Effect of Arginine on Chaperone-Like Activity of HspB6 and Monomeric 14-3-3ζ.

Valeriya V Mikhaylova,Daria I Kalacheva,Vladimir V Shubin,Tatiana B Eronina,Boris I Kurganov,Natalia A Chebotareva

doi:10.3390/ijms21062039

Abstract

The effect of protein chaperones HspB6 and the monomeric form of the protein 14-3-3ζ (14-3-3ζm) on a test system based on thermal aggregation of UV-irradiated glycogen phosphorylase b (UV-Phb) at 37 °C and a constant ionic strength (0.15 M) was studied using dynamic light scattering. A significant increase in the anti-aggregation activity of HspB6 and 14-3-3ζm was demonstrated in the presence of 0.1 M arginine (Arg). To compare the effects of these chaperones on UV-Phb aggregation, the values of initial stoichiometry of the chaperone–target protein complex (S0) were used. The analysis of the S0 values shows that in the presence of Arg fewer chaperone subunits are needed to completely prevent aggregation of the UV-Phb subunit. The changes in the structures of HspB6 and 14-3-3ζm induced by binding of Arg were evaluated by the fluorescence spectroscopy and differential scanning calorimetry. It was suggested that Arg caused conformational changes in chaperone molecules, which led to a decrease in the thermal stability of protein chaperones and their destabilization.

Highlights

Protein aggregation is a universal and unfavorable process for all cells, leading to production of non-native protein structures
The effect of protein chaperones HspB6 and the monomeric form of the protein 14-3-3ζ (14-3-3ζm) on a test system based on thermal aggregation of UV-irradiated glycogen phosphorylase b (UV-Phb) at 37 ◦C and a constant ionic strength (0.15 M) was studied using dynamic light scattering
The studies were carried out using the method of dynamic light scattering (DLS) under physiological conditions: at a temperature of 37 ◦C and an ionic strength of 0.15 M

Summary

Introduction

Protein aggregation is a universal and unfavorable process for all cells, leading to production of non-native protein structures. Accumulation of toxic aggregates in cells is associated with a number of neurodegenerative diseases [1,2,3,4,5,6]. Cells have protective mechanisms that allow them to minimize the risk of protein aggregation [7,8]. Small heat shock proteins (sHsps) belong to the family of molecular chaperones and protect cells against different kind of stresses, serving as a first line of defense in preventing protein aggregation [9,10,11]. One of the most important functions of sHsps is to prevent protein aggregation by binding of non-native or misfolded protein molecules and hold them in a folding-competent conformation. SHsps are involved in the regulation of many cellular processes and assist in the maintenance of protein homeostasis [10]

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Results

Conclusion