14-3-3 is highly evolutionary conserved eukaryotic protein family, ubiquitously expressed in mammalian tissues. Importance of 14-3-3 protein in cell cycle and metabolism is supported by the number of interaction partners as over 1200 of them were discovered. [1] For the proper function of this rigid and highly helical protein its dimeric state is essential. [2]
7 mammalian isoforms of 14-3-3 are known: ε, γ, ζ, β, θ, η and σ. These isoforms differ in their sequences, interactoms and expression levels in various tissues, whereas their structure and general biophysical properties are similar. It is known that isoforms can form hetero- and homodimers, but propensities of isoforms to dimerise were not quantified yet. In addition, information about chemical nature of this process is ambiguous across the literature. [3, 4] Characterization of mutual affinities of 14-3-3 isoforms is target of this work.
To study the isoform dimerization, we used fluorimetric experiments based on fluorescence resonance energy transfer (FRET), designed previously in our group. Such measurements provide insight into kinetics of dimerization including rate and dissociation constants. [5] Previously, our colleagues were able to characterise dimerization of ζ isoform. In this study, we extended the knowledge to homodimerization of ε, σ, γ and heterodimerization of γζ and ζε. We focused on dimerization properties at different temperatures and NaCl concentrations. From the dependency of rate constant on temperature we determined Arrhenius parameters. On the other hand, we did not observe significant trend in the dependency of dimerization parameters on NaCl concentration, indicating low effect of ionic strength on dimer formation.
CIISB, Instruct-CZ Centre of Instruct-ERIC EU consortium, funded by MEYS CR infrastructure project LM2018127, is gratefully acknowledged for the financial support of the measurements at the CF Biomolecular Interactions and Crystallization.
This study was financed by the Czech Science Foundation (no. GF20-05789L).
[1] N. N. Sluchanko a D. M. Bustos, in Progress in Molecular Biology and Translational Science, roč. 166, Elsevier, 2019, s. 19–61.
[2] N. N. Sluchanko a N. B. Gusev, , FEBS Lett, roč. 586, č. 24, s. 4249–4256, pro. 2012
[3] X. Yang et al., Proc Natl Acad Sci U S A, roč. 103, č. 46, s. 17237–17242, lis. 2006
[4] Z. Jandova, Z. Trosanova, V. Weisova, C. Oostenbrink, a J. Hritz,, Biochim Biophys Acta Proteins Proteom, 2018
[5] T. Trošanová Z, Louša P, Kozeleková A, Brom T, Gašparik N, Tungli J, Weisová V, Župa E, Žoldák G, Hritz J., 2022