |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi300674e |
| Popis: | Members of the 14-3-3 eukaryotic protein family predominantly function as dimers. The dimeric form can be converted into monomers upon phosphorylation of Ser(58) located at the subunit interface. Monomers are less stable than dimers and have been considered to be either less active or even inactive during binding and regulation of phosphorylated client proteins. However, like dimers, monomers contain the phosphoserine-binding site and therefore can retain some functions of the dimeric 14-3-3. Furthermore, 14-3-3 monomers may possess additional functional roles owing to their exposed intersubunit surfaces. Previously we have found that the monomeric mutant of 14-3-3ζ (14-3-3ζ(m)), like the wild type protein, is able to bind phosphorylated small heat shock protein HspB6 (pHspB6), which is involved in the regulation of smooth muscle contraction and cardioprotection. Here we report characterization of the 14-3-3ζ(m)/pHspB6 complex by biophysical and biochemical techniques. We find that formation of the complex retards proteolytic degradation and increases thermal stability of the monomeric 14-3-3, indicating that interaction with phosphorylated targets could be a general mechanism of 14-3-3 monomers stabilization. Furthermore, by using myosin subfragment 1 (S1) as a model substrate we find that the monomer has significantly higher chaperone-like activity than either the dimeric 14-3-3ζ protein or even HspB6 itself. These observations indicate that 14-3-3ζ and possibly other 14-3-3 isoforms may have additional functional roles conducted by the monomeric state. |
| Databáze: | OpenAIRE |
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