Cooperative mechanics of PR65 scaffold underlies the allosteric regulation of the phosphatase PP2A
Date
2023
Authors
Kaynak, Burak T.
Dahmani, Zakaria L.
Doruker, Pemra
Banerjee, Anupam
Yang, Shang-Hua
Gordon, Reuven
Itzhaki, Laura S.
Bahar, Ivet
Journal Title
Journal ISSN
Volume Title
Publisher
Structure
Abstract
Summary:
PR65, a horseshoe-shaped scaffold composed of 15 HEAT (observed in Huntingtin, elongation factor 3, protein phosphatase 2A, and the yeast kinase TOR1) repeats, forms, together with catalytic and regulatory subunits, the heterotrimeric protein phosphatase PP2A. We examined the role of PR65 in enabling PP2A enzymatic activity with computations at various levels of complexity, including hybrid approaches that combine full-atomic and elastic network models. Our study points to the high flexibility of this scaffold allowing for end-to-end distance fluctuations of 40–50 Å between compact and extended conformations. Notably, the intrinsic dynamics of PR65 facilitates complexation with the catalytic subunit and is retained in the PP2A complex enabling PR65 to engage the two domains of the catalytic subunit and provide the mechanical framework for enzymatic activity, with support from the regulatory subunit. In particular, the intra-repeat coils at the C-terminal arm play an important role in allosterically mediating the collective dynamics of PP2A, pointing to target sites for modulating PR65 function.
Description
Keywords
PR65, PP2A, allostery, collective dynamics, conformational mechanics, elastic network models, hybrid simulations, repeat protein
Citation
Kaynak, B. T., Dahmani, Z. L., Doruker, P., Banerjee, A., Yang, S-H., Gordon, R., Itzhaki, L. S., & Bahar, I. (2023). Cooperative mechanics of PR65 scaffold underlies the allosteric regulation of the phosphatase PP2A. Structure, 31(5), 607-618.e3. https://doi.org/10.1016/j.str.2023.02.012