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bioRxiv · 10.1101/2024.02.10.579793

Substrate recognition principles for PP2A-B55

Kruse, T.·Garvanska, D.·Varga, J. K.·Garland, W.·McEwan, B.·Hein, J.·Weisser, M. B.·Brandies Puy, I.·Chan, C.·Parrila, P. S.·Lopez-Mendez, B.·Jeyaprakash, A. A.·Schueler-Furman, O.·Jensen, T. H.·Kettenbach, A.·Nilsson, J.
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Abstract

The PP2A-B55 phosphatase regulates a plethora of signaling pathways throughout eukaryotes. How PP2A-B55 selects its substrates presents a severe knowledge gap. By integrating AlphaFold modelling with comprehensive high resolution mutational scanning, we show that -helices in substrates bind B55 through an evolutionary conserved mechanism. Despite a large diversity in sequence and composition, these -helices share key amino acid determinants that engage discrete hydrophobic and electrostatic patches. Using deep learning protein design, we generate a specific and potent competitive peptide inhibitor of PP2A-B55 substrate interactions. With this inhibitor, we uncover that PP2A-B55 regulates the nuclear exosome targeting complex by binding to an -helical recruitment module in RBM7. Collectively, our findings provide a framework for the understanding and interrogation of PP2A-B55 in health and disease. One sentence summary-helices in PP2A-B55 substrates bind a conserved pocket on B55 through a common mechanism that is conserved in eukaryotes.

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Kruse, T., Garvanska, D., Varga, J. K., Garland, W., McEwan, B., Hein, J., Weisser, M. B., Brandies Puy, I., Chan, C., Parrila, P. S., Lopez-Mendez, B., Jeyaprakash, A. A., Schueler-Furman, O., Jensen, T. H., Kettenbach, A., Nilsson, J.. 2024-02-11. Substrate recognition principles for PP2A-B55. https://doi.org/10.1101/2024.02.10.579793

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